| This study contained two trials. First, confirmed the security of this Radix Astragali Complex Chinese herbal medicinal additive by means of mice's feeding experiment, at last, the effect of radix Astragali Complex Chinese herbal medicinal additive on production performance, milk composition as well as blood parameters in dairy cows suffered from heat stress, and discussed the effect of anti-heat stress and action mechanism.Trial 1:The objective of this experiment was to prove whether or not Radix Astragali Complex (RAC) Chinese herbal medicinal additive would act a toxicandside-effect on dairy cows,40 healthy SPF Kunming mice (averaged 15-20g) were randomly assigned into control (group A) and treatment (group B, C and D), with 3 replicates per group and 3～4 mice per replicate. Mice were weighted before experiment, and fed diets added into 0.00,0.13,0.25 and 0.5g/10g Chinese herbal medicinal. The experiment lasted 40d, including 7d pre-feeding period and 33d test period. Observed mental state, breath, appetite, behavior, fur fineness and secretion of mice during the experiment period. At the end of the trial, mice were weighted and take the eyeball for blood and separate the serum, measure the serum ALT and AST activity. All the mice were killed and the viscera,especially the heart, liver, spleen, lung, kidney and thymus gland for further pathologically examined. Both thymus gland and spleen were weighed and calculated viscera index. The experimental results showed:a mice from group A, B, and D died, respectively, but no died from group C, the mice livability was 90%,90%,100% and 90% respectively. There were no abnormal conditions in metal state, breath, appetite, exercise state, fur fineness, feces, urine and tissues of all groups during experiment, and unusual secretion was not seen. Organization pathological change were not seen in all groups. Each group of mice weighted increased, thymus index and spleen index increased along with the Chinese medicine level increasing, the thymus index increased obviously (P<0.05), There was no difference (P>0.05) in serum ALT and AST activity in all groups. Results suggest that:Radix Astragali Complex (RAC) Chinese herbal medicinal additive have no toxicandside-effect on mice. It contributed to incremental weight gain and enhance viscera index, indicated that RAC promoted organism immunity increased.Trial 2:This article was conducted to study the effect of Radix Astragali Complex (RAC), Chinese herbal medicinal additive, on heat stressed dairy cow.12 multiparous Holstein cows, with similar parity, body weight and milk production, were allocated in a single factor design and were assigned randomly to control and treatment group with 6 replicates per group and 1 dairy cow per replicate. Cows in control group were fed basal diet, and in treatment group were fed basal diet supplemented with 200g RAC additives. The temperature and relative humidity of cowshed, feed intake, milk production, rectal temperature, respiratory frequency of dairy cattle were recorded daily during experiment. Serum cortisol, T4, heat shock protein 70, endotoxin, MDA, total SOD and GSH-Px activity were determined to evaluate the effect of RAC on blood biochemical index of heat stressed dairy cow. Rectal temperature and respiratory frequency did not differ between groups (P>0.05). Feed intake of treatment group was lower (P<0.05) than that of control group before week 2, after that it increased to the same level (P>0.05) as control group in week 3, and gradually exceed (P<0.05) the control group in week 4. Compared to control group, milk production of treatment group was higher (P<0.05) from week 5 to 6. Compared with control group fat percentage and milk protein in treatment group increased by 0.27% and 0.93% respectively, but not different (P>0.05) between the 2 groups. Compared with control group Lactose and milk solids in treatment group increased by 0.44% and 3.29% respectively, but not different (P>0.05) between the 2 groups. Compared with control group somatic cells (SCC) has the drop tendency, but not different (P>0.05), milk freezing point in each group was not different (P>0.05). Serum T4 level and total SOD activity in treatment group were significantly higher (P<0.05) than that of control group on d 40, but did not differ (P>0.05) before d 40. There was no difference (P>0.05) in serum cortisol level between groups. Serum GSH-Px activity in treatment group was 6.23% and 8.27% higher than that in control group on d 20 (P<0.05) and d 40 (P<0.01), respectively. No difference (P>0.05) were found on Serum GSH-Px activity between the 2 groups before d 20. Compared with control group, serum concentration of endotoxin and heat shock protein 70 in treatment group decreased by 20.53% and 6.27% on d 40, respectively, but not different (P>0.05) between the 2 groups on d 40. Serum MDA level of treatment group was the same (P>0.05) as that in control group before d 40, but lower (P<0.05) than that in control group on d 40. Results suggest that herbal additive may increase milk yield by increasing serum T4 level and antioxidase activity, decreasing endotoxin, heat shock protein 70 and MDA level.In conclusion, Radix Astragali Complex (RAC) Chinese herbal medicinal additive is a safety anti-heat stress additive. Results suggest that herbal additive may increase milk yield, alleviate heat stress effective, reduced the harm of heat stress certainly by increasing serum T4, cortisol level and antioxidase activity, decreasing endotoxin, heat shock protein 70 and MDA concentration. |
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