Nutrient and Oxalate Acid Content of Brachiaria Grass Species

Brachiaria grass is used mostly as a pasture plant; it has good production and grows well under marginal conditions of low soil fertility. Brachiaria grass comes from the African region and has spread in the Asia and Pacific regions.

Grasses have relatively few intrinsic toxins. Grasses that contain intrinsic toxins include tropical grasses (oxalate and saponin). The effect of oxalate is bone demineralization. Oxalate reacts with calcium to produce insoluble calcium oxalate, reducing calcium absorption¹. Oxalate acid has an anhydrous, crystallized from glacial acetic acid. It is an odorless white solid. Oxalate acid has the ability to form strong bonds with various minerals, such as sodium, potassium, magnesium and calcium².

The role of oxalate acid in plants includes; calcium regulation, ion balance (Na and K), protecting plants, tissue support and heavy metal detoxification. The oxalate acid content in plants is influenced by season, species and botanical fraction. Soluble oxalate is readily absorbed in the systemic circulation and could react with blood Ca, causing hypocalcemia. Oxalate forms insoluble crystals of calcium oxalate, which inhibit the kidney tubules³.

Information regarding the levels of oxalate in Brachiaria is limited and increasing the knowledge base regarding the oxalate acid and nutrient content in these species could result in a more efficient use of this forage. Therefore, a new study was undertaken to improve the information regarding seasonal and varietal effects, nutrient content and oxalate botanical fractions in various Brachiaria spp⁴.

The nutrient values of the botanical fractions from four species of Brachiaria in different seasons were evaluated. The dry matter, ether extract, crude protein and crude fiber of Brachiaria spp. stems showed significant differences. The nutrient values in the dry season were higher than those in the rainy season. The highest oxalate acid content occurs before the rainy season begins and the oxalate acid value can reach 6% or more. The oxalate acid content in the tropics is higher than that in the subtropics.

Based on this study, it can be concluded that different seasons, species and botanical fractions did not significantly affect the oxalate acid content. Many environmental effects, including temperature, day length, and hours of sunlight and flowering induction associated with seasonal change, may also change oxalate levels. The nutrient values (DM, EE and CP) of Brachiaria spp. in Indonesia were significantly different.

Keywords:

Botanical fraction, oxalate acid, Brachiaria spp., season, bone demineralization, intrinsic toxins, tropical grasses, oxalate and saponin.

References:

1. Cheeke, P.R., 1995. Endogenous toxins and mycotoxins in forage grasses and their effects on livestock. J. Anim. Sci., 73: 909-918.
2. Liebman, M., 2002. The truth about oxalate. The Vulvar Pain Newsletter, Number 22.
3. James, L.F. and J.E. Butcher, 1972. Halogeton poisoning of sheep: Effect of high level oxalate intake. J. Anim. Sci., 35: 1233-1238.
4. Umami, N., Suhartanto, B., Suwignyo, B., Suseno, N. and Herminasari, F., 2018. Effects of Season, Species and Botanical Fraction on Oxalate Acid in Brachiaria Spp. Grasses in Yogyakarta, Indonesia. Pak. J. Nutri., 17: 300-305.