Suitability of on-farm formulated feeds and pond characteristics for Nile tilapia production in semi-intensive culture in selected farms of Rift valley region, Kenya

Abstract

High costs and inaccessibility to quality fish feeds in Kenya, have contributed considerably to the aquaculture sector stagnation. Consequently, farmers have opted for cheaper, locally available ingredients to formulate feeds for Nile tilapia in semi-intensive culture systems. In spite of these innovations, farmers continue to incur losses, an indication that the quality of on-farm formulated fish feeds could be compromised. This study therefore investigated proximate composition of on-farm formulated Nile tilapia feeds, the methods of formulation, the cost of these feeds compared to that of commercial feeds. The work also investigated pond characteristics in Bomet, Kericho and Nakuru counties in the Rift valley Region of Kenya. In the study, eighteen farms using semi-intensive method of raising Nile tilapia, were selected from the three counties based on a set of criteria. Fish feeds were collected from the selected farms and prepared for proximate analysis by standard methods. A comparison of proximate composition of the on-farm formulations, the commercial feeds and the Standard for Kenyan Commercial fish feed was done. Feed Cost analyses was also done through pilot surveys, from which best buy technique was used to determine cost per protein. In addition, farm and feed management practices were investigated through use of questionnaires. The results revealed a significant difference (P< 0.05) between the sampled feeds’ moisture, crude protein and mineral contents with the legislated standard levels and commercial feeds commonly used in the counties. There was also a significant difference between the three counties in terms of crude protein in the feeds, with feeds from Nakuru being significantly different from those used in Bomet and Kericho counties. On-farm formulated feeds recorded lowest cost per unit of nutrient compared to commercial feeds sampled, and the feeds formulated using imported ingredients. Nakuru County recorded the highest cost per gram of feed .The cost regime in Nakuru therefore varied significantly with the observed fish feed cost structure used in Bomet and Kericho counties (P < 0.05). Pond water physico-chemical parameters did not vary significantly between the three counties apart from conductivity which was significantly higher in fish ponds in Nakuru County. The study concludes that by using on-farm formulated fish feeds, farmers are able to minimise costs of production. However, the majority of these feeds do not meet the quality standards and nutrient requirements recommended for raising Nile Tilapia.