Probiotic potential of Weissella strains isolated from horse feces

In this study, we isolated four Weissella confusa strains from the healthy horse feces to test their potential as equine probiotics. The identification and characteristics of these isolates were determined as per standard methods. Resistance and susceptibility of the isolated strains were tested to low pHs, different heat treatments, commonly used antibiotics and against the pathogenic strains of Salmonella, Pasteurella, Staphylococcus aureus, and Escherichia coli. After 3 h cultural in different pH medium, the 4 strains still had a certain amount of survival above pH 3.0. WH2 and WH4 were still viable at pH2.5. All the isolated strains showed proper growth at 60 degrees C while no strain survived at 80 degrees C. The inhibition of alpha-amylase, the scavenging ability of free radical DPPH center dot and hydroxyl free radical HO center dot were also investigated. The results showed that WH4 had highest inhibition rate of alpha-amylase activity and DPPH center dot free radical scavenging rate, and the inhibition rate of alpha-amylase activity was 24.09% and the DPPH center dot free radical scavenging rate was 35.78%. The inhibition rate of alpha-amylase activity and DPPH center dot scavenging rate of free radicals in the other three strains were about 10%. The clearance rate of hydroxyl radical (HO center dot) in 4 strains was between 12% and 15%. The antibiotic susceptibilities varied for these four Weisella strains but all of them showed resistance against the frequently used equine antibiotics. All the four strains successfully suppressed the growth of standard strains in in vitro bacteriostasis experiment, which included Salmonella enteritidis (NTNC13349), Escherichia coli (C83902) and Staphylococcus aureus (BNCC186335). they also successfully suppressed the growth of state key laboratory isolating pathogens, which are Pasterurella multocida and Salmonella. Our findings suggest that the isolated strains of Weissella confusa can act as potential equine probiotics and should be explored further.