尿素硫酸铵与蛋氨酸对山羊氨基酸消化代谢的影响

THE EFFECTS OF UREA-AMMONIA SULFATE AND METHIONINE ON AMINO ACID DIGESTION AND METABOLISM IN GOATS

利用3头装有瘤胃瘘管和十二指肠 T 形瘘管的阉公山羊研究了复胃、肠道中氨基酸的消化代谢和血浆游离氨基酸的水平.试验分3期:Ⅰ.基础日粮加10g 尿素;Ⅱ.以Ⅰ期为基础,并经十二指肠瘘管灌注蛋氨酸(Met)3g/天;Ⅲ.基础日粮添加7g 尿素和硫酸铵5.6g.3期日粮氮含量相同,约为2.40%.结果如下:Ⅰ、Ⅱ、Ⅲ期进入十二指肠的总氨基酸(TAA)分别为38.52g/天,45.10g/天和50.30g/天(P<0.05);日粮氨基酸(AA)组成经复胃消化代谢后有较大变化,以胱氨酸(Cys)的消化率最高,达78.19%;十二指肠起始端食糜和粪便中氨基酸的组成较为稳定,似乎不受日粮组成影响;Ⅰ、Ⅱ、Ⅲ期肠道中的 TAA表观消化率,分别为64.14%,70.02%和70.93%,而且各种 AA 不同,以 Cys 最低;血液支链氨基酸(BCAA)水平因十二指肠灌注 Met 而下降(p<0.05);尿素浓度则Ⅲ期较低.

Three goats fitted with rumen fistula and T-shaped cannula were used in the experi-ments,which included 3 seriers:basal diet contained urea served as Ⅰ,further extra infu-sion Met 3.0 g into duodenum as Ⅱ and addition of urea 7.0g and ammonia sulfate 5.6g in-stead of urea 10.0g as Ⅲ.N accounted for about 2.4% in each trial.The results showed thatflow of total amino acid to the duodenum was 38.52g/d,45.10g/d,50.30g/d for trialⅠ,Ⅱ,Ⅲ,respectively(P<0.05).Cys was considerably disappeared from stomach(about 78.19%).The Amino acid composition of the digesta and feces was constant in thethree trials condition.Apparent digestibility(AD)of amino acid in the intestine was64.14% in Ⅰ,70.02% in Ⅱ and 70.93% in Ⅲ.The AD of individual amino acid with thehighest(76.55%)for Met and the lowest(48.56%)for Cys.After infusion of Met intoduodenum,the concentration of BCAA in plasma was significantly lower(P<0.05)than inⅠor in Ⅲ.The concentration of Urea-N in plasma was lowest in Ⅲ.