Body Protein Deposition And True Ileally Digestible Lysine Utilization In Growing Pigs Housed In 23℃ To 35℃ Environments

A study was conducted to determine the effect of hot temperature on body protein deposition and lysine utilization in pigs from 20 to 100kg live weight. 80 pigs(DxLxY) were assigned to one of twenty experimental treatments in a 4.5 factorial arrangement with effects including live weight (20-40kg ,40-60kg, 60-80kg, 80-100kg) and environment temperature(23 ℃,26℃,29℃,32℃,35℃).The ideal protein diets were formulated by corn and soybean meal to meet the fifth-limiting amino acid ;Animals were given ad libitum access to food until 20kg was gained. Protein deposition and Lys retention were calculated based on comparative slaughter and ileal distal contents was collected for determining the true ileally digestibility of amino acids as pigs were killed .The study indicated that the true ileally digestibility of Lysine was not affected by environment temperature, and protein deposition and the retention efficiency of true ileally digestible lysine(retention/intake) decreased with environment temperature and live weight increasing. Heavier live weight, hotter temperature ,bigger effect was shown. Live weight(20- 100kg) had no significant effect on N retention when environment temperature reached 32℃.lg protein deposited needed 0.13g true ileally digestible Lysine above maintenance requirement (36 mg/kgBW0.75) in 23℃ Regression formulations were: Y-21.156+4.867BW-0.021BW2-0.079TxBWR2=0.767 SE=13.10 p<0.01 Y -Protein deposition ( g/d); T-- temperature(℃); BW-- live weight(kg)Y=2.472-0.063T-0.02B W+0.513XR2=0.915 SL-0.543 p<0.01Y -Lys retention (g/d); T--temperature(℃); BW- live weight(kg); X- Lys intake (g/d)...