Influence of 17α-Methyl Testosterone Infused Diets on Growth and Tissue Integrity in Oreochromis niloticus (Linnaeus, 1758): A Laboratory Study

In this study, the effects of varying concentrations of 17α-methyl testosterone (17α-MT) in the diet on the growth performance, survival rate, and histopathology of Nile tilapia - Oreochromis niloticus (Linnaeus, 1758) were investigated. Four different hormone doses, 0 mg/g (control), 0.5 mg/g, 0.7 mg/g, and 0.9 mg/g were administered with the diet of O. niloticus for 120 days. Growth performance, as measured by the increase in total length (12.98 ± 1.26 cm) and total weight (18.99 ± 2.36 g), was highest in O. niloticus receiving 0.9 mg/g 17α-MT diet. The total weight (TW) increase was significantly more pronounced than that observed in total length (TL). In the average growth of length (31.13%) and weight (43.16%), the 0.7 mg/g 17α-MT diet had the highest percentage. However, the hormone treatments had no serious effect on the survival rates of the fish in the study. The histopathological changes in the liver showed sinusoid dilation, vacuolization of hepatocytes, enlargement of central veins, and hemorrhages with increased hormone doses. In the kidney, treatment of 0.7 mg/g and 0.9 mg/g of the 17α-MT diet resulted in changes in the renal tubules, necrosis, degenerated kidney tubules, and dilation of the glomerulus. The present findings show that 17α-MT treatments notably enhance the overall length, weight, and general growth performance of O. niloticus. Therefore, carefully structured experiments employing suitable hormone doses in fish feed may prove advantageous for the commercial cultivation and conservation of this popular fish species in the country.