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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    Effects of feed ingredients on nutrient digestibility, nitrogen/energy balance and morphology changes in the intestine of Nile tilapia (Oreochromis niloticus)
    Tran-Ngoc, Kim T. ; Haidar, Mahmoud N. ; Roem, Arjen J. ; Sendão, João ; Verreth, Johan A.J. ; Schrama, Johan W. - \ 2019
    Aquaculture Research 50 (2019)9. - ISSN 1355-557X - p. 2577 - 2590.
    digestibility - feed ingredient - intestinal morphology - nitrogen and energy balance

    The present study assessed the effect of different feed ingredients on nutrient apparent digestibility coefficients (ADC), nitrogen/energy balance and morphology changes in the intestine of Nile tilapia; using a control diet and six test diets, in which the following six ingredients were included at 30%: hydrolysed feather meal (HFM), soybean meal (SBM), rice bran (RB), rapeseed meal (RM), sunflower meal (SFM) and dried distillers grains with solubles (DDGS). The proximal, middle and distal intestine was processed for quantitative histology counting the number of goblet cells (GC), and measuring the thickness of lamina propria (LP) and submucosa (SM). The study showed that the ADC of protein in raw materials were highest in SBM (92.2%), followed by SFM (90.2%), DDGS (89.2%), RM (87.8%), HFM (86.9%) and RB (84.0%). The nutrient ADCs had no correlation with intestinal morphology changes. Only the SBM diet caused noticeable changes in intestinal morphology such as an increase the thickness of SM and LP and the number of GC. The diet composition, however, altered the protein efficiency and the maintenance energy requirement. Protein retention efficiency was the lowest in fish fed HFM and the highest in RB. The highest maintenance energy requirements were observed in HFM and SBM treatments.

    Energy efficiency of digestible protein, fat and carbohydrate utilisation for growth in rainbow trout and Nile tilapia
    Schrama, Johan W. ; Haidar, Mahmoud N. ; Geurden, Inge ; Heinsbroek, Leon T.N. ; Kaushik, Sachi J. - \ 2018
    The British journal of nutrition 119 (2018)7. - ISSN 0007-1145 - p. 782 - 791.
    Bioenergetics - Digestible nutrients - Energy efficiency - Energy evaluation - Energy metabolism - Fish nutrition - Net energy

    Currently, energy evaluation of fish feeds is performed on a digestible energy basis. In contrast to net energy (NE) evaluation systems, digestible energy evaluation systems do not differentiate between the different types of digested nutrients regarding their potential for growth. The aim was to develop an NE evaluation for fish by estimating the energy efficiency of digestible nutrients (protein, fat and carbohydrates) and to assess whether these efficiencies differed between Nile tilapia and rainbow trout. Two data sets were constructed. The tilapia and rainbow data set contained, respectively, eight and nine experiments in which the digestibility of protein, fat and energy and the complete energy balances for twenty-three and forty-five diets was measured. The digestible protein (dCP), digestible fat (dFat) and digestible carbohydrate intakes (dCarb) were calculated. By multiple regression analysis, retained energy (RE) was related to dCP, dFat and dCarb. In tilapia, all digestible nutrients were linearly related to RE (P<0·001). In trout, RE was quadratically related to dCarb (P<0·01) and linearly to dCP and dFat (P<0·001). The NE formula was NE=11·5×dCP+35·8×dFAT+11·3×dCarb for tilapia and NE=13·5×dCP+33·0×dFAT+34·0×dCarb-3·64×(dCarb)2 for trout (NE in kJ/(kg0·8×d); dCP, dFat and dCarb in g/(kg0·8×d)). In tilapia, the energetic efficiency of dCP, dFat and dCarb was 49, 91 and 66 %, respectively, showing large similarity with pigs. Tilapia and trout had similar energy efficiencies of dCP (49 v. 57 %) and dFat (91 v. 84 %), but differed regarding dCarb.

