Currently, the world egg production is of 76 million tons and the global average egg consumption is around 161 eggs per person a year. According to projections, demand will continue to increase. The consumer is demanding eggs of a better quality in terms of cage-free hens and organic or more sustainable production.

Thanks to the genetic selection of the laying hens, progresses is made towards increasing efficiency and productivity. In this context, producers must commit to maintaining intestinal welfare, which will be a critical component to maximize the genetic potential of these birds. Veterinarians, nutritionists, and farm workers will need to learn to measure and asses the indicators of intestinal welfare as often as necessary.

Today, the industry has invested in the research of different tools aimed at improving intestinal welfare while reducing the use of antibiotics and other drugs. Thus, additives of natural origin have emerged, such as intestinal conditioner pronutrients, diatoms and the cimenol ring. They all contribute to maintaining and improving intestinal welfare, essential to obtain better production rates (laying rate, % of dirty eggs, quality internal and external egg). These have advantages over other additives since they have a proven efficacy and are chemically defined and composed of active molecules with a fully described mechanisms of action.

Intestinal welfare in laying hens

For hens, the beginning of the laying period is key, as a relatively high number of problems can occur with a possible negative impact on productivity. The laying percentage increases rapidly during the beginning of this phase; however, feed consumption does not increase proportionally. As a result of this challenge, there may be a negative balance of nutrients and, to avoid it, a healthy intestine together with a balanced microbiota are essential to make the most of the nutrients provided in the diet.

The following must be considered as indicators of intestinal welfare problems: a drop in the percentage of the daily laying rate, the percentage of dirty eggs, the consistency of feces, low gain or loss of live weight, a weight and size of the egg below expectations and a change in the feed/water consumption ratio, mainly.

The problem of dirty eggs

The percentage of dirty eggs is a valid indicator of optimal intestinal welfare. The quality of the egg in terms of its cleanliness is something of special importance in the poultry industry due to the economic losses it generates.

This problem is related to multiple factors, among which we highlight health, nutrition, handling, hygiene plan, the facilities, and age of the hen.

Within health, the bacterial load and intestinal integrity are two key factors to keep the percentage of dirty eggs within the appropriate limits. Alterations in these factors produce symptoms of rapid transit and more liquid stools. It is indeed the decrease in the consistency of the stool that generates the most dirt in the eggs. Any infection that affects intestinal transit, whether of bacterial, viral, or parasitic origin, may also increase the percentage of dirty eggs.

Dysbacteriosis or imbalances in the bacterial load are often caused by the excessive administration of antibiotics used as therapeutics or as growth promoters.

Poor intestinal integrity will lead to poor nutrient absorption and an excess nutrients in the intestinal lumen, which creates a suitable environment for the proliferation of pathogenic bacteria.

Among the problems of dirty eggs derived from nutritional causes we can highlight:

• Diets with a high percentage of non-starch polysaccharides, found in certain cereals such as rye. They produce an increase in the viscosity of the stool, making it more pasty and staining the cloaca and, later, the egg.
• Sudden changes in the feed formula can produce imbalances that affect the consistency of the stool.
• Errors in the feed formula, such as a high concentration of mineral salts, can cause osmotic-type diarrhea.
• Deficiency of pronutrients (developed in section 4.1).
• Accelerated intestinal transit.

New opportunities to improve gut welfare through nutrition are now available to avoid or solve these situations, which help to replace antibiotics. Understanding the role of nutrition beyond the mixture of raw materials, considering the necessary additives, will help to obtain a proper feed digestion and nutrient absorption, together with a balanced microflora.

Natural additives to improve intestinal welfare

The use of natural additives based on intestinal conditioners pronutrients, diatoms and the cimenol ring are solutions that meet the current demands related to poultry farming, have advantages over other additives, have a proven efficacy, are chemically defined, and are composed of active molecules with fully mechanisms of action described.

• Intestinal conditioners pronutrients

Intensive production does not allow laying hens to have access to certain plants, a fact that alters the intestinal welfare due to pronutrient deficiency. That is why there are natural additives based on pronutrients that provide the birds raised in the farms with plants’ essential molecules.

Pronutrients are active molecules of plant origin that improve intestinal physiology. The mechanism of action has been studied by Biovet S.A and is based on their metagenetic action, by which they stimulate specific DNA genes that improve the functionality of enterocytes. They act as an external stimulus, increasing the synthesis of functional proteins by the enterocytes, which is reflected in a greater regeneration of the cells of the intestinal mucosa, increasing the absorption of nutrients.

