Survival, Growth Performance, and Hepatic Antioxidant and Lipid Profiles in Infected Rainbow Trout (Oncorhynchus mykiss) Fed a Diet Supplemented with Dihydroquercetin and Arabinogalactan.

Natural feed supplements have been shown to improve fish viability, health, and growth, and the ability to withstand multiple stressors related to intensive cultivation. We assumed that a dietary mix of plant-origin substances, such as dihydroquercetin, a flavonoid with antioxidative, anti-inflammatory, and antimicrobial properties, and arabinogalactan, a polysaccharide with immunomodulating activity, would promote fish stress resistance and expected it to have a protective effect against infectious diseases. Farmed rainbow trout fish, Oncorhynchus mykiss, received either a standard diet or a diet supplemented with 25 mg/kg of dihydroquercetin and 50 mg/kg of arabinogalactan during a feeding season, from June to November. The fish in the control and experimental groups were sampled twice a month (eight samplings in total) for growth variable estimations and tissue sampling. The hepatic antioxidant status was assessed via the quantification of molecular antioxidants, such as reduced glutathione and alpha-tocopherol rates, as well as the enzyme activity rates of peroxidase, catalase, and glutathione-S-transferase. The lipid and fatty acid compositions of the feed and fish liver were analyzed using thin-layer and high-performance liquid chromatography. The viability, size, and biochemical indices of the fish responded to the growth physiology, environmental variables such as the dissolved oxygen content and water temperature, and sporadic factors. Due to an outbreak of a natural bacterial infection in the fish stock followed by antibiotic treatment, a higher mortality rate was observed in the fish that received a standard diet compared to those fed supplemented feed. In the postinfection period, reduced dietary 18:2n-6 and 18:3n-3 fatty acid assimilation contents were detected in the fish that received the standard diet in contrast to the supplemented diet. By the end of the feeding season, an impaired antioxidant response, including reduced glutathione S-transferase activity and glutathione content, and a shift in the composition of membrane lipids, such as sterols, 18:1n-7 fatty acid, and phospholipids, were also revealed in fish fed the standard diet. Dietary supplementation with plant-origin substances, such as dihydroquercetin and arabinogalactan, decreases lethality in fish stocks, presumably though the stimulation of natural resistance in farmed fish, thereby increasing the economic efficacy during fish production. From the sustainable aquaculture perspective, natural additives also diminish the anthropogenic transformation of aquaculture-bearing water bodies and their ecosystems.

Tissue Lipid Profiles of Rainbow Trout, Oncorhynchus mykiss, Cultivated under Environmental Variables on a Diet Supplemented with Dihydroquercetin and Arabinogalactan.

Reared rainbow trout are vulnerable to environmental stressors, in particular seasonal water warming, which affects fish welfare and growth and induces a temperature response, which involves modifications in tissue lipid profiles. Dietary supplements of plant origin, including the studied mix of a flavonoid, dihydroquercetin and a polysaccharide, arabinogalactan (25 and 50 mg per 1 kg of feed, respectively), extracted from larch wood waste, were shown to facilitate stress tolerance in fish and also to be beneficial for the safety of natural ecosystems and the sustainability of aquaculture production. This four-month feeding trial aimed to determine the effects of the supplement on liver and muscle lipid accumulation and the composition in rainbow trout reared under environmental variables. During periods of environmental optimum for trout, a consistent increase in energy lipid stores, particularly triacylglycerols (2.18 vs. 1.49-fold over a growing season), and an overall increase in lipid saturation due to lower levels of PUFAs, such as eicosapentaenoic (20:5n-3), docosahexaenoic (22:6n-3) and arachidonic (20:4n-6) acids, were observed in both control and supplement-fed fish, respectively. However, in fish stressed by an increase in ambient temperature, dietary supplementation with dihydroquercetin and arabinogalactan reduced mortality (3.65 in control vs. 2.88% in supplement-fed fish, p < 0.05) and alleviated the high-temperature-induced inhibition of lipid accumulation. It also stabilised the membrane phospholipid ratio and moderated the fatty acid composition of fish muscle and liver, resulting in higher levels of n-3 PUFAs and their precursors. Thus, the natural compounds tested are beneficial in accelerating fish tolerance to environmental stressors, reducing mortality and thermal response, and moderately improving fillet quality attributes by increasing the protein/lipid ratio and the abundance of fatty acids essential for human nutrition.

