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.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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In vitro studie naar de invloed van intrinsiek en microbieel fytase op de afbraak van fytinezuur in biologische geteelde grondstoffen voor de dierhouderij : Een verkennende studie
Jonge, L.H. ; Wikselaar, P.G. van; Bikker, P. ; Krimpen, M.M. van - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1006) - 25
fytase - fytinezuur - biologische landbouw - veevoeder - voer - varkenshouderij - pluimveehouderij - ruwe grondstoffen - fosfaat - phytase - phytic acid - organic farming - fodder - feeds - pig farming - poultry farming - raw materials - phosphate
In this study, the usefulness of intrinsic phytase of plant ingredients for degrading phytate was investigated. The enzymatic conversion from phytate to soluble inorganic phosphate was determined in vitro with and without addition of microbial phytase. Phytate degradation was measured in mixtures in which ingredients with a high intrinsic phytase activity and ingredients with a high phytate content were combined.
Nutrition of pigs kept under low and high sanitary conditions : effects on animo acid and energy metabolism and damaging behaviour
Meer, Yvonne van der - \ 2017
University. Promotor(en): Walter Gerrits, co-promotor(en): Alfons Jansman; Aart Lammers. - Wageningen : Wageningen University - ISBN 9789463431972 - 181
pigs - feeds - pig feeding - animal nutrition - amino acid metabolism - animal health - energy metabolism - abnormal behaviour - behaviour disorders - immune system - nutrition physiology - varkens - voer - varkensvoeding - diervoeding - aminozuurmetabolisme - diergezondheid - energiemetabolisme - abnormaal gedrag - gedragsstoornissen - immuunsysteem - voedingsfysiologie

It is economically and environmentally important to match the nutrient supply to the nutrient requirements in pig production. Until now, the effects of different sanitary conditions on energy and nutrient requirements are not implemented in recommendations for nutrient composition of pig diets. The current nutrient requirement data are based on studies with pigs in experimental settings, which can be regarded as rather optimal. Changes in nutrient requirements caused by differences in sanitary conditions are poorly documented. As in the pig production sector farm conditions are variable it is of major importance to determine the effects of low sanitary conditions (LSC) on requirements for amino acids and energy in growing pigs. Pigs under LSC have an increased risk of clinical and subclinical infections, resulting in a chronic stimulation of their immune system. Immune system stimulation is known to influence energy and amino acid metabolism. However, most studies in pigs evaluating the relationship between immune system stimulation and nutrient requirements often use specific experimental challenge models. Whereas such models have the obvious advantage of reproducibility and allow mechanistic insight in the effects of stimulating specific parts of the immune system, these models often induce clinical illness, rather than subclinical infections. Results obtained with such models may therefore be difficult to translate to practical situations. Therefore the objective of the present thesis was to study the effect of low and high sanitary conditions (HSC) on amino acids and energy metabolism in pigs. Also interactions between the immune system, nutrient metabolism and damaging behaviour of pigs were considered in this thesis.

The experiment described in Chapter 2 was designed to study the effect of different dietary crude protein levels and extra amino acid supplementation on the growth performance of pigs kept under different sanitary conditions. In a 2×2×2 factorial arrangement, 68 groups of 9 pigs were allocated to either LSC or HSC, and were offered ad libitum access to two different diets, a normal crude protein concentration diet or a low crude protein concentration diet, each having either a basal dietary amino acid profile or supplemented dietary amino acid profile containing 20% more methionine, threonine, and tryptophan compared with the basal profile. The pigs were followed from 10 weeks of age until slaughter. Haptoglobin concentrations in serum and IgG antibody titers against keyhole limpet heamocyanin, collected in the starter, grower, and finisher phases, and pleuritis scores at slaughter were greater for LSC pigs compared with HSC pigs, illustrating that sanitary conditions affected health conditions. The average daily gain and gain to feed ratio were greater for HSC pigs compared with LSC pigs. A 20% increase in dietary supplementation of methionine, threonine, and tryptophan relative to lysine increased gain to feed ratio more in LSC than in HSC pigs. The results therefore illustrated that dietary requirements for methionine. threonine, and tryptophan were greater for LSC compared with HSC pigs.

In Chapter 3 the damaging behaviour of 576 pigs from the experiment in Chapter 2 was evaluated. At 15, 18, and 24 weeks of age, prevalence of tail and ear damage, and of tail and ear wounds was scored. At 20 and 23 weeks of age, frequencies of biting behaviour and aggression were scored by behaviour sampling. The prevalence of ear damage during the finisher phase and the frequency of ear biting were increased in LSC compared with HSC pigs. The frequency of ear biting was increased in low protein fed pigs compared with normal protein fed pigs. The supplemented AA profile reduced ear biting only in LSC pigs. The prevalence of tail wounds was lower for pigs in LSC than for pigs in HSC in the grower phase. Regardless of dietary amino acid profile or sanitary status, pigs fed low protein diets showed more ear biting, tail biting, belly nosing, other oral manipulation directed at pen mates, and aggression than pigs fed normal protein diets, with no effect on ear or tail damage. In conclusion, both LSC and a reduction of dietary protein increased the occurrence of damaging behaviours in pigs and therefore may negatively impact pig welfare.

The experiment of Chapter 4 was designed to quantify the difference in energy requirements for maintenance, and in incremental efficiencies for deposition of dietary energy and protein in the body of clinically healthy pigs kept under LSC or HSC, fed a basal diet either or not supplemented with additional methionine, threonine and tryptophan.

