Salmonella

Selected Species

OUR AMBITION

Treatment and prevention of Salmonella in poultry

Salmonella is an enteric pathogen that can infect almost all animals including humans. Salmonellosis in poultry is caused by Gram-negative bacteria from the genus Salmonella. There are only two species in this genus, enterica and bongori (Lin-Hui and Cheng-Hsun, 2007), but almost 2,700 serotypes (serovars), of which around 10% have been isolated from birds.  

In general, most serotypes of Salmonella can infect several animal species (Gast, 2008), such as Salmonella Typhimurium and Salmonella Enteritidis

Food safety and Salmonella in poultry

Poultry meat and eggs are the most common sources of Salmonella infections (Salmonellosis) in humans. Salmonellosis is one of the most difficult diseases to control in poultry flocks. As most animal species can be infected with Salmonella, cross-infection is very common among birds.  Moreover, birds can be infected with Salmonella without showing any signs of the disease. 

Feed additives can combat the occurrence of Salmonella in poultry by supporting gut health and immune function.

Prevalence of Salmonella in commercial poultry

The most common serotypes of Salmonella in commercial chickens, turkey and ducks worldwide are:

  • - S. Gallinarum 
  • - S. Typhimurium 
  • - S. Enteritidis 
  • - S. Heidelberg  
  • - S. Montevideo
  • - S. Infantis  
  • - S. Mbandaka  
  • - S. Kentucky  
  • - S. Javiana  
  • - S. Newport 

In 2018, the European Union reported data on Salmonella outbreaks in broilers and layers during 2016. Salmonella Infantis was the most reported serovar in broiler flocks, and Salmonella Enteritidis in laying flocks (EFSA 2016).

The prevalence can vary among countries and between regions of the same country. 

Figure 1. Breakdown of Salmonella serovars in broilers flocks, EU MSs, 2016 (N = 1,707) | Source: EFSA 2016

Figure 2. Breakdown of Salmonella serovars in laying hen flocks, EU MSs, 2016 (N = 1,194) | Source: EFSA 2016

Complexity and control

In addition to the large number of serotypes, the genus Salmonella presents a large variability among the serotypes. Some are more adapted to the intestine and do not go beyond the gut, others can get into the blood stream and have the ability to colonize liver and spleen. Some survive longer in the environment, others do not. Most of the animal species can be infected with Salmonella, therefore cross infection is very common among birds.  

These and other general features of Salmonella make its control difficult. It requires a lot of knowledge and investments. We have to establish a program and not just a single procedure. Salmonellosis is not the most devastating poultry disease, but it is one of the most difficult diseases (agent) to control. The main reason is the large variety of serotypes and the very complex epidemiology of this microorganism. 

To explore alternatives to control Salmonella in poultry, we have to divide them into two groups: Typhoid and Paratyphoids. 

Group Serotypes

Typhoid group 

Salmonella gallinarum 
Salmonella pullorum 

Paratyphoid group 

All other serotypes 

Table 3Salmonella groups and serotypes

The typhoid group includes two members: Salmonella gallinarum and Salmonella pullorum. The paratyphoid group contains all other serotypes of Salmonella.  

For the control of typhoid infection in poultry we have to focus on good biosecurity, all-in-all out management of the flock and eventually the use of vaccine (if available). In case of outbreaks, the eradication procedure is costly, but at the end it is more efficient and results in better economics. When done properly and associated with biosecurity, it works very well. Nowadays, in a global market, raising birds free of typhoid Salmonella is essential for broiler producers that want to remain competitive.  

The difficulties for the control of paratyphoid Salmonella are greater. There is no single procedure that guarantees a positive flock to become negative. Also, a negative flock can become infected due to a variety of contamination vectors. Rigorous biosecurity can minimize the chances for Salmonella, but cannot guarantee absolute control. It is important to remember that not all Salmonella are the same: some respond to a certain product or treatment strategy better than others. We must be aware of which one is working better with the serotype that we are dealing with in order to get the best results.  

Typhoid group: Salmonella gallinarum and Salmonella pullorum

This group is represented by only two serotypes. Salmonella gallinarum and Salmonella pullorum, the causative agents of fowl typhoid and Pullorum disease, respectively, are specific to poultry and found mainly in chickens and turkeys.  

