2000; Soppela et al. 2008) and may have signaled that energy reserves were depleted. The positive correlation between leptin and the amount of subcutaneous fat (back fat) was fairly low (r = 0.22), which suggests that leptin was not a strong predictor of back fat thickness in the sampled bison. We found that NEFA (indicator fat metabolism) and BUN (indicator of protein intake) were the most important indicators of nutrition in relation to infection intensity (Table1c). This evidence concerns the gene LEP and infection.