Short communication: Glutamine increases autophagy of liver cells in weaned calves

The objectives of this study were to determine the effects of an increased jugular supply of l-Gln on the autophagy of weaned calves. At 35 d of age, 24 Holstein calves (initial body weight of 50±0.5 kg; 35±2 d of age) were randomly allocated to 4 treatments, with each treatment including 5 male calves and 1 female calf. Holstein calves were assigned to treatments of (1) intravenous infusion of 2d of 0.85% NaCl (control group) (2) intravenous infusion of 8 g/d of L-Gln mixed with 2d of 0.85% NaCl solution, (3) intravenous infusion of 16 g/d of L-Gln mixed with 2d of 0.85% NaCl solution, and (4) intravenous infusion of 32 g/d of L-Gln mixed with 2d of 0.85% NaCl. The infusion was administered 2h/d for 7 consecutive days starting on d 1 after weaning. Feed and water were freely available to all calves. All calves were killed on d 7 postweaning to measure the autophagy of liver cells. The level of autophagy in liver cells was improved when the Gln infusion dose increased.