In this study, the effect of adding propolis extract to sorghum grain varieties containing different levels of tannin on the in vitro gas parameters was investigated. The in vitro gas production, methane production, metabolic energy, net energy lactation and organic matter digestibility values were measured after 24, 48, 72, and 96 hours of incubation of the control group (without adding any additives to the sorghum varieties) and the group with 0.05% propolis extract in ethanol added to the sorghum varieties. The in vitro gas values formed at 24 hours in the Es8z102, Albanus, Sugar Drip, Gül Şeker, and Csr9303 sorghum varieties were found to be 164.5, 164.5, 158.6, 130.9, and 172.3, respectively. These values were determined to be 200.2, 201.4, 194.8, 176.6, and 198.4, respectively, with the addition of propolis. The highest in vitro gas production was found in the Csr9303 variety, which had the lowest tannin content. The in vitro methane values formed at 24 hours in the Es8z102, Albanus, Sugar Drip, Gül Şeker, and Csr9303 groups were found to be 26.12, 48.08, 32.47, 23.50 and 47.82, respectively. These values were found to be 26.69, 35.13, 30.39, 7.29, and 5.50, respectively, with the addition of propolis. With the addition of propolis, the gas production increased and the methane production decreased in variety Csr9303. The highest methane production was found in the Albanus variety. With the addition of propolis, methane production in the Albanus variety decreased, and it exhibited the highest gas production among the groups. Sorghum varieties with high tannin content had lower gas and methane production. With the addition of propolis, the amount of gas production increased and the amount of methane production decreased in groups with high tannin content. The addition of propolis extract to feeds containing 20 g kg-1 of tannin appears to have a positive effect on rumen digestibility and methane production.

28.2.2023