Use of hCG hormone in the natural and artificial reproduction of Nile tilapia (Oreochromis niloticus)

This study aimed to develop a protocol to synchronize final oocyte maturation and oocyte collection in both natural (first experiment) and artificial reproduction (second experiment) of Nile tilapia. In the first experiment, 80 young females (1 year old), 40 old females (3 years old) and 75 young males were used and splitted into three different groups. Each group bred once by natural mating during 7 days. Each female received an injection of hCG (3 IU/g of female) or saline solution (control) just before being stocked with males. In the second experiment, we evaluated different doses (0.5, 1.5, 2.5 and 3.5 IU/g female), number of injections (1 or 2) and administration route (intracoelomic or intramuscular) of hCG hormone in 40 females for artificial reproduction by stripping. The use of hCG (3 IU/g of female) was not effective for synchronization of natural reproduction in Nile tilapia, and the negative effect of age on reproductive performance was not reversed by its use. In the second assay, the use of a single injection with lower doses of hCG (0.5 and 1.5 IU/g of female) resulted in 100% of spawned females in artificial reproduction.