The objective of the present study was to investigate the potential effects associated with dietary probiotic inclusion and the stocking density on carcass traits, meat chemical composition, meat sensory quality, microbial populations and ileal histomorphology in broiler chickens raised under hot climate conditions. In total, 1800 1-day-old unsexed broiler chicks (Ross 308) were randomly allocated in a completely randomised design according to a 3 × 2 factorial arrangement, with three concentrations of a dietary probiotic (0, 200 and 400 mg/kg) containing 4 × 109 cfu/g of Bacillus subtilis and two stocking densities (12 or 18 birds/m2), forming six treatments, with three pens (replicates) each. The probiotic concentration had no significant (P > 0.05) effect on bodyweight gain, feed consumption, feed conversion ratio, carcass percentage and meat chemical composition. Dietary probiotic inclusion significantly (P = 0.02) increased the scores of meat colour and odour. The acceptability score was significantly (P < 0.03) affected by the stocking density. Dietary supplementation of the probiotic at both 200 and 400 mg/kg significantly (P = 0.05) reduced the counts of Escherichia coli and Salmonella in the gut and litter. In meat, dietary supplementation of the probiotic at 200 and 400 mg/kg significantly (P = 0.03) reduced the counts of E. coli, compared with those of the control group. Moreover, Salmonella was not detected in meat. Regarding the ileal villi and crypt morphology, dietary probiotic supplementation significantly (P = 0.05) increased the height of the villus. There were no significant probiotic concentration × stocking density interactions for any of the investigated parameters, except for the gizzard percentage. Thus, dietary probiotic supplementation in broilers raised under a high ambient temperature had a significantly positive effect on the ileal villus height and a significantly negative effect on the counts of E. coli and Salmonella in the gut and litter. No negative effects on growth performance, carcass parts and meat quality were detected.

Background and Aim: Mycoplasma infection in small ruminants is a serious problem in sheep and goat herds around the world. It is responsible for high economic losses and decreased animal productivity. This study aimed to highlight the clinical, histopathological, minimum inhibitory concentration (MIC), and molecular characterization of Mycoplasma species in sheep and goats in Menoufiya Governorate, Egypt. Materials and Methods: A total of 234 samples were collected; 104 samples were collected from pneumonic lung tissues from the abattoir, in addition, 10 and 20 samples collected from apparently and diseased sheep, respectively, and 40 and 60 samples were collected from apparently and diseased goats, respectively, which were subjected to isolation onto pleuropneumonia-like organism medium. Polymerase chain reaction (PCR), histopathological examination, and determination of the MIC were also performed. Results: Of 104 samples of lung tissues showing pneumonic lesions, 56 (53.84%) were positive for Mycoplasma isolation. The positive isolation of Mycoplasma from 10 and 20 samples from apparently and diseased sheep was 30% and 40%, respectively as well as the positive isolation of Mycoplasma was 17% and 56.66% out of 40 and 60 apparently healthy and diseased field goat's cases, respectively. All the diseased sheep and goats showed respiratory manifestations, including cough, bilateral nasal discharge, conjunctivitis, and systemic reaction. Evaluation of the MIC for Mycoplasma ovipneumoniae revealed that lincospectin and tylosin were the most effective antibiotics at 2.5 μg/mL. Histopathological examination of affected lung tissue showed extensive hemorrhagic pneumonia with extensive alveolar hemorrhage. The PCR technique proved to be a rapid, specific, and sensitive method for the detection of M. ovipneumoniae and Mycoplasma arginini at 390 and 326 bp, respectively. Conclusion: M. ovipneumoniae and M. arginini were the most prevalent species associated with respiratory infections in sheep and goats in the study area. Further studies are needed to investigate the role of these species in dissemination of the disease within herds of small ruminants.