    Effect of constant digestible protein intake and varying digestible energy levels on energy and protein utilization in Nile tilapia
    Haidar, M.N. ; Bleeker, S. ; Heinsbroek, L.T.N. ; Schrama, J.W. - \ 2018
    Aquaculture 489 (2018). - ISSN 0044-8486 - p. 28 - 35.
    Digestible energy - Digestible protein - Energy utilization - Feed evaluation - Protein efficiency - Protein/Energy ratio
    In literature, the variability in the estimated optimal digestible protein to digestible energy ratio (DP/DE) is high. The present study aimed to estimate the optimal DP/DE ratio in Nile tilapia (Oreochromis niloticus) using different criteria (performance, energy and nitrogen balances parameters). Duplicate aquaria were randomly assigned to one of 16 diets. These diets covered a wide range of dietary DP/DE ratio (from 16.7 to 27 g MJ −1 ). DP levels ranged between 36 and 50% and DE levels between 17.5 and 22 MJ kg −1 . Fish were fed restrictively based on a similar digestible protein amount at all 16 diets. Initial fish weight was 6.7 g. Broken line analysis showed that no optimal DP/DE ratio was present for Nile tilapia within the DP/DE ratio range studied. Regression analysis showed that growth declined as DP/DE ratio increased and seemed to level off at high DP/DE ratio (25 g MJ −1 ). FCR ranged between 0.8 and 1.1 and increased linearly with increasing DP/DE ratio. Decreasing the DP/DE ratio resulted in a linear increase in protein efficiency to a highest value of 53%. However, protein efficiency did not show a plateau or a maximum value. Moreover, decreasing the DP/DE ratio resulted in a very high fat content of the fish (over 16%). In conclusion, an optimal DP/DE ratio in Nile tilapia being fed restrictively seems to be absent or to be below 16 g MJ −1 . A maximum protein deposition level is not present in 5–40 g Nile tilapia.
    Nijltilapia verteert verenmeel slecht
    Haidar, M. - \ 2017
    The evaluation of energy in fish feed
    Haidar, Mahmoud - \ 2017
    Wageningen University. Promotor(en): J.A.J. Verreth, co-promotor(en): J.W. Schrama. - Wageningen : Wageningen University - ISBN 9789463438049 - 155
    oreochromis niloticus - fish feeding - feed formulation - digestible energy - dietary protein - dietary fat - carbohydrates - growth - feed evaluation - fish culture - aquaculture - oreochromis niloticus - visvoeding - voersamenstelling - verteerbare energie - voedingseiwit - voedingsvet - koolhydraten - groei - voederwaardering - visteelt - aquacultuur

    New and alternative plant ingredients are increasingly incorporated in fish feed due to the scarcity of captured fish and increased fishmeal and fish oil prices. As a result, current fish feeds are characterized by a highly variable ingredients composition, leading to a similar variability in the dietary macronutrients composition, especially the carbohydrates fraction. Appropriate formulation of the energy component in fish feeds requires information on nutrient digestibility, energy requirements for maintenance, and the efficiency of utilization of digestible energy for growth (kgDE). In fish feed formulation, the energy evaluation is based on digestible energy (DE) basis. The main assumptions of this DE system are that maintenance requirements and kgDE are independent of dietary factors. The main objective of this thesis was to evaluate and improve the DE system for Nile tilapia. Data showed that, opposite to what is assumed in literature and irrespective of the feeding level applied, an optimal digestible protein to digestible energy ratio (DP/DE) for young Nile tilapia could not be detected. In addition, it was expected that Nile tilapia would show a maximal protein deposition in relation to a wide range of DP/DE ratios, however, this was either observed. Further investigations showed that different body compartments/organs responded differently in terms of protein and fat composition as a result of changes in the dietary DP/DE ratio. In tilapia, viscera and the “rest” fraction (head, skin, fins and bones) were the main site for fat retention. In addition, protein content of fillets seems to be constant (about 17%) and not affected by dietary factors in Nile tilapia. In addition, the effect of using new plant ingredients in Nile tilapia diets was also investigated. The results showed that the ingredients composition had an effect on the maintenance requirements of Nile tilapia. Further, changes in the ratio of starch vs non starch carbohydrates revealed that energy retention was lower when more dietary fibers were included. In addition, the net energy retention differed also when the levels of digestible protein, fat and carbohydrates changed in the diets. The latter results proved that kgDE was not constant and was dependent on diet composition. All aforementioned results led us to calculate the energetic efficiencies of digestible protein, fat and carbohydrates for net energy retention. These estimated efficiencies were used to propose a net energy evaluation system being feasible for Nile tilapia.

