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Viability of Different Strains of <i>Lactobacillus fermentum</i> in Feed and Effects on Growth Performance of <i>Clarias gariepinus</i> Fry
Abstract
Globally, aquaculture has developed significantly; however, poor performance at larvae stage is still a challenge. The use of antibiotics has post-application effects in aquaculture hence the demand for eco-friendly alternatives. The Lactobacillus fermentum strains BCS27 and F4S8 isolated from fermented maize and cassava respectively were supplemented in six isonitrogenous (55% protein) fry diet in three different concentrations (3x107, 6x107 and 9x107cfu/ml/100g) with a positive (T0) and negative (AT0) controls. The strain BCS27 were included in these concentrations to give treatments LF1T1, LF1T2, LF1T3 while strain F4S8 represented treatments LF2T1, LF2T2, LF2T3. Three-day old Clarias gariepinus larvae (0.005g) were fed to satiation for eight weeks in a completely randomized design. The highest mean weight gain (MWG) of 0.4116±0.02g and specific growth rate (SGR) of 0.9765±0.05%/day were recorded in LF1T1. Quadratic regression analysis of growth indices against microbial counts revealed that at concentration of 50.7CFU/ml the best weight gain of 0.39g was obtained. The treatment LF1T1 also produced the highest protein efficiency ratio (PER) (0.007±0.0003) and nitrogen metabolism (NM) (4.86±0.23). Survival was significantly low (22.5±5.1%) in AT0 while the highest value (42.3±3.18%) was recorded in LF1T1. Amongst strain F4S8, LF2T1 had significantly higher (p<0.05) MWG (0.4197±0.01g). The optimum treatment concentration was 62.5CFU/ml at 0.33g MWG. The treatment LF2T1 also had the best PER of 0.007±0.000 while T0 recorded the least value (0.003±0.0004). The highest survival (44.2±1.5%) was recorded in LF2T2. The studied L. fermentum strains was viable in the feed which successfully improved the performance and nutrient utilization in C. gariepinus larvae. Thus, it’s application in fish feed production is recommended.
Keywords: Lactobacillus fermentum, growth, C. gariepinus, fry, larvae.
