Cetobacterium somerae-derived acetate production alleviates oxidized fish oil diet-induced hepatopancreatic ferroptosis through the AMPK/SIRT1/PGC-1α signaling pathway in Macrobrachium rosenbergii

Fish oil is an essential lipid source in aquafeed due to its high polyunsaturated fatty acid content. However, its susceptibility to oxidation can harm aquatic animal health and growth. This study investigated the effects of oxidized fish oil (OFO) diet on hepatopancreas health of Macrobrachium rosenbergii , and the mechanism by which Cetobacterium somerae protects against oxidative damage induced by OFO diet. A total of 240 juvenile prawns (3.36 ± 0.02 g) were randomly allocated to three dietary treatments with four replicates of 20 prawns each for 8 weeks: Control (control diet with fresh fish oil diet), OFO (OFO diet), and OFO + Cet (OFO diet supplemented with C. somerae at 1.52 × 10 7 CFU/g). Compared with the OFO group, C. somerae intervention significantly reduced the levels of lipid peroxidation-related markers, including malondialdehyde (MDA), 5-hydroperoxyeicosatetraenoic acid (5-HETE), leukotriene B4 (LTB4), prostaglandins (PGs), and thromboxanes (TXs), while increasing hepatopancreatic antioxidant indicators, including total antioxidant capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and glutathione peroxidase (GSH-Px) ( P < 0.05). Moreover, it also reversed the OFO diet-induced alterations in the relative mRNA expression levels of ferroptosis-related genes ( acsl4 , tfr1 , gpx4 , and slc7a11 ) ( P < 0.05), potentially via the adenosine monophosphate (AMP)-activated protein kinase (AMPK)-sirtuin1 (SIRT1)-peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) signaling pathway. Serum acetic acid, a C. somerae metabolite, exhibited the most pronounced alteration in the C. somerae -treated group ( P = 0.004). Furthermore, 160 juvenile prawns (2.62 ± 0.12 g) were randomly divided into two groups with four replicates of 20 prawns in each for 4 weeks: OFO diet, OFO + 0.15% sodium acetate (0.15% NaAc). Supplementation with 0.15% NaAc in the OFO diet also effectively decreased the peroxides (MDA, 5-HETE, LTB4, and TXs) and reversed the OFO diet-induced alterations in the relative mRNA expression levels of ferroptosis-related genes ( acsl4 , tfr1 , gpx4 , and slc7a11 ) compared with OFO group ( P < 0.05), suggesting a contributory role of acetate in the functionality of C. somerae . Meanwhile, the elevated AMP/adenosine triphosphate (ATP) ratio and upregulated relative mRNA expression levels of acss1/2 , ampk, sirt1 , and pgc-1α ( P < 0.05) indicated that C. somerae- derived acetate activates AMP production, thereby activating the AMPK-SIRT1-PGC-1α signaling pathway . Overall, C. somerae protects against OFO diet-induced hepatopancreatic injury by mitigating ferroptosis via acetate-mediated activation of the AMPK-SIRT1-PGC-1α signaling pathway.