Lactococcus garvieae is known as main agent of the bacterial diseases, Lactococcosis in trout farms.
The present study was aimed to study the metabolic bases of the temperature-dependent
pathogenicity of the L. garvieae using 1H NMR spectroscopy. The bacteria were grown at different
temperatures, including 10, 14, 18 and 22˚C and then the metabolites extracted, identified and
quantified. The results of PLS-DA analysis clearly separated the experimental treatments. The main
metabolites responsible for this separation were acetate, acetoacetate, creatine phosphate,
succinylacetone and trehalose. Furthermore, the result of the analysis of variance indicated also
significant differences in metabolome content between temperature treatments. The bacteria exposed
to higher temperatures showed more concentration of acetate and acetoacetate compared to those
grown at 10°C. The concentrations of trehalose were higher in the bacteria grown at 14 and 18°C
compared to other temperature treatments. The higher levels of succinylacetone were found in the
bacteria exposed to the temperature less than 14°C compared to those grown at 18 and 22°C. The
creatine phosphate concentrations increased with temperature, however, a significant decline
occurred at 22°C. The levels of isoeugenol, methionine and betaine significantly declined with
increase of temperature from 10 to 22°C. Also, the concentration of N-Acetylglutamine significantly
raised as the temperature increased from 10 to 22°C. In conclusion, the temperature altered the
metabolome of L. garvie, which this may be linked to the pathogenicity. The temperature probably
affects fermentation, homeostasis, energetic condition and metabolism of amino acids in L. garvieae.