Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Protein quality of pig diets : processing effects on amino acid digestibility and post-absorptive utilization
Hulshof, Tetske - \ 2016
Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Paul Bikker; Thomas van der Poel. - Wageningen : Wageningen University - ISBN 9789462579026 - 175
pigs - protein quality - pig feeding - feeds - feed processing - amino acids - protein digestibility - digestive absorption - protein utilization - nutrition physiology - animal nutrition - varkens - eiwitkwaliteit - varkensvoeding - voer - voedermiddelbewerking - aminozuren - eiwitverteerbaarheid - verteringsabsorptie - eiwitgebruik - voedingsfysiologie - diervoeding

The increasing world population and per capita income imposes a risk for protein scarcity. It is, therefore, necessary to use current ingredients more efficiently which includes the accurate assessment of protein quality before inclusion in animal diets. Protein quality is defined in this thesis as the capacity of a dietary protein to meet a pig’s requirement for nitrogen (N) and amino acids (AA) to meet a particular production target. Protein quality is influenced by processing applied to feed ingredients which may lead to the formation of Maillard reaction products (MRP) or cross-link products. The Maillard and cross-link reactions mainly involve lysine (Ly)s and their products may decrease ileal crude protein (CP) digestibility. During the acid hydrolysis step used to analyze AA, part of the early MRP revert back to Lys. This reverted Lys is not bioavailable for animals. Therefore, methods that specifically analyze Lys with a free ε-amino group (that is, not bound to other nutrients) have been developed. The guanidination reaction with O-methylisourea (OMIU) is one such method. The initial aim of this thesis was to evaluate the ileal digestible reactive Lys assay as a more accurate measure for protein quality of processed protein sources than the ileal digestible total Lys assay. Soybean meal (SBM) and rapeseed meal (RSM) were used as sole protein sources throughout this thesis. Processing of SBM and RSM by toasting at 95°C for 30 min in the presence of a sugar-rich lignosulfonate was used as model for over-processed protein sources.

Digestibility, post-absorptive utilization, and pig growth performance

In Chapter 2, protein quality in processed protein sources was determined using the content of AA, OMIU-reactive Lys, MRP, and lysinoalanine (LAL; as cross-link product), the standardized ileal digestibility (SID) of AA and OMIU-reactive Lys and pig growth performance. The SBM and RSM diets contained furosine and carboxymethyllysine (CML) as MRP, and LAL indicating that the Maillard and cross-link reactions had taken place in SBM and RSM, presumably during the oil extraction/desolventizing process. The amounts of furosine, CML, and LAL were elevated in the pSBM and pRSM diets due to further processing. Processing resulted in a reduction in total and OMIU-reactive Lys contents, a decreased pig growth performance as determined by the gain to feed ratio (G:F), and the SID of CP, AA, and OMIU-reactive Lys. The SID AA contents of the protein sources from Chapter 2 were used to formulate the diets of the main in vivo experiment (Chapters 3 and 4). In this experiment, six experimental diets were used of which four contained either SBM, pSBM, RSM, or pRSM as sole protein source. The remaining two experimental diets contained pSBM or pRSM and were supplemented with crystalline AA to the same SID AA levels as the SBM or RSM diet. These supplemented diets were used to verify that processing affected AA digestibility rather than post-absorptive AA utilization. The effects of processing on CP digestibility and N solubilization along the small intestine, metabolic load as assessed by organ weight, and nutrient composition of the empty body of growing pigs are described in Chapter 3. The small intestine was divided in three segments of similar length and digesta was collected from the last 100 cm of each segment. The amount of insoluble N as a fraction of N in digesta at each small intestinal segment was not affected by processing. Thus, the reduced SID of CP and AA reported in Chapter 2 was not caused by a reduced N solubility but by a general increase of N in digesta. Processing reduced the SID of CP, CP content in the empty body, and G:F. Supplementing crystalline AA to diets containing pSBM or pRSM increased the CP content and G:F to the level of the SBM and RSM diets. Processing also reduced the weight of several organs and supplementing crystalline AA restored organ weight. The effects of processing on whole body AA composition, nutrient retention, and post-absorptive utilization of AA in growing pigs are described in Chapter 4. Post-absorptive AA utilization was calculated as percentage of SID AA intake used for AA retention. Processing affected the AA composition of protein in the organ fraction (that is, empty organs and blood), carcass, and empty body. The Lys concentration in body protein was mainly reduced by processing. Supplementing crystalline AA restored the AA composition of body protein for SBM and RSM. Processing reduced AA retention and again supplementing crystalline AA restored AA retention for both SBM and RSM. Since crystalline AA were supplemented on an SID AA basis, the results indicated that processing affected AA digestibility but not post-absorptive AA utilization. Thus, correcting AA retention for SID AA intake would result in a similar post-absorptive AA utilization which was found for most AA for the RSM diets. However, the post-absorptive AA utilization was lower for the pSBM diet than for the SBM diet which might be related to an imbalanced AA supply after absorption in the first diet.

The assessment of ileal digestibility and utilization is expensive and laborious. Therefore, two alternative in vitro methods for determining protein digestibility for processed protein sources were evaluated (Chapter 5). The protein digestibility determined using the pH-STAT method and a 2-step enzymatic method was compared with the in vivo SID of CP reported in Chapter 2. Initial pH and the degree of hydrolysis assessed in the pH-STAT method were positively correlated to SID of CP. Protein digestibility determined with the 2-step enzymatic method, simulating digestion in the stomach and small intestine, tended to correlate to SID of CP. Both the 2-step enzymatic method and pH-STAT method were suitable alternatives for the assessment of SID of CP. However, only four ingredients were tested. The suitability of the methods should be further studied using multiple (processed) feed ingredients before they can be used as alternatives for in vivo assays.

Reactive Lys analysis

O-methylisourea was reported to bind specifically to the ε-amino group of Lys. The results of Chapter 2, however, cast doubt on the specificity of OMIU to react only with the ε-amino group of Lys. A series of experiments was conducted to study this specificity (Chapter 6). Incubating crystalline L-Lys with OMIU under standard conditions (OMIU pH of 10.6, OMIU to AA ratio of 1000:1, and reaction time of 7 d) resulted in a low homoarginine (that is, Lys with OMIU bound to its ε-amino group) recovery. The reaction of OMIU with the α-amino group of Lys was confirmed by mass spectrometry analysis with double derivatized Lys being identified. Several reaction conditions (OMIU pH, OMIU to Lys ratio, and reaction time) were studied but none of these resulted in 100% recovery of homoarginine. Binding of OMIU to the α-amino group of Lys could result in an underestimation of the reactive Lys content when significant levels of Lys with a free α-amino group (that is, crystalline L-Lys (HCl), free and N-terminal Lys) are present in food/feed ingredients, diets, and ileal digesta. The free Lys content in food/feed ingredients was on average 1.3% of total Lys. The free Lys content can be substantial in certain diets and was reported to be 13% of total Lys in ileal digesta. The latter might result in an overestimation of the OMIU-reactive Lys digestibility. The reaction of OMIU with α-amino groups may necessitate analysis of free Lys to accurately quantify reactive lysine in samples containing a large proportion of Lys with a free α-amino group.

