Cereal type but not the length of adaptation to experimental diets influenced dietary metabolisable energy for broilers
A total of 288 broilers were used to study the influence of length of adaptation to diet on metabolisable energy (AME) determined for diets based on different cereals. At day 14 of age, the birds were allocated to 12 dietary treatments (a 4×3 factorial treatment arrangement) with each treatment having 8 replicates and 3 birds per replicate. The factors were three diets based on wheat, wheat plus maize or wheat plus rye and four lengths adaptation to dietary treatments (14, 10, 7 or 4 days). Birds started receiving the experimental diets either on day 14, 18, 21 or 24 of age and excreta were collected from all the birds on day 28 and chemically analysed. Digestibility was calculated using the index method and the metabolisable energy of maize and rye were determined using the substitution method. There were no diet × adap-tation length interactions on any response. The diet dry matter and energy retention was highest (P < 0.05) in wheat-maize diet but AME was lowest (P < 0.05) in wheat-rye diet. There was no effect of length of adaptation to dietary treatments on diet dry matter or energy utilisation. Metabolisable energy of maize was greater (P < 0.01) than rye but cereal AME determined by substitution was not influenced by length of adaptation to diet. It was concluded that AME of diet was influenced by cereal type but not the length of adaptation to diets and hence adaptation length as short as 4 days could be used when determining AME of diets or cereals for broilers.
Other Titles/Title of Conference
20th European Symposium on Poultry Nutrition, Prague, Czech Republic