Raw and processed wild colocasia corm meal ( Colocasia esculenta (L.) Schott, var. esculenta) as an energy source for broilers

Abstract

An experiment of 8 weeks duration was conducted with broiler chickens to evaluate the effect of processing on the nutritive value of wild colocasia corm meal. Colocasia corms processed by three methods (dehydrated raw, boiled and soaked, boiled) were used in the preparation of corm meals and used to replace maize meal in the control diet at 100 g kg −1. One hundred and twenty-eight unsexed 1 day old broiler chickens were used and after a preliminary period of 10 days, the dietary treatments were randomly allocated among 16 groups of 8 birds. Body weight gain and feed consumption were measured weekly. Energy metabolisability and nitrogen retention were estimated during the last week of the experiment by an indicator method. A slaughter study was carried out at the termination of the experiment. Processed colocasia corm meal had gross energy 14.9–15.0 MJ kg −1 dry matter and was comparable with maize meal as an energy source. However, unprocessed colocasia, when compared with the control, reduced feed intake by 70%, growth by 83% and dressing percentage by 12%. Pancreatic hypertrophy (55%) was observed in the raw colocasia group. Raw colocasia seemed to contain growth inhibitors. Boiling removed all these limitations. The boiling and soaking treatment gave no additional advantage over boiling. The effect of colocasia on the utilisation of dietary energy and nitrogen was minimal, and either heat treatment had a significant effect on nitrogen retention ( P < 0.05). It is concluded that the feeding value of wild colocasia corms could be easily improved by boiling in water for 30–45 min and processed corm meal could be used to replace maize in broiler diets at levels up to 100 g kg −1 without any adverse effects.