Effect of phloretin on antioxidant status, inflammatory cytokines, blood and biochemical indices, cecal microbial load, and growth performance in broiler chickens subjected to pulmonary arterial hypertension

This experiment was conducted to investigate the effects of dietary phloretin on broiler chickens under pulmonary arterial hypertension (PAH) conditions. A total of 500 one-day-old male broiler chickens were randomly allocated into five treatments with five replicate pens containing 20 birds per pen. The negative control group was reared at normal temperature and fed with basal diet while the PAH-treatments (positive control, F-200, F-400, and F-600) were exposed to low temperatures and received drinking water supplemented with excess salt to induce PAH and fed with basal diet containing 0, 200, 400, and 600 mg of phloretin per kilogram, respectively. Blood samples were collected from broilers at 42 days of age. Results showed that PAH decreased body weight gain (BWG), antioxidant capacity, immunoglobulin G (IgG), hematological indices, and cecal lactic acid bacteria population (CLBP), but increased feed intake (FI), PAH-related mortality, feed conversion ratio (FCR), PAH index, and pro-inflammatory cytokines, alanine transaminase (ALT), aspartate transaminase (AST), triglyceride (TG), and total cholesterol (TC) contents in serum (P<0.001). Among the PAH treatments, supplementary phloretin improved growth performance indices and reduced PAH index, and PAH-related mortality (P < 0.01). The activities of superoxide dismutase, catalase, and glutathione peroxidase, and IgG, and IgM in serum were increased, and malondialdehyde was reduced by phloretin supplementation (P <0.01). The PAH-induced effect on contents of pro-inflammatory cytokines were reduced by dietary phloretin supplementation (P <0.01). Moreover, supplementation of diets with phloretin alleviated the adverse effect of PAH as reflected by a reduction in ALT, AST, TG, and TC (P <0.01). The red blood cell count, hemoglobin, hematocrit, and heterophil levels reduced by phloretin supplementation. Phloretin increased the population of CLBP. In conclusion, phloretin supplementation during PAH may mitigate PAH-associated physiological and biochemical alterations in broiler chickens.