1,721,029 research outputs found
Effect of the diet on the stress response to a simulated transportation experiment of fingerlings of Salmo marmoratus
No full textUnder intensive culture conditions, fish are subjected to increased stress that has negative impacts on the fish overall performance. Though good management practices contributes to reduce stressor effects, the possible role of the diet quality in modulating acute stress response has been poorly investigated in fish. The objective of this study was to evaluate the modulation of acute stress response by different diets in marbled trout, Salmo marmoratus. The results showed that a poor diet, beyond reducing growth and survival, can also affect fish acute stress response and that cortisol levels measured in non-invasive matrices such fins or skin mucus proved reliable to study acute stress response in marbled trout
Effects of long term feeding diets differing in protein source and pre-slaughter starvation on biometry, qualitative traits and liver IGF-I expression in large rainbow trout
Full text linkThe effects of feeding two complete extruded diets differing in protein source (fish meal-FM vs. vegetable proteins-VP) over 30 weeks and subsequent 30 days of starvation on biometry, fillet composition and liver IGF-I mRNNA were studied in large rainbow trout. At the end of the feeding period, the dietary protein source little affected major biometry traits, dressing out yields and overall adiposity (P>0.05) but fish given the VP diet resulted in higher content of PUFA n-6 fatty acids in muscle (0.46 vs. 0.22 g/100g fillet, P<0.05). Regardless of the previous diet, 30 days of starvation resulted in increased carcass yield (P<0.05), in a slight reduction in adiposity (P>0.05) and of all fatty acids in fillet (P<0.05), except DHA. Liver IGF-I mRNNA content was little affected by the test diet and starvation
WHEAT GLUTEN AS A PARTIAL SUBSTITUTE FOR FISH MEAL PROTEIN IN SEA BASS (D. LABRAX) DIETS.
No full textEffect of diets containing full-fat Hermetia illucens on rainbow trout microbiota: A dual cultivation-independent approach with DGGE and NGS
No full textGiven the drift to improve economic and ecological sustainability of the aquaculture sector, novel ingredients fulfilling these requirements are sought. Hermetia illucens, commonly called black soldier fly, (Diptera: Stratiomydae; H) is a promising dietary protein source but its effect on fish gut microbiota is still to be clarified. The aim of the present study was to increase the knowledge of the effect of dietary full-fat H meal on rainbow trout (Oncorhynchus mykiss) microbiota and, in particular, on intestinal mucosa-adherent microbiota by applying a dual approach based on polymerase chain reaction-denaturing gradient gel electrophoresis and high-throughput sequencing of the 16S rRNA gene. Rainbow trout (initial body weight of 137.3 ± 10.5 g) was fed for 98 days with a control diet (H0) containing fishmeal and protein-rich vegetable ingredients and an experimental diet (H50) where 50% of the fishmeal had been replaced by full-fat H meal rich in saturated fatty acids. Proteobacteria, Firmicutes and Actinobacteria were generally present in all samples, although the core microbiota (relative prevalence higher than or equal to 80% in all samples) only consisted of the proteobacteria Caulobacter, Delftia, Agrobacterium and Ochrobactrum. In addition, Streptococcus infantis and a member of the Cytophagaceae family were part of the core taxa of mucosa samples. Tenericutes were abundant in pyloric caeca samples and, among them, Mycoplasmataceae seemed to increase in the group fed the high saturated fatty acid diet containing H meal; a consideration about the connection between this bacterial group and the dietary lipid content must be considered. Dietary treatment did not clearly affect alpha-diversity metrics, but mucosa samples tended to be more resilient to dietary changes than content samples. Permutational analysis of variance showed significantly different β-diversities between diets (p < 0.05) but principal coordinates analysis did not confirm this result. Diets for rainbow trout containing full-fat H meal determined interesting modifications in the gut microbiota with patterns similar to the ones found in the literature. The dietary lipids can exert an effect on microbiota. Nonetheless, research data on this topic are still scarce and further studies are highly encouraged
A preliminary study on the degradation of AFB1 by Tenebrio molitor, Rhizopus oryzae and Trichoderma reesei
No full textRecently, genus Aspergillus, a fungus capable of producing aflatoxins, secondary highly toxic metabolites, has spread to new areas. These areas became suitable habitats due to the recent climate changes. The use of aflatoxin-contaminated crops is a cause of great concern in guaranteeing food safety and is responsible for major economic losses along the supply chain. For this reason, several strategies have been investigated to utilize these contaminated products as a possible food or feed resource by reducing or eliminating their aflatoxin content, but with limited relevant success. The presented study was aimed to evaluate a combination of biological processes to use aflatoxin B1 contaminated crops for their reintroduction into the production chain. The high tolerance to AFB1 and the apparent lack of accumulation in yellow mealworm larvae, reared on wheat bran substrates, spiked with increasing AFB1 concentration (0, 125, 250, 500 μg/kg) to obtain proteins of high biological value. Subsequently, the aflatoxin-degrading capacity of Rhizopus oryzae and Trichoderma reesei was applied to insect breeding waste (frass) in a fermentation process to ensure further utilization of biohazardous frass as soil conditioner. Individually, each process proven to be able to reduce the AFB1 present by about 80%, while the combination of the two approaches ensured the total degradation of aflatoxin B1-contaminated substrate and frass, which resulted in the possible production of biomass, that could be used for the feed and agricultural industry
Determination of the chemical characteristics of trout fillets by Near Infrared Reflectance Spectroscopy (NIRS)
No full textApparent nutrient digestibility of PAPs from poultry rendering and insect meals in rainbow trout (O. mykiss) and European seabass (D. labrax).
