(P03-089-23) Essential Oil Drives Appetite Improvement Through Crosstalk Activated by Gut -Ghrelin – Hypothalamic AgRP/NPY Neurons

Objectives: Stress is known to cause severe adverse effects in the intestine and further induce the loss of appetite. Essential oil (EO) is considered as a promising dietary supplement in the breeding industry, which not only improve intestinal health, but also increase food intake. Phytogenic compounds have been reported to improve feed intake, especially when combined with EOs. Pro-opiomelanocortin (POMC) and neuropeptide Y (NPY) are specifically expressed in neuronal populations in the arcuate nucleus (ARC) of the hypothalamus, allowing the ARC to act as a control center for feeding. Herein, we hypothesized that essential oils improve intestinal health and appetite in nursery pigs by interacting with intestinal chemoreceptors; the mechanism of regulating appetite may be related to the activation of appetite-related hormones on AgRP/NPY neurons in the ARC of the hypothalamus.

Methods: EOs (containing 5% cinnamaldehyde, 5% carvacrol, and 0.8% thymol) were added to the diet of nursery piglets for 42 days. Thereafter, the influence of EOs on regulating intestinal homeostasis and the underlying mechanism and promoting appetite was explored.

Results: EOs supplementation increased feed intake and improved intestinal health of piglets undergoing early stress, which was manifested by improved intestinal morphology and structure, improved intestinal mechanical and chemical barrier function. EOs supplementation also dramatically remodeled the gut microbiota in nursery pigs subjected to early life stress, and increased abundance of beneficial bacteria (such as Lactobacillus, Prevotella and Megasphaera). Additionally, we found that the intestinal ectopic olfactory and taste receptors were activated, and the expression of transporters increased in piglets with EOs supplement. Besides, EO supplementation altered the level of gastrointestinal hormones in circulation, especially increased the level of ghrelin.

Conclusions: Overall, our study suggests that EOs are an intestinal health regulator and appetite booster, which improve intestinal health and remodel intestinal microbial communities, further regulate GPCR and gastrointestinal hormones.

Funding Sources: This study has received assistance from National Natural Science Foundation of China (No. 32172932).<br>*Corresponding author: Prof. Jin-Long Li. E-mail address: Jinlongli@neau.edu.cn