After the ban on the use of growth-promoting antibiotics in the EU in 2006, post-weaning diarrhoea (PWD) cannot be controlled by those means, and consequently other safer alternatives to feed antimicrobials have been sought. Ways must also be found to improve the healthiness and safety of animal products reaching the consumer, and therefore safe natural products (e.g. probiotics, plant extracts, etc.) are at the centre of interest in this field. In this study were tested plants (clove, Caucasian wingnut, windflower) which showed in vitro strong inhibitive activity against ETEC, therefore the aim was to study their effects on clinical status, gut microbiota and immune response in weaned pigs infected by ETEC.
For the experiment were used 60 clinically healthy Yorkshire pigs, genetically susceptible to K88(F4)ac infection, which were divided into 5 groups of 12 animals each (3 experimental groups, infected and negative controls). 1% of plant material – Eugenia caryophyllata (clove), Pterocarya fraxinifolia (Caucasian wingnut) and Anemone nemorosa (windflower) were administered to piglets in experimental groups into the feed from 14th to 35th day of life. On the day of weaning (28th day) were all animals, except of those in negative control, infected with E.coli O149:K88ac ent . Clinical status was monitored daily. Samples of blood, jejunal and ileal content and tissue were taken on 3rd and 7th day after infection. Microbiological, hematological and immunological analyses were performed.
Eugenia and Pterocarya significantly decreased incidence and duration of diarrhoea, as well as fecal score. Both plants also significantly decreased numbers of E. coli adhered to the jejunal and ileal mucosa as compared to infected control. In the Eugenia group was noted significant increase of CD4 lymfocyte proportion in intraepithelial part and lamina propria of jejunal mucose, as well as in peripharal blood in comparison with infected and negative controls. CD4 and CD8 subpopulations of lymphocytes in lamina propria of the jejunal wall were significantly increased on 7th day in Pterocarya group as compared to negative control. Pterocarya also significantly increased CD4:CD8 ratio in peripheral blood in comparison with infected and negative controls. Phagocytic activity and metabolic activity of phagocytes was significantly higher in this group. Anemone did not show positive influence on the course of post-weaning diarrhoea, microbiological and immunological parameters in tested pigs.
Both plants, Eugenia and Pterocarya can represent effective alternatives to feed antimicrobials for the use in prevention of PWD in pigs, but further studies are necessary.
D Mudronov, R Nemcov, S Gancarcikov, V Revajov, J Pistl, J Koscov, V Bulec, A Bomb. Plant additives as an alternative to feed antimicrobials in the prevention of postweaning diarrhoea in pigs. IPVS 2012.