Efficacy and safety assessment of microbiological feed additive for chicken broilers in tolerance studies

Probiotics as Alternatives to Antibiotics for the Prevention and Control of Necrotic Enteritis in Chickens

Necrotic enteritis (NE) in poultry is an economically important disease caused by Clostridium perfringens type A bacteria. A global trend on restricting the use of antibiotics as feed supplements in food animal production has caused a spike in the NE incidences in chickens, particularly in broiler populations. Amongst several non-antibiotic strategies for NE control tried so far, probiotics seem to offer promising avenues. The current review focuses on studies that have evaluated probiotic effects on C. perfringens growth and NE development. Several probiotic species, including Lactobacillus, Enterococcus, Bacillus, and Bacteroides bacteria as well as some yeast species have been tested in chickens against C. perfringens and NE development. These findings have shown to improve bird performance, reduce C. perfringens colonization and NE-associated pathology. The underlying probiotic mechanisms of NE control suggest that probiotics can help maintain a healthy gut microbial balance by modifying its composition, improve mucosal integrity by upregulating expression of tight-junction proteins, and modulate immune responses by downregulating expression of inflammatory cytokines. Collectively, these studies indicate that probiotics can offer a promising platform for NE control and that more investigations are needed to study whether these experimental probiotics can effectively prevent NE in commercial poultry operational settings.

Phytogenic Ingredients from Hops and Organic Acids Improve Selected Indices of Welfare, Health Status Markers, and Bacteria Composition in the Caeca of Broiler Chickens

Simple Summary

The selection for the rapid growth rate in broiler chickens that has been carried out over the years has negatively influenced their health and welfare status. In recent years, a number of reports have been delivered on the use of additives that improve broilers’ intestinal peristalsis and production results. The authors of this paper have proved that applying a mixture with 50% hops (manifesting strong antioxidant, antibacterial, and antifungal properties) may bring benefits to the quantity and quality of the final product. This may refer to the production performance, flock health status, and welfare of birds. The thematic scope of this research is currently of significant importance, as veterinary inspections pay particular attention to the quality of litter and the welfare of birds, and this motivates producers to improve breeding conditions, which will contribute to better production systems.

Abstract

The objective of this study was to determine the influence of phytogenic product-supplemented, organic acid-supplemented, and prebiotic-supplemented diets on the production results, antioxidative status, and selected welfare indices in broiler chickens. A total of 1155 one-day old male Ross 308 broilers were randomly assigned to one of three treatment groups: Group C, no additives; Group A, supplemented with phytogenic supplement (50% hop); and Group P, supplemented with 65% organic acids and their salts, and 30% prebiotic complex. Health condition and production results were monitored during the entire experiment. After 42 days, 10 birds from each dietary treatment group were selected for blood sampling and slaughter analysis. The results obtained revealed that over the whole feeding period, none of the investigated additives significantly affected broiler performance indices. However, feeding the birds treatment-A increased the relative abundance of Bifidobacterium in caecal digesta compared to the other treatments, whereas feeding treatment-P increased the relative abundance of Lactobacillus compared to the control treatment. Overall, treatment-A was more effective at increasing relative abundance of Clostridia in birds at 42 days of age than treatment-P. Finally, there were no changes in blood levels of antioxidant indices or liver function indicators.

Cytotoxicity in Vero cells and cytokines analyses in Balb/c mice as safety assessments of the probiotic mixture Saccharomyces cerevisiae RC016 and Lactobacillus rhamnosus RC007 for use as a feed additive

The objective was to carry out cytotoxicity assays in Vero cells and cytokines analyses in Balb/c mice as safety assessments to evaluate the probiotic mixture (M) Saccharomyces cerevisiae RC016 (Sc) and Lactobacillus rhamnosus RC007 (Lr) for use as feed additive. Vero cells (10⁴ cells per well) were exposed to Sc (2·08 × 10⁷ , 2·08 × 10⁶ ; 2·08 × 10⁵ cells per ml), Lr (8·33 × 10⁷ ; 8·33 × 10⁶ ; 8·33 × 10⁵ cells per ml) and their M (1 : 1). Sc concentrations did not affect the Vero cells viability; in contrast, they were lower when exposed to Lr (P ˂ 0·0001). Vero cells showed increasing viability with M decreasing concentrations (91% viability with M2). Control BALB/c mice received only phosphate buffer saline and the others received the M. The IL-10, IL-6 and TNFα concentrations from intestinal fluid were analysed and no significant differences were observed among treatments. The same occurred with the ratio between IL-10/TNF-α. Beneficial effects of probiotics are associated with the regulation of the excessive inflammatory response; it is desirable they can modulate the cytokines production only under pathological conditions. Here, M administration to healthy mice did not induce negative side effects and expands the knowledge about beneficial effects of using probiotic microorganisms in mixture for feed additives development.

Examination of the Expression of Immunity Genes and Bacterial Profiles in the Caecum of Growing Chickens Infected with Salmonella Enteritidis and Fed a Phytobiotic

Simple Summary

Salmonellosis is among the most common infectious poultry diseases that also represent a high risk to human health. The pathological process caused by Salmonella enterica serovar Enteritidis (SE) triggers in the caecum the expression of certain genes, e.g., avian β-defensins (gallinacins), cytokines (interleukins), etc. On the other hand, gut microbiota influences the infection potential of pathogens. The present study aimed at revealing the differential expression of genes associated with the immune system and changes in the bacterial communities in the intestine of growing chickens in response to SE infection. We also tested a feed additive, essential oils-based phytobiotic Intebio, as a potential alternative to antibiotics and showed effects of its administration on the caecal microbiome composition and the expression of some genes related to immunity. The phytobiotic showed its efficiency for application in poultry rearing and production.

Abstract

This study was performed to investigate the differential expression of eight immunity genes and the bacterial profiles in the caecum of growing chickens challenged with Salmonella enterica serovar Enteritidis (SE) at 1 and 23 days post inoculation (dpi) in response to SE infection at 19 days of age and administration of the phytobiotic Intebio. Following infection, the genes CASP6 and IRF7 were upregulated by greater than twofold. Chicks fed Intebio showed at 1 dpi upregulation of AvBD10, IL6, IL8L2, CASP6 and IRF7. At 23 dpi, expression of AvBD11, IL6, IL8L2, CASP6 and IRF7 lowered in the experiment subgroups as compared with the control. Examination of the caecal contents at 1 dpi demonstrated a significant decrease in the microbial biodiversity in the infected subgroup fed normal diet. Bacterial content of Lactobacillus and Bacillus declined, while that of Enterobacteriaceae rose. In the infected subgroup fed Intebio, a pronounced change in composition of the microflora was not observed. In the early infection stages, the phytobiotic seemed to promote response to infection. Subsequently, an earlier suppression of the inflammatory reaction took place in chickens fed Intebio. Thus, use of Intebio as a drug with phytobiotic activity in chickens, including those infected with Salmonella, proved to be promising.