Infection and antibiotic treatment have prolonged effects on gut microbiota, muscle and hepatic fatty acids in rainbow trout (Oncorhynchus mykiss).

AIMS: The aim of the present study was to investigate the gastrointestinal (GI) microbiota and bacterium-specific fatty acid occurrence in the muscle and hepatic lipids of rainbow trout Oncorhynchus mykiss (Walbaum, 1792), both healthy and those naturally infected with bacterial pathogens. METHODS AND RESULTS: From June 2017 (L1) to September 2018 (L8), 74 specimens of rainbow trout Oncorhynchus mykiss (with an average weight from 139.2 ± 7.1 g (L1) to 2191.7 ± 85.1 g (L8)) were studied. Amplicon sequencing targeted to the V3-V4 region of 16S rRNA gene fragments is used for the identification of the taxonomic composition of gut bacterial communities. Firmicutes, Bacteroidetes, Proteobacteria, Tenericutes and Fusobacteria were the major phyla. Besides behavioural and physiological manifestations of the bacterial mixed disease (yersiniosis, pseudomonosis and flavobacteriosis), some disorders induced by both the infection and followed antibiotic treatment were detected in the host organism, including (1) a progressive decrease in the content of odd-chain saturated fatty acids of bacterial origin within the trout lipid molecules and (2) abnormalities in trout GI tract microbiota, such as the elimination of LAB and progressive occurrence of certain bacterial taxa, particularly Mycoplasmataceae. CONCLUSIONS: The GI bacterial flora varied principally due to Mycoplasmataceae and Lactobacillaceae, which could be considered in the search for bioindicators. The content of specific bacterium-derived fatty acids incorporated into the lipids of trout muscle and hepatic seems to be related to the prevalence of bacterial taxa, and their deficit could be regarded as an early warning sign of microbiota disturbance. SIGNIFICANCE AND IMPACT OF STUDY: Our results demonstrated that infectious disease and antibiotic treatment of reared species can cause a pertinent imbalance in their gut microbiota and reduce the abundance of specific fatty acids. This can be useful for the sustainable aquaculture industry due to the development of early indication technologies for rapid disease diagnosis.

Taxifolin Modulates Transcriptomic Response to Heat Stress in Rainbow Trout, Oncorhynchus mykiss.

Taxifolin is a natural flavonoid known for its antioxidant, anti-inflammatory, and antiproliferative effects on animals. In this work, we have studied the effect of this compound on rainbow trout, Oncorhynchus mykiss, a major object of aquaculture, under slowly increasing ambient temperature and Gyrodactylus flatworm infection. Transcriptomic profiling of liver samples performed by using the Illumina HiSeq 2500 sequencing platform shows that a combined taxifolin/heat treatment, unlike heat treatment alone, downregulates the production of isopentenyl diphosphate, likely affecting the production of cholesterol and other sterols. Taxifolin treatment also modulates multiple apoptosis regulators and affects the expression of HSPs in response to increasing temperature. On the other hand, the expression of antioxidant enzymes in response to heat is not significantly affected by taxifolin. As for the Gyrodactylus infection, the parasite load is not affected by taxifolin treatment, although it was lower in the high-temperature group. Parasite load also did not induce a statistically significant transcriptomic response within the no heat/no taxifolin group.

Dataset on body weight and length of rainbow trout, Oncorhynchus mykiss, fed with dihydroquercetin, arabinogalactan or a mixture of both in an aquaria experiment.

The use of natural dietary supplements in aquaculture has received a great deal of attention in recent years. This article provides data describing body weight and length of rainbow trout juveniles fed with natural dietary supplements dihydroquercetin, arabinogalactan or a mixture of both in an aquaria experiment. Before feeding trial, rainbow trout were tagged to identify individuals. Fish grown in tanks were fed one of four diets in duplicate: a basal diet without any supplements (control diet) or a basal diet supplemented with dihydroquercetin (experimental diet 1), arabinogalactan (experimental diet 2) or a mixture of both (experimental diet 3). Our dataset could be used to evaluate the effect of dihydroquercetin, arabinogalactan or a mixture of both on the growth performance of cultivated rainbow trout.

