Abstract:

Objective: This study aimed to investigate the effect of different doses and durations of administration of
capsaicinoids on intestinal health in rats. Methods: A total of 96 Sprague-Dawley (SD) rats were stochastically divided into
three batches with 32 in each batch, each of which was further randomly divided into four groups by body weight with 8
in each group. Under normal feeding conditions, these four groups of rats were administered daily with capsaicinoids at
doses of 0 (CON), 4 (low dose, LD), 8 (moderate dose, MD), and 12 mg/(kg·d) (high dose, HD) in soybean oil solution,
respectively. Food intake was recorded daily. After being fed for 4, 8 and 12 weeks, the rats were executed and their
cecum samples were collected for the determination of cecal contents, cecal wall, free ammonia, pH, short chain fatty acids
(SCFA) and microorganisms to evaluate the intestinal health status. Results: After being fed for 4 weeks, the number of
bifidobacteria in all three dose groups was increased significantly whereas the number of Escherichia coli (E. coli) in the
LD group was significantly decreased. After feeding for 8 weeks, body weight was significantly decreased and lactic acid
bacteria were significantly increased in these dose groups, the cecal area was significantly decreased in the MD and HD
groups, and the number of anaerobes was significantly increased but the number of E. coli was significantly decreased in the
HD group. After being fed for 12 weeks, the body weight and cecal area were significantly decreased and pH was increased
significantly, the concentrations of acetic acid and propionic acid were significantly decreased. Anaerobic bacteria and
enterococci were significantly increased in the three dose groups, and lactic acid bacteria were significantly decreased in both
MD and HD groups. Conclusion: Short-term administration of capsaicinoids can improve the intestinal health but long-term
administration will cause serious damage to the intestinal health.

Key words: chili alkaloids, intestinal health, free ammonia, short chain fatty acids, microbiology