The results presented in this thesis indicate that the effects of processing on SID of CP and AA, body composition, nutrient retention, post-absorptive AA utilization, and growth performance could be substantial. These effects should, therefore, be taken into account when using processed feed ingredients in diets for growing pigs. The extent of protein damage in feed ingredients can be assessed by the analysis of OMIU-reactive and total Lys, MRP, and cross-link products. However, OMIU-reactive Lys only provides accurate results when samples contain small levels of Lys with a free α-amino group (that is, crystalline L-Lys (HCl), free and N-terminal Lys). When samples contain significant levels of Lys with a free α-amino group, it is recommended to use standard guanidination conditions (OMIU pH of 10.6, OMIU to AA ratio of 1000:1, and reaction time of 7 d) to convert protein-bound Lys to homoarginine and to separately analyze such samples for free Lys.

Succesvol weiden tijdens voorjaar en najaar in Nederland
Snip, Karst-Jan ; Kwakernaak, C. ; Stienezen, M.W.J. - \ 2016
Wageningen UR Livestock Research - 1
dierenwelzijn - dierlijke productie - melkvee - huisvesting, dieren - begrazing - diervoeding - animal welfare - animal production - dairy cattle - animal housing - grazing - animal nutrition
Sainfoin (Onobrychis viciifolia) : a forgotten crop for dairy cows with future potential
Huyen, Nguyen Thi - \ 2016
Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Wilbert Pellikaan; Martin Verstegen. - Wageningen : Wageningen University - ISBN 9789462577268 - 160
onobrychis viciifolia - dairy cows - fodder legumes - fodder crops - legume silage - rumen digestion - nutrition physiology - methane production - milk yield - dairy performance - animal nutrition - onobrychis viciifolia - melkkoeien - voederpeulvruchten - voedergewassen - peulvruchtenkuilvoer - pensvertering - voedingsfysiologie - methaanproductie - melkopbrengst - melkresultaten - diervoeding

Sainfoin (Onobrychis viciifolia): a forgotten crop for dairy cows with future potential

SUMMARY

The world population growth and rising incomes are expected to increase the consumption of animal-derived foods such as meat, eggs and milk. However, livestock production should not only be directed towards increasing productivity but should also incorporate environmental, food safety and animal welfare aspects. Therefore, farm businesses have to respond to the high environment impact of their activities, by using low-input systems including the use of forage legumes. Recent studies have demonstrated that forage legumes with moderate levels of condensed tannins (CT) are beneficial for animal nutrition and animal health. Sainfoin (Onobrychis viciifolia Scop.) is a tanniniferous forage legume containing CT that has potential nutritional and health benefits, i.e. preventing bloating, reducing nematode larval establishment, improving nitrogen (N) utilization and reducing greenhouse gas and N emissions (Chapter 1). However, the use of sainfoin as a fodder crop in dairy cow rations in northwestern Europe is still rather unknown. This thesis investigated the potential of sainfoin in the dairy cow diets and the effect of CT structural properties on rumen fermentation and biohydrogenation (BH).

Chapter 2 reports a study where the effect of sainfoin silage on nutrient digestibility, animal performance, energy and N utilization and methane (CH4) production in dairy cows was investigated. Six rumen cannulated, lactating dairy cows were randomly assigned to either a control (CON) or sainfoin based (SAIN) diet. The CON diet was a mixture of grass silage, corn silage, concentrate and linseed. In the SAIN diet, 50% of the grass silage DM in the CON diet was exchanged by sainfoin silage. Total daily dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) intake did not differ between the two diets. The apparent digestibility of DM, OM, NDF and acid detergent fiber (ADF) were respectively, 5.7, 4.0, 15.7 and 14.8% lower for the SAIN diet. Methane production per kg DM intake was lowest for the SAIN diet and CH4 production as a percentage of gross energy intakes tended to be lower while milk yield was greater for the SAIN diet. Nitrogen intake, N retention and energy retained in body protein were greater for the SAIN than the CON diet. Nitrogen retention as a percentage of N intake tended to be greater for the SAIN diet. These results showed that inclusion of sainfoin silage at the expense of grass silage in dairy cow rations reduced CH4 per kg DM intake. Although nutrient digestibility was decreased, sainfoin silage improved milk production and redirected metabolism towards body protein accretion at the expense of body fat.

In Chapter 3, reticular fatty acid (FA) flow and ruminal BH of C18:3n-3 is reported using the reticular sampling technique (Cr-EDTA and Yb-acetate as digesta flow markers) in the lactating cows fed the SAIN and CON diet in Chapter 2. The reticular flows of DM, OM and N were not affected by dietary treatment. However, NDF flow was higher (1.87 vs. 1.40 kg/d) where the cows were fed the SAIN diet. A higher mono-unsaturated FA flow was caused by the higher trans-9-C18:1 and cis-9-C18:1 flow for the SAIN compared to the CON fed cows. The flows of trans-9,trans-12-C18:2 and cis-12,trans-10 C18:2 were higher in the SAIN diet fed cows, but total poly-unsaturated FA flow was not affected by the different diet treatments. The SAIN diet fed cows had a significant lower ruminal BH of cis-9-C18:1 and C18:3n-3, compared to the CON fed cows and tended to a lower ruminal BH in case of cis-9,cis-12-C18:2. These results show that inclusion of sainfoin silage at the expense of grass silage in dairy cow rations reduces ruminal BH of dietary cis-9-C18:1 and C18:3n-3.

The effects of replacing grass silage by sainfoin silage in a TMR on milk production and FA in milk fat of the dairy cows in Chapter 2 is reported in Chapter 4. Milk yield reported in Chapter 4 was highest for the SAIN diet with every kg of OM digested of the SAIN diet resulting, on average, in 0.2 kg more milk production. The SAIN diet fed cows had a higher C18:3n-3 and cis-9,cis-12-C18:2 proportion in milk fat compared to the CON diet fed cows. A higher proportion of total trans-C18:1 was found in the cows fed the SAIN diet. There were no differences in proportion of total saturated and unsaturated FA in milk fat between the two diets. Our results showed that replacing grass silage by sainfoin silage improved milk yield and milk FA profile of dairy cows.

Effects of the structural properties of CT, i.e. average polymer size (or mean degree of polymerization, mDP); percentage of cis flavan-3-ols (%cis) and percentage of prodelphinidins (%PD) in CT extracts on CH4 production and fermentation characteristics of rumen fluid using an in vitro gas production technique was investigated in Chapter 5. Extracts of CT from eight plants; black currant leaves, goat willow leaves, goat willow twigs, pine bark, red currant leaves, sainfoin plants, weeping willow catkins and white clover flowers were extracted, in order to obtain CT with a wide range in mDP, %PD and %cis. All CT extracts reduced CH4 concentration, decreased the maximum rate of fermentation for CH4 production and rate of substrate degradation. The correlation between CT structure on the one hand and CH4 production and fermentation characteristics on the other hand showed that the %PD within CT had the largest effect on fermentation characteristics, followed by mDP and %cis.

Chapter 6 reports results of an in vitro study to investigate the effects of the structural properties CT (mDP, %cis and %PD) on rumen fermentation and BH end-products. The total volatile FA (VFA), ammonia concentration and the proportion of branched chain VFA was reduced in all CT extracts, compared to the control. The proportion of cis-9-C18:1; cis-9,cis-12-C18:2; cis-9,cis-12,cis-15-C18:3 were numerically higher in all CT sources, while the proportion of C18:0 and fractional rate of BH of C18:3n-3 were numerically lower in all CT sources, compared to the control. The correlation between CT structural properties on the one hand and fermentation and BH end-products on the other hand showed that the CT with a high %PD and smaller mDP had the largest effect on fermentation end-products. However, mDP was found to be the most important factor affecting rumen BH.

