Screening and identification of a eurythermal probiotic bacterium in the intestine of cultured Scophthalmus maximus

Abstract:

One potential probiotic bacterium TYTG1 screened from the intestine of cultured Scophthalmus maximus was obtained. The antagonism of bacterium TYTG1 to turbot pathogens Vibrio archariae and V. scophthalmi was evaluated. Based on the morphological observations, physiological and biochemical characteristics and 16S rDNA sequence analysis, the bacterium was identified as Bacillus subtilis. This is the first report on B. subtilis being found in the intestine of cultured S. maximus in China. The TYTG1 is a eurythermal bacterium that can grow at 4~42 ℃. S. maximus could grow without any abnormal phenomenon as they were fed with the TYTG1 bacterial cells at densities of 107 or 109 CFU/g for 4 weeks. The bacterium exhibited an excellent antagonism to the pathogens V. archariae and V. scophthalmi which could cause ascetic and enteric diseases in turbots. Therefore this probiotic bacterium is a potential candidate to be applied in turbot culture.