Among the 2,700 serotypes, only these two can cause a high mortality rate in birds. They can be transmitted both horizontally within a flock and vertically from generation to generation. Once the flock is infected the survivors will remain carriers forever (Shivaprasad and Barrow, 2008). Because of these characteristics, the commercial poultry meat industry worldwide uses eradication as a standard control procedure.  

A company or a producer that has positive breeders or broiler flocks will have a hard time competing economically with other companies or producers that are free of typhoid Salmonella. Considering that, in case of an outbreak, eradication becomes the rule. The use of antibiotics can be a strategy to reduce mortality in breeders, layers and broilers, but the flock remains positive and becomes a source of infection for other flocks. It is important to consider that the eradication procedure works well to control outbreaks of Salmonella gallinarum/Salmonella pullorum, but needs to be followed by good biosecurity procedures.

Combating Salmonella in poultry

Organic acids have a direct antimicrobial activity against pathogens such as Salmonella. They may also contribute to gut health indirectly by improving digestibility. This means that less non-digested feed reaches the lower part of the intestine where it might feed opportunistic bacteria, encouraging the proliferation of pathogens.

Biotronic® Top3 is a feed additive that has been formulated to control Gram-negative bacteria in poultry production systems (bacteria that cause infections including pneumonia, bloodstream infections, wound infections, and meningitis).

Biotronic® Top3 is a powdered product whose active ingredients are released sequentially, starting in the feed and then throughout the gastrointestinal tract, so as to deliver maximum results. It includes organic acids, cinnamaldehyde, and BIOMIN® Permeabilizing Complex™.   Adding Biotronic® Top3 to broiler diets reduces the total number of Salmonella while creating a favorable environment for the proliferation of beneficial bacteria. It can be added directly into compound feed and has no negative side effects and no withdrawal times.

Biosecurity and sources of contamination

Because Salmonella gallinarum/Salmonella pullorum are found mainly in chickens and turkeys, avoiding contact with these birds outside of the farm is the key to prevention.

Good biosecurity is key in preventing the infection from getting into the farms. In our experience, humans as carriers are the main source of typhoid infection, and backyard chickens are the most important reservoir of these bacteria. Most of the time, employees are the ones that have contact with an infected chicken and then introduce the infection into a clean flock. A comprehensive biosecurity program will cover all potential sources of poultry farm contamination.

Figure 4. Sources of poultry farm contamination | Source: BIOMIN

Vaccination

A vaccine called 9R, used for typhoid infection, is available worldwide. It is a rough strain of Salmonella Gallinarum (Shivaprasad and Barrow, 2008), but in most countries, it is not allowed in broilers, because it interferes in the serology monitoring of chicken meat. If used, it will protect against both Salmonella gallinarum and Salmonella pullorum.

Salmonella gallinarum in egg production

In case of layer chickens (eggs), the frequency of typhoid infection, mainly caused by Salmonella gallinarum, is a lot higher worldwide when compared to that of broiler flocks. The main reason is the lack of good biosecurity. Most of the layer farms have multiple ages, which do not allow all-in all-out management, compromising biosecurity.  

Once the infection is installed, it becomes impossible to eradicate, unless the whole farm is cleaned. For that reason, most of the layer flocks are vaccinates with 9R. The vaccine avoids high mortality and reduces the egg production, but the infection can still occur.

Parathyphoid group

This group is represented by all other serotypes of Salmonella except for the two in the typhoid group. As a general rule, paratyphoid types do not cause mortality in poultry and do not interfere with performance.  

The main reason to establish a control program is to reduce or avoid human infection by consuming contaminated meat and eggs. The control strategies are a lot more complex than for the typhoid group.  

The main factors that add complexity in Salmonella typhoid control strategies:  

  • a variety of animals including mammals can be a source of cross-infection in birds 
  • the bacteria are widespread in nature and able to survive weeks or months  
  • Once a flock is infected the amount of Salmonella can be reduced but not completely eliminated 
  • A single flock can be infected with more than one serotype  
  • Limited benefit of vaccine use because there is minimal or no protection among different serotypes (vaccine for S. enteritidis does not protect against S. typhimurium
  • Treatment with antibiotics can reduce the number of excreted bacteria but does not eliminate them completely 
  • Infected birds are asymptomatic and they do not present signs of the disease 

As a result, effective control cannot be based on one or two procedures. Rather, the whole chain must be involved: breeders, hatchery, grow-out, feed and processing plant. It is important to point out that the port of entry for paratyphoid Salmonella in a broiler flock is the same for breeders.

