Determining the effects of some plant leaves and harvest residues on feed value and methane production in ruminant

This study investigated the potential use of hazelnut, black cherry, fig tree leaves, tomato, pepper, and eggplant harvest residues as feed resources or feed additives. Molasses and ecomass were added to vegetable harvest residues. The nutrient composition, in vitro gas production, and methane production of the feeds were determined. The in vitro gas production technique (Hohenheim gas test) was used to determine the gas production of the feeds. The experiment was conducted according to a completely randomized design. Among vegetable residues, eggplant had the highest crude protein (CP) content, while additives increased CP and reduced condensed tannin levels in all residues (P<0.05). Regarding neutral detergent fiber (NDF), additives decreased values in eggplant and pepper residues, potentially enhancing the feed intake of the animals. Fig leaves demonstrated the highest CP and lowest lignin contents among tree leaves, with superior in vitro true digestibility (IVTD) and energy values. Hazelnut and black cherry leaves exhibited high tannin levels, limiting their suitability as roughage, but their potential to reduce methane production was noted. Methane production was lowest in tomato residues, while fig leaves demonstrated the highest energy and IVTD values (P<0.05). As a result, hazelnut leaves and tomato residues have a significant effect on reducing methane production. The findings suggest that vegetable residues, particularly eggplant and pepper and tree leaves like fig, can serve as secondary roughage sources in ruminant diets, offering sustainable alternatives for reducing methane emissions. Future studies should explore different additives and their effects on nutritional and environmental parameters.