Effects of dietary supplementation of chitosan-oligosaccharides （COS） on the growth performance, immune response, stress resistance, and disease resistance of juvenile rainbow trout Oncorhynchus mykiss were studied....Effects of dietary supplementation of chitosan-oligosaccharides （COS） on the growth performance, immune response, stress resistance, and disease resistance of juvenile rainbow trout Oncorhynchus mykiss were studied. Four experimental diets containing 0, 20, 40, or 60 mg/kg COS （COSO, COS20, COS40, and COS60, respectively） were fed to juvenile rainbow trout （initial weight = 5.2 ± 0.3 g） for 8 weeks. By the end of the feeding trial, representative groups of fish from each dietary treatment were challenged with stressor （30 see air exposure） and pathogen exposure （intraperitoneal injection with Aeromonas hydrophila ）. Results showed that supplementation of COS in diets did not affect production performance and body composition of rainbow trout. However, fish fed the COS40 diet demonstrated improved phagocytic activities, respiratory burst activities and decreased serum cortisol level. Additionally, survival following A. hydrophila challenge was significant higher among fish fed the COS-supplemented feeds, although there was no difference based on the level of supplementation. The present study suggests that COS can be used as an immuno-stimulant in rainbow trout feeds展开更多
The inclusion of PepSoyGen (PSG), a commercially-available fermented soybean meal product, was evaluated with juvenile rainbow trout, Oncorhynchus mykiss in an initial 70-day feeding trial, with a supplemental trial i...The inclusion of PepSoyGen (PSG), a commercially-available fermented soybean meal product, was evaluated with juvenile rainbow trout, Oncorhynchus mykiss in an initial 70-day feeding trial, with a supplemental trial involving a subset of the experimental diets continuing for an additional 40 d. Six diets containing 0%, 10%, 20%, 30%, 40%, or 50% PSG, with the PSG directly replacing fish meal, were used in the first trial. There were no significant differences in weight gain or feed conversion ratio between the fish meal-based control diet and diets containing up to 30% PSG. However, weight gain was significantly reduced and feed conversion ratio significantly increased with the 40% and 50% PSG diets. No health assessment differences were observed in fish receiving any of the diets, and no evidence of gross gut inflammation was evident. There were no significant differences in weight gain or feed conversion ratio among the four dietary treatments ranging from 0% to 30% PSG which were fed for an additional 40 d after the initial 70-d trial (110 days total). Based on these results, juvenile rainbow trout diets can contain up to 30% PSG without any loss of rearing performance, thereby replacing at least 60% of the fish meal.展开更多
Background:Aquaculture must continue to reduce dependence on fishmeal(FM)and fishoil in feeds to ensure sustainable sector growth.Therefore,the use of novel aquaculture feed ingredients is growing.In this regard,insec...Background:Aquaculture must continue to reduce dependence on fishmeal(FM)and fishoil in feeds to ensure sustainable sector growth.Therefore,the use of novel aquaculture feed ingredients is growing.In this regard,insects can represent a new world of sustainable and protein-rich ingredients for farmed fish feeds.Accordingly,we investigated the effects of full replacement of FM with Tenebrio molitor(TM)larvae meal in the diet of rainbow trout(Oncorhynchus mykiss)on fish gut and skin microbiota.Methods:A feeding trial was conducted with 126 trout of about 80 g mean initial weight that were fed for 22 weeks with two isonitrogenous,isolipidic,and isoenergetic extruded experimental diets.Partially defatted TM meal was included in one of the diets to replace 100%(TM 100)of FM,whereas the other diet(TM 0)was without TM.To analyse the microbial communities,the Illumina MiSeq platform for sequencing of 16S rRNA gene and Qiime pipeline were used to identify bacteria in the gut and skin mucosa,and in the diets.Results:The data showed no major effects of full FM substitution with TM meal on bacterial species richness and diversity in both,gut mucosa-and skin mucus-associated microbiome.Skin microbiome was dominated by phylum Proteobacteria and especially by Gammaproteobacteria class that constituted approximately half of the bacterial taxa found.The two dietary fish groups did not display distinctive features,except for a decrease in the relative abundance of Deefgea genus(family Neisseriaceae)in trout fed with insect meal.The metagenomic analysis of the gut mucosa indicated that Tenericutes was the most abundant phylum,regardless of the diet.Specifically,within this phylum,the Mollicutes,mainly represented by Mycoplasmataceae family,were the dominant class.However,we observed only a weak dietary modulation of intestinal bacterial communities.The only changes due to full FM replacement with TM meal were a decreased number of Proteobacteria and a reduced number of taxa assigned to Ruminococcaceae and Neisseriaceae families.Conc展开更多
N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine quinone(6PPDQ)has attracted significant attention due to its highly acute lethality to sensitive salmonids.However,studies investigating the mechanisms underlying it...N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine quinone(6PPDQ)has attracted significant attention due to its highly acute lethality to sensitive salmonids.However,studies investigating the mechanisms underlying its acute toxicity have been lacking.In this work,we demonstrated the sensitivity of rainbow trout to 6PPDQ-induced mortality.Moribund trout exhibited significantly higher brain concentrations of 6PPDQ compared to surviving trout.In an in vitro model using human brain microvascular endothelial cells,6PPDQ can penetrate the blood–brain barrier and enhance blood–brain barrier permeability without compromising cell viability.The time spent in the top of the tank increased with rising6PPDQ concentrations,as indicated by locomotion behavior tests.Furthermore,6PPDQ influenced neurotransmitter levels and m RNA expression of neurotransmission-related genes in the brain and exhibited strong binding affinity to target neurotransmission-related proteins using computational simulations.The integrated biomarker response value associated with neurotoxicity showed a positive linear correlation with trout mortality.These findings significantly contribute to filling the knowledge gap between neurological impairments and apical outcomes,including behavioral effects and mortality,induced by6PPDQ.展开更多
