# Effects of Dietary Cinnamaldehyde Supplementation on Growth Performance, Serum Antioxidant Capacity, Intestinal Digestive Enzyme Activities, Morphology, and Caecal Microbiota in Meat Rabbits

## TL;DR

Adding cinnamaldehyde to rabbit feed improves growth, digestion, and gut health, making it a good alternative to antibiotics.

## Contribution

This study identifies 150 mg/kg cinnamaldehyde as the optimal dose for enhancing meat rabbit production.

## Key findings

- Rabbits fed 150 mg/kg cinnamaldehyde had 11.73% longer duodenal villi and 62% lower diarrhoea rates.
- Cinnamaldehyde increased fibre-fermenting Oscillospiraceae by 38% and reduced Ruminococcaceae by 27%.
- Optimal cinnamaldehyde dose improved growth performance, enzyme activity, and microbial diversity.

## Abstract

The restriction of antibiotic growth promoters (AGPs) in animal farming has driven the search for sustainable alternatives. Cinnamaldehyde (CA), a phytogenic compound, shows promise due to its antimicrobial, antioxidant, and gut health benefits. This study aimed to investigate the effects of dietary CA supplementation on the growth performance, serum antioxidant capacity, intestinal digestive enzyme activities, morphology, and caecal microbiota of meat rabbits. Our findings revealed that dietary CA supplementation not only exerted positive effects on the growth performance of the test animals but significantly improved intestinal digestive enzyme activities, intestinal morphology, and caecal microbiota regulation, reducing diarrhoea and mortality rates. Further, the diet containing 150 mg/kg CA showed optimal effects. Therefore, the use of CA as an efficient and sustainable antibiotic to promote meat rabbit production is highly recommended.

Cinnamaldehyde (CA) is a potential substitute for antibiotic growth promoters in animal breeding. In this study, we investigated its effects as a dietary supplement on growth performance, serum antioxidant capacity, intestinal digestive enzyme activities, intestinal morphology, and caecal microbiota in meat rabbits. Weaned meat rabbits (n = 450) were randomly assigned to five groups, Groups A, B, C, D, and E, and fed 0, 50, 100, 150, and 200 mg/kg CA diets, respectively, for 47 days. Biological samples including serum (antioxidants), duodenal/caecal content (enzymes), intestinal tissue (morphology), and caecal digesta (microbiota) were collected at day 47 postweaning for analysis. Groups C and D showed significantly higher final body weights than Group A, with Group D (150 mg/kg CA) demonstrating superior growth performance including 11.73% longer duodenal villi (p < 0.05), 28.6% higher microbial diversity (p < 0.01), and 62% lower diarrhoea rate versus controls. Digestive enzyme activity as well as serum antioxidant capacity increased with increasing CA dose, Microbiota analysis revealed CA increased fibre-fermenting Oscillospiraceae (+38%, p < 0.01) while reducing Ruminococcaceae (−27%, p < 0.05). Thus, dietary CA supplementation at 150 mg/kg was identified as the optimal CA dose for improving meat rabbit production. These findings highlight CA as a functional feed additive for promoting sustainable rabbit production.