Effects of selenium-enriched fly maggot powder on cadmium content,microelement,metal transporter gene expression,and intestinal structure in cadmium-exposed carp

LIU Gang; LI Da-ji

doi:10.13557/j.cnki.issn1002-2813.2024.20.011

Abstract：The aim of this experiment was to study the effects of selenium-enriched fly maggot powder on the growth performance,Cd content,microelement,metal transporter gene expression,and intestinal structure of cadmium-exposed carp.A total of 360 healthy carp with body weight of about 40 g were randomly divided into four groups with six replicates per group and 15 carp per replicate,control group,Cd exposure group(1 mg/L),sodium selenite treatment group(0.25 mg/kg selenium)and selenium-enriched fly maggot powder group(30％selenium-enriched fly maggot powder containing 527 μg/kg selenium).The experiment lasted for 4 w.The results showed that the final weight,weight gain,and specific growth rate of carp in experimental groups were significantly lower than those in control group(P＜0.05),and the feed coefficient was significantly higher than that in control group(P＜0.05).The weight gain rate,specific growth rate and fatness of sodium selenite group and selenium-enriched fly maggot powder group were significantly higher than those of Cd exposure group(P＜0.05).The protein efficiency of selenium-enriched fly maggot powder group was significantly higher than that of Cd exposed group(P＜0.05).The concentrations of Cd in liver,intestine,muscle and kidney of carp in selenium-enriched fly maggot powder group and sodium selenite group were significantly lower than those in Cd exposure group(P＜0.05),and those in selenium-enriched fly maggot powder group were significantly lower than those in sodium selenite group(P＜0.05).The concentrations of zinc,copper and iron in most organs of selenium-enriched fly maggot powder group and sodium selenite group were significantly higher than those of Cd exposure group(P＜0.05).The expressions of zinc transporter 1(Znt1)and copper transporter 1(CTR1)in intestinal tract of sodium selenite group and selenium-enriched fly maggot powder group were significantly higher than those of Cd exposure group(P＜0.05),and the expression of divalent metal transporter 1(DMT1)in intestinal tract of selenium-enriched fly maggot powder group was significantly higher than that of Cd exposure group(P＜0.05).The intestinal villus length of selenium-enriched fly maggot powder group was significantly higher than that of Cd exposure group(P＜0.05).The results show that dietary supplementation of sodium selenite and selenium-enriched fly maggot powder could effectively inhibit the visceral Cd deposition of Cd-contaminated carp,increase the content of trace elements,activate the expression of metal transporter gene,and improve the intestinal structure.The effect of selenium-enriched fly maggot powder group is the best.