Evaluation of different processing methods of velvet bean (Mucuna pruriens) for use as a feed ingredient for broilers

摘要

Velvet beans (Mucuna pruriens) (VB) are valuable in subsistence and sustainable agriculture but the very limited scientific literature indicates that they are toxic when fed to poultry in commercial-type rations. Our earlier work has indicated that incorporation of VB in broiler diets at low levels (10%) gave similar performance as the control diet. This study explored whether higher amounts of VB (20%) can be included in broiler diets if further processing is used. The first experiment focused on the impact of various VB processing methods on broilers grown through 42 d of age. The treatments were the control (corn-soybean based-diet) and five VB diets at 20% (1. raw and ground, 2. roasted whole and ground, 3. ground and roasted, 4. soaked 24 h, roasted and ground, and 5. soaked 24 h, heat dried and ground. Broiler body weights and feed intake were lower (P<0.001) for all the experimental diets that contained processed VB and little or no impact of VB processing no broiler performance was noted. Feed conversion rates were often not superior (P<0.001) for the control diet and except for the first week, no significant differences were observed for mortality. Pre-chill carcass weights differed among the treatments (P<0.001) and the weights with VB flour were 50.8-62.1% of those with control feed. Percentage carcass yield was not affected by treatment. The second experiment focused on the supplementation of diets containing roasted VB with methionine and/or lysine as possible mechanisms to alleviate the negative effects of the anti-nutritional factors. No impact of methionine and/or lysine supplementation was found in any of the variables. For all VB diets, including the unsupplemented, roasted VB treatment similar to a treatment in Experiment 1, broiler body weights and feed intake were higher than in the Experiment 1. Differences in the results between Experiment 1 and 2 may be related to different initial content of anti-nutritional factors in the VB flour or factors related to experimental design. Content of L-Dopa in all VB flour utilized in Experiment 1 was high. More studies are needed to determine the presence of possible secondary anti-nutritional factors, as well as to examine the amino acid content of the VB and to find other processing methods.