The effects of feeding graded levels of microbially fermented cassava tuber wastes (CTWs) on blood viscosity and bone quality of finisher cockerels.
Authors: Aro S. O. 
Published: February 2021

Two cassava tuber wastes (CTWs), namely cassava peels (CAP) and cassava starch residues (CSR) were subjected to solid substrate fermentation using a combination of microorganisms (Lactobacillus delbrueckii, Lactobacillus coryneformis and Aspergillus fumigatus), in order to improve their nutritive quality and reduce their levels of anti-nutrients. The microbially fermented products from the two wastes: microbially fermented cassava peels and microbially fermented cassava starch residues (MFCP and MFCSR) were thereafter used at varying levels to formulate seven standard cockerel diets designated as Diet 1 (0% CTWs), Diet 2 (20% MFCP), Diet 3 (40% MFCP), Diet 4 (60% MFCP), Diet 5 (20% MFCSR), Diet 6 (40% MFCSR) and Diet 7 (60% MFCSR). Two hundred and ten day-old cockerel chicks were randomly allotted to the seven treatment diets. The chicks were fed with these diets for seventeen weeks. Forty two birds were selected at the end of the seventeenth week of the experiment and were slaughtered. Bone quality and blood viscosity of the cockerel birds were used as response criteria. The result showed that the whole blood viscosity was statistically similar while plasma viscosity was influenced significantly (P<0.05) by the dietary treatments. Whole blood viscosity ranged from 2.36 centistokes in 60% MFCSR diet to 2.82 centistokes in the 20% MFCP diet. Blood viscosity decreased with increasing levels of CTWs in the diets. Flesh to bone ratio of the femur decreased correspondingly with dietary levels of the fermented wastes except in 40% MFCSR while percentage bone moisture increased as the level of inclusion of the wastes increased in the diets. 40% MFCPhad the highest percentage bone ash (33.83%) while 20% MFCSR had the highest value for volumetric bone density (1.15g/ml) while birds fed the 20% MFCP diet had the least value for bone ash percentage (27.12%) and bone ash concentration. Since bone ash concentration, percentage bone ash and weight of bone ash in all the treatments did not vary significantly in comparison with the control except in 20% MFCP, it could be concluded that the utilization of these wastes even at 60% level would not compromise the bone quality parameters of cockerel birds. This experiment also showed that cassava tuber wastes could decrease both plasma and whole blood viscosity and significantly so if plasma viscosity is taken into consideration. The lower viscosity of birds fed CTW with higher inclusion is suggestive of a positive influence of the CTW diets on the mechanical and geometric properties of the red blood cells. ><0.05) by the dietary treatments. Whole blood viscosity ranged from 2.36 centistokes in 60% MFCSR diet to 2.82 centistokes in the 20% MFCP diet. Blood viscosity decreased with increasing levels of CTWs in the diets. Flesh to bone ratio of the femur decreased correspondingly with dietary levels of the fermented wastes except in 40% MFCSR while percentage bone moisture increased as the level of inclusion of the wastes increased in the diets. 40% MFCPhad the highest percentage bone ash (33.83%) while 20% MFCSR had the highest value for volumetric bone density (1.15g/ml) while birds fed the 20% MFCP diet had the least value for bone ash percentage (27.12%) and bone ash concentration. Since bone ash concentration, percentage bone ash and weight of bone ash in all the treatments did not vary significantly in comparison with the control except in 20% MFCP, it could be concluded that the utilization of these wastes even at 60% level would not compromise the bone quality parameters of cockerel birds. This experiment also showed that cassava tuber wastes could decrease both plasma and whole blood viscosity and significantly so if plasma viscosity is taken into consideration. The lower viscosity of birds fed CTW with higher inclusion is suggestive of a positive influence of the CTW diets on the mechanical and geometric properties of the red blood cells.