Effects of lactic acid bacteria on metritis prevalence and endometrium inflammation in dairy cows

Abstract Text:

The aim of this study was to evaluate the effects of a treatment with Lactobacillus rhamnosus, Pediococcus acidilactici, and Lactobacillus reuteri (LAB) on the prevalence of metritis and the modulation of endometrial inflammation in dairy cows. In experiment 1, 135 cows were enrolled 3 wk before calving and randomly assigned to treatments to insure similar frequencies for parity and previous illness in all treatment groups. The treatment groups were: (1) two intravaginal doses of lactic acid bacteria (LAB) per wk during 3 wk pre-calving (Vaginal); (2) 1 intra-uterine dose 1 d after calving (Endometrial); and (3) no intervention (Control). Metritis was diagnosed at d 6 when body temperature >39.5° C and purulent vaginal discharge (>50% pus or worse) was observed. Data were analyzed using a chi-square. Vaginal treatment reduced (P < 0.05) metritis prevalence up to 62% compared with the Control group. However, prevalence of metritis did not differ between the Endometrial and Control group. In experiment 2, a combination of in vivo and ex vivo assays to evaluate whether LAB exerted some effects on the endometrium was designed. Twenty healthy do-no-breed cows were enrolled in experiment 2, 3 wk before culling were randomly distributed into 2 treatment groups: (1) 2 doses of vaginal LAB per wk during 3 wk (LAB); and (2) 2 vaginal doses of carrier (sterile sodium chloride 0.9%) per wk during 3 wk (CTRL). Endometrium was recovered at slaughterhouse and cut in the laboratory in 0.8 cm² explants that were incubated by sixtiplicate in 24 well-plates and either infected with Escherichia coli or maintained in medium for evaluating the basal expression of pro-inflammatory genes in the endometrium. Supernatant was collected for IL-8, IL-1β, and IL-6 analysis by ELISA. Explants were recovered for the quantification of pro-inflammatory gene expression by qPCR. Data were analyzed using an ANOVA, considering treatment and infection as fixed effects and animal as a random effect. Neither the expression of pro-inflammatory genes nor the direct quantification of IL-8, IL-1b, or Il-6 differed between infected and non-infected explants. In conclusion, when an intravaginal treatment of LAB is applied there is an important reduction on metritis prevalence although this reduction is not mediated by a direct effect the probiotic on the endometrium neither by increasing the protection against E. coli nor by reducing basal inflammation. 

Keywords:

Escherichia coli, LAB, metritis.