Impacts of a Balanced Omega 6:3 Diet on Fatty Acid Deposition in White and Brown Adipose Tissue and Circulating Plasma in the Hibernating Arctic Ground Squirrel

Abstract

Hibernators, such as arctic ground squirrels (AGS), fuel the majority of all their metabolic needs from fat deposits through the hibernation season (Dark 2005). Natural fatty acid profiles of free‐ranging AGS have omega 6:3 ratios close to 1:1, showing a far higher consumption of omega 3 fatty acids than captive animals, fed a standard Mazuri rodent chow (which have omega 6:3 ratios close to 8:1). Specific concentrations of omega 6 polyunsaturated fatty acids (PUFAs) enhance hibernation (Frank 2008) and absence of essential fatty acids reduce time in torpor (Florant 1993). To our knowledge, only three studies have investigated the impact of omega 3s on hibernation physiology (Giroud 2018, Frank 2004, and Hill and Florant 2000). In other species, high consumption of omega 3 fatty acids show dose‐dependent lowering of serum triglycerides with other health benefits (Balk 2006). How increased consumption of omega 3 fatty acids impact brown adipose tissue deposition and fatty acid profiles in tissue and serum related to storage and utilization in hibernating AGS is unknown.A group of wild juvenile AGS (female=12, male=12) were fed either a test diet, with an omega 6:3 ratio of 1.3:1, or a standard chow control diet, with an omega 6:3 ratio of 8:1, from mid‐July (after trapping and quarantine) till animals entered hibernation (August–September). Tissues were collected mid‐December at three specific physiological states of hibernation: early torpor, late torpor and arousal. Total lipid fatty acid profiles of plasma, brown adipose and white adipose tissue were quantified by GC analysis. Axillar brown adipose tissue was dissected and weighed.Preliminary results show a significant increase in axillar brown adipose tissue mass in the omega 6:3 balanced diet animals (p<0.038). Preliminary data also indicates increased percentages of circulating levels of polyunsaturated fatty acids in plasma of hibernating AGS compared to summer or fall animals (p<0.01). Full fatty acid analysis is pending.In conclusion, our preliminary results indicate a balanced diet of omega 6:3 (1:3:1) in hibernating Arctic Ground Squirrels may enhance brown adipose tissue deposition.Support or Funding InformationThis work was supported by NIH 20GM103395, UL1GM118991, TL4GM118992, or RL5GM118990. This work was performed in conformance with the FASEB Statement of Principles for animals used in research.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.