饲养方式和饲粮能量水平对牦牛生长性能、瘤胃发酵参数和瘤胃菌群的影响

Effects of Feeding Model and Dietary Energy Level on Growth Performance,Rumen Fermentation Parameters and Rumen Bacterial Community of Yaks

本试验旨在探究饲养方式和饲粮能量水平对牦牛生长性能、瘤胃发酵参数和瘤胃菌群的影响。采用3×2双因素试验设计,在散栏和栓系2种饲养方式下饲喂低、中、高3种能量水平[综合净能(NE_(mf))分别为5.51、6.22、6.94 MJ/kg]的全混合日粮(TMR)。选取体重(269.75±35.46)kg、健康无病的公牦牛60头,随机分为6组,分别为栓系低能组(TL组)、栓系中能组(TM组)、栓系高能组(TH组)、散栏低能组(CL组)、散栏中能组(CM组)、散栏高能组(CH)组,每组10头牛。预试期15 d,正试期90 d。结果显示:1)栓系饲养方式下,牦牛的终末体重和平均日增重随饲粮能量水平的增加而升高,TH组显著高于TL和TM组(P<0.05);散栏饲养方式下,牦牛的终末体重和平均日增重随饲粮能量水平的增加呈现先升高后降低的趋势,CM组显著高于CL组(P<0.05)。散栏饲养方式下,CM组的料重比最小,显著低于CL和CH组(P<0.05)。2)瘤胃液氨态氮(NH_(3)-N)浓度以CM组最低,显著低于CL、CH、TL和TH组(P<0.05)。在2种饲养方式下,瘤胃液乙酸浓度随饲粮能量水平的增加而显著降低(P<0.05)。在栓系饲养方式下,瘤胃液丙酸浓度随饲粮能量水平的增加而升高,但组间差异不显著(P>0.05);在散栏饲养方式下,瘤胃液丙酸浓度随饲粮能量水平的增加先升高而后降低,CM组显著高于CH和CL组(P<0.05)。3)在栓系饲养方式下,拟杆菌门和普雷沃氏菌属的相对丰度随着饲粮能量水平的升高显著增加(P<0.05);在散栏饲养方式下,CM组拟杆菌门的相对丰度最高,显著高于CH组(P<0.05)。综上可知,饲养方式和饲粮能量水平对牦牛生长性能、瘤胃发酵参数和瘤胃菌群产生了影响。总体上来看,散栏饲养方式优于栓系饲养方式,中能量水平饲粮提高了牦牛的生长性能,改善了瘤胃发酵参数和瘤胃菌群组成,因此,散栏饲养方式下饲粮NE_(mf)为6.22 MJ/kg时是较适宜进行牦牛冷季育肥的条件。

This experiment was conducted to investigate the effects of feeding method and dietary energy level on the growth performance,rumen fermentation parameters and rumen bacterial community of yaks.A 3×2 two-factor experimental design was adopted in this experiment,under the two feeding models of tether and casual bar,yaks were fed total mixed rations(TMR)with low,medium and high energy levels[combined net energy(NE_(mf))were 5.51,6.22 and 6.94 MJ/kg,respectively].A total of sixty adult healthy male yaks with body weight of(269.75±35.46)kg were allotted in three groups,they were tether+low energy level(TL group),tether+medium energy level(TM group),tether+high energy level(TH group),casual bar+low energy level(CL group),casual bar+medium energy level(CM group)and casual bar+high energy level(CH group),and each group had 10 yaks.The pre-test period was 15 days,and the trial period was 90 days.The results showed as follows:1)the final body weight and average daily gain(ADG)of yaks under the tether feeding model increased with the increase of dietary energy level,and those of the TH group were significantly higher than those of the TL and TM groups(P<0.05).The final body weight and ADG of yaks under the casual bar feeding model both increased firstly and then decreased,and those of the CM group were significantly higher than those of the CL group(P<0.05).Under the casual bar feeding model,the feed/gain(F/G)of the CM group was the smallest,which was significantly lower than that of the CL and CH groups(P<0.05).2)The ammonia nitrogen(NH_(3)-N)concentration in rumen fluid of the CM group was the lowest,which was significantly lower than that of the CL,CH,TL and TH groups(P<0.05).The concentration of acetic acid in rumen fluid was significantly decreased with the increase of dietary energy level under the two feeding models(P<0.05).Under the tether feeding model,the concentration of propionic acid in rumen fluid was increased with the increase of dietary energy level,but the difference was not significant(P<0.05);under the casual bar feeding model,the concentration of propionic acid in rumen fluid was increased firstly and then decreased with the increase of dietary energy level,and that of the CM group was significantly higher than that of the CH and CL groups(P<0.05).3)Under the tether feeding model,the relative abundances of Bacteroidetes and Prevotella were significantly increased with the increase of dietary energy level(P<0.05);under the casual bar feeding model,the Bacteroidetes of the CM group had the highest relative abundance,which was significantly higher than that of the CH group(P<0.05).In conclusion,feeding model and dietary energy level have an impact on the growth performance,rumen fermentation parameters and rumen bacterial community of yaks.In general,the casual bar feeding model is better than the feeding model.The diet with medium energy level can improve the growth performance of yaks,improve the rumen fermentation parameters and rumen bacterial community composition.So,the diet with 6.22 MJ/kg NE_(mf)under casual bar feeding model is suitable for yak fattening in cold season.