Juvenile rainbow trout Oncorhynchus mykiss were subjected to one of four treatments in a two-by-two experimental design: 1) fed at a density of 1.8 g/m<sup>3</sup>, 2) Fasted at 1.8 g/m<sup>3</sup...Juvenile rainbow trout Oncorhynchus mykiss were subjected to one of four treatments in a two-by-two experimental design: 1) fed at a density of 1.8 g/m<sup>3</sup>, 2) Fasted at 1.8 g/m<sup>3</sup>, 3) fed at 30.1 g/m<sup>3</sup>, and 4) fasted at 30.1 g/m<sup>3</sup>. Blood glucose and hematocrit were measured at 4, 6, 48, 168, and 336 hours after placement in one of the two rearing densities, with relative fin lengths and organosomatic indices recorded at 336 hours. Glucose levels over time were not significantly different among the density and feeding treatments. Hematocrit levels over time were also not significantly different. Total lengths, weight, hepatosomatic index, viscerosomatic index, and any of the relative fin lengths were not significantly different between the high and low densities. However, the hepatosomatic index was significantly greater in the fed fish compared to those fasted. The splenosomatic index was significantly greater in the higher density treatment. These results likely indicate no short-term stress response to the higher rearing density used in this short-term experiment and no interaction between starvation and density-related stressors.展开更多
Decabromodiphenyl ether （BDE209） is the primary component in a commonly used flame retardant. Previous studies had proved that BDE209 itself was not toxic, while its metabolites including debrominated diphenyl ethe...Decabromodiphenyl ether （BDE209） is the primary component in a commonly used flame retardant. Previous studies had proved that BDE209 itself was not toxic, while its metabolites including debrominated diphenyl ethers （De-BDEs） and methoxylated brominated diphenyl ethers （MeO-BDEs） posed a potential threat to organisms. Many studies had indicated that BDE209 could metabolize quickly in mammals, but lacking in the basic data about the metabolism of BDE209 in fish. In the present study, two replicate treatment groups of rainbow trout （Oncorhynchus rnykiss） were exposed to BDE209 via a single intraperitoneal injection approximately 100 and 500 ng/g, respectively. Muscle, liver and blood samples were collected to analyze the specific metabolites on day 1 and day 28 post injection. The highest concentration of BDE209 was detected in muscle tissues, from 796.1 ng/g wet weight （day 1） to 687.1 ng/g wet weight （day 28） in high dose group, suggesting that BDE209 could accumulate slightly in muscle tissues. However, BDE209 was not detected in the blood for all treatments. Most congeners of De-BDEs were found in muscle and liver tissues, with the highest concentration in the liver. The main De-BDEs were nona-, octa-, hepta- and penta-De-BDEs. A total of seven MeO-BDE metabolites were observed among different fish tissues. Blood had the highest contribution of the MeO-BDE metabolites. Each MeO-BDE congener increased over the 28 days. These results in contrast to other studies suggested possible species-specific differences in metabolic abilities.展开更多
Background High dietary carbohydrates can spare protein in rainbow trout(Oncorhynchus mykiss)but may affect growth and health.Inulin,a prebiotic,could have nutritional and metabolic effects,along with anti-inflammator...Background High dietary carbohydrates can spare protein in rainbow trout(Oncorhynchus mykiss)but may affect growth and health.Inulin,a prebiotic,could have nutritional and metabolic effects,along with anti-inflammatory properties in teleosts,improving growth and welfare.We tested this hypothesis in rainbow trout by feeding them a 100%plant-based diet,which is a viable alternative to fishmeal and fish oil in aquaculture feeds.In a two-factor design,we examined the impact of inulin(2%)as well as the variation in the carbohydrates(CHO)/plant protein ratio on rainbow trout.We assessed the influence of these factors on zootechnical parameters,plasma metabolites,gut microbiota,production of short-chain fatty acids and lactic acid,as well as the expression of free-fatty acid receptor genes in the mid-intestine,intermediary liver metabolism,and immune markers in a 12-week feeding trial.Results The use of 2%inulin did not significantly change the fish intestinal microbiota,but interestingly,the high CHO/protein ratio group showed a change in intestinal microbiota and in particular the beta diversity,with 21 bacterial genera affected,including Ralstonia,Bacillus,and 11 lactic-acid producing bacteria.There were higher levels of butyric,and valeric acid in groups fed with high CHO/protein diet but not with inulin.The high CHO/protein group showed a decrease in the expression of pro-inflammatory cytokines(il1b,il8,and tnfa)in liver and a lower expression of the genes coding for tight-junction proteins in mid-intestine(tjp1a and tjp3).However,the 2%inulin did not modify the expression of plasma immune markers.Finally,inulin induced a negative effect on rainbow trout growth performance irrespective of the dietary carbohydrates.Conclusions With a 100%plant-based diet,inclusion of high levels of carbohydrates could be a promising way for fish nutrition in aquaculture through a protein sparing effect whereas the supplementation of 2%inulin does not appear to improve the use of CHO when combined with a 100%plant-based diet.展开更多
Body shape and metabolic rate can be important determinants of animal performance,yet often their effects on influential traits are evaluated in a non-integrated way.This creates an important gap because the integrati...Body shape and metabolic rate can be important determinants of animal performance,yet often their effects on influential traits are evaluated in a non-integrated way.This creates an important gap because the integration between shape and metabolism may be crucial to evaluate metabolic scaling theories.Here,we measured standard metabolic rate in 1-and 2-years old juvenile brown trout Salmo trutta,and used a geometric morphometrics approach to extricate the effects of ontogeny and size on the link between shape and metabolic scaling.We evidenced near-isometric ontogenetic scaling of metabolic rate with size,but also a biphasic pattern driven by a significant change in metabolic scaling,from positive to negative allometry.Moreover,the change in metabolic allometry parallels an ontogenetic change from elongate to deep-bodied shapes.This is consistent with the dynamic energy budget(DEB)and surface area(SA)theories,but not with the resource transport network theory which predicts increasing allometric exponents for trends towards more robust,three-dimensional bodies.In addition,we found a relationship between body shape and size independent metabolic rate,with a positive correlation between robustness and metabolic rate,which fits well within the view of Pace-of-Life Syndromes(POLS).Finally,our results align with previous studies that question the universality of metabolic scaling exponents and propose other mechanistic models explaining the diversity of metabolic scaling relationships or emphasizing the potential contribution of ecological factors.展开更多