Chapter 7 provides a general synthesis on the major findings of the studies presented in the preceding chapters. In addition, results are reported of a further in vitro as well as an in situ study in which I investigated the mechanisms of CT action in the rumen, in the post-rumen compartments and digestive tract. In the in situ study, fresh sainfoin (Esparcette) was incubated in the rumen and in the abomasum before digested during passage through the digestive tract. For the in vitro study, sainfoin (Ambra) was incubated with rumen fluid buffer for 1, 2, 4, 8, 12, 24 hours. After incubation in situ and in vitro, the incubated material was analyzed for tannin content by butanol-HCl assay. The results showed that the soluble CT dramatically reduced upon introduction in the digestive tract. Additional analyses showed that CT had bound to the fiber and protein (diet and microbes) fractions in the digestive tract.

The present work showed that sainfoin silage can be used in dairy cow rations to improve milk production and N utilization and reduce CH4 emissions per kg DM intake. Moreover, sainfoin silage, when replacing part of the grass silage in a TMR of dairy cows, increases ruminal unsaturated FA flow into the reticulum and reduces ruminal BH of dietary cis-9-C18:1 and C18:3n-3. Cows fed sainfoin silage at the expense of grass silage in a TMR increase the proportion of unsaturated FA in milk fat. In terms of condensed tannin structure, mDP and %PD appear to be the most important properties of CT that affect fermentation and BH end-products. Condensed tannins with a mDP ranging from 5 to 10 monomeric units and a %PD > 70.0% seem to have the highest biological activity in the rumen.

Influence of pectin supplementation on feed fermentation characteristics in rats and pigs
Tian, L. - \ 2016
Wageningen University. Promotor(en): Harry Gruppen; Henk Schols. - Wageningen : Wageningen University - ISBN 9789462577282 - 142
pigs - rats - pectins - feed supplements - dietary fibres - digestion - digestive tract - carbohydrates - microbial flora - nutrition physiology - animal nutrition - food chemistry - varkens - ratten - pectinen - voedersupplementen - voedingsvezels - spijsvertering - spijsverteringskanaal - koolhydraten - microbiële flora - voedingsfysiologie - diervoeding - voedselchemie

The physiological effects of dietary fiber (DFs) depend on several factors including structural features of the DFs, composition and activity of colonic microbiota, and products formed during fermentation. In this thesis, the influence of pectin supplementation to feed fermentation characteristics in rats and pigs was studied. The non-starch polysaccharides (NSP) present in the selected feed ingredient oats were characterized. Distinct populations of arabinoxylans (AXs) were observed in oats, compared to those reported for other cereals like wheat and barley. The fate of cereal AXs and soybean pectin during fermentation and the consequent effects on appetite regulation and fat accumulation were studied in rats as a model. Oat AXs were fermented less rapidly than wheat AXs in the caecum of rats. Soy pectin was fermented more early and efficiently than cereal AXs. A significant inverse correlation between rat retroperitoneal fat-pad weight and concentration and relative SCFA proportion of butyrate was observed. In a following in vivo rat experiment, commercial soy pectin together with three other soluble pectins originating from citrus and sugar beet and differing in their methyl esterification were individually supplemented to the diets. Their effects on the utilization of the different DFs present in the feed and the consequent effect on the microbial community in the colon of rats was studied. All pectins were fermented rapidly and consequently shifted fermentation of other consumed DFs (e.g. cereal AXs) to more distal part of colon, although low-methyl esterified pectin was more efficiently fermented by the microbiota than high-methyl esterified pectin. Results suggested that pectins can confer beneficial health effects through modulation of the gut microbiota. In a last in vivo experiment, citrus pectins together with a hydrothermal treated soybean meal were supplemented to pig diets to study their effect on the digestion and fermentation of carbohydrates in both the small and large intestine. Pectins, and more particularly low-methyl esterified pectin, decreased the ileal digestibility of digestible starch resulting in more starch to be fermentated in the proximal colon of pigs. Consequently, also the fermentation patterns of DFs and the microbiota composition was affected. All pectins tested shaped the colonic microbiota from a Lactobacillus-dominated microbiota to a Prevotella-dominated community, with potential health-promoting effects.

Ontwikkeling pluimveehouderij met focus op dierenwelzijn - Dierenwelzijn in beeld
Ruis, M.A.W. - \ 2016
You Tube
pluimvee - dierlijke productie - dierenwelzijn - diergedrag - huisvesting, dieren - diervoeding - diergezondheid - dierethiek - domesticatie - kippen - pluimveehouderij - lesmaterialen - poultry - animal production - animal welfare - animal behaviour - animal housing - animal nutrition - animal health - animal ethics - domestication - fowls - poultry farming - teaching materials
De hedendaagse kip is ontstaan uit vier wilde rassen. Het Bankivahoen uit Zuid-Oost Azie is hiervan de belangrijkste. Vanaf 1.500 vóór Christus verspreidde het hoen zich door heel Zuid-Oost Azië, China en Japan. In Noordwest Europa is de kip vermoedelijk rond 200 voor Christus geïntroduceerd door de Grieken en Romeinen. In de jaren ’50 van de vorige eeuw werd in Nederland op grote schaal geïnvesteerd in innovaties en verschenen de grote broedmachines en de eerste volautomatische legbatterijen. Ook kwamen begin jaren ’50 verschillende ‘merken’ hybride kippen - kruisingen van zuivere lijnen of rassen - op de markt. Hieruit ontstonden de hoogproductieve leghennen en vleeskuikens.

Halverwege de jaren ’60 dringt in de maatschappij het besef door dat er weinig oog is voor het welzijn van kippen. Decennia later heeft dit geleid tot een aantal veranderingen en verboden. Vanaf 2012 is het in heel Europa verboden om leghennen in legbatterijen te houden, en het aantal vleeskuikens per vierkante meter is in Europa aan banden gelegd. Een ander voorbeeld is de aankomende plicht om leghennen, en vermeerderingsdieren voor de vleessector, met hele snavels te houden. De pluimveesector is de uitdaging aangegaan om vlees en eieren duurzamer te produceren.
Ontwikkeling varkenshouderij met focus op dierenwelzijn - Dierenwelzijn in beeld
Ruis, M.A.W. - \ 2016
Wageningen UR Livestock Research
pigs - animal production - animal welfare - animal housing - animal nutrition - animal health - animal ethics - domestication - pig farming - teaching materials - varkens - dierlijke productie - dierenwelzijn - huisvesting, dieren - diervoeding - diergezondheid - dierethiek - domesticatie - varkenshouderij - lesmaterialen
De geschiedenis van het varken gaat terug naar de eerste boeren die wilde zwijnen gingen houden. Ongeveer 6.000 jaar vóór Christus zouden in Iran en Irak de eerste varkens uit zwijnen zijn gedomesticeerd. De eerste landbouwers met tamme varkens vestigden zich ongeveer 5.000 jaar vóór Christus in Nederland. Het varken is altijd een vaste bewoner van boerenbedrijven geweest. Varkens waren natuurlijk leveranciers van spek en vlees, maar ze ploegden ook de akkers om, zorgden voor bemesting en ze verwerkten ook afval van de boerderij. Na de Tweede Wereldoorlog werd de varkenshouderij enorm geïndustrialiseerd: schaalvergroting, mechanisatie, en specialisatie werden gestimuleerd. Men keek in de jaren vijftig tot zeventig van de vorige eeuw met een zakelijke blik naar het dier; de economische voordelen waren het belangrijkst. Vanaf halverwege de jaren zestig nam de aandacht voor dierenwelzijn toe, en dit heeft geleid tot een aantal verboden en verplichtingen. Voorbeelden zijn een verbod op de volledige roostervloeren en het aanbinden van de zeugen, en verplichte groepshuisvesting voor drachtige zeugen. De varkenshouderij is de uitdaging aangegaan om varkensvlees duurzamer te produceren.
Purifying manure effluents with duckweed
Timmerman, M. ; Hoving, I.E. - \ 2016
Wageningen UR Livestock Research (Livestock Research rapport 942) - 27
animal manures - effluents - lemna - aquatic weeds - feeds - nutrients - ingredients - animal feeding - animal nutrition - waste water - biogas - biomass production - cultivation - biobased economy - dierlijke meststoffen - afvoerwater - lemna - schadelijke waterplanten - voer - voedingsstoffen - ingrediënten - diervoedering - diervoeding - afvalwater - biogas - biomassa productie - teelt - biobased economy
The objective of this study was to perform a short literature survey to provide information about purifying manure effluents with duckweed with regard to varieties, cultivation, harvesting methods, utilization and valorisation of duckweed. The results of the study show that duckweed can be used to recuperate nutrients from manure effluents and that the concerning duckweed can be utilized as a source of feed, energy and ingredients
Fungal treatment of lignocellulosic biomass
Kuijk, S.J.A. van - \ 2016
Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): John Cone; Anton Sonnenberg. - Wageningen : Wageningen University - ISBN 9789462576544 - 191
lignocellulosic wastes - fungi - treatment - ruminant feeding - rumen digestion - wheat straw - wood chips - livestock feeding - nutrition physiology - animal nutrition - lignocellulosehoudend afval - schimmels - behandeling - herkauwersvoeding - pensvertering - tarwestro - houtspaanders - veevoeding - voedingsfysiologie - diervoeding

