NUTRITIONAL VALUE OF DIFFERENTLY PROCESSED KENAF Hibiscus cannabinus SEED MEAL AND THEIR APPARENT NUTRIENT DIGESTIBILITY COEFFICIENTS FOR AFRICAN CATFISH Clarias gariepinus

Feed constitutes more than 60% of operational cost in fish farming. Increasing cost of conventional feedstuffs due to competition between livestock and human necessitates research into cheaper and readily available unconventional feedstuffs for profitable fish farming. Kenaf (Hibiscus cannabinus) Seed Meal (KSM) has been reported to be a nutrient-rich feedstuff for aquaculture. However, there is limited information on the nutritional value and nutrient digestibility of KSM in the diet of Clarias gariepinus.

The chemical components of differently processed KSM; Roasted (RoKSM), Soaked (SoKSM), Sprouted (SpKSM ) and Cooked (CoKSM), as well as Raw (RaKSM ) were determined using standard methods. A reference diet (RD) and five (5) experimental diets of 70% RD and 30% of each  of the raw and processed kenaf seed meal constituted the experimental diets used for the digestibility trial. Chromic oxide was incorporated in the reference diet at 0.5% as an external marker. Using a completely Randomised Experimental d esign, the experimental diets were administered to C. gariepinus (n=180, 8.19±0.17g) in triplicate.  Apparent Digestibility Coefficient (ADC) of  Crude protein, ether extract and gross energy of the meals were calculated for Clarias gariepinus.

 Relative to the RaKSM which had a crude protein of 21.17%, other processing method enhanced the crude protein in KSM. The ash content,  Na/K ratio and Ca/P ratio were highest significantly (p < .05) for

RoKSM .  While soaking was not effective in reducing the content of tannin, saponin and oxalate in KSM, other processing techniques significantly reduced (p < 0.05) the levels of these anti-nutritional factors. Methionine was the limiting amino acid in the RaKSM and other processed KSMs . However, the Amino Acid Score (AAS)

 of the processed KSMs were higher than RaKSM. The apparent crude protein, ether extract and gross energy digestibility coefficient of kenaf seed for C. gariepinus significantly increased (p < 0.05) when processed (Table 1) . It can therefore be concluded that kenaf seed meal stands the potential of being used as ingredient of protein source in  the feed of Clarias gariepinus feed.