Influence of dietary inclusion of a wet processed faba bean protein concentrate on post-smolt Atlantic salmon (Salmo salar)
ABSTRACT: In the present study, a faba bean protein isolate (wBPC) with almost ~80 % crude protein produced by a wet process was investigated in feeds for Atlantic salmon in seawater. Four dietary treatments were tested including one treatment with high inclusion of fishmeal (400 g kg-1, named FM) and three treatments with low fishmeal (216 g kg-1) and increasing inclusions of faba bean protein concentrate (0, 70 and 140 g kg-1) substituting soy protein concentrate (236, 125 and 45 g kg-1), named SPC, BPC7 and BPC14 respectively.
Project description:High-quality sources of protein for the formulation of feeds of carnivorous fish species such as Atlantic salmon are currently being sought. In an earlier screening trial we evaluated for the first time in Atlantic salmon (Salmo salar) the applicability of air-classified faba bean (Vicia faba) protein concentrate (BPC) inclusions in combination with soy protein concentrate (SPC) and fishmeal (FM) using parr as a model. Based on the results in parr in freshwater, the present study tested the hypothesis that BPC can effectively replace SPC as a dietary protein source in post-smolt Atlantic salmon in seawater. Herein we compare three dietary treatments, including BPC0 (no BPC), BPC20 (20% BPC) and BPC40 (40% BPC). Full details on diet formulation are available in the publication.
Project description:The production of carnivorous fish such as Atlantic salmon (Salmo salar) is dependent on the availability of high quality protein required as a sustainable substitute for the formulation of the feeds. Plants have arguably the greatest potential, however a major limitation is associated with the presence of anti-nutritional factors. Investigating novel raw materials involves understanding the physiological consequences of the substitution. The primary aim of the present study was to assess the metabolic response of salmon to increasing inclusion of air-classified faba bean protein concentrate (BPC) in feeds as a replacement for soy (SPC). Specifically, we focused on the hepatic transcriptome response to dietary BPC inclusion over a range including commercially relevant levels (e.g. 11-22%) to levels giving impaired performance (45 %). The present investigation provided a profile of the salmon hepatic response to BPC indicating that fish tolerated moderate substitution of dietary SPC with BPC with no evident negative effects on the hepatic physiology of the fish. The analysis of extreme levels of substitution provided insights into physiological mechanisms that are significantly altered providing the basis for further investigation and improvement.
Project description:Facing a bottleneck in the growth of aquaculture, and a gap in the supply and demand of the highly beneficial omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA), sustainable alternatives to the traditional feeds are much needed. Therefore, in this trial, an oil extracted from newly designed plant, Camelina sativa, was tested for its n-3 replacement capabilities, using three different groups of post-smolt Atlantic salmon (Salmo salar) which were fed for 12 weeks three experimental diets; a control diet containing a blend of fish oil (5 %) and rapeseed oil (15 %) (FO), a wild-type Camelina (20 %) (WCO) and the transgenic Camelina oil (20 %) (DCO), all of them having the same basal composition. By comparing them, an overall evaluation of fish performance, fatty acid profile, feeds digestibility and gene expression was done. In the context of the new transgenic diet, there were no negative effects on the growth, survival rate or health of the fish. The whole fish n-3 levels were highest in the DCO-fed fish with EPA+DHA levels almost double compared to FO-fed fish and more than double when compared to WCO-fed ones, clearly suggesting the efficiency of the Camelina oil in providing competitive levels of n-3 LC-PUFA compared to the commercial “gold standard”.
Project description:The present study aimed to determine the impact of dietary docosahexaenoic acid (DHA) on the metabolism of Atlantic salmon (Salmo salar). The effects of diets containing increasing levels of DHA (1 g kg-1, 5 g kg-1, 10 g kg-1, 15 g kg-1 and 20 g kg-1) on the liver transcriptome of post-smolt salmon was determined using regression analysis to elucidate patterns of gene expression and responses of specific metabolic pathways. Total RNA was isolated from liver of individual fish and analyzed using a custom 44K Atlantic salmon oligo-microarray. The expression of up to 911 unique annotated genes was significantly affected by dietary DHA inclusion relative to a low DHA reference diet. Using regression analysis, 797 unique genes were found with a significant linear correlation between expression level and dietary DHA. Gene-Set Enrichment Analysis (GSEA) identified a range of pathways that were significantly affected by dietary DHA content. Pathways that showed a significant response to dietary DHA level included those for long-chain polyunsaturated fatty acid biosynthesis, fatty acid elongation, steroid biosynthesis, glycan biosynthesis, protein export and protein processing in the endoplasmic reticulum. These findings suggest that in addition to clear roles in influencing lipid metabolic pathways, DHA also has key functional roles in other biosynthetic pathways distinct from lipid metabolism.