Summary PhD thesis Sandra J.A. van Kuijk

Carbohydrates in plant cell walls are highly fermentable and could be used as a source for ruminant nutrition or biofuel production. The presence of lignin in cell walls hampers the utilization of these carbohydrates and should thus be removed. In this thesis, the possibilities of a fungal treatment of lignocellulosic biomass are investigated.

A review of the scientific literature focusing on the potential of fungal treatments to increase the utilization of lignocellulosic biomass in ruminants feed ingredients is presented in Chapter 2. A prerequisite to the effective use of high lignocellulose feed ingredients is lignin removal, since lignin is negatively correlated to in vitro rumen degradability. Selective lignin degrading fungi have proven to increase in vitro rumen degradability with Ceriporiopsis subvermispora and Pleurotus eryngii showing the greatest potential. The effectiveness of fungal treatment is not only dependent on the choice of fungal strain, but also on the choice of substrate and culture conditions.

Based on the literature review, four different edible fungal species, i.e. Ganoderma lucidum, Lentinula edodes, P. eryngii and P. ostreatus were chosen to treat four different substrates, i.e. miscanthus, rice straw, wheat straw and wood chips. The results of these fungal-substrate combinations are described in Chapter 3 and confirm that fungal species, substrate and incubation time are important factors in fungal treatment. The most promising fungus-substrate combinations are L. edodes treatment of wheat straw and L. edodes treatment of wood chips. These two fungus-substrate combinations were used in a more detailed characterization of changes in lignin upon fungal treatment.

In Chapter 4, a study is described where L. edodes treated wheat straw and wood chips are analyzed by pyrolysis coupled to gas chromatography and mass spectrometry (Py-GC/MS) confirming the selective lignin degradation as determined with the detergent fiber analysis. Structural changes in lignin were observed with preferential degradation of syringyl (S) lignin units over guaiacyl (G) lignin units by L. edodes. Upon fungal delignification, a number of degradation products of lignin were observed. The building blocks in the original lignin consist of phenolic groups with 3 C-atoms in the side chain, while degradation products consist of phenolic groups with 0 to 2 C-atoms in the side chain. The ratio between side chain degradation products and original compounds was increasing in both wheat straw and wood chips upon L. edodes treatment. Besides side chain degradation, L. edodes modified the Cα-atom of the side chain by oxidation. Although correlations were found, a clear relationship between lignin composition and in vitro rumen degradability could not be demonstrated.

The safety of a fungal treatment of ruminant feed ingredients requires the used fungus to have a Generally Regarded As Safe (GRAS) status. The literature data compiled in Chapter 2 indicates C. subvermispora, which does not have a GRAS status, as one of the most promising fungi for fungal treatment. For this reason this fungus was included in the remaining chapters. This fungus was researched in Chapter 5 with the substrates wheat straw and wood chips and compared to L. edodes. Both fungi selectively degraded lignin and improved in vitro rumen degradability and the amount of sugar released upon enzymatic saccharification. L. edodes continuously grew on wheat straw and wood chips while degrading lignin and hemicellulose at the same time. C. subvermispora colonized the wheat straw within the first week of treatment and starts degrading lignin and hemicellulose thereafter. Growth continued again after 5 weeks, which was accompanied by cellulose degradation. On wood chips, C. subvermispora stopped growing after the first week of treatment, while lignin degradation continued until 4 weeks of treatment. From 5 weeks onwards, no chemical changes were observed in wood chips. One of the explanations for this lack of change is the dense structure of the wood as observed with light microscopy. Both fungi degraded hemicellulose simultaneously with lignin. The loss of carbohydrates during fungal treatment and the long treatment times of up to 8 weeks represent a major disadvantage of fungal treatment of lignocellulosic biomass.

In Chapter 6, the incubation of C. subvermispora and L. edodes with wheat straw and wood chips were supplemented with urea to stimulate growth, and manganese and linoleic acid to stimulate lignin degradation via the enzyme manganese peroxidase produced by the fungi. Addition of manganese increased the selectivity of C. subvermispora treatment of wheat straw within the first 4 weeks of treatment. Addition of 150 µg manganese per g substrate improved lignin degradation and in vitro rumen degradability the most. A combination of manganese and linoleic acid did not show synergistic effects.

In Chapter 7 the particle size of wheat straw and wood chips, and the amount of C. subvermispora or L. edodes at the start of the treatment was varied. The amount of fungus added at the start of the treatment did not have an effect on colonization rate, lignin degradation or in vitro rumen degradability. L. edodes treatment of wheat straw chopped to 2 cm particles resulted in a higher lignin degradation and in vitro rumen degradability compared to L. edodes treatment of wheat straw chopped to a length of 0.5 cm. The particle size of wood chips did not have an effect on C. subvermispora treatment. In C. subvermispora treated wheat straw and L. edodes treated wood chips, a reduced growth was observed, which was unexpected based on results from previous experiments. A toxic compound to fungi (fungicide) was identified.

This thesis describes the potential of fungal treatment to increase utilization of lignocellulosic biomass. Fungal treatment resulted in an increased in vitro rumen degradability, and thus an increased cellulose accessibility. The same theory applies for biofuel production in which fungal treatment results in an increased accessibility of cellulose for enzymes. The major disadvantages of this low cost, relatively simple and environmentally-friendly biotechnological treatment are the loss of carbohydrates during the relatively long process of fungal incubation. Future studies should focus on optimization of the fungal treatment to enable large scale application.

