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Large-bodied animals, such as the Mekong giant catfish (Pangasianodon gigas), may modify prey communities and affect their potential competitors for food resources by consuming large quantities of prey. The Mekong giant catfish is a key representative of freshwater megafauna and is stocked in reservoirs in Thailand for species conservation and fishery stock enhancement. However, their biological interactions with other sympatric animals remain unclear. Here, we aimed to investigate the trophic niche of the Mekong giant catfish in a Thai reservoir by comparing stable carbon and nitrogen isotope ratios (δ13C and δ15N, respectively) and fatty acid (FA) composition with those of five other sympatric fish species. The δ13C value of the Mekong giant catfish was –24.4 ± 1.0‰ (mean ± SD), the second highest among the sympatric fish species, suggesting relatively weak reliance on phytoplankton-based food chains. The δ15N value of the Mekong giant catfish was 10.7 ± 0.4‰, intermediate between those of herbivorous and carnivorous fishes, indicating that it is not a primary consumer. The FA composition of the Mekong giant catfish significantly differed from those of the other fish species and was characterized by a large proportion of long-chain FA, including 22:6n-3, 20:5n-3, and 20:1n-9. The δ13C, δ15N, and FA signatures suggest that the Mekong giant catfish occupy distinct trophic niches in food webs. Our results highlight that it is necessary to monitor the ecological impacts of released Mekong giant catfish on lower-level consumers through their foraging in receiving reservoirs. [ABSTRACT FROM AUTHOR]

Fermented foods are produced as a result of a preservation process that adds value to the final food product. This study aimed to evaluate the chemical components and radical scavenging activity of 11 fermented fish products from Thailand. Lipids extracts were used for the analysis of fatty acids, tocopherol, and radical scavenging activity, and water-soluble extracts were used for the analysis of free amino acids, inosine 5′-monophosphate (IMP), organic acids, and radical scavenging activity. The results showed that nam pla contained high levels of free amino acids and IMP; tai pla contained high levels of free amino acids and IMP; and kapi contained high levels of n – 3 fatty acids, α-tocopherol, free amino acids, and IMP. These three fermented foods also had higher radical scavenging activities than the other tested fermented foods. Furthermore, a strong correlation between chemical component and radical scavenging activity also occurs by principal component analysis. [ABSTRACT FROM AUTHOR]

Two bacterial strains, designated as 1-4-3 T and 1-4-4, were isolated from a mangrove sediment cultured with coastal seawater. The cells were Gram-stain-negative, motile, short, rod-shaped bacteria with flagella. Growth occurred at 4-37 °C, pH 7.0-9.0, and 0-7% NaCl. The predominant fatty acids of the novel strains were C 18 : 1  ω7 c, C 19 : 0 cyclo ω 8c, C 18 : 0 , and C 16 : 0 . A phylogenetic analysis based on 16S rRNA gene sequences and whole genome phylogeny analysis based on distance matrix revealed an affiliation between the two strains and the genus Aureimonas , with closest sequence similarity to A. populi 4M3-2 T (96.41 and 96.64% similarity, respectively) and A. glaciistagni (96.01 and 96.23% similarity, respectively). The DNA G+C content of strain 1-4-3 T was 66.80 mol%. Strain 1-4-3 T displayed low DNA-DNA relatedness to A. populi 4M3-2 T , with an average nucleotide identity value of 77.47 % and digital DNA-DNA hybridization value of 22.83 %. Genotypic, chemotaxonomic, and phenotypic data indicate that strains 1-4-3 T and 1-4-4 represent a novel species of the genus Aureimonas , for which we propose the name Aureimonas mangrovi sp. nov. The type strain is 1-4-3 T (=LMG 31693 T =CGMCC 1.18507 T ).