In a 2 × 2 factorial arrangement, 24 groups of 6 pigs each were allocated to either a LSC or HSC, and were offered two different diets having either a basal or a dietary amino acid profile supplemented with methionine, threonine, and tryptophan. For each group of pigs, complete energy and nitrogen balances were determined during two consecutive weeks, during which feed was available ad libitum or at 70% of ad libitum. Fasting heat production was determined over a 25 h period of fasting after a period of restricted feeding. Low sanitary conditions increased fasting heat production from 696 to 750 kJ/(kg BW0.6 . d), regardless of the dietary amino acid supplementation. The incremental efficiency of ingested nitrogen for retention in the body was reduced in LSC pigs from 73 to 53%, but incremental efficiencies of digestible energy intake for fat deposition in the body were unaffected by the experimental treatments. These findings showed that the effects of continuous immune stimulation by introducing LSC, was affecting energy and nutrient efficiencies of pigs both at maintenance level and at a feeding level close to ad libitum intake.

In Chapter 5 diurnal patterns for heat production, respiratory quotient, and carbohydrate and fat oxidation of the pigs studied in the experiment of Chapter 4 were evaluated to get more insight in the mechanisms behind the effects found in Chapter 4. The LSC pigs had reduced activity compared with HSC and a higher resting metabolic rate during the period of restricted feeding, especially during the light parts of the day. Therefore the diurnal energy expenditure pattern of LSC and HSC pigs can be considered as different. Fat and carbohydrate oxidation patterns were not different for LSC and HSC pigs, indicating that protein and fat deposition during the day was similar for LSC and HSC pigs.

Overall, the results of this thesis indicate that both energy and AA requirements are greater in LSC pigs compared with HSC pigs. It is questionable, however, whether it is nutrient and cost effective and biologically possible to satisfy these increased nutrient requirements in LSC pigs, as the incremental efficiency of N for retained protein is low, and ADFI is reduced for LSC pigs compared with HSC pigs. The present thesis demonstrates that care should be taken in reducing dietary protein concentrations to improve protein efficiency in pigs, as it incurs a risk to increased damaging behaviours, particularly when pigs are kept under LSC.

Interactions and functionalities of the gut revealed by computational approaches
Benis, Nirupama - \ 2017
University. Promotor(en): Mari Smits; Vitor Martins dos Santos, co-promotor(en): Dirkjan Schokker; Maria Suarez Diez. - Wageningen : Wageningen University - ISBN 9789463434546 - 247
pigs - mice - digestive tract - digestive system - intestinal microorganisms - intestinal mucosa - computational science - immune system - feeds - animal nutrition - nutrition physiology - animal health - varkens - muizen - spijsverteringskanaal - spijsverteringsstelsel - darmmicro-organismen - darmslijmvlies - immuunsysteem - voer - diervoeding - voedingsfysiologie - diergezondheid

The gastrointestinal tract is subject of much research for its role in an organism’s health owing to its role as gatekeeper. The tissue acts as a barrier to keep out harmful substances like pathogens and toxins while absorbing nutrients that arise from the digestion of dietary components in in the lumen. There is a large population of microbiota that plays an important role in the functioning of the gut. All these sub-systems of the gastrointestinal tract contribute to the normal functioning of the gut. Due to its various functionalities, the gut is able to respond to different types of stimuli and bring the system back to homeostasis after perturbations.

The work done in this thesis uses several bioinformatic tools to improve our understanding of the functioning of the gut. This was achieved with data from model animals, mice and pigs which were subjected to changing environments before their gastrointestinal response was measured. Different types of stimuli were studied (eg, antibiotic exposure, changing diets and infection with pathogens) in order to understand the response of the gut to varying environments. This data was analysed using different data integration techniques that provide a holistic view of the gut response.

Vertical data integration techniques look for associations between different types of ~omics data to highlight possible interactions between the measured variables. Lateral integration techniques allow the study of one type of ~omics data over several time points or several experimental conditions. Using these techniques, we show proof of interactions between different sub-systems of the gut and the functional plasticity of the gut. Of the several hypotheses generated in this thesis we have validated several using existing literature and one using an in-vitro system. Further validation of these hypotheses will increase understanding of the responses of the gut and the interactions involved.

Consequences of dry period length and dietary energy source on physiological health variables in dairy cows and calves
Mayasari, Nova - \ 2017
University. Promotor(en): Bas Kemp, co-promotor(en): Ariette van Knegsel; Henk Parmentier. - Wageningen : Wageningen University - ISBN 9789463431408 - 221
dairy cows - calves - dry period - feed rations - feeds - energy balance - animal health - inflammation - antibodies - adaptation physiology - immunology - melkkoeien - kalveren - gustperiode - voedingsrantsoenen - voer - energiebalans - diergezondheid - ontsteking - antilichamen - adaptatiefysiologie - immunologie

