Utilization of autoclaved and fermented sesame(Sesamum indicum L.)seed meal in diets for Til-aqua natural male tilapia

摘要

Current research emphasis has been on the reduction of feed cost by incorporating processed sesame seed meal in the diet of tilapia. Raw sesame（Sesamum indicum） seed was soaked and subjected to either autoclaving or fermentation, after which their oil contents were mechanically extracted. Graded levels of autoclaved（71.2,165,5 and 296.3 g/kg designated as diets 1, 2 and 3, respectively） and fermented（71.0,164.3 and 292,2 g/kg designated as diets 4, 5 and 6, respectively） sesame seed meal were included into fishmeal based diets for Til-aqua natural male tilapia（NMT） fry（initial weight,1.69 ± 0.02 g）, A diet without sesame seed meal served as the control. Diets were approximately iso-nitrogenous（35% crude protein）. Fish were fed 5 times their maintenance requirement, which was 3.2 x 5 x [fish weight（g）/1,000]0.8 daily for 56 days. Processing improved the nutritional profile of raw sesame seed meal in terms of its crude protein and antinutrient compositions. Growth performance of fish was similar（P> 0.05） in the control and dietary treatments. The group fed diet 3 exhibited significantly poorer feed conversion ratio（1.14）, protein efficiency ratio（2.77） and economic conversion ratio（US$1.38/kg） relative to the group that received diet 5. Apparent digestibility coefficients for protein, lipid and energy in diet 3 were similar（P > 0.05） to those in diet 6 but significantly lower（P < 0.05） than those of the control and other dietary groups. The sesame seed meals processed with different methods did not significantly affect crude protein, crude lipid and gross energy compositions in the fish carcass. The study demonstrated that71.2 g/kg of autoclaved and 164.3 g/kg of fermented sesame seed meal could be incorporated in the diet of Til-aqua NMT with cost benefit.