Nutraceuticals vs. antibiotic growth promoters: differential impacts on performance, meat quality, blood lipids, cecal microbiota, and organ histomorphology of broiler chicken.

The main goal of this study was to evaluate the effect of nutraceuticals vs. in-feed antibiotics on performance, blood lipids, antioxidant capacity, cecal microbiota, and organ histomorphology of broiler chickens. A total of 320 one-day-old male broiler chickens were distributed into 5 treatment groups with 8 replicates each. The control group was fed on a basal diet without any additives (NC); the antibiotic group was fed on a basal diet supplemented with 100 mg kg-1 avilamycin (PC); the algal group was fed on a basal diet supplemented with a mixture of Spirulina platensis and Chlorella vulgaris (1.5 g + 1.5 g/kg feed) (SP+CV); the essential oil group was fed with a basal diet containing 300 mg/kg feed rosemary oil (REO); and the probiotics group (a mixture of 1 × 10 11 CFU/g Bacillus licheniformis, 1 × 10 11 CFU/g Enterococcus facieum, 1 × 10 10 CFU/g Lactobacillus acidophilus, and 2 × 10 8 CFU /g Saccharomyces cerevisiae) was fed with a basal diet supplemented with 0.05% probiotics (PRO). The experiment lasted for 35 d. A beneficial effect of SP+CV and PRO (P < 0.01) was noticed on final body weight, body weight gain, feed conversion ratio, and breast yield. The dietary supplementation with SP+CV, REO, and PRO increased (P < 0.001) broilers' cecal lactic acid bacteria count compared to the control. Lower cecal Clostridium perfringens and Coliform counts (P < 0.001) were noticed in chickens fed the PC and supplemental diets. Malondialdehyde (MDA) concentration was decreased, while glutathione peroxidase (GPx), superoxide dismutase, and catalase enzymes were increased in the breast and thigh meat (P < 0.001) of broiler chickens fed SP+CV, REO, and PRO diets. Dietary SP+CV, REO, and PRO supplementation decreased (P < 0.001) serum total lipids, cholesterol, triglycerides, low-density lipoprotein, and MDA, but increased serum high-density lipoprotein and GPx compared to PC and NC. No pathological lesions were noticed in the liver, kidney, or breast muscle among broilers. The SP+CV, REO, and PRO groups had greater (P < 0.001) intestinal villi height and crypt depth while lower goblet cell densities (P < 0.01) than the control. The present findings suggest that PRO and SP+CV, followed by REO could be suitable alternatives to in-feed antibiotics for enhancing the performance, health, and meat quality of broiler chickens.