Effects of dietary lipid level on growth, fatty acid composition, digestive enzymes and expression of some lipid metabolism related genes of orange-spotted grouper larvae (Epinephelus coioidesH.)

Abstract

A 4‐week study was conducted to investigate the effects of dietary lipid level on growth, fatty acid composition, activities of digestive enzymes and some lipid metabolism related genes of orange‐spotted grouper larvae (Epinephelous coioides). Six isonitrogenous (57% crude protein) diets were formulated to contain graded contents of lipid (5.94%, 9.92%, 13.30%, 17.71% and 21.87% dry weight, respectively) using fish oil as main lipid source. Each diet was fed six times daily to triplicate groups of fish (71 ± 2 mg, 29 DAH). Results showed that the highest SGR and survival of larvae occurred in 17.71% and 13.30% lipid group respectively. The optimal dietary lipid requirement of larval grouper was estimated to be 15.99% based on SGR. Activities of pepsin and lipase were significantly higher in 17.71% lipid group compared to the rest ones. However, the highest activities of trypsin and amylase occurred in 9.92% and 5.94% lipid treatment respectively. The expression of fatty acid synthesis (FAS) decreased significantly with increasing dietary lipid, while the expression of lipoprotein lipase (LPL) and hormone sensitive lipase (HSL) significantly increased first and then decreased significantly. Compared to other treatment, larvae fed diets with 13.30% and 17.71% lipid have a significant higher relative expression of LPL and HSL respectively. Results of this study suggested that larvae fed the diet with appropriate lipid content showed higher growth performance. Moreover, dietary lipid content could also influence both de novo lipogenesis and lipolysis in transcriptional level.

Activities of digestive enzymes and histology of digestive system during larval development of devil stinger (Inimicus japonicus)

“…The supernatant was collected for further assay. The activity of pepsin was measured according to Folin determination method (Lowry, Rosebrough, Fair & Randall, ) with some modifications (Li et al., ). Bovine haemoglobin (Sigma H‐2625) was used as substrate.…”

“…Samples were homogenized in twofold volume ice-cold ultrapure water and then were centrifuged for 15 min at 8,000 g. The supernatant was collected for further assay. The activity of pepsin was measured according to Folin determination method (Lowry, Rosebrough, Fair & Randall, 1951) with some modifications (Li et al, 2016). Bovine haemoglobin (Sigma H-2625) was used as substrate.…”

Effects of dietary protein and lipid levels on growth performance, feed utilization and body composition of juvenile hybrid grouper, Epinephelus fuscoguttatus×E. lanceolatus

“…Similarly, Lee and Kim (2001) reported the increased wholebody linoleic acid in masu salmon (Oncorhynchus masou Brevoort) as dietary lipid increased. However, results of some other studies showed the significant decrease of muscle and/or liver linoleic acid content by increasing dietary lipid in white seabass (Atractoscion nobilis) (López et al, 2009), Japanese seabass (Lateolabrax japonicus L.) (Luo et al, 2010) and orange spotted grouper (Li et al, 2015). It should be pointed out that in this study a mixture of soybean oil and linseed oil were used in high lipid diets which are considered as rich sources of linoleic and linolenic acids and this may be responsible for the increased muscle and liver linoleic acid contents.…”

The influence of dietary fish oil replacement with mixture of vegetable oils on reproductive performance, immune responses and dynamic of fatty acids during embryogenesis in Oncorhynchus mykiss

“…Either dietary lipid level or FA profile could influence both lipogenesis, lipolysis as well as lipid absorption and transport at genes transcriptional and translational levels (FA synthesis, acetyl‐CoA carboxylase‐ß, lipoprotein lipase and hormone sensitive lipase), which can affect dynamic of FA profile during embryogenesis and subsequently larval quality (Bonacic et al, ; Li et al, ; Yuan et al, ). Our findings exhibited embryo's FA composition either affected by experimental feeds FA profile or embryonic developmental stages (Tables ).…”