Common beans as a protein source in broiler diets Effects of processing, enzymes and probiotics on anti-nutritive factors and broiler performance

Abstract

A major challenge to Kenyan Livestock industry today is the inability to produce high quality feeds cheaply. Most of the common sources of protein such as soybean meal, cottonseed cake and fishmeal used in Kenyan feed industry are imported. This makes the final products expensive. To reduce costs, most manufacturers resort to using inferior quality alternatives that result in inferior feeds and leads to slow growing animals. Experiments were conducted to evaluate common beans as an alternative that may solve the twin problems of inferior quality feeds and expensive ingredient imports. The first experiment was designed to evaluate the chemical composition of various common bean varieties grown locally and the effect of processing on the ant-nutritive factors (ANFs) they contain. The results showed that local beans are high in CP (18 - 23%) which varies with variety. They are also high in ANFs. Lectins activity varies from 4 HU/mg to 16 HU/mg while Trypsin Inhibitor (TI) ranges from 2.13 TIU/mg to 3.04 TIU/mg. The results also indicated that soaking red haricot beans for 24 hours followed by cooking in boiling water for thirty (30) minutes is effective in eliminating ANFs while solid state fermentation is partially effective. The second experiment evaluated the effects of multienzyme supplementation on red haricot bean ANFs and utilization by broilers. The results indicated that enzymes have no effect on ANFs in red haricot beans. These results also indicated that oven heating had little or no effect on ANFs in red haricot beans. The third experiment evaluated the effects of cooked red haricot beans, multienzyme or probiotic supplementation on broiler performance. Diets based on boiled beans supported a broiler performance similar to maize–SBM control. Enzymes and probiotics had no beneficial effect on diet utilization. A final experiment was conducted to determine the appropriate level of boiled red haricot beans in broiler starter rations. The results showed that red haricot beans boiled for 30 minutes can be included in broiler starter rations at the rate of 20% in the diet (50% replacement of soybean protein). These results show there is potential in utilizing locally grown common beans in broiler starter diets. Key words: anti-nutritive factors, broilers, enzymes, probiotics, red haricot beans