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Malic acid treatment may reduce methane emissions from ruminant digestion

TAGS: Beef Dairy
branex/iStock/Thinkstock beef cattle in pasture
Researchers from Spain reduce methane and ammonia emissions generated by ruminant digestion by treating protein meals with malic acid and heat.

Modifying the diet in a controlled manner helps reduce methane and ammonia emissions generated during ruminant digestion, according to researchers from the Universidad Politécnica de Madrid (UPM) in Spain.

The research has shown that the treatment of proteins in their diet to reduce their degradation in the rumen can reduce the methane emissions produced in the ruminal fermentation by more than 10%, according to a translated press release from UPM. Although these results have been obtained in vitro and still need to be confirmed in vivo, they could open up interesting possibilities for the development of new animal nutrition strategies, the researchers said.

Animal nutrition is continuously fine-tuned with the aim of increasing both the nutritional efficiency and the production and quality of foods of animal origin in order to meet the growing needs of the human population, UPM said.

The improvement of nutrition is even more imperative in the case of ruminants, because ruminants generate the greenhouse gas methane during the digestive process, which represents a significant loss of energy for the animal, UPM said. In addition, ruminants have low nitrogen use efficiency, so a high proportion of the nitrogen they ingest is excreted into the environment.

Faced with the traditional idea that the generation of methane in the rumen is basically conditioned by the contributions of fiber in the diet, recent work by the Animal Production Research Group of the Higher Technical School of Agronomic, Food & Biosystems Engineering (ETSIAAB -UPM) at UPM have shown that methane is also produced by the fermentation of proteins. This is due, predictably, to fermentation of the carbon chains resulting from the deamination of amino acids generated in protein degradation, the researchers said.

Accounting for these results, and with the aim of reducing the polluting emissions produced by these animals, the UPM researchers have studied the effects on digestion of minimizing the contents of degradable protein in ruminants' diets while also ensuring a level that does not negatively affect the growth of the rumen microbial population.

To do this, they applied treatments to the dietary proteins to cause their denaturation, thus protecting them from degradation in the rumen.

When choosing the most suitable food to apply the treatment, protein concentrates with a high content of highly degradable protein and essential amino acids were found, the researchers said, noting that sunflower seed and sunflower meal presented these characteristics and were rich in sulfur amino acids and tryptophan.

The protective treatment developed by the research group consists of treating the protein with an acidic solution and heat, UPM said.

"Malic acid is the one that has provided the best results and has the advantage that it is an acid that is also used as an additive to improve the efficiency of food use," UPM researcher Dolores Carro said.

The digestive processes feed would encounter in the rumen were simulated in vitro. To this end, diets were formulated with a moderate (13%) or high (17%) level of protein that had seed and sunflower meal as sole protein concentrates, and emissions studies were made after ruminal digestion of the untreated diet and after treatment with malic acid and heat.

According to Carro, "The results showed that, effectively, the treatment of the feed reduced the degradability of the sunflower protein and the nitrogen losses in the form of ammonia. In addition, the production of methane was reduced by 4.6% in the case of diets with a low protein content and by 10.8% in the diets with a high protein content.

"These results should be confirmed in conditions in vivo but open new possibilities for the development of animal nutrition strategies more respectful with the environment," Carro added.

The research was published in the following journal articles:

Haro, A.N., M.D. Carro and J. González. 2018. Protecting protein against rumen degradation could contribute to reduce methane production. J. Anim. Physiol. Anim. Nutr. 102:1482-1487.

Vanegas, J.L., M.D. Carro, M.R. Alvir and J. González. 2017a. Protection of sunflower seed and sunflower meal protein with malic acid and heat: Effects on in vitro ruminal fermentation and methane production. J. Sci. Food & Ag. 97:350-356.

Vanegas, J.L., J. Gonzalez, M.R. Alvir and M.D. Carro. 2017b. Influence of malice acid-heat treatment for protecting sunflower protein against ruminal degradation in vitro methane production: A comparison with the use of malic acid as an additive. Anim. Feed Sci. Tech. 228:123-131.

Source: Universidad Politécnica de Madrid, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.

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