During the transition period, dairy cows experience a negative energy balance (NEB) caused by the high energy requirement for milk yield, while feed intake is limited. Severity of the NEB has been associated with an increased incidence of metabolic disorders and infectious diseases, inflammation, immunosuppression and oxidative stress. It is known that shortening or omitting the dry period or feeding a glucogenic ration improves the energy balance (EB) in dairy cows in early lactation. It can be expected that an improvement of the EB due to shortening or omitting the dry period results in reduced inflammation, immunosuppression and less oxidative stress in dairy cows in early lactation. The first objective of this thesis was to study the effects of dry period length and dietary energy source on immune competence, inflammatory biomarkers and oxidative stress in dairy cows over 2 subsequent lactations. The second objective was to study the consequences of maternal dry period length on colostrum immunoglobulin content and immune competence of calves in the first 12 weeks of life. In the current study, 167 cows were assigned to 3 dry period lengths (0, 30, or 60 d) and 2 early lactation rations (glucogenic or lipogenic). Cows were planned to have the same dry period length and ration over 2 subsequent lactations. Omitting the dry period reduced plasma bilirubin levels compared with a conventional dry period, which is line with the better EB in cows with a 0-d dry period. Effects of dry period length on inflammatory biomarkers, oxidative stress variables and natural antibodies (NAb) titers were, however, less consistent. Omitting the dry period increased not only negative acute phase proteins (APP) in plasma, but also positive APP, oxidative stress variables in plasma, and NAb in milk. Shortening the dry period to 30-d did not influence inflammatory biomarkers and oxidative stress compared with a conventional dry period of 60-d. Occurrence of clinical health problems did not differ between cows with different dry period lengths. In the current study, changes in positive APP and oxidative stress variables in plasma and NAb in milk could be explained by the occurrence of clinical health problems related to inflammation (clinical mastitis, fever, metritis and retained placenta), rather than a better EB due to a shorter or no dry period. Moreover, a higher titer of IgG binding lipopolysaccharide in plasma was associated with decreased odds of high somatic cell count and occurrence of clinical mastitis. In the first lactation after implementation of dry period length and dietary treatments, feeding a glucogenic ration in early lactation increased NAb titers in milk compared with a lipogenic ration, which could be explained partly by a better EB. In the second lactation after implementation of dry period length and dietary treatments, feeding a lipogenic ration in early lactation increased cholesterol levels in plasma compared with a glucogenic ration, which could be related to the high fat content in this ration. Cows with a 0-d dry period had a lower colostrum production and less immunoglobulins in colostrum compared with cows with a 30-d or 60-d dry period. After colostrum uptake, NAb titers in plasma of calves from cows with a 0-d dry period were lower during the first week of life compared with calves from cows with a 30-d or 60-d dry period. Levels of specific antibodies in calves, after immunization in week 6 and 10, in calves were not affected by the maternal dry period length. Birth weight of calves from cows with a 0-d dry period was lower compared with calves from cows with a 30-d dry period, but not compared with calves from cows with a 60-d dry period. Growth of calves until 12 weeks of life was not affected by dry period length. In conclusion, although shortening and omitting the dry period improved the EB in early lactation, this did not result in clear consistent effects of dry period length on inflammation or oxidative stress. Changes in inflammation biomarkers, oxidative stress variables and NAb in milk were a reflection of the occurrence of health problems related to inflammation in particular clinical mastitis and compromised uterine health. Furthermore, albeit omitting the dry period compared with shortening or conventional dry period cows resulted in a reduced immunoglobulin content in colostrum and reduced NAb titers in plasma of their calves in the first week of life, but did not affect specific immune response of the calves in the first 12 weeks of life.

Feeds, water quality, gut morphology and digestion in Nile tilapia (Oreochromis niloticus)
Trần Ngọc Thiên Kim, Kim - \ 2017
University. Promotor(en): Johan Verreth, co-promotor(en): Johan Schrama; Arjen Roem. - Wageningen : Wageningen University - ISBN 9789463431484 - 127
tilapia - oreochromis niloticus - feeds - fish feeding - water quality - digestion - digestibility - intestines - morphology - fish culture - aquaculture - voer - visvoeding - waterkwaliteit - spijsvertering - verteerbaarheid - darmen - morfologie - visteelt - aquacultuur

Diet composition, ingredient and nutrients, are important to consider for maintaining intestinal functions. Studies on both positive (using feed additives) and negative effects (using high inclusion of plant ingredients) of fish feeds are numerous, however, between studies results are often highly variable, both in type of response and in significance. The central hypothesis of this study was that adverse environmental conditions may aggravate negative effects of plant ingredients on the intestinal functions to the extent that mild effects become severe and perceptible. To do so, dietary factors and environmental conditions were evaluated and the interaction between diet composition and environmental conditions were studied in Nile tilapia.

In Chapter 2, six common raw materials including hydrolysed feather meal (HFM), soybean meal (SBM), rice bran (RB), rapeseed meal (RM), sunflower meal (SFM) and dried distiller grains with solubles (DDGS) were chosen to determine the effect of nutrient digestibility, nitrogen/energy balance and changes in intestinal morphology. The study demonstrated that feed ingredients do have an impact on the alteration in intestinal parameters, but also on the nutrient digestibility and the nitrogen/energy balance. Although being well digested, soybean meal caused the most obvious alteration in the intestinal morphology. These alterations were not related to the nutrient digestibility nor to nitrogen/energy balance parameters. Soybean meal, causing the most alterations in the intestinal morphology, was further used in all subsequent chapters of this thesis.

Chapter 3 and 4 described the interaction between diet composition and environmental conditions on the intestinal functions. This was studied with two different environmental conditions, dissolved oxygen (Chapter 3) and salinity (Chapter 4). These two chapters evaluated whether suboptimal environmental conditions (low dissolved oxygen or elevated salinity in water) may interact with a soybean meal based diet in nutrient digestion and intestinal morphology of tilapia. The study demonstrated that environmental stressors can aggravate/reveal the negative intestinal morphology changes induced by a soybean meal based diet. However, these effects of adverse environmental conditions on the intestinal functions were not homogenously dispersed over the whole intestinal length. The effect of salinity on the intestinal morphology occurred predominantly in the distal intestine, whereas the effect of low oxygen concentration was more visible at the proximal intestine. Alterations in the intestinal morphology, as found in this study, have wider effects on the performance of the affected fish. In Chapter 3, the protein digestibility decreased under hypoxic conditions at week 8, which parallels with the time related alteration in intestinal morphology. Chapter 4 showed that when fish were raised at 15 ‰ salinity, nutrient digestibility increased; however, this positive effect decreased when the intestinal morphology changed. The study also found that the combined effect of a soybean meal based diet and hypoxia was stronger compared to the combination with elevated salinity. Therefore, the combination with hypoxia was further used in the next study of this thesis.

