The liver and gonads play very important roles in the lives of organisms. The liver is the centre of metabolism while the gonads are important in production of sex cells necessary for the continuity of any species. Their importance has attracted several investigations carried out on them as well as on the blood, skin and kidney exposed to xenobiotics. These include the works of Ayotunde (2006); and Ada et al. (2011). Abnormalities in gonads were investigated in natural habitat of whitefish by Bernet et al. (2004) in Lake Thun. Some abnormalities recorded include adhesions/fusions to the peritoneal wall and the lateral trunk musculature, asymmetry, atrophy, compartmentations, constrictions and hermaphroditism. Stentiford et al. (2003) investigated the histopathological alterations in selected organs and tissues of three species of estuarine fish (Platichthys flesus, Pomatoschistus minutus and Zoarces viviparus), captured from four British estuaries (the Tyne, Tees, Mersey and Alde) differently impacted by contaminants. Sampson et al. (2000) opined that flatfish (Pleuronectes platessa) are in close contact with sediments and are thus exposed to xenobiotics stored in the sediments and were observed to alter the histology of their liver, kidney and gonads in Mersey Estuary. Some other investigations on xenobiotics on the general health of fish were carried out by Visoottiviseth et al. (1999), Babatunde et al. (2001); Agbon et al. (2002); Kori-Siakpere et al. (2007); Ayotunde et al. (2010a, b) and Ada et al. (2012a, 2012b). Kamanga et al. (2002) stated that under natural conditions, reproduction is influenced by environmental conditions. Ghanbahadur and Ghanbahadur (2012) stressed that the scientific management to obtain high yield of fish calls for adequate and in-depth study of gonadosomatic index which expresses the relative change in gonad weight to the percentage of body weight. According to these workers, this parameter is important in knowing the spawning periods of fish. The importance of liver and gonads cannot therefore be over emphasized. Oreochromis niloticus being the most culture fish species in Nigeria was investigated for the effects of some xenobiotics on the liver and gonads.

 

Figure 1 Hepatosomatic index of Oreochromis niloticus sub adults exposed to different concentrations of Glyphosate for 14 days

Figure 2 The hepatosomatic index of Oreochromis niloticus sub adults exposed to different concentrations of Gramoxone for 14 days

Figure 3 The Hepatosomatic index of Oreochromis niloticus sub adults exposed to different concentrations of Butachlor herbicidesfor 14 days. Means with different letters are significantly different

Figure 4 The hepatosomatic index of Oreochromis niloticus sub adults exposed to different concentrations of Artrazine for 14 days

Figure 5 Gonadosomatic index of Oreochromis niloticus exposed to different concentrations of Gramoxone for 14 days

Figure 6 Gonadosomatic index of Oreochromis niloticus exposed to different concentrations of Glyphosate for 14 days

Figure 7 Gonadosomatic index of Oreochromis niloticus exposed to different concentrations of Butachlor for 14 days

Figure 8 Gonadosomatic index of Oreochromis niloticus exposed to different concentrations of Atrazine for 14 days

Wany Y., Jaw C., Tang C., Lin T., and Chen Y., 1992, Accumulation and release of herbicide butachlor, thiobencarb, and chlomethxyfen by fish, clam, and shrimp, Bulletin of Environmental Contamination & Toxicology, 48(3): 474-480