Maintenance valine, isoleucine, and tryptophan requirements for poultry

摘要: Poultry maintenance requirements for valine, isoleucine, and tryptophan were measured by nitrogen balance using different unit systems. The trial lasted 5 d with 48 h of fasting (with roosters receiving only water+sucrose) the last 72 feeding excreta collection. Forty grams each diet first-limiting in or was fed tube day (3 d) to give a range intakes from 0 101, 119, 34 mg/kg BW tryptophan, respectively. A nitrogen-free containing energy, vitamins, minerals, meeting rooster requirements, offered ad libitum during these three d. To confirm that amino acids studied limiting, treatment added control formulated adding 0.24 g/kg L-valine, 0.21 L-isoleucine, 0.10 L-tryptophan diets lower acid level. Excreta collected 3 period content analyzed. For acid, linear regression between retention (NR) intake performed. equations were: NR=-98.6 (±10.1)+2.4 (±0.2)×Val, NR=-46.9 (±7.1)+2.3 (±0.1)×Ile, NR=-39.5 (±7.7)+7.3 (±0.4)×Trp; where Val, Ile, Trp are body weight per d, required maintain at zero NR calculated be 41, 20, system mg kg metabolic weight, 59, 32, 9, Considering degree maturity animal protein (BPm (0.73)×u), amounts 247, 134, 37 (0.73)×u) Maintenance requirement is more adequately expressed as content.