| The Chinese mitten crab(Eriocheir sinensis),commonly known as a river crab,is an important aquatic economic animal in China,whose characteristics of fighting and preying with each other in the living habits,resulting in low survival rate and unsatisfactory output in the culture environment of rice fields culture,ponds culture,and nets culture.Therefore,the monomer culture of mitten crab has gradually attracted people’s attention.In this study,a fully enclosed "Palace-style" monomer culture system with circulating water— "Crab Apartment",was used to study the effects of formula feed and frozen fish as the feeds on the growth performance,metabolism and intestinal microbes of Chinese mitten crabs.Moreover,we explore the possibility of factory farming of the mitten crabs and the evaluation of formula feed to completely replace frozen fish to provide some valuable experiences for the health of the river crab culture,feed additives and ecological environment protection.The main results are as follows:1.Under monoculture conditions,feeding Chinese mitten crabs with the formula feed and frozen fish for 180 days when the crabs shed their shells 4 times.The relationship between the body weight and the carapace length and width satisfies the regression curve equation y = a ln(x)+ b,which indicates that the crab can molt and grow under this condition.For gonadal development,the effect of the formula feed was significantly better than that of frozen fish(P<0.05).For muscle quality,Chinese mitten crabs have the following six factors: methionine(Met),lysine(Lys),glutamic acid(Glu),glycine(Gly),arginine(Arg),and proline(Pro).There were significant differences between amino acid groups(P<0.05).In terms of individual fatty acids,there are significant differences between palmitoleic acid(C16:1)and oleic acid(C18:1n-9)in ∑MUFA(P<0.05);in ∑PUFA,there are two types of fatty acids such as ARA and DHA.There are significant differences(P<0.05).2.The research on the complete replacement of the frozen fish with the formula feed,the results indicates that the SR of the crabs in the formula feed group is significantly higher than that in the frozen fish group(P<0.05);for the amino acid contents of the hepatopancreas,the difference between female and male crabs was obvious.Among them,the contents of ∑TAA,∑NEAA and ∑TEAA in the female crabs are significantly higher in the formula feed group than those in the frozen fish group(P<0.05).For male crabs,the content of ∑TAA in the frozen fish group is significantly higher than that in the formula feed group(P<0.05).For the determination of protein metabolism-related enzyme activity,the contents of aspartate aminotransferase(AST)and alanine aminotransferase(ALT)in the formula feed group are relatively increased.The two indicators in the formula feed group of the female crabs are significantly higher than those in the frozen fish group(P<0.05),while the levels of succinate dehydrogenase(SDH)in the formula feed group of the female crabs are significantly lower in the frozen fish group(P<0.05).In terms of protein metabolism gene expression,the expression levels of TOR,e IF4 G and Rag A/B are significantly different under the two feeding modes.The formula feed group compared with the frozen fish group is significantly increased(P<0.05),but the m RNA level of Akt was significantly decreased compared with the frozen fish group(P<0.05).3.The research on the effect of the intestinal microbiota of the crabs under the two feeding modes,the results show that through 16 S r RNA sequencing,84618 reads were measured for each sample,and the average sequence length was 253.08 bp.At the phylum level,the proportion of Bacteroidetes in the FF group was significantly higher than that in the CF group(P<0.05),and the proportion of Proteobacteria in the FM group was significantly lower than that in the CM group(P<0.05);at the genus level,the advantage genra of the four groups were almostly the same,but none had significant differences in the four groups(P>0.05);LEf Se analysis found that gender had no effect on the intestinal flora structure of Chinese mitten crabs,and the composition and structure of the intestinal flora in the formula feed group were better than those in the frozen fish group. |
PDF Full Text Request