QUALITY OF NIGERIAN GROUNDNUT CAKE AND ITS REPLACEMENT VALUES FOR SOYABEAN MEAL IN BROILER CHICKEN DIETS

Abstract

The bias for soyabean meal (SBM) above other plant sources of protein has made it to be in more demand. The scarcity and exorbitant price of SBM necessitate considering other suitable plant protein sources. Groundnut cake (GNC), if properly harnessed, can substitute for SBM in broilers’ diets due to its comparable proximate compositions, local availability and price competitiveness with SBM. However, the incidence of aflatoxin B1 (AFB1) contamination of GNC is a concern. Hence, this study investigated the quality of Nigerian GNC and its replacement values for SBM in broiler chicken diets. The preliminary stage of this study documented the perceptions and awareness of agriculturists in two states of each geopolitical zone of Nigeria through the administration of questionnaires on the AFB1 contamination of Nigerian GNCfrom the selected states with consideration to seasonal variability. The experimental phase involved two different studies (with and without toxin binders). The first study, which assessed the effects of different inclusion levels of GNC (0, 25, 50, 75 and 100%) as replacement of SBM in broiler diets without toxin binders, was further divided into three experiments. ExperimentsI and II involved one hundred and fifty (150) Cobb 500-day-old broiler chicks.The chicks were randomly selected and allotted to the five dietary treatments containing different inclusion levels of GNC respectively with 3 replicates and 10 birds per replicate in a completely randomized design on the second week of arrival after one week of acclimatization. The experimental broiler starter diets were provided for three weeksad libitum. Experiment I was completed at the age of 4 weeks (3 weeks of feeding starter diets) when two (2) birds per replicate were randomly selected subjected to various assessments. Experimental II continued with the remaining eight (8) birds per replicate and fed broiler finisher diets without toxin binder from the beginning of the 5th week until the end of the 8th week. Experiment III involved random allocation of 120 birds fed the control diets from day old until the end of the 4th week of age on the experimental finisher diets in three replicates with eight birds per replicate. The second study involvedone hundred and eighty-nine (189) broiler chicks fed diet containing 25% GNC as replacement of SBM from day old until the end of the 4th week. The birds were randomly distributed on seven (7) experimental diets at the beginning of the 5th week and lasted four weeks on the diets. Diets 1 and 2 contained 25 and 50% GNC as replacement of SBM respectively without toxin binders. The remaining five (5) diets contained 50% GNC as replacement of SBM with inclusions of different brands of toxin binders. Results revealed that inclusion of GNC above 25% as replacement of SBMin the starter and finisher diets significantly (P<0.05) depressed body weight gain and feed intake among the chicks in the first 4weeks of life as well as among those were fed both starter and finisher diets. However, inclusion of GNC up to 50% as replacement of SBM in the finisher diets of birds that received only the experimental finisher diets significantly (P<0.05) led to higher weight gain and feed intake as well as the more improved feed conversion ratio. Significant (P<0.05) reductions were also observed when the inclusions of GNC were increased to 75 and 100% as replacement of SBMin the diets of broilers fed starter diets only while the groups that were fed only finisher diets and starter and finisher diets did not show a significant (P>0.05) difference in the weight of the organs.The broilers fed diets containing toxin binder had significantly (P<0.05) higher weight gain, feed intake and better feed conversion ratio without any significant (P>0.05) difference on the haematological, serum biochemical and meat qualities of the birds. Hence, broiler productivity could be enhanced without any deleterious effects to the well beings of the birds and consumers by replacing 25% of SBM with GNC at the starter phase and 50% with toxin binder at the finisher phase of broiler chickens