The present disclosure relates to an immune-enhancing composition comprising Lactobacillus rhamnosus LM1019 and starter strains. An immune-enhancing composition comprising Lactobacillus rhamnosus LM1019 and starter strains according to the present disclosure has an excellent immune-enhancing effect by increasing the amount of nitric oxide (NO) produced and improving the TNF- secretion ability. Also, since the immune-enhancing composition contains the starter strain, it can be used to produce fermented milk. Under the provisions of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure, the Lactobacillus rhamnosus LM1019 strain was deposited with the international depositary authority: the Korean Culture Center of Microorganisms (KCCM) on Aug. 11, 2017, under the Accession Number: KCCM12308P.

The present invention relates to efficient delivery of anti-infective activity, immunomodulatory factors, or growth-promoting biomolecules directly to the digestive tract of an animal via a live delivery platform. The live delivery platform can be a genetically modified microorganism. Delivery can be accomplished with a Lactobacillus sp which colonizes the gastrointestinal tract. The anti-infective activity can be a bacteriocidal or bacteriostatic peptide, an antibody or fragment thereof which specifically recognizes a pathogen, or a phage, or a lytic peptide from a phage which specifically targets a certain pathogen.