The study on the reproductive indices and gonadal development of African catfish (Clarias gariepinus) fed shrimp based diet (SBD), chicken offal based diet (COBD) and coppens (commercial diet) was carried-out over a 22 weeks period in concrete tanks measuring 3.5 x 1.7 x 1.5 m3 (8.9 m3). Forty juveniles with average length of 9.15 ± 0.17 cm and weight of 20.00 ± 4.53 g were stored per group in triplicate, resulting in 360 juveniles in total. Fish were fed daily at 3% of their body weight through-out the duration of the experiment. The nutrient composition of the 3 nutrients differed significantly at p<0.05. The dissolved oxygen, temperature, pH and ammonia levels in the culture water with fish fed the 3 diets were within the required level for normal fish growth through-out the experiment. The gonadosomatic index (GSI) of the male C. gariepinus fed diet A (Coppens feed), diet B (SBD) and diet C (COBD) were 0.35 ± 0.03%, 0.41 ± 0.04% and 0.36 ± 0.02% respectively. Female C. gariepinus fed diet A, diet B and diet C had a mean GSI of 1.17 ± 0.26%, 0.88 ± 0.27% and 0.77 ± 0.06% respectively. The male gonad weight and GSI varied significantly between the treatment group fed coppens, shrimp based diet and chicken offal based diet (p<0.05), while female gonad weight and GSI did not vary significantly between treatment groups (p>0.05). The hepatosomatic index (HSI) of the male C. gariepinus fed diet A, diet B and diet C were 1.36 ± 0.07%, 1.18 ± 0.07% and 1.21 ± 0.06% respectively. Female C. gariepinus fed diet A, diet B and diet C had a mean HSI of 1.27 ± 0.09%, 1.20 ± 0.06% and 4.27 ± 0.38% respectively. The male and female HSI varied insignificantly between the treatment group at p>0.05. Fecundity was highest (3200 ± 717.90 eggs) in fish fed diet A, followed by fish fed diet B (2392 ± 749 eggs) and least in fish fed diet C (1973 ± 184 eggs). The mean fecundity varied significantly between the fish fed the 3 experimental diet at p<0.05. Normal arrangement of the oocytes, liver and testis was observed in fish fed COBD and SBD, just as in the case of the group fed coppens. Though coppens feed yielded better fecundity, the use of COBD and SBD is recommended for fish farmers in Nigeria. More researches should be carried out on using varying levels of chicken offals and shrimps in fish feed formulation.
Aspects of reproductive indices and enteroparasitic infestation of Clarias gariepinus (Burchell, 1822) in a tropical reservoir
