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.

Concentrations sériques du facteur neurotrophique dérivé du cerveau en tant que biomarqueur potentiel du bien-être des porcs. Objectif: Décrire les concentrations de facteur neurotrophique dérivé du cerveau (BDNF) détectables dans les sérums de porcelets avant et après le transport routier, et évaluer la corrélation du BDNF sérique avec d'autres paramètres physiologiques utilisés pour évaluer le bien-être des porcs. Animaux: Croisements commerciaux de porcelets qui ont été sevrés et transportés à l'âge d'environ 3 semaines. Procédure: Seize porcelets ont été sélectionnés au hasard dans une étude plus vaste pour une numération globulaire complète, des tests de biochimie sérique, des dosages de cortisol et des dosages de BDNF. Les échantillons ont été prélevés 1 jour avant le transport et immédiatement après le transport (> 30 h) dans des conditions commerciales. Nous avons évalué la variation de la concentration sérique de BDNF; et les corrélations entre le BDNF sérique et le cortisol sérique, les rapports neutrophiles/lymphocytes (N:L), le glucose et les indicateurs hématologiques de la fatigue musculaire. Résultats: Les concentrations sériques de BDNF ont augmenté après le transport (P < 0,05) et ont changé inversement par rapport au cortisol et à N:L. Des corrélations cohérentes entre le BDNF et d'autres paramètres physiologiques n'ont pas été observées. Une forte variation inter-porcs du BDNF sérique était présente aux deux moments d'échantillonnage. Conclusions: Le BDNF sérique peut être utilisé comme indicateur supplémentaire du bien-être des porcs. Des recherches supplémentaires caractérisant les concentrations de BDNF chez les porcelets en réponse à des conditions favorisant des états affectifs positifs ou négatifs seraient utiles. Pertinence clinique: Cette communication traite des paramètres hématologiques courants utilisés pour quantifier les changements dans le bien-être des porcs et présente le BDNF, qui est un paramètre d'intérêt dans la recherche sur le fonctionnement cognitif humain qui peut être utile pour évaluer l'effet de l'exposition à des stimuli bénéfiques ou aversifs chez les animaux. Les implications pour la détection par le BDNF des variations dans les procédures de collecte, de manipulation et de stockage des échantillons sont mises en évidence.(Traduit par Dr Serge Messier).

Physiological response of weaned piglets to two transport durations observed in a Canadian commercial setting.

Observational studies describing the impact of transport duration on weaned piglet welfare are limited. Current Canadian transport regulations are heavily informed by studies involving market hogs. Due to physiological differences between weaned piglets and market hogs, additional data on their response to transport are needed for age-specific evidence-based recommendations. A cohort study was conducted to describe and compare mortality, injury, weight change, hematological or biochemical changes in hydration, muscle injury and stress response observed in weaned piglets undergoing short duration (SD, <3 h), or long duration (LD, >30 h) commercial summertime transport events. Data collection on 440 of 11,434 transported piglets occurred the morning of the day before transport (T0), at arrival (T1) and approximately 3 to 4 d (78 to 93 h) after arrival at the nursery barn (T2). Low mortality occurred over all transport events (0.06%) with no association observed between transport duration and odds of death during transport (P = 0.62). The incidence of lameness between T0 and T1 was low (1.84% of the 435 focal piglets scored) with all lameness cases identified as mild in severity. Lesions on ears and skin were more prevalent than other injury types after transport (T1) and may have been related to mixing aggression associated with weaning rather than transport alone. LD piglets weighed 0.39 kg less than SD piglets at T1 (P < 0.01), but no difference in group weight was observed at T2 (P = 0.17). Hematological and biochemical differences were present between groups at T1. LD piglets had increased hematocrit levels compared with SD piglets (P = 0.01), suggesting increased body water losses. SD piglets showed greater levels of muscle injury compared with LD piglets including elevated aspartate aminotransferase (P < 0.01) and creatine kinase (P < 0.01). However, these parameters were within normal reference ranges for piglets of this age group. Indicators of physiological stress response including cortisol and neutrophil to lymphocyte ratios were elevated in SD piglets compared with LD piglets (P = 0.02 and P < 0.01, respectively). The results of this study demonstrate that both short and long transport durations can result in detectable physiological changes in weaned piglets. The overall impact of these durations on piglet welfare should be further explored by analyzing behavioral time budgets during and after transport.