1,721,032 research outputs found
Modelling of protein metabolism yields amino acid requirements dependent on dietary amino acid efficiency, growth response, genotype and age of growing chicken
No full textFour separate nitrogen balance experiments with fast and slow growing genotypes of growing chicken were conducted to yield basic data for modelling of lysine and threonine requirements dependent on genotype, age, protein deposition and dietary amino acid efficiency. A total of 1008 individual nitrogen balance data in up to four age periods (I: 10-25 days; II: 30-45 days; III: 50-65 days; IV: 70-85 days) was utilised. According to principles of the diet dilution technique, experimental diets provided graded protein supply (60-360 g.kg(-1) crude protein) with lysine or threonine as the first limiting amino acid. The modelling procedure utilised currently observed model parameters for the theoretical potential of nitrogen retention (NR(max)T) and nitrogen maintenance requirement (NMR), respectively. The selected results of the applied modelling procedure are discussed in comparison with current recommendations for growing chickens and aspects of different procedures utilised for assessing quantitative amino acid requirements, respectively. The amino acid requirement data yielded by modelling were in line with current recommendations, but are not directly comparable due to discrepancies in the applied procedures. However, the concluded requirements for lysine and threonine are useful to improve actual predictions for "ideal amino acid ratio' in growing chickens which are in focus of on-going studies
Current knowledge of protein and amino acid nutrition and metabolism in fish
No full textP>Data analysis utilized four growth experiments with mixed diets limiting in lysine, in threonine, and in methionine respectively. All male juvenile Orechromis niloticus [12 g average body weight instead of average (BW) at start, four repetition tanks per diet, 56 days experimental period] provided the database for application of an exponential N-utilization model. Imposing amino acid efficiency data were utilized for modelling of amino acid requirements depending on the level of daily protein deposition. According to the observed average dietary amino acid efficiency of the amino acids under study, 16.3 g/kg of lysine, 8.3 g/kg of threonine and 7.3 g/kg of methionine were established as required in feed content for 187 mg daily protein deposition (50 g BW, feed intake at 3% of BW). Further modelling by use of graded dietary amino acid efficiency yielded strong evidence for the significance of this dietary factor of influence. Current data analysis has led to conclusion, that the applied non-linear modelling of amino acid requirements is an advantageous approach because of its quantitative reflection of graded dietary amino acid efficiency corresponding to protein deposition data. The procedure has the potential to contribute to alternate approaches for improved reliability of recommended quantitative amino acid supply in fish nutrition
Modelling the optimal lysine to threonine ratio in growing chickens depending on age and efficiency of dietary amino acid utilisation
No full text1. Experiments were conducted to establish the requirements and optimal dietary ratio of lysine to threonine for fast growing male chickens (genotype Ross 308) depending on age, daily protein deposition and of dietary amino acid efficiency. 2. A total of 216 growing chickens were utilised in nitrogen-balance studies in three age periods (10 to 25 d; 30 to 45 d; 50 to 65 d) using graded levels of protein supply (60 to 360 g/kg crude protein) in lysine or threonine limiting diets. 3. Supplementation of crystalline amino acids (L-Lys, L-Thr, DL-Met and L-Arg) provided the following amino acid ratios: lysine limiting diets (Lys:Met+Cys:Thr:Arg= 1 : 1.01: 0.91 : 1.14), threonine limiting diets (Lys:Met+Cys:Thr:Arg=1:0.85:0.54:1.16). 4. The principles of the diet dilution technique using an exponential function were applied for the modelling of lysine and threonine requirements. For equal daily protein deposition, optimal lysine to threonine ratios 1 : 0.69 (10 to 25 d), 1: 0.70 (30 to 45 d) and 1: 0-74 (50 to 65 d) were established. 5. For the commercial growth period of fast growing chickens, the derived optimal lysine to threonine ratio was constant (1:069). The applied modelling procedure gave conclusions for quantitative requirements and optimal dietary lysine:threonine ratios in line with actual recommendations
Different sources of microbial phytase in plant based low phosphorus diets for Nile tilapia Oreochromis niloticus may provide different effects on phytate degradation