Melatonin-Responsive Complex Nocturnal Visual Hallucinations.

ABSTRACT: Complex nocturnal visual hallucinations are vivid, dramatic, intricate visual hallucinations occurring during sleep onset or awakenings at night, generally lasting for a few minutes at most and disappearing with increased levels of light. They may occur in a number of neurological conditions, as well as in normal individuals. The optimal treatment for this condition remains unclear. We describe three patients with complex nocturnal visual hallucinations in whom melatonin brought about a dramatic improvement in symptoms. Our report suggests that melatonin may be a safe, effective treatment for this rare but often distressing and anxiety-provoking condition.

Skeletal muscle protease activities in the early growth and development of wild Atlantic salmon (Salmo salar L.).

Growth-related dynamics of intracellular protease activities in four year classes of the Atlantic salmon (Salmo salar L. 1758) parr and smolts inhabiting salmon rivers of northwestern Russia (the White Sea basin) were studied. Cathepsin B, cathepsin D, proteasome, and calpain activities in the skeletal muscles of salmon were assessed to investigate their relative contribution to the total protein degradation as well as to young fish growth process. It was confirmed that calpain activity dominates in salmon muscles while proteasome plays a minor role, in contrast to terrestrial vertebrates. Calpain and proteasome activities were maximal at the early post-larval stage (in parrs 0+) and declined with age (parrs 1+ through 2+) dropping to the lowest level in salmon smolts. Annual growth increments and proteolytic activities of calpains and proteasome in the muscles of salmon juveniles changed with age in an orchestrated manner, while lysosomal cathepsin activities increased with age. Comparing protease activities and growth increments in salmon parr and smolts we suggested that the partial suppression of the protein degradation could be a mechanism stimulating efficient growth in smoltifying salmon. Growth and smoltification-related dynamics of protease activities was quite similar in salmon populations from studied spawning rivers, such as Varzuga and Indera; however, some habitat-related differences were observed. Growth increments and protease activities varied in salmon parr 0+ (but not on later ages) inhabiting either main rivers or small tributaries apparently due to habitat difference on the resources for fish growth.

Protein degradation systems in the skeletal muscles of parr and smolt Atlantic salmon Salmo salar L. and brown trout Salmo trutta L.

Although protein degradation limits the rate of muscle growth in fish, the role of proteolytic systems responsible for degrading myofibrillar proteins in skeletal muscle is not well defined. The study herein aims to evaluate the role of calpains (calcium-activated proteases) and proteasomes (ATP-dependent proteases) in mediating muscle protein turnover at different life stages in wild salmonids. Protease activities were estimated in Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.) parr and smolts from the Indera River (Kola Peninsula, Russia). Calpain and proteasome activities in Atlantic salmon skeletal muscles were lower in smolts as compared with parr. Reduced muscle protein degradation accompanying Atlantic salmon parr-smolt transformation appeared to provide intense muscle growth essential for a minimum threshold size achievement that is required for smoltification. Calpain and proteasome activities in brown trout parr and smolts at age 3+ did not significantly differ. However, calpain activity was higher in smolts brown trout 4+ as compared with parr, while proteasome activity was lower. Results suggest that brown trout smoltification does not correspond with intense muscle growth and is more facultative and plastic in comparison with Atlantic salmon smoltification. Obtained data on muscle protein degradation capacity as well as length-weight parameters of fish reflect differences between salmon and trout in growth and smoltification strategies.

The efficacy of a chinstrap in treating sleep disordered breathing and snoring.

