Overview.
What it is. Lactobacillus acidophilus is a rod-shaped, lactic-acid-producing bacterium that lives naturally in the small intestine of mammals. Acidophilus means "acid-loving" — it thrives in the acidic upper gut, which is why it survives where many other probiotics do not. The NCFM strain was first isolated at North Carolina State University and has been in commercial probiotic products since the 1970s.
How it works. L. acidophilus ferments sugars into lactic acid and small amounts of hydrogen peroxide. The acid environment makes it harder for pathogenic bacteria to grow and bind to the gut wall. The strain also produces bacteriocins, which are tiny antimicrobial peptides that selectively kill harmful bacteria while sparing beneficial ones. Together these effects shift the gut ecology toward a healthier balance.
Typical dose for dogs.
Small dogs (under 25 lbs): 1 billion CFU per day
Medium dogs (25–50 lbs): 2-3 billion CFU per day
Large dogs (50+ lbs): 3-5 billion CFU per day
Safety: L. acidophilus has been used safely in human and animal supplements for over fifty years. Side effects are limited to mild gas in the first few days. Avoid in dogs with severe immune compromise without a vet check.
The classic gut workhorse
L. acidophilus is the strain that most people picture when they hear the word probiotic, and for good reason. It has the longest commercial track record and the broadest body of supporting research. Saggioro showed in 2004 that acidophilus supplementation improved abdominal discomfort and stool consistency in adults with IBS-pattern symptoms. In dogs, similar effects have been observed in trials of acidophilus-containing blends used during diet transitions and antibiotic recovery.
Lactose intolerance and dogs
Many adult dogs have low levels of lactase, the enzyme that digests milk sugar. L. acidophilus produces beta-galactosidase, an enzyme that breaks down lactose in the gut. This is one reason yogurt is sometimes tolerated by dogs even when straight milk is not — the live acidophilus pre-digests some of the lactose. A probiotic supplement gives the same enzyme support in a more predictable dose.
Why blends usually beat single strains
Single-strain acidophilus products were the standard in the 1980s and 1990s. Modern research has shifted toward multi-strain blends because different strains colonize different parts of the gut and serve different functions. Acidophilus excels in the small intestine. Bifidobacteria thrive in the colon. Bacillus coagulans survives transit best. Together they cover more ground than any one strain alone.
In our line.
Found in PawBite products: Daily Probiotic.