Salmonella control program

Therefore, the challenge in establishing a Salmonella control program is to consider its very complex epidemiology and the entire production chain involved.  

Setting up a monitoring program and serotyping the isolates are essential to any control program. Once we know which serotype is circulating and where the source is, then we can set up a control program. 

The program has to start with the knowledge of the final product, generally at the processing plant. If Salmonella is present, its serotype needs to be identified. Once the serotype is known, we have to go back to the chain (breeders, hatchery, grow-out and feed), get the isolates and serotype them to find the source.  

If the same serotype is found in the breeders, then our focus for control should be in the breeders. If we do not find Salmonella in the day-old chick, but instead find it in the feed, our emphasis for the control should be in the feed and not in the breeders.  

Sometimes we can identify more than one source of infection; in this case all of them need to be considered for the control program. The main sources of infection and products/procedures available for the control program in the chain of poultry production are shown below. 

Breeders and paratyphoid Salmonella control

In case breeders are positive for paratyphoid Salmonella, it is important to identify the source of infection: from the grandparents or acquired on the farm. Once infected, birds will remain infected, and in this case, the work has to be done at the growth promoter (GP) levels. If the infection was acquired on farm, then we have to reinforce biosecurity, rodent control, cleaning and disinfection, downtime, other animal contact, visitors, repair crew and vaccination team. Any equipment introduced into the farm has the potential of carrying Salmonella. In special circumstances, vaccines can be used in breeders. Probiotics can be used during the first days or after the medication/stress periods. Products in the feed can also be used (see feed mill section).

Feed mills and paratyphoid Salmonella control

Feed can be an important source of infection for paratyphoid Salmonella (less so for Typhoid Salmonella). The feed mill environment, feed ingredients and the delivered feed must be monitored for Salmonella, because they are a potential source (Jones, 2011). The feed pelletizing process destroys Salmonella, but contamination can occur during cooling and transportation of the feed.  

Animal by-products are common sources of Salmonella in a feed mill, they also have to be monitored and treated if necessary. Soybean can also be a source of infection, corn in a lesser degree.

The feed can be used to deliver products against Salmonella for breeders, broilers and layers such as: antimicrobials, probiotics, organic acids, MOS, essential oils and others. Not all products are the same, but most of them can make a contribution in reducing Salmonella infection and should be used accordingly. 

Figure 5. Animal by-products, soy and corn can be vectors for Salmonella in feed

Hatchery and Salmonella control

Proper management, cleaning and disinfection of the hatchery all contribute to limiting the incidence and spread of Salmonella. Cross contamination can occur, mainly when there is a mixture of birds from positive and negative flocks.  

If we keep eggs from a positive flock, incubate and hatch them separately, most of the time they will not contaminate chicks from negative flocks. For typhoid Salmonella, chicks hatched from a positive breeder flock will be positive. Therefore, a well-managed hatchery can avoid cross contamination, but will not eliminate Salmonella from a positive flock. Probiotics, antimicrobials and eventually vaccines can be delivered in the hatchery and help with overall Salmonella control. 

Processing plant and paratyphoid Salmonella control

The processing plant can have an important role in the control of Salmonella. This is true for countries that allow the use of chemicals like chlorine during the processing and in the chiller. Levels of 5, 10 or 20 ppm can contribute a lot in reducing contamination. There are other chemicals that can be used and are efficient as well. There are countries that allow only a very limited use of chemicals during the processing, which are not effective in the controlling Salmonella contamination.  

In this case, the focus for control has to be done before the broiler arrives for slaughter. Good hygiene, cleaning and disinfection contributes a lot in the control of Salmonella, therefore they cannot be neglected. There is a link between the processing plant and grow-out, which is the transport system, mainly the coops or cages. A lack of good disinfection of the cages can distribute the bacteria from a positive to a negative flock in the field. This system needs constant attention.

Broiler grow-out and Salmonella control

For typhoid Salmonella not much intervention can be done at grow-out for a positive flock other than treatment with antibiotics. Because of the short life of the broiler, infection by Salmonella gallinarum/Salmonella pullorum almost always comes from the breeder and not from the field.  

