Effect of vegetable by-products on egg protein quality and coefficients of apparent absorption from laying hen diets

The in vivo feeding trial was conducted on 6 weeks with 126 Tetra SL laying hens, 56-week old, assigned to 3 groups. The layers were housed in an experimental hall with controlled microclimate, in three-tier digestibility cages (2 layers per cage) which allowed the daily recording of the feed intake and excreta. All hens received a conventional compound feed (C), based on corn and soybean meal, which contained 2750 kcal/kg metabolizable energy and 17.50% crude protein. Each experimental group had as supplement one fat and one antioxidant vegetal source, rapeseed meal and grapeseed meal (RGM) respectively flaxseed meal and buckthorn meal (FBM). The balance study was conducted for 5 days, on the last experimental week. During this period, average weights from each cage (6 samples per group) of feed and excreta were recorded, collected and sampled for: dry matter (DM), crude protein (CP), ether extractives (EE), crude fibre (CF) ash and amino acids determinations from feeds. The layers from FBM group had significantly (P