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Purina Nutrition Exchange: July 2021

Michael R. Lappin, DVM, PhD, DACVIM, Kenneth W. Smith Professor in Small Animal Clinical Veterinary Medicine, Colorado State University

Jason Gagné, DVM, DACVN, Director, Veterinary Technical Communications Nestlé Purina PetCare

Ragen T.S. McGowan, PhD, Research Scientist Nestlé Purina Research St. Joseph, Missouri


Sponsored by Nestlé Purina Company

Colorado State University Study Evaluates Probiotic for Calming Effects in Cats

Michael Lappin, DVM, PhD, DACVIM (SAIM)

The probiotic Bifidobacterium longum BL999 was the focus of a recent feline study conducted at Colorado State University (CSU) in partnership with Purina scientists.¹ What was the purpose of this research?

The probiotic BL999, which is in Purina® Pro Plan® Veterinary Supplements Calming Care canine probiotic supplement, is indicated for use in helping dogs maintain calm behavior. The purpose of this study was to examine the probiotic’s effects in purpose-bred research cats with chronic feline herpesvirus 1 (FHV-1) infection. Our primary hypotheses were that cats supplemented with BL999 would have higher relaxation scores, lower stress markers and lower clinical scores for reactivated FHV-1 than cats supplemented with a placebo when placed under mild stress.

How was the study conducted?

To test these hypotheses, a 12-week study was designed using cats with chronic subclinical FHV-1 infection, a common infection of cats in which clinical disease can be exacerbated by stress. We enrolled 24 cats with FHV-1 that were randomly divided into placebo and BL999 groups, and cats were supplemented with either BL999 or a placebo in 15 grams of canned cat food. Because we estimated that it would take up to a maximum of six weeks for cats to reach the maximal benefits from the probiotic, the study was conducted in two phases.

For the first 42 days, the cats were housed by supplement type in two separate group housing rooms with similar enrichment. During the second 42 days using two-week intervals, the cats were twice moved back and forth from the respective group housing room into individual cages for the purpose of inducing mild stress.

During this period, biochemical, clinical and behavioral markers were measured. Cats received their assigned dietary supplement during both phases of the study.

What were the study findings¹?

All cats ate all or a majority of both supplements, and there was no obvious vomiting or diarrhea. We noted statistically significant findings in all three types of markers during the second half of the study, when mild stress was induced.

  • Biochemical changes: During the stress periods, the cats supplemented with BL999 were significantly less likely to have abnormal serum cortisol concentrations (P = 0.0059).
  • Clinical changes: During the stress periods, the cats supplemented with BL999 were significantly less likely to exhibit sneezing (p = 0.0001).
  • Behavioral changes: During the times cats were housed in cages, those supplemented with BL999 were significantly more likely (p < 0.0001) to reach out to the scorers through the cage bars and significantly less likely (p < 0.0003) to pace in the cages.

What can veterinary practitioners take away from this study?

The results of the CSU study suggest that BL999, the probiotic in Calming Care, is well tolerated by cats, reduces stress, reduces stress-associated problems like reactivated FHV-1, and increases social interactions between cats and people.

Reference & Author Information

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