Screening of Lactobacillus isolates from gastrointestinal tract of guinea fowl for probiotic qualities using in vitro tests to select species-specific probiotic candidates

Abstract

A total of 32 Lactobacillus isolates, 8 each from the crop (LGFCP1-LGFCP8), proventriculus (LGFP9-LGFP16), ileum (LGFI17-LGFI24) and caeca (LGFCM25-LGFCM32) were isolated from 25 adult guinea fowl (Pearl variety), 22-28 weeks of age, and characterised morphologically, physiologically, biochemically and by molecular methods. Isolates were screened for their probiotic quality using range of in vitro tests: aggregation test, cell surface hydrophobicity, resistance to bile salts and acidic conditions, enzymatic tests and coaggregation and antagonistic test. Based on in vitro test results and a novel scoring method, the two best isolates were selected and partial 16S rRNA sequencing was done. BLAST (Basic Local Alignment Search Tool) analysis of sequence of isolate LGFCP4 showed 99% genetic identity with Lactobacillus plantarum and LGFP16 with Lactobacillus reuteri. The study shows that these two microbial agents may be suitable as potential probiotic candidates in guinea fowl, as well as in a feed supplement for other poultry species.

Modeling lactation curve for genetic evaluation of Murrah buffaloes

“…In the present study, all these 28 isolates with short aggregation time and high hydrophobicity were selected for further screening as these properties indicated the adhesion ability to gastrointestinal tract (GIT) epithelium. Our results were in agreement with Vineetha et al (2016) from India who reported higher cell surface hydrophobicity (above 76%) for Lactobacillus isolates. Ehrmann et al (2002) reported that values higher than 66% were regarded as strong hydrophobicity.…”

“…Ehrmann et al (2002) reported that values higher than 66% were regarded as strong hydrophobicity. Resistance to low pH and bile salts is a characteristic feature of probiotic strains for survival in the GIT (Vineetha et al, 2016). A total of 20 (L2, L6, L8, L11, L12, L13, L14, L15, L16, L17, L18, L20, L26, L31, L33, L35, L36, L38, L41 and L42) out of 28 isolates showed satisfactory growth at pH 2 and 3, while other isolates showed very meager growth.…”

“…Silva et al (2013) from Brazil reported promising in-vitro antibacterial activity in Lactobacillus isolates of dog faecal origin against E. coli and other pathogenic bacteria. Vineetha et al (2016) from India reported promising in-vitro antibacterial activity in Lactobacillus isolates of poultry faecal origin against E. coli, S. typhimurium and S. enteritidis. When the pH of the Lactobacillus supernatants was adjusted to pH 7.0, reduction in antibacterial activity was noticed against all the test pathogens (Fig.…”

“…Cell surface hydrophobicity: Cell surface hydrophobicity was determined by microbial adherence to hydrocarbons (MATH) method using xylene as solvent as described by Vineetha et al (2016). Overnight grown Lactobacillus cultures were centrifuged (7500 rpm for 5 min at 4 o C), washed twice with PBS buffer and finally resuspended in the same buffer.…”

“…Overnight grown Lactobacillus cultures were kept undisturbed in Eppendorf tubes and examined after 15 min, in order to determine the degree of aggregation to the bottom of the tubes (Vineetha et al, 2016).…”