Project description:The aim of the present study was to generate an experimental model to characterize the nutrigenomic profile of a plant-derived nutritional stress (S30 = 300 g Kg-1 Soybean Meal). Our results provided: a) a snapshot of molecular signatures describing a chronic and advanced nutritional stress to which future nutrigenomic studies might refer to; and b) a platform for the identification of candidate genes for the molecular phenotyping of several physiological parameters in liver and distal intestine. Atlantic salmon was used as a model. The nutritional stress was induced by inclusions of dietary defatted soybean meal (SBM) up to a level of 300 g kg-1, being this ingredient extensively demonstrated to induce reduced performance and enteropathy in the distal intestine (Baeverfjord and Krogdahl, 1996;Urán et al., 2009;URÁN et al., 2008). A control treatment with no SBM (S0) as well as intermediate levels of inclusion (100 g kg-1 and 200 g kg-1 SBM) were included to span a range of optimal and sub-optimal conditions. Performance parameters were measured and impaired growth was taken as an indicator of pronounced and chronic nutritional stress. Molecular analyses were performed in two tissues, liver and distal intestine. Distal intestine was chosen for being the site most morphologically and physiologically affected during the development of intestinal pathologies associated with plant ingredients such as SBM (Baeverfjord and Krogdahl, 1996;Kortner et al., 2011), while liver for being arguably the most metabolic active tissue. These tissues have been the most investigated targets in nutritional studies on fish so far. To the best of our knowledge, this study is the most comprehensive of its kind to report on the transcriptomic profile of the distal intestine and the liver, hence highlighting the supporting role of this tissue, in fish undergoing SBM-induced nutritional stress. Skugor et al (, 2011) described gene expression profiles of liver and intestine in fish fed 200 g kg-1 SBM inclusion using a 11K trout array. By investigating a larger number of probes (44K) in a more severe nutritional stress (300 g kg-1), our work will add further nutrigenomic information to the current literature.
Project description:Currently, the only sustainable alternatives for dietary fish oil (FO) in aquafeeds are vegetable oils (VO) that are devoid of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA). Entirely new sources of n-3 LC-PUFA such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids through de novo production is a potential solution to fill the gap between supply and demand of these important nutrients. Camelina sativa,was metabolically engineered to produce a seed oil (ECO) with > 20 % EPA and its potential to substitute for FO in Atlantic salmon feeds was tested. Fish were fed one of three experimental diets containing FO, wild-type camelina oil (WCO) or ECO as the sole lipid sources for 7-weeks. Inclusion of ECO did not affect any of the performance parameters studied and enhanced apparent digestibility of individual n-6 and n-3 PUFA compared to dietary WCO. High levels of EPA were maintained in brain, liver and intestine (pyloric caeca), and levels of DPA and DHA were increased in liver and intestine of fish fed ECO compared to fish fed WCO likely due to increased LC-PUFA biosynthesis based on up-regulation of the genes. Fish fed WCO and ECO showed slight lipid accumulation within hepatocytes similar to that with WCO, although not significantly different to fish fed FO. The regulation of a small number of genes could be attributed to the specific effect of ECO (311 features) with metabolism being the most affected category. The EPA oil from transgenic Camelina (ECO) could be used as a substitute for FO, however it is a hybrid oil containing both FO (EPA) and VO (18:2n-6) fatty acid signatures that resulted in similarly mixed metabolic and physiological responses.
