Ark NE1 calculations for ingredients in broiler diets

摘要

The continuous development of accurate and precise methods for measuring energy is vital in the modern poultry industry. Three experimental iso-caloric (analysed 3,200 kcals) diets with increasing amino acid concentration were fed broilers from d 22-d42. The three finisher (d-22-42) diets were formulated based on a balanced ideal protein (analysed 3.3 gdLys/Mcal, 3.9 gdLys/Mcal, 4.7 gdLys/ Meal) with amino acids formulated to ratio with gdLys. Heat production (HP) was measured for 24 h period usingrespiratory chambers. After HP measurement, fasting heat production (FHP) was measured for 24 h. Heat increment (HI) was determined: (HI) = HP - FHP. Body composition was measured on d 22 and d 42 by dual energy X-ray absorptiometry (DEXA) to determine net energy of gain: (NEg) = protein grams x 5.66 + fat gain grams x 9.35). Two NE equations were compared: Classic NE (kcals) = ME-HI and Ark NE (kcals) = NEg + NEm, where NEm (net energy maintenance) = HP - HI. The calorie efficiency (%) was calculated as NE/AMEn x 100. Calorie difference (CD) between the two equations was calculated: CD=Ark NE (kcals) - Classic NE (kcals). No differences between diets were found for HP, HI and NEm. NEg (P=0.009) was significantly different between diets with increasinggdLys/Mcal producing more NEg (kcals). There was a significant increase (PO.0001) in fat gain (g/b) for the same lower amino acid diets. The CD between Ark NE vs Classic NE increased from 700 kcals to approximately 1,200 kcals as dietary amino acids increased. Overall, the calorie efficiency was over 100% for Ark NE. The Ark NE system supports increasing protein calorie gain compared to the Classic NE system favoring fat calorie deposition.