This study examined the spatial and temporal characteristics of brook trout Salvelinus fontinalis and brown trout Salmo trutta redds in two sites from two creeks in the Black Hills of South Dakota, USA. Spawning began...This study examined the spatial and temporal characteristics of brook trout Salvelinus fontinalis and brown trout Salmo trutta redds in two sites from two creeks in the Black Hills of South Dakota, USA. Spawning began in both streams in early October and continued through mid-November. Significant spatial clustering was only observed on both Rapid Creek sites, where-as random redd development was observed in both of the sites on Box Elder Creek. Based on visual observations, brown trout redds were more abundant in Rapid Creek, where-as brook trout redds were more abundant in Box Elder Creek. Differences in redd clustering could be due to species-specific, geological, or hydrological differences between the展开更多
This study examined the effect of different salinities(0, 5, 10, 15, 20, 25 and 30) on the growth performance and energy budget of juveniles of two different ecotypes of Oncorhynchus mykiss, landlocked rainbow trout a...This study examined the effect of different salinities(0, 5, 10, 15, 20, 25 and 30) on the growth performance and energy budget of juveniles of two different ecotypes of Oncorhynchus mykiss, landlocked rainbow trout and anadromous steelhead trout. In the 42 d experiment, fish were cultured in three replicate tanks per salinity treatment(eight fish per tank). At the end of the experiment, the growth of rainbow and steelhead trouts was significantly higher at salinities of 5 and 10, respectively, than at all other salinities. The protein, lipid and energy content of both ecotypes declined with the increase of salinity. Based on their energy budgets, the percentage of energy consumed for growth by rainbow and steelhead trouts were significantly higher at salinities of 5(34.00% ±1.69%) and 10(43.76% ± 1.29%), respectively, than at all other salinities. The percentage of energy consumed for respiration by rainbow and steelhead trouts was lower at salinities of 5(54.90% ± 1.77%) and 10(46.73% ± 0.62%), respectively, than at all other salinities. Our results indicated that the salinity adaptation ability of juvenile steelhead trout was slightly better than that of juvenile rainbow trout, and salinities of 10 and 5, respectively, were most suitable for growth of these two fishes.展开更多
This study compared three surgical techniques to implant acoustic transmitters in rainbow trout (</span><i><span style="font-family:Verdana;">Oncorhynchus mykiss</span></i><s...This study compared three surgical techniques to implant acoustic transmitters in rainbow trout (</span><i><span style="font-family:Verdana;">Oncorhynchus mykiss</span></i><span style="font-family:Verdana;">): 1</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">)</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> acoustic transmitter insertion via a ventral incision closed with two sutures, 2</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">)</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> insertion via a ventral incision with no sutures, 3</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">)</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> insertion via a lateral incision with no sutures. A control group consisting of fish that were only anesthetized and handled was also included. Tag retention, wound healing, inflammation, growth, and survival were recorded over a 12</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">week period. Tag retention was significantly different among the treatments, at 100% in the unsutured ventral incision group, 89% in the lateral incision group, and 63% in the sutured ventral incision group. Surgical wounds in the unsutured treatment groups showed significantly less inflammation than the sutured treatment. Wound closure occurred significantly faster in the ventral incision groups compared to the lateral incision group. The results of this展开更多
Freshwater vertebrate and invertebrate prey species commonly rely on chemosensory information, including non-injury released disturbance cues, to assess local predation threats. We conducted laboratory studies to （1...Freshwater vertebrate and invertebrate prey species commonly rely on chemosensory information, including non-injury released disturbance cues, to assess local predation threats. We conducted laboratory studies to （1） determine if urea can function as a disturbance cue in juvenile convict cichlids and rainbow trout and （2） determine if the background level of urea influences the behavioral response to a subsequent pulse of urea （＇background noise＇ hypothesis）. In the first series of trials, juve- nile cichlids and trout were exposed to urea at varying concentrations （0 to 0.5 mg L-1 for cichlids and 0 to 1.0 mg L1 for trout）. Our results suggest that both cichilds and trout exhibited functionally similar responses to urea and conspecific disturbance cues and that increasing the concentration of urea results in an increase intensity of antipredator behaviour. In the second series of trials, we pre-exposed cichlids or trout to intermediate or high concentrations of urea （or a distilled water control） and then tested for the response to a second pulse of urea at at intermediate or high concentrations （versus a distilled water control）. Our results demon- strate that pre-exposure to urea reduces or eliminates the response to a second pulse of urea, supporting the background noise hy- pothesis. Together, our results suggest that pulses of urea, released by disturbed or stressed individuals, may function as an early warning signal in freshwater prey species展开更多
Radioimmunoassay,enzyme linked immunospot assay and enzyme immunoassay were used for the determinations of plasma steroid hormone's level,antibody producing cell's counting and IgM level in this study.The de...Radioimmunoassay,enzyme linked immunospot assay and enzyme immunoassay were used for the determinations of plasma steroid hormone's level,antibody producing cell's counting and IgM level in this study.The decreased number of antibody producing cells and low IgM levels were observed in sexual immature rainbow trout during the spawning season.These fish were reared under almost constant water temperature and natural photoperiod.Moreover,low IgM level was also observed in immature rainbow trout,which were reared under short photoperiod,and IgM level was not changed by treatment of testosterone.The results suggest that photoperoid may cause the changes in immune competence.It is possible that circadian rhythm accompanied with photoperiod may influence physiological function of fish,so that immune competence is changed.展开更多
