Brazilian propolis extract used as an additive to decrease methane emissions from the rumen microbial population in vitro.

Propolis is a product that is rich in phenolic compounds and can be utilized in animal nutrition as a dietary additive. In this study, the effects of a Brazilian green propolis extract on rumen fermentation and gas production were determined. The fate of propolis phenolic compounds in the rumen medium was also investigated. Fermentation was done in 24-h batches over three periods. Inoculates were obtained from cows fed on grassland hay and concentrate. Propolis extract in a hydroalcoholic solution was applied at increasing doses to the substrate (1 to 56 g/kg). The fermentation substrate consisted on a mixture of alfalfa hay, soybean meal, and wheat grain mixture in dry matter. After 24 h of fermentation, seven new compounds were observed in the medium in amounts that correlated to the propolis dose. The dose of propolis extract linearly decreased the pH of the medium and linearly increased propionate production, which reduced the acetate-to-propionate ratio and influenced the total production of short-chain fatty acids. Propolis also linearly reduced methane production and increased the carbon dioxide-to-methane ratio. Ammonia nitrogen levels and in vitro digestibility of organic matter were similar among the treatments. The combination of increased propionate production and decreased methane production suggests better energy utilization from the feed.

Nitrogen metabolism, digestive parameters, and protein requirements for the maintenance of buffalo growth.

The objectives of this study were to evaluate the effect of crude protein (CP) levels in the diet of growing female buffaloes on nitrogen metabolism and estimate protein requirements for maintenance. Four female buffaloes were used, cannulated in the rumen, with an average initial body weight (BW) of 355 ± 3.5 kg, in a Latin square (4 × 4) with four animals and four levels of CP in the diet (70, 90, 110, and 130 g/kg dry matter (DM)) composed of corn silage and concentrate. The increase in protein intake with increasing levels of dietary CP resulted in a higher concentration of ammonia in the rumen and higher ruminal disappearance of PB. However, omasal flow of protein increased linearly as did the efficiency of microbial protein synthesis. The CP levels affected DM intake and other nutrients positively, but there was no effect on nutrient total digestibility. Nitrogen (N) balance, when expressed relative to N intake, had an average value of 48.5 % observed across. The protein requirement for the maintenance of growing female buffaloes was 4.6 g CP/kg BW(0.75).