In Chapter 5, the combination of hypoxic condition and a soybean meal based diet was chosen to test the hypothesis that only under stressful conditions, the effects of feed additives can be noticed. The impact of two dietary organic acids, formic acid and butyric acid, on nutrient digestibility and intestinal morphology was determined under optimal (normoxia) and suboptimal conditions (hypoxia). The results showed that although organic acids did not significantly improve growth performance and nutrient digestibility under normoxic condition, they did so under hypoxic conditions. Fish fed organic acid supplemented diets all showed improvements in the morphology of intestine under normoxic conditions, and these effects were more enhanced under hypoxic conditions. This indicates that environmental conditions can alter the effect of organic acid on nutrient digestibility and intestinal morphology in tilapia.

Finally, Chapter 6 provided a synthesis of the main findings, and a reflection on the methodologies used in Chapters 2-5 as well as a discussion on the relevance of this study to aquaculture. It is concluded that although being well digested, soybean meal caused the most obvious alteration in intestinal morphology. The adverse environmental conditions aggravated negative effects of soybean meal based diets on the intestinal functions to the extent that mild effects become severe and visible. The negative effect on intestinal morphology of soybean meal in the diet is enhanced at low oxygen level and at elevated salinity. The effect of salinity on the intestinal morphology occurs predominantly in the distal intestine, whereas the effect of low oxygen concentration is more visible at the proximal intestine. The thesis indicated that the impact of organic acids on intestinal functions is dependent on environmental conditions, being more pronounced under challenging conditions (e.g. hypoxia). Therefore, studies on both positive (using feed additives) and negative effects (using high inclusion of plant ingredients) of dietary factors should be done under suboptimal conditions.

KringloopToets: sluiten van de nutriëntenkringloop op het niveau van Noordwest-Europa : inhoudelijke en procesmatige rapportage
Leenstra, Ferry ; Vellinga, Theun ; Bremmer, Bart - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1019) - 47
nutriëntenstromen - voer - diervoedering - diervoeding - recycling - noordwest-europa - nutrient flows - feeds - animal feeding - animal nutrition - northwestern europe
The Nutrient Cycle Assessment aims at visualizing nutrient flows. In policy documents closing of nutrient cycles at the level of North Western Europe is often mentioned. Province North Brabant, farmers organisation ZLTO and NGO BMF examined together with Wageningen University & Research the effects of closing the borders of North West Europe (Benelux, France, Germany, UK) for feed ingredients and animal products. The results of this exercise were discussed in a separate session with representatives of the feed industry. This report describes the conclusions of the analysis and the lessons that can be learned from this exercise for future work with the Nutrient Cycle Assessment.
First week nutrition for broiler chickens : effects on growth, metabolic status, organ development, and carcass composition
Lamot, David - \ 2017
University. Promotor(en): Bas Kemp, co-promotor(en): Henry van den Brand; Peter Wijtten. - Wageningen : Wageningen University - ISBN 9789463430777 - 187
broilers - animal nutrition - poultry feeding - feeds - growth - metabolism - carcass composition - nutrition physiology - vleeskuikens - diervoeding - pluimveevoeding - voer - groei - metabolisme - karkassamenstelling - voedingsfysiologie

During the first week of life, broiler chickens undergo various developmental changes that are already initiated during incubation. Ongoing development of organs such as the gastro- intestinal tract and the immune system may affect the nutritional requirements during this age period. Despite the residual yolk that is available at hatch and that may provide nutritional support during the first days after hatch, the growth performance may be affected by the time in between hatch and first feed intake. Furthermore, it remains largely unknown to what extend nutritional composition of a pre-starter diet, as well as feed availability directly after hatch have an effect on physiological development directly after hatch, but also at later age. The aim of this thesis was to determine the impact of feed availability and feed composition provided during the first week of life on short-term physiological development, as well as potential long-term effects on growth performance of broiler chickens. Especially early hatched chickens were suggested to benefit more from direct feed access compared to midterm and late hatched chickens, as they tended to have a higher body weight gain during the first week after hatch. A delay in feed access for 48 h resulted in lowered body weight gain and feed intake when compared to direct feed access, but so did a short (13 to 26 h) delay in feed access after hatch. In the latter case, delayed feed access resulted in a lower weight to length ratio of the jejunum and ileum at 4 d of age compared with chickens with direct feed access. Although delayed feed access after hatch resulted in lower body weight gain during the first week after hatch and thereafter, it can be discussed whether this is truly an impairment of long-term growth or just a delayed onset of growth. With respect to feed composition, the inclusion of fish oil and medium chain fatty acids in a pre-starter diet had minor effects on humoral immune function. Inclusion of medium chain fatty acids did result in higher body weight gain and lowered feed efficiency during the first week of life, but only during the period it was provided. Feeding increased diet densities during the first week of life, obtained by formulating diets with different dietary fat levels, resulted in an increased gain to feed ratio, whereas body weight gain and feed intake decreased. Despite the shift in dietary energy supply from carbohydrates to fat and the perceived lower fat digestibility in young broiler chickens, nitrogen metabolizability and fat digestibility were not affected in the current study by feeding increased diet densities. The relative crop, liver and pancreas weights decreased when feeding increased diet densities, whereas the length of the entire intestinal tract increased. This suggests that broiler chickens repartition visceral organ development in response to feeding more concentrated diets during the first week of life. Interestingly, protein and fat accretion were not affected. Continued feeding of increased diet densities after 7 d of age resulted in increased BW gain, G:F ratio and metabolizable energy intake, but mainly during the periods that these diets were provided. In summary, even short durations of delayed feed access already impact intestinal development of young broiler chickens. However, a delayed feed access up to 48 h after hatch does not result in impaired growth, but only a delayed onset of growth. Even though digestibility of fats and oils may be suboptimal in young broiler chickens, feeding of these diets does not have to result in lowered performance per se. Young broiler chickens appear to adapt themselves towards high density diets with high fat inclusion levels in the first week of life, enabling them to digest and metabolize these diet types despite a suboptimal capacity for fat digestion. High density diets result in higher growth performance, but only for the period these diets are provided and thus carry-over effects at later age appear to be limited.

