RESUMO
The performance of a corn steam flaker was evaluated to improve steam-flaked corn (SFC) quality and investigate its feeding effects on nutritional value, productive performance, digestibility coefficients, and economic efficiency of growing rabbits. The flaker performance was studied as a function of change in steaming time, steam chest temperature and roll gap. Performance evaluation of the flaker was carried out in terms of flake thickness (FT), flake density (FD) and processing index (PI) as well as rabbit feeding trials. Experimental results clarified that values of FT, FD and PI are in the optimal limits under conditions of 118°C steam chest temperature, 40 min steaming time and 0.80 mm roll gap. Steam flaking is an acceptable process for rabbit feeds as SFC with optimal FD of between 0.36 and 0.39 kg/L corresponding to a PI of between 50.14% and 54.32% significantly improve the nutritional value of SFC compared with whole corn grain by 1.31%, 1.26% and 160.75% respectively. Also, SFC severely decreased the total count of harmful bacteria, fungi count and mortality rate compared to whole corn grain. Rabbits fed SFC processed to the density of 0.36 kg/L of the diet had better body weight gain, feed conversion ratio, organic matter digestibility, net revenue and economic efficiency of 9.29%, 8.89%, 4.65%, 15.62% and 15.43% compared with rabbit fed whole yellow corn grain respectively. In conclusion, it is convenient to entirely substitute whole corn grain with SFC to be utilised in rabbits' diets where achieved the best feeding effects results.