Content available at:
Indonesia (Indonesian) Melayu (Malay) ไทย (Thai) Tiếng Việt (Vietnamese) Philipino
The development of poultry and swine farming systems with characteristics of intensive production has been supported by establishing a circuit that entails the production of balanced feed on a large scale.
In turn, balanced feeds have been structured based on the use of corn as the main energy component of the feed, with very particular advantages over other cereals, such as the fact that they do not have anti-nutritional compounds within their components.
However, since the 1970s, other cereals have been included in the formulation of commercial diets for poultry and pigs.
In South America, particularly in Venezuela, after corn, grain sorghum is the other cereal used by the balanced feed industry.
Most of these sorghums contain condensed tannins (CT) within their components, which have been linked in non-ruminants with an adverse effect on digestion and the metabolism of nutrients.
This report highlights relevant concepts related to the toxicology of genotypically brown sorghums (GBS), emphasizing aspects related to their intrinsic and extrinsic toxicities.
Figure 1. Sorghum grain and testa.
TOXICOLOGY OF GENOTYPICALLY BROWN GRAIN SORGHUMS
The GBS designation is given by the presence of a defined layer of cells called the testa (Rooney and Miller, 1981; Rumbos, 1986). This layer is present and highly pigmented in the initial grain formation stage.
As a highly significant structural characteristic, it has been determined that GBSs with a highly developed and highly pigmented testa have high total polyphenol and CT contents compared to those with little or no development of this layer (Doherty et al., 1987; Ciccola, 1989).
This fact suggests that it is in this layer where the cells that produce these compounds are located. Therefore, those cultivars that do not have a testa (genotypically white sorghums) do not contain CT; their nutritional value is around 96-98% in relationship with corn (Sullivan, 1987).
Intrinsic Toxicity: Polyphenolic Compounds
From a chemical point of view, polyphenolic compounds can be classified into three groups:
Phenolic acids are found in all sorghum cultivars and the vast majority of flavonoid compounds, while tannins, particularly condensed ones, are present only in GBS, possessing a pigmented testa, resistant to bird attack and enzymatic degradation (Hahn et al., 1984).
Tannins
Tannins ar...
