Homocysteine metabolism, growth performance, and immune responses in suckling and weanling piglets.

Audet, I., Girard, C.L., Lessard, M., Lo Verso, L., Beaudoin, F., and Matte, J.J. (2015). "Homocysteine metabolism, growth performance, and immune responses in suckling and weanling piglets.", Journal of Animal Science, 93(1), pp. 147-157. doi : 10.2527/jas.2014-7872  Access to full text

Abstract

Homocysteine (Hcy), an intermediary sulfur AA, is recognized as a powerful pro-oxidant 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 56 d of age. Third-parity sows were randomly assigned to a 2 × 2 split-plot design with 2 dietary treatments (S) during gestation and lactation, S- (1 mg/kg of folates and 20 μg/kg of B12, n = 15) or S+ (10-fold S- levels, n = 16), and 2 treatments to piglets (P) within each half-litter, i.m. injections (150 μg) of B12 (P+) at d 1 and 21 (weaning) or saline (P-). Within each litter of 12 piglets, 3 P+ and 3 P- were studied for growth and Hcy metabolism and the others for immune responses. During lactation, plasma B12 decreased and were transiently greater in S+ vs S- piglets on d 1 and P+ vs P- piglets on d 7 (S × age and P × age, P < 0.05). From 14 to 21 d of age, pHcy was 33 % lower in S+P+ vs S-P- piglets (S × P 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 post-weaning G:F in S+P- piglets than in others (S × P 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 post-weaning serum IL-8 peaked earlier in S-P- vs S+P+ piglets (P × age; S × P 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) as compared to medium (17-21 µM) or to low pHcy (< 17 µM). In conclusion, the present vitamin supplements to sows and/or piglets produced variations of pHcy which 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. }

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