STUDY OBJECTIVES: A previously published case report suggested that a chinstrap alone might improve obstructive sleep apnea (OSA). We conducted this study to determine whether a chinstrap was a feasible alternative to continuous positive airway pressure (CPAP) in patients with OSA. METHODS: 26 adult patients with OSA (apnea-hypopnea index [AHI] > 5/h on diagnostic polysomnogram [PSG]) underwent a modified split-night PSG, using only a chinstrap for the first 2 hours of sleep, followed by CPAP titration for the remainder of the night. Improvements in AHI, arterial oxygen saturation (SpO2), and snoring with chinstrap use were compared to results with optimal CPAP pressures. RESULTS: There was no significant difference between the diagnostic PSG and the chinstrap portion of the split-night PSG in the following parameters: general AHI (median [IQR] 16.0/h [9.7-26.0] vs. 25.9/h [10.7-42.7]), SpO2 nadir (84.0% [80.5-87.5] vs. 87.0 [84.0-88.5]), AHI in REM sleep (26.7/h [16.8-43.7] vs. 42.4/h [21.3-57.7]), AHI in supine sleep (24.9/h [11.9-51.5] vs. 29.8/h [11.7-55.5]), snoring index (253.2/h [147.5-353.1] vs. 180.0/h [9.8-393.3]) or subjective snoring scale (3.0 [0.8-3.0] vs. 2.5 [0.4-3.0]). The AHI and SpO2 nadir in the 13 patients with mild OSA also did not improve with chinstrap use (9.6/h [8.1-12.2] vs. 10.6/h [6.8-35.4] and 87.0% [83.0-90.0] vs. 88.0% [87.0-89.0]). All these parameters showed significant improvement with optimal CPAP titration (p < 0.05). CONCLUSIONS: A chinstrap alone is not an effective treatment for OSA. It does not improve sleep disordered breathing, even in mild OSA, nor does it improve the AHI in REM sleep or supine sleep. It is also ineffective in improving snoring.

Biochemical markers of pollutant responses in macrozoobenthos from the White Sea: intracellular proteolysis.

Coastal environments of Kandalaksha Gulf in the White Sea (Russia) despite nature conservation efforts are heavily influenced by human activities. Biological effects of complex environmental pollution, including organic substances, heavy metals, and oil hydrocarbons, were assessed in widely distributed marine invertebrates, Gammarus duebeni (Crustacea, Amphipoda) and Mytilus edulis (Mollusca, Bivalvia), collected from a series of anthropogenically-impacted areas and distanced reference sites in Kandalaksha Gulf. The parameters of intracellular protein degradation pathways such as cytosol calpain system and lysosomal cathepsins B (CatB) and cathepsin D (CatD) were studied. The response reactions observed in invertebrates vary in specificity and ranged from adaptive to destructive depending on the total contaminant level and the nature of predominant pollutant. The ecological relevance of studied parameters as biomarkers was confirmed by their ability to indicate both expose to pollutants and adverse effects at the organism level.

Increasing off-time improves sleep-disordered breathing induced by vagal nerve stimulation.

Vagal nerve stimulation (VNS) has been reported to adversely impact breathing in sleep. While continuous positive airway pressure is often employed to treat these patients, little data exist on the effects of adjusting various settings on VNS-induced sleep-disordered breathing. We describe a patient in whom increasing off-time caused resolution of VNS-induced arterial oxygen desaturations in sleep, which we believe is a novel observation.

Effect of copper and cadmium ions on heart function and calpain activity in blue mussel Mytilus edulis.

The heart rate and calpain activity of blue mussels Mytilus edulis from the sublittoral zone, exposed to different levels of water-borne copper and cadmium, was investigated in a long-term experiment. The content of cadmium and copper in the blue mussel was determined using flame and graphite Atomic absorption spectroscopy. The observed concentrations ranged from 2.5 to 89.1 µg/g dry weight for cadmium and from 6.1 to 51.0 µg/g dry weight for copper in the control and highest concentration, respectively. Initially, increase in cardiac activity in response to copper and Cadmium exposure was observed under all pollutant concentrations (5-250 and 10-500 µg/L, respectively). The calpain-like activity in gills and hepatopancreas of the mussels treated with metals changed in dose- and time-dependent manner: from a sharp rise at the 250 µg/L concentration of copper on the first day to a significant decrease under the effect of Cadmium in the concentration of 500 µg/L on the third day of the experiment. These results suggest that: (i) heart rate oscillation may reflect active adaptation of blue mussels to contamination and (ii) animals have different sensitivity to copper and Cadmium according to the role of the metals in the mussels' life activity.