Dose-response analysis for the effects of Coffea arabica L. on growth performance, health status, and economic efficiency of fattened rabbits raised under high ambient temperature

The dose-response analysis was used to investigate the effects of green coffee (GC) on growth performance, feed utilization, carcass traits, and health status of newly weaned rabbits. A total of 60 clinically healthy growing rabbits (5 weeks old) reared during summer season were divided randomly into three experimental groups, 20 rabbits each, and received 0, 2, and 4 g GC/kg diet, (GC0, GC2, and GC4), respectively. Growth performance (live body weight, LBW and average daily gain, ADG) and feed utilization (feed conversion ratio, FCR) as well as the dressing percentage and the relative weight of liver were improved significantly in the GC-treated groups compared to the control group. The dose-response regression analysis showed that the optimal doses were 2.75 and 3 g GC/kg diet for ADG and FCR, respectively. Moreover, GC treatments significantly decreased both rectum temperature and respiration rate compared to GC0, with an optimal dose being at 2.5 g GC/kg diet. Erythrocytes and leukocyte counts improved significantly in the GC-treated groups compared to the GC0 group. Blood protein and its fractions, liver and kidney functions, and lipid profile were quadratically improved by GC supplementation. The optimal dose was 3 g GC/kg diet for total protein and its fractions, ALT, and TG, while it was 2.5 and 2.75 g GC/kg diets for creatinine and TC, respectively. Total antioxidant capacity, superoxide dismutase, and glutathione activities were significantly higher, while the levels of malondialdehyde were significantly lower in the GC-treated groups than the GC0 group. A level of 2.5 g GC/kg diet was the optimal dose required for improving immunoglobulin A and G, which improved in blood serum of GC treated groups compared to the control. Economically, dietary addition of GC enhanced the economic efficiency of the supplemented diets, thereby improving the profitability of the fattening process. In conclusion, dietary supplementation of GC at level of 2.5–3 g/kg diet could be effectively used to enhance the growth indices, redox status, immune function, and economic efficiency of rabbits fattened during the summer season.