Strain comparison on reproductive performance, growth and survival in two wild <i>Clarias Gariepinus</i> (Burchell 1822) and their reciprocal hybrids

Abstract

A strain comparison experiments was carried out in wild Clarias gariepinus with the aim of evaluating the reproductive performance, (in terms of percentage fertility and hatchability) growth and survival for choice of strain in selective breeding. Live samples of wild C. gariepinus collected from River Argungu, Kebbi state (KB) and Eleyele dam, Oyo state (OY), Nigeria were crossbred and mated in pure parental and reciprocal crosses generating four mating combinations (generic crosses) replicated three times in completely randomized design (CRD) manner. The F₁ generations were reared indoor for 56 days. The hybrids revealed higher characters compared to the progeny of pure parental groups in fertilization rate (84.000±0.270%; 78.265±0.135% compared to 88.400±0.130%; 71.465±0.265%), hatching (77.305±0.405%;72.235±0.465% compared to 80.995±0.025%; 64.555±0.615%) and survival of larvae (100.000±0.000%; 98.582±1.418% compared to 98.840±0.581%; 73.371±0.157%). On the other hand, fertilization and hatching rate among the hybrids and the pure crosses were statistically significant (P<0.05). Similarly, significant difference (P<0.05) was observed between the two reciprocal hybrids. However, the hybrid crosses showed intermediate characters between the pure crosses in mean weight gain (MWG), specific growth rate (SGR) and survival of fingerlings. Though the crosses of pure Oyo species displayed significantly higher value in MWG (5.583±0.058g) and SGR (10.319±0.051g) than other groups, fingerling survival (73.371±0.157%) was found to be lowest. The growth parameters like MWG (4.884±0.001g) and SGR (10.231±0.130g) of the hybrids of Oyo fingerlings were found to be higher than pure Kebbi crosses, while survival (100.000±0.000%) of hybrid of Kebbi fingerlings were higher than pure Kebbi (98.840±0.581%). Therefore, this is considered as heterosis (hybrid vigour) for the hybrids they have achieved better traits either one of the pure groups. Intra-specific cross of female wild C. gariepinus from Kebbi and male wild C. gariepinus from Oyo (KB♀ × OY♂) be practiced for optimum performance used in commercial production. This will ensure high fertility, hatchability, growth and survival rate.

Key words: Clarias gariepinus, growth, reproductive performance, Strain comparison, survival.