For paratyphoid Salmonella, the infection can come from the breeder, but can also occur during the rearing period. Various possible sources of infection are previous flock, delivered feed, rodents and wild animals, backyard chickens, neighbors, other animals in the farm, poor cleaning and disinfection, bird’s disposal and humans such as employees/visitors (Vatche, 2011).  

Considering that the port of entry is diverse, it is necessary to monitor them to understand where the main sources are found. In addition, a short downtime (less than 2 weeks) and increased bird density has a lot of influence in the presence and persistence of  paratyphoid Salmonella. As for breeders, good biosecurity procedure plays an important role in avoiding the entry of Salmonella. If the fasting before slaughter and the transport time are too long, Salmonella proliferation is also favored. Antibiotics are not very efficient in controlling Salmonella infection in grow-out. They can reduce the infection, but as soon as they are removed, the infection can return. Several other products such as: probiotics, organic acids, essential oils, herbs extract, acids, MOS and vaccines can be used to reduce/control Salmonella but they have to be part of a holistic program that includes biosecurity. Because of the complex epidemiology, if they are used alone the best benefit cannot be achieved. 

Reducing Salmonella Challenges in the Poultry Industry Despite Antibiotic Resistance

Antibiotics have been used effectively in poultry for many years, both as therapeutic and prophylactic agents, to comply with the national control plan. The extensive use and misuse of antimicrobials has dramatically increased the emergence and spread of resistant bacteria (Sengupta et al., 2013).  

The European Food Safety Authority and European Centre for Disease Prevention and Control reported that levels of resistance were generally higher in Salmonella spp. isolated from broilers than from laying flocks. This suggests that laying hens in Europe are probably treated with antibiotics less frequently than broilers. 

At the beginning of 2018, a summary EU report on antimicrobial resistance in poultry in Europe was published, highlighting moderate to high levels of resistance in Salmonella to several antimicrobials.  

Many European member states also detected colistin-resistant Salmonella in poultry. Third generation cephalosporins and most classes of fluoroquinolones are critically important to treat life-threatening salmonellosis in humans. The level of resistance to these two important classes of antibiotics is described in the same report as low to very low in Europe.  

Antibiotic-resistant Salmonella isolated at farm level may spread to humans through direct contact or contaminated meat (Dolejska et al., 2013). Since the ban on antibiotic growth promoters in many developed countries, poultry producers are looking for alternatives to control the bacteria during production. Organic acid feed additives are one alternative to antibiotics (Adil et al., 2010), as are feed additives containing cinnamaldehyde (Demir et al., 2005).

Efficacy of organic acids against Salmonella

Biotronic® Top3 is a feed additive that has been formulated to control Gram-negative bacteria in poultry production systems. It contains various ingredients, such as organic acids, cinnamaldehyde, and BIOMIN® Permeabilizing Complex™ on a sequential release medium (carrier).   

Until very recently, the use of organic acids or single chain fatty acids (SCFA) mainly focused on their efficacy outside of the gastrointestinal tract. An increasing number of studies have been published focusing on the use of SCFA as supporters of gut health and as preventive tools to avoid an uncontrolled proliferation of pathogenic bacteria.  

The exact mode of action of SCFA as gut performance promoters are not yet clear. However, it has been demonstrated that organic acids have a direct antimicrobial activity against pathogens such as E. coli and Salmonella, and they might contribute to gut health indirectly by improving digestibility. This ensures a proper feed digestion—meaning that less non-digested feed reaches the lower part of the intestine where it could feed opportunistic bacteria, leading to pathogen proliferation. 

Generally, the addition of Biotronic® Top3 to the diet of broilers reduces the total number of E. coli and Salmonella while creating a favorable environment for the proliferation of beneficial bacteria (Figure 4). 

Prevention against Salmonella Enteritidis gut colonization: Biotronic® Top3

In a trial performed in cooperation with the Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna (ISZLER – Italy), Biotronic® Top3 was evaluated as a tool to prevent gut colonization by Salmonella Enteritidis in experimentally infected broilers. The group partitioning is listed in Table 6.

Table 6. Group partitioning and diet description. 