Verkenning regionale kringlopen : sluiten van nutriëntenkringloop op het niveau van Noordwest-Europa
Leenstra, Ferry ; Vellinga, Theun - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 987) - 34
voer - voedingsstoffen - dierlijke producten - kringlopen - dierhouderij - dierlijke meststoffen - noord-brabant - noordwest-europa - feeds - nutrients - animal products - cycling - animal husbandry - animal manures - northwestern europe
CVB Veevoedertabel 2016 : chemische samenstellingen en nutritionele waarden van voedermiddelen
Blok, M.C. ; Spek, J.W. - \ 2016
Netherlands : CVB - 629 p.
voedertabellen - voer - chemische samenstelling - voedingswaarde - diervoedering - diervoeding - feed composition tables - feeds - chemical composition - nutritive value - animal feeding - animal nutrition
Coproducten verwaarden
Keijsers, Edwin ; Duinkerken, Gert van - \ 2016
coproduction - food industry - residual streams - waste utilization - animal feeding - feeds - biobased economy - byproducts
Stel, je bent producent in de levensmiddelenindustrie. Van bijvoorbeeld de aardappels die je gebruikt voor chipsproductie blijft een deel ‘onbruikbaar’ product over. Gooi je het weg? Zonde, deze stromen kunnen interessant zijn voor de diervoederindustrie. In de afgelopen jaren is het gebruik van zogenoemde coproducten licht gestegen.
Protein quality of pig diets : processing effects on amino acid digestibility and post-absorptive utilization
Hulshof, Tetske - \ 2016
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.

Low Emission Feed : using feed additives to decrease methane production in dairy cows
Klop, G. - \ 2016
University. Promotor(en): Wouter Hendriks, co-promotor(en): Jan Dijkstra; Andre Bannink. - Wageningen : Wageningen University - ISBN 9789462578944 - 168 p.
feeds - emission - feed additives - dairy cows - methane production - nitrates - docosahexaenoic acid - milk composition - voer - emissie - voedertoevoegingen - melkkoeien - methaanproductie - nitraten - docosahexaeenzuur - melksamenstelling

Research into manipulating methane (CH4) production as a result of enteric fermentation in ruminants currently receives global interest. Using feed additives may be a feasible strategy to mitigate CH4 as they are supplied in such amounts that the basal diet composition will not be largely affected. The latter is relevant because ruminants have the capacity to convert human inedible feedstuffs into human edible energy and protein. However, the application of CH4 mitigation feed additives may be hampered by several negative side effects including trade-offs with other environmental impacts, negative effects on animal performance, and lack of persistency of the mitigating effect. The research described in this thesis addresses both the mitigating effect of feed additives as well as its persistency. The main focus was on investigating additivity of the CH4 mitigating effect of feed additives, on the adaptation of rumen microbes to long term feeding of feed additives, and on exploring the potential of rotational feeding of additives to avoid (or reduce) microbial adaptation.

In an experiment with lactating dairy cows in climate respiration chambers to study potential interactions between the effects of feeding nitrate and docosahexaenoic acid (DHA; C22:6 n-3) on enteric CH4 production, the effects of nitrate and DHA on CH4 yield [g/kg dry matter intake (DMI)] and CH4 intensity [g/kg fat- and protein- corrected milk (FPCM)], were additive (Chapter 2). Nitrate decreased CH4 irrespective of the unit in which it was expressed, and the average decline in CH4 emission corresponds to 85% of the stoichiometric potential of nitrate to decrease CH4. Feeding DHA had no effect on CH4 yield, but resulted in a higher CH4 intensity, because of milk fat depression. The interaction effect between nitrate and DHA on fiber digestibility indicated that negative effects of nitrate on apparent total tract digestibility of nutrients were alleviated by DHA, probably due to an altered feed intake pattern.

Using an isotope measurement protocol in the same study, it was demonstrated that effects of nitrate as a CH4 mitigating feed additive on fiber degradation in the rumen can be detected by evaluating diurnal patterns of 13C enrichment of exhaled CO2 (Chapter 3). Feeding nitrate, but not DHA, resulted in a pronounced increase in 13C enrichment of CO2 in the first 3 to 4 h after feeding only. Results support the hypothesis that effects of a feed additive on the rate of fiber degradation in the rumen can be detected by evaluating diurnal patterns of 13C enrichment of CO2. A prerequisite for this detection method is that the main ration components differ in natural 13C enrichment (e.g., C3 and C4 plants), and in content of the nutrients that are expected to be involved in a shift in fermentation (e.g., starch and fiber) or in degradability of a nutrient.

