ABSTRACT

A 56-day feeding trial involving 120 day-old Sayed broiler chicks was conducted to evaluate the growth performance, carcass characteristics, haematological and serum biochemical profiles and economics of production of broilers fed graded levels of processed cocoyam (Colocasia esculenta) meal (PCM) as a replacement for maize. The birds were randomly assigned to four dietary treatment groups of 30 birds per treatment and 10 birds per replicate in a Completely Randomized Design (CRD). The birds were fed diets containing graded levels of processed cocoyam meal to replace maize at 0, 5, 10 and 15% designated as T1, T2, T3, and T4 respectively. The processing of the cocoyam involved soaking in water for 9 days and sun drying for 3 days. The birds were weighed at the beginning of the experiment and weekly thereafter while mortalities were recorded as they occurred. Feed and water were offered ad-libitum. At 8 weeks of age, two birds per replicate were weighed and slaughtered for carcass evaluation, while blood was collected from the wing vein of two birds per replicate and 6 birds per treatment for haematological and serum biochemical determination. The results of the experiment showed that processed cocoyam meal contains crude protein of 4.03% and crude fibre of 8.32%. Antinutritional contents of Colocasia esculenta were tannin (g/100 gDM) (Condensed and hydrolysable), phytate, oxalate, saponin and hydrocyanide (mg/kg) at 0.20, 0.03, 0.28, 0.41, 0.21 and 7.55 respectively. Final live weight, total weight gain (TWG), average daily gain (ADG) and feed conversion ratio (FCR) differed (P<0.05) significantly among treatment groups. The final live weight, TWG and ADG of the birds fed the control diet, and diet 2 were significantly (P><0.05) higher than the final live weight of birds fed the other diets. However they are similar (P> 0.05) to the final live weight of birds fed diet 3 (1966.44g). Birds fed diet 4 had significantly (P<0.05) lower TWG and ADG of 1755.55g and 31.35g, respectively than the other diets. Birds fed control diet and diet 2 had significantly (P><0.05) lower FCR values of 2.37 and 2.54 respectively than birds fed diet 3 (2.72) and diet 4 (2.82). Significant differences (P><0.05) were observed in live weight at slaughter, defeathered weight, dressed weight, dressing percentage and eviscerated weight, neck, back and wing. Birds fed the control diet (1 .94kg) had significantly (P><0.05) higher live weight at slaughter than other diets but similar (P>0.05) to the weight of birds fed diet 2 (1.88kg). There were no significant differences (P>0.05) in organ weight except for liver, spleen and abdominal fat. In serum biochemistry, it was observed that globulin, creatinine and glucose remained statistically unaffected (P>0.05) while albumin, urea, cholesterol and total protein values were significantly different (P<0.05) among treatment means. The glucose levels ranged from 35.00 to 1 14.67mg/di. Birds fed the control diet had significantly (P><0.05) higher blood urea level of 46.35mg/di than the birds fed diets 2, 3 and 4. Results of economics of production show that the birds fed processed cocoyam meal (PCM) with 5% inclusion level had the best profit margin (N676.00) apart from birds fed the control diet. It would be concluded that processed cocoyam meal (PCM) could be incorporated up to 5% as a replacement for maize in broiler diets with no deleterious effect on their performance.