# Investigating the Impact of Fasting and Refeeding on Blood Biochemical Indicators and Transcriptional Profiles in the Hypothalamus and Subcutaneous Adipose Tissue in Geese

## TL;DR

This study examines how fasting and refeeding affect blood chemistry and gene activity in geese, revealing metabolic and energy regulation changes.

## Contribution

The study identifies specific genes and metabolic pathways in geese hypothalamus and adipose tissue affected by fasting and refeeding.

## Key findings

- Fasting increases free fatty acids and glucagon while decreasing triglycerides, leptin, and insulin in geese blood.
- Fasting downregulates fatty acid synthesis genes (LPL, SCD, ACSL1) and upregulates PLIN2 in subcutaneous adipose tissue.
- Fasting alters hypothalamic gene expression, upregulating NOG, GABRD, and IGFBP-1 while downregulating POMC.

## Abstract

This study explores how geese respond to fasting and subsequent refeeding by analyzing changes in blood chemistry and gene activity in the hypothalamus and subcutaneous adipose tissues. After 24 h of fasting, geese’s blood levels of key substances such as fatty acids, glucagon, triglycerides, leptin, and insulin changed noticeably. The research also identified specific genes in the hypothalamus and subcutaneous adipose tissue that are influenced by fasting, providing insight into how geese regulate energy and maintain metabolic balance in response to changes in food intake.

Fasting and refeeding systems can cause significant short-term fluctuations in nutrient and energy levels, triggering adaptive physiological responses in animals. This study examines the effects of fasting and refeeding on blood biochemical indicators and transcriptional profiles in the hypothalamus and subcutaneous adipose tissue of geese. Biochemical assays reveal that fasting significantly increases levels of free fatty acids and glucagon, while reducing concentrations of triglycerides, leptin, and insulin. Transcriptomic analyses identify a complex transcriptional response in both the hypothalamus and subcutaneous adipose tissue, affecting several metabolic pathways and key genes associated with feed intake and energy metabolism. In subcutaneous adipose tissue, fasting downregulates genes involved in fatty acid synthesis (LPL, SCD, and ACSL1) and upregulates PLIN2, a gene promoting lipid droplet degradation. Fasting affects a variety of metabolic pathways and critical genes in the hypothalamus, including Apelin, insulin, and mTOR signaling pathways. After fasting, the mRNA expression of NOG, GABRD, and IGFBP-1 genes in the hypothalamus are significantly upregulated, while proopiomelanocortin (POMC) gene expression is markedly downregulated. This study highlights the intricate biological responses to nutritional changes in geese, which adds to our understanding of energy balance and metabolic regulation in avian species.