Changes in activities and mRNA expression of lipoprotein lipase and fatty acid synthetase in large yellow croaker,Larimichthys crocea(Richardson), during fasting

Abstract

Over‐winter fasting and man‐made food deprivation to increase meat quality are common in the process of large yellow croaker (Larimichthys crocea) aquaculture. This study aimed to determine the changes in lipoprotein lipase (LPL) and fatty acid synthetase (FAS) activities and mRNA expressions, and the relationships between these changes and fat content in large yellow croaker liver and muscle tissues during fasting. A total of 2933 bp LPL cDNA, including an open reading frame of 1533 bp encoding 510 amino acids, and a 1233 bp fragment of FAS cDNA coding 411 amino acids were cloned. Expressions of both genes were ubiquitous. During a 35‐day fasting period, the hepatosomatic index and fat content in muscle and liver were significantly decreased (P < 0.05). mRNA levels of LPL increased significantly during the fasting period except the first 3 days, and FAS mRNA levels decreased significantly in both muscle and liver (P < 0.05) although there were some fluctuations. Muscle and liver LPL activities were significantly higher following fasting for 7 days, decreased to the initial value following fasting for 14 days, and elevating significantly afterwards (P < 0.05). FAS activities in muscle and liver maintained a significantly decreasing trend during the short‐term fasting (P < 0.05) and kept obviously rising thereafter (P < 0.05). Activities and mRNA levels of both LPL and FAS were not always consistent, which implied that both pre‐translational and post‐translational regulations existed during fasting. Our results suggest that the reasonable fasting time is 21 days before harvesting when fat content decreased significantly.

Effects of dietary lipid levels on growth performance, plasma biochemistry, lipid metabolism and intestinal microbiota of juvenile golden pompano ( Trachinotus ovatus )

“…In this study, the significantly higher NEFA content of fish in D4 and D5 group indicated a higher risk of disease than that in other groups. FAS was closely related to the synthesis of long-chain fatty acids (Huang et al, 2017). A study on hybrid Clarias catfish (Clariasmarcrocephal ×C.gariepinus) found that FAS activities emerged a negative correlation with dietary lipid level (Jantrarotai et al, 1994), which supported our study.…”

Effect of starvation on intestinal morphology, digestive enzyme activity and expression of lipid metabolism‐related genes in javelin goby ( Synechogobius hasta )

“…Similarly, the increased expression/activity of fas was reported in 5‐day starved spotted seabass ( Lateolabrax maculates ) (Huang et al, 2018). The differences in fas abundance described before may suggest that the transcriptional response of the fas gene to starvation in fish is species‐specific (Huang et al, 2017) and tissue‐specific. Given the role of scd1 in the biosynthesis of monounsaturated fatty acids (MUFAs) by converting palmitic acid and stearic acid into palmitoleic and oleic (Castro et al, 2011; Tocher, 2003; Xu et al, 2015), its lower expression induced by 14‐day food deprivation may suggest that the long‐chain fatty acid biosynthesis was significantly suppressed in S .…”

“…The inconsistent alterations in fas expression under starvation also appeared in other fish species. In large yellow croaker ( Larimichthys crocea ), fas mRNA expression and Fas activity in the muscle gradually decreased until 5 days after starvation and then significantly increased afterwards (Huang et al, 2017), whereas its expression trend remained stable in the liver (Huang et al, 2017). Similarly, the increased expression/activity of fas was reported in 5‐day starved spotted seabass ( Lateolabrax maculates ) (Huang et al, 2018).…”

Short-term starvation in silver pomfret (Pampus argenteus): molecular effects on lipid mobilization and utilization

“…In fish, the LPL expression at the mRNA level and its activity are regulated by starvation in the liver of tilapia (Tian et al . ) and large yellow croaker (Huang, Xue, Shi & Zhao ), but data on the effects of starvation on expressions of CD36 and FATP1 are scarce. Only two studies have examined the effects of starvation on expressions of CD36 and FATP1 at the mRNA level in Atlantic salmon (Sánchez‐Gurmaches, Østbye, Navarro, Torgersen, Hevrøy, Ruyter & Torstensen ) and rainbow trout (Sánchez‐Gurmaches, Cruz‐Garcia, Gutiérrez & Navarro ).…”

“…; Huang et al . ), while the expressions of PPARα and CPT1a are increased in starved tilapia (Ning, He, Li, Lu, Jiao, Li, Li, Zhang, Chen & Du ). Few studies have been conducted to explore the effects of starvation on lipid metabolic pathways.…”