| Fishmeal is the primary protein source in aquatic feed due to its balanced amino acids composition and high digestibility.However,as the price of fishmeal continues to rise,it is urgent to seek new protein sources to decrease fishmeal inclusion in aquafeed.This study investigated the effects of replacing fishmeal with cottonseed protein concentrate and Clostridium autoethanogenum protein mixture,yeast culture,and fermented soybean meal on the growth performance,serum biochemical indices,intestinal and hepatopancreas histology of rainbow trout and yellow catfish.The findings will provide reference for the development of new protein sources and the preparation of low fishmeal diet for carnivorous fish.1.Effects of replacing fishmeal with the mixture of cottonseed protein concentrate and Clostridium autoethanogenum protein on the growth,nutrient utilization,serum biochemical indices,intestinal and hepatopancreas histology of rainbow trout(Oncorhynchus mykiss)This study investigated the potential of cottonseed protein concentrate(CPC)and Clostridium autoethanogenum protein(CAP)in the diet of rainbow trout(Oncorhynchus mykiss)by evaluating the effects of replacing fishmeal with CPC and CAP mixture on the growth performance,nutrient utilization,serum biochemical indices,intestinal and hepatopancreas histology.In a basal diet containing 200 g/kg fishmeal(CON),the mixture of CPC and CAP(1:1)was used to reduce dietary fishmeal to 150,100,50 and 0 g/kg,to form five diets with the same crude protein and crude lipid contents(FM-15,FM10,FM-5 and FM-0).Then,the five diets were fed to rainbow trout(35.00 ±0.05 g)for 8 weeks.The weight gain(WG)and feed conversion ratio(FCR)of the five groups were 258.72%,258.82%,249.90%,242.89%,236.57%,and 1.19,1.20,1.24,1.28,1.31,respectively.FM-5 and FM-0 groups showed significantly lower WG and higher FCR than the CON group(P<0.05).In terms of whole-body composition,such as moisture,crude ash and crude protein,no significant difference was observed among all the groups(P>0.05),except that significantly higher crude lipid content was detected in FM-0 group than that in the CON group(P<0.05).In FM-5 and FM-0 groups,protein efficiency,protein retention,intestinal protease activity and amylase activity were significantly lower than the CON group(P<0.05).Compared to the CON group,the serum contents of glucose and total cholesterol in FM-0 group as well as MDAin FM-5 and FM-0 groups were significantly increased,and catalase,superoxide dismutase and total antioxidant capacity were decreased(P<0.05).In intestine and hepatopancreas histology,the intestinal villus height in FM-5 and FM-0 groups and villus width in FM-0 group were decreased significantly(P<0.05),while no significant difference in hepatopancreas morphology was observed among all the groups except that some vacuolization were observed in FM-0 group(P>0.05).In summary,the mixture of CPC and CAP can effectively replace 100 g/kg fishmeal in a diet containing 200 g/kg fishmeal without adverse effects on the growth performance,nutrient utilization,serum biochemical,intestinal and hepatopancreas histology of rainbow trout.2.Effects of replacing fishmeal with yeast culture on growth performance,nutrient utilization,serum biochemical indices,intestinal and hepatopancreas histology of yellow catfish(Pelteobagrus fulvidraco)This study investigated the potential of yeast culture in the low fishmeal diet of yellow catfish(Pelteobagrus fulvidraco)by evaluating the effects of replacing fishmeal with yeast culture on the growth performance,nutrient utilization,serum biochemical indices,intestinal and hepatopancreas histology.In a basal diet containing 160 g/kg fishmeal(CON),yeast culture was used to reduce dietary fishmeal to 120,80,40 and 0 g/kg,to form five isonitrogenous and isolipidic diets(FM-12,FM-8,FM-4 and FM-0).Then,the five diets were fed to yellow catfish(3.00 ±0.10 g)for 8 weeks.The results showed that the weight gain(WG),protein efficiency rate and protein retention in FM-12 group and feed conversion ratio(FCR)in FM-12 and FM-8 groups were similar to those in the CON group(P>0.05).The WG in FM-8,FM-4 and FM-0 groups were significantly lower(-16.6%,-21.2%,and-26.1%),and the FCR in FM-4 and FM-0 group were significantly higher(+0.30 and+0.50)than the CON group(P<0.05).In terms of whole-body composition,such as moisture,crude ash,and crude protein,no significant difference was observed among all the groups(P>0.05),except a lower crude lipid content in the FM-0 group than that in the CON