Astaxanthin-enriched Oedocladium sp. improves liver health by enhancing fatty acid oxidation and suppressing inflammation in Trachinotus ovatus that was fed a high-fat diet

A high-fat diet can lead to fat deposition in the liver. Astaxanthin is reported to exert a hep-atoprotective effect by affecting host fat metabolism. However, the molecular mechanism used by astaxanthin to regulate fat metabolism is still unclear. This study aimed to examine the function and molecular mechanism used by astaxanthin-enriched Oedocladium sp. in attenuating liver damage and fat deposition that was caused by a high-fat diet. The normal-fat diet (NF), high-fat diet (HF), and high-fat diet supplemented with Oedocladium sp. (HFO) were used to feed juvenile Trachinotus ovatus for 8 weeks. The findings of this study indicated that the HFO diet mitigated growth decline caused by the HF diet by improving digestibility and feed utilization. Meanwhile, the HFO diet reduced serum cholesterol and triglycerides as well as hepatic fat accumulation, alleviating inflammation, oxidative stress, and immunosuppression caused by an HF diet. Addi-tionally, the HFO diet activated AMPK/ACC/CPT1 signal and suppressed the AMPK/SREBP1/FAS signal to promote the catabolism and transport of fat molecules and inhibit fat synthesis. This was regarded as an important regulatory mechanism that was used by Oedocladium sp. to alleviate the fat deposition induced by an HF diet. AMPK may be a key target for Oedocladium sp. to regulate fat metabolism. Therefore, Oedocladium sp., a promising source of astaxanthin, can be used in HF diets to enhance the health and productivity of farmed fish.

Automated summary

This study investigated the function and molecular mechanism of astaxanthin-enriched Oedocladium sp. in attenuating liver damage and fat deposition caused by a high-fat diet. The findings showed that supplementation with Oedocladium sp. improved digestibility, reduced serum cholesterol and triglycerides, and alleviated inflammation and oxidative stress in fish fed a high-fat diet. The study also revealed that Oedocladium sp. activated the AMPK/ACC/CPT1 signal and suppressed the AMPK/SREBP1/FAS signal, promoting fat catabolism and transport while inhibiting fat synthesis. These results suggest that Oedocladium sp. can be a promising source of astaxanthin to enhance the health and productivity of farmed fish.