Dietary Zanthoxylum bungeanum Leaves Influence Meat Quality, Caecal Microbiota, Serum Metabolome and Muscle Transcriptome in Growing Rabbits

This study evaluated the effects of dietary supplementation with 5% Zanthoxylumbungeanum leaf (ZBL) on growth performance, slaughter traits, meat quality, caecal microbiota, serum metabolome, and muscle transcriptome in rabbits. A total of 108 male New Zealand rabbits (60 days old) were randomly assigned to two groups (nine replicates/group; six rabbits/replicate) and fed either a basal diet (CON) or a diet in which 5% wheat bran was replaced with 5% ZBL for four weeks. Growth and slaughter performance did not differ (p > 0.05). ZBL reduced drip loss and cooking loss, enhanced antioxidant capacity, reduced specific saturated (C16:0), and unsaturated (C18:1 n-9 cis) fatty acids in leg muscle (p < 0.05), and the nutritional significance of these fatty acid changes remains unclear. ZBL also altered the levels of several volatile and non-volatile compounds in serum and muscle. It increased caecal abundance of norank_f_Lachnospiraceae and Anaerofilum, elevated serum metabolites (oleuropein, 3-coumaric acid), and upregulated meat quality-related genes (NR3C2, PDZRN3) in leg muscle (p < 0.05). Correlation analyses revealed that the observed changes in meat quality were closely associated with alterations in gut microbiota, serum metabolome, and muscle transcriptome. These findings suggest that dietary 5% ZBL does not compromise growth performance and is associated with changes in rabbit meat quality, which is associated with coordinated alterations in the gut microbiota, serum metabolome, and muscle transcriptome.