Often,catch and release regulations are meant to maximize a fisheries potential to create trophy fish.I evaluated adult Brown Trout populations at five locations within Rapid Creek within Rapid City,SD over a two-year...Often,catch and release regulations are meant to maximize a fisheries potential to create trophy fish.I evaluated adult Brown Trout populations at five locations within Rapid Creek within Rapid City,SD over a two-year period.In each year,one of these locations was within a catch and release area,while two were outside.In 2012,density and biomass estimates were higher in a site located outside of the catch and release area.Additionally,size structure within the catch and release area was only significantly larger than one of the two sites outside of the regulation area.Mean relative weight values were inversely related to density estimates,with the lowest density sites having the highest mean relative weights.Similarly,a site outside of the catch and release area had the highest abundance and biomass estimates in 2013.The cumulative length distribution was significantly different between the site within the catch and release area and the two located outside.Relative weight was significantly higher in the catch and release area than the two sites outside.As population characteristics within the catch and release area were not consistently better than outside,it is more likely that factors such as habitat and density dependence are impacting the Brown Trout population more than the regulation itself.展开更多
Hatchery-reared fish are frequently adjusted (tempered) to the higher water temperatures present in the water bodies where they are to be stocked. This study was undertaken to determine the necessity of such tempering...Hatchery-reared fish are frequently adjusted (tempered) to the higher water temperatures present in the water bodies where they are to be stocked. This study was undertaken to determine the necessity of such tempering practices. <span><span style="font-family:Verdana;">This study used rainbow trout (</span><i><span style="font-family:Verdana;">Oncorhynchus mykiss</span></i><span style="font-family:Verdana;">) and brown trout</span></span><span style="font-family:Verdana;"> (</span><i><span style="font-family:Verdana;">Salmo trutta</span></i><span style="font-family:Verdana;">) reared at 11.2</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">°C. </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">The first two trials for each species were designed to simultaneously determine the upper incipient lethal temperature and 100% lethal temperature over a 14-day period. The third trial for each species evaluated the effects of an exaggerated 12-hour tempering regime on fish survival after placement in elevated water temperatures. After transfer from a water temperature of 11.2°C, no rainbow trout survived at 26°C, and only 50% survived at 25°C. No brown trout survived at 22°C and only 50% at 20°C. Survival of rainbow trout was not improved by the 12-hour tempering regime where water temperatures were slowly increased from 11.2°C to either 25°C or 26°C. Similarly, tempering did not improve brown trout survival at either 20°C or 22°C. These results suggest that tempering is not needed when hatchery-reared trout are reared and stocked at the water temperatures within the range of those used in this study.</span></span></span>展开更多
A novel sutureless surgical technique has been successfully used to implant acoustic transmitters in relatively large rainbow trout Oncorhynchus mykiss with a tag-to-body-ratio of 0.88%. This study examined the same t...A novel sutureless surgical technique has been successfully used to implant acoustic transmitters in relatively large rainbow trout Oncorhynchus mykiss with a tag-to-body-ratio of 0.88%. This study examined the same technique in smaller rainbow trout in two, 12-week trials comparing both sutured and sutureless surgical techniques. In the first trial using a tag-to-body-ratio of 1.9% ± 0.04%, tag retention was only 16.6% in fish without sutures, which was significantly lower than the 83.3% retention with sutured incisions. Similarly, in the second trial with a tag-to-body-ratio of 3.2% ± 0.03%, tag retention was 55.5% without sutures, which was significantly lower than the 90.0% retention using sutures. Mortality was not significantly different between treatments in either trial. The results of this study indicate that sutures must be used during surgeries to implant acoustic transmitters in relatively smaller fish with tag-to-body-ratios at or above 1.9%.展开更多
Decabromodiphenyl ether(BDE209) is poorly absorbed by mammals,and little information is available on the toxicokinetics of BDE209 and its metabolites in fish.In the present study,rainbow trout(Oncorhynchus mykiss) wer...Decabromodiphenyl ether(BDE209) is poorly absorbed by mammals,and little information is available on the toxicokinetics of BDE209 and its metabolites in fish.In the present study,rainbow trout(Oncorhynchus mykiss) were administered to 100 ng/g and 500 ng/g body wet weight of BDE209 via a single intraperitoneal injection and parent BDE209 and its metabolites were sequentially monitored for 28 days.The results showed that toxicokinetic profiles of BDE209 could be described by the one-compartment model.In the higher dose group(500 ng/g wet weight),the calculated half-life(t1/2) and elimination rate(ke) were 17.7 d and 0.039/d in the liver,and 100.3 d and 0.007/d in the muscle,respectively.Three major methoxylated brominated diphenyl ethers(MeO-BDEs) were detected with 2,2',4,4'-tetrabromo-5-methoxydiphenyl ether(5-MeO-BDE47) being detected in all tissue samples.There was no significant temporal change of 5-MeO-BDE47 concentration in the muscle,whereas an exponential increase was observed in the liver.Therefore,the metabolism rate of BDE209 depended on the administered dose.BDE209 was hardly accumulated in the muscle of rainbow trout,while the liver was a primary metabolic organ.MeO-BDEs were formed via metabolism of BDE209,which probably played a significant role in fish toxicology as a potential indicator.展开更多
The implantation of acoustic transmitters into the peritoneal cavity of fish is typically performed by experienced surgeons. This study compared the effectiveness of an experienced and inexperienced surgeon performing...The implantation of acoustic transmitters into the peritoneal cavity of fish is typically performed by experienced surgeons. This study compared the effectiveness of an experienced and inexperienced surgeon performing two different types of transmitter insertion techniques on rainbow trout (<i>Oncorhynchus</i> <i>mykiss</i>). The methods used were either a traditional sutured ventral incision or a novel unsutured lateral incision. There was no significant difference in surgical duration, tag retention, or fish survival between the experienced and na<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">ï</span>ve surgeon. The time to complete surgical wound closure was not significantly different between the fish operated on by an experienced or na<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">ï</span>ve surgeon, and surgeon experience had no significant effect on the duration of inflammation. However, there were significant differences between the two surgical techniques, regardless of surgeon experience. The ventral incision with sutures method took approximately three times longer to complete than the lateral incision-only method. However, complete wound closure was significantly faster in the sutured ventral incision treatment compared to the unsutured lateral treatment. Post-surgery inflammation was over seven times longer in the fish with sutures compared to those only receiving a lateral incision. Tag retention was not significantly different between the two surgical methods. The results of this study indicate that the unsutured lateral surgical technique used in this experiment can be completed with minimal training and surgical experience in contrast to the standard technique requiring su<span>tures. These results also provide additional support to the use of sutureless</span> surgical techniques for acoustic transmitter implantation.展开更多
