Histology of gonads in Tilapia zillii (Gervais) fed neem (Azadirachta indica) leaf meal diets.

Neem (Azadirachta indica) leaf meal (NLM) was added to a basal diet (350g crude protein and 18.5MJ gross energy/kg diet) at 0, 0.5, 1.0, 1.5 or 2.0 g/kg diets and fed to mixed-sex Tilapia zillii for 60 days to evaluate the effects on histology of the testes and ovaries. Male T. zillii fed 0g NLM/kg diet showed normal testicular tissues; and no pathological lesions occurred. Fish fed 0.5g NLM/kg diet showed alteration in testicular architecture and cystic seminiferous tubules. Fish fed 1. 0g NLM/kg diet showed severe testicular atrophy. Fish fed 1.5g NLM/kg diet exhibited cystic seminiferous tubule and atrophy of tissue. Fish fed 2.0g NLM/kg diet showed severe tissue atrophy, sperm cells disintegration and necrosis. Female T. zillii fed with control diet (0g NLM/kg diet) showed normal ovary histology and no pathological lesions were observed. Typical bilateral lobes of the ovaries were evident and with normal olive green colour of ovaries. Fish fed 2.0g NLM/kg diet revealed ovarian colour change. There was evidence of hydropic degeneration, ruptured follicle, granulomatous inflammation in the insterstitium and necrosis. Histological observations of testes and ovaries in T. zillii fed high dietary NLM levels revealed that neem leaves may be effective as sterility-inducing agents as they were destructive to testes and ovaries tissues.