Voer en water tijdens transport van pluimvee
Niekerk, T.G.C.M. van; Voogt, Annika ; Visser, E.K. - \ 2015
Wageningen UR Livestock Research (Livestock Research rapport 752) - 45
pluimvee - veevervoer - drinkwater - pluimveevoeding - diervoeding - dierenwelzijn - wetgeving - europese unie - dierlijke productie - diergezondheid - poultry - transport of animals - drinking water - poultry feeding - animal nutrition - animal welfare - legislation - european union - animal production - animal health
Handleiding Certificeerbare Eenheid Herpeten : nadere invulling benodigde kennis en vaardigheden : november 2015
Bras, R.J. ; Kuperus, S. ; Rossem, R. van; Ruis, M.A.W. - \ 2015
Wageningen : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 895) - 50
dierenwelzijn - reptielen - amphibia - gezelschapsdieren - diergezondheid - huisvesting, dieren - diervoeding - diergedrag - animal welfare - reptiles - amphibia - pets - animal health - animal housing - animal nutrition - animal behaviour
Zeker de laatste jaren is er veel veranderd in de manier waarop we dieren willen houden, simpelweg door de toename van kennis. Ook het welzijn van dieren is hierbij een steeds grotere rol gaan innemen. Om te bepalen wat welzijn inhoudt en welke kennis nodig is bij het houden van dieren is de wetgeving aangepast. Er worden nu een aantal eisen gesteld, samengevat in de zogenoemde vakbekwaamheid. Deze vakbekwaamheid moet gaan waarborgen dat enkel opgeleide mensen dieren kunnen, en mogen verhandelen. Zowel de kennisoverdracht als het vertrouwen in dierenspeciaalzaken en andere verkooppunten zal hiermee toenemen. In het traject naar vakbekwaamheid is een document als deze onmisbaar, het geeft de garantie dat ‘vakbekwaamheid’ inhoud heeft en overal hetzelfde betekent.
Replacing lactose from calf milk replacers : effects on digestion and post-absorptive metabolism
Gilbert, M.S. - \ 2015
Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Walter Gerrits; Henk Schols. - Wageningen : Wageningen University - ISBN 9789462576032 - 171
vleeskalveren - lactose - kunstmelk - polysacchariden - glucose - fructose - glycerol - zetmeelvertering - metabolisme - fermentatie - kalvervoeding - diervoeding - voedingsfysiologie - veal calves - lactose - filled milk - polysaccharides - glucose - fructose - glycerol - starch digestion - metabolism - fermentation - calf feeding - animal nutrition - nutrition physiology

Summary PhD thesis Myrthe S. Gilbert

Replacing lactose from calf milk replacers – Effects on digestion and post-absorptive metabolism

Veal calves are fed milk replacer (MR) and solid feed. The largest part of the energy provided to veal calves originates from the MR. Calf MR contains 40 to 50% lactose, originating from whey, a by-product from cheese production. High and strongly fluctuating dairy prices are a major economic incentive to replace lactose from the calf MR by alternative energy sources. The objective of this thesis was to study the effects of replacing lactose from calf MR on nutrient digestion and fermentation and post-absorptive metabolism.

In Chapter 2 and 3, four starch products (SP) were evaluated for replacing lactose. The four SP differed in size and branching, and consequently required different ratios of starch-degrading enzymes for their complete hydrolysis to glucose. Gelatinized starch required α-amylase and (iso)maltase; maltodextrin required (iso)maltase and α-amylase; maltodextrin with α-1,6-branching required isomaltase, maltase and α-amylase and maltose required maltase. In Chapter 2, adaptation to these SP was assessed during 14 weeks, using a within-animal titration study. Forty male Holstein-Friesian calves (n = 8 per treatment) were assigned to either a lactose control MR or one of four titration strategies, each testing the stepwise exchange of lactose for one of the SP. For control calves, fecal dry matter (DM) content and fecal pH did not change over time. The response in fecal DM content and fecal pH in time did not differ between SP treatments and decreased linearly with 0.57% and 0.32 per week, respectively, where one week corresponded to an increase in SP inclusion of 3%. This indicates that the capacity for starch digestion was already exceeded at low inclusion levels, resulting in SP fermentation. All SP required maltase to achieve complete hydrolysis to glucose and it was, therefore, suggested that maltase is the rate-limiting enzyme in starch digestion in milk-fed calves.

Following the titration, a fixed inclusion level of 18% of the SP in the MR was applied. Effects on starch-degrading enzyme activity, nutrient disappearance, SP fermentation and jugular glucose appearance were measured (Chapter 3). Lactase activity in the brush border was high in the proximal small intestine of all calves, resulting in a high apparent ileal disappearance of lactose (≥ 99% of intake). Maltase and isomaltase activities in the brush border were not increased for any of the SP treatments. Luminal α-amylase activity was lower in the proximal small intestine but greater in the distal small intestine of SP-fed calves compared to control calves. This amylase activity in the distal small intestine of SP-fed calves might have been of microbial origin. Apparent SP disappearance did not differ between SP treatments. The difference between apparent ileal (62%) and total tract (99%) SP disappearance indicated substantial SP fermentation in the large intestine (37% of intake). In addition, total tract SP fermentation was quantified using fecal 13C excretion which originated from the naturally 13C-enriched corn SP. Total tract SP fermentation averaged 89% of intake, regardless of SP treatment. MR leaking into the reticulorumen was measured as the recovery of Cr in the reticulorumen at slaughter after feeding MR pulse-dosed with Cr 4h prior to slaughter. MR leaking into the reticulorumen averaged 11% for SP-fed calves. By difference, this leaves 41% of the SP intake fermented in the small intestine. This coincided with increased fecal nitrogen (N) and DM losses for SP-fed calves. However, apparent total tract crude fat disappearance tended to increase when replacing lactose with SP. The substantial SP fermentation indicates that only 10% of the SP intake was enzymatically hydrolyzed and absorbed as glucose. This was in agreement with the marginal increase in 13C enrichment in peripheral plasma glucose after feeding naturally 13C-enriched gelatinized starch and maltose, compared to a clear increase after feeding naturally 13C-enriched lactose to control calves. It was concluded that fermentation, rather than enzymatic digestion, is the main reason for small intestinal starch disappearance in milk-fed calves. The expected decrease in growth performance with such extensive SP fermentation is partially compensated by the greater crude fat digestion and possibly by a reduced urinary glucose excretion when replacing lactose with SP.

Glucose, fructose and glycerol do not require enzymatic hydrolysis and can be absorbed directly from the small intestine. However, these lactose replacers might differentially affect glucose and insulin metabolism and with that energy partitioning. The effects of partly replacing lactose with glucose, fructose or glycerol on energy and N partitioning and glucose homeostasis and insulin sensitivity were, therefore, studied in Chapter 4 and 5. Forty male Holstein-Friesian calves either received a lactose control MR or a MR in which one third of the lactose was replaced with glucose, fructose or glycerol (n = 10 per treatment). Energy and N retention were not affected by MR composition. Fructose absorption from the small intestine was incomplete resulting in fructose fermentation. This resulted in fecal losses of DM, energy and N and the lowest numerical energy and N retention for fructose-fed calves. Postprandial plasma concentrations of glucose exceeded the renal threshold for glucose in glucose-fed calves and control calves, which resulted in urinary glucose excretion. Glycerol was likely excreted with the urine of glycerol-fed calves. Oxidation of glucose, fructose and glycerol was quantified by feeding a single dose of [U-13C]glucose, [U-13C]fructose or [U-13C]glycerol with the MR and subsequently measuring 13CO2 production. Oxidation of lactose replacers did not differ between lactose replacers and averaged 72% of intake. However, the time at which the maximum rate of oxidation was reached was delayed for fructose-fed compared to glucose-fed and glycerol-fed calves, indicating that fructose was converted into other substrates before being oxidized. Conversion of fructose and glycerol into glucose was confirmed by an increase in 13C enrichment of peripheral plasma glucose after feeding [U-13C]fructose and [U-13C]glycerol, respectively. Insulin sensitivity did not differ between MR treatments, but was already low at the start of the experiment at 15 weeks of age and remained low throughout the experiment. It was concluded that glucose and glycerol can replace one third of the lactose from the calf MR, but that inclusion of fructose should be lower to prevent incomplete absorption from the small intestine.

