Probiotics in Poultry Nutrition as a Natural Alternative for Antibiotics

Since the early 1950s, antibiotics have been used in poultry for improving feed efficiency and growth performance. Nevertheless, various side effects have appeared, such as antibiotic resistance, antibiotic residues in eggs and meat, and imbalance of beneficial intestinal bacteria. Consequently, it is essential to find other alternatives that include probiotics that improve poultry production. Probiotics are live microorganisms administered in adequate doses and improve host health. Probiotics are available to be used as feed additives, increasing the availability of the nutrients for enhanced growth by digesting the feed properly. Immunity and meat and egg quality can be improved by supplementation of probiotics in poultry feed. Furthermore, the major reason for using probiotics as feed additives is that they can compete with various infectious diseases causing pathogens in poultry's gastrointestinal tract. Hence, this chapter focuses on the types and mechanisms of action of probiotics and their benefits, by feed supplementation, for poultry health and production.

Systematic review of products with potential application for use in the control of Campylobacter spp. in organic and free-range broilers

Campylobacter spp. are some of the most important food-borne zoonoses in Europe and broiler meat is considered the main source of Campylobacter infections. Organic and free-range broilers have access to outdoor reservoirs of Campylobacter and are more frequently infected at slaughter than the conventional broiler flocks. Limitations to biosecurity and treatment options in these production types calls for additional solutions. This review examines intervention methods with sufficient strength and quality, which are able to reduce the load of Campylobacter safely and efficiently and discuss their applicability in organic and free-range broiler production. Four different products passed the inclusion criteria and their quality examined: ferric tyrosine chelate, a prebiotic fermentation product of Saccharomyces cerevisiae, short-chain fatty acid butyrate coated on microbeads added to feed, and a mix of organic acids added to the drinking water. Though potential candidates for reducing Campylobacter in broilers were identified, there is a lack of large scale intervention studies that demonstrate an effect under field conditions of a free-range broiler production.

Medicinal Plants for Prophylaxis and Therapy of Common Infectious Diseases In Poultry-A Systematic Review of In Vivo Studies

Medicinal plants for prophylaxis and therapy of common infectious diseases in poultry have been studied for several years. The goal of this review was to systematically identify plant species and evaluate their potential in prophylaxis and therapy of common diseases in poultry caused by bacteria and gastrointestinal protozoa. The procedure followed the recommendations of the PRISMA statement and the AMSTAR measurement tool. The PICOS scheme was used to design the research questions. Two databases were consulted, and publications were manually selected, according to predefined in- and exclusion criteria. A scoring system was established to evaluate the remaining publications. Initially, 4197 identified publications were found, and 77 publications remained after manual sorting, including 38 publications with 70 experiments on bacterial infections and 39 publications with 78 experiments on gastrointestinal protozoa. In total, 83 plant species from 42 families were identified. Asteraceae and Lamiaceae were the most frequently found families with Artemisia annua being the most frequently found plant, followed by Origanum vulgare. As compared to placebo and positive or negative control groups, antimicrobial effects were found in 46 experiments, prebiotic effects in 19 experiments, and antiprotozoal effects in 47 experiments. In summary, a total of 274 positive effects predominated over 241 zero effects and 37 negative effects. Data indicate that O. vulgare, Coriandrum sativum, A. annua, and Bidens pilosa are promising plant species for prophylaxis and therapy of bacterial and protozoal diseases in poultry.

Nanoliposome-Encapsulated and Non-Encapsulated Phenolics From Achillea millefolium and Their Biological Function in Mice Challenged by Campylobacter jejuni: A Comparative Study

