Two probiotic strains affect pig fat and meat quality in opposite ways.

Farmers want better ways to manage animal fat and meat quality, but scientists do not fully understand how different beneficial gut bacteria, called probiotics, compare. Researchers tested this by feeding heavy finishing pigs two different bacterial strains: Lactobacillus reuteri and Lactobacillus johnsonii. Both bacteria lowered stress hormones and inflammation while raising antioxidant defenses. However, each strain worked differently inside the body. Lactobacillus johnsonii turned on a biological switch called the AMPK/PPARγ signaling pathway. This pathway speeds up the breakdown of fat and slows fat production. As a result, pigs eating this strain had smaller fat cells and thinner backfat. In contrast, Lactobacillus reuteri did not focus on overall fat reduction. Instead, it improved meat quality traits. It made the pork more tender, lowered intramuscular fat, and raised levels of specific amino acids, which are the building blocks of protein. The results show that different strains do distinct jobs.

Why it matters

Pork producers can now choose specific probiotics to either reduce backfat or improve meat tenderness. This means more efficient production of lean pork or higher-quality pork for consumers. The study shows that not all probiotics work the same way, so targeted use can save costs and improve outcomes.

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