Mass Culture of Daphnia magna Straus, 1820 in Fermented Medium as Feed to Enhance Nutrient Quality and Growth Performance of Nile Tilapia Oreochromis niloticus (Linnaeus, 1758) Larvae

Water flea (Daphnia magna Straus, 1820) is the best natural feed for tilapia larvae rearing, however, the quality of its nutrients and production is very dependent on the culture medium. The purpose of this study was to enhance the production and nutritional quality of tilapia fed with D. magna grown in medium that was fermented at different time intervals. This study was conducted using a completely randomised experimental design with five treatments and three replicates. Daphnia magna was mass-cultured using chicken manure as a culture medium fermented with probiotic microorganisms Lactobacillus casei and Saccharomyces cerevisiae for 7, 14, 21, and 28 days whereas the control was used on 0 days. Tilapia larvae fed four times daily with D. magna cultured in fermentation medium for 28 days produced the best final weight (2.52 g), relative growth rate (19.98 %), biomass weight (2.72 g), survival rate (98.55 %), net protein utilisation (1.90 %) and protein efficiency ratio of (2.95 %). The best tilapia's nutritional quality was also seen in the same treatment that was fermented for 28 days and gave the highest value for fatty acid profile of 9.36 % linoleic acid, and amino acid profile was in lysine of 32.19 ppm. The study showed that provision of D. magna feed mass-cultured using 200 g·L-1 of chicken manure fermented for 28 days gave the best results for growth of Oreochromis niloticus (Linnaeus, 1758) larvae.