According to the present invention there are provided methods of regulating the immune system of a companion animal and methods of improving the digestion of a companion animal, wherein each of said methods comprises administering to a companion animal a probiotic bacteria strain of the genus Bifidobacteria.

The invention provides a probiotic formulation that includes an LDH-deficient mutans streptococcus strain and an attenuated S. oralis strain. S. uberis strains can be included in the probiotic formulation. Such a probiotic formulation is suitable for persistently or permanently colonizing the oral cavity with beneficial bacteria,

The invention provides a probiotic formulation that includes an LDH-deficient mutans streptococcus strain and an attenuated S. oralis strain. S. uberis strains can be included in the probiotic formulation. Such a probiotic formulation is suitable for transiently colonizing the oral cavity with beneficial bacteria.

Growth medium are disclosed for use in fermenting a marine microorganism. The medium comprise Potassium, Calcium, Strontium, Borate and Fluoride at specific concentrations. Alternatively, the growth medium comprises cobalt at specified concentrations or comprises vitamin B.sub.12 at specified concentrations. Methods of producing certain desired compound by fermentation of a marine microorganism are also disclosed.

The invention provides a probiotic formulation that includes an LDH-deficient nutans streptococcus strain and an attenuated S. oralis strain. S. uberis strains can be included in the probiotic formulation. Such a probiotic formulation is suitable for transiently colonizing the oral cavity with beneficial bacteria,

Growth medium are disclosed for use in fermenting a marine microorganism. The medium comprise Potassium, Calcium, Strontium, Borate and Fluoride at specific concentrations. Alternatively, the growth medium comprises cobalt at specified concentrations or comprises vitamin B.sub.12 at specified concentrations. Methods of producing certain desired compound by fermentation of a marine microorganism are also disclosed.

The invention provides compositions comprising one or more isolated LDH-deficient mutans streptococcus strains and one or more isolated S. oralis strains and/or one or more isolated S. uberis strains. Compositions of the invention are useful to maintain oral health, by for example treating and/or preventing one or more symptoms of dental caries, periodontitis and/or other oral cavity diseases or wounds.

The invention provides compositions comprising one or more isolated LDH-deficient mutans streptococcus strains and one or more isolated S. oralis strains and/or one or more isolated S. uberis strains. Compositions of the invention are useful to maintain oral health, by for example treating and/or preventing one or more symptoms of dental caries, periodontitis and/or other oral cavity diseases or wounds.

Growth medium are disclosed for use in fermenting a marine microorganism. The medium comprise Potassium, Calcium, Strontium, Borate and Fluoride at specific concentrations. Alternatively, the growth medium comprises cobalt at specified concentrations or comprises vitamin B.sub.12 at specified concentrations. Methods of producing certain desired compound by fermentation of a marine microorganism are also disclosed.

Growth medium are disclosed for use in fermenting a marine microorganism. The medium comprise Potassium, Calcium, Strontium, Borate and Fluoride at specific concentrations. Alternatively, the growth medium comprises cobalt at specified concentrations or comprises vitamin B.sub.12 at specified concentrations. Methods of producing certain desired compound by fermentation of a marine microorganism are also disclosed.