How spray dried plasma can replace antibiotics at weaning: in-vitro effects of plasma on intestinal porcine epithelial cells.

The weaning period is a challenging time for piglets. Their feed intake decreases and about 20% of the piglets suffer from post weaning diarrhoea (PWD). PWD is an important cause of economic loss, due to high morbidity and mortality, decreased growth, and costs for medication. Control of PWD is often done by antibiotics or by inclusion of zinc oxide in feed. PWD is mainly caused by the abrupt loss of protection by maternal antibodies which prevents colonization of the intestine with pathogens like the enterotoxigenic bacterium E. coli F4+ (K88)(ETEC), which is the most common cause of PWD.

Spray dried plasma (SDP) is widely applied in weaning diets to support the milk-to-feed transition of the piglet. Multitudes of studies on plasma show the beneficial effects on piglet performance and indicate that SDP may be a good alternative for antibiotic treatment. In the present study gene expression analyses were conducted to elucidate biological mechanisms by which SDP induces beneficial effects in the intestine of weaned piglets.

Cultured porcine enterocytes (Intestinal Porcine Epithelium Cells; IPEC-J2) were incubated with SDP products and controls, and were or were not challenged with ETEC bacteria. The expression level of genes (coding for 14.000 unique proteins) was measured with a microarray. Clusters of genes that were differently expressed were identified. Bioinformatics programs were used to identify biological processes affected by SDP.

The in-vitro results indicate that SDP steers a variety of biological processes in the enterocytes of pigs inflamed by ETEC. From the regulated gene clusters it appears that SDP

1) protects against infectional damage and maintains the barrier function of the intestinal epithelial layer;

2) improves alertness (recognition by Toll-like receptors) and function of the immune system;

3) stimulates cell-renewal in the epithelial wall; and

4) tempers Interferon and IL6–induced inflammatory reactions in the intestine which may prevent overreaction of the immune system.

A part of the identified biological processes and effector molecules are similar to those observed after treatment with antibiotics and zincoxide. These results indicate that similar mechanisms contribute to the observed beneficial effects and confirm the statement that SDP products are a good alternative for antibiotics in reducing PWD.

The need to reduce antibiotic treatment stimulates the search for alternative management, feeding and treatment strategies. The present study gives a methodological approach to screen for candidate in-feed alternatives and secondly hints to mechanisms whereby SDP supports the gut health around weaning.

Disclosure of Interest: None Declared.