Effects of dietary dosage forms of copper supplementation on growth, antioxidant capacity, innate immunity enzyme activities and gene expressions for juvenile Litopenaeus vannamei

Abstract

The experiment was conducted to evaluate the effects of different dietary dosage forms of copper supplementation on growth performance, hematological characteristics, antioxidant capacity, immune responses and gene expressions related to innate immune of juvenile Pacific white shrimp Litopenaeus vannamei. Three isonitrogenous and isolipidic diets were formulated to contain three dosage forms of copper: copper sulfate (Diet I-Cu), copper sulfate + copper amino acid complex (1: 1, Diet M-Cu) and copper amino acid complex from Availa^®Cu100 (Diet Availa-Cu), respectively. 360 Pacific white shrimp juveniles (initial weight 1.86 ± 0.03 g) were randomly allocated in 12 tanks corresponding to quadruplicate tanks of the three dietary treatments, and the 8-week feeding trail was conducted. The results indicated that percent weight gain (PWG) and specific growth rate (SGR) in shrimp fed M-Cu diet were significantly higher than that fed I-Cu diet. Survival, feed efficiency (FE), protein efficiency ratio (PER) of shrimp were not significantly different between all treatment groups. High contents of total protein (TP) and glucose (GLU) were found in shrimp fed the diet containing M-Cu, whereas contents of cholesterol (CHOL) and triacylglycerol (TAG) in shrimp fed M-Cu diet were significantly lower than that in I-Cu diet group. In hemolymph, shrimp fed M-Cu diet had high activities of phenoloxidase (PO), alkaline phosphatase (ALP) and acid phosphatase (ACP). While, Cu/Zn superoxide dismutase (Cu/Zn SOD), ceruloplasmin (CP) and lysozyme (LZM) in hemolymph were not significantly affected by different dietary dosage forms of copper. High activities of Cu/Zn SOD, ALP, ACP and LZM in hepatopancreas were observed in shrimp fed M-Cu diet. Shrimp fed diet supplemented with Availa-Cu showed a significantly higher gene expression levels of Cu/Zn sod, alp, acp and lzm in hepatopancreas than that fed I-Cu diet. This study indicated that copper amino acid complex was more effective than copper sulfate to improve growth performance and enhance antioxidant ability and innate immune system.

Keywords: Antioxidant capacity; Copper source; Gene expression; Growth performance; Innate immunity; Litopenaeus vannamei.