Dietary Supplementation with Zanthoxylum bungeanum Seed Cake and Meal Improves the Productive Performance and Antioxidant Capacity of Laying Hens

The objective of this paper was to examine the effects of differing levels of dietary Zanthoxylum bungeanum seed cake and meal (ZBS) on the productive performance, egg quality, gut microbiota and liver metabolomics of laying hens. In total, 1280 healthy Lohmann Pink laying hens (age, 36 weeks) were randomly assigned to four treatment groups: control (CON), 1% ZBS, 2% ZBS, or 3% ZBS. The trial lasted for eight weeks. The results indicated that compared to the CON group, the 3% ZBS group had a higher egg production during weeks 5–8 and 1–8 (p < 0.05). However, the feed-to-egg ratio and egg breakage rate during weeks 1–8 was lower in the 2% ZBS group and 3% ZBS group compared to the CON group (p < 0.05). Adding different levels of ZBS to the diet significantly increased egg production, reduced the feed-to-egg ratio, and reduced the feed intake of weeks 5–8 in laying hens (p < 0.05) with both effects exhibiting a linear relationship as the addition level increased (p < 0.05). Compared to the CON group, supplementing the diet with 2% or 3% ZBS significantly increased T-AOC levels in the liver and serum, as well as T-SOD enzyme activity, but it significantly decreased the MDA level in the serum (p < 0.05). The addition of ZBS has been demonstrated to induce alterations in the microbial composition of the cecum in laying hens. The key metabolic pathways and key metabolites are glycerophospholipid metabolism and magnoflorine, respectively. In conclusion, the supplementation of diets with ZBS has been demonstrated to significantly enhance the production performance and antioxidant capacity in laying hens. The optimal supplementation level was 3% ZBS.