Effect of dietary direct-fed microbial and yeast cell walls on cecal digesta microbiota of layer chicks inoculated with nalidixic acid resistant Salmonella Enteritidis

Abstract

Salmonella enterica serovar Enteritidis ( SE ) has consistently been the most common serotype associated with the foodborne Salmonellosis worldwide. In this study, the effect of a dietary direct-fed microbial ( DFM ) and yeast cell walls ( YCW ) under a challenge of nalidixic acid resistant SE strain using layer chicks has been investigated. A total of 160 newly hatched Dekalb White female chicks were randomly assigned into 2 experimental groups (80 birds/treatment), control group ( CON ) and treatment group ( DY ). Chicks were fed ad libitum a non–medicated-corn-soy based diet and DY was supplemented with the combination of DFM and YCW. At 8 days of age, 2.1 × 10 9 CFU/bird of the SE was given to all chicks by oral administration. On 3 days postinoculation ( dpi ), 20 chicks/group were euthanized and all cecal contents were collected for analysis. On 6, 10, and 14 dpi, the cecal contents were sampled from 16 chicks per group. The number of SE in the cecal contents was counted using culture-based methods. A 16S rRNA-based microbiota analysis was performed for additional microbial profiling. The CON and DY showed difference ( P ≤ 0.05) in β diversity throughout the trial. Prevalence of SE in cecal contents was lower ( P ≤ 0.05) in DY across all time-points. Lower abundance of Salmonella spp. was also shown in DY by liner discriminant analysis effect size ( LEfSe ). DY increased ( P ≤ 0.05) diversity of bacterial species in the cecal contents in DY at 10 and 14 dpi. For the SE challenged birds, SE reduction in DY was observed at 3 dpi and until the end of the trial at 14 dpi confirming a numerically larger difference between groups as well as an increase in bacterial species diversity in DY. It could be hypothesized that the SE reduction shown immediately after the challenge and the greater SE reduction shown after 10 dpi may be the synergistic effect of the combined feed additives.

Effect of a Bacillus subtilis plus Yeast Cell Wall Synbiotic on Salmonella Enteritidis Colonization in Ceca of Layer Pullets

“…In addition to the ileum and cloaca, cecal pouches are the preferred organs for SE colonization and establishment after it is ingested by chickens [35]. After an SE challenge, SE colonized the ceca of young layer pullets [21,26,29,30,36], layer pullets near sexual maturity [24,25,27,28], and adult laying hens [21][22][23]. In this study, orally infecting layer pullets with an SE dose of 6.3 × 10 7 CFU at 8 days of age resulted in colonization of the ceca, as evidenced by load and prevalence of SE in the ceca.…”

“…In addition, Bacillus-based probiotics and yeast cell wall-based prebiotics are among the most used feed additives in poultry. Only recently, however, has there been published research, though limited, testing the effects of combinations of Bacillus and MOS on SE colonization in layer birds [23,[28][29][30]. In these publications, the synbiotics tested contained different Bacillus probiotics and yeast cell wall prebiotics and used either young pullets or adult hens of either Hy-Line or Dekalb genetics background.…”

Effect of a Saccharomyces cerevisiae Postbiotic Feed Additive on Salmonella Enteritidis Colonization of Cecal and Ovarian Tissues in Directly Challenged and Horizontally Exposed Layer Pullets

“…Again, the authors reported no SE prevalence reduction in ceca, but in this case, reported significant mean log 10 MPN/g reductions for YCW and probiotic treatments alone, approximating adjusted means of 1.4 log 10 MPN/g, but only 0.78 log 10 MPN/g for the combined product group which was not significantly different from control [ 42 ]. The effects of a treatment containing a commercial YCW combined with a Bacillus subtilis probiotic administered to day-old layer chicks and directly challenged at 8 days with SE (2.1 × 10 9 CFU), resulted in mean cecal log 10 CFU/g reductions of 0.61, 0.49, 0.45, and 1.25 at 3, 6, 10, and 14 DPC, respectively [ 43 ].…”

Effects of Salmonella Enteritidis infection on TLRs gene expression and microbial diversity in cecum of laying hens

“…After challenged with SE, the abundance of the Firmicutes in the challenged group was higher than that of the control group, and the Bacteroidetes were significantly reduced. SE infection decreases the abundance of specific microbial genera and microbial diversity in the fecal material of laying hens and then causes dysbiosis [ 55 ]. Moreover, intestinal mucosal damage caused by SE infection leads to dysbiosis of the normal flora of the intestine, transforming intestinal flora from beneficial bacteria to pathogenic bacteria [ 56 ].…”