Changes in gonad of Nile Tilapia (Oreochromis niloticus) fed with crude extract of guava (Psidium guajava Linnaeus) leaves

Abstract

Tilapia is fraught with the problem of prolific breeding which usually leads to stunt growth thus making the fish undesirable for consumers. A56-days study was done to investigate the antifertility potential of P. guajava leaves extract on Oreochromis niloticus gonad, the sub-lethal concentrations were earlier reported to inhibit reproduction in the fish species. Oreochromis niloticus of mean weight 29.30±2.02-31.79±3.11 were divided into 6 groups replicated three times. Fishes were stocked in outdoor concrete tanks supplied with 450 litres of water. Six experimental diets (35% crude protein) containing varying sub-lethal concentrations of P. guajava leaf crude extract (0.0, 0.5, 1.0, 2.0, 4.0 and 8.0gkg^-1 diets) were formulated (representing O, A, B, C, D and E respectively; O serve as the control). The ovary and testis of fish fed control diet showed normal ovarian tissues and normal distribution of the testicular tissues. Mild atresia and reproduction in the oocytes were observed in the ovaries as the concentration of the crude extract increased from 0.5- 8.0gkg^-1, while in the testes mild to severe atrophy and cystic seminiferous tubules were observed. This study infers that, for sustainable growth of Tilapia culture, P. guajava could be used to solve the problem of prolific breeding, thus energy used in reproduction can be converted to growth.

Keywords: Crude extracts, atresia, atrophy, Psidium guajava Linnaeus and guava