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

Objective: 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.

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

Results: The results indicated that SB significantly reduces abdominal and perirenal adipose tissue mass, as well as in 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 TCA cycle metabolites in lamb liver, including oxaloacetate, citrate, cis-aconitate, and succinate (P < 0.05), while simultaneously activating the liver AMPKα1 signaling pathway. This led to upregulated HSL, platelet glycoprotein 4, and long-chain acyl-CoA synthetase mRNA expression (P < 0.05), thereby enhancing liver fatty acid metabolism.

Conclusion: 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.