Characterization of Lactobacillus rhamnosus MP01 and Lactobacillus plantarum MP02 and Assessment of Their Potential for the Prevention of Gastrointestinal Infections in an Experimental Canine Model

Abstract

The aim of the present study was to evaluate the probiotic potential of Lactobacillus rhamnosus MP01 and Lactobacillus plantarum MP02, two strains isolated from canine milk. These two isolates were characterized in vitro for their survival to conditions similar to those found in the canine gastrointestinal tract, production of antimicrobial compounds, adherence to intestinal mucin, degradation of mucin, and antibiotic sensitivity. Globally, both strains exhibited a high in vitro probiotic potential. Finally, their potential for the prevention of gastrointestinal infections was evaluated in an experimental canine model using 1-month-old puppies. A group of 12 German shepherd puppies, 6 males and 6 females, received L. rhamnosus MP01 daily for 2 months and a second group of 12 puppies, 6 males and 6 females, of the same breed received L. plantarum MP02 during the same period of time. The same experimental approach was carried with Yorkshire puppies. Additionally, the trial included 12 dogs of each breed in the placebo groups. The results demonstrated that administration of the strains resulted in a significant preventive effect of gastrointestinal infections in such populations.

Keywords: Lactobacillus plantarum; Lactobacillus rhamnosus; dog; gastroenteritis; prevention; probiotics.

FIGURE 1

Weight gain (kg) in participant German shepherd and Yorkshire puppies at the end of the assay. C, control group; LP, group supplemented with L. plantarum MP02; LR, group supplemented with L. rhamnosus MP01.

FIGURE 2

Gastrointestinal infection (GI) episodes registered for German shepherd and Yorkshire puppies during the first 4 weeks (weeks 5–8) and the last 4 weeks (weeks 9–12) of the assay, and the total number of episodes (weeks 5–12), in the control (C), L. plantarum MP02 (LP) and L. rhamnosus MP01 (LR) groups. There were statistically significant differences in the number of GI episodes registered during the last 4 weeks of the assay among the three groups (C, LP, and LR) for both breeds (one-way ANOVA). The letters above the bars indicate the statistically significant differences among the groups (Tukey’s HSD tests).

FIGURE 3

Clinical evolution of German shepherd and Yorkshire puppies during the assay. (A) Change in the number of gastrointestinal infection (GI) episodes registered for each puppy during the last four weeks of the assay (weeks 9–12 of age) with respect to the number of GI episodes recorded during the first four weeks of the assay (weeks 5–8 of age) in the control group (C, white), in the L. plantarum MP02 group (LP, light grey) and in the L. rhamnosus MP01 group (LR, deep gray). (B) Global change in the number of GI episodes in the three study groups (C, control group; LP, group supplemented with L. plantarum MP02; LR, group supplemented with L. rhamnosus MP01).

FIGURE 4

Fecal bacterial counts in German shepherd and Yorkshire puppies at the beginning (week 5) and at the end (week 12) of the assay in the control (C), L. plantarum MP02 (LP) and L. rhamnosus MP01 (LR) groups. Lactobacillus and Enterobacteraceae counts were determined by conventional plating and Faecalibacterium content was estimated by quantitative real time-PCR. ^∗p < 0.050; ^∗∗∗p < 0.001 (one-way ANOVA).

FIGURE 5

IgA content (μg/μg TP) in feces of German shepherd and Yorkshire female (F) and male (M) puppies at the beginning (week 5, light blue) and at the end (week 12; dark blue) of the assay in the control (C), L. plantarum MP02 (LP) and L. rhamnosus MP01 (LR) groups. Paired t-tests were performed to analyze if the individual change in the concentration of IgA at the end of the assay was statistically significant in each group of dogs.

FIGURE 6

Fecal SCFAs (acetate, propionate, and butyrate) content (mg/g) in feces of German shepherd and Yorkshire puppies at the beginning (week 5) and at the end (week 12) of the assay in the control (C), L. plantarum MP02 (LP) and L. rhamnosus MP01 (LR) groups. Paired t-tests were performed to analyze if the individual change in the concentration of individual SCFAs at the end of the assay was statistically significant for each group of dogs.