group(P<0.05).Compared to the CON group,aspartate aminotransferase and alanine aminotransferase activity and D-lactic acid content in the FM-0 group were significantly increased,and the total cholesterol content was significantly decreased(P<0.05).The activity of catalase,superoxide dismutase,alkaline phosphatase as well as the content of complement C3 and immunoglobulin M in the FM-12 and FM-8 groups were significantly increased,while the MDA content was significantly decreased(P<0.05).In terms of intestinal digestive enzyme activity,there were no significant differences in amylase and lipase activity among all the groups(P>0.05).The trypsin in FM-12 and FM-8 groups as well as the diamine oxidase in FM-4 and FM-0 groups were significantly higher than those in the CON group(P<0.05).In intestine and hepatopancreas histology,the intestinal villus height in FM-4 and FM-0 groups and villus width in FM-0 group were decreased significantly(P<0.05),while no significant difference in hepatopancreas morphology was observed among all the groups except obvious cell vacuolization in FM-0 group(P>0.05).In summary,yeast culture can effectively replace 40 g/kg fishmeal in a diet containing 160 g/kg fishmeal without adverse effects on the growth performance,nutrient utilization,serum biochemical indices,intestinal and hepatopancreas histology of yellow catfish.3.Comparison of two fermented soybean meals in the diets of yellow catfish(Pelteobagrus fulvidraco):Growth performance,serum biochemical indices,intestinal histology and resistance against bacterial infection.This study evaluated the effects of replacing fishmeal,soybean meal+soybean protein concentrate with two fermented soybean meals(FSM)on the growth performance,serum biochemical indices,intestinal histology and resistance against bacterial infection of yellow catfish.In a basal diet containing 160,230,and 60 g/kg fishmeal,soybean meal,and soybean protein concentrate,respectively(CON),then two fermented soybean meals(common fermented soybean meal A,and bacteriostasis fermented soybean meal B)were used to reduce dietary fishmeal to 80 g/kg(FM-8-A and FM-8-B),or reduce soybean meal and soybean protein concentrate to 170 and 0 g/kg(FM-16-A and FM-16-B),respectively.Then,the five diets were fed to yellow catfish(3.00 ±0.10 g)for 8 weeks.The weight gain(WG)in FM-8-A and FM-8-B groups were significantly lower(-16.0%,-19.5%),and the feed conversion ratio(FCR)were significantly higher(+0.30,+0.30)than those in the CON group(P<0.05).The WG in FM-16-B showed significantly higher WG and lower FCR than FM-16-A group(P<0.05),but both groups showed no significantly difference with the CON group(P>0.05).There was no significant difference in moisture,crude protein and crude lipid contents among all the groups(P>0.05).The crude ash,protein efficiency rate and lipid retention in FM-8-A and FM-8-B groups as well as protein retention in FM-8-A,FM-8-B and FM-16-A groups were significantly lower than those in the CON group(P<0.05).In terms of serum biochemical parameters,compared to the CON group,the alkaline phosphatase activity and immunoglobulin M content in FM-8-B and FM-16-B groups as well as the content of complement C3 in FM-8-B group were significantly increased,while the catalase and superoxide dismutase activities in the FM-8-A group were significantly decreased,and the MDA content in FM-8-A and FM8-B group was significantly increased(P<0.05).In terms of intestinal digestive enzyme activity,there were no significant difference in amylase and lipase activity among all the groups(P>0.05).The trypsin in FM-8-B,FM-16-A and FM-16-B groups was significantly higher,and the diamine oxidase activity in FM-8-A group and the content of D-lactic acid in FM-8-A and FM-8-B groups were also significantly higher than those in the CON group(P<0.05).In midgut histology,the intestinal villus height and muscle thickness in FM-8-A and FM-8-B groups were decreased significantly(P<0.05).After challenging against A.hydrophila,FM-8-B and FM-16-B groups showed significantly higher cumulative survival rate than the CON group(P<0.05).In summary,in a basal diet containing 160 g/kg fishmeal,fermented soybean meal replacing 80 g/kg fishmeal negatively affected on the growth performance,while the replacement of soybean meal+soybean protein concentrate with fermented soybean meal showed no adverse impact on growth performance of yellow catfish.Bacteriostasis fermented soybean meal could enhance resistance against bacterial infection of yellow catfish. |
PDF Full Text Request