Influence of Brooders’ Age on the Reproductive Performance of African catfish (Clarias gariepinus Burchell, 1822) Reared in Tank System

Abstract

This study investigated the influence of brooder’s age on the reproductive performance of African catfish. The brooders were obtained and bred in an indoor hatchery using standard hypophysation protocol with ovaprim hormone. The fish seed were raised in tarpaulin tanks until they were used as brooders at the ages 6-, 9-, 12-, and 15-month-old. Three randomly selected brooders were weighed before ovaprim hormone was administered to the females (0.5ml/Kg), and the males were euthanized for milt collection. The fish were examined for reproductive qualities, including egg size before and after fertilization, sperm volume, count, and colour, and the results were compared among the brooders of different ages. Weight of the ovary and estimated number of eggs increased significantly (P<0.05) with an increase in the age of the brooders. The highest ovary weight of 62.84±0.02g and the no of eggs of 940.26±0.11 were both recorded in 15-month-old brooders. The egg size before and after fertilization increased significantly with an increase in the brooder’s age. The highest sperm motility, 96.80±0.60% was observed in 15-month-old, and was only significantly different from 92.02±0.70% observed in 6-month-old brooders. Both sperm volume and spermatocrit were similar between 12 and 15-month-old brooders but were significantly different from 6 and 9-month-old brooders. The fertilization rate, hatched eggs, and larvae survival increased significantly with an increase in age; both 6 and 9-month-old brooders had survival of <50%. The study established that brooder’s age influenced the reproductive performance, and a brooder African catfish of 12 months and above is recommended.