Poultry production aims to produce meat and eggs which are safe to be consumed by humans while also considering the health and welfare of the birds during production. Unfortunately, Salmonella-related infections in humans are largely blamed on contaminated animal products, including poultry meat and eggs. Enteric fever (including typhoid-and-paratyphoid fever) is potentially life-threatening and according to the WHO, an estimated 11-20 million people fall ill with enteric fever annually, where between 128 000 – 161 000 people die as a result (NICD South Africa, 2022). Enteric fever usually has no specific symptoms but includes diarrhoea and apathy. Even after humans and animals have recovered from enteric fever, they can still be either temporary or even chronic carriers, shedding the bacteria in their faeces.

Producers suffer major losses because of Salmonella infection in poultry. It not only leads to performance loss in birds but in the case of reportable strains, downgrading of broiler meat or even the termination of entire flocks may be implemented as control measures. Layer and breeder flocks may be terminated, or medicated (expensive and lengthy) while eggs are not allowed to enter the retail and hatching sectors. Salmonella Enteritidis (SE) and Glallinarum (SG) are controlled diseases according to the Animal Diseases Act (Act 35/1984).

Looking after your birds starts with the breeders. The breeders are the nucleus of poultry operations, and the health of broiler and layer chicks start long before the chick is hatched or a product is produced.  Ultimately health and productivity of our breeders will influence the viability and productivity of their progeny. Breeders transfer immunity and potential pathogens to chicks and also lay down nutrients in the eggs for the early development and growth of the chicks.

Bacterial threat in poultry

The selection for improved productivity leads to birds becoming increasingly at risk for bacterial infections. Birds have started to serve as major reservoirs for foodborne pathogens like Salmonella (Figure 1), usually residing as common groupings inside the gastrointestinal tract often without any noticeable symptoms in adult birds .

The basis for the control of Salmonella infection on poultry farms is good husbandry practices with high levels of hygiene. These control measures aim to prevent Salmonella from entering the farm via animals, feed, infected eggs, faecal matter,or the environment. Transmission can occur either horizontally (via faeces) or vertically (via egg from breeder). All-in/all-out operation systems play an important role in controlling the carry-over from one flock to another, together with effective pest control of rodents and wild birds. Even in the best farming environment, there won’t be zero risk. With an increase in the control of the use of medicine and antibiotics, it is crucial to find alternatives to ensure bird health and welfare in a safe and profitable food chain.

3 Ways to control Salmonella

1. Microbiota establishment – a crucial step for future flock health

Under current commercial conditions, the establishment of bacterial microflora of newly hatched chicks in clean and disinfected hatchers is highly dependent on environmental sources in the hatchery and on farm, in aerobic atmospheres (Figure 3).

• Fast microbiota establishment during the first hours of life, favouring the gut structure and immune development.
• Early and persistent improved protection against undesirable bacteria colonisation (Salmonella spp., E.coli, Clostridium).

2. Gut health support and food safety

The control of foodborne pathogens is a multi-factorial issue and concerns the entire production chain from farm to fork. To diversify the toolbox of preventative measures, the live yeast probiotic strain Saccharomyces cerevisiae var. bouldardii CNCMI-1079, brand name Levucell® SB, has been authorised by the European Union as the only probiotic feed additive for the reduction of carcass contamination by Salmonella spp. in broiler chickens through decreased levels of Salmonella in the faeces.

Levucell® SB acts on three lines of defence:

1. MICROBIOTA BALANCE – By consuming the oxygen inside the gut Levucell® SB creates a good environment for the development of beneficial bacteria. Levucell® SB interferes with the colonisation of undesirable bacteria because of its specific capacity to inhibit some activity of microbial toxins, such as Clostridium difficile Toxin A and E. coli endotoxin.
2. GUT INTEGRITY – Levucell® SB helps increase crypt depth and villus height. The positive effect on the regulation of tight junctions limits intestinal permeability.
3. NATURAL DEFENSES – Birds’ natural defences are reinforced thanks to local immune system modulation. Proper modulation of pro-and anti-inflammatory responses ensures an optimal stress response.

Why would we use a probiotic such as Levucell® SB?

Levucell® SB is a recognised and scientifically documented probiotic that helps to maintain a healthy gut and achieve optimal bird performance and welfare. Thanks to its unique properties supporting a balanced intestinal microbiota, Levucell® SB supplementation in broiler chickens has demonstrated its capacity to:

• reduce enteropathogen load in the gut and on carcasses;

reduce the effect on the performance of stress-inducing situations.Levucell® SB is the only probiotic authorised in the European Union for the reduction of Salmonella spp. contamination on carcasses of broilers.

3. Positive biofilm for safe animal production

What is biofilm?

• Biofilm is a structured community of microorganisms attached to a surface and enclosed in a self-produced polymer matrix (adapted from Costerton et al., 1999) (Figure 6).
• Biofilm can be formed by beneficial or undesirable bacteria.
• 90% of world microbial biomass is in biofilm form.

Positive biofilm

The idea is to apply beneficial bacteria that can form a positive biofilm along the farm surfaces just after disinfection but before the placement of new animals. The rapid establishment of a positive biofilm in the building cycle will leave less room for undesirable microorganisms to grow. LALFILM® PRO is a highly concentrated mix of live Bacillus spp. and lactic acid bacteria, specifically selected and formulated to create a protective biofilm in animal housing.

How is biofilm formed?

Selected biofilm forming bacteria Bacillus spp. and lactic acid bacteria are applied and form a protective positive biofilm on farm surfaces before recolonization by undesirable bacteria after cleaning and disinfection of housing (Figure 7).

Why is it important to apply a positive biofilm?

In poultry farms, several internal biosecurity measures are applied such as:

• Cleaning
• Disinfection
• Application of sanitary breaks.

Each of these steps impacts the level of infection pressure before new birds enter the barn. The implementation of a positive microbial biofilm in the barn before animal arrival and during the cycle is an added benefit on top of these procedures.

Conclusion

Salmonella spp. is one of the most difficult organisms to eradicate from poultry production systems. Food-borne diseases are commonly associated with Salmonella and the bacterium is regarded as one of the most important pathogens in public health. The control of Salmonella is not only important for public health but also for flock health, productivity and profitability. The poultry industry loses billions annually.

Vitam International can offer you the means of combatting Salmonella spp. affecting your bottom line with our 3-way approach (Figure 2) including AviGuard®, Levucell® SB and LALFILM® PRO as part of your management toolbox.