Pirouz Shakeri1, Zoey Durmic2,3, Joy Vadhanabhuti2,3, Philip E Vercoe2,3. 1. Animal Sciences Research Section, Kerman Agricultural Research and Education Center, AREEO, Kerman, Iran. 2. School of Animal Biology, The University of Western Australia, M085, 35 Stirling Hwy, Crawley, WA, 6009, Australia. 3. Future Farm Industries Cooperative Research Centre, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia.
Abstract
BACKGROUND: The industrial processing of olive generates a high quantity of by-products. The objective of this study was to examine the effects of products derived from olive trees, i.e. leaves, fruits or kernels as a sole substrate (part A), and crude extract from leaves combined with a substrate (part B) on rumen microbial fermentation in an in vitro batch fermentation system. In this study, total gas production, methane production, and concentrations of volatile fatty acids (VFA) and ammonia in ruminal fluid were measured. RESULTS: In part A, in vitro fermentation of leaves or fruits yielded a gas and total VFA production that were comparable with control substrate, while most of them produced significantly less methane (up to 55.6%) when compared to control substrate. In part B, amongst leaf extracts, only addition of chloroform extract reduced methane production, which was also associated with a decrease (P < 0.01) in gas production. This effect was associated with a significant reduction (P < 0.01) in acetate to propionate ratio and ammonia production, but not in reduction in VFA concentrations. CONCLUSION: Olive leaf and olive leaf chloroform extract reduced ammonia production and increased the molar proportion of propionate in the rumen and can assist in developing novel feed additives for methane mitigation from the rumen.
BACKGROUND: The industrial processing of olive generates a high quantity of by-products. The objective of this study was to examine the effects of products derived from olive trees, i.e. leaves, fruits or kernels as a sole substrate (part A), and crude extract from leaves combined with a substrate (part B) on rumen microbial fermentation in an in vitro batch fermentation system. In this study, total gas production, methane production, and concentrations of volatile fatty acids (VFA) and ammonia in ruminal fluid were measured. RESULTS: In part A, in vitro fermentation of leaves or fruits yielded a gas and total VFA production that were comparable with control substrate, while most of them produced significantly less methane (up to 55.6%) when compared to control substrate. In part B, amongst leaf extracts, only addition of chloroform extract reduced methane production, which was also associated with a decrease (P < 0.01) in gas production. This effect was associated with a significant reduction (P < 0.01) in acetate to propionate ratio and ammonia production, but not in reduction in VFA concentrations. CONCLUSION:Olive leaf and olive leaf chloroform extract reduced ammonia production and increased the molar proportion of propionate in the rumen and can assist in developing novel feed additives for methane mitigation from the rumen.
Authors: Francesca Bennato; Camillo Martino; Marco Di Domenico; Andrea Ianni; Benli Chai; Lisa Di Marcantonio; Cesare Cammà; Giuseppe Martino Journal: Vet Sci Date: 2022-08-24