In-vitro selection of lactic acid bacteria to combat Salmonella enterica and Campylobacter jejuni in broiler chickens.

Campylobacter and Salmonella are the two most prominent foodborne zoonotic pathogens reported in the European Union. As poultry is one of the major sources of these pathogens, it is imperative to mitigate the colonization of these pathogens in poultry. Many strains of lactic acid bacteria (LAB) have demonstrated anti-Salmonella and anti-Campylobacter characteristics to varying degrees and spectrums which are attributed to the production of various metabolites. However, the production of these compounds and consequent antimicrobial properties are highly strain dependent. Therefore, the current study was performed to select a potent LAB and determine its causal attribute in inhibiting Salmonella enterica and Campylobacter jejuni, in-vitro. Six LAB (Lactiplantibacillus plantarum (LP), Lacticaseibacillus casei (LC), Limosilactobacillus reuteri (LR), Lacticaseibacillus rhamnosus (LRh), Leuconostoc mesenteroides (LM) and Pediococcus pentosaceus (PP)) and three serovars of Salmonella enterica (Typhimurium, Enterica and Braenderup) and Campylobacter jejuni were used in the current study. Spot overlays, well diffusion, co-culture and co-aggregation assays against Salmonella and well diffusion assays against Campylobacter jejuni were performed. Organic acid profiling of culture supernatants was performed using HPLC. The results indicated that LRh, LM and PP had the most significant anti-Salmonella effects while LP, LC, LM and PP displayed the most significant anti-Campylobacter effects. Lactic acid and formic acid detected in the culture supernatants seem the most likely source of the anti-Salmonella and anti-Campylobacter effects exhibited by these LAB. In conclusion, Leuconostoc mesenteroides displayed the most significant overall anti-pathogenic effects when compared to the other LAB strains studied, indicating its potential application in-vivo.

Prophybiotics for in-ovo stimulation; validation of effects on gut health and production of broiler chickens.

Probiotics and phytobiotics have demonstrated effective improvement of gut health in broiler chickens when individually administered in-ovo. However, their combined use in-ovo, has not been studied to date. We coined the term "prophybiotic" (probiotic + phytobiotic) for such a combination. The current study therefore, aimed to elucidate the effects of combined use of a selected probiotic and a phytobiotic in-ovo, on broiler gut health and production parameters, as opposed to use of probiotics alone. ROSS 308 hatching eggs were injected with either Leuconostoc mesenteroides (probiotic: PB) or L. mesenteroides with garlic aqueous extract (prophyiotic: PPB) on the 12th day of incubation. Relative abundances of bacteria in feces and cecal content (qPCR), immune related gene expression in cecal mucosa (qPCR) and histomorphology of cecal tissue (PAS staining) were analyzed along with production parameters (hatch quality, body weight, feed efficiency and slaughter and meat quality). PPB treatment increased the abundance of faecalibacteria and bifidobacteria in feces (d 7) and Akkermansia sp. in cecal content. Moreover, it decreased Escherichia coli abundance in both feces (d 34) and cecal content. PB treatment only increased the faecalibacteria in feces (d 7) and Akkermansia sp. in the cecal content. Moreover, PPB treatment resulted in up-regulation of immune related genes (Avian beta defensing 1, Free fatty acid receptor 2 and Mucin 6) and increased the crypt depth in ceca whereas PB treatment demonstrated a higher crypt depth and a tendency to increase Mucin 6 gene expression. Both treatments did not impair the production parameters studied. In conclusion, our results suggest that in-ovo PPB treatment may have enhanced potential in boosting the immune system without compromising broiler production and efficiency, as compared to the use of probiotic alone. Our study, highlights the potential of carefully selected PPB combinations for better results in improving gut health of broiler chickens.

In-vitro screening of compatible synbiotics and (introducing) "prophybiotics" as a tool to improve gut health.

Synbiotics have been intensively studied recently to improve gut health of humans and animals. The success of synergistic synbiotics depends on the compatibility of the prebiotic and probiotic components. Certain plant extracts possess both antimicrobial and prebiotic properties representing a potential use in combination with probiotics to improve the gut health. Here, we coined the term "prophybiotics" to describe this combined bioactivity. The current study aimed to select prebiotics that are preferred as an energy source and antimicrobial plant extracts which do not inhibit the growth, of six strains of lactic acid bacteria (LAB namely; Lactiplantibacillus plantarum, Lacticaseibacillus casei, Limosilactobacillus reuteri, Lacticaseibacillus rhamnosus, Leuconostoc mesenteroides, and Pediococcus pentosaceus) in-vitro to identify compatible combinations for potential synbiotic/prophybiotic use, respectively. Their growth kinetics were profiled in the presence of prebiotics: Inulin, Raffinose, and Saccharicterpenin with glucose, as the control, using carbohydrate free MRS broth media. Similarly, their growth kinetics in MRS broth supplemented with turmeric, green tea, and garlic extracts at varying concentrations were profiled. The results revealed the most compatible pairs of prebiotics and LAB. Turmeric and garlic had very little inhibitory effect on the growth of the LAB while green tea inhibited the growth of all LAB in a dose-dependent manner. Therefore, we conclude that turmeric and garlic have broad potential for use in prophybiotics, while the prebiotics studied here have limited use in synbiotics, with these LAB.