夏季补饲半胱胺和烟酸铬对水牛泌乳性能、抗氧化性能、瘤胃发酵参数和微生物多样性的影响

Effects of Supplemental Feeding of Cysteamine and Chromium Nicotinate on Lactation Performance,Antioxidant Performance,Rumen Fermentation Parameters and Microbial Diversity of Buffalo in Summer

本试验旨在研究夏季补饲半胱胺和烟酸铬对水牛泌乳性能、抗氧化性能、瘤胃发酵参数和微生物多样性的影响。选取体重[(615±21)kg]、胎次(3~5胎)和产奶量(5~6 kg/d)相近的健康泌乳中期尼里-拉菲奶水牛20头,采用单因素随机区组设计分为4组(Ⅰ、Ⅱ、Ⅲ和Ⅳ组),每组5头。Ⅰ组为对照组,饲喂基础饲粮;Ⅱ组、Ⅲ组、Ⅳ组为试验组,其中Ⅱ组饲喂基础饲粮+22.5 g/(d·头)半胱胺,Ⅲ组饲喂基础饲粮+24 mg/(d·头)铬(烟酸铬形式,下同),Ⅳ组饲喂基础饲粮+22.5 g/(d·头)半胱胺+24 mg/(d·头)铬。试验在2019年7—8月开展,预试期1周,正试期4周。结果显示:1)补饲烟酸铬和半胱胺对水牛体表温度和呼吸频率均无显著影响(P>0.05);与Ⅰ组比较,Ⅳ组的直肠温度显著降低(P<0.05)。2)Ⅰ组的干物质采食量显著低于Ⅱ组和Ⅳ组(P<0.05);Ⅳ组的粗蛋白质和中性洗涤纤维表观消化率显著高于Ⅰ组(P<0.05)。3)Ⅳ组的产奶量显著高于其他组(P<0.05);Ⅲ组和Ⅳ组的4%乳脂校正乳产量显著高于Ⅰ组和Ⅱ组(P<0.05);Ⅲ组的乳蛋白率显著高于Ⅰ组和Ⅳ组(P<0.05);Ⅲ组的乳总固形物含量显著高于其他组(P<0.05)。4)Ⅱ组和Ⅲ组瘤胃液乙酸含量显著高于Ⅰ组(P<0.05);Ⅱ组、Ⅲ组和Ⅳ组瘤胃液丙酸、异丁酸、总挥发性脂肪酸和微生物蛋白含量显著高于Ⅰ组(P<0.05);各组瘤胃液丁酸、氨态氮、异戊酸含量以及pH、乙酸/丙酸差异不显著(P>0.05)。5)Ⅳ组乳中C12∶0、C14∶0、C16∶0、C18∶2(顺-9,反-11)、C20∶3n3含量显著低于Ⅰ组(P<0.05);Ⅲ组和Ⅳ组乳中C16∶0含量显著低于Ⅰ组(P<0.05)。6)各组间血清过氧化氢酶、总超氧化物歧化酶和谷胱甘肽过氧化物酶活性差异不显著(P>0.05);Ⅱ组和Ⅳ组血清丙二醛含量显著低于Ⅰ组(P<0.05),总抗氧化能力显著低于Ⅳ组(P<0.05)。Ⅱ组和Ⅳ组血清生长激素含量显著高于Ⅰ组(P<0.05);Ⅲ组血清雌二醇含量显著高于Ⅰ组和Ⅱ组(P<0.05)。Ⅳ组血清甲状腺素含量显著高于Ⅰ组(P<0.05);Ⅲ组血清谷草转氨酶活性较Ⅰ组显著提高(P<0.05)。7)补饲烟酸铬和半胱胺均能显著提高水牛瘤胃液细菌数量(P<0.05);Ⅱ组水牛瘤胃液产甲烷菌数量较Ⅰ组显著提高(P<0.05)。Ⅱ和Ⅲ组瘤胃液拟杆菌门的相对丰度较Ⅰ组有所提高,而厚壁菌门的相对丰度较Ⅰ组降低。综上可知,夏季同时补饲半胱胺和烟酸铬提高了水牛的干物质采食量,改善了养分表观消化率、泌乳性能、瘤胃发酵参数和微生物组成,进而缓解了夏季热应激对水牛机体造成的不良影响。