No full textConclusive experimental data regarding different sources of supplemented microbial phytase in tilapia feed are very scarce. An experiment was conducted using plant based diets (24.5% soybean meal; 11.5% wheat gluten; 22.5% com; 32.5% wheat) containing graded supply (500, 750, 1000, 1250 U/kg) of microbial phytase from two different sources (experimental phytase SP 002; Ronozyme((R))P). Additionally, a negative control diet (0.41% total P; 0.15% non-phytate P; no phytase added) and a positive control diet (0.88% total P; 0.62% non-phytate P; no phytase added) were examined. Apparent nutrient digestibility (0.3% titanium dioxide as marker) was measured using six sedimentation systems (0.15 m(3) /system) with external sedimentation column. Triplicate groups of 10 fish (average BW 110 g) fed 3 times a day and feces collection was conducted within 4 h following each feeding period. Chyme of the proximal small intestine (hepatic loop) was sampled for measuring phytate P. In a subsequent study, blood sampling was conducted from the caudal peduncle vein (triplicates from 9 fish per diet; average BW 125 g) for monitoring of inorganic P concentration in plasma at 2, 4, 8 and 12 h following the last meal. Phytase supplementation significantly improved digestibility of protein, calcium and phosphorus. Disappearance of phytate P from the hepatic loop was significantly improved due to pbytase SP 1002 and the course of inorganic plasma P concentration indicated superior release of phytate P from the plant based diet under study. (C) 2007 Elsevier B.V. All rights reserved
Lysine efficiency in piglets fed diets with a phytogenic feed additive and conclusion of lysine requirement data
No full textTwo experiments were conducted to examine effects of a commercial phytogenic feed additive (PEA), containing inulin, an essential oil mix (carvacrol, thymol), and chest nut meal (polyphenols) on nutrient digestibility, protein utilization, and lysine efficiency in piglets. Each experiment utilized sixteen piglets (male castrated, 8 wk) and four experimental groups. Experiment I studied graded levels of the PEA (0, 0.05, 0.1, 0.15%) in lysine limited diets (wheat, barley, soyabcan meal, fish meal). Experiment 2 examined 0.1% of the PFA and two dietary levels of lysine. The results indicated that apparent nutrient digestibility, protein utilization, and lysine efficiency were not significantly affected by the PEA (P>0.05). Observed daily lysine requirements (7.3, 9.9 and 13.1 g for 76, 100, 124 g daily protein deposition) in growing barrows (20-30 kg body weight) were in line with recommendations and contribute to the limited database for modelling of lysine requirements in piglets
Optimal dietary lysine to threonine ratio in pigs (30-110 kg BW) derived from observed dietary amino acid efficiency
No full textOptimal ratio of lysine (Lys) to threonine (Thr) in diets for growing barrows [genotype: Pietrain X (Large White X German Landrace)] was established at 30, 50, 70, 90 and 110 kg body weight (BW). N balance studies were conducted with diets based on constant mixture of wheat, barley, soybean meal and field peas. Supplementation of crystalline amino acids (AA) provided diets with Lys (diet A) and Thr (diet B) in first limiting position. For each BW range, totally 28 individual N balance data were utilized for assessing model parameters (exponential N utilization model) of dietary efficiency of Lys and Thr, respectively. Observed maximal dietary efficiency of Lys and Thr provided the database for conclusion of optimal dietary Lys to Thr ratio. Based on applied experimental conditions, BW dependent Lys to Thr ratio could not be concluded. On average, the dietary ratio Lys to Thr = 1:0.61 +/- 0.02 was obtained as optimal for growing pigs.Lohmann Animal Health GmbH & Co. KG, Cuxhaven, German
Nutrient utilization of Nile tilapia Oreochromis niloticus fed plant based low phosphorus diets supplemented with graded levels of different sources of microbial phytase
No full textExperimental results regarding nutrient and phosphorus (P) utilization due to different sources of microbial phytase in tilapia nutrition are very scarce. An experiment was conducted with plant based diets (24.5% soybean meal; 11.5% wheat gluten; 22.5% corn; 32.5% wheat) containing moderate native phytase activity (<300 FTU/kg). For comparison, a negative control diet (0.41% total P; 0.15% non-phytate P; no phytase added) and a positive control diet (0.88% total P; 0.62% non-phytate P; no phytase added) were used. Experimental diets with graded levels (500, 750, 1000, 1250 FTU/kg) of two different sources of microbial phytase (experimental phytase SP 1002; Ronozyme(R) P) were assigned in four repetition tanks and fed to juvenile all male Nile tilapia (average body weight 13.50 g) for 60 days. The efficiency of phytase supplementation was evaluated based on parameters of growth response, body composition, nutrient deposition and nutrient utilization following submission to ANOVA (P<0.01) and Tukey-test. Significant: improvements due to phytase addition (P<0.01) were found for growth, feed conversion ratio, protein efficiency ratio, specific growth rate and nutrient deposition. Phytase supplementation increased energy-, protein- and phosphorus utilization significantly. In addition, the mineral composition of scale and vertebra was significantly affected. Ash content of scale and vertebra as well as P content in the ash of scale and vertebra were significantly increased due to improved P availability in the diet. Based on ingredients and composition of the diet under study, the experimental phytase SP1002 expressed superior performance data compared to Ronozyme P. Supplementation of 750 FTU/kg from phytase SP 1002 was similar to an inorganic P supplementation. (C) 2005 Elsevier B.V. All rights reserved
