Extraction Of Chlorogenic Acid From Honeysuckle And Influence On Antioxidant Functions In Beef Cattle Under Heat Stress

Honeysuckle is a kind of traditional Chinese medicine for clearing away heat and eliminating dampness. Modern research indicated that the active components as chlorogenic acid and flavonoid from flowers and leaves of Honeysuckle can help to remove superoxide ion free radicals in the body and protect tissues from oxidative stress damage. The main purpose of this study was to study the effect of chlorogenic acid extracts of Honeysuckle as additive on Heat-stress resistance and antioxidant functions in Beef Cattle, the experiment was divided into three parts,（1） Ultrasonic extraction process of chlorogenic acid from Honeysuckle and optimization of its parameters.（2） Effect of chlorogenic acid extracts of Honeysuckle on Heat-stress resistance in beef cattle.（3） Effect of chlorogenic acid extracts of Honeysuckle on antioxidant functions in beef cattle under heat stress.The first experiment, in order to screen the optimum conditions of extraction of chlorogenic acid from Honeysuckle by ultrasonic method, the extraction conditions（including ultrasonic power, ultrasonic time, solvent concentration, extraction temperature, ratio of solid to liquid） of the extraction rate of chlorogenic acid were preliminarily selected through the single factor experiment, and two levels were obtained in each factor. And then the parameters of the extraction process of chlorogenic acid in Honeysuckle were determined by using the orthogonal test（L827） for further screening. The results showed: the optimum ultrasonic extraction parameters of chlorogenic acid from Honeysuckle were ethanol by 70%, solid-liquid ratio by 1:35, ultrasonic by 30 min, ultrasonic power by 300 w and ultrasonic temperature by 70 ℃.The second experiment, this study was conducted to investigate the effects of Honeysuckle extract on antioxidant function and skeletal muscle morphology of beef cattle under hot environment. Twenty healthy Jinjiang yellow cattle with [（360±20） kg] were random Ly divided into 4 groups with 5 heads per each group. The control group was fed basic diets, and three Honeysuckle extract preparation groups were fed basic diets supplemented with 0.2%, 0.4% and 0.6% Honeysuckle chlorogenic acid extracts respectively. All cattle were fed under high temperature and humidity environment in summer, and the preliminary trial period lasted for 10 days, the positive trial period lasted for 60 days. The results showed as follows, high temperature and humidity environment in summer caused heat stress of beef cattle, and the average temperature humidity index（THI） in house was above 79. Compared with control group, body temperature in 0.2% and 0.6% groups were significantly declined on days 40（P<0.05）, but no difference was noticed between control and 0.4% group（P>0.05）. Compared with control group, breathing frequence in 0.6% group was significantly declined during 21⁴0 d and 41⁶0 d（P<0.05）, in 0.2% group was significantly declined during 41⁶0 d（P<0.05）. Serum contents of triiodothyronine（T₃） and thyroxine（T₄） in experimental groups were increased, but serum cortisol（COR） content was declined compared with control group. And meanwhile, serum activities of superoxide dismutase（SOD）, glutathione peroxidase（GSH-Px） and total antioxidant capacity（T-AOC） in experimental groups were enhanced, but serum content of malondialdehyde（MDA） was decreased. Moreover, the concentration of blood glucose, total protein and albumin in Honeysuckle extract groups are increased significantly（P<0.05）, and the contents of total cholesterol, high density lipoprotein and low density lipoprotein in 0.6% group were significantly lower than them in control group（P<0.05）, but no difference was noticed about the contents of blood urea nitrogen and triglycerides（P>0.05） among the treatment groups. These results indicated that dietary supplementation of Honeysuckle extracts improved antioxidant capability, Promoting protein and energy metabolism, Regulating fat metabolism, relieved stress reaction of beef cattle, and the effect of 0.2% and 0.6% Honeysuckle extracts group on them are better.The third experiment, In order to further study the mechanism of the extract of honeysuckle on heat resistance of beef cattle, Six cattle from control and 0.2% Honeysuckle extracts group were slaughtered and their muscle and liver samples were isolated to determine the antioxidant indexes and the relative expression of antioxidant enzymes. The results showed, MDA levels of liver in Honeysuckle extracts group were decreased by 48.53%（P<0.05）, but the activity of T-AOC were enhanced（P<0.05）compared with control. No difference was noticed about the activity and m RNA expression of Cu/Zn-SOD and GSH-Px between two groups. These results indicated that dietary supplementation of Honeysuckle extracts improved antioxidant capability of muscle and liver, but did not influence the gene expression of antioxidant enzymes.