Validating a New Indicator of Welfare for Grizzly Bears

The field of animal welfare is always advancing as we discover and validate new means of assessing individual wellbeing. At the Detroit Zoological Society, we are particularly interested in establishing comprehensive physiological measures. Measures of oxidative stress may allow for exploration of both positive and negative life experiences. Specifically, we can use fecal samples to examine concentrations of 8-hydroxy-2’-deoxyguanosine (8-OHdG, a by-product of DNA damage). We hypothesized that adrenal activity contributes to oxidative stress and subsequent DNA damage. The temporary housing of three adult male grizzly bears (Arctos horribilis) in a smaller habitat while their primary habitat underwent renovations and expansion provided an opportunity for preliminary validation of 8-OHdG concentrations against other validated physiological measures (fecal glucocorticoid metabolites or FGMs) and behavioral data. We found that concentrations of 8-OHdG increased significantly as FGM concentrations increased. This supports the hypothesized relationship between adrenal activity and DNA damage. The relationship between 8-OHdG and behavior was more complicated to assess. We initially predicted that 8-OHdG would be lower when individuals demonstrated higher rates of positive social interactions. One bear demonstrated no relationship between 8-OHdG and positive social interactions, another bear demonstrated increases in 8-OHdG concentrations with increased positive social interactions, and the last bear demonstrated the predicted decreases in 8-OHdG concentrations with increased positive social interactions. This conflicting evidence lends preliminary support for 8-OHdG as a non-invasive animal welfare measure, but we look forward to continued validation efforts.

https://doi.org/10.3390/jzbg2030022