Comparative Difference Between the Effects of Lhrh-a, 17 ¡- Methyltestosterone Pellets and Hcg on Reproductive Performance of Mugil cephalus

The present study was conducted to investigate the effect of LHRH-a, 17 ·- m ethyltestosterone pellets a nd HCG on reproductive performance of Mugil cephalus. The fish were injected in captivity out of the spawning season by different hormones. Luteinizing Hormone Releasing Hormone analogue (LHRH- a) p ellets and Human Chorionic Gonadotropin H ormone (HCG) w ere tested to induce the maturation in the f emales f ive m onths earlier t han the b reeding s eason. Tow doses of LHRH-a (10 0 and 200 µg) were used during the quiescent p eriod (March, A pril and May). Gonadosomatic index, eg g diameter and its frequency distribution were affected positively on both doses (higher in case of 200 µg). The effect of both d oses w as sim ilar on the short ter m, b ut wa s sig nificantly different o n the long term. C ompared to the co ntrol, a f urther egg diameter was observed in case of 100 µg, while t wo further egg diameters were observed i n case of 200 µ g. Also t wo doses of HCG (5,000 a nd 1 0,000 I U) were used f or the same purpose. The control group fish s pawned in O ctober, while i n c ase of 100 µg LHRH-a, the fish s pawned July and i n c ase of 200 µg LHRH-a, the fish spawned in late June. According to males, four sexual hormones (LHRH-a, HCG, 17 ·- methyltestosterone (MT) and 17 ·- methyltestosterone-cholesterol (MT- Ch.)) were t ested t o i nduce milt production. LHRH-a s howed the highest induction on short term (a fter one and t wo weeks). On the other hand, 17 ·- methyltestosterone-cholesterol showed the highest induction potency o n long term (after five weeks). H CG showed the lowest induction among all of the tested hormones, while 17 ·- m ethyltestosterone showed a good effect, just c ame after its mixing wi th cho lesterol. Mature males could be easily supplied on demand out of the b reeding s eason.

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