Characterization and function of PTEN-induced putative kinase 1 (PINK1) in process of Zinc alleviates hepatic lipid deposition of yellow catfish (Pelteobagrus fulvidraco).

PTEN-induced putative kinase 1 (PINK1) is a key regulator of mitophagy, however, the relevant information remains poorly understood on aquatic animals. Here, a PINK1 gene was cloned, characterized and functionally studied in yellow catfish. PINK1 encoded a protein containing 570 amino acids, 2 functional domains. High fat (15.66%) fed fish showed a downregulation trend of liver PINK1 expression than that of normal fat (10.14%) group, and was reversed by the addition of Zn. In the in vitro study, high fat (HF) can increase lipid deposition and decrease by addition Zn (HFZ) in hepatocytes, whereas above phenomena reversed by overexpression/interference of PINK1, respectively. In addition, the addition of Zn can significantly affect mitochondrial activity, increase mitophagy, and improve the antioxidant activity of hepatocytes. Together, these findings illustrated that yellow catfish PINK1 is conserve, and it participated in mitochondria control of fish. These findings indicate Zn could alleviate high fat-induced hepatic lipid deposition of fish by activating PINK1-mediated mitophagy and provide basis for further exploring new approach for decreasing lipid deposition in fish products during aquaculture.

Effects of Dietary Protein Levels on Growth, Digestive Enzyme Activity, Antioxidant Capacity, and Gene Expression Related to Muscle Growth and Protein Synthesis of Juvenile Greasyback Shrimp (Metapenaeus ensis).

An 8-week feeding trial was conducted to assess the effects on growth, antioxidant capacity, digestive enzyme activity, and gene expression related to muscle growth and protein synthesis of juvenile greasyback shrimp (Metapenaeus ensis) using five experimental diets containing 29.37%, 34.30%, 39.11%, 44.05%, and 49.32% of protein. The results demonstrated that juvenile greasyback shrimp consuming 39.11%, 44.05%, and 49.32% dietary protein had a significantly higher final body weight (FBW), weight gain (WG), feed conversion ratio (FCR), and specific growth rate (SGR) than other groups (p < 0.05). The protein efficiency ratio (PER) showed a significantly quadratic pattern with increasing dietary protein levels (p < 0.05). The highest trypsin and pepsin activities were observed in the group with a protein level of 44.05% (p < 0.05). Relatively higher superoxide dismutase (SOD) activity was found in groups with protein levels of 39.11% (p < 0.05). Alkaline phosphatase (AKP) and catalase (CAT) activity showed a significantly linear increasing pattern with increasing protein intake up to 44.05%, and then decreased gradually (p < 0.05). Compared to the dietary 29.37% protein level, the expression levels of myogenic regulatory factors (mef2α, mlc, and myf5) and mTOR pathway (mtor, s6k, akt, and pi3k)-related genes were significantly up-regulated in muscle with 39.11%, 44.05%, and 49.32% dietary protein levels (p < 0.05). The AAR pathway (gcn2, eif2α, and atf4)-related gene expression levels were significantly lower in muscles with 39.11%, 44.05%, and 49.32% protein levels than in other groups (p < 0.05). Based on the broken-line regression analysis of SGR, the estimated appropriate dietary protein requirement for juvenile greasyback shrimp is 38.59%.