Effects of Earthworm-Formulated and Commercial Feeds on the Growth and Development of Nile Tilapia (Oreochromis niloticus)

Abstract

Cultivation of fishes like Oreochromis niloticus is extensive throughout the world, leading to an ongoing endeavor to improve feed production by formulating cheaper and nutritionally comparable feeds. This study aims to compare the effect(s) of the earthworm-formulated feeds and commercial feeds in terms of growth and development of O. niloticus fingerlings. Two set-ups of glass aquaria, each containing 20 O. niloticus (approximately 3 months old) fishes, were prepared. One was exclusively fed with earthworm-formulated feeds while the other set-up with commercial feeds. The weight, total length, fork length, caudal length and body depth were measured every week for 8 weeks and the mean values were compared between the two set-ups. The survival and general/feeding behavior of the fishes were also observed up to 8 weeks time. Statistical analysis showed no significant differences in all morphometric variables between the fishes fed with earthworm-formulated feeds and the fishes fed with commercial feeds during 8 weeks. A higher survival rate was observed in the earthworm-formulated set-up. As to the feeding behavior, approaching, consuming and stalking of feeds were observed in the fishes fed with earthworm- formulated feeds and commercial feeds; the fishes in the commercially-fed set-up showed more aggression and loss of interest towards their feeds. On the contrary, the fishes fed with earthworm- formulated feeds showed less aggression and continuous interest towards their feeds. It can then be concluded that the earthworm-formulated feeds were comparable to the commercial feeds in terms of its effects on the growth and development of O. niloticus.