Studies on the metabolizable energy content of ground full-fat flaxseed fed in mash, pellet, and crumbled diets assayed with birds of different ages

Four experiments were carried out to determine the AME(n) of ground flaxseed in chickens of different ages and to study the effect of feeding flaxseed in pelleted or crumbled diets on flaxseed AME(n). A corn-soybean meal basal diet was prepared, in which the energy-yielding ingredients were substituted with ground flaxseed at 5, 10, 15, or 20%. Experiments 1, 2, and 3 consisted of these five dietary treatments replicated six times using 9-d-, 6-wk-, and 79-wk-old birds, respectively. A total collection procedure was used to measure diet AME(n), and linear regression analyses were used to calculate the AME(n) value of flaxseed for birds at different ages. Experiment 4 involved birds fed either a basal, or a 10% ground flaxseed diet prepared as mash, pellets, or crumbles. The flaxseed AME(n) values obtained with 9-d- and 6-wk-old chickens were 2,118 and 2,055 kcal/kg, respectively. These values contrast with those of Experiments 3 and 4, in which mature roosters were fed mash diets with AME(n) values of 3,560 and 3,654 kcal/kg, respectively. In Experiment 4, a significant improvement in flaxseed AME(n) was observed when diets were pelleted or crumbled (4,578 and 4,277 kcal/kg, respectively). We concluded that the difference in AME(n) of flaxseed observed in young birds vs. that found in mature birds was likely due to a greater tolerance of the latter to flaxseed, with less evidence of diarrhea. Feeding flaxseed in pellet or crumbled diets can significantly increase AME(n) value.