Effects of replacement of fish meal by Antarctic krill meal on growth performance, immune indexes and muscle quality of Pelteobagrus fulvidraco

An 8-week feeding experiment was conducted to evaluate the effects of replacing fish meal (FM) with krill meal (KM) on the growth performance, serum immune indexes and muscle quality of Pelteobagrus fulvidraco initial body weight (10.51±0.13) g. Five experimental diets consisted of different proportions of FM that were replaced with KM, corresponding to dietary inclusion levels of 0% (KM0), 2.5% (KM2.5), 5% (KM5), 7.5% (KM7.5), and 10% (KM10). The results showed that there was no significant difference in growth performance, survival rate, intestinal amylase and lipase activities with the increase of the substitution proportion of krill meal. Compared with KM0 group, trypsin activity in each substitution group decreased significantly. Compared with KM0 group, the content of serum complement 3 in each substitution group increased significantly, and immunoglobulin M in KM5 group increased significantly. When the substitution level exceeded 5%, the activity of serum alkaline phosphatase decreased significantly. With the increase of the substitution ratio of krill meal, the muscle adhesiveness, springiness and gumminess decreased, the cohesiveness increased, and the hardness and chewiness increased first and then decreased. Compared with KM0 group, muscle adhesiveness, springiness and gumminess in KM10 group decreased significantly, and cohesiveness increased significantly. With the increase of the proportion of KM instead of FM, the content of total delicious amino acids and total non-essential amino acids in muscle hydrolyzed amino acids increased first and then decreased. In conclusion, the substitution of KM for FM has no negative effect on the growth performance, which can enhance immune function to a certain extent, and affect the muscle textural parameters and total delicious amino acids in the appropriate ratio.