Could the pale, soft, and exudative condition be explained by distinctive histological characteristics?

Area of Science:

• Animal Science
• Meat Science
• Histology

Background:

• Pork quality is influenced by genetic and environmental factors.
• Pale, Soft, Exudative (PSE) pork remains a significant concern despite improved slaughter conditions.
• Understanding muscle characteristics related to PSE pork is crucial for the industry.

Purpose of the Study:

• To evaluate tissue characteristics of stress-susceptible muscles compared to a reference muscle in pigs with different HAL and RN genotypes.
• To identify histological markers associated with PSE pork development.
• To define and validate a PSE index.

Main Methods:

• Histology, histoenzymology, and immunohistochemistry were used.
• Muscle samples (M. triceps brachii, M. longissimus dorsi, M. biceps femoris, M. semimembranosus) were analyzed.
• Pigs with specific HAL (NN, Nn, nn) and RN (rn+rn+, rn+RN-) genotypes were studied.

Main Results:

• A combination of high type IIb fiber count and low vascularization significantly impacts muscles prone to stress.
• A novel PSE index was developed, showing a dramatic increase in muscles associated with PSE conditions (P < 0.001).
• Distinct histological characteristics were linked to muscle vulnerability, independent of genotype, suggesting potential genotype interactions.

Conclusions:

• Specific histological features contribute to muscle vulnerability to PSE conditions.
• The developed PSE index effectively identifies muscles prone to PSE pork.
• Genotype influences muscle histology, and interactions between genotypes may affect pork quality.