低饲粮阴阳离子差补镁对山羊体液酸碱平衡、 血钙与镁、瘤胃发酵参数的影响

Effects of Low Dietary Cation-Anion Difference with Magnesium Supplementation on Fluid Acid-Based Balance,Blood Calcium and Magnesium,and Rumen Fermentation Parameters of Goats

试验旨在探究低饲粮阴阳离子差(DCAD)补镁对山羊体液酸碱平衡、血钙与镁、瘤胃发酵参数的影响。采用交叉试验设计,将6只年龄、体重相一致的黔北麻羊随机分为2组:对照组、试验组,每组3个重复,每个重复1只羊。对照组饲喂基础饲粮,DCAD为75 mmol/kg(干物质基础)、Mg为0.07%。试验组在基础饲粮的基础上添加MgCl2·6H2O(45 g/d)和MgO(10 g/d),DCAD为-111 mmol/kg(干物质基础)、Mg为0.33%。试验分2个阶段交叉进行,每个阶段15 d,持续30 d。结果表明:①随着饲喂时间的延长,试验组山羊尿液pH显著低于对照组(P<0.05)。②试验组血浆Ca2+、Mg2+、1,25-二羟基维生素D3(1,25-(OH)2VD3)、细胞膜钙泵(PMCA1b)水平显著高于对照组(P<0.05),甲状旁腺素(PTH)、维生素D受体(VDR)、钙结合蛋白(CaBP-D9k)水平差异不显著(P>0.05)。③试验组瘤胃缓冲力与纤维二糖酶活性显著升高(P<0.05),瘤胃pH、氨态氮(NH3-N)、挥发性脂肪酸(VFA)及其他纤维素酶活指标与对照组差异不显著(P>0.05)。低饲粮阴阳离子差补镁可降低体液酸碱平衡,提高瘤胃缓冲力和纤维酶活性,显著提升血钙与镁及其代谢因子浓度。

This experiment was to explore the ef⁃fects of low dietary cation-anion difference(DCAD)with Mg supplementation on fluid acidbased balance,blood calcium and magnesium,and rumen fermentation parameters of goats.Six Qianbei miscellaneous goats with similar age and weight were randomly divided into two groups,which were the control group and the treatment group,with three replications per group and one goat per repli⁃cation in a cross-over study design.The DCAD and Mg were 75 and 0.07%,respectively in the control group.The experimental group added MgCl2·6H2O(45 g/d)and MgO(10 g/d)on the basis of the basic di⁃et,with DCAD of-111 mmd/kg and Mg of 0.33%.The experiment was carried out in two overlapping stages,each of which lasted for 15 days and lasted for 30 days.The results showed that:①The urine pH of goats in the treatment group significantly decreased with time than that of the control(P<0.05).②The concentrations of plasma Ca2+,Mg2+,1,25-(OH)2VD3,PMCAlb in the treatment group were signifi⁃cantly higher than those in the control group(P<0.05),but not for PTH,VDR and CaBP-D9k(P>0.05).③Rumen buffer capacity and cellobiase activity in the treatment group were significantly increased compared with the control group(P<0.05),but there were no significant differences in rumen pH,NH3-N,VFA and other cellulose enzyme activity indexes compared with the control group(P>0.05).Low di⁃etary cation-anion difference with Mg supplementation could reduce fluids acid-base balance,improve rumen buffering capacity and fiber enzyme activity,and increase the concentration of blood calcium,mag⁃nesium and its metabolic factors.