Nutritional Gel Supplementation Reduces Weight Loss and Mortality in Mice Infected with Influenza A/PR/8/34 Virus

Abstract

Influenza virus A (IAV) places a high-burden on public health. Studies of IAV commonly use mice to model the response of the immune system in vivo. Complications of IAV studies include anorexia and dehydration with subsequent weight loss resulting in early removal of mice from a study based on euthanasia criteria. To reduce the number of mice prematurely removed from an experiment, we assessed various support strategies in mice infected with IAV: 1) standard of care (SOC), 2) nutritional gel (NG), 3) subcutaneous fluids, 4) oral gavage - nutritional formula (OG ICU), and 5) oral gavage - PBS (OG PBS). We hypothesized that when compared to the SOC, supplementation with NG would lead to decreased weight loss and mortality in mice infected with IAV without impacting the initial immune response. For assessment of NG, both male and female C57Bl6/J mice were infected with mouse-adapted IAV, A/PR/8/34, at low, medium or high doses. SQ fluids, OG ICU and OG PBS were assessed in male mice infected with the middle influenza dose. Euthanasia criteria removed mice at 30% weight loss. Mice supplemented with NG and subcutaneous fluids lost significantly less weight and the NG group had a significant reduction in mortality. Supplementation with OG ICU and PBS had no benefit. Supplementation with NG did not alter the pulmonary recruitment of immune cells as measured with cell counts and flow cytometry of cells recovered in bronchoalveolar lavage fluid. In summary, the results of this study show mice infected with mouse-adapted IAV that are supplemented with NG have reduced weight loss and mortality. These results suggest that NG should be considered as a support strategy for mice infected with IAV.