# Effects of dietary sodium butyrate supplementation on fat metabolism in lamb adipose and liver tissues

## TL;DR

This study shows that adding sodium butyrate to lamb diets reduces fat accumulation and improves fat metabolism in adipose and liver tissues.

## Contribution

The study reveals novel mechanisms by which sodium butyrate activates AMPK signaling and modulates lipid metabolism in lambs.

## Key findings

- Sodium butyrate reduces abdominal and perirenal adipose tissue mass and adipocyte size in lambs.
- Sodium butyrate activates AMPKα1 in adipose tissue, upregulating HSL and downregulating fatty acid synthesis genes.
- Sodium butyrate increases tricarboxylic acid cycle metabolites and enhances liver fatty acid metabolism.

## Abstract

Sodium butyrate (SB) is a potentially useful feed additive; however, its effects on lipid metabolism in adipose and liver tissues of lambs are still not fully explored. This study systematically examined the effects and underlying mechanisms of dietary SB supplementation on lipid metabolism in lamb adipose and liver tissues from an adipose-blood-liver perspective.

Twelve 3-month-old male lambs (22.37±2.05 kg) were randomly divided into a control group and an SB group. We measured the adipose tissue cellular morphology and lipid metabolism-related indices in both adipose and liver tissues.

The results indicated that SB significantly reduces abdominal and perirenal adipose tissue mass, as well as the average area and diameter of adipocytes (p<0.05). Dietary supplementation with SB activated adenosine 5′-monophosphate-activated protein kinase α1 (AMPKα1) in lamb adipose tissue, resulting in upregulated mRNA expression of hormone-sensitive triglyceride lipase (HSL) and downregulated mRNA expression of sterol regulatory element-binding protein 1 and fatty acid synthase (p<0.05). Simultaneously, adiponectin secretion and receptor expression in adipose tissue, as well as serum adiponectin levels, were significantly elevated (p<0.05). Moreover, dietary supplementation with SB increased the levels of tricarboxylic acid cycle metabolites in lamb liver, including oxaloacetate, citrate, cis-aconitate, and succinate (p<0.05), while simultaneously activating the liver AMPKα1 signaling pathway. These changes led to upregulated HSL, platelet glycoprotein 4, and long-chain acyl-CoA synthetase mRNA expression (p<0.05), thereby enhancing liver fatty acid metabolism.

In summary, dietary supplementation with SB alters adiponectin levels in lambs, activates the AMPK signaling pathway, promotes adipose tissue lipolysis, and regulates liver lipid metabolism. The findings provide valuable insights into the use of SB for managing lamb body fat reserves and offer a robust basis for further research in animal bioscience.