Optimization Of Extraction Parameters Of Saposhnikovia Divaricate Polysaccharide And Its Effect On Antioxidant Capacity Of Broilers

The purpose of this experiment was to optimize the extraction process of Polysaccharide from Saposhnikovia Divaricate which varieties native to Daqing.In order to explore the application of SDP in broilers,the effects of Saposhnikovia Divaricate Polysaccharide(SDP)on antioxidant indexes of broilers were studied under healthy state and Dexamethasone(DEX)induced oxidative stress.The effects of Liquid/Solid,Ultrasonic Temperature and Ultrasonic Time on the extraction rate for SDP were studied.The experiment was designed by a single factor combined with response surface methodology.By matching the mathematical model of three factors on the extraction rate of SDP,it was found that the order of three factors affecting the extraction rate of SDP was: Liquid/Solid > Ultrasonic Temperature > Ultrasonic Time.The optimized model finally determined the optimal extraction rate of SDP as follows: Liquid/Solid 41:1,Ultrasonic Temperature 60 ℃,Ultrasonic Time 59 min.The theoretical extraction rate was 1.036% and the result was verified by practice.In order to study the effect of SDP on the antioxidant performance of broilers,240 1-dayold AA broilers were randomly divided into five groups according to the principle of similar weight,with five replicate in each group and eight in each replicate,respectively: blank group(CON),SDP group(SDP),oxidative stress model group(DEX),high dose SDP oxidation model group(SDPHD),medium dose SDP oxidation model group(SDPMD)and low dose SDP oxidation model group(SDPLD).CON and DEX groups were fed with basic diet.After 14 days of age,SDP,SDPHD,SDPMD and SDPLD groups were added with 1000,1000,500 and 100mg/kg SDP respectively.In DEX,SDPHD,SDPMD and SDPLD groups,6mg/kg BW DEX was injected intramuscularly on the morning of the 21 st day to induce the formation of acute oxidative stress.At 4,8,12,16 and 24 hours after DEX injection,one chicken in each group was randomly selected for slaughter.The results show that:(1)Effect of SDP on performance of BroilersThe addition of SDP in diet had a certain effect on the performance of broilers.The feeding of SDP had no effect on the average daily gain and average daily feed intake of broilers(P>0.05).Although the average daily gain showed an increasing trend with the increase of SDP feeding dose,it did not show significant difference(P > 0.05).However,SDP significantly reduced the feed weight ratio of broilers(P < 0.05).(2)Effect of SDP on antioxidant performance of BroilersSupplementary feeding of SDP increased the activity of antioxidant enzymes in broilers.Compared with CON group,SDP group the Total Antioxidant Capacity(T-AOC)and Glutathione Peroxidase(GSH-Px)activity in pectoral muscle,Superoxide Dismutase in myocardium,T-AOC and GSH-Px activity in liver,T-AOC,GSH-Px,SOD and CAT activity in serum of SDP group were significantly increased(P < 0.05).In addition,supplementary feeding of SDP the content of MDA in breast muscle,liver and serum of broilers decreased significantly.(3)Effect of SDP on antioxidant performance of broilers with acute oxidative stress induced by dexamethasone.After DEX injection,except that the CAT activity in myocardium was not significantly(P >0.05),the antioxidant indexes in other tissues decreased significantly;MDA level was significantly increased(P < 0.05).The results showed that intramuscular injection of DEX successfully induced oxidative stress in broilers.The antioxidant capacity of broilers fed with different doses of SDP was significantly affected.In SDPHD group,except that the cat activity in myocardium was not significantly different from that in DEX group(P > 0.05),the antioxidant enzyme activity in other tissues was significantly higher than that in DEX group,and the MDA content was significantly lower than that in DEX group(P < 0.05).In SDPMD group,SOD activity in breast muscle,GSH-Px and SOD activity in myocardium,T-AOC,SOD,CAT activity in liver,and activities of SOD and CAT in serum were significantly higher than those in DEX group.The contents of MDA in chest muscle,myocardium and serum were significantly lower than DEX group(P < 0.05)In SDPLD group,GSH-Px activity in myocardium,T-AOC and SOD activity in liver,and SOD activity in serum were significantly higher than DEX group.the contents of MDA in myocardium and serum were significantly lower than those in DEX group(P < 0.05).According to the results of trend analysis,the antioxidant index of CON group is used as the parent sequence,and the other groups are used as subsequences to solve the grey correlation degree.And the correlation degree is normalized,and the sorting result is: SDPMD group > SDP group > SDPHD group > DEX group > SDPLD group.The results showed that the changing trend of antioxidant indexes in the SDPMD group was more consistent with that in the CON group,which was better than that in the SDP and SDPHD groups.The two-way ANOVA of time and polysaccharide dosage showed that the interaction of modeling time and polysaccharide dosage could significantly affect the activities of cat enzyme in breast muscle and SOD enzyme in liver of broilers(P < 0.05)The results showed that in the above indicators,with the increase of polysaccharide feeding dose,the enzyme activity was increased and the time of oxidative stress was shortened.Considering the results of significance and trend analysis,it is considered that there is the best dosage of SDP in the dose range of 500 ～ 1000 mg/kg.Conclusion: by optimizing the extraction process,the extraction rate of SDP was the highest under the conditions of liquid material ratio 41:1,ultrasonic temperature 60 ℃,and ultrasonic time 59 min,and the extraction rate was 1.036%.SDP can improve the activity of T-AOC,SOD,GSH-Px,and cat in serum and some tissues(pectoral muscle,myocardium,and liver)of broilers under healthy conditions and reduce the content of MDA.Under oxidative stress,feeding SDP can effectively alleviate the decrease of antioxidant enzyme activity and the increase of MDA content caused by stress to protect the body from oxidation.Considering the results of significance and trend analysis,it is recommended that the appropriate additive amount of SDP is 500～1000 mg/kg.