Effect of Lemna minor supplemented diets on growth, digestive physiology and expression of fatty acids biosynthesis genes of Cyprinus carpio.

The potential nutritional value of duckweed Lemna minor (Lemnaceae) was evaluated for common carp Cyprinus carpio fry. Fish were fed diets containing five graded levels of duckweed: 0% (LM0, control), 5% (LM5), 10% (LM10), 15% (LM15) and 20% (LM20). The final weight and specific growth rate were significantly higher in LM15 and LM20 diets fed fish compared to others.

A Piece of the Puzzle-Possible Mechanisms for Why Low Dietary EPA and DHA Cause Hepatic Lipid Accumulation in Atlantic Salmon ().

The present study aimed at elucidating the effects of graded levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the hepatic metabolic health of Atlantic salmon reared in sea cages. Diets containing 10, 13, 16 and 35 g/kg EPA + DHA (designated diets 1.0, 1.

Dietary Lipid:Protein Ratio and n-3 Long-Chain Polyunsaturated Fatty Acids Alters the Gut Microbiome of Atlantic Salmon Under Hypoxic and Normoxic Conditions.

Researchers have adjusted dietary lipid:protein ratios and n-3 long-chain polyunsaturated fatty acids (LC-PUFA) to optimize the growth performance of Atlantic salmon. However, dietary impacts on the gut microbiome are lacking, especially under varying environmental conditions. To examine this response, post-smolt salmon (184 ± 5 g) were fed diets with lipid:protein ratios considered low (180, 570 g/kg) and high (230, 460 g/kg) along with low and high levels of n-3 LC-PUFA (7 or 14 g/kg) while fish were reared under low and high levels of dissolved oxygen (6.

Limitations to Starch Utilization in Barramundi () as Revealed by NMR-Based Metabolomics.

Practical diets for commercial barramundi production rarely contain greater than 10% starch, used mainly as a binding agent during extrusion. Alternative ingredients such as digestible starch have shown some capacity to spare dietary protein catabolism to generate glucose. In the present study, a carnivorous fish species, the Asian seabass () was subjected to two diets with the same digestible energy: Protein (P) - with high protein content (no digestible starch); and Starch (S) - with high digestible (pregelatinized) starch content.

Adequate supply of dietary taurine stimulates expression of molecular markers of growth and protein turnover in juvenile barramundi (Lates calcarifer).

A trial was conducted to investigate the effect of dietary taurine (Tau) supply on the plasma amino acid composition and hepatic expression of several genes in juvenile barramundi (Lates calcarifer) after feeding. Triplicate tanks of fish (average weight, 89.3 g) were fed diets containing either a deficient (1 g kg), adequate (8 g kg) or excessive (19 g kg) level of dietary Tau.

Endogenous production of -3 long-chain PUFA from first feeding and the influence of dietary linoleic acid and the -linolenic:linoleic ratio in Atlantic salmon ().

Atlantic salmon (Salmo salar) possess enzymes required for the endogenous biosynthesis of n-3 long-chain PUFA (LC-PUFA), EPA and DHA, from α-linolenic acid (ALA). Linoleic acid (LA) competes with ALA for LC-PUFA biosynthesis enzymes leading to the production of n-6 LC-PUFA, including arachidonic acid (ARA). We aimed to quantify the endogenous production of EPA and DHA from ALA in salmon fed from first feeding on diets that contain no EPA and DHA and to determine the influence of dietary LA and ALA:LA ratio on LC-PUFA production.

Endogenous biosynthesis of n-3 long-chain PUFA in Atlantic salmon.

A more efficient utilisation of marine-derived sources of dietary n-3 long-chain PUFA (n-3 LC PUFA) in cultured Atlantic salmon (Salmo salar L.) could be achieved by nutritional strategies that maximise endogenous n-3 LC PUFA synthesis. The objective of the present study was to quantify the extent of n-3 LC PUFA biosynthesis and the resultant effect on fillet nutritional quality in large fish.

