Supplementation with Yucca schidigera improves antioxidant capability and immune function and decreases fecal score...

Yucca schidigera (YS) is a species of plant rich in antimicrobials, antioxidants, and immunomodulators. It has been used as feed additive to improve animal performance and decrease methane emissions in cattle. However, few studies have evaluated YS in dairy calves. In this study, we evaluated the effects of YS on the growth performance, antioxidant capacity, and immune function in dairy calves before weaning. We randomly assigned 40 newborn female Holstein calves (4 d old; 40 ± 5 kg of body weight) to 1 of 4 treatments (n = 10 per treatment), which were fed 0, 3, 6, or 9 g/d of YS powder. The YS allowance was mixed into milk or milk replacer and fed twice daily. Dry matter intake (both liquid and starter feed) and fecal score were recorded daily, and body weight, withers height, body length, and heart girth were measured at 4, 14, 28, 42, and 60 d of age. Blood was sampled from the jugular vein at 14, 42, and 60 d of age after the afternoon feeding for analysis of serum antioxidant capacity and immune function. Feeding YS did not affect dry matter intake, but decreased the feed-to-gain ratio with a quadratic dose effect. Over the whole study period, the average daily gain tended to linearly increase with the increasing YS doses, and it was 6.8% higher in diets supplemented with 9 g/d of YS than in the basal control diet without YS. The YS supplementation linearly decreased fecal score in a dose-dependent manner, and the frequency of diarrhea was significantly decreased as the YS supplementation increased throughout the whole study period. The YS supplementation also linearly decreased maleic dialdehyde concentration in the serum compared with the control group. The activity of catalase tended to linearly and quadratically increase, and that of glutathione peroxidase increased linearly with the increased YS supplementation. Serum concentrations of IgA and IgG increased linearly with the increased YS supplementation, and that of IgG tended to increase quadratically. To the best of our knowledge, this is the first study that demonstrated that feeding YS to young calves could improve growth, feed efficiency, and immunity, and decrease fecal score and diarrhea. The results of this study indicated that feeding YS at 9 g/d may be recommended to benefit dairy calves before weaning.