Effects of Dietary Zinc and/or an Herbal Mixture on Intestinal Microbiota and Barrier Integrity in Lambs

The purpose of this experiment was to determine the impact of feed supplementation with organic zinc and/or a medicinal plants mixture on the composition and enzymatic activity of intestinal microflora as well as on the duodenal and jejunal barrier integrity in lambs. A total of 28 lambs were randomly allocated into 4 dietary treatments (n = 7) and were fed an unsupplemented basal diet (BD), or the BD enriched with organic Zn (Zn, 70 mg/kg diet), an herbal mixture (Herbmix, 100 g/day) or a combination of both additives (Zn+Herbmix). The Herbmix contained 33% each of Fumaria officinalis, Malva sylvestris, Matricaria chamomilla and 1% Artemisia absinthium. No significant effect on the fecal microbiota composition was observed due to the 35-day or 70-day dietary treatment. The intake of Zn alone resulted in decreased bacterial enzyme activities, such as β-glucuronidase, N-acetyl-glucosaminidase, β-galactosidase and β-glucosidase. The transepithelial electrical resistance of the small intestinal mucosa was not influenced by the dietary treatment, whereas simultaneous feeding of Zn and Herbmix exhibited higher claudin-1 and occludin levels in the jejunal mucosa. These results indicate that dietary intake of organic zinc and/or medicinal plants in the mentioned dosage did not alter the diversity of intestinal bacteria in growing lambs but did significantly influence bacterial enzyme activity. Supplementing the zinc and herbs combination showed the potential to regulate intestinal permeability by increasing the level of tight junction proteins in the jejunal mucosa.