Attenuating effect of melatonin on lipopolysaccharide-induced chicken small intestine inflammation

Area of Science:

• Gastroenterology
• Immunology
• Animal Science

Background:

• Melatonin (MEL) is found in the mammalian intestine and can alleviate colitis in rodents.
• Lipopolysaccharide (LPS) is known to induce intestinal inflammation.

Purpose of the Study:

• To investigate the effect of dietary MEL on LPS-induced intestinal inflammation in newly hatched chickens.
• To explore the underlying mechanisms of MEL's protective effects.

Main Methods:

• Chicks were fed a diet supplemented with MEL (12.5 mg/day) from day 1 to 10.
• LPS (10 mg/kg BW, i.p.) was injected on day 10 to induce inflammation.
• Gene expression (IL-6, IL-4, caspase-3, TNF-α, MUC2, TLR4), cell populations (TUNEL+, goblet, PCNA+), and IgA production were analyzed in the duodenum.

Main Results:

• LPS treatment increased inflammatory markers (IL-6, caspase-3, TNF-α) and apoptosis, while decreasing goblet cells, PCNA+ cells, IgA, and MUC2 expression.
• MEL pre-feeding significantly alleviated duodenal inflammation, reducing inflammatory cytokine mRNA expression and epithelial apoptosis.
• MEL attenuated LPS-induced changes, enhancing IgA production and PCNA+ cell populations, and down-regulating TLR4 mRNA expression.

Conclusions:

• Dietary MEL effectively attenuates LPS-induced duodenal inflammation in chicks.
• MEL exerts protective effects by down-regulating inflammatory cytokines, promoting epithelial cell proliferation, improving the immunological barrier, and inhibiting apoptosis.
• The Toll-like receptor 4 (TLR4) pathway is implicated in MEL's anti-inflammatory actions in the chick duodenum.