Steller sea lions show diet-dependent changes in body composition during nutritional stress and recover more easily from mass loss in winter than in summer

摘要: Abstract Controlled feeding experiments were undertaken with captive Steller sea lions ( Eumetopias jubatus ) to assess seasonal (winter vs. summer) physiological responses of individual animals reduced quantities and qualities food that are hypothesised occur in the wild. Eight randomly divided into two experimental groups fed isocaloric diets: Group H ate Pacific herring Clupea pallasi throughout experiment while P was switched walleye pollock Theragra chalcogramma during a 28-day restriction (after baseline) back controlled re-feeding. Diet type did not impact rates body mass lost when restricted, but influence internal energy reserve (protein lipids) predominantly used. In both summer winter, significantly more lipids less lean than phase. The response consistent predicted pattern nutritional stress physiology (i.e. protein sparing utilization lipid reserves). surprisingly high proportion consuming restricted levels pollock, which could lead muscle impairment vital organ failure on long-term basis. When given increased amounts re-feeding phase, capacity compensate for previous loss found depend season independent diet. All their gain returned pre-experimental weight summer. Some intrinsic energetic plasticity related adaptation environment may render winter an easier period recover from stress.