This study was conducted to evaluate the feasibility of using L. reuteri Pg4, a strain isolated from the gastrointestinal (GI) tract of healthy broilers, as a probiotic. In preliminary in vitro studies the Pg4 strain was proven capable of tolerating acid and bile salts, inhibiting pathogenic bacteria and can adhere to intestinal epithelial cells. The probiotic properties were then evaluated on the basis of the broiler's growth performance, intestinal microbial population and cecal volatile fatty acid and lactic acid concentrations under conventional feeding. Dietary supplementation of dried L. reuteri Pg4 decreased significantly feed intake in grower chickens and improved significantly the feed conversion by 5% in a 0-6 weeks feeding period compared with the control group. The Lactobacillus counts in the crop, ileum, and cecum of the probiotic group were higher than in the control group. The L. reuteri Pg4 strain was traceable in the GI tract of probiotic supplemented chicks and showed capability of survival in the intestine for a protracted period. The probiotic group had a higher lactic acid concentration and lower pH value in the cecum than the control chicks. Probiotic supplement also affected the histology of the intestinal mucosa of chicks. The present findings demonstrated that L. reuteri Pg4 possesses probiotic characteristics and it is suggested, therefore, that the organism could be a candidate for a new probiotic strain.
Two novel hydrogenotrophic methanogens, designated strains P2F9704aT and P2F9705, were isolated from an estuary in Eriln Shi, Taiwan. The cells of strain P2F9704aT were non-motile, irregular cocci 0.9-1.4 microm in diameter. They stained gram-negative. The cells catabolized formate and H2+CO2 to produce methane, but did not utilize acetate, methanol, trimethylamine, ethanol or secondary alcohols as methanogenic substrates. The optimal growth parameters for strain P2F9704aT were pH 6.7, 37 degrees C and 0.5% NaCl. Acetate was required for cell growth even though it was not a substrate for methanogenesis. The trace element tungsten was not required but slightly stimulated the growth of strain P2F9704aT. However, tungsten extended the growth ranges relating to temperature, pH and salt. The sequences of the 16S rRNA genes of strains P2F9704aT and P2F9705 were nearly identical and possessed 99.1 and 98.5% similarity to the genes of Methanocalculus pumilus and Methanocalculus halotolerans, respectively. In addition, strain P2F9704aT possessed 14 and 12% DNA relatedness with respect to Methanocalculus pumilus and Methanocalculus halotolerans, respectively. In addition, the optimal salt concentrations, the cellular protein profiles and the molecular masses of surface-layer protein subunits of strain P2F9704aT were different from those of the other two known Methanocalculus species. On the basis of these observations, it is proposed that these two organisms should be placed in a new species, namely Methanocalculus taiwanensis. The type strain is P2F9704aT (= OCM 671T = CCRC 16182T = DSM 14663T).
A new methanogenic isolate, designated as strain O1M9704 (=OCM 667), was isolated from the sediment of the estuarine environment in Eriln Shi, Taiwan. This strain grew on trimethylamine and methanol, but it did not catabolize H2-CO2, acetate, or formate. Cells grew optimally at 37 degrees C with 0.5% NaCl in neutral pH. The cells were stained Gram-negative, nonmotile, irregular coccus 0.3-0.6 microm in diameter. A comparison of 16S rDNA sequences phylogenetically related strain O1M9704 to Methanosarcina mazei. Gas vacuoles were observed both under phase contrast microscope and in thin sections in the electron microscope. Negative stain of electron micrographs showed a novel character of strain O1M9704. with tubule structure extended out of the cells. The tubule structure and gas vacuoles may benefit the adaptation of methanoarchaea in estuarine environment.
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