Natural betaine as an effective rumen modulator

Iris den Teuling and Veronique Lemmerling, E.F.S.-Holland B.V. & Ana Gavrău, AGRANA Sales & Marketing GmbH

ActiBeet^® liquid – a natural betaine – was introduced into the animal feed sector by Agrana GmbH in 2015. Agrana is now expanding her portfolio with a new crystalline betaine: ActiBeet^® 96. E.F.S. is delighted to fulfil its role as distributor again.

It is well known that ActiBeet^®/betaine plays a key role in the metabolism of monogastric animals. However, the role of betaine in ruminants and the rumen activity is underexposed until now.

Ruminants are dependent upon ruminal microbes that enable the formation of short-chain fatty acids (SCFAs) and microbial protein synthesis by fermenting feedstuffs. SCFAs and microbial proteins are the main source of energy and protein in ruminants. Therefore, proper fermentation in ruminants is crucial and climatic and dietary shifts can suppress fermentation. Rumen osmolality and temperature are important physicochemical parameters that impact the fermentation by affecting the activity, survival and balance of the ruminal microbial population.

It has been shown that high-concentrate feeding, especially in high-yielding cows, elevates the temperature and osmolality of the rumen content. It is assumed that osmotic pressure influences the voluntary dry matter intake. As a result of such physicochemical changes, the metabolism and growth of ruminal microbes are placed under thermal and hyperosmotic stress. Depending on the severity, this can compromise the stability of the rumen ecosystem and thus animal health, and ultimately the farmer’s revenue.

Climatic stress as well as high-grain feeding can lead to a number of physiological challenges in cattle. Ration is the largest determining factor of rumen microbial stability. This modulatory potential is a promising way to improve ruminal fermentation and to ensure energy supply.

Natural betaine: ActiBeet^® 96

Natural betaine, as a non-ionic osmolyte and a methyl group donor is well studied and successfully used in the feed of monogastric animals. Betaine is a proven nutritional aid against heat and osmotic stress. As an excellent organic osmolyte, betaine protects the enzymatic and cellular integrity and functionality. Furthermore as a methyl group donor, betaine provides methyl groups for synthesis of numerous substances, as an intermediate product in protein and energy metabolism. Betaine is also used very efficiently in industrial fermentation processes in order to increase the output of the final product (vitamins or aminoacids). The above mentioned characteristics make betaine suitable to normalise microbial cell physiology, perturbed during heat and osmotic stress.

In ruminants, microbial metabolism of natural betaine is known, but the extent to which ruminal microbes use betaine has been underexplored. Microorganisms can use betaine as an osmolyte to adapt to external stressors and as a potential methyl group donor. Because of these properties, betaine could modulate ruminal fermentation. Therefore, it might be more significant to ruminal microbes during stress than previously thought.

In collaboration with the team of Professor Qendrim Zebeli from the University of Veterinary Medicine Vienna, Austria, in vitro study was carried out recently. This study aimed to test natural betaine from ActiBeet^® L as a possible effective rumen modulator under normal physiological and stressed rumen conditions.

A rumen simulation technique (RUSITEC) was used to evaluate the effects of betaine supplementation on rumen fermentation variables, microbiome and nutrient digestibility under normal, heat-stressed and hyperosmotic-stressed rumen conditions. The basal diets were high in non-fibre carbohydrates representing a common diet for high-yielding dairy cattle.

Three different betaine doses (ActiBeet^® L, 40% betaine) were used: 0% (control), 0.3% of diet DM (low), and 1.7% of diet DM (high). Each dose was tested under two incubation temperatures: normal rumen and heat-stressed rumen temperature and two osmotic conditions, including normal rumen osmolality and hyperosmotic conditions. The osmolarity and pH of incubation fluid for normal and hyperosmotic conditions were successfully determined through the amount of concentrate in the diet and modified buffer. There were six runs in total, each run included the adaptation and measurement periods to determine fermentation characteristics. All trial data were analysed by the MIXED procedure of SAS.

Short-chain fatty acids gains

The major finding was that betaine supplementation increased the concentration of short-chain fatty acids (SCFAs) in heat-stressed rumen conditions (Figure 1):

Figure 1. The concentration of total SCFAs in incubation fluid (mmol/l)

SCFAs are a major source of energy in ruminants providing up to 75% of the metabolizable energy. Without betaine, the heat-stressed condition clearly decreased the SCFA concentration, which indicates that heat stress leads to a depression in milk production. The negative effect of heat stress on suppressed SCFA concentration disappeared when betaine was supplemented to the ration and the concentration of the SCFAs increased linearly with betaine dosage.

More propionate under hyperosmotic rumen conditions

Under normal rumen conditions betaine is converted to acetate, which is utilised for milk fat synthesis. Under hyperosmotic conditions, an increased dosage of betaine leads to an increased propionate proportion,resulting in a pronounced decrease in acetate:propionate ratio (Figure 2).

Figure 2. The proportion of acetate and propionate (mol/100 mol) as affected by betaine supplementation and osmotic‐stressed rumen conditions.

Propionate is an important glucogenic precursor in ruminants and is used for lactose production, which is a key determinant for milk yield. Therefore, the results suggest that betaine could be used to promote energy supply from propionate and increase hepatic gluconeogenesis in times of osmotic‐stressed rumen conditions.

The in vitro dosage, after correction, can be translated into the following practical dosages: 6 g of betaine/cow /day, as a practical low dosage; and 36 g of betaine / cow / day as a practical high dosage.

Conclusion

Hyperthermal and hyperosmotic stress are typical stressors caused by feeding as well as a high ambient temperature. Both stress conditions can lead to poor fermentation and subsequently adverse effects on ruminant productivity. According to our data, heat and hyperosmotic stress clearly suppresses rumen fermentation and natural betaine promotes microbial fermentation activity, making it an effective rumen modulator.

Betaine supplemented to grain-rich diets enhances microbial fermentation leading to more SCFA production during heat stress and it minimisesthe effect of hyperosmotic stress by decreasing the acetate:propionate ratio. The increase in propionate percentage upon betaine addition under the hyperosmotic stress suggests that betaine supports fermentation by means of dominating microbes.

Betaine, as a substrate and methyl donor for microbes directly modulates ruminal fermentation and as a compatible osmolyte betaine can enable microbial tolerance to stressors.

Rumen microbes may fully benefit from the available betaine and use it to battle thermal and hyperosmotic stress in a way that helps to retain their fermentation activities, which arecrucial for ruminant health and productivity.

References:
References are available on request.

Definitions
Osmolality: osmoles of solute per kilogram of solvent (Osm/kg)
Osmolarity: osmoles of solute per liter of solution (Osm/L)