New physiological indicators for welfare assessement: Cromogranin A

Non-invasive techniques, such as saliva sampling, are being developed to assess stress with minimal intervention. Chromogranin A (CgA) is co-released with epinephrine and norepinephrine and several studies suggest that salivary CgA (sCgA) is a sensitive measure of sympathoadrenal-medullary activity. The objective of this abstract is to investigate sCgA as biomarker of the stress induced after grouping in pigs. Seventy Duroc female pigs were housed in groups of 10 from 65 to 182 days of age (doa), to evaluate welfare and feed efficiency indicators. Saliva and blood samples were obtained at 66 (first day after creation of groups) and 181 doa (day before slaughter) to analyse sCGA and haemogram. Number of lesions, using an adapted Welfare Quality® protocol, were recorded at 66, 96,126,156,170 and 181 doa. Social behaviours were assessed by direct focal observations lasting 2h at 67, 96, 126, 156, 170 and 180 doa. Ratio Neutrophil/Lymphocytes (0.67±0.03 vs. 0.53±0.04) and sCgA (1.34±0.11 vs. 0.97±0.12 µg/ml) were significantly higher (P<0.05) at first compared to second sampling. Number of lesions was also significantly higher (P<0.05) at first evaluation compared to the 4 subsequent ones (0.56 vs 0.26, 0.23, 0.16, 0.17 and 0.21, respectively). No significant differences in social behaviours were found, except for a tendency of a higher number of head butts at first observation. Overall, the integration of the different indicators suggest a more compromised welfare scenario on day 66-67 (just after mixing the pigs due to hierarchy establishment) compared to day 181. Therefore, the results support sCgA as a biomarker to assess stress in pigs.