基金Financial support was provided by 11th 5-year National Key Technologies R & D Program Project No.2006BAD12B06,2006BAD12B08
文摘Effects of dietary supplementation of chitosan-oligosaccharides （COS） on the growth performance, immune response, stress resistance, and disease resistance of juvenile rainbow trout Oncorhynchus mykiss were studied. Four experimental diets containing 0, 20, 40, or 60 mg/kg COS （COSO, COS20, COS40, and COS60, respectively） were fed to juvenile rainbow trout （initial weight = 5.2 ± 0.3 g） for 8 weeks. By the end of the feeding trial, representative groups of fish from each dietary treatment were challenged with stressor （30 see air exposure） and pathogen exposure （intraperitoneal injection with Aeromonas hydrophila ）. Results showed that supplementation of COS in diets did not affect production performance and body composition of rainbow trout. However, fish fed the COS40 diet demonstrated improved phagocytic activities, respiratory burst activities and decreased serum cortisol level. Additionally, survival following A. hydrophila challenge was significant higher among fish fed the COS-supplemented feeds, although there was no difference based on the level of supplementation. The present study suggests that COS can be used as an immuno-stimulant in rainbow trout feeds
文摘The inclusion of PepSoyGen (PSG), a commercially-available fermented soybean meal product, was evaluated with juvenile rainbow trout, Oncorhynchus mykiss in an initial 70-day feeding trial, with a supplemental trial involving a subset of the experimental diets continuing for an additional 40 d. Six diets containing 0%, 10%, 20%, 30%, 40%, or 50% PSG, with the PSG directly replacing fish meal, were used in the first trial. There were no significant differences in weight gain or feed conversion ratio between the fish meal-based control diet and diets containing up to 30% PSG. However, weight gain was significantly reduced and feed conversion ratio significantly increased with the 40% and 50% PSG diets. No health assessment differences were observed in fish receiving any of the diets, and no evidence of gross gut inflammation was evident. There were no significant differences in weight gain or feed conversion ratio among the four dietary treatments ranging from 0% to 30% PSG which were fed for an additional 40 d after the initial 70-d trial (110 days total). Based on these results, juvenile rainbow trout diets can contain up to 30% PSG without any loss of rearing performance, thereby replacing at least 60% of the fish meal.
基金This research was partially funded by AGER,Network Foundation,Project Fine Feed for Fish(4F)Rif.No.2016-01-01This work was also co-funded by the EU Horizon 2020 AquaIMPACT(Genomic and nutritional innovations for genetically superior farmed fish to improve efficiency in European aquaculture),number:818367.
文摘Background:Aquaculture must continue to reduce dependence on fishmeal(FM)and fishoil in feeds to ensure sustainable sector growth.Therefore,the use of novel aquaculture feed ingredients is growing.In this regard,insects can represent a new world of sustainable and protein-rich ingredients for farmed fish feeds.Accordingly,we investigated the effects of full replacement of FM with Tenebrio molitor(TM)larvae meal in the diet of rainbow trout(Oncorhynchus mykiss)on fish gut and skin microbiota.Methods:A feeding trial was conducted with 126 trout of about 80 g mean initial weight that were fed for 22 weeks with two isonitrogenous,isolipidic,and isoenergetic extruded experimental diets.Partially defatted TM meal was included in one of the diets to replace 100%(TM 100)of FM,whereas the other diet(TM 0)was without TM.To analyse the microbial communities,the Illumina MiSeq platform for sequencing of 16S rRNA gene and Qiime pipeline were used to identify bacteria in the gut and skin mucosa,and in the diets.Results:The data showed no major effects of full FM substitution with TM meal on bacterial species richness and diversity in both,gut mucosa-and skin mucus-associated microbiome.Skin microbiome was dominated by phylum Proteobacteria and especially by Gammaproteobacteria class that constituted approximately half of the bacterial taxa found.The two dietary fish groups did not display distinctive features,except for a decrease in the relative abundance of Deefgea genus(family Neisseriaceae)in trout fed with insect meal.The metagenomic analysis of the gut mucosa indicated that Tenericutes was the most abundant phylum,regardless of the diet.Specifically,within this phylum,the Mollicutes,mainly represented by Mycoplasmataceae family,were the dominant class.However,we observed only a weak dietary modulation of intestinal bacterial communities.The only changes due to full FM replacement with TM meal were a decreased number of Proteobacteria and a reduced number of taxa assigned to Ruminococcaceae and Neisseriaceae families.Conc
基金supported by the National Natural Science Foundation of China(42177254)Science and Technology Planning Project of Guangdong Province(2020B1212030008)。
文摘N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine quinone(6PPDQ)has attracted significant attention due to its highly acute lethality to sensitive salmonids.However,studies investigating the mechanisms underlying its acute toxicity have been lacking.In this work,we demonstrated the sensitivity of rainbow trout to 6PPDQ-induced mortality.Moribund trout exhibited significantly higher brain concentrations of 6PPDQ compared to surviving trout.In an in vitro model using human brain microvascular endothelial cells,6PPDQ can penetrate the blood–brain barrier and enhance blood–brain barrier permeability without compromising cell viability.The time spent in the top of the tank increased with rising6PPDQ concentrations,as indicated by locomotion behavior tests.Furthermore,6PPDQ influenced neurotransmitter levels and m RNA expression of neurotransmission-related genes in the brain and exhibited strong binding affinity to target neurotransmission-related proteins using computational simulations.The integrated biomarker response value associated with neurotoxicity showed a positive linear correlation with trout mortality.These findings significantly contribute to filling the knowledge gap between neurological impairments and apical outcomes,including behavioral effects and mortality,induced by6PPDQ.
