Laying hens farming is focused on producing high-quality and safe eggs and, in addition, maintain a healthy status of the animals. In order to achieve these objectives, the use of vaccines and antibiotics (whether as prophylactic, therapeutic or to improve the performance) is widespread.

Nowadays, however, due to the important role that livestock has played in the development of antibiotic microbial resistance, producers are forced to look for alternatives to antimicrobials that are capable of maintaining or improving production levels, while reducing the negative effects of antibiotics.

Regulations, assuming their role in public health, mark new restrictions on drug utilization, together with the growing demand from consumers of drug-free products, are also an additional support for the use of alternative solutions.

Currently, there are already a wide variety of alternatives for antibiotics. However, there are still producers who are not sure of maintaining egg quality and hens’ sanitary status without using antibiotics. Our goal is to introduce some alternatives which have demonstrated effectivity to improve egg quality and health status of hens.

Integrity and intestinal health in egg production

A well-known topic is the relationship between intestinal health and the productive rates of laying hens. The use of therapeutic or preventive antibiotics and promoter antibiotics (AGP) focuses on controlling certain pathogenic microorganisms, favoring the growth of beneficial flora. This concept is valid and is also the objective of prebiotics, probiotics and products based on plant extracts.

If looking for a complete and complementary strategy, we must work on the microbiological quality of the food, on the balance of the intestinal flora and the integrity of the intestinal epithelium.

One of the most known compounds which fulfill a function according to this strategy is the cimenol ring. It a molecule of plant origin, characterized by its bactericidal and fungicidal properties. It works as a dual purpose tool, as it reduces the microbiological load of feed and, once in the digestive tract, it promotes the balance of the intestinal flora and controlls pathogenic microorganisms. There are multiple in vitro and in vivo assays that demonstrate its efficacy in the control of Clostridium perfringens and Salmonella sp. Clostridium perfringens is responsible for necrotic enteritis outbreak, an acute disease with high mortality rates, and Salmonella causes a zoonotic disease of public health relevance. Inactivated Salmonella vaccine can be supplemented with cimenol ring to control the disease. Vaccine generates specific immunity against the agent and the cimenol ring reduces the bacterial load, preventing reinfections.

Products based on plant extracts that improve intestinal integrity are also an option to replace pharmacological compounds. They have common components that can be grouped as intestinal conditioner pronutrients. Pronutrients are biologically active molecules that induce the expression of genes involved in intestinal physiology. Intestinal conditioners, on the one hand, increase the rate of regeneration of enterocytes, which improve the absorption of nutrients. On the other hand, pronutrients improve tight junctions. Tight junctions regulate paracellular permeability between enterocytes, creating a barrier that prevents the passage of toxins and microorganisms, but allows the passage of nutrients.

The intestinal conditioner pronutrients are natural growth promoters and control the entry of paracellular infections, acting as replacers of antibiotic growth promoters (AGP). Several trials have been performed to compare AGPs (bacitracin, colistin) against intestinal conditioners, showing both batches similar performance results.

Pronutrients are also able to improve the egg internal quality (colour, size and resistance of the yolk), due to a better absorption of nutrients (vitamins, minerals, pigments).

Another alternative to AGP is probiotics, bacterial strains grown in fermenters and used to promote the balance of the intestinal microbiota. The most common microorganisms used as probiotic are: Lactobacillus, Bifidobacterium, Enterococcus, Bacillus, Streptococcus and some yeasts such as Saccharomyces. Probiotics compete and attach to the same binding sites that pathogenic bacteria. In addition, they produce certain protective metabolites such as fatty acids, hydrogen peroxide and bacteriocins that prevent the growth of pathogens.

The new trend is to combine probiotics with products based on natural extracts, since they are complementary and the results are very auspicious.

IMMUNO STIMULATION

When replacing antibiotics, different strategies to stimulate the immune system should be considered to prepare the animals to fight challenges adequately.

Immunization by vaccination is a very useful tool with excellent results. Developing and executing a health plan adapted to our problem is necessary and fundamental in any farm.

The effectiveness of vaccination is widely proven. However, there are vaccine failures due to mishandling, error in the route of administration, incorrect timing, cold chain breakage, low immunogenic strains, etc.

To support or supplement vaccination, there are available natural immunostimulants based on plant extracts. These extracts are rich in immunostimulant pronutrients, which enhancer the specific and nonspecific immune response, increasing the production and persistence of antibodies.

The use of immunostimulants is important to counteract the different factors that cause immunosuppression. These include mycotoxins (aflatoxins, ochratoxin), infectious causes (Marek’s disease, Gumboro’s disease, infectious bronchitis), stress, air quality, population density, etc.

Immunostimulant pronutrients can be used strategically or in a pulsatile manner. In support of vaccination, they are administered 5 to 7 days prior to vaccination and 5-7 days after. Pulse administrations of 15 days are recommended to improve the immune status and, thus, reduce the presentation of diseases. These periods are adjusted to each farm needs.

HEPATIC PROTECTION FOR INTERNAL QUALITY OF THE EGG

The liver is a basic organ to ensure a proper internal quality of the egg. 50% of the protein synthesis, done in the liver, is destined to egg production. It is also responsible for synthesizing part of the fat that makes up the yolk.

It plays a fundamental role in the state and effectiveness of the immune system, since the liver is responsible for the production of immunoglubulins.

Due to its purification function, it is constantly threatened by different agents: drugs, metabolic overload, microorganisms, mycotoxins, etc. These challenges will be always present and, therefore, it is recommended to use natural additives with hepatoprotective function.

As an example, prolonging the productive life of a layer hen up to 100 weeks of laying is a challenge that depends largely on the liver condition.

Natural hepatoprotective solutions are products based on plant extracts, rich in hepatoprotective pronutrients. These pronutrients act as liver regenerators and protectors, increasing protein synthesis and bile secretion.

CONCLUSIONS

Nowadays, production of eggs without antibiotics is a reality. Research and product development has provided us the new tools to achieve this type of production.

All actors in the food chain must be aware and know that the same production rates can be maintained without using antibiotics.

By producing eggs in a more friendly way, it can be avoided the growth of bacterial resistance, eggs produced do not contain residues and, at the same time, the productive rates are maintained.

It should be noted that the production of antibiotic-free eggs is not the same as organic or ecologic production. Ecologic production has several requirements regulated by the livestock ministries of the different countries. Adapting to a production without antibiotics does not require anything other than the producer’s decision.

The purpose of this article was to mention some of the available tools. Undoubtedly, the combination of different strategies should be considered to maintain: intestinal health and integrity, microbiota balance, immunity and liver condition.

Intestinal conditioner, hepatoprotective and immunostimulant pronutrients, as well as the cimenol ring, have proven to be an effective and alternative tool to antibiotics and other drugs.