In literature and the studies in this thesis, high inter-individual variation in growth performance was found in veal calves. The experiment described in Chapter 6 was, therefore, designed to assess the predictability of later life growth performance by charactering calves in early life. In addition, it was examined whether the ability of calves to cope with MR in which lactose is partially replaced by alternative energy sources can be predicted. From 2 to 11 weeks of age, male Holstein-Friesian calves were fed a lactose control MR and solid feed according to a practical feeding scheme and were characterized individually using targeted challenges related to feeding motivation, digestion, post-absorptive metabolism, immunology, behavior and stress. Based on the results in Chapter 4, a combination of glucose, fructose and glycerol in a 2:1:2 ratio was used to replace half of the lactose from the MR (GFG). From 11 to 27 weeks of age, calves received a lactose control MR or the GFG MR (n = 65 per treatment). Growth performance from 11 to 27 weeks of age tended to be lower for GFG-fed than for control calves (-25 g/d). Measurements in early life explained 12% of the variation in growth performance in later life. However, this was mainly related to variation in solid feed refusals. When growth performance was adjusted to equal solid feed intake, only 4% of the variation in standardized growth performance in later life, reflecting feed efficiency, could be explained by early life measurements. This indicates that > 95% of the variation in feed efficiency in later life could not be explained by early life characterization. It is hypothesized that variation in health status explains substantial variation in feed efficiency in veal calves. Significant relations between fasting plasma glucose concentrations, fecal dry matter and fecal pH in early life and feed efficiency in later life depended on MR composition. These measurements are, therefore, potential tools for screening calves in early life on their ability to cope with a MR in which half of the lactose is replaced by glucose, fructose and glycerol (in a 2:1:2 ratio).

The studies reported in this thesis demonstrate that glycerol, glucose and a combination of glucose, fructose and glycerol in a 2:1:2 ratio are promising lactose replacers. The effects of replacing lactose by other carbohydrate or energy sources described in this thesis are required to evaluate the potential of lactose replacers for inclusion in calf milk replacers and provide input for feed evaluation for calves and ruminants.

Phosphorus metabolism in dairy cattle : literature study on recent developments and gaps in knowledge
Goselink, R.M.A. ; Klop, G. ; Dijkstra, J. ; Bannink, A. - \ 2015
Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 910) - 36
dairy cattle - phosphorus - nutrient requirements - animal nutrition - metabolism - melkvee - fosfor - voedingsstoffenbehoeften - diervoeding - metabolisme
Goal of this literature study is to define the uncertainties related to P requirement models and ways to make them more precise and more reliable than current systems and to find biomarkers to monitor P balance in living animals. Milk P is an important factor in P balance, and concentration may vary between individual cows. Bone represents a large P reserve and can have a profound impact on cow P balance and plasma P regulation. Plasma P concentration is still the most commonly used diagnostic measurement available to judge the P status of an animal, with all restrictions for good interpretation; new biomarkers defining P status are needed. Further research into mechanisms and quantification of the is needed to improve our understanding of P metabolism.
Rumen by-pass copper = Koper voorbij de Pens
Goselink, R.M.A. - \ 2015
Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 905) - 22
herkauwers - koper - verteringsabsorptie - pens - pensfermentatie - spijsvertering - voedingsfysiologie - diervoeding - ruminants - copper - digestive absorption - rumen - rumen fermentation - digestion - nutrition physiology - animal nutrition
De absorptie van koper (Cu) bij herkauwers is relatief laag vanwege de interacties tussen Cu en andere bestanddelen van het rantsoen, waardoor onoplosbare complexen gevormd worden die niet worden geabsorbeerd in de dunne darm. Dit kan mogelijk verbeterd worden door pensbestendige Cu bronnen aan te bieden, waardoor de Cu uitscheiding via de mest naar het milieu verminderd kan worden. Het doel van dit project was het evalueren van het effect van pensbestendige Cu bronnen op de Cu absorptie bij herkauwers. Dit is onderzocht met behulp van een in vitro model waarbij verschillende Cu bronnen zijn geïncubeerd om de fermentatie- en verteringsprocessen in het maagdarmkanaal te simuleren. Daarna is een proef uitgevoerd met 18 vleeskalveren waarbij twee pensbestendige Cu bronnen zijn vergeleken met kopersulfaat als controle. Het verschil in Cu absorptie tussen pensbestendige Cu bronnen en kopersulfaat was echter onvoldoende om in deze beperkte proefopzet aangetoond te kunnen worden.
Low emission feed : opportunities to mitigate enteric methane production of dairy cows
Hatew, B. - \ 2015
Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Jan Dijkstra; Andre Bannink; Wilbert Pellikaan. - Wageningen : Wageningen University - ISBN 9789462574458 - 228
melkkoeien - rundveevoeding - methaanproductie - milieueffect - pensfermentatie - voer - zetmeel - maïskuilvoer - graskuilvoer - diervoeding - dairy cows - cattle feeding - methane production - environmental impact - rumen fermentation - feeds - starch - maize silage - grass silage - animal nutrition

As global demand for high-quality food originating from animal production is expected to rise due to an increasing human population and consumer income level, the expected role of ruminants in meeting this demand brings multiple challenges. Ruminant production needs to adapt to environmental changes and, at the same time, reduce its impact on the environment. Ruminants production systems have a major impact on the environment through the emission of greenhouse gases such as methane (CH4), nitrous oxide and carbon dioxide. Microbial fermentation of feeds in the gastrointestinal tract, known as enteric fermentation, is the main source of CH4 emissions from dairy production. Enteric CH4 emission is strongly related to the amount of feed fermented in the rumen, which depends on feed intake, feed composition and rumen fermentation conditions associated to the intrinsic characteristics of these feeds and the characteristics of the whole diet. Important gaps in knowledge remain however. The prime aim of this thesis was to investigate the effects of various feeding strategies to mitigate enteric CH4 emissions of dairy cows.

