亚急性瘤胃酸中毒对奶山羊血浆异常代谢产物及生化指标的影响

本试验通过递增饲粮非纤维性碳水化合物与中性洗涤纤维比(NFC/NDF)方式诱导奶山羊发生亚急性瘤胃酸中毒(SARA),旨在探讨SARA诱导过程中奶山羊血浆组胺(HIS)、脂多糖(LPS)含量及生化指标的变化。选取4只体况良好、体重接近的泌乳期萨能奶山羊,依次饲喂NFC/NDF为1.40、1.79、2.31、3.23的4种饲粮,每种饲粮饲喂15 d(为1组),前12 d为适应期,后3 d为采样期。酶联免疫吸附测定(ELISA)法检测血浆中HIS、LPS的含量,生化分析仪测定血浆生化指标。结果表明:1)当饲粮NFC/NDF由1.40递增至3.23时,成功诱导奶山羊处于SARA状态。2)在诱导SARA发生过程中,随着饲粮NFC/NDF增加,血浆HIS和LPS含量增加,NFC/NDF为3.23时显著高于NFC/NDF为1.40时(P0.05)。3)随着饲粮NFC/NDF增加,血浆免疫球蛋白M(Ig M)、免疫球蛋白A(Ig A)、免疫球蛋白G(Ig G)含量无显著变化(P0.05);血浆肌酐(CREA)、D-乳酸(LD)含量及肌酸激酶(CK)、谷草转氨酶(AST)、二胺氧化酶(DAO)活性无显著变化(P0.05);血浆γ-谷氨酰转移酶(γ-GT)活性呈升高趋势,NFC/NDF为3.23时显著高于其他各组(P0.05);血浆尿素氮(UN)含量降低,NFC/NDF为1.40时显著高于其他各组(P0.05);血浆碱性磷酸酶(ALP)活性升高,NFC/NDF为3.23时极显著高于其他3组(P0.01);血浆游离脂肪酸(FFA)含量先升高后降低,且在NFC/NDF为2.31时极显著高于其他各组(P0.01);血浆β-羟丁酸(β-HB)含量降低,NFC/NDF为1.40时呈极显著高于其他各组(P0.01)。结果提示,随着饲粮NFC/NDF递增,血浆中HIS和LPS含量显著增加,引发了机体炎症反应,加重了瘤胃上皮的损伤和SARA病情,激发奶山羊免疫活化状态;诱导SARA发生过程中,血浆生化指标有不同程度的变化,提示SARA期间奶山羊处于应激状态,引发了肝功能损伤。

Effects of Subacute Ruminal Acidosis on Plasma Abnormal Metabolites and Biochemical Indexes of Dairy Goats

Using the method of increasing dietary non-fiber carbohydrate/neutral detergent fiber (NFC/NDF) to induce subacute ruminal acidosis (SARA) of dairy goats for the purpose of investigating the changes of lipopolysaccharide (LPS) and histamine (HIS) contents,and biochemical indexes in plasma.Four healthy Saneng dairy goats with similar body weight were selected.Goats were fed 4 diets with different NFC/NDF (1.40,1.79,2.31 and 3.23,respectively) in order.Each diet was fed for 15 days as 1 group,the first 12 days were for adjustment period,and the last 3 days were for sampling period.Plasma LPS and HIS contents were detected with the method of enzyme linked immunosorbent assay;plasma biochemical indexes were detected with biochemical analyzer.The results showed as follows:1) SARA was successfully inducted when NFC/ NDF reached the level of 3.23 since 1.40.2) The contents of HIS and LPS in plasma were both increased with the gradual increase of dietary NFC/NDF during SARA induction,and 3.23 NFC/NDF group was significantly higher than 1.40 NFC/NDF group (P＜0.05).3) With the increase of dietary NFC/NDF,the contents of immunoglobulin M (IgM),immunoglobulin A (IgA) and immunoglobulin G (IgG) in plasma were not significantly changed (P＞0.05);the contents of creatinine (CREA) and D-lactic acid (LD) and the activities of creatine kinase (CK),aspartate aminotransferase (AST) and diamine oxidase (DAO) were not significantly changed (P＞0.05);plasma γ-glutamyl transpeptidase (γ-GT) activity tended to be increased,and 3.23 NFC/NDF group was significantly higher than other groups (P＜0.05);plasma urea nitrogen (UN) content was decreased,and 1.40 NFC/NDF group was significantly higher than other groups (P＜0.05);plasma alkaline phosphatase (ALP) activity was increased,and 3.23 NFC/NDF group was significantly higherthan other groups (P＜0.01);plasma free fatty acid (FFA) content was firstly increased and then decreased,2.31 NFC/ NDF group was significantly higher than other groups (P＜0.01);plasma β-hydroxybutyric acid (β-HB) content was decreased,and 1.40 NFC/NDF group was significantly higher than other groups (P＜0.01).The results indicate that the contents of HIS and LPS in plasma are both significantly increased with the gradual increase of dietary NFC/NDF,which lead to inflammatory reaction in dairy goats,aggravate illness of SARA,and active immune reaction;different changes of biochemical indexes in plasma are observed,which suggests that dairy goats is in a state of stress during SARA period,and liver damage is caused.