A rotary microtome machine (Leica RM 2155, Wetzlar, Germany) was used to cut each sample at 4 m and the sections were positioned on glass slides and heated at 57 C to dry. from 1 to 21 days, all the birds were fed the same basal diet. On day 22, the birds were weighed and randomly divided into six treatment groups and exposed to cyclic high temperature at 36 1 C for 3 h per day from 11:00 to 14:00 until the end of the experiment. From day 22 to 42 CP 465022 hydrochloride (finisher period), an equal number of birds were subjected to one of the following diets: NC (negative CP 465022 hydrochloride control) basal diet; PC (positive control) basal diet + 0.02% oxytetracycline; or AA (ascorbic acid) basal diet + 0.02% ascorbic acid. The other three groups (RI11, RS5 and UL4) were basal diet + 0.3% different postbiotics (produced from different strains, and defined as RI11, RS5 and UL4, respectively). The results demonstrated that birds fed RI11 diets had significantly higher final body weight, total weight gain and average daily gain than the birds that received the NC, PC and AA treatments. The feed conversion ratio was significantly higher in the RI11 group compared with CP 465022 hydrochloride the other groups. Carcass parameters were not affected by the postbiotic-supplemented diet. Postbiotic supplementation improved villi height significantly in the duodenum, jejunum and ileum compared to the NC, PC and AA treatments. The crypt depth of the duodenum and ileum was significantly higher in NC group compared to other treatment groups except RI11 in duodenum, and UL4 in ileum was not different with NC groups. The villus height to crypt depth ratio of duodenum and ileum was significantly higher for the postbiotic treatment groups and AA than the PC and NC treatment groups. The postbiotic RI11 group recorded significantly higher caecum total bacteria and count and lower count compared to the NC and PC treatment groups. The population in the NC group was significantly lower compared to the other treatment groups. CP 465022 hydrochloride The postbiotic (RI11, RS5 and UL4) and AA treatment groups showed lower Enterobacteriaceae and counts and caecal pH than the NC and PC treatment groups. The plasma immunoglobulin M CP 465022 hydrochloride (IgM) level was significantly higher in the birds receiving postbiotic RI11 than those receiving other treatments. The plasma immunoglobulin G (IgG) level was higher in the RI11 treatment group than in the NC, AA and RS5 groups. The plasma immunoglobulin A (IgA) level was not affected by postbiotic supplements. The hepatic GHR mRNA expression level was significantly increased in birds fed postbiotics RI11, RS5 and UL4, AA and PC compared to the NC-fed birds. Postbiotic RI11 led to significantly higher hepatic IGF-1 mRNA expression level compared to the NC, PC, and AA treatments. Mortality was numerically lesser in the postbiotic treatment groups, but not significantly different among all the treatments. In conclusion, among the postbiotics applied in the current study as compared with NC, PC and AA, RI11 could be used as a potential alternative antibiotic growth promoter and anti-stress treatment in the poultry industry. exhibit inhibitory action on various pathogenic bacteria, including and vancomycin-resistant Enterococci [34,35,36,37]. It has been demonstrated that the application of postbiotics as a feed additive in livestock promotes the growth performance and health of broilers [38,39,40], layers [41,42] and piglets [43,44], as well as enhancing rumen fermentation and health in ruminants [45,46]. In broilers under normal condition, postbiotic supplementation improves growth performance and health by promoting the immune status and gut health through the improvement of intestinal villus and increased lactic acid bacteria population and reduction of Enterobacteriaceae population and faecal pH [32,38,39,40,47]. In the context of postbiotics, apart from their ability to promote a healthy gut environment, the potential antioxidant capacity of postbiotics obtained from has been found to be particularly strong under heat-stress conditions. and particularly cultures have been shown to have high antioxidative activities [48,49]. However, there is scarce information on postbiotics as an antioxidant source, apart from their benefits in terms of health and growth performance. In heat-stressed broilers, probiotics Rabbit Polyclonal to ARMX3 have been shown to increase the hepatic antioxidant capacity [26,28,50] and postbiotics from are expected to provide similar benefits to those from probiotic bacteria. Despite the data showing the benefits of postbiotics in broilers under normal conditions, there is still a paucity of information on the effects of postbiotics under heat-stress conditions. This necessitates the elucidation of dietary postbiotics in broilers under heat-stress conditions, particularly on growth performance and.