中草药制剂对热应激奶牛泌乳性能、抗氧化能力及免疫功能的影响

为探讨复合中草药制剂对热应激奶牛泌乳性能、抗氧化能力及免疫功能的影响,选择产奶中后期的健康中国荷斯坦奶牛20头,按泌乳时间和产奶量相近的原则均分为A、B、C和D 4组。A组为对照组,饲喂基础日粮;B、C和D组分别在每头牛的基础日粮中添加50,100和150 g/d水平的复合中草药制剂。每天测定产奶量,在试验的第1(添加复合中草药制剂之前)、20和40天逐头采集血样,测定不同剂量复合中草药制剂对热应激奶牛血淋巴细胞凋亡率、血液抗氧化酶GSH-Px、CAT基因及血淋巴细胞凋亡相关基因Bcl-2、p53表达水平的影响。结果表明,B、C和D组的日产奶量较对照组分别提高了20.26%(P<0.05),24.20%(P<0.05)和16.98%(P>0.05);乳中体细胞数较对照组分别降低了21.68%(P<0.05),29.88%(P<0.05)和24.22%(P<0.05);奶牛血液抗氧化酶GSH-Px、CAT基因的表达水平分别比对照组提高了5.00%(P>0.05),13.00%(P<0.05),6.00%(P>0.05)和5.00%(P>0.05),16.00%(P<0.05),3.00%(P>0.05);奶牛血淋巴细胞平均凋亡率分别比A组降低了18.20%(P>0.05),17.86%(P>0.05)和12.51%(P>0.05);奶牛血淋巴细胞Bcl-2在20,40 d时均极显著高于A组,全期的平均水平分别比对照组高出105.00%(P>0.05),113.00%(P>0.05)和57.00%(P>0.05);p53基因的表达水平在20,40 d时均极显著低于A组,全期的平均水平分别比对照组降低了24.00%(P>0.05),28.00%(P>0.05)和20.00%(P>0.05)。试验组中,C组奶牛的日产奶量、体细胞数、血液抗氧化酶活性、淋巴细胞凋亡相关基因表达等指标要优于B、D组;而血液淋巴细胞凋亡率指标为B组最好。说明复合中草药制剂能有效改善热应激奶牛的泌乳性能、抗氧化能力及免疫功能,且在本试验条件下,每头牛日粮中添加100 g/d水平的效果要优于50及150 g/d水平。

Effect of Chinese herbal medicine on milk production,antioxidant capacity and immunity of dairy cows

The effect of compound Chinese herbal medicine on milk performance, antioxidant capacity and immunity of dairy cows was studied in 20 healthy mid to late lactation Chinese Holstein cows. Based on lactation time and milk yield, cows were divided into four equal size groups (A, B, C and D). Group A (control) was feed the base diet only (no herbal medicine), whereas group B, C and D were feed the basal diet supplemented with 50, 100 and 150 g/d of the Chinese herbal medicine, respectively. The milk yield for each cow was measured daily. Blood samples for each cow under heat stress conditions were collected on the 1st, 20th and 40th day following implementation of treatments to determine apoptosis rate of lymphocytes, GSH-Px, and gene expression of CAT and lymphocyte apoptosis related gene, Bcl-2, p53. Cows in group B, C and D produced 20.26%, 24.20% and 16.98% more milk than those in group A (P<0.05), respectively. The somatic cell counts in milk from group B, C and D were 21.68%, 29.88%and 24.22% (P<0.05) lower than that group A, respectively. The mean level of GSH-Px and CAT gene expression in group B, C and D was greater than that in group A by 5.00% (P>0.05), 13.00% (P<0.05), 6.00% (P>0.05) and 5.00% (P>0.05), 16.00% (P<0.05), 3.00% (P>0.05), respectively. The apoptosis rate of lymphocyte in cows from group B, C and D were 18.20% (P>0.05), 17.86% (P>0.05) and 12.51% (P>0.05) lower than those in group A, respectively. The expression level of Bcl-2 in group B, C and D was 105.00% (P>0.05), 113.00% (P>0.05) and 57.00% (P>0.05) higher than that in group A, respectively. Additionally, the expression level of p53 gene in groups B, C and D were 24.00% (P>0.05), 28.00% (P>0.05) and 20.00% (P>0.05) lower than that in the control group, respectively. The gene expression level of Bcl-2 and p53 was significantly higher in groups (B, C and D) than that in control group after 20 and 40 days. Within the groups receiving Chinese medicine, milk yield, somatic number, antioxidase activity and expression level of lymphocytic apoptosis related genes were higher in group C than other groups, while the apoptosis rate of lymphocyte in group B was highest. This study suggested that compound Chinese herbal medicine can improve milk performance, antioxidant capacity and immunity of dairy cattle under heat stress.