EVALUATION OF DETOXIFIED JACK BEAN (Canavalia ensiformis (L.) (DC.) IN BROILER STARTER RATIONS WITH AMINO ACID SUPPLEMENTS

Abstract

An experiment was conducted with broiler chicks allotted to seven dietary treatments, to examine the effectiveness of extraction procedures, autoclaving and dietary supplements of amino acids on the nutritive value of jack beans. Extraction of jack beans with aqueous NaHC03 solution (8.4 gll) at temperatures maintained between 80 - 90 OC for 48 h, followed by autoclaving for 30 minutes at 121 OC, reduced nutrient contents and canavanine, a toxic amino acid, to significantly lower levels than in similarly but water extracted jack beans Inclusion of the extracted and autoclaved beans at levels of up to 300 glkg in broiler starter diets supplemented with methionine, lysine and methionine + lysine, gave faster growth rate and enhanced feed consumption than the control diet. The efficiency of feed conversion, efficiency of feed utilisation and protein efficiency ratio were statistically similar for all dietary treatments. Lysine supplementation improved the performance characteristics of chicks on the NaHC03-extracted diets while methionine enhanced the performance of birds on the water-extracted autoclaved jack bean (AJB) diets. Amino acid supplements were however ineffective against nutrient retention and utilisation probably due to complex interactions and antagonism between amino acids and their analogues. The use of other amino acids besides lysine for supplementing extracted AJB diets and a careful study of extraction procedures were recommended before the beneficial effects of detoxification can be realised.