Evaluation of yeast dietary supplementation in broilers challenged or not with Salmonella on growth performance, cecal microbiota composition and Salmonella in ceca, cloacae and carcass skin.

The dietary supplementation of Saccharomyces cerevisiae var. boulardii was evaluated in broilers challenged or not challenged with Salmonella Enteritidis (SE) using a 2 × 2 factorial arrangement. Depending on yeast inclusion at 0 (C) or 1 × 109 cfu/kg diet (Y) and SE challenge (0 or log 6.3 cfu/bird) on d 15, the experiment had four treatments C, Y, C-SE, and Y-SE, respectively. Each treatment had seven replicate floor pens with 15 broilers. Growth performance responses were determined weekly and overall for the 5 week experimental period. Salmonella levels and prevalence in ceca, cloacae, and carcass skin were determined by culture procedures, while cecal microbiota was determined by real time PCR. Yeast supplementation had no effect (PY > 0.05) on growth performance. For the overall post SE-challenge period (i.e., wk 3 to wk 5), Salmonella reduced body weight gain (BWG) (PSE < 0.001), feed intake (FI) (PSE = 0.032), and the European production efficiency (EPEF) factor (PSE = 0.005). Broilers Y-SE had higher (P < 0.001) overall BW gain compared to C-SE ones. Overall mortality was 2.14% and did not differ (P > 0.05) between treatments. Reduced Salmonella levels in the cloacae (P = 0.014) and on the breast skin (P = 0.006) and lower prevalence on the neck skin (P = 0.007) were noted for treatment Y-SE compared to C-SE. Yeast supplementation did not have an effect (P > 0.05) on cecal microbiota composition at d 1 and d 21 post SE-challenge. On the contrary, SE-challenge reduced cecal levels of total bacteria (PSE = 0.002), E. coli (PSE = 0.006), Bifidobacterium spp. (PSE = 0.006), Bacteroides spp. (PSE = 0.010), and Clostridial populations belonging to cluster I and cluster XIVa, (PSE = 0.047 and PSE = 0.001, respectively) on d 1 post SE-challenge. At 21 d post SE-challenge, only the levels of cecal Lactobacillus spp. (PSE = 0.001) and Bifidobacterium spp. (PSE = 0.049) were reduced compared to the non SE-challenged groups. In conclusion, yeast supplementation in SE challenged broilers (Y-SE) was beneficial for growth performance and reduced Salmonella presence compared to C-SE ones. The disturbance of cecal microbiota balance by SE merits further investigation for potential implications in gut and overall bird health.

Effects of dietary probiotic (Pediococcus acidilactici) supplementation on performance, nutrient digestibility, egg traits, egg yolk cholesterol, and fatty acid profile in laying hens.

The objective of this study was to determine the effect of dietary probiotic Pediococcus acidilactici (PA) strain MA18/5M on performance, egg traits, egg cholesterol content, and fatty acid composition in laying hens during a 24-wk period. A total of 222 Hy-Line Brown laying hens, 22 wk of age, were divided into 3 treatment groups. Control group (C) hens were fed a basal diet with no probiotic added. In group PA1, the basal diet was supplemented with PA at 100 mg.kg(-1) of feed for the first 12 wk and 50 mg.kg(-1) feed for the next 12 wk, whereas treatment PA2 was supplemented with 100 mg.kg(-1) feed for the whole trial period. Dietary treatments did not significantly affect the BW, feed intake, and egg production of hens. Pediococcus acidilactici supplementation increased egg weight (P < 0.05), eggshell thickness, eggshell relative weight, and egg specific gravity, and it improved feed efficiency ratio per kilogram of eggs (P < 0.01). Moreover, PA dietary supplementation resulted in a significant (P < 0.05) decrease in the number of broken eggs and eggs without the shell, leading to a significant (P < 0.01) reduction in the number of downgraded eggs (39% for PA1 and 52% for PA2). After 6 mo of probiotic supplementation, significant differences were also found in the fatty acid composition and cholesterol content of egg yolk. The yolk cholesterol content, regardless of PA dose, decreased by more than 10%. The concentrations of total polyunsaturated fatty acids, including linoleic acid and linolenic acid, were significantly higher in treatment PA2 (6.5% increase) than in C and PA1. In conclusion, dietary supplementation of Pediococcus acidilactici MA 18/5M at 100 mg.kg(-1) has potential commercial applications for improvements in hen performance and eggshell quality during the early laying period.