FEEDING VALUE OF PROCESSED HORSE EYE BEAN (MUCUNA URENS) MEAL AS ALTERNATIVE PROTEIN SOURCE IN PULLET CHICKS’ DIETS

The study was designed to evaluate the performance of pullet chicks fed graded levels of processed horse eye bean meal (HEBM) as partial replacement for soybean meal. The cracked beans were subjected to three processing methods viz: soaking in plain water for 48 hours, cooking for 90 minutes, and toasting on open fire at 100C after sundrying for seven (7) days. The processed beans were milled to pass through a four(4) mm mesh and used for diet formulation. Six experimental diets were formulated each at brooding and rearing phases, with diet 1 as control, while soybean meal in the control diets were replaced with the horse eye bean meal (HEBM) at 15, 30, 45, 60 and 75% in diets 2, 3, 4, 5, and 6, respectively. Three hundred and sixty (360) one day-old Lohman black pullet chicks were used at brooding phase, while two hundred and seventy (270), 56 days old chicks were used during the rearing phase of the experiment. Chicks were divided into six (6) groups on weight equalization bases and groups randomly placed on one of the six diets. The feeding trials lasted for eight weeks at brooding stage and twelve weeks during rearing period. Data generated were statistically analysed using analyses of variance procedures. The results revealed that level of HEBM in the diet did not significantly influence the average daily feed intake, average daily weight gain and feed conversion ratio. Cost of feed consumed and cost per kg weight gain were significantly reduced with the inclusion of HEBM in pullet chicks’ diets. It was concluded that 45 per cent of the soybean meal could be replaced by the HEBM in diets of pullets at the chick phase while HEBM can replace 60% of the soybean meal in the pullets’ diet at rearing phase.


INTRODUCTION
Intensive poultry production has been identified as one of the means of attaining animal protein sufficiency in the diet of the average Nigerian (Ani and Adiegwu 2005). Nigeria poultry industry is, however, facing tremendous setback and is on the verge of collapse arising from high cost of poultry feed, which accounts for 70-80% of the total cost of poultry production. The high cost of poultry feed has been traced to the increasing cost of maize, soybean and groundnut which are the main conventional sources of energy and protein, respectively (Effiong et al., 2013). A possible solution to the escalating cost of these ingredients is to explore the potentials of alternative feedstuffs as partial or total replacement for the expensive conventional feed ingredients.
The alternative vegetable protein being considered in this study is the horse eye bean (Mucuna urens) meal. Studies on the nutrient composition showed that the bean is a good source of protein (25-35%), carbohydrate (50-80%) and fat (8-11%). Effiong and Umoren, (2011) reported Glutamic acid, aspartic acid and leucine as the major amino acids in the horse eye bean. Umoren et al., (2007) had reported that raw horse eye bean did not support growth of broilers and rats. This, they attributed to the presence of some anti nutritional factors which were present in the raw and cooked beans. The anti-nutritional factors in the horse eye bean meal include trypsin inhibitor, lectins, phytates, phenols, cynogenic glycosides, tannins and L-3, 4 dihydroxyacetone (Effiong and Umoren, 2011). Effiong and Umoren (2011) had recommended a multi-processing technique (combined soaking and cooking for 48 hours and 90 minutes, respectively and toasting) as processing method in eliminating the anti nutritional factors in the horse eye bean. They noted that the adopted processing methods reduced the levels of phytates, tannins, phenols, HCN and oxalates by 49, 30, 87 and 63%, respectively.
The objective of this study was therefore to determine the optimum replacement level of the soybean meal by the processed horse eye bean meal (HEBM) in the diet of pullet chicks at brooding and rearing phases.

Processing of the horse eye bean
The horse eye bean was processed using methods that

Experimental diets
Six (6) diets each were formulated during brooding and growing phases to provide 20 per cent crude protein and approximately 2,800 kcal ME/kg of metabolizable energy and 15 per-cent crude protein and 2700 kcal ME/kg of metabolizable energy, respectively (Table 1). Diet 1 was the control, containing soybean meal as sole plant protein. Diets 2 to 6 contained the HEBM, replacing 15, 30, 45, 60 and 75 per cent of soybean meal (SBM), respectively in the diets. The diets were presented in the form of mash.

