Feeding distillers grains to cattle may affect beef tenderness early postmortem

Area of Science:

• Animal Science
• Food Science
• Biochemistry

Background:

• Dietary fat sources significantly influence meat quality traits, including beef tenderness.
• Modified distillers grains plus solubles (MDGS) are a byproduct of grain processing, increasingly used in cattle diets.
• Understanding the impact of MDGS on beef tenderness mechanisms is crucial for optimizing production.

Purpose of the Study:

• To investigate the effects of dietary fat source, specifically MDGS inclusion, on beef tenderness.
• To examine the underlying mechanisms involving sarcoplasmic reticulum (SR) membrane fatty acid composition and sarcoplasmic calcium concentration.
• To assess Warner-Bratzler shear force (WBSF), sarcomere length, and proteolysis postmortem.

Main Methods:

• Feeding 256 steers diets with varying levels of MDGS or corn for 134 days.
• Analyzing SR membrane fatty acid profiles, sarcoplasmic calcium concentration, WBSF, sarcomere length, and troponin-T degradation.
• Aging strip loins for 2-23 days postmortem and subjecting them to 7 days of retail display.

Main Results:

• MDGS-fed cattle exhibited increased linoleic acid (18:2) and tended to have higher total polyunsaturated fatty acids (PUFA) in the SR membrane.
• Higher sarcoplasmic calcium concentrations were observed in steaks from MDGS-fed cattle at 2 days postmortem.
• Tendencies towards lower WBSF values were noted in steaks from cattle fed de-oiled MDGS diets, suggesting improved tenderness.

Conclusions:

• Dietary MDGS inclusion may enhance beef tenderness by increasing SR membrane PUFA, leading to greater postmortem calcium release.
• This calcium release could be a key factor in improving early postmortem beef tenderness.
• Further research can explore optimizing MDGS inclusion for consistent tenderness improvements.