Effects of phenolic compounds in propolis on digestive and ruminal parameters in dairy cows

Abstract

Four rumen-cannulated primiparous lactating cows were studied in a 4 × 4 Latin square design experiment to evaluate the effects of propolis-based products (PBP) with different concentrations of propolis and alcohol levels on total digestibility, (TD), ruminal digestibility (RD), intestinal digestibility (ID), pH, ruminal ammonia-nitrogen production (NH3-N), rumen microbial synthesis, and blood parameters. The feed consisted of 591.9 g/kg corn silage and 408.1 g/kg concentrate (dry matter [DM] basis), and treatments differed with regard to the inclusion (via ruminal cannula) or exclusion of PBP as follows: control (without the PBP), PBP B1 (3.81 mg of phenolic compounds/kg of ingested DM), PBP C1 (3.27 mg of phenolic compounds/kg of ingested DM), and PBP C3 (1.93 mg of phenolic compounds/kg of ingested DM). Inclusion of PBP reduced the RD of dietary crude protein (CP). Treatment PBP C1 reduced ruminal NH3-N production, while PBP B1 increased the ID of CP relative to that in the control. These findings indicate that propolis had a positive effect on rumen nitrogen metabolism. Rumen pH, efficiency of microbial protein synthesis, and blood parameters were not affected by addition of PBP, but there were significant effects on the other parameters when the treatments containing propolis were contrasted. Higher TD of DM (0.717 vs. 0.685), OM (0.737 vs. 0.703), and CP (0.760 vs. 0.739), as well as higher NDF (0.622 vs. 0.558) and TDN (0.747 vs. 0.712) were observed when comparing PBP C1 with C3. Inclusion of propolis in diets for dairy cows have positive effects on protein metabolism in the rumen. Variation in the amounts of phenolic compounds in the different PBP may explain the diverse effects on the digestive parameters evaluated.

Keywords

• additive
• ammonia nitrogen
• flavonoids
• phenolic acids
• ruminants