Experiment birds and design
A total of three hundred and sixty (360) one day-old, Lohman black pullet chicks were used for this study during brooding phase. The chicks were weighed and grouped according to their body weights into six (6) groups each of fifty (60) chicks. Within each group, they were further divided into three (3) replicates of twenty (20) birds each such that the overall mean weights and weight ranges were similar across the groups. Groups were randomly allocated to the six experimental diets in a completely randomized design. Each diet was fed as mash throughout the experimental period. Feed and water were provided ad libitum.
At growing phase, two hundred and seventy (270), 8 weeks -old pullets were selected, weighed and grouped according to their body weight into six (6) groups of forty-five (45) birds. Each group had three replicates of fifteen birds. Groups were randomly allocated to the six grower mash (test diets) in a completely randomized design. The experiment lasted for 56 days for the brooding phase and 12 weeks during the rearing/growing phase.

Data collection and analyses
Feed intake (pen basis) was measured daily; the weights of birds were taken weekly. Both the feed intake and weight gain were used to calculate the feed conversion ratio. Economics of feeding HEBM to growing pullets was evaluated.
Data generated from the experiment, were statistically analyzed, using the analyses of variance procedure. Significant means were separated by Duncan's new multiple range test (Duncan, 1955).

RESULTS AND DISCUSSION
Data for the performance of pullet chicks fed diet containing graded levels of processed horse eye bean meal are presented in Tables 2 and 3.  The results show that increasing dietary level of processed HEBM did not significantly (P> 0.05) influence the final body weight and the average daily weight gains of the chicks during brooding, but increased the weight gain significantly (P < 0.05) at growing phase. The results revealed that values were slightly depressed with increased level of HEBM in the diet at brooding phase, while at growing phase, the situation was reversed as birds on higher levels of HEBM performed better, except at 75% level of inclusion. This development shows the ability of the test sample to promote the birds' growth. The average daily weight gain recorded in this study was similar to the value 7.13g reported by Amaefule and Obioha (2005) for pullet chicks fed diets containing processed pigeon pea seed meal as replacement for soybean meal.
Dietary level of HEBM in the diet did not significantly (P>0.05) influence the average daily feed intake during brooding phase, but significantly influenced the intake of birds at growing phase. The result of this experiment was, however, lower than the values reported by Ani (2008) for pullet chicks fed processed velvet beans diet. Variation in the average daily feed intake during growing phase did not follow any pattern and therefore could not be attributable to any dietary effects.
Efficiency of feed utilization by the chicks was poorer with increasing dietary level of HEBM at brooding phase. This may be attributed to the inability of the birds to effectively utilize the diets, probably due to the presence of Non starch polysaccharides (NSP) in the diets (Nadeem et al., 2005;Balamurugan and Chandrascharan, 2010). The significant improvement in the FCR during growing phase could be due to the facts that birds at this stage may have developed adequate digestive enzymes to effectively handle the feeds. Generally, High FCR values observed at growing phase could be attributed to a shift of attention of the pullets from growth to the reproductive organs development.
Cost/Kg of feed slightly decreased with an increase in the dietary level of horse eye bean meal (HEBM). Values were statistically similar across the treatment groups. Birds fed control diet had significantly (P<0.05) higher cost of daily feed intake than birds on the experimental diets during brooding phase but were statistically similar during rearing phase. Birds fed 15% and 30% HEBM diets had the least cost of feed consumption at brooding phase while birds on 75% HEBM diet recorded the least cost of feed consumption during rearing. The differences were significant (P<0.05) among treatment groups.
The cost/Kg weight gain was significantly different among the treatment groups. Chicks on treatment diets had the lowest cost/kg weight gain relative to the control group. Birds on 60% HEBM diet had the least cost/kg weight gain, followed by those fed 45% HEBM diet. The significant reduction in the cost of feed/kg weight gain of birds fed experimental diets during rearing phase maybe attributed to their outstanding growth.

CONCLUSION
The result of the feeding trial revealed up to 30% of the soybean meal (SBM) could be replaced by the processed horse eye bean meal (HEBM) at brooding phase while 60% of the SBM could be replaced by HEBM during rearing phase without any deleterious effects on the birds.