Growth performance of Nile tilapia (Oreochromis Niloticus) fry fed on three different feeds

Abstract

In East Africa, feeds constitute 70% of the total fish production cost in aquaculture, making it, the most expensive of all the operational costs in aquaculture. This study examined the potential of using a local feed developed using the less competed and inexpensive alternative ingredients compared to fish meal. Three diets with varying nutrient compositions were tested on Nile tilapia fry (initial body mass ± SD: 0.2 ± 0.10 g). The experiment was set using three feeds (i.e., imported-1, Imported-2 and farm made) each tested in Triplicate groups of 50 fish per hapa (dimension: 6 m by 2 m by 1 m). The fingerings were fed five to eight times a day with their experimental feeds for six weeks using hands at 9:30 am, 10:30 am, 11:30 am, 12:30 pm, 2:00 pm, 3:00 pm, 4:00 pm, and 5:00 pm. The daily feeding ratio of each feed was measured at the beginning of every two weeks after sampling. The feeding response was monitored and mortality was recorded throughout the experiment. Dead fry (if any), were removed daily and the mortality was used to determine the number of live fries left in each hapa. The effect of different diets on specific growth rate (SGR%), survival rate (SR%) and water quality parameters was determined.The water was exchanged every day to avoid contamination with uneaten feed and waste. The water quality parameters that is, temperature, dissolved oxygen and pH were measured every day using a water quality meter throughout the experiment. Results indicated that water quality parameters such as temperature, dissolved oxygen and PH were within the acceptable range. The growth performance was best in the group fed on imported-1 feed, intermediate in those fed imported-2 feed, and lowest in the group fed on farm-made feed. Cost-benefit analysis results showed that maintaining fry on imported feed-1 and imported feed-2 is less profitable per kg of fingerlings sold than using on-farm feeds. However, when fingerlings are sold as pieces (i.e., as individual fish), the profit margin per fingerling sold is lowest in the group maintained on farm-made feed, intermediate in those fed on imported feed-2 and highest for the category fed imported feed -1.