Application Of Fermented Soybean Meal And Yeast Culture In The Diets Of Hybrid Snakehead(Channa Argus×Channa Maculata)

Protein source is the key factor to determine the feed cost.Fish meal is the best protein source in aquatic feed,but due to the high price,it is a research focus to develop new protein sources to reduce fish meal inclusion in aquatic feed.This study investigated the effects of replacing fish meal with yeast culture(enzymolysis soybean meal as substrate)and fermented soybean meal on the growth,serum biochemical parameters and intestinal health of hybrid snakehead(Channa argus × Channa maculata),and compared the effects of yeast culture replacing chicken meal,meat and bone meal and soybean protein concentrate.The results could provide theoretical basis for the development of low fish meal feed and for the application of new protein sources.1 An Evaluation of Replacing Fish Meal with Fermented Soybean Meal in Diet of Hybrid Snakehead: Growth,Nutrient Utilization,Serum Biochemical Parameters and Intestinal HealthThis study investigated the effects of fermented soybean meal(FSM)as a substitute for fish meal(FM)on the growth,serum biochemical parameters and intestinal health of hybrid snakehead.Five iso-proteinic diets were formulated with FSM inclusion to decrease dietary FM from 350 g/kg(the control diet)to 300,250,200 and 150 g/kg,referring to CON,FM-30,FM-25,FM-20 and FM-15,respectively,then fed to hybrid snakehead with initial body weight of 6.5±0.1 g for 60 days.The weight gain,feed intake and intestinal protease activity decreased,and feed conversion ratio increased in FM-25,FM-20 and FM-15 groups when compared to the CON group(P<0.05).The apparent digestibility coefficients of dry matter and crude protein,the protein efficiency and retention,serum total cholesterol content and the intestinal muscle thickness in FM-20 and FM-15 groups and the villus height in all FSM groups,were significantly lower than those in the CON group(P<0.05).Intestinal microbiota analysis indicated that the main microorganisms included Proteobacteria,Firmicutes and Actinobacteria.At the genus level,Plesiomonaswas the dominant genus with the highest relative abundance in the FM-20 group.In summary,in a diet containing 350g/kg FM,FSM can successfully replace 50 g/kg dietary FM without negative effects on growth performance,nutrient utilization,serum biochemical indexes and intestinal health of hybrid snakehead juvenile.2 An Evaluation of Replacing Fish Meal with Yeast Culture in Diet of Hybrid Snakehead: Growth,Nutrient Utilization,Serum Biochemical Parameters and Intestinal HealthThis study investigated the effects of yeast culture(YC)as a substitute for fish meal on the growth,serum biochemical parameters and intestinal health of hybrid snakehead.In a basal diet containing 250 g/kg fish meal,0,29.5,59.0 and 88.5 g/kg fish meal were replaced by 0,40,80,120 g/kg yeast culture protein to form four diets containing 250.0,220.5,191.0 and 161.5 g/kg fish meal(CON,YC-40,YC-80 and YC-120),respectively.The four diets were fed to hybrid snakehead with initial body weight(9.2±0.1 g)for 70 days.The results showed that there were no significant differences in weight gain,feed conversion ratio,protein efficiency rate,protein retention and lipid retention among the three groups of CON,YC-40 and YC-80 groups(P>0.05).The weight gain,protein efficiency rate,protein retention and lipid retention in YC-120 group were significantly lower than those in CON group(P<0.05).No significant differences in body indexes and whole body proximate composition were detected among all the groups(P>0.05).In terms of serum biochemical parameters,superoxide dismutase activity and total antioxidant capacity in YC-40 and YC-80 groups were significantly increased,total cholesterol content in YC-120 group was significantly decreased when compared to the CON(P<0.05).In terms of foregut morphology,YC-120 group showed significantly lower muscle thickness and villus height than the control(P<0.05),but there was no significant difference in villus width among all the groups(P>0.05).Intestinal microbial analysis showed that the intestinal microorganisms in each group were mainly composed of Firmicutes,Spirochaetota,Proteobacteria and Actinobacteria.The relative abundance of Brevinema in YC-120 group was significantly higher than that in CON group(P<0.05).In conclusion,in the basal diet containing 250.0 g/kg fish meal,80 g/kg yeast culture could replace 59.0 g/kg fish meal without adverse effects on growth performance,nutrient utilization,serum biochemical indices and intestinal health of juvenile hybrid snakehead.3 An Evaluation of Replacing Chicken Meal,Meat and Bone Meal and Soy Protein Concentrate with Yeast Culture in Diet of Hybrid Snakehead: Growth,Nutrient Utilization,Serum Biochemical Parameters and Intestinal HistologyThis study investigated the effects of replacing chicken meal(CM),meat and bone meal(MBM)and soy protein concentrate(SPC)with yeast culture(YC)on the growth performance,serum biochemical parameters and intestinal histology of hybrid snakehead.In the basal diet containing fish meal(250 g/kg),chicken meal(120 g/kg),meat and bone meal(80 g/kg)and soy protein concentrate(80 g/kg),80 g/kg YC was used to replace 80 g/kg chicken meal,meat and bone meal or soybean protein concentrate(CON,YC-80-CM,YC-80-MBM and YC-80-SPC).Then,the four diets were fed to hybrid snakehead with initial body weight(9.2±0.1 g)for 70 days.The results show that there were no significant differences in weight gain,feed conversion ratio,feed intake and protein efficiency among the three groups of CON,YC-80-CM and YC-80-MBM groups(P>0.05).However,YC-80-SPC group presented significantly higher weight gain,feed intake and lipid retention than the CON group(P<0.05).No significant differences in body indexes and whole body proximate composition were found among all the groups(P>0.05).In terms of serum biochemical indices,the total cholesterol content and total protein content of YC-80-CM and YC-80-MBM groups,and the superoxide dismutase activity and total antioxidant capacity of YC-80-MBM and YC-80-SPC groups were significantly lower than those of the CON group(P<0.05).There were no significant differences in intestinal protease activity and amylase activity among all the groups(P>0.05).In terms of foregut morphology,the villus height and muscle thickness in YC-80-CM and YC-80-MBM groups showed no significant differences with the CON(P>0.05),while YC-80-SPC group had significantly higher villus height and muscle thickness than the CON(P<0.05).In conclusion,in the basal diet containing meat and bone meal(80 g/kg),soy protein concentrate(80 g/kg)and chicken meal(120 g/kg),the replacement of soy protein concentrate(80 g/kg)with the same amount of yeast culture significantly improved the growth performance,serum antioxidant capacity and intestinal tissue structure of hybrid snakehead.The replacement of 80 g/kg meat and bone meal,or chicken meal with yeast culture did not affect the growth performance,serum biochemical indices,intestinal enzyme activity and intestinal structure.