# Assessing the Impacts of Different Levels of Nano-Selenium on Growth Performance, Serum Metabolites, and Gene Expression in Heat-Stressed Growing Quails

## TL;DR

This study shows that adding nano-selenium to the diet of heat-stressed quails improves their growth and reduces oxidative stress.

## Contribution

The study demonstrates that low-dose nano-selenium supplementation ameliorates heat stress effects in quails through gene expression modulation.

## Key findings

- Adding 0.2 mg/kg nano-Se improved growth performance and restored blood oxidative status in heat-stressed quails.
- Low-dose nano-Se downregulated inflammatory genes and upregulated antioxidant genes in heat-stressed quails.
- High-dose nano-Se (0.5 mg/kg) increased inflammatory gene expression and reduced antioxidant markers.

## Abstract

Nanotechnology offers a unique opportunity to incorporate nanoparticles as alternative sources of trace minerals in animal diets. The purpose of this study was to investigate the effects of applying different concentrations of nano-Se on the growth performances, carcass features, serum components, and gene expressions in heat-stressed Japanese quails. The performance of heat-stressed quails was greatly enhanced by the addition of nano-Se, particularly at the level of 0.2 mg/kg of feed, which also repaired the blood oxidative state. The 0.2 nano-Se-exposed group showed a substantial downregulation of the IL-2, IL-4, IL-6, and IL-8 genes and an upregulation of the SOD and GPX genes in comparison to the heat stress group, indicating that nano-Se had an ameliorative effect on heat stress. It was determined that modest levels of nano-Se in growing heat-stressed quails yield the best results, and its supplementation can be viewed as a protective management strategy in Japanese quail diets to lessen the adverse effects of heat stress.

Nano-minerals are employed to enhance mineral bioavailability thus promoting the growth and well-being of animals. In recent times, nano-selenium (nano-Se) has garnered significant attention within the scientific community owing to its potential advantages in the context of poultry. This study was conducted to explore the impact of using variable levels of nano-Se on the growth performance, carcass characteristics, serum constituents, and gene expression in growing Japanese quails under both thermoneutral and heat stress conditions. A randomized experimental design was used in a 2 × 3 factorial, with 2 environmental conditions (thermoneutral and heat stress) and 3 nano-Se levels (0, 0.2, and 0.5 mg/kg of diet. The findings revealed that heat stress negatively affected the growth and feed utilization of quails; indicated by the poor BWG and FCR. Additionally, oxidative stress was aggravated under heat stress condition; indicated by increased lipids peroxidation and decreased antioxidant enzymes activities. The addition of nano-Se, especially at the level of 0.2 mg/kg of diet, significantly improved the performance of heat stressed quails and restored blood oxidative status. The expression profile of inflammatory and antioxidant markers was modulated by heat stress and/or 0.2 and 0.5 nano-Se in conjunction with environmental temperature in quail groups. In comparison to the control group, the heat stress-exposed quails’ expression profiles of IL-2, IL-4, IL-6, and IL-8 showed a notable up-regulation. Significantly lower levels of the genes for IL-2, IL-4, IL-6, and IL-8 and higher levels of the genes for SOD and GPX as compared to the heat stress group demonstrated the ameliorative impact of 0.2 nano-Se. The expression profiles of IL-2, IL-4, IL-6, and IL-8 are dramatically elevated in quails exposed to 0.5 nano-Se when compared to the control group. SOD and GPX markers, on the other hand, were markedly down-regulated. It was concluded that nano-Se by low level in heat stressed growing quails provides the greatest performance and its supplementation can be considered as a protective management practice in Japanese quail diets to reduce the negative impact of heat stress.