The effect of using solid-state fermented peeled and unpeeled cassava root tubers and limiting amino acid supplementation on metabolisable energy for meat-type cockerels

A preliminary in-vitro solid-state fermentation of peeled (PCRM) and unpeeled cassava root tuber meal (UCRM) using Aspergillus niger van Tieghem, was conducted, followed by a force-feeding experiment to investigate the effects of a diet of solid state fermented peeled (PCRM) and unpeeled (UPCRM) cassava root, supplemented with limiting amino acid, on metabolizable energy (ME) for meat-type cockerels. Forty eight, 84 d-old meat-type cockerels (Ross 308) were assigned to 8 treatments consisting of 6 birds per treatment laid out in a 2 × 2 × 2 factorial arrangement of treatment consisting of PCRM and UCRM subjected or not to solid-state fermentation and supplemented with or without limiting amino acids. An additional 6 cockerels were used for endogenous study. Peeling of cassava root increased (P < 0.05) gross energy content of the resultant cassava meal when compared with UCRM. Solid-state fermentation using Aspergillus niger increased (P < 0.05) the crude ash, ether extract and arginine concentration of PCRM and UCRM. Solid-state fermented PCRM recorded the highest (P < 0.05) amylopectin, least (P < 0.05) resistant starch and hydrocyanide concentration. Highest (P < 0.05) apparent metabolizable energy (AME) and nitrogen corrected AME (AMEn) values were obtained for cockerels fed with solid-state fermented PCRM supplemented with or without amino acid. However, supplementation of solid-state fermented PCRM with amino acid resulted in highest (P < 0.05) true metabolisable energy (TME) and nitrogen corrected TME (TMEn) for meat-type cockerels. Reduced (P < 0.05) AME and AMEn values were recorded for UCRM, regardless of solid-state fermentation and amino acid supplementation. In conclusion, solid-state fermentation and amino acid supplementation of PCRM resulted in improved AME, AMEn, TME and TMEn values for meat-type cockerels. Amino acid supplementation had no improvement on AME, AMEn and TME values of UCRM for meat-type cockerels