Effects of Dietary Inclusion of Roasted Full-Fat Soybean on Egg Production and Quality, Hematological Parameters, and Cholesterol Level in Layer Chickens

The scarcity and high costs of poultry feed ingredients, such as soybean meal (SBM), present significant challenges for modern poultry production systems in Ethiopia. To explore potential alternatives, this study evaluated the effects of varying inclusion levels of roasted full-fat soybean (FFSB) in layer diets on productive performance, egg quality traits, and selected blood parameters. A 12-week feeding trial was conducted using 120 Bovans Brown hens aged 34-46 weeks, with an average initial body weight of 1.44 ± 0.01 kg. The hens were randomly assigned to five dietary treatment groups (0%, 10%, 15%, 20%, and 25% FFSB), each replicated three times with eight hens per replicate. The control diet contained 20% SBM for comparison. The results showed that hens in the control group exhibited significantly higher hen-day egg production (89.72%), egg mass (54.28 g/hen/day), and body weight gain (314 g) compared with those fed diets containing different inclusion levels of FFSB. However, no significant differences in egg production were observed among the groups fed diets containing different inclusion levels (10-25%) of FFSB. The group fed 10% FFSB exhibited a higher egg mass (38.44 g/hen/day) than those receiving 15% and 25% inclusion levels. The feed conversion ratio (FCR) increased with higher levels of FFSB inclusion, with the 25% FFSB group showing a significantly higher FCR (3.37) compared to the control group (2.06). Full-fat soybean inclusion had no significant influence on most egg quality traits, nor on hematological indices or serum cholesterol levels. The findings indicated that FFSB inclusion in layer feeds at levels up to 25% did not compromise egg quality or hen health. Although higher FFSB inclusion lowered feed costs, reduced egg production offset these savings, making full substitution of SBM economically unprofitable. Keywords: Diet, Egg production, Egg quality, Full-fat soybean, Inclusion level, Layer