ABSTRACT

 Simlies were carried out to investigate the chemical and nutritional value of African Yam Bean (AVB). The proximate composition, gross energy, mineral and anti-nutritional factors present in r;1W AYB and AYB subjected to boiling, toasting, cracking and boiling and toasting and delnillinn were carried out. Experiment 2 was conducted to determine the effect of processing on metabolisable energy and protein using 18, 8 weeks old broilers and using forced feeding method. Safe level of inclusion of raw AYB was determined with Experiment 3. Raw AYB was incorporated into the diets at 5, 10, 15 and 20% levels of dietary inclusion and 150 broiler chicken of were used. Experiment 4 was carried out to determine the bio -utilization of nutrients hy birds fed different processed AYB. 5% each of the variously processed AYB (boiled, toasted, toasted and dehulled, cracked and boiled) were incorporated in diets 2, 3, 4 and 5, respectively. Experiment 5 investigated the optimal dietary level of inclusion ofboilcd seeds (being superior to other processed meal as observed in Experiment 4). 150 broiler chickens were also used and boiled AYB were incorporated into diets at 10%, 15% and 20%.levels. The experiments were carried out in a completely randomized design. The result of preliminary studies (Experiment 1) revealed that processing techniques significantly (P < 0.05) reduced the percentage of crude protein and ether extract. The value of crude protein ranged from 19.91% - 22.73% with raw having the highest while that of ether extract ranged from 3.19% - 5.95. There was no significant (P ''0.05) difference in the value of gross energy for both raw and processed seeds. Toasted seed had lhe highest values of both macro nutrients Na, K, P (except Ca) and micro nutrients be, Cu, Mg, Mn. Raw AYB had highest values of anlinutrilional factors. These include Trypsin inhibitors. Saponins, Tannins, Hydrocyanic acid and phytic acid. Seeds subjected to moist heating (boiled, cracked and boiled) had lhe highest percentage reduction of anti-nutritional factors. In Experiment 2, boiled seeds had lhe highest values of true metabolisable energy corrected to nitrogen (2.95 Kcal/Kg) and true metabolisable protein (20.90%). In Experiment 3, growth performance was generally depressed with increased inclusion of raw AYB in lhe diets, for dressing percentage, diet 2 compared favourably with dicll but diet I only fell within the normal range while the cut- parts favoured diet 5 For organ weights there were no significant (P >0.05) differences in the values of spleen and kidneys among the treatment means while the control diet and birds fed 5% level of inclusion had significantly low values of liver (3.42% and 3.40% respectively). All values observed for haematological indices fell within the normal range reported for broiler chicken. Feeding raw AYB resulted in increase in alkaline phosphatase and urea with increase in quantity of AYB. The cost benefit favoured diet 1 with cost/kg weight of N217.43 as opposed to all others. In Experiment 4, there were no significant (P>0.05) uil'fereiv'cs among treatment means except for mean total and daily feed intake and mortality. lhe dressing percentage values fall within the normal range for ail treatments except diet 4. cutparts (PDW) favoured diet 4. The liver of control, diets 2 (5% boiled), 3 (5% toasted), and 4 (cracked and boiled) compared favourably. The values of total protein did not favour diet 5. Significantly higher levels of urea and creatinine were observed for diets 3, 4, 5 as opposed to diets 2 (boiled) and control diet. The haematological parameters measured fall within the normal range for broiler chickens. The cost benefit favoured diet 2 with £4224.48 cost/kg gain. In Experiment 5, growth performance of birds fed graded levels ofboilcd AYB favoured diet 2 with 2.49 feed conversion ratio as opposed to 2.83 (diet 1), 3.47 (diet 3), 4.81 (diet 4). The percentage dressed weight fell within the range established for broiler chicken except diet 4 (63.64%). The values of cut parts favoured 4'3 for thigh, T4 for chest, drumstick and backcut. For organ weights [lie values ol kidney and liver did not follow any specific pattern while th > i gizzard were significantly higher for diets 3 and 4 when commit Ues 01 sPlcen and haematological parameters, they all fell within the normal range for hnh- \ d'Ct F°' M(TIC for the test diets. For total protein, diets 1, 2 and 3 were cmr <• CI„C1lckcns cxccPl for creatinine, diets I and 2 only. For urea and alkaline phosphatase m i ? Slmilar while for statistically lower than the value for the lest diets. The economies r' , (,controI> dlc(s were forcosl/kg weight gain as opposed to others. In conclusion boilin ,dV°Ured dlel 2 wilh ^>81.38 method. The anti-nutritional factors were reduced to the barest mi & e'11Crgcd lhc best processing iic highest true metabolisable energy and protein. 5% diclm v’ w,lh boiling; it also had proved to be unsafe. Birds fed 5% boiled AYB meal neiTn/ ?? ° lnc,USIOn °r raw AYB pasted, cracked and boiled, and toasted and dehulled Boiled lh°Se 5% °f nwcssmg technique) could be added up to 10% level nf,tin ■ , B ( 1e bes( meal of the i icvci ot dietary inclusion.