REDUCING FEED COST BY USING SUB-GRADED SWEET POTATO TUBER AS A NON-TRADITIONAL ENERGY SOURCE IN NILE TILAPIA, Oreochromis niloticus DIETS
Medhat E. Seden1*; Nader E. El-Tawil1; Talaat N. Amer1;
Mohammad. H. Ahmad1 and Tharwat I. Dawood2
1Department of Fish Nutrition, 2Department of Fish Economic, Central Laboratory for Aquaculture Research, CLAR, Agriculture Research Center, Egypt.
*Corresponding author’s e-mail: [email protected].
|Received 16/ 4/ 2017||
Accepted 28/ 5/ 2017
This study was conducted to assess the nutritional and economical value of using sub-graded sweet potato, Ipomea batatas L. tuber (SPT) as a non-traditional source of energy instead of yellow corn (YC) in practical diets of Nile tilapia (3.1±0.04 g). Five isonitrogenous and isolipidic diets (30% crude protein and 8.4 % crude lipid) were formulated to contain different levels of SPT replaced 0.0 (control), 25, 50, 75 or 100% of yellow corn meal. Each diet was fed in triplicate groups two times a day for 12 weeks to apparent satiation. Results demonstrated that, SPT had good potential as a level 100% substitute of the energy supplied by YC for Nile tilapia. No significant differences were observed (P>0.05) in growth performance, feed conversion ratio and protein utilization values compared to fish fed on control diet. Also, results indicated that fish proximate
chemical analysis was not significantly affected by partial or total replacement of SPT for YC in fish diet. Moreover, the economic evaluation showed that diet containing 100% SPT reduced the feed cost by 13.78% compared to fish fed on control diet. These results suggest that sweet potato tuber could substitute up to 100% of yellow corn meal as an energy source in Nile tilapia diet without adverse effects on growth performance and with an irresistible increase in profit margin by reducing the feed cost.
Keywords: Sweet potato tuber, Nile tilapia, growth performance, feed utilization, economic evaluation.