仔猪苏氨酸营养需要量的研究

STUDIES ON THE REQUIREMENTS OFTHREONINE FOR PIGLETS

为研究早期断奶仔猪苏氨酸需要量，用大白仔猪进行了生长———代谢实验（体重７～２０ｋｇ）和大长北仔猪饲养实验（体重６～１０～２０ｋｇ），其结果为：①为获得最大日增重和最好饲料报酬，７～２０ｋｇ体重大白仔猪日粮总苏氨酸（ＴＴＨＲ）和可消化苏氨酸（ＤＴＨＲ）适宜含量分别为０．７５％、０．６１％；大长北仔猪分别为０．７５％、０．６４％（６～１０ｋｇ体重）和０．６２％、０．５３％（１０～２０ｋｇ体重）。此ＴＴＨＲ水平相当于美国ＮＲＣ（１９８８）标准相应阶段推荐量的１１０％。②以玉米、豆粕、花生粕为主要原料的５～２０ｋｇ体重仔猪日粮，适宜的必需氨基酸比例（总氨基酸为基础）估计为：赖／含硫／苏／色＝１００：６５：６５：２０。以此必需氨基酸模式配制仔猪日粮，可取得较好的饲养效果，氮沉积和血清尿素氮（ＳＵＮ）浓度较低。③随着日粮苏氨酸水平由８０％ＮＲＣ（１９８８）推荐量增加到１１０％ＮＲＣ（实验１）和１２０％（实验２），仔猪ＳＵＮ浓度逐渐下降。ＳＵＮ可以作为评价仔猪日粮氨基酸平衡和苏氨酸含量是否适宜的指标之一。④在本实验条件下，日粮不同苏氨酸浓度并未引起仔猪血清胆固醇（实验１）、白蛋白、球蛋白（实验２）含量的明显差别。在实验?

For estimating the requirements of threonine for piglets,two experiments were conducted using Large White(LW) piglets weighing 5～20kg in a growing-metabolism experiment and Large White×Landrace×Beijing Black(LW×LR×BB)piglets weighing 6～10kg and 10～20kg in feeding one.The results showed: 1.To obtain the maximum body weight gain and the best feed conversion efficiency,the adequate contents of threonine in diets for 7～20kg body weight LW piqlets were 0.75% as total threonine(TTHR) and 0.61% as digestible threonine(DTHR),for 6～10kg and 10～20kg body weight LW×LR×BB pigltes were 0.75%、0.62% as TTHR and 0.64%、0.53% as DTHR,respectively. 2.The optimum ratios of lysine:sulfur amino acids(methionine and cystine):threonine:tryptophane in the diets kept consisted of corn,soybean meal and peanut meal were 100:65:65:20 as total amino acids for 5～20kg body weight piglets .The piglets fed those diets kept above amino acid pattern had the better performance,higher nitrogen retention and the lower content of serum urea nitrogen(SUN). 3.The levels of SUN were lowered with increasing dietary contents of THR from 80% NRC(1988) to 110% NRC in Expt.1 and to 120% NRC in Expt.2;there was negative correlation between the concentration of SUN of piglets and the dietary contents of TTHR .These results suggested the concentration of SUN is a sensitive index responding the status of equilibration of amino acids and the adaptabilities of THR levels in diets for piglets. 4.According to our experiments,the differences of concentrations of serum cholesterol(Expt.1),albumin,total protein and globulin(Expt.2)were not significant among the different dietary THR levels for piglets.In Expt.1,the concentration of serum triglycerid from piglets fed the diet containing 100% NRC level(0.75%)was significantly lower(P<0.01)than those fed diets with 80%,90%,110% and 120% NRC levels,and alkalne phosphatase in sera was higher(P<0.05)than others.The concentration of glutamate-pyruvate transminase in sera from piglets fed the diet with 110% NRC was higher(P<0.05) than those with 80%,90%,100% and 120% NRC (1998)levels.