The nutrition of meat-type ducks. 1. The effects of dietary protein in isoenergetic diets on biological performance

An experiment was conducted with 1-day-old male and female White Pekin ducklings and four dietary protein levels (18, 20, 22 and 24%) from 0 to 2 weeks and eight dietary protein (%) combinations (18/18, 20/20, 24/24, 18/16, 20/16, 22/16, 24/16) from 3 to 8 weeks in isoenergetic (12.7 MJ metabolizable energy (ME)/kg) diets to determine the optimum protein level needed for maximum biological performance of meat-type ducks. At 8 weeks of age male ducks were heavier, had better feed conversion ratios and less carcass fat than females. For both sexes carcass fat increased substantially between 6 and 8 weeks. Younger ducklings had better efficiency of energy utilization than older ducks. Dietary protein levels did not affect the energetic efficiency of gain, efficiency of energy utilization and carcass composition at 8 weeks. The significant effect of dietary protein on the fat content of the wet carcasses was observed in ducklings at 2 and 4 weeks, and a similar trend was seen at 6 weeks. It is suggested that for growth rate and feed conversion efficiency, 19 and 16 % levels of protein in diets containing 12.7 MJ ME/kg are adequate to meet the protein needs of Australian ducklings from 0 to 2 weeks and 3 to 8 weeks of age respectively.