Group Treatment No of animals
Control Standard feed 20
Group 1 Standard feed + Biotronic® Top3 at 1.0 kg/T 20
Group 2 Standard feed + Biotronic® Top3 at 2.0 kg/T 20

Animals were fed a control diet without the addition of any additive or the same diet supplemented with 1 or 2 kg/ton of Biotronic® Top3. a,b Means with different superscripts differ significantly (P<0.05)

Diets were fed from day 1 to day 25 

At 15 days of age all the specific pathogen free animals were eye-drop infected with 1x105 CFU Salmonella enteritidis, a field strain isolated in Italy. At 5 days post infection, 10 animals per group were sacrificed and cecum was subjected to bacteriological analysis for the recovery of Salmonella enteritidis.  

Results are shown in Figure 8, and clearly indicate that in both treatment groups the counts of S. enteritidis were significantly reduced on both day 5 and day 10 post infection. Converting log reduction in percentages both trial groups had between 50% and 70% lower Salmonella counts compared to the control group. 

Figure 7. Salmonella Enteritidis counts (logCFU/g) in the cecal content of broilers on day 5 and 10 post infection. Source: BIOMIN

Figure 8. Bacterial counts (logCFU/g) of cecum microbiota in broilers at age 42. 
Animals were fed a control diet without the addition of any additive (grey) or the same diet supplemented with 1 kg/T of Biotronic® Top3 (green). a,b Means with different superscripts differ significantly (P<0.05). Source: BIOMIN

Salmonellosis Solutions

  • Balancius®

    Together DSM and Novozymes have created Balancius® the first and only feed ingredient designed to unlock the hidden potential in gastrointestinal functionality.

  • PoultryStar®

    PoultryStar® is a well-defined, multi-species poultry probiotic plus prebiotic (synbiotic) that promotes a beneficial gut microflora and improves the results of broilers, layers and breeders.

  • CRINA®

    Our specific blends of essential oil components have shown to help deliver a better balance of gut microflora.

  • CYLACTIN®

    Increase the proportion of ‘good’ bacteria, and you have a better performing gut.

  • DHAgold™

    With DHAgold™ we bring you a sustainable source of DHA to enrich poultry, swine and aqua.

  • Biotronic®

    The Biotronic® line of state-of-the-art enhanced acidifiers support modern farm animals against Gram-negative bacteria.

  • Biomin® CleanGrain Plus

    Biomin® CleanGrain Plus is a unique blend of organic acids and salts designed to protect against spoilage of grains and by-products caused by molds, yeast and bacteria.

  • Digestarom® DC Power

    Digestarom® DC Power is a next generation phytogenic feed additive mixed into premixes, mineral feed or finished feed in order to support farm animal feed intake, support digestion and feed conversion. The Feed Converter.

  • Digestarom®

    Digestarom® line of phytogenics contain unique blends of herbs and spices, essential oils and other plant extracts to improve palatability and acceptance of feed, support digestion and overall performance of farm animals.

  • Symphiome™

    Symphiome™ is a complex glycan mixture technically defined as a Precision Biotic*. A first-of-its-kind microbiome metabolic modulator precisely designed to harness the power of the microbiome by modulating specific and highly conserved functional pathways to enhance the nutritional health and performance of the birds.

Related Downloads

OUR AMBITION

Salmonellosis diagnosis and Salmonella control on pig farms

Salmonella is an enteric pathogen that can infect almost all animals and humans. It is one of the major food safety hazards for humans. After a great sanitation effort in poultry sector to control the Gram-negative pathogen, Salmonella in pigs has now become a major concern.

Salmonella in pigs

Pigs can become infected and act as reservoirs of Salmonella. Salmonellosis in swine is caused by Gram-negative bacteria from the genus Salmonella. In order to ensure a high level of pig performance, farmers should pay close attention to farm management focusing on: Salmonella prevention, applying external biosecurity to avoid the bug entering the farm and internal biosecurity to void spreading the bug when already present in the farm.

Occurrence of Salmonella in pigs

Salmonella is capable of surviving at least 6 years or more in the environment (Funk et al., 2008). Therefore biosecurity related practice is highly relevant for reducing the risk of Salmonella in swine farming.There is an association between season and/or environmental temperature and Salmonella prevalence in finishing swine (Christensen and Rudemo 1998, Funk et al., 2001). According to Rajic et al. (2007) pigs fed pelleted rations were at increased Salmonella risk compared to those fed mash feed.

