Response of dual-purpose and layer hybrid hens in yield and quality of eggs, carcass and meat to a diet composed of food industry by-products and grain legumes: a pilot study

In common layer hybrid nutrition, feedstuffs potentially human edible and soybean-based feeds cover most of the diet. The use of alternative energy and protein sources is limited due to insufficient nutrient density. We investigated whether less demanding dual-purpose poultry would better tolerate a diet composed of food industry by-products and grain legumes. Hen types investigated were Lohmann Brown Plus (LB, layer hybrid; n = 10), Lohmann Dual (LD, a dual-purpose hybrid; n = 10), Belgian Malines (BM) and Schweizerhuhn (CH) (both traditional dual-purpose breeds; n = 9). Hens were in late stage of lay. In a cross-over design, hens received for 4 weeks a common layer diet (C; 11.5 MJ/kg N-corrected metabolizable energy (ME) and 4.3 g methionine/kg) or a diet exclusively composed of by-products and grain legumes (B; 10.4 MJ/kg ME and 2.4 g methionine/kg). Subsequently they stayed for another 8 weeks on the respectively other diet until slaughter. Feed efficiency (g feed/g egg) was better in LB (2.7) and LD (2.8) than CH (4.6) and BM (5.2). Body and carcass weights (kg) were highest in BM (3.4/2.0), followed by CH (2.6/1.6), and lowest in LB and LD (both 1.9/1.1). Feed efficiency was higher in diet C than B, as was egg weight (g; C: 63; B: 59). Diet B adversely affected carcass weight, breast meat yield and meat shear force, but not egg quality. Feed intake (g/day) declined in LB from 121 to 65 and in LD from 102 to 80 when switching from diet C to B. With diet B, laying performance declined from 92 to 53% in LB and from 70 to 50% in LD. Both traits remained unaffected in BM and CH, showing that diet B was sufficient only in these two hen types in late laying. Further studies have to confirm these results with more replicates and different by-product diets.