Salmonids on Insect Protein – Impact on Performance and Health
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ABSTRACT: In order to find out whether insects are suitable as a pure protein source and what potential problems or benefits can be expected, a 10-week feeding experiment was set up. In this experiment, the overall protein content were identical, while the protein content from soy and fishmeal was replaced with 25, 50, 75 and 100% insect meal. In order to evaluate the effect of the insect protein on the fish, fish size and weight were determined at the beginning and end of the experiment, and transcriptomic analyses of proximal intestine were performed. Finally, samples of the liver and intestine were examined histologically.
Project description:Rainbow trout (Oncorhynchus mykiss) and other salmonids are piscivorous fish. In aquaculture, fish-based feed ingredients are rapidly becoming unsustainable due to increased demand and diminishing supply. Total replacement of fishmeal with plant proteins causes severe intestinal enteritis, leading to reduced growth and lower feed efficiency. Through selective breeding, we have developed a strain of rainbow trout that does not develop distal intestine enteritis when reared on a high soy plant protein-based feed and also shows increased growth compared to other strains. Since central metabolism plays a major role in dietary alterations, and as growth was a major factor in the selection program, both muscle and liver gene expression were examined for differential regulation between commercial and selected trout strains when fed alternative diets. After three months of rearing on either a fishmeal (FM) or plant protein-based (PM) diet, muscle and liver tissues from a domestic non-selected strain (House Creek; develops enteritis) and the selected strain (ARS-KO; no enteritis) were extracted and prepped for Illumina RNA-seq. Raw reads were screened for quality then aligned to the rainbow trout transcriptome. Read-counts were used to assess differential expression between strains and treatments. Significant differentially expressed genes between comparisons were assessed.
Project description:Purpose: By-products from farmed fish contain large amounts of proteins and may be used for human consumption. The purpose of this study was to investigate cardiometabolic effects and metabolic tolerance in mice consuming fishmeal from salmon by-products, salmon filet or beef. Methods: Female C57BL/6J mice were fed chow, as a healthy reference group, or a high-fat diet for 10 weeks to induce obesity and glucose intolerance. Obese mice were subsequently given isocaloric diets containing 50% of the dietary protein from salmon fishmeal, salmon filet or beef for 10 weeks. Mice were subjected to metabolic phenotyping, which included measurements of body composition, energy metabolism in metabolic cages and glucose tolerance. Lipid content and markers of hepatic toxicity were determined in plasma and liver. Hepatic gene and protein expression was determined with RNA sequencing and immunoblotting. Results: Mice fed fishmeal, salmon filet or beef had similar food intake, energy consumption, body weight gain, adiposity, glucose tolerance and circulating levels of lipids and hepatic toxicity markers, such as p-ALT and p-AST. Fishmeal increased hepatic cholesterol levels by 35-36% as compared to salmon filet (p = 0.0001) and beef (p = 0.005). This was accompanied by repressed expression of genes involved in steroid and cholesterol metabolism and reduced levels of circulating Pcsk9. Conclusion: Salmon fishmeal was well tolerated, but increased hepatic cholesterol content. The high cholesterol content in fishmeal may be responsible for the effects on hepatic cholesterol metabolism. Before introducing fishmeal from salmon by-products as a dietary component, it may be advantageous to reduce the cholesterol content in fishmeal.
Project description: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 present study was conducted to investigate the effect of graded levels of black soldier fly larvae (BSFL) (Hermetia illucens) meal and BSFL paste in extruded diets for Atlantic salmon (Salmo salar). A total of 1260 Atlantic salmon with 34 g of mean initial weight were randomly distributed into 21 fiberglass tanks and fed (n=3) with seven extruded isolipidic and isonitrogenous diets for seven weeks. The experimental diets consisted of a positive control diet based on fishmeal, soy protein concentrate, corn gluten, faba bean and fish oil (Control_1); three diets with increased levels of full lipid BSFL meal, substituting 6.25% (6.25_IM), 12.5% (12.5_IM) and 25% (25_IM) of the protein content of Control_1; two diets with increased levels of full lipid BSFL paste, substituting 3.7% (3.7_IP) and 6.7% (6.7_IP); and of protein from Control_1 and a negative a control with 0.84 % of formic acid (Control_2). We investigate the effect of diets on growth performance, mmune response and health.
Project description:Background: The decreasing availability of fishmeal as a protein source in aquaculture diets will require aquaculture to develop an econmoical and sustainable protien replacement. Plant proteins are readily available and are being tested as a promising alternative to replace a substantial portion of fishmeal which currently provides most of the protein content in aquaculture diets. The types of plant protein feasible for incorporation into aquaculture diets will likely contain various anti-nutritional compounds, carbohydrates, fiber, and a different amino acid profile than what is found in fishmeal. Substantial genetic variation was previously observed for growth on plant based dits in rainbow trout Hence, it will be beneficial to identify metabolic and physiologic pathways related to enhanced plant protein utilization which will aid in identifying genes that contribute to this genetic variation. Results: Microarray analysis of liver samples from two families of rainbow trout that differed in their growth responses when compared between individuals grown on a fish meal or plant protein based diet. Differential expression relating to dietary utilization between the two families found significant changes in expression of 33 ESTs. Eight of the differntially expressed ESTs had identified mammalian homologs that had been previously researched with identified cellular interactions and functions. Conclusions: Utilizing pathway analysis software to analyze sequences annotated with known mammalian genes were were ablet o map gene pathway and process interactions. From this information we were able to infer that the metabolic changes associated with utilization of plant protein versus fishmeal were associated with differential reaulation of genes related to cell oxidative stress, proliferation, growth, and survival. Furthermore, we inferred from the changes we observed in immune response genes expression that ingestion of this plant based diet upregulated the expression of genes involved in immunoregulatroy processes. Genotyped samples linked to families that had 4 or more members sampled on each diet were identified and ranked according to average family weight on each diet. Size rankings corresponded to large (>750 g), medium (600-640 g), and small (<500 g). From these identified groups 2 families were chosen for microarray expression analysis that demonstrated individuals with growth differences between the two diets. Data for the two families used for analysis and slide arrangements are listed in table 3. The families compared for growth differences between diets used for this study only differed by one growth range, large fish on fish meal compared to medium fish on plant-based diet and medium sized fish on fishmeal diet compared to small fish on plant-based diet. This strategy to use size separation within family was an attempt to identify gene changes more specific to diet utilization than specific for growth differences.