In a combined in vivo and in vitro trial, the adaptation to CH4 mitigating feed additives, viz. an essential oil blend or lauric acid (C12:0), compared with a control diet was first investigated using the in vitro gas production technique during the period that lactating cows were adapting to certain feed additives (Chapter 4). Rumen fluid was collected from each cow at several days relative to the introduction of the additives in the diets and used as inoculum for the gas production experiment with each of the three different substrates that reflected the treatment diets offered to the cows. The feed additives in the donor cow diet had a stronger effect on in vitro gas and CH4 production than the same additives in the incubation substrate. From day 4 onwards, the C12:0 diet persistently reduced gas and CH4 production, total volatile fatty acid concentration, acetate molar proportion and in vitro organic matter degradation, and increased propionate molar proportion. In contrast, in vitro CH4 production was reduced by the essential oils diet on day 8, but not on days 15 and 22. In line with these findings, the molar proportion of propionate in fermentation fluid was higher, and that of acetate smaller, for the essential oils diet than for the control diet on day 8, but not on days 15 and 22. Overall, the data indicate a transient effect of the essential oils on CH4 production, which may indicate microbial adaptation, whereas the CH4 mitigating effect of C12:0 persisted. It is recommended that this phenomenon is considered in the planning of future studies on the mitigation potential of feed additives in vitro.

In a follow-up in vivo study, it was investigated whether the alternate feeding of two CH4 mitigating feed additives with a different mode of action (viz. C12:0 and a blend of essential oils) would result in a persistently lower CH4 production compared to feeding a single additive over a period of 10 weeks. The experiment comprised a pre-treatment period and three two-week measurement periods, with two periods of 2 weeks in between in which CH4 emission was not measured. Cows received either continuously the essential oil blend, or both the essential oil blend and C12:0 following a weekly rotation schedule (Chapter 5). Both CH4 yield and CH4 intensity changed over time, but were not affected by treatment. Methane yield and intensity were significantly lower (12 and 11%, respectively) in period 1 compared with the pre-treatment period, but no significant difference relative to the pre-treatment period was observed in period 3 (numerically 9 and 7% lower, respectively) and in period 5 (numerically 8 and 4% lower, respectively). These results indicate a transient decrease in CH4 yield and intensity in time, but no improvement in extent or persistency of CH4 reduction due to rotational feeding of essential oils and C12:0 in lactating dairy cows. However, there were indications that the concept of rotation may be effective and warrants further investigation.

The additives and concepts tested in this thesis are applied under specific experimental conditions. More mechanistic understanding is required to predict the response of the same additives when supplemented to other basal diets or cows in a different physiological state. Trade-offs in environmental impact, and effects on cow health and performance, and on milk processing parameters and food safety are important aspects to consider in future research on the application of feed additives as CH4 mitigation strategy.

Innovaties bij ACRRES met aquatische biomassa
Weide, Rommie van der - \ 2016
waste water treatment - biomass production - aquatic biomass - pilot projects - test rigs - algae culture - applications - feeds - biobased economy
Feed sources for livestock : recycling towards a green planet
Zanten, H.H.E. van - \ 2016
University. Promotor(en): Imke de Boer, co-promotor(en): Paul Bikker; Bastiaan Meerburg. - Wageningen : Wageningen University - ISBN 9789462578050 - 251 p.
cum laude - livestock - livestock feeding - feeds - resources - food wastes - leftovers - recycling - greenhouse gases - environmental impact - innovations - sustainable animal husbandry - animal production - vee - veevoeding - voer - hulpbronnen - voedselafval - etensresten - broeikasgassen - milieueffect - innovaties - duurzame veehouderij - dierlijke productie

Production of food has re-emerged at the top of the global political agenda, driven by two contemporary challenges: the challenge to produce enough nutritious food to feed a growing and more prosperous human population, and the challenge to produce this food in an environmentally sustainable way. Current levels of production of especially animal-source food (ASF), pose severe pressure on the environment via their emissions to air, water, and soil; and their use of scarce resources, such as land, water, and fossil energy. The livestock sector, for example, is responsible for about 15% of the global anthropogenic emissions of greenhouse gases and uses about 70% of global agricultural land.

Many proposed mitigation strategies to feed the world sustainably, therefore, focus primarily on reducing the environmental impact of the livestock sector, so-called production-side strategies. Other strategies focus on changing consumption patterns by reducing consumption of ASF, or on shifting from ASF with a higher environmental impact (e.g. beef) to ASF with a lower environmental impact (e.g. pork or chicken), so called consumption-side strategies.

Most of the environmental impact of production of ASF is related to production of feed. One production-side strategy to reduce the environmental impact is the use of products that humans cannot or do not want to eat, such as co-products, food-waste, and biomass from marginal lands for livestock feed (referred to as ‘leftover streams’ in this thesis). This strategy is effective, because feeding leftover streams to livestock transforms an inedible food stream into high-quality food products, such as meat, milk, and eggs.

Two production-side strategies that use leftover streams as livestock feed were explored in this thesis: replacing soybean meal (SBM) in diets of growing pigs with either rapeseed meal (RSM) or with waste-fed larvae meal. Replacing SBM with RSM in growing-pig diets was assessed because RSM became increasingly available following an increase in bio-energy production in the EU. In this strategy, therefore, the RSM content in pig diets increased at the expense of SBM. SBM is an ingredient associated with a high environmental impact. It was expected, therefore, that replacing SBM with RSM in pig diets would lead to a decrease in the environmental impact of pork production. Replacing SBM with waste-fed larvae meal was assessed because recent developments show the environmental benefits of rearing insects as livestock feed. Insects have a low feed conversion ratio (kg feed/kg product) and can be consumed completely, without residual materials, such as bones or feathers. The nutritional value of insects is high, especially as a protein source for livestock. Insect-based feed products, therefore, can replace conventional feed ingredients, such as SBM. Altogether this strategy suggests that waste-fed larvae meal might become an important alternative feed source in the future.

