Effects of amino acid chelate micronutrients on physiology and intestinal flora of Litopenaeus vannamei fed with cottonseed protein concentrate (CPC) replacement of fishmeal in diet

Concentrated cottonseed protein (CPC) serves as an ideal protein replacement for fish meal in diets, though excessive use can adversely affect aquatic life. Organic trace element replacements can sustain the growth and metabolic functions of Litopenaeus vannamei, aiding in the conservation of high-quality protein resources such as fish meal. The purpose of this experiment is to explore the impact of substituting fish meal with CPC as a protein source, along with substituting amino acid trace element chelates, on the growth, immune antioxidant capacity, and intestinal microbiota of Litopenaeus vannamei. Four experimental diets were formulated: the control group FM (no CPC substitution, supplemented with inorganic trace elements), the inorganic trace element group C0 (CPC substituted for 40 % fish meal, supplemented with inorganic trace elements), and the experimental group C1 (CPC substituted for 40 % fish meal, amino acid trace element chelates substituted for 40 % inorganic trace elements). and C2 (CPC replacing 40 % fish meal, amino acid chelated trace minerals replacing 60 % inorganic trace minerals). Each group had three replicates. At the end of a 10-week feeding trial, the research results are as follows: Group C2 had significantly higher crude protein and crude lipid contents compared to Group C0 (P < 0.05). In comparison to Group C0, the FM group demonstrated much higher activities of CuZn-SOD, GPX, and CAT (P < 0.01), group C0 exhibited notably lower activities compared to Groups C1 and C2 (P < 0.05). Relative abundances of major intestinal microbiota species in Groups C1 and C2 underwent significant changes. Compared to Groups C0 and C2, the expression levels of lipid metabolism genes were much higher in Group C1 (P < 0.05). In fish meal replacement diets with CPC, using 40 % amino acid chelates can mitigate adverse effects of plant protein and enhance shrimp lipid metabolism, immune antioxidants, and intestinal flora.