Intestinal Microbiota of Commercial Laying Hens in a Cage-Free System Fed with Probiotics

The cage-free rearing of laying hens combined with probiotics promotes intestinal health. The aim of this study was to evaluate the effect of adding probiotics on the intestinal microbiota of Isa Brown laying hens raised in a cage-free system. A total of 450 Isa Brown hens, 19 weeks old, were used in a cage-free system over three 28-day cycles in a completely randomized design with five treatments and six replicates, containing 15 birds per pen. The Isa Brown hens were fed a basal ration based on corn and soybean meal; a basal ration plus a single strain of <i>Bacillus subtilis</i> (500 g/t); a basal ration plus a single strain, <i>Bacillus subtilis</i> (1000 g/t); a basal ration plus a probiotic blend (<i>Bacillus subtilis</i>, <i>Enterococcus faecium</i>, <i>Lactobacillus acidophilus</i>, <i>Lactobacillus delbrueckii</i>, <i>Lactobacillus plantarum</i>, <i>Lactobacillus reuteri</i>, <i>Lactobacillus salivarius</i>, <i>Pediococcus acidilactici</i>) at a dosage of 200 g/t; and a basal ration plus the blend at 400 g/t. From one hen per replicate, contents from the small intestine, including the duodenum, jejunum, and ileum, were collected for DNA extraction and bacterial species identification. There was an increase in <i>Helicobacter brantae</i>, which was quantified at 86% in the diet containing 1000 g/t of the probiotic single strain of <i>Bacillus subtilis</i> and 87% in the diet containing 500 g/t dosage, in comparison to the basal ration. With the probiotic blend at 200 g/t, 37% <i>Lactobacillus crispatus</i> and 21% <i>Lactobacillus aviarius</i> were observed, while the dosage of 400 g/t of the probiotic blend increased the level of <i>Lactobacillus kitasatonis</i> to 68% compared to the basal ration. The inclusion of 200 g/t of the probiotic blend proved to be more beneficial to the small intestinal microbiota of laying hens.