Effect of feeding phenolic compounds from propolis extracts to dairy cows on milk production, milk fatty acid composition, and the antioxidant capacity of milk

Four ruminally cannulated primiparous lactating cows were used in a 4 × 4 Latin square design experiment to evaluate the effects of propolis-based products (PBP; obtained under different concentrations of propolis and levels of alcohol) on milk production, milk fatty acid (FA) composition, and the antioxidant capacity of milk. The total mixed ration consisted of 591.9 g/kg of corn silage and 408.1 g/kg of concentrate [dry matter (DM) basis], and treatments differed with regard to the inclusion or exclusion of PBP as follows: control (CON; excipient without phenolic compounds from the propolis extract), PBP1–PBP3 (3.81, 3.27 and 1.93 mg of phenolic compounds/kg of ingested DM, respectively). Adding propolis to the diets had no effects on DM intake, milk production, feed conversion efficiency, milk solid concentrations, or somatic cell score. Milk FA composition was changed by the addition of PBP. The content of cis9,trans11-18:2 (CLA isomer) was 50.8% higher in the PBP2 than in the CON (P < 0.001). The PBP3 increased monounsaturated FA (MUFA) and polyunsaturated FA (PUFA) contents and reduced (P = 0.029) the proportion of saturated FA (SFA). Further, the addition of PBP reduced (P < 0.001) the n6:n3 ratio in milk fat when compared with that in the CON. The antioxidant capacity of milk increased (P < 0.001) with the addition of phenolic compounds from PBP in the diet. Propolis improves milk quality when added to the diet of dairy cows, but different amounts of phenolic compounds can influence the beneficial effects of PBP on dairy milk.