Antimicrobials added to the feed of weaned piglets at two ages improves the molecular expression of intestinal barrier proteins

Abstract

Context Weaning is the most critical period during a pig’s life, because it is a challenge with the change of environment, and the digestive system is not adapted to a solid diet at the time of weaning, favouring the appearance of intestinal disorders, infections and diarrhoea. Aims To quantify the gene abundance of intestinal barrier tight junction proteins in pigs fed diets added with antimicrobials and weaned at two ages. Methods A total of 150 pigs weaned at two ages (21 and 28 days) were distributed into groups: Control Diet 1 (D1-Ctrl) without antimicrobial; Diet 2 (D2-Ant): Ctrl with an antibiotic (bacitracin zinc); Diet 3 (D3-Prob): Ctrl with Bacillus subtilis PB6 (PTA-6737); Diet 4 (D4-OEO): Ctrl with oregano essential oil (OEO; Lippia origanoides); Diet 5 (D5-OA): Ctrl with a mixture of organic acids. On post-weaning Days 1, 15 and 30, pigs were euthanised, and a portion of the jejunum was removed to assess the gene abundance of the intestinal tight junction proteins (occludin-OCLN, zonula occludens-ZO-1 and claudins-CLAU) that were measured by qPCR. Key results The pigs fed the diet with the addition of D3-Prob and D4-OEO showed a higher abundance (P < 0.05) of intestinal barrier tight junction protein genes (CLAU-1, CLAU-4, OCLN, ZO-1) compared with the other diets. This abundance was observed in both piglets weaned early, at 21 days, and later at 28 days of age, where, in addition, a statistically significant difference between weaning ages (P < 0.05) was evidenced in favour of later weaning. Conclusions The addition of probiotics in the growth phase, together with weaning at 28 days of age, have a favourable impact on the intestinal digestive function of pigs, being able to influence morphometric and productive parameters, and serve as a basis for the analysis of molecular research related to intestinal health. Implications This research provides a basis for the use of natural nutritional alternatives, such as probiotic bacteria, as alternatives to growth-promoting antibiotics in the feed of growing pigs; in addition to encouraging a better adaptation of the piglet to the post-weaning phase, through late weaning.