丙二醇对围产期奶牛能量平衡及代谢产物的影响

为了研究丙二醇对围产期奶牛能量平衡、血液指标和肝脏甘油三酯与糖原含量的影响。选用24头体质量(683.1±14.9)kg、胎次(2.5±0.2)、上一泌乳期305d产奶量(7 339±18)kg和预产期(24.5±0.2)d的经产奶牛,随机分为4组,从分娩前19d开始分别在基础日粮中添加丙二醇0、150、300和450mL.d-1。结果表明:与对照组相比,添加丙二醇300和450mL.d-1,显著提高了奶牛分娩后7、21和35d体况评分,缓减了奶牛体质量下降程度,改善了奶牛分娩前14d和分娩后7、21和35d奶牛能量平衡(P<0.05)。300和450mL.d-1组奶牛分娩前14d和分娩后7、21和35d血糖和胰岛素浓度显著高于对照组(P<0.05)。300和450mL.d-1组奶牛分娩后7、21和35d血浆游离脂肪酸、β-羟丁酸和甘油三酯浓度显著低于对照组(P<0.05)。300和450mL.d-1组奶牛分娩后7、21和35d肝脏甘油三酯含量显著低于对照组(P<0.05),但分娩后7、21和35d肝脏糖原含量显著高于对照组(P<0.05)。结果提示在日粮中添加丙二醇能够减少肝脏脂肪沉积,加强葡萄糖异生作用,改善奶牛能量平衡,适宜添加量为300mL.d-1。

Effects of Propylene Glycol on Energy Balance, Blood Parameter, Concentration of Glucose and Adipose in the Liver during Peripartum Period in Dairy Cows

The objective of this study was to observe the effects of propylene glycol on energy balance,blood parameter,concentration of glucose and adipose in the liver during peripartum period in dairy cows.Multiparous Holstein dairy cows with similar body weight((683.1±14.9)kg),lactation number(2.5±0.2),corrected milk yield in last lactation((7 339±18)kg) and expected calving date((24.5±0.2)d) were allocated into four treatments at random.Graded levels(0,150,300 and 450 mL·d-1) of propylene glycol were supplemented in the four treatments from day 19 prepartum.The results showed that body condition score at 7,21 and 35 d postpartum increased,body weight loss from 7 to 35 d postpartum reduced,energy balance at 14 d prepartum and 7,21 and 35 d postpartum was improved significantly by the 300 and 450 mL·d-1 treatment compared with 0 mL·d-1 treatment(P<0.05).Cows receiving 300 and 450 mL·d-1 propylene glycol had a higher plasma glucose and insulin at 14 d prepartum and 7,21 and 35 d postpartum,lower plasma NEFA,β-hydroxybutyrate and triacylglycerol at 7,21 and 35 d postpartum than that of 0 mL·d-1 treatment(P<0.05).300 and 450 mL·d-1 propylene glycol supplementation decreased the contents of triacylglycerol in the liver and increased the contents of glycogen in the liver compared to 0 mL·d-1 propylene glycol treatment(P<0.05).The results indicated that propylene glycol supplementation was beneficial to peripartum cows in reducing the lipolysis,enhancing the gluconeogenesis and improving energy balance status,the optimum dose was about 300 mL·d-1.