Date of Publication
4-2025
Document Type
Bachelor's Thesis
Degree Name
Bachelor of Science in Biology major in Molecular Biology and Biotechnology
Subject Categories
Biology
College
College of Science
Department/Unit
Biology
Thesis Advisor
Raymond Vincent F Castillo
Defense Panel Chair
Ma. Carmen A. Lagman
Defense Panel Member
Bienna Marie S. Joaquin
Florabelle D. Querubin
Abstract (English)
Chanos chanos, also known as Milkfish, is an economically significant aquaculture fish species in the Philippines. As a euryhaline fish, it can thrive in both freshwater and marine environments. These environments possess different environmental conditions such as salinity, pH, and temperature which could influence the gut microbiota of Chanos chanos. This study aimed to profile the gut microbiota of Milkfish reared in these environments through morphological, biochemical, and molecular analyses, including 16S rRNA gene amplification. A total of 53 bacterial isolates were obtained, with 28 from freshwater and 25 from marine cages. Morphological characterization revealed a predominance of Gram- positive bacteria (99%) with rod and cocci shapes. Biochemical assays such as catalase and indole tests showed catalase activity in most isolates (96% freshwater; 91% marine) and indole production (57% freshwater; 68% marine), indicating oxidative stress response and tryptophan degradation. Carbohydrate fermentation test results found a higher prevalence of acid and gas production in marine isolates compared to freshwater isolates. Phylogenetic analysis further revealed distinct microbial communities between habitats, with both unique and shared bacterial genera. These findings suggested the influence of habitat on microbial adaptations, influencing the Milkfish’s gut health and microbiota composition. They provide valuable insights into the effect of environmental factors on the gut microbiota of Milkfish and lay the groundwork for improved aquaculture management practices. Further studies involving functional analysis of the identified microbiota are recommended to enhance fish health and productivity.
Abstract Format
html
Abstract (Filipino)
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Abstract Format
html
Language
English
Format
Electronic
Keywords
Milkfish; Fresh water; Phylogeny; Bacteria
Recommended Citation
Chan, S. C., Dulay, E. Q., Luna, A. P., & Yao, M. D. (2025). Identification and characterization of culturable bacteria in the gut of milkfish, chanos chanos, forsskål (milkfish) from freshwater and marine environments. Retrieved from https://animorepository.dlsu.edu.ph/etdb_bio/211
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Embargo Period
8-7-2028
