Spirulina supplementation improves lipid metabolism and autophagic activities in the liver and muscle of Hu lambs fed a high-energy diet

Arch Anim Nutr. 2020 Dec;74(6):476-495. doi: 10.1080/1745039X.2020.1820806. Epub 2020 Oct 16.

Abstract

The current study aimed to examine the effects of dietary spirulina supplementation in high-energy (HE) diets on fatty acid metabolism in sheep, and preliminarily explored the potential mechanisms underlying the associated autophagy-mediated regulation of lipid metabolism. In a 2 × 3 factorial design, including six treatment combinations of two metabolisable energy diets (10 and 11 MJ/kg DM), three spirulina supplementation levels (0, 1%, and 3%) were used. Serum alanineaminotransferase (ALT) (p = 0.003) and aspartatetransaminase (AST) (p = 0.002) activities increased, whereas total PUFA content (p < 0.001) decreased in the liver of lambs fed a HE diet. With the addition of spirulina, serum ALT (p = 0.037) and AST (p = 0.014) activities decreased, whereas EPA (p = 0.004), GLA (p = 0.019), n-6 PUFA (p = 0.005), and total PUFA contents (p = 0.019) increased. Moreover, the crude protein content in the Longissimus thoracis et lumborum (LTL) increased (p = 0.013), the expression of PPARα and PPARγ was up-regulated, while ELOVL2 was down-regulated in liver and LTL (p < 0.05). Spirulina supplementation increased mRNA expression levels of autophagy-associated genes, including that of Beclin-1, AMPK, and ULK1 (p < 0.05). In conclusion, spirulina supplementation in a HE diet exerted a protective effect on the liver, increased PUFA content, and modulated expression levels of autophagy-related genes in growing lambs.

Keywords: Autophagy; Spirulina; high-energy diet; polyunsaturated fatty acids; sheep.

MeSH terms

  • Animal Feed / analysis
  • Animals
  • Autophagy / drug effects*
  • Diet / classification
  • Diet / veterinary*
  • Dietary Supplements / analysis
  • Dose-Response Relationship, Drug
  • Lipid Metabolism / drug effects*
  • Liver / drug effects*
  • Liver / physiology
  • Male
  • Muscle, Skeletal / drug effects*
  • Muscle, Skeletal / physiology
  • Random Allocation
  • Sheep, Domestic / physiology*
  • Spirulina / chemistry*