摘要
选择 6头体重 5 0 0～ 6 0 0kg ,安装有瘤胃、十二指肠前端和回肠末端瘘管的阉牛 ,分 3期依次饲喂以玉米、棉粕和氨化稻草为原料配合的 3种不同饲养水平的日粮。每种饲养水平下 ,依次从十二指肠灌注 4种不同的氨基酸混合液 ,测定相应的氮平衡值、血清尿素和血清游离氨基酸浓度。其中 ,饲喂高水平日粮时 ,4种灌注处理分别为 :Lys+Met+Thr、Met+Thr、Lys+Thr和Lys+Met;饲喂中等水平和低水平日粮时 ,4种灌注处理分别为 :Lys+Met+Val、Met+Val、Lys+Val和Lys+Met。结果显示 ,3种饲养水平下 ,不同灌注处理对氮平衡值有显著影响 (P <0 0 5 )。在高水平日粮条件下 ,与Lys +Met+Thr处理相比 ,回撤Lys、Met和Thr时 ,氮平衡值分别减少了 10 2 3、8 83和 7 2 8g/d(P <0 0 5 ) ;在中等水平的日粮条件下 ,与Lys+Met+Val处理相比 ,回撤Lys、Met和Val时 ,氮平衡值分别减少了 5 4 1、3 4 1和 1 6 0 g/d(P <0 0 5 ) ;在低水平日粮条件下 ,与Lys +Met+Val处理相比 ,回撤Lys、Met和Val时 ,氮平衡值分别减少了 8 4 5、5 14和 2 78g/d(P <0 0 5 ) ,各种回撤处理间的氮平衡也差异显著 (P <0 0 5 )。 3种饲养水平下 ,血清尿素。
Six 500-600 kg steers with ruminal,duodenal and ileac cannula were fed high level(HL),middle level(ML)and low level(LL)diets in turn based on corn,cottonseed meal and ammoniated rice straw during three 39-day periods.At each feeding level,four different mixtures of amino acids were infused through duodenal cannula.Nitrogen balance(NB),serum urea(SU)and individual free amino acids(SAA)were measured.At HL,the four infusion treatments were Lys+Met+Thr,Met+Thr,Lys+Thr and Lys+Met.At ML and LL,the four infusion treatments were Lys+Met+Val,Met+Val,Lys+Val and Lys+Met. The results indicated that different infusion treatments have significant effects on NB(P<0.05).At HL,NB decreased 10.24,8.83,7.29 g/d respectively (P<0.05) when Lys,Met and Thr were removed in turn in comparison with Lys+Met+Thr infusion.At ML,NB decreased 5.41,3.41,1.60 g/d respectively (P<0.05) when Lys,Met and Val were removed in turn in comparison with Lys+Met+Val infusion.At LL,NB decreased 8.45, 5.14, 2.78 g/d(P<0.05) respectively when Met,Val and Lys were removed in turn in comparison with Lys+Met+Val infusion.There were also significant differences (P<0.05) of NB between other three infusions at each feeding level.SU,total SAA or individual SAA except for amino acids removed varied oppositely to NB,but there were no significant differences(P>0.05) between most of infusions.Based on responses of NB to different infusions,Lys,Met and Thr was the first,second and third limiting amino acid respectively when HL diet was fed;Lys,Met and Val was the first,second and third limiting amino acid respectively when ML diet was fed and Met,Val and Lys was the first,second and third limiting amino acid respectively when LL diet was fed. Based on metabolic body weight,NB had regressive relations as follows with Lys and Met apparently absorbable in the small intestine respectively: NB=-0.2829+2.5106×Lys apparently absorbable in the small intestine R=0.9984 n=3 NB=-0.2974+7.7493×Met apparently absorbable in the small intestine R=0.9850 n=3 Based on these regressive equations,requirements of Lys and Met apparently absorbable in the small intestine for maintenance in growing beef cattle were 0.1127 and 0.0384 g/kgW 0.75/d,respectively.If scurf N loss was considered,requirements of Lys and Met apparently absorbable in the small intestine for maintenance in growing beef cattle were 0.1206 and 0.0410 g/kgW 0.75/d,respectively.The ratio of lys requirement to Met requirement is 100/34,while the ratio of Lys concentration to Met concentration in the whole empty body protein is 100/31.
出处
《畜牧兽医学报》
CAS
CSCD
北大核心
2003年第2期112-119,共8页
ACTA VETERINARIA ET ZOOTECHNICA SINICA
基金
"九五"国家重点科技攻关计划项目 ( 96-0 0 3)
关键词
生长肉牛
赖氨酸
蛋氨酸
氮代谢
Growing beef cattle
Lysine
Methionine
Nitrogen metabolism
