RESUMO
The use of bifidobacteria as probiotics has proven to be beneficial in gastroenteric infections. Furthermore, prebiotics such as inulin can enhance the survival and growth of these bacteria. Two trials were performed to evaluate the effects of the administration of Bifidobacterium longum subsp. infantis CECT 7210 and oligofructose-enriched inulin against Salmonella enterica serovar Typhimurium or enterotoxigenic Escherichia coli (ETEC) F4. A total of 72 (Salmonella trial) and 96 (ETEC F4 trial) weaned piglets were used in a 2 × 2 design (with or without synbiotic, inoculated or not with the pathogen). After adaptation, animals were orally inoculated. Performance and clinical signs were evaluated. On days 4 and 8 (Salmonella trial) and 3 and 7 (ETEC F4 trial) post-inoculation (PI), one animal per pen was euthanized. Blood, digestive content and tissue samples were collected and microbiological counts, fermentation products, serum inflammatory markers and ileum histomorphometry analysis were performed. Both challenges had an impact on faecal consistency (p < 0.001), including the faecal shedding of Salmonella and increased numbers of enterobacteria and coliforms. The synbiotic administration did not have any effect on pathogen loads but induced changes in the fermentation profile, such as increased valeric acid in both trials as well as decreased acetic acid, except for Salmonella-challenged animals. The effect on propionate varied among trials, increasing in challenged synbiotic-treated pigs and decreasing in non-challenged ones in the Salmonella trial (P interaction = 0.013), while the opposed occurred in the ETEC F4 trial (P interaction = 0.013). The administration of the synbiotic increased intraepithelial lymphocytes (IEL; p = 0.039) on day 8 PI in the Salmonella trial and a similar trend occurred in non-challenged pigs in the ETEC F4 trial (P interaction = 0.086). The results did not provide evidence of reduced pathogen load with the synbiotic, although a modulation in fermentative activity could be identified depending on the challenge. Consistent increases were found in IEL, suggesting that this synbiotic combination has some immunomodulatory properties.
RESUMO
We evaluated the potential of multi-strain probiotic (Bifidobacterium longum subsp. infantis CECT 7210 and Lactobacillus rhamnosus HN001) with or without galacto-oligosaccharides against enterotoxigenic Escherichia coli (ETEC) F4 infection in post-weaning pigs. Ninety-six piglets were distributed into 32 pens assigned to five treatments: one non-challenged (CTR+) and four challenged: control diet (CTR-), with probiotics (>3 × 1010 CFU/kg body weight each, PRO), prebiotic (5%, PRE), or their combination (SYN). After 1 week, animals were orally inoculated with ETEC F4. Feed intake, weight, and clinical signs were recorded. On days 4 and 8 post-inoculation (PI), one animal per pen was euthanized and samples from blood, digesta, and tissues collected. Microbiological counts, ETEC F4 real-time PCR (qPCR) quantification, fermentation products, serum biomarkers, ileal histomorphometry, and genotype for mucin 4 (MUC4) polymorphism were determined. Animals in the PRO group had similar enterobacteria and coliform numbers to the CTR+ group, and the ETEC F4 prevalence, the number of mitotic cells at day 4 PI, and villus height at day 8 PI were between that observed in the CTR+ and CTR- groups. The PRO group exhibited reduced pig major acute-phase protein (Pig-MAP) levels on day 4 PI. The PRE diet group presented similar reductions in ETEC F4 and Pig-MAP, but there was no effect on microbial groups. The SYN group showed reduced fecal enterobacteria and coliform counts after the adaptation week but, after the inoculation, the SYN group showed lower performance and more animals with high ETEC F4 counts at day 8 PI. SYN treatment modified the colonic fermentation differently depending on the MUC4 polymorphism. These results confirm the potential of the probiotic strains and the prebiotic to fight ETEC F4, but do not show any synergy when administered together, at least in this animal model.
