低氮日粮条件下生长猪标准回肠可消化异亮氨酸需要量研究

Study on Requirement of Standardized Ileal Digestible Isoleucine for Growing Pigs Fed Low Crude Protein Diets

本试验旨在研究低氮日粮条件下20~75 kg生长猪(20~50、50~75 kg 2个阶段)标准回肠可消化异亮氨酸(SID Ile)与标准回肠可消化赖氨酸(SID Lys)的适宜比例。试验一选取108头体重为(21.48±0.50)kg的杜×长×大生长猪,随机分为3个处理组,即对照组(高氮日粮组)、低氮日粮高SID Lys组和低氮日粮低SID Lys组,每个处理6个重复,每个重复6头猪,研究SID Lys的限制性水平。试验二以试验一的限制性SID Lys水平设计日粮,选取180头体重为(21.46±0.48)kg的杜×长×大生长猪,随机分为5个处理组,每个处理6个重复,每个重复6头猪。2个体重阶段日粮SID Ile:SID Lys设为5个不同水平,以研究其适宜比例。结果表明:试验一中低氮日粮低SID Lys组猪的耗料增重比(F:G)显著高于对照组和低氮日粮高SID Lys组(P<0.05);在试验二中,当日粮SID Ile∶SID Lys分别为0.48和0.56时,20~50、50~75 kg生长猪获得最大的日增重(ADG)和最佳的F:G。综上所述,20~50、50~75 kg生长猪日粮粗蛋白(CP)水平分别为14%和12.4%时,其适宜的日粮SID Ile:SID Lys别为0.48和0.56。

This study was designed to investigate the optimal standardized ileal digestible（SID） isoleucine（Ile） to lysine（Lys） ratios for 20-75 kg growing pigs（divided into two stages of 20-50 and 50-75 kg） fed low protein diets. Two experiments were conducted. Exp. 1, a total of 108 Duroc×Landrace×Large White pigs with body weight of（21.48±0.50） kg were selected and randomly divided into three treatments, containing a control diet（high protein diet） and two low protein diets with high or low SID Lys, with 6 pens per treatment and 6 pigs per pen to study the restrictive levels of SID Lys. The diets of Exp. 2 were designed according to the restrictive levels of SID Lys of Exp. 1. A total of 180 Duroc×Landrace×Large White pigs with body weight of（21.46±0.48） kg were selected and randomly divided into five treatments with 6 pens per treatment and 6 pigs per pen..Five levels of SID Ile to Lys ratios were designed in both stages to study the optimum ratios. The results showed that, in Exp. 1, compared with the control diet and the low protein diet with high SID Lys, the low protein diet with low SID Lys significantly increased the feed：gain ratio（F：G）（P〈0.05）. In Exp. 2, the maximum ADG and optimum F：G of 20-50 and 50-75 kg growing pigs were obtained when the SID Ile to Lys ratios were 0.48 and 0.56, respectively. It is concluded that, the optimum SID Ile to Lys ratios for 20-50 and 50-75 kg growing pigs were 0.48 and 0.56, respectively, when the diet CP levels were 14% and 12.4%, respectively.