1. Various dosages of metabolite combinations of the Lactobacillus plantarum RI11, RG14 and RG11 strains (COM456) were used to study the egg production, faecal microflora population, faecal pH, small intestine morphology, and plasma and egg yolk cholesterol in laying hens. 2. A total of 500 Lohmann Brown hens were raised from 19 weeks to 31 weeks of age. The birds were randomly divided into 5 groups and fed on various treatment diets: (i) basal diet without supplementation of metabolites (control); (ii) basal diet supplemented with 0·3% COM456 metabolites; (iii) basal diet supplemented with 0·6% COM456 metabolites; (iv) basal diet supplemented with 0·9% COM456 metabolites; and (v) basal diet supplemented with 1·2% COM456 metabolites. 3. The inclusion of 0·6% liquid metabolite combinations, produced from three L. plantarum strains, demonstrated the best effect in improving the hens' egg production, faecal lactic acid bacteria population, and small intestine villus height, and reducing faecal pH and Enterobacteriaceae population, and plasma and yolk cholesterol concentrations. 4. The metabolites from locally isolated L. plantarum are a possible alternative feed additive in poultry production.