The objective of this research was to develop the nanoliposome-encapsulated phenolic rich fraction from Achillea millefolium (A. millefolium) and to investigate its antibacterial and health-promoting activities in mice challenged by pathogenic foodborne Campylobacter jejuni. The A. millefolium was extracted and the ethyl acetate fraction was found to be the phenolic-rich fraction (PRF) containing 14.72 ± 2.39 mg gallic acid equivalent (GAE)/g dry weight (DM). Base on the results, the synthesized nanoliposome-loaded PRF (PRF-NLs) with the size of 187.2 nm exhibited homogeneous dispersion (PDI 0.213) and moderate stability behavior in colloidal dispersions (Zeta potential −37.45). The non-encapsulated PRF and PRF-NLs were gavaged orally in the mice for 28 days, and mice were challenged with C. jejuni on day 21. The results indicated that the dietary supplementation of non-encapsulated PRF and PRF-NLs significantly (p < 0.05) improved the average daily weight gain, food intake, liver function, antioxidant status, and morphostructural characteristics of the ileum. However, the PRF-NLs appeared to be more potent as compared to non-encapsulated PRF. The higher biological activity of PRF-NLs could be associated with the higher intestinal solubility and absorption of nanoliposome-encapsulated PRF. Thereby, the nanoliposome-encapsulated PRF could be considered as a natural antibiotic alternative called phytobiotic to prevent intestinal infection caused by enteropathogenic C. jejuni.

Preventive antimicrobial action and tissue architecture ameliorations of Bacillus subtilis in challenged broilers

Background and Aim:

Probiotics improve intestinal balance through bacterial antagonism and competitive exclusion. This study aimed to investigate the in vitro antimicrobial activity, as well as the in vivo preventive, immunological, productive, and histopathological modifications produced by probiotic Bacillus subtilis.

Materials and Methods:

The in vitro antimicrobial activities of B. subtilis (5×10⁶ CFU/g; 0.5, 1.0*, 1.5, and 2.0 g/L) were tested against Escherichia coli O157: H7, Salmonella Typhimurium, Candida albicans, and Trichophyton mentagrophytes after exposure times of 0.25, 0.5, 1, and 2 h using minimal inhibitory concentration procedures. A total of 320 1-day-old female Ross broiler chickens were divided into five groups. Four out of the five groups were supplemented with 0.5, 1.0*, 1.5, and 2.0 g/L probiotic B. subtilis from the age of 1 day old. Supplemented 14-day-old broiler chickens were challenged with only E. coli O157: H7 (4.5×10¹² CFU/mL) and S. Typhimurium (1.2×10⁷ CFU/mL). A total of 2461 samples (256 microbial-probiotic mixtures, 315 sera, 315 duodenal swabs, and 1575 organs) were collected.

Results:

The in vitro results revealed highly significant (p<0.001) killing rates at all-time points in 2.0 g/L B. subtilis: 99.9%, 90.0%, 95.6%, and 98.8% against E. coli, S. Typhimurium, C. albicans, and T. mentagrophytes, respectively. Broilers supplemented with 1.5 and 2.0 g/L B. subtilis revealed highly significant increases (p<0.01) in body weights, weight gains, carcass weights, edible organs’ weights, immune organs’ weights, biochemical profile, and immunoglobulin concentrations, as well as highly significant declines (p<0.01) in total bacterial, Enterobacteriaceae, and Salmonella counts. Histopathological photomicrographs revealed pronounced improvements and near-normal pictures of the livers and hearts of broilers with lymphoid hyperplasia in the bursa of Fabricius, thymus, and spleen after supplementation with 2.0 g/L B. subtilis.

Conclusion:

The studies revealed that 1.5-2.0 g of probiotic B. subtilis at a concentration of 5×10⁶ CFU/g/L water was able to improve performance, enhance immunity, and tissue architecture, and produce direct antimicrobial actions.

Live Bacterial Prophylactics in Modern Poultry

Commercial poultry farms frequently use live bacterial prophylactics like vaccines and probiotics to prevent bacterial infections. Due to the emergence of antibiotic-resistant bacteria in poultry animals, a closer examination into the health benefits and limitations of commercial, live prophylactics as an alternative to antibiotics is urgently needed. In this review, we summarize the peer-reviewed literature of several commercial live bacterial vaccines and probiotics. Per our estimation, there is a paucity of peer-reviewed published research regarding these products, making repeatability, product-comparison, and understanding biological mechanisms difficult. Furthermore, we briefly-outline significant issues such as probiotic-label accuracy, lack of commercially available live bacterial vaccines for major poultry-related bacteria such as Campylobacter and Clostridium perfringens, as well research gaps (i.e., probiotic-mediated vaccine adjuvancy, gut-brain-microbiota axis). Increased emphasis on these areas would open several avenues for research, ranging from improving protection against bacterial pathogens to using these prophylactics to modulate animal behavior.