Effects of Paenibacillus spp. on broilers performance, intestinal, liver and pancreatic morphometrics, and pancreas enzymatic activity

Probiotics have shown improvement in the broilers performance and actuation on intestinal morphometrics. Thereby, this study was conducted to analyze these effects by adding three different levels of Paenibacillus ssp (PAE) in your feeds. A total of 400 d-old male Ross 308 chicks were placed in 20 floor pens with reused litter, and fed diet based on corn and soybean meal as basal diets that contained salinomycin. The treatments used were: basal diets without feed additives as a negative control, basal diets with growth promotant antibiotic (lincomycin) as a positive control, and diets containing 30, 45 and 60 ppm of PAE. The weight gain, feed intake and feed convertion were evaluated at starter phases (0-21d), grower phases (22-35d) and finisher phases (36-42d), and total phase. Mortality was recorded and the productivity index was calculated. At 14, 28 and 42 d, one chicken per pen was collected to evaluate villi length, density and width, and the goblet cells in the duodenum, jejunum and ileum, as well as the density of the liver Kupffer cells, cells and serous pancreatic acini. At 28 and 42 d-old pancreatic amylase, trypsin and chymotrypsin activities were evaluated. The data were analyzed in a completely randomized design with regression analyses of PAE levels and orthogonal contrasts with positive and negative controls. No significant effects (P>0,05) of inclusion levels of the PAE on weight gain, feed intake, feed convertion or productivity index were observed in all evaluated phases or in the whole grow out phase, except for a linear (P<0,05) improvement on the feed convertion in the finisher phase. No significant differences (P>0,05) were observed between probiotic levels in the negative and positive control groups. In gut morphometrics, no effects were detected on villi length. However, linearly, the PAE levels increased villi width at 14d and decreased at 28d, and villi density increased at 28 and 42d. The PAE levels had a quadratic effect on goblet cell numbers in all sections and age periods assessed. Amylase activity was the only pancreatic enzyme affected (P<0,05) by PAE levels at 28 and 42d. It was concluded that Paenobacillus spp. did not affect broiler performance; but it influenced gut morphometrics and pancreatic enzyme activity.