Effect of zinc concentration on the growth performance of White leg shrimp, Litopenaeus vannamei Boone

Abstract

Awareness about healthy organic food is increasing, leading to research on contaminants/pollutants and their effect on aquatic fauna and mankind. The effect of zinc sulphate on the growth performance of White leg shrimp, Litopenaeus vannamei (Boone) was evaluated under six doses viz; 0.5, 1, 2, 4, 6, and 8 mg/l in in vitro study conducted from June to October 2021. The results revealed that higher doses of zinc sulphate showed toxicity against L. vannamei. The weight (3.12gm), length (8.95cm), weight gain per shrimp (4.11g), average daily weight gain (0.032), and specific growth rate (1.1g) were significantly (5%) lower at the higher dose (8mg/l) of zinc sulphate than control 11.73g, 16.22cm, 19.75g, 0.156g, and 2.20g respectively. With an increase in zinc sulphate dose from 0 mg/l in control to 8 mg/l, survival of shrimp decreased from 100 % to 7%. The Lethal concentration (LC50) for zinc sulphate treatments was recorded at 0.71 ppm for shrimp. The water quality parameter pH (7.17-8.09), dissolved oxygen (6.13-7.58mg/l), hardness (4000-4772mg/l), and total alkalinity (162-231mg/l) were in an optimum range. The variation in Nitrite- Nitrogen, Nitrate- Nitrogen and Ammonical-Nitrogen (0-0.018, 0-0.4, 0-0.018mg/l) were within a permissible range. Thus, the present study revealed that zinc had a negative potential effect on L. vannamei at higher concentrations and may lead to serious economic loss to farmers if ignored.