Alteration of growth performance, meat quality, antioxidant and immune capacity of juvenile Litopenaeus vannamei in response to different dietary dosage forms of zinc: Comparative advantages of zinc amino acid complex

Abstract

An 8-week feeding trial was conducted to investigate the effects of different dietary dosage forms of zinc on growth performance, meat quality, antioxidant and immune capacity of juvenile Pacific white shrimp, Litopenaeus vannamei. Four isonitrogenous and isolipidic diets were formulated to contain different dosage forms of zinc, the control diet (no-supplemented zinc), I-Zn diet (120 mg kg−1 zinc from zinc sulfate), M-Zn diet (60/60 mg kg−1, zinc sulfate/zinc amino acid complex = 1:1) and Availa-Zn diet (60 mg kg−1 zinc from zinc amino acid complex), respectively. A total of 480 shrimp juveniles with initial weight 1.84 ± 0.02 g were randomly divided into four diets with four replications, each replication consisted of 30 shrimp. The results revealed that shrimp fed the M-Zn diet had significantly higher percent weight gain (PWG), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER) and protein retention efficiency (PRE) than those fed the other diets. The significantly higher concentration of glucose (GLU) in hemolymph was observed in shrimp fed the M-Zn diet. Shrimp fed the diets supplemented with zinc amino acid complex had significantly lower values of drip and thawing losses of whole shrimp or muscle compared to those fed the control and I-Zn diets, which indicated that shrimp fed the diets supplemented with zinc amino acid complex had a better water-holding capacity. Moreover, shrimp fed the Availa-Zn diet had significantly higher the activities of alkaline phosphatase (AKP), acid phosphatase (ACP) and lysozyme (LZM) in hepatopancreas than those fed the control and I-Zn diets. Meanwhile, shrimp fed the M-Zn and Availa-Zn diets showed an up-regulation of expression levels of Cu-Zn sod, akp, acp and lzm in hepatopancreas. Principal component analysis (PCA) and multivariate correlation analysis demonstrated that shrimp fed the experimental diets exhibited significant variations and shrimp fed the M-Zn diet showed better growth response and meat quality. These findings could contribute to provide scientific evidences into the business application of zinc amino acid complex.