Photoperiod influences the immune status of multiparous pregnant sows and their piglets

• Published in: Journal of animal science 2006-08, Vol.84 (8), p.2072-2082
• Main Authors: Niekamp, S.R, Sutherland, M.A, Dahl, G.E, Salak-Johnson, J.L
• Format: Article
• Language: English
• Subjects: Animal productions; Animals; Biological and medical sciences; blood chemistry; Body Weight; cortisol; embryo (animal); endocrine glands; farrowing; Female; Fundamental and applied biological sciences. Psychology; immune response; immune system; Immunity - radiation effects; immunoglobulin G; Lactation; Light; Litter Size; lymphocyte proliferation; lymphocytes; Male; neutrophils; Parity; parity (reproduction); phagocytosis; Photoperiod; piglets; Pregnancy; sows; Swine - immunology; Terrestrial animal productions; Vertebrates
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jas.2005-597

Manipulation of photoperiod may provide a noninvasive, easily implemented, effective method to improve immune status and enhance the efficiency of production. The objective of this study was to evaluate the impact of manipulation of photoperiod on endocrine and immune responses of pregnant sows and their offspring. At d 83 of gestation, sows were moved to gestation stalls and kept on a photoperiod of 12 h of light:12 h of dark until d 90, when sows were assigned to a long day (LD; 16 h of light/d) or a short day (SD; 8 h of light/d) treatment. During farrowing and lactation, one-half of the sows remained on their initial photoperiod (LD:LD or SD:SD), whereas one-half were switched to the opposite treatment (LD:SD or SD:LD). Blood samples were collected from sows at d 0, 7, 14, and 21 posttreatment, 24-h postfarrowing, and the end of lactation (approximately d 21 postfarrowing). Piglets were bled at 7 and 21 d of age for immune measures. Relative to sows on LD, sows on SD had greater concanavalin A- (P = 0.003) and lipopolysaccharide- (P = 0.02) induced proliferative responses at d 7 but reduced responses at d 14. Compared with SD, sows on LD had a greater (P < 0.05) percentage of neutrophils and fewer (P < 0.05) lymphocytes at d 7, resulting in a greater (P = 0.05) neutrophil:lymphocyte ratio. Neutrophil phagocytosis was greater at d 21 in sows kept on LD. Cortisol concentrations tended to be greatest (P = 0.10) in sows on SD:SD at 24-h postfarrowing and throughout lactation. At 7 d of age, piglets on LD:SD had greater (P = 0.001) total white blood cells (WBC) and plasma cortisol (P = 0.001) relative to those on the other photoperiod treatments. Plasma immunoglobulin G was less (P = 0.001) in piglets from sows kept on SD:LD compared with the other photoperiod treatments. Piglets from sows kept on LD:LD tended to have lower total WBC (P = 0.08) at 21 d of age. Piglets from sows kept on SD:SD had greater concanavalin A- (P < 0.001) and lipopolysaccharide-induced (P