Lysine requirement studies in modern genotype barrows dependent on age, protein deposition and dietary lysine efficiency
No full textN balance experiments were conducted to derive age-dependent model parameters for modelling of lysine (Lys) requirements in growing pigs. Modern genotype barrows from 16 litters were utilized (four piglets/litter) at 15, 30, 50, 70, 90 and 110 kg body weight respectively. Six diets provided graded dietary protein supply (40 to 320 g/kg) by a constant mixture of barley, wheat, potato protein, wheat gluten, soybean protein concentrate and crystalline amino acids. Lys was set as the first limiting dietary amino acid. Each age period provided 24 N balance data (n = 4) to derive N maintenance requirement (NMR) and theoretical maximum for daily N retention (NR(max)T) by non-linear regression analysis. At high dietary Lys efficiency, 17-18 g daily Lys intake was required for 170 g daily protein deposition. To achieve similar daily protein deposition, pigs need 21-23 g Lys if the Lys efficiency is 20% lower. For higher daily protein deposition (195-200 g) and varying dietary Lys efficiency, between 22 and 29 g Lys was required. The Lys requirement data yielded by modelling were in line with current recommendations. Further developments of the approach are discussed to improve age-independent applications
Modeling of Threonine Requirement in Fast-Growing Chickens, Depending on Age, Sex, Protein Deposition, and Dietary Threonine Efficiency
No full textIn addition to dose-response studies, modeling of N utilization, depending on intake of the first limiting amino acid in the diet, is one of the tools for assessing amino acid requirements in growing animals. Based on a verified nonlinear N-utilization model and following the principles of the diet dilution technique, N-balance experiments were conducted to estimate the Thr requirement of fast-growing chickens (genotype Cobb), depending on age, sex, CP deposition. and efficiency of dietary Thr utilization. Different predictions were made for the feed intake to conclude the optimal Thr concentration in the feed. The results are based on N-balance experiments with a total of 144 male and 144 female growing chickens within 4 age periods (1: 10 to 25 d; 11: 30 to 45 d; 111: 50 to 65 d; TV: 70 to 85 d), using diets with graded protein supply (6.6, 13, 19.6, 25.1, 31.8, and 37.6% CP in DM) from high-protein soybean meal with a constant amino acid ratio and Thr as the first limiting amino acid (3.87 g of Thr/100 g of CP; dietary Lys:Thr=1:0.54). The observed optimal Thr concentration (% of feed) was influenced by age, sex, level of CP deposition, dietary efficiency of Thr utilization, and predicted feed intake. For male chickens, assuming an average CP deposition (60% of the potential) and average efficiency of Thr utilization, 0.78% (10 to 25 d), 0.73% (30 to 45 d), 0.65% (50 to 65 d), and 0.55% (70 to 85 d) total dietary Thr were observed as optimal total Thr concentration in the diet (corresponding to 60, 135, 160, and 180 g of daily feed intake, respectively). Data are discussed in context with the main factors of influence like age, sex, level of daily CP deposition, efficiency of dietary Thr utilization, and predicted feed intake
Modelling of threonine and methionine requirements of Oreochromis niloticus due to principles of the diet dilution technique
No full textTwo growth studies (56 days) were conducted with juvenile all male Oreochromis niloticus, using six mixed diets with threonine and five mixed diets, with methionine as the first limiting amino acid (LAA), respectively. Diets were randomly assigned to four repetition tanks with 25 fish per tank. Growth results and body nutrient analyses yielded protein deposition data depending on the uptake of the LAA. For further modelling, a nonlinear N-utilization model was utilized for assessing the dietary efficiency of threonine and methionine utilization, respectively. By use of the observed dietary AA efficiency, threonine and methionine requirement data were established, depending on the daily protein deposition. The optimal dietary AA concentrations (8.3 g kg(-1) versus 9.9 g kg(-1) threonine; 7.3 g kg(-1) versus 8.8 g kg(-1) methionine) were derived for 70% of the potential for protein deposition (NDmaxT) and predicted daily feed intake (3% versus 2.5% of BW). Observed methionine requirements are imposing for the upper limit for methionine replacement by cystine and minimal catabolism of methionine to yield cystine. Generally, the modelling provided requirement data in line with current recommendations. Variation of the dietary AA efficiency by modelling procedure ranks this factor as very important for the conclusion of amino acid requirement data
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