Efficacy of ground herb-based and essential oil-based phytobiotics on the intestinal health and performance of nursery pigs challenged with F18+Escherichia coli

This study aimed to evaluate the efficacy of using ground herb-based phytobiotics and essential oil-based phytobiotics in pig diets on intestinal health and growth performance (GP) of nursery pigs challenged with F18+Escherichia coli. Forty nursery pigs (6.4 +/- 0.1 kg) at 21 d of age were individually housed and assigned to 4 dietary treatments in a randomized complete block design, with body weight and sex as blocking factors. Basal diets were fed to pigs for 28 d in 3 phases. Treatments were negative control (NC): basal diet, non-challenged; positive control (PC): basal diet, challenged with F18+E. coli; HP: PC + 1% ground herb-based phytobiotics (Salcochek Pro, Ayurvet Limited, Kaushambi, India); EP: PC + 1% essential oil-based phytobiotics (Liq-biotic, Ayurvet Limited). The GP was recorded for each phase and fecal score (FS) was measured daily. On day 7 postweaning, the challenged groups were orally inoculated with F18+E. coli (2.0 x 1010 CFU), the NC treatment received a sterile saline solution. On day 28, pigs were euthanized to collect jejunal samples to evaluate intestinal health and relative abundance (RA) of jejunal mucosa-associated microbiota. Data were analyzed using the MIXED procedure on SAS 9.4. The PC increased (P < 0.05) the RA of Prevotellaceae, Lachnospiraceae, and Ruminococcaceae when compared to NC. The HP reduced (P < 0.05) the RA of Veillonellaceae, Prevotellaceae, and Lachnospiraceae when compared to PC. The EP tended to reduce the RA of Streptococcaceae (P = 0.073) and Corynebacteriaceae (P = 0.074) when compared to PC. The PC increased (P < 0.05) occludin and tended to increase (P = 0.096) toll-like receptor-4 (TLR4) when compared to NC. The PC decreased (P < 0.05) average daily gain and average daily feed intake when compared to NC in days 7 to 28. The PC increased FS (P < 0.05) compared to the HP and EP days 7 to 11. The HP and EP decreased (P < 0.05) FS when compared to PC during days 7 to 11 and days 7 to 18. In conclusion, F18+E. coli challenge disrupted the jejunal mucosa-associated microbiota, increased TLR4 expression and FS, and consequently reduced GP. Both HP and EP phytobiotics supported intestinal morphology during the challenge to F18+E. coli by supporting enterocyte maturation. The HP and EP treatments exhibited antimicrobial-like effects by altering the jejunal mucosa-associated microbiota and reduced FS during the first 2 weeks post-challenge. The HP treatment showed potential antioxidant effects. Lay Summary Dietary and physiological stress makes the pigs susceptible to infections caused by enterotoxigenic Escherichia coli, one of the major reasons for postweaning diarrhea (PWD). PWD typically appears between the first and second weeks postweaning, causing watery diarrhea and potential mortality rates between 1.5% and 25%, reduced growth rates, and significant economic losses in pig production. Maintaining intestinal health is crucial for pig performance, as the intestine is essential for nutrient digestion and absorption and is the largest component of the animal's immune system. This study investigated how the inclusion of natural plant extracts (phytobiotics) from ground herbs and essential oils affected the intestinal health and growth of nursery pigs challenged with F18+E. coli. The results showed that both phytobiotics contributed to improved intestinal morphology. Both ground herb-based phytobiotics and essential oil-based phytobiotics exhibited antimicrobial properties reducing fecal score during the first 2 weeks post-challenge.