The most frequently isolated Salmonella serotypes in pigs (Lowell and Barrow, 1999; Astorga et al., 2007) are:

  • - S. Typhimurium
  • - S. Choleraesuis
  • - S. Derby
  • - S. Brandenburg
  • - S. Bovismorbificans
  • - S. Newport
  • - S. Bredeney
  • - S. Anatum
  • - S. Hadar
  • - S. Goldcoast

Food safety and Salmonella in swine

Although the poultry sector has made great strides in controlling Salmonella in poultry flocks, the occurrence of this pathogen in swine has now become a major concern.

Salmonella is capable of surviving at least six years or more in the external environment.  Effective Salmonella control on farms requires robust biosecurity measures to prevent Salmonella from entering and spreading. Regular testing and observation at the critical points of the production chain are essential.

Salmonella-induced diseases can occur in every stage of swine production, but piglets are most sensitive to the pathogen. In sows, Salmonella can sometimes cause clinical diseases such as fever, depression, septicemia, pneumonia, meningitis, arthritis and diarrhea. The weaning period is the highest risk period for the excretion of Salmonella. 

Weaned piglets

Salmonella-induced diseases can occur in each stage of pig production, but piglets are most sensitive to it. The compound feed of juvenile animals like weaning piglets is high in protein and mineral content (high B-value).

Diets with a high B-value increases stomach pH, almost jeopardizing the barrier function and decreases digestibility which provides a suitable environment for pathogenic bacteria. Low levels of amylase and trypsin activity have been observed in the immature digestive system of piglets.

Another stress factor which should be taken into consideration in the case of weaned piglets is the diminished passive immunity and less developed active immunity. Environmental stresses caused by grouping, a diet change from sow milk to solid feed, and moderate development of the gastrointestinal tract (GIT) can facilitate the occurrence of Salmonella disease.

Gestating and lactating sows

Salmonella spp. can sometimes cause clinical diseases in sows like fever, depression, septicemia, pneumonia, meningitis, arthritis and diarrhea. According to Magistrali et al. (2011) young sows are more likely to shed Salmonella than older animals.

The weaning period is the highest risk period for the excretion of Salmonella. Several factors could explain the increased Salmonella excretion at post weaning, such as stresses linked to the weaning and the significant reductions in feed and water immediately post-weaning.

Fattening pigs

Schultz et al. (2007) has demonstrated that 10- to 12-week-old pigs under cold-stress and market-age pigs that are heat-stressed (18-22 weeks old) are at a higher risk of Salmonella infection. By reducing the Gram-negative bacteria in the feed and GIT, FCR and average daily weight gain (AWDG) are improved.

Control

On-farm Salmonella control is an important issue which is directly linked to regulatory limits at slaughter and food safety. Effective Salmonella control on the farm is based on the prevention of Salmonella entering and spreading on a farm through robust biosecurity.

Regular testing and observing the critical points of the production chain are necessary for prohibiting Salmonella occurrence and contamination.

Breeder houses

There must be adequate Salmonella monitoring and control at the breeder farms. Control starts with getting healthy young animals to the farm. On arrival, the piglets should be Salmonella-free. Samples from transport equipment and feces should be taken to determine the Salmonella status.

Points of Salmonella control

The points of Salmonella control on pig farms include:

  • Breeder houses
  • Feed raw materials and compound feed
  • Water
  • Pests
  • Farm environment

Feed

Salmonella spp. is one of the major hazards for the microbial contamination of animal feed. Animal-derived protein and oil seed meal are the major sources of risk among feed materials, through which Salmonella may be introduced to industrial compound feed and feed mills.

International regulations require that food and feed are free from Salmonella. Appropriate process control and decontamination steps are needed during feed processing to reduce the contamination of feedstuffs and avoid the dissemination of contaminated feed to herds.

It has been demonstrated in experimental settings that animals can become infected by consuming Salmonella contaminated feed, which can be further carried over to products of animal origin.

It is important to check all raw materials, especially cereals and protein sources, for Salmonella contamination. Salmonella colonies are naturally unevenly distributed in feed and therefore, the detection and quantification of Salmonella can be difficult. Sampling feed from different places is necessary to get the representative feed sample for microbial analysis.

