An evaluation of increasing linolenic acid level in the diet ofMacrobrachium nipponense: Lipid deposition, fatty acid composition and expression of lipid metabolism-related genes

Abstract

To determine the effects of linolenic acid (LNA, in oriental river prawn (Macrobrachium nipponense), an 8-week feeding experiment was conducted using six isonitrogenous and isoenergetic semi-purified diets containing 0.07 g/kg (control), 7.3 g/kg, 16.6 g/kg, 20.2 g/kg, 27.3 g/kg and 36.3 g/kg LNA. The hepatopancreas lipid content decreased significantly when dietary LNA content was >20.2 g/kg. Fatty acid analysis revealed that the percentage of 18:3n-3 in the hepatopancreas significantly increased with increasing dietary LNA levels, while 20:5n-3, 22:5n-3 and 22:6n-3 levels in the hepatopancreas decreased in a curvilinear manner as dietary LNA increased. Additionally, qRT-PCR results revealed that hepatopancreas mRNA expression of acetyl-CoA carboxylase (ACC) decreased with increasing dietary LNA, while the greatest carnitine palmitoyl transferase-1(CPT1) mRNA expression was observed in the 2.73 g/kg and 36.3 g/kg groups. Furthermore, hepatopancreas mRNA expression of acyl-CoA delta-9 desaturase (SCD) and fatty acyl elongase 6(elovl6) was downregulated when prawns fed the diets containing >20.2 g/kg LNA. These results indicate that dietary 18:3n-3 could decrease lipid deposition through increased fatty acid β-oxidation and modulated fatty acid synthesis, and alter fatty acid composition by regulating fatty acyl elongase and fatty acyl desaturase mRNA expression in the M. nipponense. K E Y W O R D S fatty acid composition, linolenic acid, lipid deposition, Macrobrachium nipponense, mRNA expression

Desaturases and elongases involved in polyunsaturated fatty acid biosynthesis in aquatic invertebrates: a comprehensive review

“…In the same study, the authors implied that Elovl6 might have a role in PUFA elongation on the basis that this gene was upregulated in individuals fed ALA-rich diets (Luo et al 2018). Interestingly, an increased expression in response to dietary ALA was also observed for a M. nipponense desaturase termed as "∆6 fatty acyl desaturase" (Luo et al 2018). This gene appears to be a paralogue of those mentioned above from other crustaceans, namely E. sinensis (Yang et al 2013), S. paramamosain (Lin et al 2017), L. vannamei (Chen et al 2017) and C. quadricarinatu (Wu et al 2018).…”

“…Such phylogenetic complexity often leads to misleading nomenclature of desaturases and elongases. For instance, a recent study investigating the responses of Macrobrachium nipponensefed diets with increasing levels of ALA (Luo et al 2018) considered a sphingolipid ∆4 desaturases as a front-end ∆4 desaturases. In the same study, the authors implied that Elovl6 might have a role in PUFA elongation on the basis that this gene was upregulated in individuals fed ALA-rich diets (Luo et al 2018).…”

“…For instance, a recent study investigating the responses of Macrobrachium nipponensefed diets with increasing levels of ALA (Luo et al 2018) considered a sphingolipid ∆4 desaturases as a front-end ∆4 desaturases. In the same study, the authors implied that Elovl6 might have a role in PUFA elongation on the basis that this gene was upregulated in individuals fed ALA-rich diets (Luo et al 2018). Interestingly, an increased expression in response to dietary ALA was also observed for a M. nipponense desaturase termed as "∆6 fatty acyl desaturase" (Luo et al 2018).…”

Effects of dietary lipid levels on the growth, fatty acid profile and fecundity in the oriental river prawn,Macrobrachium nipponense

“…To raise the phospholipid levels in the diet could result in enhanced lipid deposition and increased energy availability for growth and ovarian development (Wu et al, ). Highly unsaturated fatty acids (HUFAs) are known to play important roles in controlling and regulating cell membrane fluidity, signalling pathways, fatty acid β‐oxidation, growth performance, lipid metabolism, pigmentation and egg quality of broodstock in shrimp (Ding et al, , ; Jin et al, ; Luo et al, ; Wu et al, ). In some cases, increasing digestible lipid supplementation in feed has shown a protein‐sparing effect, protein utilization efficiency improvement, as well as nitrogen losses reduction to the environment (González‐Félix, Gatlin, Lawrence, & Perez‐Velazquez, ).…”

�LEO DE BURITI (Mauritia flexuosa) NA ALIMENTA��O DO CAMAR�O Macrobrachium amazonicum (HELLER, 1862)

“…Bhavan et al (2013) avaliaram o desempenho de M. rosenbergii alimentados com rações suplementadas com óleo de girassol e fígado de bacalhau e conseguiram biomassa de 21,25 g, utilizando ração suplementada com óleo de girassol (é um óleo vegetal, assim como o óleo de buriti). Luo et al (2018) conseguiram biomassa de 1,91 g com ração suplementada de óleo de linhaça com níveis crescentes (0, 5, 10, 15, 20 e 25 g) no cultivo do M. nipponense, valores semelhantes aos encontrados no presente trabalho, que atingiu BF 1,45 g, com desvio padrão de ±0,09, no tratamento com 20% de adição do óleo de buriti; sendo assim, como outros óleos vegetais, o buriti complementa a dieta desses camarões para o melhor desenvolvimento de sua BF.…”