文摘Juvenile rainbow trout Oncorhynchus mykiss were subjected to one of four treatments in a two-by-two experimental design: 1) fed at a density of 1.8 g/m<sup>3</sup>, 2) Fasted at 1.8 g/m<sup>3</sup>, 3) fed at 30.1 g/m<sup>3</sup>, and 4) fasted at 30.1 g/m<sup>3</sup>. Blood glucose and hematocrit were measured at 4, 6, 48, 168, and 336 hours after placement in one of the two rearing densities, with relative fin lengths and organosomatic indices recorded at 336 hours. Glucose levels over time were not significantly different among the density and feeding treatments. Hematocrit levels over time were also not significantly different. Total lengths, weight, hepatosomatic index, viscerosomatic index, and any of the relative fin lengths were not significantly different between the high and low densities. However, the hepatosomatic index was significantly greater in the fed fish compared to those fasted. The splenosomatic index was significantly greater in the higher density treatment. These results likely indicate no short-term stress response to the higher rearing density used in this short-term experiment and no interaction between starvation and density-related stressors.
基金supported by the National Basic Research Program (973) of China (No. 2009CB421605)the National Natural Science Foundation of China (No.20877089,20737003)
文摘Decabromodiphenyl ether （BDE209） is the primary component in a commonly used flame retardant. Previous studies had proved that BDE209 itself was not toxic, while its metabolites including debrominated diphenyl ethers （De-BDEs） and methoxylated brominated diphenyl ethers （MeO-BDEs） posed a potential threat to organisms. Many studies had indicated that BDE209 could metabolize quickly in mammals, but lacking in the basic data about the metabolism of BDE209 in fish. In the present study, two replicate treatment groups of rainbow trout （Oncorhynchus rnykiss） were exposed to BDE209 via a single intraperitoneal injection approximately 100 and 500 ng/g, respectively. Muscle, liver and blood samples were collected to analyze the specific metabolites on day 1 and day 28 post injection. The highest concentration of BDE209 was detected in muscle tissues, from 796.1 ng/g wet weight （day 1） to 687.1 ng/g wet weight （day 28） in high dose group, suggesting that BDE209 could accumulate slightly in muscle tissues. However, BDE209 was not detected in the blood for all treatments. Most congeners of De-BDEs were found in muscle and liver tissues, with the highest concentration in the liver. The main De-BDEs were nona-, octa-, hepta- and penta-De-BDEs. A total of seven MeO-BDE metabolites were observed among different fish tissues. Blood had the highest contribution of the MeO-BDE metabolites. Each MeO-BDE congener increased over the 28 days. These results in contrast to other studies suggested possible species-specific differences in metabolic abilities.
基金funded by the CD40 (Departmental Council of the Landes)the “Universitéde Pau et Pays de l’Adour “(UPPA)
文摘Background High dietary carbohydrates can spare protein in rainbow trout(Oncorhynchus mykiss)but may affect growth and health.Inulin,a prebiotic,could have nutritional and metabolic effects,along with anti-inflammatory properties in teleosts,improving growth and welfare.We tested this hypothesis in rainbow trout by feeding them a 100%plant-based diet,which is a viable alternative to fishmeal and fish oil in aquaculture feeds.In a two-factor design,we examined the impact of inulin(2%)as well as the variation in the carbohydrates(CHO)/plant protein ratio on rainbow trout.We assessed the influence of these factors on zootechnical parameters,plasma metabolites,gut microbiota,production of short-chain fatty acids and lactic acid,as well as the expression of free-fatty acid receptor genes in the mid-intestine,intermediary liver metabolism,and immune markers in a 12-week feeding trial.Results The use of 2%inulin did not significantly change the fish intestinal microbiota,but interestingly,the high CHO/protein ratio group showed a change in intestinal microbiota and in particular the beta diversity,with 21 bacterial genera affected,including Ralstonia,Bacillus,and 11 lactic-acid producing bacteria.There were higher levels of butyric,and valeric acid in groups fed with high CHO/protein diet but not with inulin.The high CHO/protein group showed a decrease in the expression of pro-inflammatory cytokines(il1b,il8,and tnfa)in liver and a lower expression of the genes coding for tight-junction proteins in mid-intestine(tjp1a and tjp3).However,the 2%inulin did not modify the expression of plasma immune markers.Finally,inulin induced a negative effect on rainbow trout growth performance irrespective of the dietary carbohydrates.Conclusions With a 100%plant-based diet,inclusion of high levels of carbohydrates could be a promising way for fish nutrition in aquaculture through a protein sparing effect whereas the supplementation of 2%inulin does not appear to improve the use of CHO when combined with a 100%plant-based diet.
