title: Homocysteine metabolism, growth performance, and immune responses in suckling and weanling piglets.
abstract: Homocysteine (Hcy), an intermediary sulfur AA, is recognized as a powerful prooxidant with deleterious effects on physiological and immune functions. In piglets, there is an acute 10-fold increase of plasma concentrations of homocysteine (pHcy) during the first 2 wk of life. This project aimed to maximize pHcy variations within physiological ranges using typical supplies of folates and vitamin B12 (B12) to sows and piglets. Growth, immune response, and Hcy metabolism of piglets were studied until piglets reached 56 d of age. Third-parity sows were randomly assigned to a 2 × 2 split-plot design with 2 dietary treatments during gestation and lactation, S(-) (1 mg/kg folates and 20 µg/kg B12, n = 15) and S(+) (10-fold S(-) levels, n = 16), and 2 treatments to piglets within each half litter, intramuscular injections (150 µg) of B12 (P(+)) at d 1 and 21 (weaning) and saline (P(-)). Within each litter of 12 piglets, 3 P(+) and 3 P(-) piglets were studied for growth and Hcy metabolism, and the others were studied for immune responses. During lactation, plasma B12 decreased and was transiently greater in S(+) vs. S(-) piglets on d 1 and P(+) vs. P(-) piglets on d 7 (sow treatment × age and piglet treatment × age; P < 0.05). From 14 to 21 d of age, pHcy was 33% lower in S(+)P(+) vs. S(-)P(-) piglets (sow treatment × piglet treatment interaction; P < 0.05). At 56 d of age, hepatic B12 was greater and pHcy was lower for P(+) vs. P(-) piglets (P < 0.05). No treatment effect was observed on growth except for a lower postweaning G:F in S(+)P(-) piglets than in others (sow treatment × piglet treatment interaction; P < 0.05). Positive correlations were observed between pHcy and growth (r > 0.29, P < 0.05) before and after weaning. Antibody responses to ovalbumin and serum tumor necrosis factor-α were not affected by treatments, but postweaning serum IL-8 peaked earlier in S(-)P(-) vs. S(+)P(+) piglets (piglet treatment × age; sow treatment × piglet treatment interaction, P < 0.05). Proliferation of lymphocytes in response to the mitogen concanavalin A tended to be lower in culture media supplemented with sera from S(-) vs. S(+) piglets (P = 0.081) and P(-) vs. P(+) piglets (P = 0.098), and the reduction of response was more marked (P < 0.05) with high (>21 µM) compared to medium (17 to 21 µM) or low (<17 µM) pHcy. In conclusion, the present vitamin supplements to sows and/or piglets produced variations of pHcy that were not apparently harmful for growth performance of piglets. The greater pHcy, particularly prevalent in S(-) and/or P(-) piglets, had negative effects on some indicators of immune responses, suggesting that these young animals may be immunologically more fragile.
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, 2000 College Street, Sherbrooke, Québec J1M 0C8, Canada.
authors.forename: I
authors.initials: I
authors.lastname: Audet
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, 2000 College Street, Sherbrooke, Québec J1M 0C8, Canada.
authors.forename: C L
authors.initials: CL
authors.lastname: Girard
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, 2000 College Street, Sherbrooke, Québec J1M 0C8, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Lessard
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, 2000 College Street, Sherbrooke, Québec J1M 0C8, Canada Department of Veterinary Science for Health, Animal Production, and Food Safety, University of Milan, Milan 20133, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Lo Verso
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, 2000 College Street, Sherbrooke, Québec J1M 0C8, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Beaudoin
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, 2000 College Street, Sherbrooke, Québec J1M 0C8, Canada jacques.matte@agr.gc.ca.
authors.forename: J J
authors.initials: JJ
authors.lastname: Matte
mesh_terms: D000367:Age Factors; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D003208:Concanavalin A / Q000494:pharmacology; D004032:Diet / Q000662:veterinary*; D005260:Female; D006710:Homocysteine / Q000097:blood / Q000378:metabolism*; D016209:Interleukin-8 / Q000097:blood; D007774:Lactation / Q000502:physiology; D008214:Lymphocytes / Q000502:physiology; D011247:Pregnancy; D034421:Sus scrofa / Q000254:growth & development* / Q000276:immunology* / Q000378:metabolism; D013552:Swine; D014805:Vitamin B 12 / Q000097:blood; D014886:Weaning
chemical_list: D016209:Interleukin-8; D006710:Homocysteine; D003208:Concanavalin A; D014805:Vitamin B 12
keywords: folic acid; homocysteine; immune response; piglet; sow; vitamin B12