Project description:The present work studies the effect of Debaryomyces hansenii yeast-based products on physiological responses in Atlantic salmon exposed to a short-term stress. For this, a control fishmeal-based diet (CD) and experimental diets containing 0.1% of Debaryomyces hansenii were fed to fish for 8 weeks in fresh water. At the end of the feeding experiment, fish were exposed to 1-minute hypoxia stress and samples were collected post-stress
Project description:Rainbow trout (Oncorhynchus mykiss) and other salmonids are piscivorous fish. In aquaculture, fish-based feed ingredients are rapidly becoming unsustainable due to increased demand and diminishing supply. Total replacement of fishmeal with plant proteins causes severe intestinal enteritis, leading to reduced growth and lower feed efficiency. Through selective breeding, we have developed a strain of rainbow trout that does not develop distal intestine enteritis when reared on a high soy plant protein-based feed and also shows increased growth compared to other strains. Since central metabolism plays a major role in dietary alterations, liver RNA was examined for differential expression of long non-coding RNAs (lncRNAs) between commercial and selected trout strains when fed an alternative diet. These types of non-coding RNA have been previously shown to have a potential role in regulation of gene expression; however, most identified lncRNAs have not been functionally characterized and/or lack definition in many non-model organisms. Their roles in gene regulation and their responsiveness to dietary changes in trout are to be explored. After three months of rearing on a plant protein-based (PM) diet, liver tissues from a domestic non-selected strain (House Creek; develops enteritis) and the plant-diet tolerant selected strain (ARS-KO; no enteritis) were extracted and prepped for Illumina RNA-seq. Raw reads were screened for quality then assembled into transcripts using Trinity. Assembled transcripts were then submitted to the Annocript pipeline to determine their potential as lncRNAs. RNA-seq reads were mapped to putative lncRNAs. Read-counts were used to assess differential expression between strains.
Project description:Background: The decreasing availability of fishmeal as a protein source in aquaculture diets will require aquaculture to develop an econmoical and sustainable protien replacement. Plant proteins are readily available and are being tested as a promising alternative to replace a substantial portion of fishmeal which currently provides most of the protein content in aquaculture diets. The types of plant protein feasible for incorporation into aquaculture diets will likely contain various anti-nutritional compounds, carbohydrates, fiber, and a different amino acid profile than what is found in fishmeal. Substantial genetic variation was previously observed for growth on plant based dits in rainbow trout Hence, it will be beneficial to identify metabolic and physiologic pathways related to enhanced plant protein utilization which will aid in identifying genes that contribute to this genetic variation. Results: Microarray analysis of liver samples from two families of rainbow trout that differed in their growth responses when compared between individuals grown on a fish meal or plant protein based diet. Differential expression relating to dietary utilization between the two families found significant changes in expression of 33 ESTs. Eight of the differntially expressed ESTs had identified mammalian homologs that had been previously researched with identified cellular interactions and functions. Conclusions: Utilizing pathway analysis software to analyze sequences annotated with known mammalian genes were were ablet o map gene pathway and process interactions. From this information we were able to infer that the metabolic changes associated with utilization of plant protein versus fishmeal were associated with differential reaulation of genes related to cell oxidative stress, proliferation, growth, and survival. Furthermore, we inferred from the changes we observed in immune response genes expression that ingestion of this plant based diet upregulated the expression of genes involved in immunoregulatroy processes.
Project description:The sustainable development of modern aquaculture must rely on a significant reduction of the fish meal (FM) used in aquafeed formulations. However, FM substitution with alternative ingredients in diets for carnivorous fish species often showed reduced nutrient absorption, significantly perturbed metabolisms and histological changes at both hepatic and intestinal level. In the present study, adult rainbow trout (Oncorhynchus mykiss) were fed three different experimental aquafeed formulations. A control diet with higher FM content (27.3%) than two test formulations in which fish meal was substituted with two more sustainable and promising alternatives: insect meal (Hermetia illucens larvae=10.1%, FM=11.6%) and poultry by-products meal (PBM=14.8%; FM=11.7%). Combined metabolomics and proteomics analyses of fish liver, together with histological examination of liver and intestine demonstrated that a well balanced formulation of nutrients in the three diets allowed high metabolic compatibility of either substitutions, paving the way for innovative and sustainable use of novel raw materials for the fish feed industry. Results show that the main metabolic pathways of nutrient absorption and catabolism were essentially unaltered by alternative feed ingredients, and also histological alterations were negligible. It is demonstrated that substitution of fish meal with sustainable alternatives does not impact on fish metabolism, given proper efforts are put in fulfilling nutritional requirements of rainbow trout.