With an attempt to screen bacteria with potential probiotic effects on Manila clam(Ruditapes philippina-rum),culturable bacteria were first isolated from the intestinal tract of the healthy clam and then subject to enzyme-producing ability examination by in vitro plate experiment.Those enzyme-producing strains were,morphologically observed and molecularly identified by plate counting method and the standard curve between the absorbance value and the bacterial cell number.The bacterium was examined for acid and bile salt tolerance,and the safety of the enzyme-producing bacterium on R.philippinarum larvae by challenging test.The Manila clam juveniles were reared to examine growth promoting effects.The results showed that a bacterial strain isolated from the intestinal tract of healthy clams designated as C26 produced amylase,protease and lipase was gram-negative and belonged to the ge-nus of Pseudoalteromonas,with tolerabce to pH value of higher than 4.5 and a bile salts concentration ranging from 0 g/100 mL to 0.1 g/100 mL.In addition,Strain C26 had no pathogenicity to R.philippinarum and significantly im-proved the weight gain rate of the juveniles(P<0.05).To sum up,a safe Pseudoalteromonas strain C26 was screened and had probiotic effects on Manila clam larvae,which provides foundation for enrichment of the Manila clam probiotic strain resources.
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