Nutritional evaluation of tigernut (Cyperus esculentus) meal as a replacement for maize in broiler diets

Abstract

A total of three hundred (300) day old unsexed “Fidan' broiler chicks averagely weighing 100.25±0.44g were used to study the response of broiler birds to diets containing different levels of yellow tigernut meal (TNM) as a replacement for maize. The birds were randomly allotted to five dietary treatments of three replicates each containing 60 and 20 birds respectively. After 28 days, the birds were again randomized based on weights to commence the finisher phase in a completely randomized design. The treatment diets consisted of 0%, 25%, 50% 75% and 100% of TNM as replacement for maize as diets 1 (control) 2, 3, 4 and 5 respectively. The result showed TNM to be low in protein (5.04%), moderate in fibre (13.01%) and high in ether extract (27.46%). Among the antinutritional factors, alkaloids, phytate and tannin were relatively high; 2.63mg/kg, 1.44mg/100g and 1.01mg/100g, respectively. Average weight gain (AWG) and final live weight (FLW) were high for birds fed 25 TNM and significantly (p<0.05) higher than the birds on control at the starter phase. However, at the finisher phase, the values were similar except for birds on 100% TNM that showed significant (p<0.05) depression in AWG and FWG. Feed intake was significantly affected by TNM inclusion levels and tended to improve (p<0.05) significantly as the level of TNM increases in the diets at the starter phase. And at the finisher phase, there was no significant (p>0.05) differences in feed intake across the treatment diets. The feed conversion ratio and protein efficiency showed similar trend both in starter and finisher phases of broiler production, except that at the starter phase, there was poor feed utilization as the level of TNM exceeded 25%, while at the finisher phase, depression only set in at 100% TNM. Feed cost (₦/kg) increased as the level of TNM increased in the diets. Among the nutrient utilization only fibre and ether extract were significantly (p<0.05) affected and this occurred only at 100% TNM. The TNM inclusion had no significant effect on the dressing percentage. Of all the carcass parameters measured only gizzard, caeca and abdominal fat showed significant differences, which all tended to increase (p<0.05) significantly as the level of TNM increases in the diets. It was concluded that at starter phase TNM as replacement for maize should not exceed 25% and at finisher phase, it may not exceed 75% for optimal growth performance.