The purpose of this experiment was to study the effects of supplemental feeding of cysteamine and chromium nicotinate lactation performance,antioxidant performance,rumen fermentation parameters and microbial diversity of buffalo in summer.A single-factor randomized block design was used in this experiment.Twenty healthy Nile-Rafi milk buffaloes with similar body weight[(615±21)kg],parity(3 to 5 parities)and milk yield(5 to 6 kg/d)were selected and divided into 4 groups(groupsⅠ,Ⅱ,ⅢandⅣ)with 5 buffaloes in each group.GroupⅠwas the control group,and buffaloes in the groupⅠwere fed a basal diet.GroupsⅡ,ⅢandⅣwere test groups,and buffaloes in the groupsⅡ,ⅢandⅣwere fed the basal diet+22.5 g/(d·head)cysteamine,the basal diet+24 mg/(d·head)chromium(chromium nicotinate form,the same below)and the basic diet+22.5 g/(d·head)cysteamine+24 mg/(d·head)chromium,respectively.The experiment was carried from June to August of 2019.The pre-feeding period was 1 week and the test period was 4 weeks.The results showed as follows:1)supplemental feeding of chromium nicotinate and cysteamine had no significant effects on the surface temperature and respiratory rate of buffalo(P>0.05).Compared with groupⅠ,the rectal temperature of groupⅣdecreased significantly(P<0.05).2)The dry matter intake of groupⅠwas significantly lower than that of groupsⅡandⅣ(P<0.05).The apparent digestibility of crude protein and neutral detergent fiber of groupⅣwas significantly higher than that of groupⅠ(P<0.05).3)The milk yield of groupⅣwas significantly higher than that of groupsⅠ,ⅡandⅢ(P<0.05).The yield of 4%fat corrected milk(FCM)of groupsⅢandⅣwas significantly higher than that of groupsⅠandⅡ(P<0.05).The milk protein rate of groupⅢwas significantly higher than that of groupsⅠandⅣ(P<0.05).The milk total solid content of groupⅢwas significantly higher than that of other groups(P<0.05).4)The content of acetate in rumen fluid of groupsⅡandⅢwas significantly higher than that of groupⅠ(P<0.05).The contents of propionate,isobutyrate,total volatile fatty acids and microbial protein in rumen fluid of groupsⅡ,ⅢandⅣwas significantly higher than that of groupⅠ(P<0.05).The differences of butyrate content,acetate/propionate,ammonia nitrogen content,pH and isovalerate content in each group were not significant(P>0.05).5)The contents of C12∶0,C14∶0,C16∶0,C18∶2(cis-9,trans-11),and C20∶3n3 in the milk of groupⅣwere significantly lower than those of groupⅠ(P<0.05);the content of C16∶0 in the milk of groupsⅢandⅣwas significantly lower than that of groupⅠ(P<0.05).6)There were no significant differences in serum catalase,total superoxide dismutase and glutathione peroxidase activities among groups(P>0.05);the content of serum malondialdehyde of groupsⅡandⅣwas significantly lower than that of groupⅠ(P<0.05),and the serum total antioxidant capacity was significantly lower than that of groupⅣ(P<0.05).The content of serum growth hormone of groupsⅡandⅣwas significantly higher than that of groupⅠ(P<0.05);the content of serum estradiol of groupⅢwas significantly higher than that of groupsⅠandⅡ(P<0.05).The content of serum thyroxine of groupⅣwas significantly higher than that of groupⅠ(P<0.05);the activity of serum aspartate aminotransferase of groupⅢwas significantly higher than that of groupⅠ(P<0.05).7)Supplemental feeding of chromium nicotinate and cysteamine could significantly increase the number of bacteria in rumen fluid(P<0.05);the number of methanogen in rumen fluid of groupⅡwas significantly higher than that of groupⅠ(P<0.05).The relative abundance of Bacteroidetes in rumen fluid of groupsⅡandⅢwas higher than that in groupⅠ,while the relative abundance of Firmicutes was lower than that in groupⅠ.In summary,the simultaneous feeding of cysteamine and chromium nicotinate in summer can increase the dry matter intake of buffaloes,and improve the apparent digestibility of nutrients,lactation performance,rumen fermentation parameters and microbial composition,and thus alleviate the adverse effects of heat stress on the body of buffaloes.