We previously isolated the commensal bacteria lactobacilli and bifidobacteria from the Thoroughbred intestine and prepared the horse probiotics LacFiTM, consisting of Lactobacillus ruminis KK14, L. equi KK 15, L. reuteri KK18, L. johnsonii KK21, and Bifidobacterium boum HU. Here, we found that the five LacFiTM constituent strains remarkably suppressed pro-inflammatory interleukin-17 production in mouse splenocytes stimulated with interleukin-6 and transforming growth factor-β. The protective effects of the probiotic on impaired intestinal barrier function were evaluated in Caco-2 cells treated with tumor necrosis factor-α. Evaluation of transepithelial resistance showed that all the strains exhibited intestinal barrier protective activity, with significant suppression of barrier impairment by L. reuteri KK18. The LacFiTM constituent strains were detected in neonatal LacFiTM-administered Thoroughbred feces using polymerase chain reaction denaturing gradient gel electrophoresis and culture methods. These five strains were found to be the predominant lactobacilli and bifidobacteria in the intestinal microbiota of LacFiTM-administered Thoroughbreds. Administration of LacFiTM to neonatal Thoroughbreds decreased diarrhea incidence from 75.9% in the control group (n=29 neonatal Thoroughbreds) to 30.7% in the LacFiTM-administered group (n=101 neonatal Thoroughbreds) immediately after birth to 20 weeks after birth. LacFiTM treatment also prevented diarrhea especially at and around 4 weeks and from 10 to 16 weeks. The duration of diarrhea was also shorter in the probiotics-administered group (7.4 ± 0.8 days) than in the control group (14.0 ± 3.2 days). These results indicate that the LacFiTM probiotics regulates intestinal function and contributes to diarrhea prevention.

A male Thoroughbred fetus was aborted on day 251 of pregnancy. Gross and histological examinations detected systemic granulomatous lesions in many superficial and visceral lymph nodes and organs including the liver, tonsils, lungs, thymus, spleen, right thyroid gland and gastrointestinal tract, and suppurative placentitis, pyogranulomatous amnionitis and intralesional acid-fast bacilli were also detected. An examination of the DNA base sequence of the β subunit of RNA polymerase demonstrated that Mycobacterium avium strain 104 had infected several organs. To the best of our knowledge, this is the first report of equine fetal mycobacterial infection in Japan.

Back pain is a common clinical condition that leads to poor performance in racehorses. Therefore, horse owners would benefit from a suitable and effective treatment that results in the early recovery of their horses. Dermal suctioning significantly improves chronic lower back pain in humans. Thus, if a similar effect were to be found in racehorses, it could become a new treatment for back pain in horses. In this study, we examined the acute effects of dermal suctioning on back pain in racehorses. Twelve Thoroughbred racehorses with back pain underwent 10 min of dermal suctioning in the thoracolumbar region. The pain score, mechanical nociceptive threshold (MNT), heart rate variability (HRV), and plasma cortisol concentrations were measured. Results showed that pain scores were significantly improved immediately after dermal suctioning (P=0.028), while MNT, HRV, and plasma cortisol concentrations did not show significant changes (P>0.05). These results indicate that dermal suctioning immediately relieves pain but has a limited effect on the other three parameters.