Exploring the Potential Effects of Soybean By-Product (Hulls) and Enzyme (Beta-Mannanase) on Laying Hens During Peak Production.

Simple Summary: This study investigated the effect of soybean hulls (SHs) and enzymes (β-mannanase) on the egg quality, serum biochemistry, nutrient digestibility, digesta viscosity, feces consistency, and intestinal histomorphology of golden-brown laying hens during peak production. Different diets containing different levels of SHs and enzymes were fed to the birds for four weeks, and the results showed a significantly improved gut villus width, height, crypt depth, and surface area in the 3% SH and 0.03 g/kg enzyme group than in the remaining groups. This combination also enhanced the dry matter, crude protein, crude fiber, and crude fat digestibility and reduced total cholesterol and LDL levels. Egg quality, digesta viscosity, and feces consistency were not affected. Overall, adding 3% of SHs and 0.03 g/kg of enzymes (β-mannanase) to the feed may help enhance laying hens' gut health and nutrient digestibility, lowering cholesterol and LDL levels without affecting the egg quality indices. This study determined the interaction between soybean hulls (SHs) and enzymes (β-mannanase) to improve the sustainability and efficacy of feeding programs for laying hens during peak production while ensuring the best health and efficiency. In a completely randomized design (CRD), 200 golden-brown hens were fed for four weeks (33 to 36 weeks) and randomly distributed into four groups, each containing four replicates of ten birds, with one group receiving a control diet (P0) and the others receiving diets that contained four combinations of SHs and enzymes (ENZs). e.g., 3% SHs and 0.02 g/kg ENZs (P1), 3% SHs and 0.03 g/kg ENZs (P2), 9% SHs and 0.02 g/kg ENZs (P3), and 9% SHs and 0.03 g/kg ENZs (P4). Although most egg quality measures remained similar, the P2 group showed enhanced (p = 0.630) egg weight, albumen weight, and height. Moreover, the P2 group improved gut (p < 0.05) shape by increasing villus width, height, crypt depth, and surface area throughout intestinal sections, while the P4 group markedly improved total cholesterol and LDL (p = 0.022) levels. The P1, P2, and P4 groups exhibited a significant enhancement in dry matter (p = 0.022) and crude fiber (p = 0.046) digestibility, while the P2 group demonstrated superior crude protein digestibility (p = 0.032), and the P1 and P2 groups showed increased crude fat digestibility compared to the other groups. In conclusion, adding 3% of SHs and 30 mg/kg of ENZs (β-mannanase) to the feed may help laying hens, enhance gut health and some egg quality indices, and decrease blood cholesterol and LDL levels without compromising nutrient digestibility. [ABSTRACT FROM AUTHOR]