Comparison of Blood Immunity, Antioxidant Capacity and Hormone Indexes in Finishing Bulls Fed Active Dry Yeast (Saccharomyces cerevisiae) and Yeast Culture

摘要

This study aims to compare the effect of active dry yeasts (ADY) and yeast cultures (YC) on blood immunity, antioxidant capacity and hormone indexes, and also to clarify the relationships between blood indexes and feed intake, blood indexes and beef tenderness in finishing bulls fed a high-concentrate diets. The results indicated that ADY supplementation decreased serum concentration of total antioxidant capacity (TAOC) (p < 0.05), superoxide dismutase (SOD) (p < 0.05) and catalase enzyme (CAT) (p < 0.05), but had no significant effect on concentration of malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) (p > 0.05). YC supplementation decreased activity of SOD (p < 0.05) and had no effect on other indexes above (p > 0.05). Both ADY and YC had no significant effect on serum concentration of IgA, IgG and IgM compared to CON (p > 0.05). Both ADY and YC elevated the plasma ghrelin concentration (p < 0.05), while have no effect on leptin, triiodothyronine (T 3 ) and thyroxine (T 4 ) (p > 0.05). There was a negative correlation between dry matter intake (DMI) and CAT (r = -0.374, p < 0.05), and a positive correlation between DMI and ghrelin (r = 0.306, p = 0.027). There was a negative correlation between shear force and ghrelin level (r = -0.384, p < 0.05). There are differences between effects of ADY and YC on antioxidant indexes and, CAT and ghrelin contributed to regulate DMI of finishing bulls fed high-concentrate diets, and the improved beef tenderness is related to elevated ghrelin concentration.