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High ambient temperature exposure and sanitary challenge

Pigs are and will be more and more frequently exposed to high ambient temperatures because of the growth of pig production in tropical and sub-tropical areas and the projected consequences of warming climate in livestock production. In such conditions, pigs are also more exposed to diverse sanitary challenges. The inflammatory responses associated with a sanitary challenge induce important physiological and metabolic disturbances. Little is known about heat acclimation and cross tolerance against inflammatory challenges in growing pigs. The objectives of this work were:

• to evaluate the physiological responses and growth performance of growing pigs exposed to high ambient temperature
• to provide new knowledge on the effects of high ambient temperature on the ability of growing pigs to overcome an inflammatory challenge.

High temperature exposure might be beneficial to limit the physiological and metabolic disturbances

Our findings showed that high ambient temperature exposure (30°C vs 24°C) induced a two-step response. The short term response is characterized by a greater internal temperature, greater body heat losses and reduced heat production mainly caused by reduced feed intake. After 24 to 48 h of exposure to high temperature, during the acclimation process, bodycore temperature decreases gradually. Lower release of thyroid hormones and cortisol into the blood circulation contributes to decrease metabolic heat production.

Surprisingly, our results show that acclimation to high ambient temperature might be beneficial in improving the capacity of pigs to limit the physiological and metabolic disturbances caused by an inflammatory challenge induced by repeated administrations of Escherichia coli lipopolysaccharide. Lower plasma concentrations of pro inflammatory cytokines and acute phase proteins for heat acclimated pigs in response to the inflammatory challenge seems to confirm this hypothesis. Moreover, despite being lower than at thermo neutrality, growth rate and, lipid and protein depositions were less impacted by the inflammatory challenge in pigs previously acclimated to high temperature. To our knowledge, for the first time, our results describes  such an interaction between high ambient temperature and an inflammatory challenge in pigs.

Evaluate the effects of extreme thermic events on pigs performance

Studies are currently under way to evaluate the short term and long term effects of extreme thermic events, like heat waves, on growth performance of pigs. These works are carried out in the PigChange project (MP ACCAF). Further studies will be necessary to determine if such adaptation could improve resistance and tolerance of pigs towards thermic and sanitary challenges similar to those encountered in farm conditions.

This work was conducted as part of the PhD of Paulo H. Reis Furtado Campos between 2011 and 2014 and was funded by the Brazilian government (CAPES scholarship), Phase department and the ANR project PigFeed.

Bibliography

• Reis Furtado Campos, P. H., Noblet, J., Jaguelin-Peyraud, Y., Gilbert, H., Mormède, P., de Oliveira Donzele, R. F. M., Donzele, J. L., Renaudeau, D. (2014). . Thermoregulatory responses during thermal acclimation in pigs divergently selected for residual feed intake. International journal of biometeorology, 58 (7), 1545-1557. (DOI)
• Reis Furtado Campos, P. H., Merlot, E., Damon, M., Noblet, J., Le Floc'h, N. (2014). . High ambient temperature alleviates inflammatory response and growth depression in pigs challenged with Escherichia coli lipopolysaccharide. Veterinary Journal, 200 (3), 404-409. (DOI)
• Reis Furtado Campos, P. H., Labussière, E., Hernandez Garcia, J. C., Dubois, S., Renaudeau, D., Noblet, J. (2014). . Effects of ambient temperature on energy and nitrogen utilization in lipopolysaccharide-challenged growing pigs. Journal of Animal Science, 92 (11), 4909-4920. (DOI)
• Reis Furtado Campos, P. H., Merlot, E., Damon, M., Noblet, J., Le Floc'h, N. (2013). . Effects of high ambient temperature on responses of pigs to an inflammatory challenge. In: Book of Abstracts of the 64th Annual Meeting of the European Federation of Animal Science (p. 436). EAAP Book of Abstracts, 64. Presented at 64th Annual Meeting of the European Federation of Animal Science (EAAP), Nantes, FRA (2013-08-26 - 2013-08-30). Wageningen, NLD : Wageningen Academic Publishers. (Présentation orale- Best Presentation Award Physiology Section) [lien]
• Mottet, A., Renaudeau, D., Soussana, J.-F. (2014). Accompagner l'adaptation de l'élevage. Pour la Science (437), 74-77. [lien]
• Reis Furtado Campos, P. H. (2014). Réponses physiologiques et zootechniques à la chaleur en interaction avec le statut sanitaire chez le porc en croissance (Thèse de doctorat). [lien]
• Le Floc'h, N., Campos, P., Merlot, E., Renaudeau, D., Noblet, J. (2015). Postprandial nutrient metabolism in lipopolysaccharide-challenged growing pigs reared at thermoneutrality or acclimated to high ambient temperature. In: 7th European symposium of porcine health management : proceedings (p. 138). Presented at 7. European symposium of porcine health management (ESPHM), Nantes, FRA (2015-04-22 - 2015-04-24). [lien]

Contact

Nathalie Le Floc'h (nathalie.lefloch[at]rennes.inra.fr)