Effects of substituting fishmeal with immobilized urea periodate oxidized lignocellulosic materials (LCMS): Acha (<i>Digitaria exilis</i> (Staph) and rice (<i>Oryza sativa</i> l.) on the growth of Nile tilapia (<i>Oreochromis niloticus</i> L.)

Abstract

Growth trails were conducted with Oreochromis niloticus fingerlings (mean weight 0.88 + 0.02 g) to evaluate the suitability of incorporating immobilized urea periodate oxidized Lignocellulosic Materials (LCMs) namely, Acha (Digitaria exilis (Staph) and Rice (Oryza sativa (L.) straws for substituting fishmeal from the reference diet (crude protein, 32.6%) at 15, 30, 45 and 60% test materials inclusion levels. Ten fish were stocked in triplicate replication in circular plastic tanks of 20-litre capacity, consisting of nine treatments including the control. Fish were fed to satiation, twice daily at 0900 and 1500 hours for 56 days. Best growth and food utilization indices were recorded in 30% Digitaria exilis and 45% Oryza sativa incorporated at crude protein levels of 20.98 and 24.27% respectively. From the results, it is plausible that 18.01% and 12.11% crude protein could be saved by using the non protein nitrogen in treated Digitaria exilis and Oryza sativa straws. The results of this study are discussed in the light of developing economically cheap, but nutritionally rich fish diets for sustainable fisheries development.

Key words: Limmobilization, Urea, lignocellulosic, fishmeal.

Journal of Aquatic Sciences Vol.20(1) 2005: 27-32