Dietary effects of citric acid monohydrate on the growth performance, carcass characteristics, haemato-biochemical markers, antioxidant enzyme activities, intestinal histomorphology, and caecal microbial count in broiler chickens

This study investigated the dietary impact of citric acid monohydrate (CAM) on the growth performance, carcass characteristics, blood parameters, intestinal histomorphology, and caecal microbial count in broiler chickens. 300 day-old male Arbor Acres chicks were randomly allocated to 5 dietary treatments with 5 replicates of 12 birds each in a completely randomised design for a 49-day study. The treatment groups were fed a basal diet supplemented with 0%, 0.5%, 1.0%, 1.5%, and 2.0% CAM, respectively. During the starter phase, CAM supplementation linearly improved final body weight (BW; p = 0.007), average daily gain (ADG; p = 0.004), and feed conversion ratio (FCR; p = 0.010), without significantly affecting average daily feed intake (ADFI). Similarly, during the finisher phase and the overall phase, CAM enhanced final BW, ADG, and FCR. ADFI decreased in birds fed CAM during the finisher phase (p < 0.05); however, no significant effect was observed on overall ADFI (p > 0.05). Although carcass traits were unaffected (p > 0.05), CAM improved small intestine length and weight (p < 0.001). Haematological parameters were unaffected except for neutrophils. Serum proteins were significantly (p < 0.05) higher in broilers that received CAM, with broiler birds fed 2.0% CAM having the highest values compared to other treatment groups. Serum enzymes decreased in broilers fed CAM. Compared with the control group, the treatment groups presented lower total cholesterol and urea levels. Except for calcium and phosphorus, the serum electrolytes did not differ (p > 0.05). Broilers fed CAM improved total antioxidant capacity, glutathione peroxidase, catalase, and superoxide dismutase, with decreased malondialdehyde. CAM improved small intestine histomorphological traits (villi height, crypt depth, villi width, epithelial thickness, and muscularis thickness) across the treatment groups. A significant (p < 0.05) increase in Lactobacillus counts, alongside reduced total viable counts, Salmonella, and Escherichia coli, was observed in the caecum of broilers fed CAM. Conclusively, dietary supplementation with CAM at 2.0% enhanced growth performance, gut health, and positively influenced health status in broiler chickens. Citric acid monohydrate improved growth performance and feed conversion ratio in broiler chickens. Citric acid monohydrate improved gut health by improving intestinal histomorphological traits and reducing pathogenic microbial load in the caecum. Blood parameters were not adversely affected, and antioxidant enzyme activities were significantly enhanced.