Dietary Glutamine Supplementation Alleviated Rumen Epithelium Oxidative Damage and Apoptosis Induced by Feed Restriction via Maintaining Mitochondrial Homeostasis in Female Yaks

In the Qinghai–Tibet Plateau, the low temperatures and the brief forage‐growing season result in starvation in yaks and cause growth retardation. We aim to study the effects of Glutamine (Gln) on rumen epithelium damage induced by feed restriction (FR) in yaks. Eighteen healthy female yaks (264.3 ± 27.83 kg) were randomly divided into three groups (6 yaks in each group). The growth experiment lasted for 60 days after 15 days of pre‐feeding. Control (Con) group was fed normal feed, feed restriction (FR) group was fed 50% feed intake of the pre‐feeding period, feed restriction + glutamine (FR + Gln) group was fed 50% feed intake during day 0–30, and was fed 50% feed intake + 1% Gln during day 31–60. The results showed that FR significantly decreased 11.66% of rumen weight and 44.26% of the rumen epithelial papillae height ( p < 0.05). However, compared with the FR group, the rumen epithelial papillae height increased significantly by 42.16% ( p < 0.05). Besides, FR decreased the Gln metabolism, adenosine triphosphate (ATP) levels, and mitochondrial DNA (mtDNA) copy number, increased the reactive oxygen species levels, inhibited the proliferation of rumen epithelial cells, and induced apoptosis ( p < 0.05), whereas Gln alleviated them ( p < 0.05). This study provided theoretical guidance for the protection of female yak farming in the Qinghai–Tibet Plateau during the cold season.