Comparative Study On The Effects Of Four Antibiotics Supplementation In Corn Stalk-based Diet On Digestion And Metabolism In Sheep

The effects of 4 antibiotics supplementation in corn stalk-based diet were studied on digestion andmetabolism in sheep (experiment 1) and in rumen (experiment 2). In experiment 1: Thirty Male XinjiangMerino sheep, 19kg live weight, divided randomly into 5 groups (n=6 each group), were fed with cornstalk-based diet plus 150g concentrate supplied with flavomycin (30.0mg/kg), hainanmycin (13.3mg/kg),maduramicin (6.7mg/kg) and oxytetracycline (120mg/kg) respectively (the control group supplied withnon-antibiotics). The concentrate was fed equivalently per day, and the corn stalk prayed with 10g urea perkg was fed ad libitum. In experiment 2: Five ruminally and duodenaly cannulated Xinjiang Merino sheep,28kg body weight, assigned in a 5×5 Latin square design. The usage of the 4 antibiotics and the dietfeeding method were the same as in experiment 1. The results showed that supplementation of 4 antibioticscould improve the intake of corn-stalk to some extent. The digestibility of cellulose and hemi-cellulosewere improved to some degree. The digestibility of them in oxytetracycline group was improved 6.8%(P<0.05),7.0%(P<0.05)respectively with the best effect. The addition of 4 antibiotics had no significanteffect on nitrogen digestion, while the retention of nitrogen were improved by 54.2%(P<0.01),29.9%(P<0.05),12.5% and 43.1%(P<0.05)in flavomycin, hainanmycin, maduramicin and oxytetracycline. Itshowed that antibiotics had positive effect on nitrogen metabolism. The pH value and the concentration ofNH3-N in rumen were not affected by supplementation of antibiotics significantly. The crude proteinflowed to duodenal was increased respectively by 3.9%,15.8%(P<0.05),16.3%(P<0.05),19.3(P<0.05)in flavomycin, hainanmycin, maduramicin and oxytetracycline group, in which the proportion of ruminalundegradated protein was improved by 8.2%,14.4%,13.2%,15.6%, respectively. It indicated that theutilization of nitrogen of microbe in rumen was modified by the supplement of antibiotics. Thedisappearance of OM was decreased by 7.5%,10.9%(P<0.05),11.8(P<0.05)in hainanmycin,maduramicin and oxytetracycline group, respectively, while the apparent digestibility of OM in sheep wereimproved to some extent.