To gain insight into the status quo of the environmental impact of both mitigation strategies, replacing SBM with RSM or with waste-fed insects, we first used the attributional life cycle assessment (ALCA) method. Based on the ALCA method, results showed that each mitigation strategy was promising. Replacing SBM with RSM in growing pig diets hardly changed either global warming potential (GWP) or energy use (EU), but decreased land use (LU) up to 16% per kg body weight gain. As expected, feed production had the largest environmental impact, responsible for about 50% of the GWP, 60% of the EU, and 77% of the total LU. Feed production in combination with feed intake, were the most sensitive parameters; a small change in both these two parameters changed the results. Replacing SBM with waste-fed larvae meal in growing-pig diets showed that EU hardly changed, but GWP (29%) and LU (54%) decreased per kg body weight gain. Based on ALCA results, each mitigation strategy, therefore, seems to offer potential to reduce the environmental impact of pork production. An ALCA, however, has two disadvantages: it does not account for product-packages and it does not consider feed-food competition.

The first disadvantage of ALCA was that the complexity of dealing with product-packages is not fully considered. ‘Product-package’ refers to a multiple-output situation. During the processing of sugar beet, for example, beet-pulp and molasses are produced in addition to sugar. Sugar, beet-pulp, and molasses together form a ‘package of products’ because they cannot be produced independently from each other. An ALCA does not account for the fact that the production volume of the co-product(s) depends on the demand for the determining product (e.g. sugar), which results in the limited availability of co-products. Increasing the use of co-products in animal feed, consequently, results in reducing use of a co-product in another sector, requiring them to be replaced with a different product. The environmental impact of increasing the use of a co-product or food-waste, therefore, depends on the net environmental impact. The net environmental impact refers to the environmental benefits of using the product in its new application minus the environmental cost of replacing the product in its old application.

A consequential theoretical framework was developed to account for product-packages. The results, based on the consequential framework, contradicted standard ALCA results. The consequential LCA (CLCA) method we used for replacing SBM with RSM showed an increased GWP (up to 15%), EU (up to 12%), and LU (up to 10%) per kg body weight gain. Moreover, this CLCA method showed that replacing SBM with waste-fed larvae meal increased GWP (60%) and EU (90%), but decreased LU (73%) per kg body weight gain.

Accounting for product-packages increased the net environmental impact of each strategy, replacing SBM with RSM or with waste-fed larvae meal. The difference in results between ALCA and CLCA was especially large in the strategy with waste-fed larvae meal. The difference was caused mainly by the use of food-waste. Food-waste fed to larvae was used initially to produce bio-energy via anaerobic digestion. In CLCA, the environmental impact related to replacing the bio-energy function of food-waste with fossil-energy was included. The net environmental impact became negative, because environmental benefits of replacing SBM with waste-fed larvae meal were less than environmental costs related to the marginal energy source, i.e. fossil energy, replacing the bio-energy. Results of the indirect environmental impact, however, are situation specific: if the marginal energy source were wind or solar energy, the net environmental impact of using waste-fed larvae meal might be positive. Waste-fed larvae meal, therefore, appears to be an interesting mitigation strategy only when energy from wind and solar energy are used more dominantly than energy from fossil sources.

If results were based solely on ALCA, then these potentially negative impacts would have been overlooked. Consideration of the environmental consequences of product-packaging, therefore, is essential to determine total environmental costs. If policy makers or the feed industry want to assess the net environmental impact of a potential mitigation strategy, then we recommend to perform a CLCA instead of an ALCA. The framework developed in this thesis can be used to perform such an assessment.

The second disadvantage of an LCA was that it does not take into account feed-food competition, e.g. competition for land between humans and animals. Most LCA studies focus on the total amount of land required to produce one kg ASF. LCA studies do not account for competition for land between humans and animals, or so-called feed-food competition. In other words, they do not include, differences in the consumption of human-edible products by various livestock species or differences in the suitability of land used for feed production as land to cultivate food-crops directly. Given the global constraints on land, it is more efficient to grow food directly for human consumption rather than for livestock. To address the contribution of livestock to a future sustainable food supply, a measure for land use efficiency was developed, called the land use ratio (LUR). The LUR accounts for plant productivity, efficiency of converting human-inedible feed into ASF, and suitability of land for crop cultivation. The LUR also has a life-cycle perspective.

Results of the LUR illustrated that dairy cows on sandy soil, laying hens, and pig production systems in the Netherlands have a LUR >1.0. In terms of protein produced per m2, therefore, it is more efficient to use these soils for livestock production to produce crops for direct human consumption than to produce feed for livestock. Only dairy cows on peat soil produce human digestible protein (HDP) more efficiently than crops do, because peat is not suitable for crop production. The LUR allows identification of livestock production systems that are able to produce HDP more efficiently than crops do. Livestock systems with a LUR<1.0, such as dairy on peat, have an important role to play in future sustainable nutrition supply.

Results of the LUR showed that livestock production systems using mainly co-products, food-waste, and biomass from marginal land, can produce human digestible protein more efficiently than crop production systems do. The availability of those leftover streams, however, is limited and, therefore, the amount of ASF produced based only on leftover streams is also limited. Because LUR is a ratio, LUR results do not give an indication of how much ASF can be produced based on livestock systems that feed mainly on leftover streams.

The third, and last, mitigation strategy, therefore, focused on the amount of ASF that can be consumed by humans, when livestock are fed only on leftover steams, also referred to as “default livestock”. The calculation of the amount of ASF was based on the assumption that a vegan diet was consumed in principle. The resulting co-products and food-waste were fed to pigs and, biomass from grazing land was fed to ruminants. Results showed that in total 21 g animal source protein per person per day could be produced by feeding livestock entirely on leftovers.

