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    Estimation of the standardized ileal digestible valine to lysine ratio required for 25- to 120-kilogram pigs fed low crude protein diets supplemented with crystalline amino acids
    时间: 2015     来源: 农业部饲料中心

    作者:Liu XT, Ma WF, Zeng XF, Xie CY, Thacker PA, Htoo JK and Qiao SY*
    期刊:J Anim Sci.2015.93 doi: 10.2527/jas2015-9308
    摘要:Four 28-d experiments were conducted to determine the standardized ileal digestible (SID) valine (Val) to lysine (Lys) ratio required for 26- to 46- (Exp. 1), 49- to 70- (Exp. 2), 71- to 92- (Exp.3), and 94- to 119-kg (Exp. 4) pigs fed low CP diets
    supplemented with crystalline AA. The first 3 experiments utilized 150 pigs (Duroc × Landrace × Large White), while Exp. 4 utilized 90 finishing pigs. Pigs in all 4 experiments were randomly allocated to 1 of 5 diets with 6 pens per treatment (3 pens of barrows and 3 pens of gilts) and 5 pigs per pen for the first 3 experiments and 3 pigs per pen for Exp. 4. Diets for all experiments were formulated to contain SID Val to Lys ratios of 0.55, 0.60, 0.65, 0.70, or 0.75. In Exp. 1 (26 to 46 kg), ADG increased (linear, P = 0.039; quadratic,P = 0.042) with an increasing dietary Val:Lys ratio.The SID Val:Lys ratio to maximize ADG was 0.62 using a linear broken-line model and 0.71 using a quadratic model. In Exp. 2 (49 to 70 kg), ADG increased (linear, P = 0.021; quadratic, P = 0.042) as the SID Val:Lys ratio increased. G:F improved (linear, P =0.039) and serum urea nitrogen (SUN) decreased (linear,P = 0.021; quadratic, P = 0.024) with an increased SID Val:Lys ratio. The SID Val:Lys ratios to maximize ADG as well as to minimize SUN levels were 0.67 and 0.65, respectively, using a linear broken-line model and 0.72 and 0.71, respectively, using a quadratic model. In Exp. 3 (71 to 92 kg), ADG increased (linear, P = 0.007;quadratic, P = 0.022) and SUN decreased (linear, P =0.011; quadratic, P = 0.034) as the dietary SID Val:Lys ratio increased. The SID Val:Lys ratios to maximize ADG as well as to minimize SUN levels were 0.67 and 0.67, respectively, using a linear broken-line model and 0.72 and 0.74, respectively, using a quadratic model.In Exp. 4 (94 to 119 kg), ADG increased (linear,P = 0.041) and G:F was improved (linear, P = 0.004;quadratic, P = 0.005) as the dietary SID Val:Lys ratio increased. The SID Val:Lys ratio to maximize G:F was 0.68 using a linear broken-line model and 0.72 using a quadratic model. Carcass traits and muscle quality were not influenced by SID Val:Lys ratio. In conclusion,the dietary SID Val:Lys ratios required for 26- to 46-, 49- to 70-, 71- to 92-, and 94- to 119-kg pigs were estimated to be 0.62, 0.66, 0.67, and 0.68, respectively,using a linear broken-line model and 0.71, 0.72, 0.73,and 0.72,respectively, using a quadratic model.