Fermented bambaranut waste meal and palm kernel cake affect nutrient utilization, growth, and gut morphology of Clarias gariepinus

Abstract

There is need to reduce cost of feed production using agro-waste ingredients. Bambaranut waste meal (BNWM) and Palm kernel cake (PKC) were valorized by solid-state fermentation for 7 days. Five (5) isonitrogenous (39.44% CP) and isoenergetic (2,731 kcal/kg) feeds were produced to vary in their inclusion of fermented FPKC: FBNM as followed: Feed 1, 0:400, Feed 2: 100:300, Feed 3: 200:200, Feed 4: 300:100 and Feed 5: 400:0. Fingerlings of C. gariepinus of average weight 0.176g were stocked at 15 fish per three replicate plastic aquaria per treatment feed. The catfish were fed the treatment feed ad libitum for 70 days. Fish fed Feed 2 (FPKC: FBNM, 100:300) had the best specific growth rate (SGR) of 4.04±0.05 % day-1. The fish SGR reduced with increasing inclusion of FPKC. A better SGR was recorded for catfish-fed diets with BNWM and PKC combined than diets made solely of either of the ingredients. Food conversion ratio was lowest for Feed 2 (0.80±0.02), followed by those fed Feed 1 (1.21±0.05) and then those treated with Feed 4 (1.21±0.03). Protein efficiency and conversion ratios were best for catfish treated with Feed 2. Also, catfish fed Feed 2 had the highest stomach weight, 1.62±0.09g, gut length, 16.51±0.01cm and gut weight, 2.29±0.02g. The highest contents of lysine (40.34±0.06 %) and methionine (27.30±0.01%) were recorded in Feeds 1 and Feed 2 (39.00±0.11%) and (27.02±0.08%) respectively. The high level amino acid in these feeds corresponded to high fish performances recoded.