Nutritive value of raw and processed colocasia (Colocasia esculenta) corm meal for poultry

Raw, unpeeled colocasia corm meal contained (dry matter basis) 90.7 g kg(-1) crude protein, 796 g kg(-1) nitrogen-free extracts, 1234 mg kg(-1) total oxalates and 8.66 MJ kg(-1) nitrogen-corrected apparent metabolizable energy, About a third of the oxalates were removed by peeling the outer skin of the corms, and when peeling was combined with boiling, oxalate contents were lowered to 272 mg kg(-1). The nitrogen-corrected apparent metabolizable energy content was unaffected by peeling, but improved to 12.34 MJ kg(-1) when peeling was followed by boiling. In Experiment 1, inclusion of 100 g kg(-1) raw, unpeeled colocasia corm meal and raw, peeled colocasia corm meal in starter diets lowered weight gains and feed intake, and increased feed/gain ratio and mortality in layer-type chicks. In Experiment 2, peeling of corms followed by boiling overcame these adverse effects on chick performance, Pancreatic enlargement and reduced energy metabolisability and toe ash contents in chicks fed diets containing raw colocasia corm meals were also overcome by processing. The results of Experiment 3 showed that when supplemented with additional calcium, up to 200 g kg(-1) peeled, processed colocasia corm meal could be incorporated in chick diets. The present data suggest that oxalate is a major factor contributing to the anti-palatability and anti-nutritive effects of raw colocasia corms.