Effects of Green Tea (Camellia sinensis) Waste Silage and Polyethylene Glycol on Ruminal Fermentation and Blood Components in Cattle

The effects of green tea (Camellia sinensis) waste silage and supplemental polyethylene glycol (PEG) on rumen fermentation and blood components were studied in cattle. Six Holstein steers were fed three diets in a 3${\times}$3 Latin square design, replicated twice. One diet was a control with no added silage, and the other two diets were supplemented (20% of the dry matter) with green tea waste silage either with (PEG) or without PEG (tea). Most of the fermentation parameters including major volatile fatty acids (VFA) were not affected by the diet treatments. The concentrations of high density lipoprotein cholesterol in the PEG group and urea nitrogen in the tea and PEG groups were greater than those in the control before morning feeding. The plasma 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid equivalent concentration was not different before morning feeding, but 3 h after morning feeding, its concentrations in both the tea and PEG groups were higher than in the control. Although the concentration of plasma vitamin A in the animals was not affected by feeding green tea waste silage, the concentrations of plasma vitamin E were significantly higher in the tea and PEG groups than in the control, both before and 3 h after morning feeding. The results from the present study suggest that feeding diets containing 20% of the dietary dry matter as green tea waste silage to Holstein steers has no negative impact on their ruminal fermentation, and increases their plasma antioxidative activity and concentration of vitamin E.