Color of meat could improve thanks to genetic combination
Identifying, for the first time, three variants of the myoglobin gene which is in charge of providing color to muscles will enable consolidating a zebu cattle improvement plan.Bogotá D. C., 14 de julio de 2016 — Agencia de Noticias UN-
The Colombian Cattle Ranching Association claims that per capita meat consumption in Colombia is 18 kilos per year.
Susan Lorena Castro, Universidad Nacional de Colombia (UNal) in Bogotá M.Sc. in Microbiology says that several environmental factors influence the color of meat such as pre and post-mortem conditions and muscle chemistry as well as other aspects such as processing, storage and maturing. However the genetic factors in cattle have been hardly researched.
Taking into account two of the most popular types of muscle (meat cuts) in the market (tenderloin and eye of round), Castro carried out a research project on the genes that impact the color features of cattle meat, specifically zebu cattle, the most prevalent breed in Colombia (of the 27 million cattle in the country at least 72% are Bos indicus).
For this the researcher visited Haciendas Cabezas and Santa Helena near the municipality of Aguachica (Province of Cesar). After analyzing 164 steer, she determined that three variables of the myoglobin gene (MB) influence not only color but also tenderness and juiciness of meat of the studied breeds.
“Although myoglobin is functionally and structurally very similar hemoglobin, one of its main functions is to store oxygen and transport it to muscles,” said Castro.
Furthermore the concentrations or deficiencies determine the red, rose, brown or purple color hues of meat.
Additionally genetic coupling from mating zebu and Bos taurus breeding bulls with Brahman cows were determinant for the results.
Cattle were divided into two groups. The first was a group of 71 progenies obtained from crossing Bos indicus and Bos indicus and bulls used were zebu Brahman (14) and Guzerat (3). The second group consisted of 93 animals product of crossing Bos taurus and Bos indicus, and bulls were Normande (3), Blanco Orejinegro (meaning: white black-eared) (3), Romosinuano (3), Braunvieh (3), Simmental (3) and Limousine (3).
When the calves reached the an average weight of 500 kilos and an age between 22 and 24 months they took samples of tenderloin and eye of round which were airtight packaged, identified and distributed in three maturation processes. Later they were stored for 7, 14 and 21 days at a temperature between 4° and 5º C (39.2° and 41° F). The UNal Food Science and Technology Institute carried out a phenotype assessment (observable traits) using a colorimeter to determine the color of the muscle sample.
A question of DNA
Another step taken was to carry out a genetic assessment and isolate DNA, specifically of the myoglobin which produces a protein with the same name. Castro discovered that variants MB5870 and MB11732 are directly related to meat color.
These variants provide characteristics regarding color as they are consistent with the colorimeter results. Furthermore they correspond to zebu female and Bos taurus male crossings which resulted better than the calves of pure zebu in their three lines.
“It is essential to identify animals which have these differences and select and include them in reproduction programs so they can mate and provide progenies with beneficial meat color features, guaranteeing red and brilliant cuts, ideal for consumers,” said Castro.
While improving color had an effect on meat tenderness it did not significantly impact it. In fact Castro not only measured this impact at the laboratory level but also with a panel formed by 15 people (amateur panelists) who classified the meat on a scale from 1 to 5 and agreed on the tenderness of the meat.
With the variability of regional climates and breeds, this research project is a support point to help the Colombian cattle industry to develop more research regarding meat quality of other cattle breeds in Colombia.(Por: FIN/HVC/DMH/APBL