Impact of dietary starch on extrahepatic tissue lipid metabolism in farmed European (Dicentrarchus labrax) and Asian seabass (Lates calcarifer).

In aquaculture, there is high interest in substituting marine-derived with vegetable-based ingredients as energy source. Farmed carnivorous fish under high carbohydrate diets tend to increase adiposity but it remains unclear if this happens by increased lipid retention/accumulation, promotion of lipogenic pathways, or both. In order to determine the response of extrahepatic tissue to dietary starch, European (Dicentrarchus labrax) and Asian (Lates calcarifer) seabass were fed a control (low starch; LS) or experimental (high starch; HS) diet, for at least 21 days and then transferred for 6 days to saltwater enriched with deuterated water HO.

Coping with climatic extremes: Dietary fat content decreased the thermal resilience of barramundi (Lates calcarifer).

Aquatic organisms, including important cultured species, are forced to contend with acute changes in water temperature as the frequency and intensity of extreme weather events worsen. Acute temperature spikes are likely to threaten aquaculture species, but dietary intervention may play an important protective role. Increasing the concentration of macronutrients, for example dietary fat content, may improve the thermal resilience of aquaculture species, however, this remains unexplored.

In vitro characteristics of an Atlantic salmon (Salmo salar L.) hind gut microbial community in relation to different dietary treatments.

In this study, microbial community dynamics were assessed within a simple in vitro model system in order to understand those changes influenced by diet. The abundance and diversity of bacteria were monitored within different treatment slurries inoculated with salmon faecal samples in order to mimic the effects of dietary variables. A total of five complete diets and two ingredients (plant meal) were tested.

An analysis of partial efficiencies of energy utilisation of different macronutrients by barramundi (Lates calcarifer) shows that starch restricts protein utilisation in carnivorous fish.

This study examined the effect of including different dietary proportions of starch, protein and lipid, in diets balanced for digestible energy, on the utilisation efficiencies of dietary energy by barramundi (Lates calcarifer). Each diet was fed at one of three ration levels (satiety, 80 % of initial satiety and 60 % of initial satiety) for a 42-d period. Fish performance measures (weight gain, feed intake and feed conversion ratio) were all affected by dietary energy source.

Defining the allometric relationship between size and individual fatty acid turnover in barramundi Lates calcarifer.

An experiment was conducted with barramundi (Asian seabass; Lates calcarifer) to examine the allometric scaling effect of individual fatty acids. Six treatment size classes of fish were deprived of food for 21days (Treatment A, 10.5±0.

Eicosapentaenoic Acid, Arachidonic Acid and Eicosanoid Metabolism in Juvenile Barramundi Lates calcarifer.

A two part experiment was conducted to assess the response of barramundi (Lates calcarifer; initial weight = 10.3 ± 0.03 g; mean ± S.

Atlantic Salmon (Salmo salar L.) Gastrointestinal Microbial Community Dynamics in Relation to Digesta Properties and Diet.

To better understand salmon GI tract microbial community dynamics in relation to diet, a feeding trial was performed utilising diets with different proportions of fish meal, protein, lipid and energy levels. Salmon gut dysfunction has been associated with the occurrence of casts, or an empty hind gut. A categorical scoring system describing expressed digesta consistency was evaluated in relation to GI tract community structure.

Rapid effects of essential fatty acid deficiency on growth and development parameters and transcription of key fatty acid metabolism genes in juvenile barramundi (Lates calcarifer).

Barramundi (Lates calcarifer), a catadromous teleost of significant and growing commercial importance, are reported to have limited fatty acid bioconversion capability and therefore require preformed long-chain PUFA (LC-PUFA) as dietary essential fatty acid (EFA). In this study, the response of juvenile barramundi (47·0 g/fish initial weight) fed isolipidic and isoenergetic diets with 8·2% added oil was tested. The experimental test diets were either devoid of fish oil (FO), and thus with no n-3 LC-PUFA (FO FREE diet), or with a low inclusion of FO (FO LOW diet).

