The beneficial impacts of dietary phycocyanin supplementation on growing rabbits under high ambient temperature

A total of 120 growing rabbits (7-weeks old) reared under high ambient temperature were divided into four equal groups, 30 rabbits each. The first group was received a basal diet without Phycocyanin (PC) (0 g/kg diet) and served as a control (PC0). The other three groups were received diets containing PC (50 (PC50), 100 (PC100), 150 (PC150) mg/kg diet, respectively). Live body weight (LBW) and feed conversion ratio (FCR) were enhanced significantly by 11.83% (p = .028) and 18.23% (p = .002) in PC50 group, and; respectively, compared with the PC0 group. Red blood cells, platelet, and haemoglobin values were significantly increased, while white blood cells were reduced (p = .033) in rabbits received diets containing PC (50, 100 and 150 mg/kg) compared to the PC0 group. Plasma urea, total bilirubin, and the gamma gamma-glutamyl transferase in the group PC100 were significantly higher than those in the PC group. Compared with the PC150 and control groups, treatment with 50 or 100 mg/kg decreased plasma interleukin-4 (p < .0001) and interferon gamma (p < .0001) levels, but increased the levels of nitric oxide (p < .0001). Activities of antioxidants indices were improved (p < .0001) in the group treated with PC (50 and 100 mg/kg). However, lipid peroxidation (malondialdehyde) was decreased (p = .001) in PC50 compared with the other groups. The caecal bacterial populations were lowered in the groups treated with (50, 100 and 150 mg/kg) compared with those in the PC0 group. Conclusively, dietary inclusion of PC (100 mg/kg) could be effectively used to enhance the performance, antioxidants indices, decrease inflammatory responses and intestinal pathogens and hence enhance the health status of growing rabbits during the summer season.