RESUMO
Salmonella is a common causative agent of enteric disease and is developing mechanisms of resistance to antimicrobials. Probiotics, such as bifidobacteria and lactobacilli, and prebiotic fibers are a potential alternative to counteract this pathogen as they have demonstrated effectiveness in preventing its adhesion, reducing intestinal damage, and enhancing the host immune system. Furthermore, the benefits are expected to be potentiated when these compounds are administered together. A trial was performed to evaluate the efficacy of two probiotic strains (Bifidobacterium longum subsp. infantis CECT 7210 (Laboratorios Ordesa S.L.) and Lactobacillus rhamnosus HN001, combined or not with a prebiotic containing oligofructose-enriched inulin, against Salmonella Typhimurium. Ninety-six piglets (28 days old) were distributed into 32 pens assigned to 5 treatments: one non-challenged (control diet, CTR+) and four challenged: control diet (CTR-) or supplemented with probiotics (>3 × 1010 cfu/kg each strain, PRO), prebiotic (5%, PRE), or their combination (SYN). After 1 week of adaptation, animals were orally challenged with Salmonella Typhimurium. Feed intake, weight, and clinical signs were recorded. On days 4 and 8 post-inoculation (PI), one animal per pen was euthanized, and samples from blood, digestive content, and ileal tissues were collected to determine Salmonella counts, fermentation products, ileal histomorphology, and serum TNF-α and Pig-MAP concentrations. The effect of the oral challenge was evidenced by animal performance, fecal consistency, and intestinal architecture. Regarding the experimental treatments, animals belonging to the PRO group experienced a faster clearance of the pathogen, with more pigs being negative to its excretion at the end of the study and recovering the impaired ileal villi/crypt ratio more rapidly. Animals receiving the PRE diet showed a lower intestinal colonization by Salmonella, with no countable levels (<3 cfu/g) in any of the analyzed samples, and an augmented immune response suggested by serum Pig-MAP concentrations. Treatments including the prebiotic (PRE and SYN) showed similar changes in the fermentation pattern, with an increase in the molar percentage of valeric acid concentration in the colon. The SYN group, however, did not show any of the outcomes registered for PRO and PRE in Salmonella colonization or in immunity markers, suggesting the lack of synbiotic action in this animal model. Further research is needed to better understand the complex mechanisms behind these effects.
RESUMO
Probiotics have been demonstrated to be useful to enhance gut health and prevent gastrointestinal infections in humans. Additionally, some multi-strain probiotic combinations have been suggested to have greater efficacy than single strains. The objective of this study is to demonstrate the potential of a combination of the probiotic strains: Bifidobacterium longum subsp. infantis CECT 7210 (brand name B. infantis IM1®) and B. animalis subsp. lactis BPL6 to enhance gut health and to ameliorate the outcome of a Salmonella challenge using a weaning piglet model. Seventy-two 28-day-old weanling piglets, 7.7 (±0.28) kg of body-weight, were distributed in a 2 × 2 factorial design; treated or not with the probiotic combination and challenged or not with the pathogen. Animals were orally challenged after an adaptation period (Day 8) with a single dose (5 × 108 cfu) of Salmonella Typhimurium. One animal per pen was euthanized on Day 12 (Day 4 post-inoculation [PI]) and Day 16 (Day 8 PI). All parameters responded to the challenge and 4 deaths were registered, indicating a severe but self-limiting challenge. Improvements registered in the challenged animals due to the probiotic were: increased voluntary feed-intake (P probiotic × challenge = 0.078), reduced fecal excretion of Salmonella (P = 0.028 at Day 1 PI and P < 0.10 at Days 3 and 5 PI), decreased rectal temperature (P probiotic × day = 0.048) and improvements in the villous:crypt ratio (P probiotic × challenge < 0.001). Moreover, general probiotic benefits were observed in both challenged and non-challenged groups: decreased diarrhea scores of the PI period (P = 0.014), improved fermentation profiles on Day 8 PI (increased ileal acetic acid [P = 0.008] and a tendency to lower colonic ammonia concentrations [P = 0.078]), stimulation of intestinal immune response by increasing villous intraepithelial lymphocytes (P = 0.015 on Day 8 PI) and an improved villous:crypt ratio (P = 0.011). In conclusion, the multi-strain probiotic had a positive effect on reducing pathogen loads and alleviating animals in a Salmonella challenge. In addition, enhanced gut health and immunity was recorded in all animals receiving the probiotic, indicating an improvement in the post-weaning outcome.
