Antillean manatees (Trichechus manatus) tolerate acute food deprivation associated with a modest reduction in body mass

Abstract

Acute food deprivation induces metabolic shifts toward a greater reliance on lipid metabolism to sustain homeostasis in marine mammals. Lipid utilization depends on diet, metabolic rate, environmental conditions, and food availability. Antillean manatees ( Trichechus manatus) are aquatic herbivores with two-layered fat deposits that can reduce their metabolic rate by 23% when fasting. However, the contributions of lipid metabolism during fasting and refeeding in manatees remain poorly understood. Three juvenile Antillean manatees under human care were food deprived for 64 hours under close medical watch, then refed. Body mass (BM) was measured before and after acute food deprivation over the course of the four days of the study. Plasma samples were collected 16 hours post-prandial control, 40 and 64 hours after food deprivation, and 16 hours post-re-feeding. Prior to deprivation, mean BM was 107.3 ± 5.2 kg, and 100.1 ± 4.3 kg after deprivation. LDL increased after 40 hours of fasting and decreased at 64 hours, whereas HDL peaked at 60 hours post-fast and decreased during refeeding. TG and VLDL increased after refeeding; however, there were no significant changes between deprivation and refeeding in the lipid panel suggesting that 64 hours of acute food deprivation is well tolerated. These data provide an insight to the metabolic tolerance of the Antillean manatee that may experience acute periods of food deprivation as animals migrate across habitats and/or as they experience habitat loss or seasonal food scarcity. I. Ruiz was supported by NIH NIGMS URISE grant T34 GM145511. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.