Project description:New de novo sources of omega 3 (n-3) long chain polyunsaturated fatty acids (LC-PUFA) are required as alternatives to fish oil in aquafeeds in order to maintain adequate levels of the beneficial fatty acids, eicosapentaenoic and docosahexaenoic (EPA and DHA, respectively). The present study investigated the use of an EPA+DHA oil derived from a transgenic Camelina sativa in feeds for Atlantic salmon (Salmo salar) containing low levels of fishmeal (35 %) and fish oil (10 %), reflecting current commercial formulations, to determine the impacts on intestinal transcriptome, tissue fatty acid profile and health of farmed salmon. Post-smolt Atlantic salmon were fed for 12-weeks with one of three experimental diets containing either a blend of fish oil/rapeseed oil (FO), wild-type camelina oil (WCO) or transgenic camelina oil (DCO) as added lipid source. The DCO diet did not affect any of the fish performance or health parameters studied. Analyses of the mid and hindgut transcriptomes showed only mild effects on metabolism. Flesh of fish fed the DCO diet accumulated almost double the amount of n-3 LC-PUFA than fish fed the FO or WCO diets, indicating that these oils from transgenic oilseeds offer the opportunity to increase the n-3 LC-PUFA in farmed fish to levels comparable to those found twelve years ago.
Project description:This study compared the transcriptome of salmon fed diets with different levels and/or composition of LC_PUFA. Feeds were formulated with either DHA (Docosahexaenoic acid) alone (either 1% of the diet or 2% of the diet) or with a combination of DHA and EPA (Eicosapentaenoic acid) or DHA and ARA (Arachidonic acid). NOTE: Two treatments used in this trial (1% DHA and 2% DHA) were also used in an experiment previously submitted (E-MTAB-3180). Specifically, arrays 62_3, 69_1, 67_1, 62_2, 70_4, 65_2, 76_4, 66_3, 73_3, 70_2.
Project description:The inclusion of intact phospholipids in the diet is essential during larval development and can improve culture performance of many fish species. The effects of supplementation of dietary phospholipid from marine (krill) or plant (soy lecithin) sources were investigated in Atlantic salmon, Salmo salar. First feeding fry were fed diets containing either krill oil supplying phospholipid at 2.6% of diet (named K2.6) or soybean lecithin supplying phospholipid at 2.6 % (S2.6), 3.6 % (S3.6) of diet. A control diet (B) without supplemented phospholipid was also supplied. Fish were sampled at ~ 2.5 g (~1990 ˚ day post fertilization, dpf) and ~10 g (2850 ˚dpf). By comparison of the intestinal transcriptome in specifically chosen contrasts, it was determined that by 2850˚dpf fish possessed a profile that resembled that of mature and differentiated intestinal cell types with a number of changes specific to glycerophospholipid metabolism. It was shown that intact phospholipids and particularly phosphatidylcholine are essential during larval development and that this requirement is associated with the inability of enterocytes in young fry to endogenously synthesize sufficient phospholipid for the efficient export of dietary lipid. In the immature phase (~1990 ˚dpf), the dietary phospholipid content as well as its class composition impacted on several biochemical and morphological parameters including growth, but these differences were not associated with differences in intestinal transcriptomes. The results of this study have made an important contribution to our understanding of the mechanisms associated with lipid transport and phospholipid biosynthesis in early life stages of fish.
Project description:Atlantic salmon (Salmo salar) has been selectively bred in Europe since the 1970s and the process of domestication has led to both phenotypic and genotypic differences between wild and farmed fish. Despite strict regulations large numbers of fish escape annually from fish farms, a concern for both aquaculturalists and those managing wild fish stocks. A better understanding of the interactions between domesticated and wild salmon is essential to the continued sustainability of the aquaculture industry and to the maintenance of healthy wild stocks. One major concern is that of potential interbreeding of escapees with wild fish leading to potentially detrimental genetic changes in wild populations. Advances in high throughput technologies allow the role of genome-wide gene transcription to be studied in relation to both micro- and macro- evolutionary change. In this study, we have compared the transcriptomes of Norwegian wild and domesticated stocks at two life stages: yolk sac and first-feeding salmon fry and reared under identical conditions. These preliminary data improve knowledge of potential transcriptional difference between domesticated and wild salmon and will hopefully provide a better understanding of the fitness consequences of such interactions.