围产期饲粮中添加异位酸对奶牛生产性能、营养物质表观消化率、瘤胃发酵参数和奶牛、新生犊牛血清指标的影响

Effects of Adding Isoacids in Perinatal Diets on Performance, ApparentDigestibility of Nutrients, Rumen Fermentation Parameters of DairyCows, and Serum Indicators of Dairy Cows and Newborn Calves

本试验旨在研究围产期饲粮中添加异位酸对奶牛生产性能、营养物质表观消化率、瘤胃发酵参数和奶牛、新生犊牛血清指标的影响,为异位酸添加剂在奶牛生产中的合理添加使用提供理论依据。选取18头健康、第3胎次、预产期相近的经产荷斯坦围产期奶牛,按照完全随机区组设计分为3组,每组6个重复,每个重复1头奶牛。对照组饲喂基础饲粮,Ⅰ组饲喂基础饲粮+30 mL/(d·头)的异位酸,Ⅱ组饲喂基础饲粮+60 mL/(d·头)的异位酸。预试期10 d,正试期42 d,从奶牛产前21 d开始到产后21 d结束。结果表明:1)在产后10和21 d,Ⅰ、Ⅱ组产奶量均显著高于对照组(P<0.05)。2)Ⅰ、Ⅱ组干物质(DM)、粗蛋白质(CP)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)表观消化率均显著高于对照组(P<0.05)。Ⅰ、Ⅱ组瘤胃氨态氮(NH 3-N)含量均显著低于对照组(P<0.05);Ⅱ组瘤胃微生物蛋白(MCP)、乙酸和总挥发性脂肪酸含量均显著高于对照组(P<0.05)。3)在产前10 d,Ⅱ组奶牛血清球蛋白(GLB)含量显著高于对照组(P<0.05)。在分娩当天,奶牛血清白蛋白(ALB)含量显著高于对照组和Ⅰ组(P<0.05)。在产前10 d和产后21 d,Ⅱ组奶牛血清尿素氮(UN)含量均显著低于对照组(P<0.05)。在产后21 d,Ⅰ、Ⅱ组奶牛血清葡萄糖(GLU)含量显著高于对照组(P<0.05)。4)在产前10 d,Ⅰ组奶牛血清谷胱甘肽过氧化物酶(GSH-Px)活性显著高于对照组(P<0.05),在产后10和21 d,Ⅱ组均显著高于对照组(P<0.05)。在分娩当天和产后10 d,Ⅱ组奶牛血清丙二醛(MDA)含量均显著低于对照组(P<0.05)。在分娩当天,Ⅰ组奶牛血清总抗氧化能力(T-AOC)显著高于对照组(P<0.05),在产后10 d,Ⅱ组显著高于对照组(P<0.05)。5)在产前10 d和分娩当天,Ⅱ组奶牛血清免疫球蛋白G(IgG)含量均显著高于对照组(P<0.05)。在分娩当天,Ⅱ组奶牛血清免疫球蛋白M(IgM)含量显著高于对照组和Ⅰ组(P<0.05)。6)Ⅰ、Ⅱ组新生犊牛血清GSH-Px活性均显著高于对照组(P<0.05),Ⅰ组新生犊牛血清IgA、IgG含量显著高于对照组(P<0.05)。综上所述,在围产期饲粮中添加异位酸可提高奶牛产奶量、营养物质表观消化率、瘤胃发酵参数、奶牛的抗氧化及免疫能力,并在一定程度上增强新生犊牛的抗氧化和免疫能力。本试验中,奶牛围产期饲粮中异位酸适宜添加量为60 mL/(d·头)。

The aim of this experiment was to investigate the effects of adding isoacids to the diet during the perinatal period on performance,apparent digestibility of nutrients,rumen fermentation parameters of dairy cows,and serum indicators of dairy cows and newborn calves,and to provide theoretical basis for the rational addition and use of allotopic acid additives in dairy production.A total of 18 healthy Holstein dairy cows with similar 3 parities and expected perinatal dates were divided into 3 groups according to a completely random block design with 6 replicates per group and 1 cow per replicate.The control group cows were only fed a basic diet,while the groupⅠcows were fed the basic diet+30 mL/d isoacids per cow,while the groupⅡcows were fed the basic diet+60 mL/d isoacids per cow.The pre-feeding period lasted for 10 days and the trial period lasted for 42 days,from 21 days before to 21 days after delivery.The results showed as follows:1)on day 10 and 21 after delivery,the milk yield in groupⅠand groupⅡI was significantly higher than that in the control group(P<0.05).2)The apparent digestibility of dry matter(DM),crude protein(CP),neutral detergent fiber(NDF)and acid detergent fiber(ADF)in groupsⅠandⅡwas significantly higher than that in the control group(P<0.05).The ammoniacal nitrogen(NH 3-N)content in groupsⅠandⅡwas significantly lower than that in the control group(P<0.05);the microprotein(MCP),acetic acid,and total volatile fatty acids contents in groupⅡwere significantly higher than those in the control group(P<0.05).3)On day 10 before delivery,serum globulin(GLB)content in groupⅡwas significantly higher than that in the control group(P<0.05).On day of delivery,the serum white protein(ALB)content was significantly greater than that in control group and groupⅠ(P<0.05).On day 10 before delivery and day 21 after delivery,the urine nitrogen(UN)content in groupⅡwas substantially lower than that in controlled group(P<0.05).On day 21 after delivery,serum glucose(GLU)content in groupsⅠandⅡwas significantly higher than that in control group(P<0.05)4)On day 10 before delivery,serum glucose peroxide(GSH-Px)activity in groupⅠwas significantly higher than that in the control group(P<0.05),and groupⅡwas markedly higher on days 10 and 21 after delivery compared with the control group(P<0.05).Serum malondialdehyde(MDA)content in groupⅡwas significantly lower than that in the control group(P<0.05)both on the day of delivery and day 10 after delivery.Serum total antioxidant capacity(T-AOC)on the day of delivery in groupⅠwas considerably higher than that in control group(P<0.05),and group II was notably higher than control group on day 10 after delivery(P<0.05).5)Serum immunoglobulin G(IgG)content in groupⅡwas significantly higher than that in the control group(P<0.05)both on day 10 before and the day of delivery.Serum immunoglobulin M(IgM)content in groupⅡwas significantly higher on the day of delivery than that in the control group and groupⅠ(P<0.05).6)Serum GSH-Px content of newborn calves in groupsⅠandⅡwas significantly higher than that in control group(P<0.05),serum IgA and IgG contents of newborn calves in groupⅠwere significantly higher than those in control group(P<0.05).In conclusion,adding isoacids to the diet can improve the milk production,apparent digestibility of nutrients,rumen fermentation parameters,and antioxidant and immune abilities of cows during the perinatal period,and to some extent enhance the antioxidant and immune abilities of newborn calves.In this experiment,the optimal supplemental level of isoacids in perinatal diet is 60 mL/d per cow.