Tackle Salmonella Infections in Laying Hens with Silvafeed® Nutri P

Salmonella spp. are among major food-borne pathogens throughout the world, which cause approximately 94 million enteric infections and 155,000 human deaths each year (Majowicz et al., 2010). They are most often detected in poultry meat, although diseases are frequently associated with contaminated eggs and egg products (EFSA, 2015). Moreover, antimicrobial resistance in Salmonella species is a global threat for animal and public health. In Europe, multi-drug resistance in Salmonella species is a widespread threat for animal and public health, despite strict regulations for the use of antibiotics (EFSA, 2016). Therefore, alternative solutions to widely used antimicrobials are urgently needed. Commercial vaccines are readily available and effective for some serotypes even if they have several limitations (Varmuzova et al., 2016).

Silvafeed® Nutri P, produced by Silvateam, is a natural feed additive rich in tannins, which exhibits in vitro antimicrobial activity against various Salmonella serotypes such as SalmonellaEnteritidis, S.Typhimurium, S.Virchow and S.Gallinarum, as well as other bacterial pathogens (Tosi et al., 2007; Costabile et al., 2011). Moreover, the consumption of Silvafeed® tannins can result in the formation of a thin layer that protects the mucous membrane from “irritation” and reduces the absorption of toxic substances. Lower mucous irritation slows down the peristaltic movements, reducing the amount of fluid that is eliminated in the digestive tract and, therefore, preventing any risk of dehydration.

A field trial was carried out on laying hens to verify the antibacterial efficacy of Silvafeed® Nutri P on Salmonella Infantis, Virchow and Typhimurium strains (Figure 1).

The test subjects were battery cage raised laying hens, 2 flocks made of 25,000 hy-line white and 34,000 hy-line red brown. During the monitoring program for the control of Salmonella spp., the first flock was found infected with SalmonellaInfantis (isolated from faeces) and SalmonellaVirchow (isolated from eggs), while the second block of 34,000 hens with Salmonella Typhimurium (isolated from carcasses). In order to control these infections, Silvafeed® Nutri P was added to the feed for 18-20 days. During this period the faeces were periodically removed from all of the flocks to avoid further infections.

Figure 1: Evaluation of Silvafeed® Nutri P antibacterial activity against Salmonella spp. in layer hens.

During and after the treatment period with Silvafeed® Nutri P, the presence of SalmonellaInfantis, SalmonellaVirchow and Salmonella Typhimurium was regularly tested with bacteriological examinations of the carcasses, faeces and eggs.

At necroscopy, a pool of livers, spleens, ovaries and cecal tonsils was also taken from the carcasses for bacteriological examinations.

 

Figure 2: Field trial results at different production cycle stages.

After 20 days of treatment withSilvafeed® Nutri P, Salmonella Typhimurium and SalmonellaVirchow were not isolated either from carcasses, eggs or faeces. However, SalmonellaInfantis was isolated only in faeces (Figure 2).

All the samples taken afterwards were found negative for Salmonella spp. and this until the end of the production cycle.

These interesting results confirm that Silvafeed® Nutri P is a natural feed additive useful to reduce the faecal shedding of Salmonella spp. and, therefore, the environmental contamination. In fact, it has recently been suggested that contaminated faeces was the main route of egg contamination with S.Thyphimurium in laying hens (Pande et al., 2016). Silvafeed® Nutri P is a performing solution to control Salmonella spp. infections and prevent outbreaks, in combination with hygienic and other protective measures.

 

References

Costabile A., Sanghi S., Martín-Pelaez S., Mueller-Harvey I., Gibson G.R., Rastall R.A. and Klinder A., 2011. Inhibition of Salmonella Typhimurium by Tannins in Vitro. Journal of Food, Agriculture & Environment, 9 (1):119-124.

EFSA (European Food Safety Authority) and ECDC (European Centre for Disease Prevention and Control), 2015. The European Union Summary Report on Trends and Sources of Zoonoses, Zoonotic Agents and Food-borne Outbreaks in 2013. EFSA Journal, 13(1):3991.

EFSA (European Food Safety Authority) and ECDC (European Centre for Disease Prevention and Control), 2016. The European Union Summary Report on Antimicrobial Resistance in Zoonotic and Indicator Bacteria from Humans, Animals and Food in 2014. EFSA Journal, 14(2):4380.

Pande V.V., Devon R.L., Sharma P., Mc Whorter A.R. and Chousalkar K.K., 2016. Study of Salmonella Typhimurium Infection in Laying Hens. Frontiers in Microbiology, 7:203.

Tosi G., Graziani G., Denti R., 2007. In vitro antimicrobial activity of Silvafeed^® Nutri P on bacterial strains of poultry origin. Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna (Italy). Sponsored contract research.

Varmuzova K., Faldynova M., Elsheimer-Matulova M., Sebkova A., Polansky O., Havlickova H., Sisak F. and Rychlik I., 2016. Immune Protection of Chickens Conferred by a Vaccine Consisting of Attenuated Strains of Salmonella Enteritidis, Typhimurium and Infantis. Veterinary Research, 47:94.

Majowicz S.E., Musto J., Scallan E., Angulo F.J., Kirk M., O’Brien S.J., Jones T.F., Fazil A., and Hoekstra R.M., 2010. The Global Burden of Nontyphoidal Salmonella Gastroenteritis. Clinical Infectious Diseases, 50(6):882-889.