The heat treatment of feed is a common means of feed sanitation. However, it should be conducted appropriately in order to reduce bacteria counts, taking into account, in particular, temperature, duration and initial bacterial counts. Moreover, heat treatment does not protect feed from recontamination during transportation and storage, Figure 1 shows.

Figure 1: Recontamination of feed without acidifier
Source: Israelsen et al., 1996

Water

Salmonella can persist and grow in water given the right conditions. The diversity and concentration of Salmonella increases as temperatures rise. For better Salmonella control, a microbiological test of water is needed, especially if the source of water is a well or river. Drinking water for animals should have the same high standards that are suitable for human consumption. The results of the two sampling from the start and end points of watering line, and the difference between them, gives a clear picture if improvements in water quality that have to be made, if any.

Pests

Since all vertebrates are susceptible to Salmonella infection, contact with other species may pose an infection risk to animals. Pests (pets, rodents, wild birds, and other wildlife species) have often been implicated as potential sources of Salmonella. It has been recognized that flies and beetles also serve as a potential reservoir and vectors for Salmonella. It is therefore important to ensure proper vermin and pest control on the farm.

Feces

Salmonella is a common component of the gut microflora of animals and thus, can be found in the feces of affected animals. Fecal pollution is the main culprit for the contamination of feed and water with Salmonella.

Farm hygiene and biosecurity

Contamination of the resident environment of animal housing can be a source of Salmonella infection. Keeping buildings clean and disinfecting farm equipment helps to minimize the danger of infection.

Improving farm personnel hygiene and the control of visitors are important factors for reducing risk of Salmonella. Hand washing and disinfection as well as the cleaning of overalls and disinfection of boots before entering the stable are associated with decreased Salmonella prevalence. The relatively small cost incurred may offset a decreased transfer of other performance impairing pathogens.

Main biosecurity practices that can also reduce/control Salmonella prevalence include:

  • Changing of clothing and boots prior to entering or leaving the pig area
  • Cleaning and disinfection protocols (facility, feeders and drinker equipment)
  • Pig flow practices (all-in/all-out pig flow)
  • Welfare standards such as density and ventilation

Solutions

The use of acidifiers or organic acids in the feed or drinking water can reduce the risk of Salmonella in swine farms. Research has shown the direct relationship between acidity level and Salmonella prevalence in pigs (Alborali et. al., 2012).

Acidifiers exert their mode of action not only in compound feed but in the gastrointestinal tract (GIT) as well. Thus, the effects of organic acids may be targeted at three different areas: the feed, GIT and intermediary metabolism leading to improved feed conversion rates (FCR), digestibility of nutrients and reduced diarrhea (scours), morbidity and mortality rates (Figure 2).

Figure 2. Mechanisms of organic acids in feed, water, gastrointestinal tract and intermediary metabolism.

Combating Salmonella in swine

Using acidifiers or organic acids in the feed or in drinking water can reduce the risk of Salmonella on swine farms. Acidifiers act not only in compound feed but in the gastrointestinal tract as well.

The use of organic acids in feed supports environmental hygiene by protecting feed raw materials and compound feed against microbial and fungal deterioration. Moreover, it contributes to good farm management and interrupts bacterial transmission in the animal-to-food chain.

The use of acids in drinking water reduces the pH level and bacterial counts.

Acidifiers in feed

The addition of organic acids has been shown to contribute to environmental hygiene by preventing feed raw materials and compound feed from microbial and fungal deterioration. Moreover, it contributes to good farm management and interrupts the bacterial transmission in the animal-to-food chain.

A multiple strategy encompassing heat and antimicrobial treatments, for instance, with organic acids, is required for the reduction of bacterial burden and improvement of feed hygiene.

Acidifiers in water

Water acidification can help prevent Salmonella. The supplementation of acids in drinking water reduces the pH level and bacterial counts. The reduction of pH value in water creates unfavorable conditions for potentially harmful bacteria proliferation.

Tip: It’s important to know knowing the pH level of water when determining the right dosage of acidifiers to pigs’ drinking water.

Salmonellosis Solutions

  • VevoVitall®

    VevoVitall® is an ultra-pure source of benzoic acid and is an excellent feed preservative.

Share

Share