Considering feed-food crops and feeding food-waste made an important contribution to the 21 g of protein that could be produced from default livestock. Considering feed-food crops implies that choices have to be made between different crops, based on their contribution to feed and food production. Oil production from soy cultivation, for example, resulted in the co-product SBM. Results showed that considering feed-food crops can affect the final protein production from pork. The practice of feeding food-waste to livestock is currently prohibited due to problems of food safety but the practice shows potential in extensively reducing the environmental impact of livestock production. Considering feed-food crops and feeding food-waste are examples of mitigation strategies that currently can be implemented to reduce further the environmental impact of the livestock sector.

On average, it is recommended to consume about 57 g of protein from ASF or plant-origin per person per day. Only ASF from default livestock does not fulfil the current global protein consumption of 32 g per person per day, but about one third of the protein each person needs can be produced without any competition for land between feed and food production. To feed the world more sustainably, by requiring livestock production systems with a LUR <1.0, however, a paradigm shift is needed. Global average consumption of ASF should decrease to about 21 g of protein per person per day. Innovations are needed, moreover, to overcome problems of food safety and technical concerns related to collecting the leftover streams. This applies, in particular to food-waste, which is currently unused in livestock production but which presents a valuable strategy in mitigating environmental impacts caused by livestock production. Livestock systems should change their focus, furthermore, from increasing productivity per animal towards increasing protein production for humans per ha. By using leftover streams optimally, the livestock sector is able to produce a crucial amount of protein, while still avoiding competition for land between feed and food crops. Livestock, therefore, can make an important contribution to the future nutrition supply.

Micro-algen in veevoeders : perspectief voor de toekomst?
Dam, Lisanne van - \ 2016
animal nutrition - animal feeding - feeds - feed additives - algae - algae culture - economic viability
Purifying manure effluents with duckweed
Timmerman, M. ; Hoving, I.E. - \ 2016
Wageningen UR Livestock Research (Livestock Research rapport 942) - 27 p.
animal manures - effluents - lemna - aquatic weeds - feeds - nutrients - ingredients - animal feeding - animal nutrition - waste water - biogas - biomass production - cultivation - biobased economy - dierlijke meststoffen - afvoerwater - schadelijke waterplanten - voer - voedingsstoffen - ingrediënten - diervoedering - diervoeding - afvalwater - biomassa productie - teelt
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
Response of broilers on incremental dietary P content and consequences for P- requirements
Krimpen, M.M. van; Dekker, R.A. ; Emous, R.A. van; Bikker, P. ; Bruininx, E.M.A.M. ; Lee, A.G. - \ 2016
Wageningen UR Livestock Research (Livestock Research report 931) - 44 p.
broilers - phosphorus - nutrient requirements - poultry feeding - broiler performance - feeds - poultry farming - vleeskuikens - fosfor - voedingsstoffenbehoeften - pluimveevoeding - vleeskuikenresultaten - voer - pluimveehouderij
The aim of the current experiment was to determine the aP requirements in modern broilers by performing a dose-response experiment. This study showed that for realizing maximal performance, in phase 1 (d1-d10) 5.4 g aP per kg of feed was required, in phase 2 (d11-d21) 4.3 g aP per kg of feed, and in phase 4 (d31-d38) 2.6 g aP per kg of feed. In phase 3 (d22-d30), performance of the broilers was not affected by dietary aP content. For realizing maximal tibia ash content in phase 3, an aP-level of 3.8 g/kg was required.
Efficiënter gebruik van voedermiddelen en (geïmporteerde) diervoedergrondstoffen : mogelijkheden als grondstoffenbron voor de Biobased Economy
Kasper, G.J. ; Duinkerken, G. van; Krimpen, M.M. van; Wagenberg, C.P.A. van; Kals, J. ; Sanders, J.P.M. ; Visser, C.L.M. de - \ 2015
Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 946) - 63 p.
voedertechnologie - voedermiddelbewerking - voer - biomassa - biomassa cascadering - bioraffinage - biobased economy - nederland - haalbaarheidsstudies - gevalsanalyse - feed technology - feed processing - feeds - biomass - biomass cascading - biorefinery - netherlands - feasibility studies - case studies
In this study it was estimated that 6.4 out of 35.0 million tons (dry matter) of animal feeds and raw feed materials that are annually available in the Netherlands, can be used as a resource for application in the biobased economy. Biorefinery enables us to extract feed components that cannot be utilized by animals. The challenge is to add value by applying these components in various value chains (cascading).
Clearing the air: methane and milk
Dijkstra, Jan - \ 2015
dairy cattle - dairy cattle nutrition - feeds - emission - emission reduction - methane - milk protein yield - milk protein - roughage - feed conversion - feed conversion efficiency - climatic change - teaching materials
A field trial on the effects of algae addition to calf feed. Project T2014
Elissen, H.J.H. ; Berg, W. van den; Kootstra, A.M.J. - \ 2015
Lelystad : Wageningen UR, PPO/Acrres (Rapport / PPO-AGV 662) - 41 p.
calves - calf feeding - feed formulation - feeds - veal calves - liveweight - animal health - feed conversion - algae - kalveren - kalvervoeding - voersamenstelling - voer - vleeskalveren - levend gewicht - diergezondheid - voederconversie - algen
This report describes a field trial that took place between 1 July and 2 October 2015 at a Dutch rose veal farm in which a group of 30 calves was fed with formula milk of which 2% of the dry matter was substituted with concentrated freshwater algae. The control group consisted of 25 calves. The farm owners collected the data, which were statistically analyzed and reported at ACRRES. During the trial the following parameters were monitored: calf weight, amounts of formula milk, water, solid feeds, feed additions and medication, deviations in manure structure, and disease incidence. Individual calf weights were determined at arrival and four weighing dates. The main conclusion of this field trial is that the addition of algae to the formula milk of rose veal calves during a period of 44 to 51 days did not have a statistically significant effect on calf weight increase up to 13 weeks after the start of the trial.
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