EFFECT OF PAWPAW SEED ENRICHED MEALS ON HISTOLOGY OF GONADS IN MOZAMBIQUE TILAPIA (OREOCHROMIS MOSSAMBICUS)

Abstract

Pawpaw (Carica papaya) seed meal (P) was added to a basal diet (BD, commercial tilapia starterfeed) at 0, 0.5, 1.0, 5.0, 10.0 and 15.0 g/kg BD. The experimental diets were fed to sexually matured males and females (five each) (20-45g, 10 fish per replicate, five replicates per treatment) Oreochromis mossambicus for 60 days to evaluate the effects on histology of the gonads. Oreochromis mossambicus fed Og P /kg BD showed normal testicular tissues, with spermatozoa in seminiferous tubules and no lesions observed. Fish fed 0.5g P /kg BD showed some interstitial cells while, fish fed 1.0g P /kg BD showed, slight increased interstitial cells. Fish fed 5.0, 10.0 and 15.0g P/kg BD, showed signs of pathological changes as disintegration ofsperm cells and necrosis of the testicular cells were observed. Testis offish fed 10.0gP/kg BD showed an ova-testis and atrophy of the testicular tissues while, ovaries in fish fed with control diet (Og P /kg BD) showed normal ovarian histology. No pathological lesions were observed. Typical bilateral lobes of the ovaries were evident, with normal stages of developmental oocytes. Fish fed 1.0g P/kg BD revealed ovaries with developing oocytes and slight depletion of yolk particles. Ovaries in fish fed 5.0, 10.0 and 15.0g P/kg BD showed some signs of pathological changes. The ovaries had developing oocytes with depletion of yolk particles and some atretic oocytes. Histology of gonads in 0. mossambicus fed high dietary P revealed that pawpaw seeds could be an effective sterility-inducing agent.