Assessment of Duckweed Supplement Diet to Fishmeal on the Growth Performance of Oreochromis niloticus Fingerlings

Abstract

Oreochromis niloticus is the most cultured fish in tropical freshwater aquaculture systems and second most cultured fish after carps in the world. In Kenya, Oreochromis niloticus has potential in eradicating hunger and poverty but this is limited because of its low yield attributed to unavailability of quality, reliable and affordable farm-made feeds, and a problem that needs to be addressed. Initiatives geared towards improving Oreochromis niloticus production but main challenges still remain to be cost implication in the production of feeds. This study aims at addressing feed costs challenges by the use of an alternative locally available feeds to replace the expensive commercially produced feeds. The study was to study was conducted at Dominion farm situated in Siaya County along the shores of Lake Victoria in Western Kenya. The main objective was to assess the effects of locally available duckweed diet on growth performance of O. niloticus fingerlings. 450 experimental sexed reversed male fingerlings of mean weight 3.1±0.10 and length of17.44±0.42 mm were randomly distributed in three concrete circular tanks of 500 litres capacity each with two replicates. In each tank, 50 fingerlings were stocked and fed with a food ration of 5% body weight for 72 days. The fingerlings were fed in the morning at 9.00 A.M. and evening 4.00 PM daily using a dry duckweed meal, fishmeal and control diet. Sampling was done biweekly where length and weight gain of the fingerlings were obtained using a measuring board and weighing scale respectively. Average weight at the end of the experiment for duckweed, 50% dry duckweed diet-50% fishmeal diet and control were 56.03±1.15 59.54±0.31, 66.73±1.79, respectively. The dry duckweed diet influence on the growth parameters was less than fishmeal diets. However, at the ratio of 1:1 duckweed to fishmeal diet, the weight gain was significant. There was a significant difference in FCR, PER, AWG, and SR (p<0.05) when fingerlings were fed with three diets. Oreochromis niloticus showed an increase in growth performance during the entire period. This result indicates that dry duckweed can be used to minimize the high cost of fishmeal without negatively affecting fish growth.