A comparison of grinding processes and wet feeding of wheat-based diets on AME, production, and gastrointestinal tract development of broiler chicks

This experiment studied the effect of grind mill type [hammer (HM) or attrition (AM)], grind size (5.6 mm 4.8 mm, and 2.4 mm) and wheat type [Durum or Hard Red Spring (HRS)] on the performance, energy retention (AME), and the gut development of broilers fed these diets with or without 1.2 g water(-1) g dry feed added. Twenty-four dietary treatments (2 grind types x 3 grind sizes x 2 wheat types x wet or dry feeding) were each fed to four cages of six male broilers from I to 17d of age. Wet diets were prepared daily. Feeding diets with water increased 17 d body weight and feed intake of broilers compared with feeding the diets dry. Body weight and feed intake of broilers fed the HM diets were greater than those of broilers fed diets containing wheat processed by AM. Feed intake and FCR with HRS-based diets were higher than those for Durum-based diets. The AME for Durum was higher than for HRS and the ME efficiency (kcal g(-1) BW) was greater, indicating a lower efficiency. The AME intake of HM ground wheat was higher than for that for wheat ground with the AM. The type of grinding, the wheat type, and the addition of water all affected the length and weight of the digestive system, likely through their effects on the rate of water absorption and passage through the gut. Particle size did not affect any measurement. Hammer milling produced a uniform particle size and less fines and may be better suited for processing wheat in broiler diets.