EFFECTS OF DIFFERENT PROCESSING METHODS ON NUTRIENT COMPOSITION OF SWEET POTATO LEAF AS FEED FOR NILE TILAPIA, OREOCHROMIS NILOTICUS (LINNAEUS, 1758)

Abstract

The use of alternative feeds aims to increase productivity and reduce the feed costs in aquaculture production. The present study was conducted to evaluate the effects of different processing methods on nutrient composition of sweet potato leaf (SPL) and its effect on growth performance, feed utilization and body composition of O. niloticus. Fresh sweet potato leaves were collected and processed differently, namely air dried (AD); yeast fermented (YF); rumen fluid fermented (RF) and naturally fermented (NF). Following proximate analysis five isonitrogenous and isoenergetic feed: one control diet and four processed SPL based diets were formulated by replacing 30% CP of SBC with processed sweet potato leaf CP. A total of 300 Nile tilapia fingerlings each with an average body weight of 10.55±0.19g were stocked in 15 hapas installed in the concrete ponds in triplicate and fed with 5% of their body weight three times a day for three months. The results of proximate analysis of SPL showed the highest CP (33.9%), and lowest CF (7.80%) in YF and the highest fat (8.55%) and ash (12.14%) content were recorded in RF. AD SPL showed the highest DM (93.41%) and NFE (55.87%) content. The fish was survive 100% in all treatment except in fish feed with ADSPL based diet (96.6%). Fulton’s condition factor of experimental fish was greater than 1 in all treatment. SR and FCR was not affected by tested diets (P > 0.05). However, a significant difference in growth and feed utilization parameters were noticed. Fish fed with control diet showed better weight gain (61.85g), specific growth rate (1.66%/fish/day) and feed utilization efficiency than others except fish fed with yeast fermented sweet potato leaf. Therefore, it can be concluded that the yeast fermented sweet potato leaf meal can be used for O. niloticus feed without any adverse effects on growth performance, feed utilization and body composition.