Conjugated linoleic acid alters growth performance, tissue lipid deposition, and fatty acid composition of darkbarbel catfish (Pelteobagrus vachelli)

Abstract

Fatty liver syndrome is a prevalent problem of farmed fish. Conjugated linoleic acid (CLA) has received increased attention recently as a fat-reducing fatty acid to control fat deposition in mammals. Therefore, the aim of the present study was to determine whether dietary CLA can reduce tissue lipid content of darkbarbel catfish (Pelteobagrus vachelli) and whether decreased lipid content is partially due to alterations in lipid metabolism enzyme activities and fatty acid profiles. A 76-day feeding trial was conducted to investigate the effect of dietary CLA on the growth, tissue lipid deposition, and fatty acid composition of darkbarbel catfish. Five diets containing 0 % (control), 0.5 % (CLA0.5), 1 % (CLA1), 2 % (CLA2), and 3 % (CLA3) CLA levels were evaluated. Results showed that fish fed with 2-3 % CLA diets showed a significantly lower specific growth rate and feed conversion efficiency than those fed with the control diet. Dietary CLA decreased the lipid contents in the liver and intraperitoneal fat with the CLA levels from 1 to 3 %. Fish fed with 2-3 % CLA diets showed significantly higher lipoprotein lipase and hepatic triacylglycerol lipase activities in liver than those of fish fed with the control, and fish fed with 1-3 % CLA diets had significantly higher pancreatic triacylglycerol lipase activities in liver than those of fish fed with the control. Dietary CLA was incorporated into liver, intraperitoneal fat, and muscle lipids, with higher percentages observed in liver compared with other tissues. Liver CLA deposition was at the expense of monounsaturated fatty acids (MUFA). In contrast, CLA deposition appeared to be primarily at the expense of MUFA and n-3 polyunsaturated fatty acids (PUFA) in the intraperitoneal fat, whereas in muscle it was at the expense of n-3 PUFA. Our results suggested that CLA at a 1 % dose can reduce liver lipid content without eliciting any negative effect on growth rate in darkbarbel catfish. This lipid-lowering effect could be in part due to an increment in the activity of lipid metabolism enzymes and an extensive interconversion of fatty acids. Although CLA deposition in muscle (0.66-3.19 % of total fatty acids) are higher than presented in natural sources of CLA, EPA (C20:5n-3) in fish muscle appears simultaneously expendable, when the fish fed with 2-3 % CLA.

Effects of dietary conjugated linoleic acid on growth performance, tissue adipocytokine levels and lipid metabolism of grass carp

“…It is surprising that liver lipid, intraperitoneal fat and muscle lipid significantly decreased in the fish fed with CLA15 to CLA30 diets. In the same way, the liver lipid or muscle lipid was significantly reduced in yellow perch ( Perca flavescen ) (Twibell et al., ), yellow catfish ( Pelteobagrus fulvidraco ) (Tan et al., ), grass carp ( Ctenopharyngodon idella ) (Dong et al., ) and darkbarbel catfish ( Pelteobagrus vachelli ) (Dong et al., ). However, dietary CLA did not significantly affect liver lipid or muscle lipid of the fish species, including channel catfish ( Ictalurus punctatus ) (Twibell & Wilson, ), gilthead sea bream ( Sparus aurata L.) (Diez et al., ) and European sea bass ( Dicentrarchus labrax ) (Makol et al., , ).…”

“…However, dietary CLA did not significantly affect the growth and the feed utilization in the following species: channel catfish ( Ictalurus punctatus ) (Twibell & Wilson, ), rainbow trout ( Oncorhynchus mykiss ) (Figueiredo‐Silva et al., ; Kennedy, Bickerdike, Berge, Dick et al., ) and European sea bass (Makol et al., , ; Valente et al., ). Thus, these discrepancies suggest that dietary CLA has variable influences on growth performance depending on species, CLA dose, feeding duration and CLA chemical form included in the diets (Dong et al., , ; Makol et al., ).…”

“…FAME was analysed, and the individual FA concentration was calculated as described by Dong et al. ().…”

“…Therefore, CLA‐induced effects on mammal lipid deposition may be of considerable interest in aquaculture. In recent years, numerous studies have been conducted to investigate the effects of CLA on growth performance, lipid deposition in tissues and deposition of the fatty acid in various fish species (Dong et al., , ; Makol, Torrecillas, Caballero, Fernández‐Vaquero, & Izquierdo, ; Makol et al., ; Rosa, Andrade, Bandarra, & Nunes, ). However, considerable discrepancies among results in the literature exist, especially in the lipid‐lowering effects of CLA in fish.…”

“…Therefore, CLA-induced effects on mammal lipid deposition may be of considerable interest in aquaculture. In recent years, numerous studies have been conducted to investigate the effects of CLA on growth performance, lipid deposition in tissues and deposition of the fatty acid in various fish species (Dong et al, 2014(Dong et al, , 2015Makol, Torrecillas, Caballero, Fernández-Vaquero, & Izquierdo, 2012;Makol et al, 2009; Rosa, Andrade, Bandarra, & Nunes, the literature exist, especially in the lipid-lowering effects of CLA in fish. For example, the feed intake and growth rate of hybrid striped bass (Morone sax × M. chrysops) (Twibell, Watkins, Rogers, & Brown, 2000), European sea bass (Dicentrarchus labrax) (Makol et al, 2009), yellow catfish (Pelteobagrus fulvidraco) (Tan et al, 2010) and grass carp (Ctenopharyngodon idella) (Dong et al, 2014) are significantly reduced.…”