HYPOPHYSATION IN Clarias gariepinus USING CRUDE PITUITARY GLAND EXTRACT OF BULL FROG (Ranas catesbiana)

Résumé

 Mature Clarias gariepinus ranging between 860-970g total body weight (TBW) were treated with crude pituitary gland extract obtained from the Bullfrog (Ranas catesbiana) at four treatment levels of two pituitaries, four pituitaries and six pituitaries per brood stock of mean weight 814+81.62g and Ovaprim® for control. Each treatment was replicated three times and the frog's weight ranged between 47.28-58.63g. The latency period before successful stripping was | 4hours with two pituitary hormone dosage, 12hours with four pituitaries and 9hours with six pituitaries. Eggs were incubated at a temperature that ranged from 26-27°C. Hatching was noticed after 24hours and was completed after 36hours of incubation. It was observed that the " fecundity varies with the dosage of administered pituitary. The highest number of egg yield was observed in (T2,) fishes administered with the four doses of pituitary gland (52168 + 3623) closely followed by (T1,) fishes administered with two doses of pituitary gland (46218 + 5142).The least fecundity was observed in (T3,) fish administered with six doses of pituitary gland (27360+4250). Percentage fertilization and hatching of the eggs were also highest in T2, (98%) and this was followed by the fishes in T1, having 98% fertilization and 70% hatching ratio. The fishes in T3, had the lowest value of 96% fertilization and 58% hatching. The fries produced were then reared for eight weeks and mortality observed was highest during their 2" week of life in all the three treatments. Fries produced in T2, (four pituitaries) was observed to have the highest survival rate (72.61%) followed by T1, with 33.62% survival rate and fr, with only 6.78% survival rate. Four pituitary gland treatments were found to be the most effective.