Effect of breed on biochemical traits influencing beef Longissimus tenderness

• Grant number: 12/06618-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): October 15, 2012
• Effective date (End): July 14, 2013
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Production
• Principal Investigator: Telma Teresinha Berchielli
• Grantee: Josiane Fonseca Lage
• Supervisor: Steven D. Shackelford
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Research place: U.S. Meat Animal Research Center (MARC), United States
• Associated to the scholarship: 09/18431-2 - Crude glycerine coming from the agribusiness of biodiesel in the diet of steers containing high or low level of starch in different ratios of roughage and concentrate, BP.DR

Abstract

Samples will be obtained from on-going beef breed evaluation studies at the U.S. Meat Animal Research Center. Breeds represented will include progeny of the 17 most common beef breeds in the United States. Steers (n = 1,200) will be grain-finished and harvested in commercial packing plants. Following the packing plants' routine grading procedures (i.e., at 24 to 96 h postmortem), longissimus (LM) steaks will be obtained from the anterior end of the strip loin (13th rib region). Steaks will be transported to USMARC and aged (1pC) until 14 d postmortem. Fresh (never frozen) steaks will be cooked (71pC) and slice shear force (Shackelford et al., 1999) will be measured. The remnants of the slice shear force sample (cooked LM) will be frozen (-20pC) and stored for subsequent measurement of biochemical traits influencing beef longissimus tenderness. Subsequently, 6 blocks (2 mm × 2 mm × 3 mm; 1 or 2 blocks from the center of each per half-slice remnant) will be obtained parallel to the muscle fiber orientation and 6 fibers will be teased from each block, and sarcomere length will be determined for each fiber by laser diffraction using the procedure of Cross et al. (1981). Thus, each observation for sarcomere length will represent the mean of 36 fibers. The remainder of the trimmed half-slice remnants will be diced and powdered with liquid nitrogen and postmortem proteolysis will be assessed by measuring the extent of degradation of desmin by western blotting as described by Wheeler et al. (2002). (AU)