Lactic Acid Bacteria Isolated from Poultry: Phenotypic Characterization Based on Total Plate Count, Gram Staining Test and Hemolytic Activity

Faculty of Animal Science, Universitas Brawijaya, Malang, East Java Province, Indonesia, 65145

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Abstract

This study aims to characterize lactic acid bacteria (LAB) isolated from the ileum of broiler chickens and native chickens based on total colony count, Gram reaction, and hemolytic activity. Samples were isolated from the small intestine contents of five broiler chickens and five native chickens aged 35 days using selective de Man Rogosa and Sharpe Agar (MRSA) media. The research methodology included Total Plate Count (TPC) counting, Gram staining for cell morphology identification, and hemolysis testing on blood agar media for preliminary safety assessment. The TPC test results showed that the microbial population in broiler chickens (range 2,0×10⁷ to 2,7×10⁷ CFU/ml) was significantly higher than in native chickens (range 3,1×10⁶ to 5,8×10⁶ CFU/ml) based on an independent t-test (p < 0,05). Isolates selected from the group with the highest TPC were identified as Gram-positive rod-shaped (bacilli) bacteria. In the hemolytic activity test, the isolates showed γ-hemolysis (non-hemolytic) characteristics, which were marked by the absence of clear zones around the colonies on blood agar media. The LAB isolates obtained met the initial safety criteria as probiotic candidates due to their non-pathogenic nature, which does not lyse red blood cells. These isolates have the potential to be further developed as poultry feed additives.