First experiment was conducted to investigate the effects of type and level of starch in the concentrate. Inclusion of a high level (53%) of starch in the concentrate that accounted for 40% of the total mixed ration dry matter (DM) produced lower CH4 per unit of estimated rumen fermentable organic matter (eRFOM) than a low level (27% of DM) of starch (43.1 vs. 46.9 g/kg of eRFOM). Methane production per kg of eRFOM also was lower for diets based on rapidly fermentable starch (gelatinized maize grain) compared to diets based on slowly fermentable starch (native maize grain) (42.6 vs. 47.4 g/kg of eRFOM). However, inclusion of 53% of starch in the concentrate from both types of starch did not affect CH4 emission intensity (CH4 Ei) (CH4 emission per kg of fat- and protein-corrected milk; FPCM). In a subsequent experiment, maize silage was prepared from whole-plant maize harvested at a very early (25% DM), early (28% DM), medium (32% DM) and late (40% DM) stage of maturity and fed to dairy cows as an alternative to concentrate as starch source. Diet consisted of (on DM basis) 75% maize silage, 20% concentrate and 5% wheat straw. Increasing harvest maturity of maize silage linearly decreased CH4 yield (21.7, 23.0, 21.0 and 20.1 g/kg of DM intake) and CH4 emission as a fraction of gross energy intake (6.3, 6.7, 6.3 and 6.0%). Methane Ei tended to decrease linearly with maturity (13.0, 13.4, 13.2 and 12.1 g/kg FPCM). In another experiment grass silage as roughage source was tested. This experiment was designed to investigate the effects of N fertilisation of grassland and maturity of grass at cutting on CH4 emission in dairy cows. Two N fertilisation rates (65 vs. 150 kg of N/ha) were examined in combination with three stages of grass maturity (early, 28 days of regrowth; mid, 41 days of regrowth; and late, 62 days of regrowth). Diet contained 80:20 ratio (on DM basis) of grass silage (mainly ryegrass) and concentrate. Dry matter intake decreased with N fertilisation and maturity, and FPCM decreased with maturity but was unaffected by N fertilisation. Methane Ei (mean 15.0 g/kg of FPCM) increased by 31% and CH4 per unit digestible OM intake (mean 33.1 g/kg of DOMI) increased by 15% with increasing maturity. Methane yield (mean 23.5 g/kg of DM intake) and CH4 as a fraction of gross energy intake (mean 7%) increased by 7 and 9% with maturity, respectively, which implies an increased loss of dietary energy with progressing grass maturity. Rate of N fertilisation had no effect on CH4 Ei and CH4 yield.

Despite the importance of in vitro gas production technique for evaluating feeds, in vitro study as a stand-alone approach was considered inadequate to fully evaluate the potential effect of feeds and rumen fermentation modifiers on CH4 production, because in vitro studies are frequently performed separately rather than in parallel with in vivo studies. To test this hypothesis, both in vitro and in vivo CH4 measurements were measured simultaneously using cows in the first experiment that were fed (and adapted to) the same dietary material used as a substrate for in vitro incubation, as donor for microbial inoculum. It was found that 24-h in vitro CH4 (mL/g of incubated organic matter) correlated well with in vivo CH4 when expressed per unit of eRFOM (R2 = 0.54), but not when expressed per unit of organic matter ingested (R2 = 0.04). In the same experiment, results showed that incubation of the same substrate with rumen inocula obtained from donor cows adapted to different diets produced a variable amount of CH4 suggesting that it is important to consider the diet of the donor animal when collecting rumen inocula for in vitro incubation. Even though the in vitro technique has limitations to represent in vivo conditions, it is useful for screening of large sets of animal feeds or feed additives to be used as a CH4 mitigation strategy. In this thesis, two in vitro experiments were conducted to examine the effects of variation in structural composition of condensed tannins (CT) in sainfoin accessions collected from across the world on CH4 production, and CT extracts obtained from a selected sainfoin accessions on CH4 production. Results revealed substantial variation among CT in their effect on in vitro CH4 production and this variation was attributed to differences in chemical structure of CT. Condensed tannins evaluated in this thesis showed to have potential to reduce in vitro CH4 production, but require further investigations to fully evaluate their in vivo effects.

In conclusion, results from the research work conducted in this thesis show that changes in the basal diet of dairy cows and in roughage production management can substantially reduce the amount of enteric CH4 produced and thereby influence the impact of dairy production on the environment.

Kruiden verdringen antibiotica
Wolkers, H. ; Groot, M.J. ; Kleerebezem, M. ; Rebel, J.M.J. - \ 2015
WageningenWorld (2015)2. - ISSN 2210-7908 - p. 34 - 39.
veehouderij - diergezondheid - geneeskrachtige kruiden - dierziektepreventie - natuurlijke producten - antibiotica - reductie - dierenwelzijn - varkens - pluimvee - rundvee - melkvee - diervoeding - dierlijke productie - livestock farming - animal health - herbal drugs - animal disease prevention - natural products - antibiotics - reduction - animal welfare - pigs - poultry - cattle - dairy cattle - animal nutrition - animal production
Vanwege beperking van het antibioticagebruik vallen veehouders steeds vaker terug op kruiden, bacteriedrankjes en andere natuurlijke middelen om dieren gezond te maken én te houden. Hoewel harde medische claims niet altijd voorhanden zijn, boeken boeren soms spectaculaire resultaten met natuurlijke preparaten.
Impact of health status on amino acid requirements of growing pigs : towards feeding strategies for farms differing in health status
Kampman-van de Hoek, E. - \ 2015
Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Walter Gerrits; Alfons Jansman. - Wageningen : Wageningen University - ISBN 9789462573437 - 184
varkens - afmesten - diergezondheid - aminozuren - voedingsstoffenbehoeften - voedingseiwit - aminozuurmetabolisme - stikstofretentie - immuniteitsreactie - immuunsysteem - varkensvoeding - diervoeding - pigs - finishing - animal health - amino acids - nutrient requirements - dietary protein - amino acid metabolism - nitrogen retention - immune response - immune system - pig feeding - animal nutrition

Abstract

There is large variation in the production performance of commercial growing-finishing pig farms. This variation even exists when pigs have a similar genetic background and fed similar diets. The health status is one of the major factors contributing to this large variation in pig performance, as activation of the immune system can decrease feed intake, body weight gain and increase nutrient utilisation for immune system functioning. As a consequence, amino acids (AA) are repartitioned from skeletal muscle deposition towards utilisation for immune system functioning. Current requirement estimates for growing-finishing pigs are formulated to maximize protein deposition for growth and do not take into account the increased utilization of AA for immune functioning as induced by health challenging conditions. This lack of knowledge hampers the ability of feed manufacturers to optimize diets and improve pig performance. The main objective of the present thesis was to quantify the effect of health status on AA requirements for body protein deposition and for immune system functioning of growing pigs.

A health status web was developed as a tool to categorize growing-finishing pig farms on the basis of their health status. The health status web can be of use for feed manufacturers to develop targeted strategies to accommodate the nutritional requirements of pigs belonging to particular groups of farms sharing a common health status. A dose-response technique was developed, which is a simple, accu­rate technique to quantitatively estimate changes in AA requirements of individual meal-fed pigs. Nevertheless, a minimum time period of 21 days is required for each individual, which makes the technique inappropriate for studying the effect of immune system activation on AA requirements. The combined measurements of whole body N retention, plasma irreversible loss rate (ILR, i.e. the amount of free AA that disappears per unit of time from the plasma pool for protein synthesis or oxidation), urea entry and appearance of 13C into plasma proteins, provided insight into the consequences of immune system activation on AA metabolism.

Pigs selected from a farm with a suboptimal health status had greater serum haptoglobin, lower serum albumin concentrations, and greater leukocyte counts in blood at the start of the experiment than pigs selected from a farm with a high health status, indicating a higher level of immune system activation. The occurrence of compensatory gain in pigs from a farm characterized as having a suboptimal health status proves, however, that it is difficult to maintain a contrast in health status, and that pigs can adapt quickly to a change in housing conditions. In the absence of effects on feed intake, health challenging conditions may affect performance due to alterations in post-absorptive AA metabolism, as also indicated by increased urinary N losses, and a tendency for a reduced N retention and a lower utilization of digestible N for N retention in pigs with a systemic inflammation, or by a reduction in faecal nutrient digestibility as indicated for dry matter and N in pigs from a farm with a suboptimal health status. The observed changes in protein and AA metabolism after immune stimulation imply that especially tryptophan may become limiting during immune system activation, whereas lysine becomes excessive. Furthermore, the utilization of methionine, tyrosine, and valine for immune system functioning seems to increase in pigs with a systemic lung inflammation. In addition, the dietary AA or protein supply was able to modulate the acute phase response pre- and post-challenge, stressing the importance of an adequate dietary AA supply for appropriate functioning of the immune system of growing-finishing pigs.