基金This work was supported by the Principality of Asturias(grant no.CN-07-164)the Spanish Government(grants no.MEC-CGL2004-03239/BOS and MMA/86-2003-1)FICYT(predoctoral fellowship BPO4-147 to J.R.S.G.)。
文摘Body shape and metabolic rate can be important determinants of animal performance,yet often their effects on influential traits are evaluated in a non-integrated way.This creates an important gap because the integration between shape and metabolism may be crucial to evaluate metabolic scaling theories.Here,we measured standard metabolic rate in 1-and 2-years old juvenile brown trout Salmo trutta,and used a geometric morphometrics approach to extricate the effects of ontogeny and size on the link between shape and metabolic scaling.We evidenced near-isometric ontogenetic scaling of metabolic rate with size,but also a biphasic pattern driven by a significant change in metabolic scaling,from positive to negative allometry.Moreover,the change in metabolic allometry parallels an ontogenetic change from elongate to deep-bodied shapes.This is consistent with the dynamic energy budget(DEB)and surface area(SA)theories,but not with the resource transport network theory which predicts increasing allometric exponents for trends towards more robust,three-dimensional bodies.In addition,we found a relationship between body shape and size independent metabolic rate,with a positive correlation between robustness and metabolic rate,which fits well within the view of Pace-of-Life Syndromes(POLS).Finally,our results align with previous studies that question the universality of metabolic scaling exponents and propose other mechanistic models explaining the diversity of metabolic scaling relationships or emphasizing the potential contribution of ecological factors.
文摘This study examined the spatial and temporal characteristics of brook trout Salvelinus fontinalis and brown trout Salmo trutta redds in two sites from two creeks in the Black Hills of South Dakota, USA. Spawning began in both streams in early October and continued through mid-November. Significant spatial clustering was only observed on both Rapid Creek sites, where-as random redd development was observed in both of the sites on Box Elder Creek. Based on visual observations, brown trout redds were more abundant in Rapid Creek, where-as brook trout redds were more abundant in Box Elder Creek. Differences in redd clustering could be due to species-specific, geological, or hydrological differences between the
基金jointly funded by the National Natural Science Foundation of China (Nos. 31702364 and 3157 2634)the Primary Research and Development Program of Shandong Province (Nos. 2016CYJS04A01 and 2017CXGC0106)
文摘This study examined the effect of different salinities(0, 5, 10, 15, 20, 25 and 30) on the growth performance and energy budget of juveniles of two different ecotypes of Oncorhynchus mykiss, landlocked rainbow trout and anadromous steelhead trout. In the 42 d experiment, fish were cultured in three replicate tanks per salinity treatment(eight fish per tank). At the end of the experiment, the growth of rainbow and steelhead trouts was significantly higher at salinities of 5 and 10, respectively, than at all other salinities. The protein, lipid and energy content of both ecotypes declined with the increase of salinity. Based on their energy budgets, the percentage of energy consumed for growth by rainbow and steelhead trouts were significantly higher at salinities of 5(34.00% ±1.69%) and 10(43.76% ± 1.29%), respectively, than at all other salinities. The percentage of energy consumed for respiration by rainbow and steelhead trouts was lower at salinities of 5(54.90% ± 1.77%) and 10(46.73% ± 0.62%), respectively, than at all other salinities. Our results indicated that the salinity adaptation ability of juvenile steelhead trout was slightly better than that of juvenile rainbow trout, and salinities of 10 and 5, respectively, were most suitable for growth of these two fishes.
文摘This study compared three surgical techniques to implant acoustic transmitters in rainbow trout (</span><i><span style="font-family:Verdana;">Oncorhynchus mykiss</span></i><span style="font-family:Verdana;">): 1</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">)</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> acoustic transmitter insertion via a ventral incision closed with two sutures, 2</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">)</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> insertion via a ventral incision with no sutures, 3</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">)</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> insertion via a lateral incision with no sutures. A control group consisting of fish that were only anesthetized and handled was also included. Tag retention, wound healing, inflammation, growth, and survival were recorded over a 12</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">week period. Tag retention was significantly different among the treatments, at 100% in the unsutured ventral incision group, 89% in the lateral incision group, and 63% in the sutured ventral incision group. Surgical wounds in the unsutured treatment groups showed significantly less inflammation than the sutured treatment. Wound closure occurred significantly faster in the ventral incision groups compared to the lateral incision group. The results of this
文摘Freshwater vertebrate and invertebrate prey species commonly rely on chemosensory information, including non-injury released disturbance cues, to assess local predation threats. We conducted laboratory studies to （1） determine if urea can function as a disturbance cue in juvenile convict cichlids and rainbow trout and （2） determine if the background level of urea influences the behavioral response to a subsequent pulse of urea （＇background noise＇ hypothesis）. In the first series of trials, juve- nile cichlids and trout were exposed to urea at varying concentrations （0 to 0.5 mg L-1 for cichlids and 0 to 1.0 mg L1 for trout）. Our results suggest that both cichilds and trout exhibited functionally similar responses to urea and conspecific disturbance cues and that increasing the concentration of urea results in an increase intensity of antipredator behaviour. In the second series of trials, we pre-exposed cichlids or trout to intermediate or high concentrations of urea （or a distilled water control） and then tested for the response to a second pulse of urea at at intermediate or high concentrations （versus a distilled water control）. Our results demon- strate that pre-exposure to urea reduces or eliminates the response to a second pulse of urea, supporting the background noise hy- pothesis. Together, our results suggest that pulses of urea, released by disturbed or stressed individuals, may function as an early warning signal in freshwater prey species
文摘Radioimmunoassay,enzyme linked immunospot assay and enzyme immunoassay were used for the determinations of plasma steroid hormone's level,antibody producing cell's counting and IgM level in this study.The decreased number of antibody producing cells and low IgM levels were observed in sexual immature rainbow trout during the spawning season.These fish were reared under almost constant water temperature and natural photoperiod.Moreover,low IgM level was also observed in immature rainbow trout,which were reared under short photoperiod,and IgM level was not changed by treatment of testosterone.The results suggest that photoperoid may cause the changes in immune competence.It is possible that circadian rhythm accompanied with photoperiod may influence physiological function of fish,so that immune competence is changed.
