# The blood transcriptome of musk deer under heat stress condition reveals the regulatory mechanism of genes to maintain homeostasis metabolism

## TL;DR

This study explores how heat stress affects the blood metabolism and immune system of forest musk deer, revealing key genes and pathways involved in their response.

## Contribution

The study identifies novel immune-related genes and metabolic pathways in forest musk deer under heat stress, providing insights for their scientific breeding.

## Key findings

- Heat stress significantly increases cortisol and corticosterone levels in forest musk deer during high THI periods.
- Genes like JAK1, AP3B1, and FKBP15 are significantly up-regulated in response to heat stress, indicating immune system activation.
- Heat stress disrupts metabolism and immune function, particularly impacting immunity and protein metabolism pathways.

## Abstract

Heat stress has a significant adverse impact on both livestock and poultry production, posing a considerable challenge to the artificial breeding of forest musk deer. However, there is a lack of studies on the heat stress of forest musk deer, so it is necessary to understand the effects of temperature and humidity index (THI) variation on these animals.

In according to the local climate characteristics, blood samples were collected during four periods (April, June, July and August) for biochemical indicators and transcriptome sequencing. The results showed that blood cortisol and corticosterone concentrations increased significantly in July (THI = 74.89, P < 0.05). Moreover, Na+ concentration exhibited a negatively correlated with THI (r = -0.959, Pr = 0.041). Blood urea nitrogen (BUN) concentration in July (G3) was significantly lower than that in April (G1) and June (G2) (P < 0.05). The total antioxidant capacity (T-AOC) in July was significantly decreased (P < 0.05), and the creatine kinase (CK) was significantly higher than that in April and August. There was a significant positive correlation between immunoglobulin G (IgG) and THI (r = 0.999, Pr = 0.001) attributable to the significant increase of TNF-α in July (P < 0.05). The transcriptomic comparison between G1 and G3 revealed the largest number of differentially expressed genes (DEGs) (6410 up-regulated and 472 down-regulated). Among them, JAK1, AP3B1 and FKBP15 were the most significantly up-regulated immune-related genes in response to heat stress. Trend analysis indicated that the pathways related to immunity and protein metabolism were particularly impacted by heat stress.

Research indicates that heat stress disrupts the normal metabolism of forest musk deer and adversely affects their immune system, which is attributed to the THI exceeding the threshold that forest musk deer can tolerate. The findings of this study provide valuable data support for the scientific breeding of captive forest musk deer and enhance the understanding of the immune dynamics of ruminants under heat stress.

The online version contains supplementary material available at 10.1186/s12864-025-11577-y.