Impact of Enzyme-Supplemented Diets with Varying Metabolizable Energy Levels on Growth Performance, Egg Quality, and Blood Parameters in Laying Hens

This study examined the impact of reducing dietary metabolizable energy (ME) and supplementing with exogenous enzymes on performance, egg quality, and blood parameters of laying hens from 42 to 56 weeks of age. Four hundred and thirty-two laying hens were divided into twelve groups with six replicates (6 birds/replicate) and fed diets with varying levels of ME (control, 2.5% lower, or 5% lower) with or without a combination of two types of enzymes (Avizyme (1502) and Phyzyme (XP)). Hens fed diets with 2.5% lower ME exhibited reduced feed intake (FI), egg mass (EM), and a poorer feed conversion ratio (FCR) compared to the control group (P < 0.05). Reducing dietary ME by 5% did not significantly affect FI, egg production (EP), FCR and EM (P > 0.05). Enzyme supplementation generally improved FI and FCR at some points, but separate addition showed a greater benefit compared to combining them (P < 0.05). The use of enzymes resulted in a decrease in the Haugh unit compared to the control diet (P < 0.05). Additionally, the decrease in the energy content of the diet reduced the egg shape index (P < 0.05). Furthermore, the simultaneous addition of enzymes and decrease in energy increased the blood uric acid levels (P < 0.05). This study demonstrates that reducing metabolizable energy in corn-soybean meal diets for laying hens negatively impacts performance, with enzyme supplementation failing to fully compensate for these detrimental effects.