Abstract:

【Objective】 The aim of the current study was to evaluate the effects of dietary supplementation with α-ketoglutarate (AKG) on muscle energy metabolism with reference to its molecular mechanism in weaned pigs after repetitive stimulation with lipopolysaccharide (LPS). 【Method】 Twenty-four piglets were assigned to a 2×2 factorial arrangements with LPS challenge (or without) and dietary supplementation of AKG at 0 and 1% as the main factors, total four treatments. The 24 weaned piglets (Duroc×Landrace×Yorkshire, 6.79±0.32 kg BW) were randomly allocated to one of the 4 treatment groups (6 replicates for each group). LPS challenged piglets were given a single intraperitoneal injection of LPS at 10, 13, 15 d and non-challenged piglets were injected intraperitoneally with physiological saline at the same doses. On 16 d, all pigs were killed and anesthesia and gastrocnemius tissues were excised. Muscle adenine nucleotide was assayed by HPLC, western blot assays were performed for muscle AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) expression and their phosphorylation. 【Result】 There were significantly interaction effects of AKG supplementation and LPS challenge on AMP level and AMP/ATP ratio (P<0.05). Dietary supplementation of 1% AKG increased ADP (P<0.05), attenuated the increase of AMP level and AMP/ATP and the decrease of ADP and energy charge (EC) induced by LPS challenge (P<0.05). AKG supplementation and LPS challenge had no effects on the expression and phosphorylation of AMPK. Dietary supplementation of 1% AKG significantly inhibited ACC phosphorylation. LPS challenge significantly increased the expression and phosphorylation of ACC (P<0.05). 【Conclusion】These results demonstrated that, under the present experimental conditions, LPS challenge resulted in muscle energy depletion. Dietary supplementation of 1% AKG could maintain muscle energy metabolism. Dietary supplementation of 1% AKG might affect muscle energy metabolism via ACC signaling. AKG might affect muscle energy metabolism via ACC signaling, therefore improve body energy status after LPS challenge.

Key words: α-ketoglutarate, lipopolysaccharide, weaned piglets, muscle energy metabolism, AMP-activated protein kinase, acetyl-CoA carboxylase