# Effects of Zanthoxylum bungeanum Leaves on Production Performance, Egg Quality, Antioxidant Status, and Gut Health in Laying Hens

## TL;DR

This study shows that Zanthoxylum bungeanum leaves can improve egg quality and hens' health when added to their feed, turning agricultural waste into a useful resource.

## Contribution

The study quantifies the energy value and health benefits of Zanthoxylum bungeanum leaves in laying hens for the first time.

## Key findings

- ZBL provided usable energy and did not harm egg production when replacing low-energy feed ingredients.
- ZBL improved egg quality, antioxidant status, and gut health in laying hens.
- ZBL increased beneficial gut bacteria and short-chain fatty acids in the cecum.

## Abstract

Laying hens need good quality feed to produce safe, nutritious eggs, but conventional feeds are becoming more expensive and compete with human food. At the same time, large amounts of Zanthoxylum bungeanum leaves (ZBL) are discarded each year, which come from Zanthoxylum bungeanum, whose fruits are widely used as a pungent spice in Chinese cuisine. In this study, we first measured how much usable energy ZBL can provide for hens. Diets containing different levels of ZBL were then fed to laying hens, and the following were monitored: egg production, egg quality, blood health markers, the ability to resist oxidative damage, gut structure, and gut bacteria. We found that ZBL provided relatively low energy but did not harm egg production when it replaced part of a low-energy-feed ingredient. In contrast, it improved egg white and yolk quality, boosted the antioxidant and immune status of laying hens, improved the structure of the small intestine, and increased beneficial fermentation products in the cecum. These results suggest that using ZBL in layer diets can turn agricultural waste into a valuable feed resource that supports both egg quality and hens’ health.

Zanthoxylum bungeanum leaves (ZBL) are a phytogenic feed resource, but their energy value and functional effects in laying hens are not well defined. Two experiments were conducted. In Exp. 1, 96 healthy 38-week-old Roman Pink laying hens were allotted to either a control diet or a diet containing 5% ZBL (eight replicates, six hens per replicate) to determine apparent metabolizable energy (AME) using an indicator method (7 d adaptation, 3 d collection). The AME and nitrogen-corrected AME of ZBL were 5.46 and 5.33 MJ/kg, respectively. In Exp. 2, 832 healthy 41-week-old hens were randomly assigned to diets supplemented with 0, 1%, 2%, or 3% ZBL (8 replicates, 26 hens per replicate) for 8 weeks after 1 week adaptation. Dietary ZBL at 1% to 3% did not affect production performance (p > 0.05), but increased albumen height linearly (p < 0.05) and improved yolk color at 2% and 3% (p < 0.05). ZBL increased serum albumin (p < 0.05) with a linear tendency (p = 0.065), and elevated serum IgA and IgM linearly (p < 0.05). Serum total antioxidant capacity and total superoxide dismutase were increased (p < 0.05) with significant linear and quadratic responses (p < 0.05), while serum malondialdehyde was reduced (p < 0.05). In the liver, 3% ZBL increased total antioxidant capacity (p < 0.05), hepatic catalase activity was decreased in all ZBL groups (p < 0.05), and hepatic malondialdehyde was reduced (p < 0.05). Cecal acetate increased linearly (p < 0.05), and propionate and butyrate increased with both linear and quadratic dose responses (p < 0.05). ZBL improved small intestinal morphology, especially duodenal villus height (p < 0.05). Gut microbiota was remodeled, with a marked reduction in norank_o__WCHB1-41 and increases in Ruminococcus, Pseudoflavonifractor, and several Coriobacteriales and Erysipelatoclostridiaceae taxa. Overall, ZBL provides usable energy and, at 2–3% inclusion, enhances egg quality, antioxidant status, humoral immunity, short-chain-fatty-acid production, and intestinal health without compromising laying performance.