长白×北京黑杂交猪氮沉积规律的研究

NITROGEN RETENTION OF LANDRACE × BEIJING BLACK F_1 CROSSBRED PIGS

应用氮平衡方法测定了长白×北京黑杂交一代阉公猪的氮沉积能力与氮代谢规律。20～90千克体重阶段内的日粮氮消化率变动于82.3％与84.8％之间,无随体重增大而呈一定变化的趋势。日粮蛋白质的生物学价值因试验猪体重增大而直线下降(y=66.44-0.374x),导致尿氮排出(占吸收氮的％)增加和氮沉积能力(g/kg^(0.75))及日粮净蛋白质利用率的下降,后二者与体重的关系分别为y=1.8027-0.0139x和y=58.06-0.36x。测定结果还表明,试验猪的氮沉积峰值在体重60千克左右出现,其最大日氮沉积量约为20克。

A nitrogen balance experiment was conducted with Landrace × Beijing Black F1 crossbred pigs to measure its pattern of nitrogen metabolism. It was found that in the body weight range of 20 to 90 kg the digestibility of dietary nitrogen varied between 82.3% and 84.8%. No correlation was observed between nitrogen digestibility and body weight. As body weight increased the biological values of dietary protein decreased linearly. This caused an increase in the output of urine nitrogen and decrease in both the potential of nitrogen retention of pigs and the utilization efficiency of dietary nitrogen. Experimental results also indicated that for Landrace x Beijing Black barrows nitrogen retained per day reached its peak at about 60 kg body weight with a daily retention of 20 g.