Evaluation of Microsatellite Set to Trace Aberdeen Angus Beef from Argentine

ROGBERG-MUÑOZ A; PRANDO A; SILVA MELLO CESAR A; LIRÓN J. P.; SORARRAIN N.; RAMELLI P.; POSIK D.M.; POFCHER E.; RIPOLI M. V.; BERETTA E.; MARIANI P.; BALDO A.; GIOVAMBATTISTA G.

Torremolinos, Spain

Conferencia; TRACE 4th Annual Meeting and Conference; 2008

TRACE

Traceability is essential to guarantee the origin of meat; this is supported by the use of identification labels attached to live animals and meat products throughout the production and commercialization chain. In 2006, MERCOSUR exported about 40% of the world beef and cattle commercialized, and produced 9% of the world’s milk. Argentinean beef is well known for its quality (tenderness and flavour) and for being natural (pasture feeding system). Angus is the major beef cattle bred in Argentine.In Argentine, local legislation requires group traceability based on a double conventional ear tag, DTA form (Documento de Tránsito Animal), and slaughter identification. More accurate technologies, such as electronic identification and DNA methods, could improve traceability system guaranteeing safety and quality of beef to consumers, this would allow Argentine to supply demanding markets (e.g. EU) and get higher prices. DNA can be considered the best system for beef traceability because can be used to trace the entire production and commercialization brand, from live animals to its derived beef products. This work aim to evaluate a DNA based method as an additional control for a traceability system, in commercial herds of related and unrelated Angus from Argentine, using different kinds of samples. This study was performed on the beef production chain of Argentine Angus. All animals were identified by TypiFixTM ear tags. Samples were collected on farm (blood and ear tags samples) from 150 unrelated Angus and slaughterhouse (meat samples) from 27 related Angus. Different reported DNA extraction methods were performed for each kind of sample. Two labs, one in Argentine and the other in Italy, use eleven microsatellites for DNA genotyping of the samples. Diverse tests were curry out for statistical analysis: genetic variability, Hardy–Weinberg equilibrium, mismatch distributions among pair of samples, exclusion power, and assignment. In addition was evaluated: feasibility of used kinds of samples as DNA sources for PCR amplification; percentage of missing data; mismatches between the meat samples, blood and tags; labeling mistakes; concordance of genotypes between labs. The 97% of the extracted DNA samples were quality and quantity enough for genotyping, and only 0.2% of the markers failed to be typified. A couple of mismatches between the meat samples and tags, and one error label were detected. All microsatellites results highly polymorphic in the studied sample, with a total of 88 alleles detected (average Na = 8.00), being 87 (average Na = 7.91) and 63 (average Na = 5.73) in the unrelated and related sub-groups, respectively. The average Ho and He in the total sample were 0.68 and 0.73, respectively, ranging from 0.29 to 0.84 and from 0.65 to 0.83, respectively. There were a total of 33. Five out of 33 HWE tests (11 loci in 1 total samples and 2 sub-samples) were statistically significant (P < 0.05). Exclusion power for these level of genetic diversity, for the whole set of markers, result higher than 0,9999. Mismatch distribution showed that all animals could be distinguished with an average mismatch between pair animals of 10. Furthermore, the 100% of the individuals were correctly assigned to Angus breed either using a threshold of 0.05 or 0.01. These results evidence: (i) this microsatellite set is adequate for certifying breed, (ii) less than eleven markers can be used for routine traceability validation.