Betaine use in broiler diets

In poultry nutrition, it can contribute in improving carcass performance and composition, reducing bed moisture, and helping to overcome coccidiosis and stress.

Thermal stress

Thermal stress consists of exposing birds to temperatures which are higher than optimal. This causes numerous health problems, such as:

• Respiratory deficits
• Decreased feed intake
• Lower weight at marketing age.

Heat stress represents one of the most important factors with negative effects on poultry production.  It also has negative effects on carcass properties, which results in lower meat quality.

 The use of feed additives that have positive effects to help resist thermal stress represent the most significant solution for this problem.

Betaine, has other beneficial effects on mild heat stress.  Most studies have shown slight positive effects; however, systematic results are scarce. Since betaine dosage and product possibilities are almost limitless, more research is still required on this subject.

Metabolism and functions

Betaine is absorbed in the jejunum of chickens in its purified form.  Its absorption is faster than that of choline or methionine. The latter are associated with plasma lipoproteins, while betaine remains free in plasma.  Choline must be transported from the cytosol to the mitochondria, where it is oxidized to betaine.

However, the efficacy of choline to betaine conversion is reduced by ionophore anticoccidials commonly used in poultry farming.

In chickens, betaine can donate a methyl group (CH3) to homocysteine for methionine synthesis three times more efficiently than choline. However, an adequate concentration of cysteine is necessary in order to achieve the beneficial effects of betaine supplementation.

An inadequate concentration of cysteine in the diet can affect betaine activity by reducing homocysteine concentrations for methionine formation.

The accumulation of bataine causes an increase in the water retention capacity of intestinal cells and promotes changes in the structure of the intestinal epithelium that increase intestinal surface. It also stimulates cell proliferation in intestinal tissue, especially in the mucous membrane. Increased epithelium of the intestinal wall can increase the nutrient absorption surface.

⇒ Reducing intestinal pH and intestinal villus height with betaine (hydrochloride) supplementation in the stomach may improve the digestibility of methionine and other nutrients.

Improved performance

The influence of betaine supplementation on broiler performance depends mainly on the concentrations of other labile methyl groups in the diet and the stress that the bird has at that time. Betaine supplementation did not influence the performance of birds in diets with adequate or severe methionine deficiency.

However, an improvement has been reported in:

• Body weight
• Breast meat yield
• Feed conversion
• Decreasing the weight of abdominal fat pads

The results of a recent study indicate a significant improvement in feed efficiency in broilers which were fed betaine (800mg/kg) or suboptimal methionine concentrations compared to those fed without its inclusion, regardless of amino acid concentration.

Dose

In general, the recommended concentration of betaine in feed is 500-750g/tonne.

→ Its use can be reduced to a higher concentration (>800g/tonne).

Conclusions

The osmotic properties of betaine are useful in helping to maintain the integrity of the intestinal mucosa under heat stress and digestive disorders.

As a methyl donor, it participates in the synthesis of methionine.

It has also been reported to improve breast meat yield in broilers.

Source: ResearchGate. Application of betaine as feed additives in poultry nutrition – a review