Role of thyroid hormone on the growth, survival and mineralization of Cirrhinus mrigala Hamilton

A laboratory feeding experiment on advanced fry of Cirrhinus mrigala was conducted to investigate the dietary effect of thyroid hormone on growth, survival and mineralization and to standardize the dietary doses of hormone for maximum growth. Four experimental diets incorporated with graded concentrations (0.005 to 5.0 ppm) of Thyroxine T4 with/without supplementation of calcium (75 ppm) and a control diet were evaluated. Thyroxine (T4) incorporated at 0.005 ppm level resulted in the highest growth and Survival of Cirrhinus mrigala advanced fry in both bore-well and calcium enriched water. The feed conversion efficiency was also found to be the maximum in the dose of 0.005 ppm thyroxine (T4). The carcass of fish administered 0.005 ppm T4 showed maximum protein content in both plain as well as calcium enriched water whereas there was not much variation in fat, carbohydrate and ash content of the fish. Determination of the growth in terms of mineralization amongst the treatments revealed insignificant variation.