A Model of early vitamin deficiency in a hibernator, the 13-lined ground squirrel

Wildlife Management;Ground squirrels

Sprenger, Ryan J.Kurtz, Courtney ;

University of Wisconsin

关键词: Wildlife Management;    Ground squirrels;   

Others  :  https://minds.wisconsin.edu/bitstream/handle/1793/75217/Sprenger%2c%20Ryan.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: University of Wisconsin

【 摘 要 】

Hibernators, such as the 13-lined ground squirrel (Ictidomys tridecemlineatus), undergodramatic changes in adipose tissue mass during their circannual cycle. Retinoic acid(RA), the biologically active derivative of vitamin A, plays key roles in the developmentand growth of adipose tissue. We developed a model of early vitamin A deficiency injuvenile ground squirrels to determine RA’s effects on the ability to adequately buildadipose mass prior to the first season of hibernation. Deficient squirrels (VAD) weremaintained on the diet until 8 weeks of age when severe symptoms of hypovitaminosiswere observed, including stunted growth and limb weakness. Liver retinoid analysisshowed that these animals had essentially no retinoid stores. Even when placed on anormal diet, the VAD squirrels never reached the retinoid stores of controls. Controlretinoid stores were high compared to other rodents, but in the normal range for thespecies. Serum retinol binding protein (RBP) was not affected by diet, althoughdecreased levels were found in torpid hibernators. Early deficiency was associated withdecreased mass of white (WAT) and brown (BAT) adipose tissue depots, decreasedexpression of resistin, altered seasonal expression of the RXR-β retinoid receptor andincreased expression of BAT uncoupling protein. Our results suggest that groundsquirrels require high levels of retinoids for normal function and are especiallysusceptible to deficiency as it affects the seasonal accumulation of adipose tissue.