Microbial Diversity and Organic Acid Production of Guinea Pig Faecal Samples

Probiotic capacity of commensal lactic acid bacteria from the intestine of Guinea pigs (Cavia porcellus)

The intricate balance of intestinal microbiota is significantly influenced by the pivotal role of indigenous lactic acid bacteria (LAB). These LAB not only contribute to antimicrobial activity and enhance animal health and productivity but also serve as defense against intestinal infections. In the present study, the probiotic potential of LAB strains isolated from various intestinal sections of adult and young guinea pigs (Cavia porcellus) was comprehensively assessed. Strains belonging to the genera Ligilactobacillus, Weissella, Enterococcus, and Limosilactobacillus were also identified. The antibacterial activities of the LAB strains against Salmonella typhimurium, Escherichia coli, and Staphylococcus aureus were quantified. Exopolysaccharide production, adherence capacity, antibiotic resistance, and bile salt tolerance (0.15 %, 0.30 %, and 0.45 %) of LAB were quantified. Further analyses focused on the effects of pH (2.9, 5.0, 6.4, and 7.4), temperature (40, 50, and 60 °C) and NaCl concentrations (3.5 % and 6.5 % w/v) on LAB growth. Strains GCI9 and GDE10 (Ligilactobacillus salivarius), isolated from the cecum and intestine of guinea pigs, exhibited significant antimicrobial activity against S. typhimurium, E. coli and S. aureus. Remarkable adherence capacity to porcine gastric mucin was demonstrated by L. salivarius strains, specifically ACI1, GCI9, and GDE10, with the highest exopolysaccharide levels produced by ACI1 and GCI9 (1.71 and 1.76 mg/mL, respectively). The probiotic potential was further underscored by remarkable bile salt tolerance, especially in strain GDE10, and substantial exopolysaccharide production. These strains displayed notable adaptability to varying environmental conditions, including NaCl concentrations at 3.5 % and 6.5 %, temperatures ranging from 40 to 60 °C, and pH levels of 2.9, 5.0, 6.4, and 7.4. This comprehensive assessment of the probiotic properties of L. salivarius strains, particularly ACI1, GCI9, and GDE10, shows promise for the development of probiotic formulations aimed at enhancing the intestinal health of guinea pigs.

Genomic characterization and probiotic potential of lactic acid bacteria isolated from feces of guinea pig (Cavia porcellus)

Background

Presently, there exists a growing interest in mitigating the utilization of antibiotics in response to the challenges emanating from their usage in livestock. A viable alternative strategy encompasses the introduction of live microorganisms recognized as probiotics, exerting advantageous impacts on the immune system and nutritional aspects of the host animals. Native lactic acid bacteria, inherently possessing specific properties and adaptive capabilities tailored to each animal, are deemed optimal contenders for probiotic advancement.

Aim

In the current investigation, microorganisms exhibiting probiotic potential were isolated, characterized, and identified from the fecal samples of guinea pigs (Cavia porcellus) belonging to the Peruvian breed.

Methods

The lactic acid bacteria isolated on Man, Rogosa, and Sharpe agar underwent Gram staining, catalase testing, proteolytic, amylolytic, and cellulolytic activity assays, low pH tolerance assessment, hemolytic evaluation, antagonism against Salmonella sp., determination of autoaggregation and coaggregation capacity, and genotypic characterization through sequencing of the 16S rRNA gene.

Results

A total of 33 lactic acid bacteria were isolated from the feces of 30 guinea pigs, also 10 isolates were selected based on Gram staining and catalase testing. All strains exhibited proteolytic activity, while only one demonstrated amylolytic capability, and none displayed cellulase activity. These bacteria showed higher tolerance to pH 5.0 and, to a lesser extent, to pH 4.0. Furthermore, they exhibited antagonistic activity against Salmonella sp. Only two bacteria demonstrated hemolytic activity, and were subsequently excluded from further evaluations. Subsequent assessments revealed autoaggregation capacities ranging from 4.55% to 23.19%, with a lesser degree of coaggregation with Salmonella sp. ranging from 3.53% to 8.94% for the remaining eight bacterial isolates. Based on these comprehensive tests, five bacteria with notable probiotic potential were identified by molecular assays as Leuconostoc citreum, Enterococcus gallinarum, Exiguobacterium sp., and Lactococcus lactis.

Conclusion

The identified bacteria stand out as promising probiotic candidates, deserving further assessment in Peruvian breed guinea pigs. This exploration aims to enhance production outcomes while mitigating the adverse effects induced by pathogenic microorganisms.

Comparative analysis of fasting effects on the cecum microbiome in three guinea pig breeds: Andina, Inti, and Peru

Guinea pigs have historically been used as a food source and are also an important model for studying the human intestines. Fasting is the act of temporarily stopping the intake of food. This process can alter the microbiota of various animals. This study is the first to investigate the impact of fasting on the cecum microbiome of three guinea pig breeds. We investigated the impact of fasting on the microbiome population structure in the cecum of three guinea pig breeds. This was done by sequencing and analyzing the V4 hypervariable region of the 16S rRNA gene in bacterial communities found in cecum mucosa samples. To achieve this, we established two treatment groups (fasting and fed), for each of the three guinea pig breeds: Andina, Inti, and Peru. The study involved twenty-eight guinea pigs, which were divided into the following groups: Andina-fed (five), Andina-fasting (five), Inti-fed (four), Inti-fasting (five), Peru-fed (five), and Peru-fasting (four). The results indicated a significant difference in beta diversity between the treatment groups for the Peru breed (P-value = 0.049), but not for the treatment groups of the Andina and Inti breeds. The dominant phyla across all groups were Firmicutes and Bacteroidetes. We observed variations in the abundance of different taxa in the cecum microbiota when comparing the treatment groups for each breed. Additionally, there was a higher number of unique taxa observed in the fasting groups compared to the fed groups. We discovered that the genus Victivallis was the only one present in all fasting groups across all breeds. Despite the findings, the resilience of the gut microbiome was not challenged in all three breeds, which can lead to disruptive changes that may affect the overall maintenance of the cecum microbiome. Based on the observed differences in the treatment groups of the Peru breed, it can be suggested that fasting has a greater impact on this particular breed.

An analysis of the cecum microbiome of three breeds of the guinea pig: Andina, Inti, and Peru

This study investigated the effect of host genetics on the structure and composition of the cecum microbiota of three breeds of guinea pigs: Andina, Inti, and Peru. Fifteen guinea pigs were distributed into three groups according to their breed: Andina (5), Inti (5), and Peru (5). We discovered that four main phyla were shared between the three breeds: Bacteroidota, Firmicutes, Spirochaetota, and Synergistota. Although there were no significant differences in the alpha and beta diversity analysis, we found that the Linear discriminant analysis effect size and the heat tree analysis showed significant differences between the abundance of several taxa present in the cecum microbiome of the three breeds. These results suggest that host genetics could be a factor in the structure and composition of the guinea pig cecum microbiome. In addition, we found unique genera for each breed that have fermentation capacity and, therefore can be analyzed in further studies to determine if there is a functional relationship between them and the breed and its industrial profile.