Combined Effects of Superdose Phytase and Organic Acid Supplementation on Growth Performance, Blood Biochemical Parameters, and Litter Characteristics in Broiler Chickens Fed Phosphorus-Deficient Diets

<title>Abstract</title> <p>Background Optimizing the health and performance of broiler chickens through nutritional strategies is a key objective in poultry science, particularly for sustainable production and reduced nutrient excretion. Feed enzymes and organic acids have emerged as viable nutritional interventions to enhance growth and nutrient utilization in broilers Objectives This study aimed to evaluate the combined effects of superdose phytase and an organic acidifier on growth performance, blood biochemical parameters, and litter nitrogen content in broiler chickens fed either phosphorus-adequate or reduced-phosphorus diets. Methods A total of 400 one-day-old Ross 308 broiler chickens were used in a completely randomized design with five dietary treatments, four replicates per treatment, and 20 birds per replicate. The treatments were as follows: (1) Control (basal diet); (2) Control + Phytase (2000 FTU/kg); (3) Control + Acidifier (3 g/kg); (4) Control + Phytase + Acidifier; and (5) Low-phosphorus diet + Phytase + Acidifier. Performance metrics, blood biochemistry, and nitrogen utilization were evaluated over a 42-day period. Results Over the overall period (d 1–42), daily weight gain was significantly higher in birds fed the LPHAC diet compared to those receiving the ACI diet (P &lt; 0.05), while feed conversion ratio showed a improving numerical tendency (P = 0.086). Furthermore, serum alkaline phosphatase (ALP) activity was significantly elevated in the ACI group compared to the control group (P &lt; 0.05). Notably, litter nitrogen excretion was significantly reduced in birds fed the LPHAC diet compared to the control group (P &lt; 0.05), without adversely affecting systemic blood biochemical parameters. Conclusions The combined supplementation of superdose phytase and an organic acidifier, particularly under reduced dietary phosphorus conditions, effectively maintains growth performance, improves weight gain, and reduces litter nitrogen excretion in broilers. This combination represents an efficient and environmentally friendly nutritional strategy for sustainable poultry production.</p>