BENEFICIAL EFFECTS OF TWO Lactobacillus plantarum STRAINS ON EGG HATCHABILITY AND LARVAL SURVIVAL OF AFRICAN CATFISH (Clarias gariepinus)

Abstract

This study evaluated the effect of two strains of Lactobacillus plantarum on egg hatchability and larval survival during artificial propagation of Clarias gariepinus. Each of the test bacteria were added to the incubating water in a 6-litre circular bowl at a concentration of 2×103 and 2×106 cfu/L respectively, while incubating bowl without test bacterial inclusion served as control. Two grammes of fertilized eggs were incubated in triplicate bowls for each experimental group under room temperature. The percentage hatchability of the incubated eggs and the survival of the resulting larvae on third and tenth day of hatching, as well as the microbiological analysis of 10 day old larvae in all experimental groups were determined. All data were statistically analysed using one-way analysis of variance (ANOVA) while Duncan Multiple Range test was employed to separate means among experimental groups. The results of this study showed that percentage hatchability ranged from 69.85% to 71.12%, and was found to be insignificantly differed among the experimental groups. The larvae from test bacterial treatment groups had significantly (p<0.05) higher percentage survival after third day of hatching than the control groups, although no lactobacilli was detected in the guts of larvae after tenth day of hatching in all experimental groups. It can be concluded that incubation of gariepinus eggs in water inoculated with adequate quantity of the test bacteria did not contribute to egg hatchability but had profound effects on larval survival during their first few days of life