The effects of Myo-inositol on antioxidant capacity and immunity in freshwater crayfish

Abstract

Myo-inositol (MI ) plays a vital role in the growth and development of crustaceans. Although most researchers have focused on the critical role of MI in fish, its application in crustaceans is lacking. A 6-week trial was conducted to comparatively evaluate the effects of 6 levels of dietary MI (0, 500, 1000, 2000, 3000, and 4000 mg/kg diet) in juvenile freshwater crayfish Procambarus clarkii (6.39 ± 0.05) g. This study aimed to investigate the effects of dietary MI on antioxidant capacity, non-specific immunity, and possible molecular mechanisms in freshwater crayfish. Research shows dietary MI could improve hepatopancreatic antioxidant enzyme activity and non-specific immunity (P < 0.05). MI can be converted into phosphatidylinositol 3-kinase (PI3K) under the action of phospholipase, which activates the PI3K/AKT signaling pathway. The PI3K/AKT signaling pathway can promote the transcription level of Nrf2-Keap1, thereby promoting the expression of antioxidant-related genes (sod, cat, and gpx) to improve the antioxidant mechanism (P < 0.05). In addition, dietary MI could prevent the occurrence of endoplasmic reticulum stress (ERS, bip, xbp1, and ire1) and inhibit the expression of inflammatory factors (jnk, il-6, tnf-α, and nf-κb) and apoptosis-related genes (bax, cytc, and casp3) (P < 0.05). Dietary MI improves antioxidant capacity by regulating increased Nrf2 translocation and NF-κB translocation. In conclusion, dietary MI can enhance the antioxidant defense system of freshwater crayfish by activating the PI3K/AKT pathway and coordinating the transcription levels of Nrf2 and NF-κB.