Combined application of cortisol and thyroxin in the culture of larvae of freshwater catfish, Heteropneustes fossilis.

摘要

Newly-hatched larvae of freshwater catfish, H. fossilis, exposed to a mixture of thyroxine (T4; 2.6 ppm) and cortisol (F; 0.1 ppm) by immersion for 1 h exhibited earlier development than untreated control and larvae exposed to individual hormones. The yolk resorption and initial gut formation in the larvae were accelerated by the hormonal treatment. Larval survival after 30 days was maximum (81%) in the T4 + F group, followed by cortisol (56%), T4 (50%) and control (31%) (P < 0.001). The results indicate that hormone treatment enhanced gut development and digestive function, improving feed utilization, leading to better survival and uniform growth of larvae. These observations suggest that hormone therapy may have practical use in the culture of hatchery-reared freshwater catfish larvae.