丙二醇对奶牛围产期血浆激素和肝脏糖异生限速酶的影响

EFFECTS OF PROPYLENE GLYCOL ON SERUM HORMONE AND KEY REGULATORY ENZYMES OF GLUCONEOGENESIS IN THE LIVER DURING PERIPARTUM PERIOD IN DAIRY COWS

研究了丙二醇对奶牛围产期血浆胰岛素及胰岛素样生长因子和肝脏糖原含量及糖异生途径限速酶活性的影响。选用24头体重(683.1±14.9)kg、胎次(2.5±0.2)、上一泌乳期305d产奶量(7339±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血糖、胰岛素和胰岛素样生长因子浓度(P<0.05)。奶牛分娩后7、21和35d奶牛肝脏糖原含量及糖异生途径限速酶活性显著高于对照组(P<0.05)。结果提示在日粮中添加丙二醇能够加强葡萄糖异生作用,适宜添加量为300mL·d-1。

The objective of this study was to investigate effects of propylene glycol on blood concentration of glucose,insulin and IGF-I,concentration of glucose and key regulatory enzymes of gluconeogenesis in the liver of dairy cows during peripartum period.Twenty-four 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（7339±18 kg） and expected calving date（24.5±0.2 d） were allocated into four treatments at random.Graded levels（0,150,300 and 450mL·d-1） of propylene glycol were supplemented in the four treatments from day 19 of prepartum.Results showed that cows receiving 300 and 450mL·d-1 propylene glycol had a higher plasma glucose,insulin and insulin-like growth factor-I at 7,21 and 35 d of postpartum.Under 300 and 450mL·d-1 propylene glycol supplementation the contents of glycogen and activities of key regulatory enzymes of gluconeogenesis in the liver increased compared to control（P0.05）.These findings in the present study indicated that propylene glycol supplementation was beneficial to peripartum cows in enhancing the gluconeogenesis and the optimum dose was about 300 ml per cow per day.