Plasma triglyceride levels correlate with body weight, age and gender influence body weight changes in Spermophilus lateralis during prehibernation and hibernation

Abstract

Our experimental groups consisted of a total 16 male (M) and 15 female (F), juvenile and adult Spermophilus lateralis. This study evaluated weight gain rate (WGR) and mass-specific rate of gain (MSRG) during prehibernation, and weight loss rate (WLR), mass-specific rate of loss (MSRL) plus changes in the levels of plasma triglyceride (TG) during hibernation in these squirrels (SQ). Between January and March, the plasma samples were obtained from 26 SQ. Plasma TG was determined enzymatically, and it averaged 189 mg% with no significant difference in gender. Correlations were observed between plasma TG and sacrificed body weight ( r = 0.441, p < 0.05), and between plasma TG and MSRL ( r = 0.409, p < 0.05), although plasma TG was not correlated with WLR during hibernation. Juvenile female SQ had a higher WGR than adult female SQ, but no significant difference was found between juvenile and adult males. Both juvenile males and females showed a significantly higher MSRG than adult male and female SQ. Conversely, adult male SQ had a higher WLR and MSRL than juvenile male SQ, but no significant difference was observed between adult and juvenile females. Moreover, juvenile male SQ showed a significantly lower WLR but not MSRL than juvenile females. For these animals, our results suggest that the age factor influences on WGR and MSRG during prehibernation, and also influences on WLR and MSRL during torpor.