文摘Often,catch and release regulations are meant to maximize a fisheries potential to create trophy fish.I evaluated adult Brown Trout populations at five locations within Rapid Creek within Rapid City,SD over a two-year period.In each year,one of these locations was within a catch and release area,while two were outside.In 2012,density and biomass estimates were higher in a site located outside of the catch and release area.Additionally,size structure within the catch and release area was only significantly larger than one of the two sites outside of the regulation area.Mean relative weight values were inversely related to density estimates,with the lowest density sites having the highest mean relative weights.Similarly,a site outside of the catch and release area had the highest abundance and biomass estimates in 2013.The cumulative length distribution was significantly different between the site within the catch and release area and the two located outside.Relative weight was significantly higher in the catch and release area than the two sites outside.As population characteristics within the catch and release area were not consistently better than outside,it is more likely that factors such as habitat and density dependence are impacting the Brown Trout population more than the regulation itself.
文摘Hatchery-reared fish are frequently adjusted (tempered) to the higher water temperatures present in the water bodies where they are to be stocked. This study was undertaken to determine the necessity of such tempering practices. <span><span style="font-family:Verdana;">This study used rainbow trout (</span><i><span style="font-family:Verdana;">Oncorhynchus mykiss</span></i><span style="font-family:Verdana;">) and brown trout</span></span><span style="font-family:Verdana;"> (</span><i><span style="font-family:Verdana;">Salmo trutta</span></i><span style="font-family:Verdana;">) reared at 11.2</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">°C. </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">The first two trials for each species were designed to simultaneously determine the upper incipient lethal temperature and 100% lethal temperature over a 14-day period. The third trial for each species evaluated the effects of an exaggerated 12-hour tempering regime on fish survival after placement in elevated water temperatures. After transfer from a water temperature of 11.2°C, no rainbow trout survived at 26°C, and only 50% survived at 25°C. No brown trout survived at 22°C and only 50% at 20°C. Survival of rainbow trout was not improved by the 12-hour tempering regime where water temperatures were slowly increased from 11.2°C to either 25°C or 26°C. Similarly, tempering did not improve brown trout survival at either 20°C or 22°C. These results suggest that tempering is not needed when hatchery-reared trout are reared and stocked at the water temperatures within the range of those used in this study.</span></span></span>
文摘A novel sutureless surgical technique has been successfully used to implant acoustic transmitters in relatively large rainbow trout Oncorhynchus mykiss with a tag-to-body-ratio of 0.88%. This study examined the same technique in smaller rainbow trout in two, 12-week trials comparing both sutured and sutureless surgical techniques. In the first trial using a tag-to-body-ratio of 1.9% ± 0.04%, tag retention was only 16.6% in fish without sutures, which was significantly lower than the 83.3% retention with sutured incisions. Similarly, in the second trial with a tag-to-body-ratio of 3.2% ± 0.03%, tag retention was 55.5% without sutures, which was significantly lower than the 90.0% retention using sutures. Mortality was not significantly different between treatments in either trial. The results of this study indicate that sutures must be used during surgeries to implant acoustic transmitters in relatively smaller fish with tag-to-body-ratios at or above 1.9%.
基金supported by the National Basic Research Program of China (2009CB421605)the National Natural Science Foundation of China (20737003 & 20877089)
文摘Decabromodiphenyl ether(BDE209) is poorly absorbed by mammals,and little information is available on the toxicokinetics of BDE209 and its metabolites in fish.In the present study,rainbow trout(Oncorhynchus mykiss) were administered to 100 ng/g and 500 ng/g body wet weight of BDE209 via a single intraperitoneal injection and parent BDE209 and its metabolites were sequentially monitored for 28 days.The results showed that toxicokinetic profiles of BDE209 could be described by the one-compartment model.In the higher dose group(500 ng/g wet weight),the calculated half-life(t1/2) and elimination rate(ke) were 17.7 d and 0.039/d in the liver,and 100.3 d and 0.007/d in the muscle,respectively.Three major methoxylated brominated diphenyl ethers(MeO-BDEs) were detected with 2,2',4,4'-tetrabromo-5-methoxydiphenyl ether(5-MeO-BDE47) being detected in all tissue samples.There was no significant temporal change of 5-MeO-BDE47 concentration in the muscle,whereas an exponential increase was observed in the liver.Therefore,the metabolism rate of BDE209 depended on the administered dose.BDE209 was hardly accumulated in the muscle of rainbow trout,while the liver was a primary metabolic organ.MeO-BDEs were formed via metabolism of BDE209,which probably played a significant role in fish toxicology as a potential indicator.
文摘The implantation of acoustic transmitters into the peritoneal cavity of fish is typically performed by experienced surgeons. This study compared the effectiveness of an experienced and inexperienced surgeon performing two different types of transmitter insertion techniques on rainbow trout (<i>Oncorhynchus</i> <i>mykiss</i>). The methods used were either a traditional sutured ventral incision or a novel unsutured lateral incision. There was no significant difference in surgical duration, tag retention, or fish survival between the experienced and na<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">ï</span>ve surgeon. The time to complete surgical wound closure was not significantly different between the fish operated on by an experienced or na<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">ï</span>ve surgeon, and surgeon experience had no significant effect on the duration of inflammation. However, there were significant differences between the two surgical techniques, regardless of surgeon experience. The ventral incision with sutures method took approximately three times longer to complete than the lateral incision-only method. However, complete wound closure was significantly faster in the sutured ventral incision treatment compared to the unsutured lateral treatment. Post-surgery inflammation was over seven times longer in the fish with sutures compared to those only receiving a lateral incision. Tag retention was not significantly different between the two surgical methods. The results of this study indicate that the unsutured lateral surgical technique used in this experiment can be completed with minimal training and surgical experience in contrast to the standard technique requiring su<span>tures. These results also provide additional support to the use of sutureless</span> surgical techniques for acoustic transmitter implantation.