    Effect of varying dietary non protein energy level and source on energy utilization efficiency in common carp (cyprinus carpio)
    Haidar, M. ; Groot, Ruben ; Hoftijzer, Maarten ; Figueiredo-Silva, A.C. ; Masagounder, K. ; Schrama, J.W. - \ 2016
    - 2 p.
    The effect of type of carbohydrate (starch vs. nonstarch polysaccharides) on nutrients digestibility, energy retention and maintenance requirements in Nile tilapia
    Haidar, Mahmoud N. ; Petie, Mischa ; Heinsbroek, Leon T.N. ; Verreth, Johan A.J. ; Schrama, Johan W. - \ 2016
    Aquaculture 463 (2016). - ISSN 0044-8486 - p. 241 - 247.
    Energy utilization - Non-starch polysaccharides - Maintenance requirements - Fish
    For Nile tilapia, the energetic value of non-starch polysaccharides (NSP) was compared to starch. It was assessed if carbohydrate type (NSP vs. starch) affected the energetic utilization for growth (KgDE) and the energy requirements for maintenance (DEm). Eighteen groups of fish were assigned in 2 × 3 factorial design: two diets, with either a high NSP or high starch content; and three feeding levels (low, medium or satiation). The NSP diet contained 70% of the starch diet supplemented with 30% dried distillers grains with solubles. Nutrients digestibility, nitrogen and energy balances were measured. All nutrients digestibility decreased with increasing feeding level (P < 0.001). Diet type (NSP vs. starch) affected the digestibility of all nutrients except for dry matter and fat. NSP of both diets were digested and the NSP digestibility ranged between 23% and 73%. Averaged over feeding levels, 5% and 17% of the total digestible energy originated from NSP at the starch and NSP diet, respectively. Although the digestible energy intake was similar, the contrast in type of carbohydrates between the diets resulted in lower energy retention with the NSP rich diet (P < 0.05). Despite this impact on energy retention, both DEm and kgDE were not significantly influence by diet. However, DEm was numerically higher (96 vs. 110 kJ kg-0.8 BW d-1) and kgDE was numerically lower (65% vs. 58%) at the NSP diet compared to the starch diet. In conclusion, NSP are digested by Nile tilapia. Digested NSP are less well utilized for growth, which is reflected by a lower energy retention in fish and is due to the slightly higher DEm in combination with a slightly lower kgDE. Statement of relevance: Scarcity of fishmeal and -oil combined with the fast growing aquaculture sector, result in diversification of feed ingredients in fish-feeds. Plant ingredients as protein source become more important, which also increases the dietary carbohydrate content including non-starch polysaccharides (NSP). This paper provides information on the nutritional value of NSP in tilapia. This will eventually lead to improved fish-feed formulations.
    Is there an optimal dietary DP/DE ratio for Nile Tilapia? (oral presentation)
    Haidar, Mahmoud - \ 2015
    Nile Tilapia and dietary DP/DE ratio: Is there an optimal ratio? (poster)
    Haidar, M. ; Bleeker, S. ; Heinsbroek, L.T.N. ; Schrama, J.W. ; Verreth, J.A.J. - \ 2015
    The energetic value of non-starch polysaccharides in Nile tilapia (Oreochromis niloticus)
    Haidar, M. ; Petie, M. ; Heinsbroek, L.T.N. ; Schrama, J.W. ; Verreth, J.A.J. - \ 2014
    The utilization of digestible energy for growth in relation to dietary macronutrients composition in Nile tilapia (Oreochromis niloticus)
    Haidar, M. ; Schrama, J.W. ; Verreth, J.A.J. - \ 2014
    Control of voluntary feed intake in fish: a role for dietary oxygen demand in Nile tilapia (Oreochromis niloticus) fed diets with different macronutrient profiles
    Subramanian, S. ; Geurden, I. ; Figueiredo-Silva, A.C. ; Kaushik, S.J. ; Haidar, M.N. ; Verreth, J.A.J. ; Schrama, J.W. - \ 2012
    The British journal of nutrition 108 (2012)8. - ISSN 0007-1145 - p. 1519 - 1529.
    trout oncorhynchus-mykiss - bass dicentrarchus-labrax - salmon salmo-salar - rainbow-trout - energy-utilization - food-intake - body-composition - dynamic action - gadus-morhua - lipid-levels
    It has been hypothesised that, at non-limiting water oxygen conditions, voluntary feed intake (FI) in fish is limited by the maximal physiological capacity of oxygen use (i.e. an ‘oxystatic control of FI in fish’). This implies that fish will adjust FI when fed diets differing in oxygen demand, resulting in identical oxygen consumption. Therefore, FI, digestible energy (DE) intake, energy balance and oxygen consumption were monitored at non-limiting water oxygen conditions in Nile tilapia fed diets with contrasting macronutrient composition. Diets were formulated in a 2 × 2 factorial design in order to create contrasts in oxygen demand: two ratios of digestible protein (DP):DE (‘high’ v. ‘low’); and a contrast in the type of non-protein energy source (‘starch’ v. ‘fat’). Triplicate groups of tilapia were fed each diet twice daily to satiation for 48 d. FI (g DM/kg0·8 per d) was significantly lower (9·5 %) in tilapia fed the starch diets relative to the fat diets. The DP:DE ratio affected DE intakes (P <0·05), being 11 % lower with ‘high’ than with ‘low’ DP:DE ratio diets, which was in line with the 11·9 % higher oxygen demand of these diets. Indeed, DE intakes of fish showed an inverse linear relationship with dietary oxygen demand (DOD; R 2 0·81, P <0·001). As hypothesised (‘oxystatic’ theory), oxygen consumption of fish was identical among three out of the four diets. Altogether, these results demonstrate the involvement of metabolic oxygen use and DOD in the control of FI in tilapia.
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