Isolation and identification of autochthonous potential probiotic candidates from the gastrointestinal tract of Caspian striped mullet (Mugil cephalus)

Authors

1 Department of Food Hygiene, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran

2 Department of Pathobiology, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran

3 Department of Clinical Sciences, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran

10.22092/ijfs.2026.135972

Abstract

This study aimed to screen and identify potential probiotic strains from the gastrointestinal tract of Caspian striped mullet (Mugil cephalus). Eight out of forty isolates showed antibacterial activities against fish-associated pathogens: Yersinia ruckeri, Salmonella enterica, Escherichia coli O157:H7, and Staphylococcus aureus. Biochemical tests showed that 50% of the isolates were capable of glucose fermentation, 75% fermented arabinose, 37.5% and 62.5% were able to metabolize raffinose and mannitol, respectively. None of the eight isolates demonstrated the ability to ferment all tested sugars. The isolates demonstrated tolerance to a high bile concentration (4000 mg/L) as well as to mildly acidic and alkaline pH conditions. Three isolates exhibited100% sequence identity with Carnobacterium maltaromaticum. One of the isolates exhibited 99% sequence identity with Carnobacterium divergens. Two isolates exhibited 71% sequence identity with Weissella koreensis and other Weissella species. Sequencing analysis revealed that the fish gut isolates are closely related to lactic acid bacteria, particularly C. maltaromaticum and C. divergens. The results indicate that the isolates have potential as probiotics in aquaculture due to ability to enhance gut health and suppress pathogenic bacteria.

Keywords

Iranian Journal of Fisheries Sciences
Volume 25, Issue 4
July 2026
Pages 771-786

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