Effects Of Selenium And Microecological Agents On Growth Performance,Intestinal Health And Meat Quality Of Broilers

Selenium and microecological agents as feed additives are the hot spot of animal nutrition research at present.The previous research of our research group has shown that dietary supplementation of selenium can significantly improve the serum antioxidant capacity and selenium content of Linwu duck,and dietary supplementation of yeast selenium can improve the laying performance,egg quality and selenium content of eggs.The application effect of microecological agents in laying hens were also explored,but the combined effects of different selenium sources and microecological agents in broiler production are not clear.Therefore,the purpose of this experiment was to investigate the effects of selenium and microecological agents on growth performance,tissue selenium distribution,antioxidant performance,intestinal health,slaughter performance and meat quality of broilers,and to explore the combined effects of selenium and microecological agents on broiler production.A two-factor 2×2 completely random design was used in this experiment,which was divided into 4 treatment groups,each treatment group had 5 replicates,each replicate was 20 chickens.Based on the basic diet,In group I,0.2 mg/kg inorganic selenium(sodium selenite)was added;in group II,0.2 mg/kg organic selenium(yeast selenium)was added;in group III,0.2 mg/kg inorganic selenium(sodium selenite)and 0.5% microecological agent were added;in group IV,0.2 mg/kg organic selenium(yeast selenium)and 0.5%microecological agent were added.The experiment was divided into two feeding stages:0-35 days old and 35-70 days old,the total experimental period was 70 days.The results showed that:(1)There was no significant difference in growth performance between the supplementation of inorganic selenium(sodium selenite)and organic selenium(yeast selenium)in experimental broiler diets(P>0.05).The combined use of organic selenium and microecological agents can significantly reduce the feed to weight ratio of 0-35 days old broilers(P<0.01).The combined use of inorganic selenium and microecological agents had the tendency of increases the average daily gain of 35-70 days old broilers and reduce the feed to weight ratio.From the whole period of consideration,the combied use of selenium and microecological agents in the form of organic selenium was better than inorganic selenium.(2)Compared with inorganic selenium,dietary supplementation of organic selenium can significantly increase the selenium content in broiler tissues(P<0.01).Compared with two selenium sources used separately,the selenium content in pancreas,chest muscle,leg muscle and serum of broiler was significantly increased when selenium and microecological agents were used in combination(P<0.01).(3)There was no significant difference in broiler serum T-AOC,SOD,GSH-Px activity and MDA content when dietary supplementation of inorganic selenium and organic selenium(P>0.05).Compared with two selenium sources used separately,the combined use of selenium and microecological agents can significantly improve the activity of T-AOC and GSH-Px(P<0.05),and the combined use of organic selenium and microecological agents had the best effect.(4)Compared with inorganic selenium,organic selenium can significantly reduce the depth of duodenal crypt and increase the height of jejunal villus in broilers(P<0.05).The combination of inorganic selenium and microecological agents can significantly reduce the depth of duodenal crypt and increase the ratio of villus to crypt and the height of jejunum and ileum villus in Broilers(P<0.05)The results showed that the levels of Bacteroides were higher than those of inorganic selenium,but the differences were not significant(P>0.05).Barnesiella was significantly higher than that of inorganic selenium at the level of cecum(P<0.05).The combination of selenium and microecological agents had significant effects on the number of OTUs in ileum and cecum and Chao in broilers 1.The Bacteroides were higher in index and gate level than that of the two selenium sources alone.The combination of inorganic selenium and microecological agents significantly increased the level of xanthomonadaceae in ileum.The combination of organic selenium and microecological agents significantly increased the level of barnesiella in cecum compared with inorganic selenium(P<0.05).(5)The dressed weight rate and eviscerated yield rate of broilers fed with organic selenium were significantly higher than that of inorganic selenium(P<0.05),but the combined use of selenium and microecological agents had no significant effect on slaughter performance and immune organ index(P>0.05).(6)Compared with inorganic selenium,dietary supplementation of organic selenium can significantly improve the tenderness of broiler muscles,reduce the b*value and L*value of leg muscles at 24 h and the L*value of leg muscles at 48 h after broliers slaughtered(P<0.05).The combined use of organic selenium and microecological agents can significantly improve the water holding capacity,tenderness,a*value of chest muscles and leg muscles at48 h and 24 h,and reduce the L*value of leg muscles at 48 h(P<0.05).In conclusion,organic selenium can significantly increase tissue selenium deposition,improve duodenal tissue morphology,and improve slaughter performance,the combined use of selenium and microecological agents can improve growth performance of broilers,increase tissue selenium deposition,improve body antioxidant ability,and improve intestinal health and meat quality to a certain extent.The combined use of organic selenium and microecological agents has a better effect.