87,285 research outputs found
Threonine Requirement of Slow-Growing Male Chickens Depends on Age and Dietary Efficiency of Threonine Utilization
No full textNitrogen-balance experiments were conducted with a total of 288 male chickens to assess Thr requirement data on 2 commercial slow-growing genotypes (I 657 and Red JA from Hubbard ISA) by use of a modeling procedure described previously. Six graded levels of dietary protein supply from high-protein soy-beanmeal were used within 4 age periods (period I: 10 to 25 d; period II: 30 to 45 d; period III: 5 to 65 d; and period IV: 70 to 85 d). The provided dietary amino acid ratio (Lys: Met + Cys: Thr = 1:0.85:0.54), with 3.87% Thr in the feed protein, identified Thr as the first limiting dietary amino acid. The nitrogen maintenance requirement (NMR) was established by exponential approximation of N excretion depending on N intake (on average, NMR = 173 mg of N/BWkg0.67 per d). The theoretical maximum for daily N deposition was estimated by the Levenberg-Marquardt algorithm (SPSS program, version 11.5) and by exponential fitting of N balance data depending on N intake. The observed dietary Thr efficiency was used to model Thr requirements for a given protein deposition depending on age. The optimal dietary Thr concentration (percentage of feed) was established by different predictions for daily feed intake. Daily CP deposition of approximately 60% of the potential required 0.83 and 0.87% (10 to 25 d), 0.73 and 0.75% (30 to 45 d), 0.66 and 0.69% (50 to 65 d), and 0.51 and 0.53% (70 to 85 d) of Thr in feed for genotype I 657 and genotype Red JA, respectively (average daily feed intakes of 30, 75, 100, and 100 g in age periods I to IV). Results of model calculations need verification in comparative growth studies with assessment of nutrient deposition and varying dietary Thr efficiencies
Lysine requirement of fast growing chickens –effects of age, sex, level of protein deposition and dietary lysine efficiency
No full textLysine requirement of fast growing chickens –effects of age, sex, level of protein deposition and dietary lysine efficiency
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Nitrogen maintenance requirement and potential for nitrogen deposition of intensive growing chicken depending on age and sex
No full textZur Modellierung von Lysin- und Threoninbedarfswerten von Broilern unterschiedlicher genetischer Herkunft
No full textThreonine requirement of extensive broiler genotypes depending on performance and efficiency of threonine utilisation
No full textFirst conclusion about threonine requirement of male growing chicken of extensive genotype depending on age and protein deposition
No full textMisleading conclusion about lysine requirement of growing chicken by dose-response studies when feed intake is a factor of influence
No full textMisleading conclusion about lysine requirement of growing chicken by dose-response studies when feed intake is a factor of influence
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