Serum concentrations of brain-derived neurotrophic factor as a potential biomarker of swine welfare.

Objective:Describe concentrations of brain-derived neurotrophic factor (BDNF) detectable in piglet sera before and after road transport, and evaluate the correlation of serum BDNF with other physiological parameters used to assess swine welfare. Animals:Commercial crosses of piglets that underwent weaning and transport at approximately 3 wk of age. Procedure:Sixteen piglets were randomly selected from a larger study for complete blood counts, serum biochemistry testing, cortisol assays, and BDNF assays. Samples were collected 1 d before transport and immediately after transport (> 30 h) under commercial conditions. We assessed the change in serum BDNF concentration; and the correlations between serum BDNF and serum cortisol, neutrophil to lymphocyte ratios (N:L), glucose, and hematological indicators of muscle fatigue. Results:Serum BDNF concentrations increased after transport (P < 0.05) and changed inversely compared to cortisol and N:L. Consistent correlations between BDNF and other physiological parameters were not observed. High inter-pig variation in serum BDNF was present at both sample times. Conclusions:Serum BDNF may be used as an additional indicator of swine welfare. Further research characterizing piglet BDNF concentrations in response to conditions promoting positive or negative affective states would be valuable. Clinical relevance:This communication discusses common hematological parameters used to quantify changes in pig welfare and introduces BDNF, which is a parameter of interest in human cognitive functioning research that may be useful for evaluating the effect of exposure to beneficial or aversive stimuli in animals. The implications of variation in sample collection, handling, and storage procedures for BDNF detection are highlighted.