Comparative evaluation of copper sulfate and tribasic copper chloride on growth performance and tissue response in Pacific white shrimp Litopenaeus vannamei fed practical diets

Abstract

Abstract Two trials were conducted to evaluate the response of Pacific white shrimp Litopenaeus vannamei to dietary copper sulfate containing 25.45% copper (Cu) and tri-basic copper chloride (TBCC) containing 58.81% Cu. The basal diet used in each trial was primarily composed of fishmeal, soybean meal, corn starch, and whole wheat and was formulated to contain approximately 10 mg Cu kg − 1 . In trial 1, two sets of diets, one supplemented with copper sulfate (6, 12, and 24 mg Cu kg − 1 ) and the other with TBCC (6, 12, and 24 mg Cu kg − 1 ) were conducted in a clear water recirculating system (N = 4; 0.31 g initial weight) for 8 weeks. In trial 2, shrimp (N = 4; 0.39 g initial weight) was fed the same six diets as trial 1 for 6 weeks in an outdoor green water recirculating system. At the conclusion of the trials, final mean weight, percent weight gain, final biomass, feed conversion ratio (FCR), and survival were determined. There were no significant effects from dietary copper levels on final mean weight, final biomass, FCR, and survival. There was a significant effect of the source of Cu on tissue levels, with shrimp fed TBCC having lower tissue Cu levels in both trials. Copper analysis of select tissues (carapace, hepatopancreas, and hemolymph) of shrimp from trials 1 and 2 indicated some significant difference among the treatments. In trials 1 and 2, when the tissue concentrations are pooled across dietary levels for each copper source, copper levels of the tissues from shrimp fed TBCC were significantly lower than those of shrimp fed diets supplemented with copper sulfate. Application of a slope ratio approach using linear regression of log 10 transformed tissues copper concentration on analyzed copper level indicated a lower bioavailability from TBCC compared with copper sulfate. The results of the present study demonstrate that TBCC is an effective copper source.