Effect Of Glycine Max, Rastrineobola Argentea And Caridina Nilotica Meals On Water Quality, Growth Performance And Survival Of Oreochromis Niloticus Fry

ABSTRACT

Nile tilapia (Oreochromis niloticus), one of the main stay of Lake Victoria fisheries, was introduced in the 1950s and 1960s to boost capture fisheries. However, its production has declined dramatically over the years due to over exploitation and its consumption preference by the ever increasing Kenyan population. The decline of capture fisheries has made aquaculture production be considered as the future solution to the declining of capture fisheries and the availability of fish globally. Production of O. niloticus is still low in developing countries because of inadequate quality fingerlings and unavailability of good quality fish feeds due to high cost and scarcity of fishmeal raw materials. Hence, an eight-week experimental study was undertaken to determine the effect of soya bean meal (SBM) with reference to common fish feed ingredients like, Rastrineobola argentea meal (RAM), Freshwater shrimp (Caridina nilotica) meal (CNM) and commercial fish meal (CFM, control diet on water quality, growth performance and survival of O. nilotica fry. The study was done at the National Aquaculture Research Development and Training Centre (NARDTC) in Sagana, Kirinyaga County. Each tank was randomly stocked with 50 fry (mean wt. of 0.4 ± 0.01g) in triplicate glass aquaria tanks measuring 67.5 cm by 34.4 cm by 32.0 cm and fed on diets comprising RAM, SBM, CNM or CFM. Feeding was performed manually at 3% wet body weights twice daily in equal rations at 10. 00 hrs. and 16.00 hrs. except during the sampling days. Essential water quality parameters [temperature, dissolved oxygen (DO) and pH] were monitored daily at 9.00 hrs. and 15.00 hrs. The fry was randomly sampled for determination of specific growth rate (SGR) and feed conversion ratio (FCR) on a weekly basis between 7.30 hrs. to 9.00 hrs. Survival was determined on daily basis for eight weeks. Using Graph Pad prism software, data were analyzed using one-way analysis of variance to compare SBM and each of the three diets. Data revealed that there was no significant difference in water quality parameters between the experimental groups (p > 0.05) and the parameters were within the acceptable range, temperature (25-30⁰C), dissolved Oxygen (>3mg/ˉL) and pH (6.5-9.0). The weights of fingerlings fed on SBM was higher than those fed on RAM or CNM (p> 0.05). However, those fed on CFM was considerably higher than those fed on SBM, but not significantly different. Specific growth was not significantly different (p>0.05). The percent SGR in weight per day of fry fed on SBM was considerably higher than those fed on either RAM or CNM (p> 0.05). The differences in the FCR of fry fed on the three experimental diets were statistically significant (p< 0.05). The length gains over the 8-week study period of fry fed on SBM was considerably higher than those fed on RAM or CNM (p< 0.05) but not CFM. The percent SGR in length per day of fry fed on SBM was considerably higher than those fed on either RAM or CNM, but not CFM (p < 0.05). The survival of fry fed on SBM was significantly higher than those fed on RAM and CNM (p< 0.05). The SBM is not only considerably better than RAM and CNM but is also comparable to CFM in terms of its effects on water quality, growth performance and survival of O. niloticus fry. The result gave a distinctive evidence on the viability and sustainability of using soya bean meal as a complete diet for fry to fry in regard to fish farming. Therefore, from the study results, it is possible to completely replace fish meal with SBM in the diet of ON in aquaculture. Farmers could adopt the use of BM as replacement for expensive commercial feeds and very competitive fish ingredients like R. argentea or C. nilotica- in raising O. niloticus fry to fry. Further research is necessary to evaluate the full potential of SBM on grow-out O. niloticus.