<p>This study evaluated the potential probiotic cocci of <i>Lactococcus lactis</i> MSH-08 and <i>Leuconostoc citreum</i> MSH-09, both individually and in combination, as alternatives to antibiotics for enhancing growth performance, immune response, blood lipid profiles, intestinal epithelial integrity, and gene expression in broiler chickens. <i>L. lactis</i> produced the highest concentration of lactic acid, while <i>L. citreum</i> had the highest production of acetic acid, butyric acid, and propionic acid. The strains were incorporated into feed at a level of 1.4 × 10⁹ CFU/mL (2.0 mL/kg of diet). A total of 320 Cobb-500 broiler chicks (7 days old) were randomly assigned to four dietary groups: a control group (basal diet), a group receiving <i>L. lactis</i> MSH-08, a group receiving <i>L. citreum</i> MSH-09, and a group receiving the combination of both probiotics. The results showed that <i>L. lactis</i> MSH-08 significantly improved body weight at 3 and 6 weeks and reduced feed conversion ratio during the first three weeks. The combination of both probiotics did not provide additional benefits. <i>L. lactis</i> MSH-09 also significantly lowered aspartate transaminase (AST) and creatinine levels, increased antioxidant capacity and immune response, and reduced uric acid levels compared to the control group. Furthermore, it improved intestinal morphology by increasing villus height and the villus height-to-crypt depth ratio in the duodenum at 6 weeks. Gene expression analysis revealed that the tumor necrosis factor alpha (<i>TNF</i>), Interleukin-8 (<i>IL-8</i>), Mucin 2 (<i>MUC2</i>), claudin-1 (<i>CLDN1</i>), and tight junction protein 1 (<i>TJP1</i>) were highly upregulated in the jejunum of <i>L. lactis</i> MSH-08 group. These findings suggest that <i>L. lactis</i> MSH-08 may be useful probiotic for improving growth performance and intestinal health of broilers without the use of antibiotics in poultry farming.</p>