Efficacy of indigenous Lacticaseibacillus paracasei from dadih on growth performance, hepatoprotection, and economic efficiency in broilers challenged with avian pathogenic Escherichia coli

Abstract

Background and Aim: Avian pathogenic Escherichia coli (APEC) is a major cause of colibacillosis in broiler chickens, leading to impaired growth, liver dysfunction, and substantial economic losses. Increasing restrictions on antibiotic growth promoters (AGPs) due to antimicrobial resistance have intensified the search for sustainable alternatives. Indigenous probiotics isolated from traditional fermented foods may provide effective region-specific solutions. This study evaluated the efficacy of indigenous Lacticaseibacillus paracasei isolated from dadih on growth performance, carcass traits, hepatoprotection, and economic efficiency in broilers challenged with APEC and compared its effectiveness with that of a conventional AGP. Materials and Methods: Eighty one-day-old male broiler chickens were randomly assigned to four treatment groups with five replicates of four birds each: uninfected control (T0), APEC-infected control (T1), AGP-treated (zinc bacitracin; T2), and probiotic-treated (L. paracasei 153 Vi; T3). Birds were orally challenged with APEC (1.5 × 10⁸ colony-forming units [CFU]/mL) at 21 days of age. The probiotic was administered through drinking water (5 mL/L; 1.2 × 10⁹ CFU/mL), whereas zinc bacitracin was incorporated into feed (1 g/kg). Feed and nutrient intake, final body weight, carcass characteristics, serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), and Income Over Feed Cost (IOFC) were evaluated. Data were analyzed using one-way analysis of variance followed by Duncan’s Multiple Range Test at p < 0.05. Results: The AGP group exhibited the highest feed and nutrient intake. However, the probiotic group achieved the greatest final body weight (1993.0 g), carcass weight (1337.8 g), and carcass percentage (68.75%) (p < 0.05). L. paracasei supplementation markedly reduced SGPT (105.07 U/L) and SGOT (59.05 U/L) compared with the infected control, demonstrating superior hepatoprotective activity. Economic analysis showed that the probiotic treatment generated the highest IOFC at both experimental and farm scales, substantially exceeding the AGP-treated and infected control groups. Conclusion: Indigenous L. paracasei isolated from dadih effectively improved growth performance, carcass yield, liver function, and economic returns in APEC-challenged broilers, outperforming the conventional AGP under the conditions of this study. These findings support its potential as a safe, sustainable, and economically viable alternative to AGPs for improving poultry productivity while contributing to strategies aimed at reducing antimicrobial use in commercial broiler production. Keywords: antibiotic growth promoter alternative, avian pathogenic Escherichia coli, dadih, economic efficiency, hepatoprotection, Lacticaseibacillus paracasei, probiotics, zero hunger.