5-Hydroxytryptophan Suppresses the Abdominal Fat Deposit and Is Beneficial to the Intestinal Immune Function in Broilers

Abstract

Background: Serotonin (5-HT), a monoaminergic neurotransmitter, involves in the regulation of many physiological functions. In the present study, the effects of 5hydroxytryptophan (5-HTP), the precursor of 5-HT, on lipid metabolism and intestinal immune function in broiler chickens were investigated in chickens. Methods: Two hundred broilers were divided randomly into two groups and fed separately with a corn-soybean basal diet (CD) or the basal diet supplemented with 0.2% 5-HTP. Results: The results showed that 5-HTP reduced (P < 0.05) feed intake and the abdominal fat pad weight. 5-HTP treatment tended to upregulate the mRNA level of adiponectin receptor 1 (ADP1R) and ADP2R in abdominal fat but had no significant influence on their protein levels (P > 0.05). In 5-HTP-chickens, lipopolysaccharide exposure decreased secretory immunoglobulin A (sIgA) concentrations in serum and the duodenal contents. Expression of mRNA encoding interleukin (IL), tumor necrosis factorα (TNF-α), and transforming growth factor-β (TGF-β) decreased after 5-HTP treatment; however, LPS increased expression significantly in 5-HTP-treated chickens compared with CD chickens. In 5-HTP-chickens, the phosphorylation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) were reduced, but the phosphorylation of ribosomal p70S6 kinase (p70S6K) was increased in the duodenum. Conclusion: In summary, the result suggests that dietary 5-HTP supplementation reduces accumulation of abdominal fat and is beneficial to intestinal immune function.

Allicin Promotes Glucose Uptake by Activating AMPK through CSE/H2S‐Induced S‐Sulfhydration in a Muscle‐Fiber Dependent Way in Broiler Chickens

“…[ 23 ] In chickens, the activated AMPK pathway is involved in 5‐hydroxytryptophan‐regulated lipid metabolism and adiponectin‐induced glucose uptake in the myoblasts. [ 24,25 ] This suggests the positive regulatory effect of the AMPK pathway on energy metabolism in chickens. Therefore, exploring the underlying mechanisms of glucose metabolism in chicken skeletal muscle would provide novel perspectives on the metabolic pathways in chickens, as well as provide valuable insights into their physiology compared to mammals.…”