Lactogenic immunity provides oro-gastric protection to the offspring against infectious pathogens. The conventional swine production systems are weaning at an immunologically immature age (3–4 weeks) of the piglets. The weaning deprives a continued supply of protective lactogenic antibodies when piglets are placed in a new environment with increased risk of enteric bacterial infections. Post-weaning diarrhoea (PWD), are usually treated and/or prevented with antibiotics and/or zinc oxide in the piglet feed. However extensive use of antibiotics and zinc oxide in intensive animal production is unwanted as it may promote microbial antibiotic resistance and pose environmental problems. Recently, in an experimental model of PWD, it was observed that oral administration of purified porcine immunoglobulin G (ppIgG) from pooled natural pig plasma could reduce enteric infection. Two separate factorial experiments involving 12 (10.8 ± 1.8 kg BW, from 2 litters) and 18 (7.3 ± 1.0 kg BW, from 2 litters) pigs for the first and second experiments, respectively, were conducted. In both experiments, piglets were carriers of the dominant gene encoding for intestinal F4 fimbriae receptors. In experiment 1 (long term, low IgG dose pilot study) 750 mg/day of ppIgG was provided orally for five days before and 10 days post weaning. In experiment 2 (short term, high IgG dose) 1.9 g of ppIgG was given orally twice daily for seven days after weaning/challenge. Experiment 2 also comprised a group receiving dietary zinc oxide for 10 days after weaning. Piglets were weaned from the sows at day 28 of age and challenged with on two days 29 and 30 of age.
Oral ppIgG accelerated clearance of faecal haemolytic bacteria in pigs challenged with E. coli in comparison with pigs not receiving ppIgG. This effect was observed upon feeding ppIgG for seven days post-weaning suggesting that ppIgG does not have to be used prophylactically for several days pre-weaning. Furthermore, the effect of oral administration of ppIgG for seven days post-weaning was equal to or better than that of dietary zinc oxide in reducing diarrhoea symptoms and in clearing faecal haemolytic bacteria for 14 days post-weaning.
These observations warrant future trials of dietary ppIgG in intensive swine production units to establish its performance as an alternative to dietary antibiotics and zinc oxide for preventing PWD.
Hedegaard, C. J., Lauridsen, C., and Heegaard, P. M. (2017). Purified natural pig immunoglobulins can substitute dietary zinc in reducing piglet post weaning diarrhoea. Veterinary Immunology and Immunopathology, 186, 9-14. https://doi.org/10.1016/j.vetimm.2017.02.001