In vitro evaluation of plants vegetable waste: effects on rumen fermentation

In vitro evaluation of plants vegetable waste: effects on rumen fermentation D. Tedesco, J. Parisi and L. Garavaglia Department of Health, Animal Science and Food Safety, University of Milan, Via Celoria 10, 20133 Milano, Italy; doriana.tedesco@unimi.it The plants vegetable waste originating from the processing of food and phytopharmaceutical products, still contain valuable phytochemicals. These waste could be recovered as feed or feed additives in ruminant nutrition. In an anaerobic batch culture rumen system, the activities of 18 vegetable waste were evaluated on microbial growth, pH, ammonia-nitrogen (NH3-N), volatile fatty acid concentration (VFA) and methane production. Of the waste were tested the raw material and their extracts after water, ethanol and heptane extraction. The waste, raw and extracts, in two replicates, were added into the bottles at three different concentrations. Data on pH, concentration and proportion of VFA, NH3-N and total bacterial count (after logarithmic transformation), were statistically analysed using the PROC GLM of SAS. Considering the effect on energy metabolism, among the screened waste, mango peel, larch sawdust and thyme waste, for all the dosage tested, exhibited an increase in total VFA concentration, associated with a slightly increase in methane production. Considering the effect on rumen nitrogen metabolism mango peel and larch sawdust decreased the NH3-N concentration (P<0.05). Of the plant waste with a detrimental effect on rumen fermentation, olive fruit waste decreased the VFA concentration (P<0.05). In conclusion, mango peel exhibited positive effects on rumen activity followed by larch sawdust and thyme, and they can be utilised to improve the rumen environment and nutrient use efficiency. Furthermore, the following beneficial effects were highlighted: mitigation of the environmental impact of livestock by improving the efficiency of diets and by the complete and efficient use of plant waste.