No full textRainbow Trout (Oncorhynchus mykiss) Skin as Potential n-3 Fatty Acid Source
No full textPurpose: The rise in the demand and the limited availability of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids claim to obtain these important long chain polyunsaturated fatty acids (LCPUFA) from novel sources. Skin of rainbow trout is a fish industry by-product but still contains valuable LCPUFA amounts with great potential applications in human nutrition and health. This study aimed to explore the nutritional composition of rainbow trout skin for its use as source of n-3 LCPUFA and its composition modification according to fish diet. Methods: Rainbow trout were fed three diets including increasing substitution levels of fishmeal with full-fat black soldier fly (Hermetia illucens) larvae meal (0%, 25%, 50% substitution levels) over 98 days. Results: DHA was the major representative of the n-3 LCPUFA in the skin of all dietary groups, being the H25 group the richest in this fatty acid. Conclusions: The present study shows that the skin of rainbow trout can be a promising source of n-3 LCPUFA. Reusing the skin of farmed fish represents a possible way to decrease food industry by-products, to reduce n-3 LCPUFA shortfall and could lead to the development of functional foods and nutritional supplements including n-3 LCPUFA from fish skin. Graphic Abstract: [Figure not available: see fulltext.
Prediction of chemical composition and origin identification of European sea bass (Dicentrarchus labrax L.) by near infrared reflectance spectroscopy (NIRS)
No full textNear infrared reflectance spectroscopy (NIRS) analysis was used to predict proximate chemical composition and identify the rearing system of 236 European sea bass caught in four Italian fish farms (extensive ponds, semi-intensive ponds, intensive tanks and intensive sea-cages). Three types of sample preparation (intact fillet portions; whole fresh minced fillet; freeze-dried minced fillet) were compared. NIRS provided good reliability in the prediction of chemical composition of sea bass fillets but weaker results in crude protein prediction. NIRS prediction of chemical composition proved to be more accurate with fresh minced fillets than intact fillet portions. The merely slight improvement of NIRS accuracy with freeze-dried samples did not justify the latter treatment, which was necessary, however, to obtain reliable information on the sea bass rearing system
. The effects of coconut oil on reproductive traits and fatty acid eggcomposition of rainbow Oncorhynchus mykiss, Walbaum)
Full text linkTwo hundred and twenty rainbow trouts (IBW: 700 g) were randomly allotted to four tanks,
with a male/female ratio of 0.56. Fish were fed for 168 d with four experimental diets containing herring
oil, cod liver oil and coconut oil with the following inclusion rates: diet A: 12-1-0% respectively;
diet B: 6-1-6%; diet C: 0-1-12%; diet D: 0-0-13%. Irrespective of the dietary treatment, weight gains of
broodstocks were high (> 3 g/d) and FCR below 2. No significant difference was observed concerning
the total amount of eggs spawn, egg average weight (82.5 mg/egg) and lipid content (5.4 mg/egg).
However, the fatty acid profile of eggs was significantly affected by the dietary treatments. The content
of unsaturated fatty acids, particularly the n-3 fatty acid series (EPA and DHA) significantly decreased
with increasing levels of coconut oil in the diet
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