A PRELIMINARY STUDY ON THE GUT MICROBIAL COMPOSITION OF SELECTED CARP SPECIES

Abstract

This study explored bacterial diversity in the gastrointestinal tract of the Indian Major Carp (Labeo catla) using culture-dependent techniques. Results showed notable differences in bacterial load between the foregut and hindgut. Five bacterial strains were isolated, four from the hindgut and one from the foregut. Aeromonas (CC3) was the most prevalent strain, with colony counts from 2 to 53 across plates. Morphological and Gram stain analyses identified the isolates as belonging to five genera: Serratia, Staphylococcus, Aeromonas, Bacillus, and Pseudomonas; 75% were Gram-negative, and 25% were Gram-positive. Biochemical tests revealed genus-specific traits, with Aeromonas exhibiting the widest metabolic activity, including positive reactions for citrate, urease, catalase, oxidase, and sulphur reduction. These findings offer foundational insights into the focal animal’s gut microbiota, emphasising the dominance of hindgut bacterial populations and the potential functions of certain strains.

Keywords
Catla catla, Bacterial strains, Foregut, Hindgut, Nutrient Agar