Abstract

Objectives: This study evaluated the effects of a novel Symbiotic Microbial Complex (SMC) as a non-nutritive additive on the productive performance, hematological parameters, and serum biochemistry of broiler chickens reared under environmental stress.
Materials and Methods: A total of 264 one-day-old Ross broiler chickens were assigned to two treatments: A Control and an SMC treatment (10% dietary inclusion), with three replicates of 44 birds each, for 42 days. Diets were isoproteic and isoenergetic for the Pre-starter (1–10 days), Starter (11–22 days), and Finisher (23–42 days) phases. Environmental parameters (averaging 29.6°C) and water quality (Nitrates) were monitored. Weekly evaluations of production variables, hematology, and serum biochemistry were performed. Data were analyzed using one-way ANOVA and Chi-square tests.
Results: Inclusion of SMC significantly reduced cumulative mortality in the Pre-starter (20.45% Control vs. 3.03% SMC) and Starter phases (6.06% Control vs. 0.00% SMC) (p < 0.05). While no significant differences were observed in body weight or feed conversion ratio, the SMC treatment exhibited greater physiological stability. Liver enzyme activity (ALT/AST) was lower in SMC birds during metabolic peaks, and lipid profiles remained within normal physiological ranges despite environmental challenges.
Conclusions: The SMC acted as a potent bioprotector, significantly enhancing early viability and maintaining systemic homeostasis. Its protective effect buffered the physiological toll of environmental heat and suboptimal water quality. However, its growth-promoting potential may be optimized under controlled environmental settings where metabolic energy is not prioritized for survival and homeostatic maintenance.

Key words: Animal performance; Bacillus; homeostasis; non-nutritive additive; metabolic resilience; serum biochemistry