They also improve the status of the tight junctions between the enterocytes, which are composed of proteins (occludins, claudins) responsible for maintaining the good state of the paracellular space, the site through which infections may reach the organism. Therefore, pronutrients are key to good intestinal integrity.

Pronutrients exert their beneficial effect by improving nutrient absorption and intestinal integrity; the better use of the nutrients presents in the diet together with the increase in the regeneration of the enterocytes and the reinforcement of the tight junctions control the challenges caused by enterobacteria, avoiding the loss of consistency of the stool and, consequently, reducing the percentage of dirty eggs. Their results are very visible at certain moments of the production cycle, especially during the rearing phase, at the beginning of laying, as well as at the peak of laying, to get it to be high and sustained, and also at the end of the laying cycle, so that the decrease in production will be less abrupt and the quality of the egg will be maintained.

• Cimenol ring: natural antimicrobial

It is a substance of natural origin with antimicrobial capacity. The cimenol ring is present in different aromatic plants (thyme, rosemary, sage, etc.) and acts as an intestinal biocide, controlling pathogenic bacteria, both gram-positive and gram-negative (Clostridium, Salmonella, E. coli, Campylobacter, among others), while it does not affect the beneficial bacteria.

The effect of the cimenol ring can be enhanced by combining it with citric acid (Alquermold Natural), producing a synergism, since citric acid generates pores in the bacterial membrane facilitating the entry of the cimenol ring into the cell, which destabilizes the plasma membrane and causes the death of the microorganism. The combined action of these two active compounds has been patented by Biovet S.A, which has studied this mechanism of action through its R&D department.

The antimicrobial effect of the cimenol ring modulates the bacterial load. This way, it prevents the infections caused by Enterobacteriaceae that alter the consistency of the stool, avoiding losses due to dirty eggs.

In the latest tests carried out during 2020, the effect of the cimenol ring in reducing dirty eggs has been verified, achieving improvements of up to 81.15% compared to commonly used treatments.

The cimenol ring can be combined with intestinal conditioner pronutrients, since the first acts directly in the control of microorganisms and pronutrients improve the integrity of the epithelium, thus, there is synergism between both natural solutions.

The cimenol ring has a dual effect, since, in addition to being an intestinal biocide, it is a preservative of raw materials and compound feeds. Additionally, it is a safe product that does not generate bacterial resistance, lacks a withdrawal period, and leaves no residue.

• Diatoms: regulator of the intestinal passage rate

Rapid transit in birds is a frequent problem on farms, characterized by the presence of partially undigested feed in the droppings and watery faeces. When feed does not remain for long enough in the intestine, nutrient absorption is reduces and so is the quality of the stool, which increase the percentage of dirty eggs.

The R&D department of Biovet S.A has developed a product based on diatoms (Thalassiosira and Actinoptychus) that has a slowing effect on the intestinal transit of birds.

The diatoms in the product have received an activation treatment, so that the pores located on diatoms’ surface have a high capacity to include water inside, thus reducing the volume of intestinal content that stimulates peristalsis. Water retention translates into a lower speed of intestinal transit and better consistency of the stool.

The supplementation of the feed with activated diatoms also allows to increase the retention time of the feed in the digestive tract, so that there is more contact with digestive enzymes and intestinal microvilli; this has a positive effect on the growth rate and feed efficiency.

Conclusions

World egg production continues to grow year by year. In the short term, more countries will have to maintain production rates by reducing the use of antibiotics, as there is a global trend towards a more sustainable production.

In the trials, it was observed that the use of pronutrients improved the laying index by 2.9%, while the consistency of the stool significantly improved. With the use of the cimenol ring, important differences were observed in the reduction of dirty eggs of up to 81.15% compared to a batch that received formaldehyde and 55.79% versus a batch that received organic acids, which shows the good control that it exerts on the bacterial load.

with the natural tools, like intestinal conditioner pronutrients, diatoms, and the cimenol ring to enhance gut welfare are effective in terms of productivity, profitability, and sustainability.

• The cimenol ring is marketed by BIOVET S.A under the trade name Alquermold Natural. It is available in premix and liquid.
• Intestinal conditioners pronutrients are marketed by BIOVET S.A under the trade name of Alquernat Nebsui. It is available in premix and liquid.
• Diatoms are marketed by BIOVET S.A under the trade name Alquerfeed Diatom. It is available in premix.