Effects Of Four Functional Feed Additives On Growth Performance,Lipid Metabolism,Non-specific Immunity And Health Of Liver And Intestine Of Anguilla Marmorata

A 60-day feeding trail was conducted to evaluate effects of four functional feed additives on growth performance,lipid metabolism,non-specific immunity,histomorphology of liver and gut and intestinal bacteria of Anguilla marmorata.Five isoenergetic and isolipid diets were formulated:group 1(basal diet + 200 mg/kg curcumin),group 2(basal diet +1000 mg/kg sodium butyrate),group 3(basal diet+1000 mg/kg fructooligosaccharide),group 4(basal diet +1000 mg/kg compound of Chinese herbal medicine extracts)and group 5(basal diet).Each diet was randomly fed to triplicate groups of fish with initial body length of 41.54 ± 0.83 cm and initial body weight of 167.67 ± 13.33 g.The research achievement could provide the basic information for the four feed additives in A.marmorata formulated feed.The main results are as follows:1.Effects of four functional feed additives on growth performance and digestive enzyme activities of A.marmorataWGR,SGR and FCR of A.marmorata were significantly increased by adding four functional feed additives(P<0.05)except for CF(P>0.05)respectively.There were different effects of four feed additives on digestive enzyme activities of A.marmorata.The intestinal protease activity was not significantly influenced by four feed additives(P>0.05),while intestinal AMS activity was improved by adding four feed additives.And 1000 mg/kg fuctooligosaccharide significantly enhanced intestinal AMS activity(P<0.05).In addition,intestinal LPS activity of A.marmorata was significantly improved by fructooligosaccharide and compound of Chinese herbal medicine extracts(P<0.05).2.Effects of four functional feed additives on lipid metabolism of A.marmorataDifferent feed additives had different effect on lipid metabolism.The level of TC,TG and LDL-C of liver were decreased by adding 200 mg/kg curcumin(P>0.05).Sodium butyrate decreased the level of TC and TG in liver(P>0.05),besides it significantly decreased the content of LDL-C of liver and GOT activity of serum(P<0.05).Similarly,the level of TC and TG of liver were decreased by adding 1000 mg/kg fructooligosaccharide(P>0.05),besides the content of LDL-C of liver was significantly decreased(P<0.05).Compound of Chinese herbal medicine extracts significantly increased the level of HDL-C in serum(P<0.05).Meanwhile,it decreased the level of TC,TG and LDL-C in liver(P>0.05).Above all,200 mg/kg curcumin has no significant effect on lipid metabolism of A.marmorata(P>0.05).The ability of lipid metabolism of A.marmorata was significantly enhanced by 1000 mg/kg sodium butyrate,1000 mg/kg fructooligosaccharide and 1000 mg/kg compound of Chinese herbal medicine extracts(P<0.05),besides sodium butyrate was benificial to keep liver health.3.Effects of four functional feed additives on non-specific immunity of A.marmorataFour functional feed additives all can significantly improved non-specific immunity of A.marmorata.Curcumin significantly enhanced SI,GPx activity and T-AOC in gill(P<0.05),and enhanced CAT activity and T-AOC in serum(P>0.05).Sodium butyrate significantly improved T-AOC of gill(P<0.05)and improved CAT activity and T-AOC of serum(P>0.05).SI,CAT and ACP activity in serum,SOD activity in gill were significantly increased by adding 1000 mg/kg fructooligosaccharide(P<0.05).Compound of Chinese herbal medicine extracts significantly improved LYZ activity and T-AOC of serum(P<0.05)and improved SOD activity and T-AOC of gill and ACP activity of serum(P>0.05).4.Effects of four functional feed additives on histomorphology of liver and gut of A.marmorataFour functional feed additives have no significant effect on histomorphology of liver.Each group had the normal liver cell with clear borders and centered nucleus.Four feed additives all significantly improved histomorphology of gut(P<0.05).Curcumin significantly increased the quantity of villus and muscular thickness of midgut(P<0.05).Fructooligosaccharide significantly increased the quantity of villus,diameter and muscular thickness of midgut(P<0.05).In a word,both of them have more positive effect on histomorphology of gut than the others.Sodium butyrate significantly increased muscular thickness of midgut(P<0.05).Compound of Chinese herbal medicine extracts significantly increased the quantity of villus of midgut(P<0.05).5.Effects of four functional feed additives on intestinal bacteria community of A.marmorataFour functional feed additives have large influence on intestinal bacteria community of A.marmorata.The diversity of intestinal bacteria in hindgut was decreased by adding four functional feed additives compared with the control group.The control group had the highest shannon index 3.08,while the least shannon index 2.32 appeared in group 2(1000 mg/kg sodium butyrate).The study revealed that the dominant bacteria of hindgut were Proteobacteria and Firmicutes.And four functional feed additives increased the number of Proteobacteria,meanwhile decreasing the number of Firmicutes.Analysing from the level of genus of bacteria,the number of Lactococcus was increased,while the number of Clostridium and Lactobacillus decreased.Thus,feed additives regulated the constitution of hindgut bacteria of A.marmorata.Cluster Analysis showed that group 1 and group 3 clustered together.It reflects that they have the most similar bacteria community,which is consistent with the result of histomorphology of gut.