Histological Changes in Gonads and Liver of Oreochromis niloticus (L.) Fed Crude Extract of Azadirachta indica Leaf

Abstract

Structural changes in the gonads and liver of Oreochromis niloticus fed sub-lethal concentration of crude extract of Azadirachta indica leaf was investigated. 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.  Each group was replicated three times. Fishes were stocked in out door concrete tanks (2x2x1.25 m) supplied with 450 litres of water. Six experimental diets (35% crude protein) containing varying sub-lethal concentrations of A. indica leaf crude extract (0.0, 0.5, 1.0, 2.0, 4.0 and 8.0 gkg-1 diets) were formulated (representing O, A, B, C, D and E respectively; O serves as the control). Fish were fed 3% body weight/day at two feeding instalments between 0900-0930 and 1700-1730 for 56 days. Ovary, testis and liver of fish fed control diet showed normal ovarian tissues, normal distribution of the testicular tissues and normal structure of the vein. Mild to severe necrosis and granulation of the interstitial tissue were observed in the ovaries as the concentration of the crude extract increased from 0.5 – 8.0 gkg-1. The testes showed mild to severe atrophy and cystic seminiferous tubules, while in the fish liver; increase in the number of rodlet cells and distortion of the vein walls were observed as the sub-lethal concentrations of the crude extract in the diets increased. Changes in the histology of the ovaries and testes showed the antiifertility potency of A. indica leaf, while changes in the liver histology revealed the sub-lethal toxicity effect of A. indica leaf all at moderate level of inclusions.