A comparative analysis of the response of the hepatic transcriptome to dietary docosahexaenoic acid in Atlantic salmon (Salmo salar) post-smolts.

Background: The present study aimed to explore the impact of dietary docosahexaenoic acid (DHA) on aspects of the metabolism of Atlantic salmon (Salmo salar). The effects of diets containing increasing levels of DHA (1 g kg(-1), 3 g kg(-1), 6 g kg(-1), 10 g kg(-1) and 13 g kg(-1)) on the liver transcriptome of post-smolt salmon was examined to elucidate patterns of gene expression and responses of specific metabolic pathways. Total RNA was isolated from the liver of individual fish and analyzed using a custom gene expression 44K feature Atlantic salmon oligo-microarray.

Identification of genes involved in reproduction and lipid pathway metabolism in wild and domesticated shrimps.

The aims of this study were to identify genes involved in reproduction and lipid pathway metabolism in Penaeus monodon and correlate their expression with reproductive performance. Samples of the hepatopancreas and ovaries were obtained from a previous study of the reproductive performance of wild and domesticated P. monodon broodstock.

Influence of dietary docosahexaenoic acid in combination with other long-chain polyunsaturated fatty acids on expression of biosynthesis genes and phospholipid fatty acid compositions in tissues of post-smolt Atlantic salmon (Salmo salar).

To investigate interactions of dietary LC-PUFA, a dose-response study with a range of docosahexaenoic acid (DHA; 22:6n-3) levels (1 g kg(-1), 5 g kg(-1), 10 g kg(-1), 15 g kg(-1) and 20 g kg(-1)) was performed with post-smolts (111 ± 2.6g; mean ± S.D.

Readily available sources of long-chain omega-3 oils: is farmed Australian seafood a better source of the good oil than wild-caught seafood?

Seafood consumption enhances intake of omega-3 long-chain (≥C₂₀) polyunsaturated fatty acids (termed LC omega-3 oils). Humans biosynthesize only small amounts of LC-omega-3, so they are considered semi-essential nutrients in our diet. Concern has been raised that farmed fish now contain lower LC omega-3 content than wild-harvested seafood due to the use of oil blending in diets fed to farmed fish.

Interactions between dietary docosahexaenoic acid and other long-chain polyunsaturated fatty acids on performance and fatty acid retention in post-smolt Atlantic salmon (Salmo salar).

A study with varying dietary inclusion levels (1, 5, 10, 15 and 20 g kg(-1)) of docosahexaenoic acid (DHA; 22:6n-3) was conducted with post-smolt (111 ± 2.6 g; mean ± S.) Atlantic salmon (Salmo salar) over a 9-week period.

Postprandial molecular responses in the liver of the barramundi, Lates calcarifer.

The regulation of gene expression by nutrients is an important mechanism governing energy storage and growth in most animals, including fish. At present, very few genes that regulate intermediary metabolism have been identified in barramundi, nor is there any understanding of their nutritional regulation. In this study, a partial barramundi liver transcriptome was assembled from next-generation sequencing data and published barramundi EST sequences.

Mechanisms of colour adaptation in the prawn Penaeus monodon.

Exposure of prawns to dark- or light-coloured substrates is known to trigger a strong colour adaptation response through expansion or contraction of the colouration structures in the prawn hypodermis. Despite the difference in colour triggered by this adaptive response, total levels of the predominant carotenoid pigment, astaxanthin, are not modified, suggesting that another mechanism is regulating this phenomenon. Astaxanthin binds to a specific protein called crustacyanin (CRCN), and it is the interaction between the quantities of each of these compounds that produces the diverse range of colours seen in crustacean shells.

Growing backwards: an inverted role for the shrimp ortholog of vertebrate myostatin and GDF11.

Myostatin (MSTN) and growth differentiation factor-11 (GDF11) are closely related proteins involved in muscle cell growth and differentiation as well as neurogenesis of vertebrates. Both MSTN and GDF11 negatively regulate their functions. Invertebrates possess a single ortholog of the MSTN/GDF11 family.