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

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) ( = 0.003) and aspartatetransaminase (AST) ( = 0.002) activities increased, whereas total PUFA content ( < 0.001) decreased in the liver of lambs fed a HE diet. With the addition of spirulina, serum ALT ( = 0.037) and AST ( = 0.014) activities decreased, whereas EPA ( = 0.004), GLA ( = 0.019), n-6 PUFA ( = 0.005), and total PUFA contents ( = 0.019) increased. Moreover, the crude protein content in the (LTL) increased ( = 0.013), the expression of and was up-regulated, while was down-regulated in liver and LTL ( < 0.05). Spirulina supplementation increased mRNA expression levels of autophagy-associated genes, including that of , and ( < 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.