Investigation into the Impacts of Varied Batches of Stripped Eggs on the Reproductive Success of Clarias gariepinus

Abstract

This study was conducted at the hatchery complex of Akwa Ibom State University to investigate the effects of different batches of stripped egg on reproductive performances of Clarias gariepinus. Nine brood stocks of Clarias gariepinus (six males and 3 females) with average body weight of 2.3kg and 64.2 cm where carefully selected for the study. Six matured males were euthanized for the removal of testis without hormonal inducements. The milt collected from the six males were pooled together and divided into 12 portions each diluted with 2mL of normal saline solution. Three female brood stocks where separately induced with hormone at single dosage of 0.5ml/kg body weight and allowed for a period of 10 hours before stripping. Stripping of eggs from each brood stock where in four batches, each batch measured 50g and labeled A, B, C and D. 3g of eggs containing approximately 2000 oocytes (eggs) where measured out from each batch and mixed with the diluted milt and incubated in a 2 x 1 x 10cm3 of water in a concrete pond at temperature of 26oC in three replicates. The result revealed that the reproductive performances considered in this study decreased as the batches of stripped eggs increased from 1 ̶ 4 batches. The first batch of stripped eggs produced 87.69 ± 0.42, 97.06 ± 0.84, 84.29 ± 1.05 percentage fertilization, hatchability and survival rate respectively, while the least batch of stripped eggs (batch 4) produced the least value of fertilization 50.33 ± 1.67, 31.93 ± 4.94 hatchability and survival rate value of 42.69 ± 0.61.  Therefore, from the above result, the least batch of stripped eggs should not be used for fertilization because the unhatched or dead eggs has a negative effect on the fertilized eggs including fry at the hatchery level.