Dietary effects of multi-strain probiotics as an alternative to antibiotics on growth performance, carcass characteristics, blood profiling and meat quality of broilers

Abstract

The growing issue of antibiotic resistance, particularly driven by the overuse of antibiotics in poultry farming in developing countries, presents serious public health threats. This situation highlights the urgent need for alternatives that benefit both poultry and human health. Probiotics, as live microorganisms administered in proper amounts, are a promising substitute, enhancing host health without harmful residues. This study evaluated the effects of lyophilized probiotic-based starter feed versus antibiotics on the growth performance, carcass traits, serum metabolites, and meat quality of broiler chicks. As experimental feed additives, ciprofloxacin, often used in the poultry industry of developing nations, and lyophilized multi-strain probiotics (2.8×109 CFU/g) isolated from chicken intestines, included Bacillus tropicus strain MCCC 1A01406, Bacillus tequilensis strain 10b, Staphylococcus gallinarum strain VIII, Lactobacillus salivarius strain HO 66, and Staphylococcus hominis strain DM 122 were utilized. A total of 300 Cobb-500 broiler chicks were divided into four groups, each with three replicates of 25 chicks, in a completely randomized design: (1) control (basal diet), (2) basal diet + 500 mg ciprofloxacin/kg feed (T1), (3) basal diet + 250 mg probiotics/kg feed (T2), and (4) basal diet + 500 mg probiotics/kg feed (T3). Growth performance was measured manually, serum biochemicals via avian diagnostic kits, and meat composition through Kjeldahl (protein) and Soxhlet (lipid) methods. After three weeks, probiotic-fed chicks showed significant increases (P<0.05) in body weight, feed intake, and feed conversion ratio compared to control and antibiotic groups. Serum analysis revealed increased (P<0.05) protein, calcium, and RBC levels and reduced cholesterol and uric acid. Meat from probiotic-fed groups had better (P<0.05) antioxidant properties, higher protein, and fiber, and lower fat, ash, and nitrogen-free extract levels, suggesting probiotics as a sustainable antibiotic alternative for poultry farming and public health improvement.