Before implementing targeted feeding strategies for farms sharing a common health status, future research should be conducted to study the possible beneficial effects of increasing the dietary supply of particularly tryptophan, methionine, tyrosine, and valine relative to lysine for immune system function and for body protein deposition in pigs from farms with a different health status.

Unlocking resources in savannas: how goats and other mixed feeders overcome the negative effects of tannins
Mkhize, N.R. - \ 2015
Wageningen University. Promotor(en): Herbert Prins, co-promotor(en): Fred de Boer; Ignas Heitkonig. - Wageningen : Wageningen University - ISBN 9789462574274 - 110
geiten - tanninen - diervoeding - diervoedering - savannen - afgrazen - graasduur - begrazing - dierfysiologie - plantensamenstelling - afrika - goats - tannins - animal nutrition - animal feeding - savannas - browsing - grazing time - grazing - animal physiology - plant composition - africa

Abstract

This thesis contributes insights on how condensed tannins might mediate the interactions between woody plants and large herbivores in the African savannas. Current understanding in this regard is still based on data from short-term laboratory experiments, mostly with confined animals and a few correlative field studies that only explore relationships between tannin concentrations of plants with their intake. Although these experiments are a necessary first step in isolating and characterising the effects of condensed tannins, they oversimplify the complex interactions that occur between wild herbivores or livestock and plants. The challenge for research is to translate the roles of tannins in plant-herbivore interactions from controlled experiments to field conditions. The aims of this research were: to (1) investigate how condensed tannins influence foraging behaviour and growth performance of free-ranging ruminant herbivores, and (2) determine the effects of supplements on use of woody plants and intake rates of condensed tannins by free-ranging herbivores in a semi-arid savanna.

Field experiments were conducted and data collected on free-ranging goats as models for all mixed feeders that share similar characteristics with goats. Condensed tannin exposure levels to goats were experimentally increased in the field by orally dosing 15 goats with 20g condensed tannin powder extracted from a bark of tannin-rich species. To reduce tannin exposure, 15 goats were dosed with 20 g of PEG in an attempt to neutralize tannin effects, and another group of 15 goats was dosed only with water and served as a control group. Feeding behaviour of goats supplemented with a protein-rich source, an energy-rich source were compared with that of goats that were not supplemented.

The results indicated that mixed feeders exposed to high levels of condensed tannins spend more time grazing and less time browsing compared to animals with low tannin exposure. However, the findings did not support expectation for tannins to reduce overall foraging time. Therefore, it was concluded that condensed tannins do not necessarily suppress foraging, but only influence the amount of time animals spend foraging on either herbaceous or woody forage. These findings also supported hypothesis that herbivores forage in ways that minimize their intake rate of condensed tannins. Animals altered their foraging behaviour depending on the treatment groups they were allocated to, and compiled diets that indicated tannin minimization as a goal. Moreover, there was support for the notion that condensed tannins are digestibility reducers. It was clear that free-ranging animals are able to employ their behavioural adaptations to chemical defences in ways that mitigate the negative physiological effects on their presumed ultimate fitness. This thesis presents possible effects of nutrient-tannin/toxin interactions on herbivores in African savannas. In the supplementation experiment, proteins and energy equally increased browse consumption by herbivores, with a concomitant increase in tannin intake rates.

These results were explained in light of the ongoing bush encroachment in the African savannas. The expected increase in the availability of browse will probably impose a selection pressure for herbivores that can better utilise the encroaching woody plants known to be endowed with tannins and other carbon-based secondary metabolites. These results are used to generalise about the herbivore health, herbivore nutritional, and environmental benefits that are possible from managing our rangelands and herbivores in ways that increase utilization of chemically defended plants. For example, increased consumption of tannin-rich forage will not only improve nutrition, but it will also reduce internal parasite burden, and reduce bloating by ruminant herbivores while simultaneously reducing the methane emissions that lead to global warming.

Nutritional value of browse species most fed to zoo animals
Huisman, T.J. ; Hokwerda, J. - \ 2015
dierenwelzijn - dierentuindieren - diervoeding - diergezondheid - planten - voedingswaarde - begraasbare planten of plantendelen - animal welfare - zoo animals - animal nutrition - animal health - plants - nutritive value - browse
Poster met voedingswaarde van begraasbare planten voor dierentuindieren.
Body composition and reproduction in broiler breeders: impact of feeding strategies
Emous, R.A. van - \ 2015
Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Rene Kwakkel; Marinus van Krimpen. - Wageningen : Wageningen University - ISBN 9789462572386 - 173
vleeskuikenouderdieren - vleeskuikens - lichaamssamenstelling - gevogeltevoeding - voer - voedingseiwit - voeropname - diergedrag - corticosteron - voortplanting - vrouwelijke vruchtbaarheid - prestatieniveau - diervoeding - broiler breeders - broilers - body composition - fowl feeding - feeds - dietary protein - feed intake - animal behaviour - corticosterone - reproduction - female fertility - performance - animal nutrition

ABSTRACT

Key words: broiler breeder, feeding strategies, body composition, reproduction, behavior

Nowadays, welfare issues in broiler breeders associated with nutrition and reproductive characteristics, are becoming increasingly challenging. Due to genetic selection on broilers, body composition of breeders has changed dramatically during the last 50 years to less fat and more breast muscle. It is postulated that a certain amount of body fat in broiler breeders at the onset of lay is necessary for maximum performance and offspring quality. Body composition of breeders can be influenced by different feed allowances during rearing and lay, as well as by changes in nutrient composition of the diet. However, little is known about the effects of body composition on reproduction of broiler breeders. In this thesis, we investigated the effects of different feeding strategies during the rearing period on body composition at the end of rearing. Moreover, the effects of differences in body composition at the end of rearing, and feeding strategies during lay were evaluated on breeder performance, incubation traits, offspring performance, behavior and feather cover. From this study, it can be concluded that feeding a low protein diet during rearing decreased breast muscle and increased abdominal fat pad, whereas providing an increased feeding schedule, which resulted in a high growth pattern, only increased abdominal fat pad, at the end of rearing. The higher abdominal fat pad content resulted in an increased hatchability during the first phase of lay and a larger number of eggs during the second phase of lay. For maintaining growth pattern, broiler breeders had to provide a higher amount of feed with an increased energy to protein ratio compared to broiler breeders that were fed a diet with a standard energy to protein ratio. This resulted in an increased eating time and less stereotypic object pecking, which may indicate a reduced hunger and frustration. On the other hand, a low daily protein intake during the rearing and first phase of lay can lead to a poor feather cover. Feeding a high-energy diet during the second phase of lay resulted in increased hatchability, decreased embryonic mortality and more first grade chicks.

Insecten als grondstof voor voer. In Zuid-Afrika werkt het bedrijf Agriprotein als eerste aan de productie van maden op industriële schaal. : Insectencentrum Lelystad
PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2015
Boerderij 100 (2015)18. - ISSN 0006-5617 - p. 20 - 20.
insecten als voedsel - voer van dierlijke oorsprong - voer - diervoeding - insects as food - feed of animal origin - feeds - animal nutrition
Insecten als grondstof voor voer. In Zuid-Afrika werkt het bedrijf Agriprotein als eerste aan de productie van maden op industriële schaal.
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