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Per Gunnar Fjelldal - One of the best experts on this subject based on the ideXlab platform.
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water temperature and oxygen the effect of Triploidy on performance and metabolism in farmed atlantic salmon salmo salar l post smolts
Aquaculture, 2017Co-Authors: Florian Sambraus, Tom Hansen, Rolf Erik Olsen, Thomas Torgersen, Mette Remen, Per Gunnar FjelldalAbstract:Abstract The use of sterile triploids in Atlantic salmon aquaculture would mitigate the environmental risks associated with introgressive hybridization between escaped farmed and wild Atlantic salmon. However, production of farmed triploid salmon is limited due to reports of poorer growth and higher mortality when compared to diploids, in particular under sub-optimal environmental conditions. To address these concerns, we monitored triploid and diploid Atlantic salmon post-smolts at temperatures between 3 and 18 °C and 100% oxygen saturation (O2 sat), and additional periods of 60% O2 sat (hypoxia) at 6 or 18 °C, respectively. Feed intake and oxygen consumption rate were monitored throughout the experimental period. Muscle and blood samples were collected at 100 and 60% O2 sat at 6 and 18 °C for analysis of white muscle energy phosphates (creatine phosphate, adenosine triphosphate) and carbohydrate fuels (glucose, glycogen) as well as blood clinical chemistry (whole blood: hematocrit; plasma: Na+, K+, Cl−, glucose, lactate, pH, triacylglycerol). Mortality was similar between ploidies, but higher in triploids compared to diploids during reduced O2 sat at 18 °C. Compared to diploids, triploids had higher feed intake (% biomass) at ≤ 9 °C, but lower feed intake at ≥ 15 °C. Feed intake peaked at 12 and 15 °C for triploids and diploids, respectively. Triploids progressively reduced feed intake with increasing temperature after peak feeding, indicating reduced scope for specific dynamic action with increasing water temperature. During hypoxia, triploids had lower feed intake than diploids at 6 and 18 °C. The difference in feed intake was not associated with any ploidy effect on body weight gain or feed conversion ratio, but triploids had greater body length growth compared to diploids. At ≥ 15 °C triploids consumed less oxygen than diploids. In the white musculature, the only observed difference between ploidies was a lower level of glycogen in triploids compared to diploids at 18 °C and 100% O2 sat. In the blood plasma, the concentration of ions was lower and glucose level higher in triploids compared to diploids at 18 °C and 60% O2 sat. The results of this study indicate that triploid Atlantic salmon post-smolts can substitute diploids, but are less tolerant to high seawater temperature and low O2 sat. For sea-cage farming of triploid salmon post-smolts, this would favour production areas with maximum temperatures of 15 °C and sufficient oxygen. Statement of Relevance This study demonstrates that triploid Atlantic salmon post-smolts have lower temperature optima for feeding and growth than diploids, a similar physiological response to high temperatures, but higher mortality under suboptimal conditions. Consequently triploid Atlantic salmon post-smolts may be well suited for commercial farming in geographical regions with moderate water temperatures in the summer and autumn months.
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Ploidy elicits a whole-genome dosage effect: growth of triploid Atlantic salmon is linked to the genetic origin of the second maternal chromosome set
'Springer Science and Business Media LLC', 2017Co-Authors: A. C. Harvey, Per Gunnar Fjelldal, M. F. Solberg, T. Hansen, K. A. GloverAbstract:Abstract Background The Atlantic salmon aquaculture industry is investigating the feasibility of using sterile triploids to mitigate genetic interactions with wild conspecifics, however, studies investigating diploid and triploid performance often show contrasting results. Studies have identified dosage and dosage-compensation effects for gene expression between triploid and diploid salmonids, but no study has investigated how ploidy and parent-origin effects interact on a polygenic trait in divergent lines of Atlantic salmon (i.e. slow growing wild versus fast growing domesticated phenotype). This study utilised two experiments relating to the freshwater growth of diploid and triploid groups of pure wild (0% domesticated genome), pure domesticated (100% domesticated genome), and F1 reciprocal hybrid (33%, 50% or 66% domesticated genome) salmon where Triploidy was either artificially induced (experiment 1) or naturally developed/spontaneous (experiment 2). Results In both experiments, reciprocal hybrid growth was influenced by the dosage effect of the second maternal chromosome, with growth increasing as ploidy level increased in individuals with a domesticated dam (from 50% to 66% domesticated genome), and the inverse in individuals with a wild dam (from 50% to 33% domesticated genome). Conclusions We demonstrate that the combined effect of ploidy and parent-origin on growth, a polygenic trait, is regulated in an additive pattern. Therefore, in order to maximise growth potential, the aquaculture industry should consider placing more emphasis on the breeding value of the dam than the sire when producing triploid families for commercial production
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effect of water oxygen level on performance of diploid and triploid atlantic salmon post smolts reared at high temperature
Aquaculture, 2015Co-Authors: Tom Hansen, Rolf Erik Olsen, Lars Helge Stien, Frode Oppedal, Thomas Torgersen, O Breck, Mette Remen, Tone Vagseth, Per Gunnar FjelldalAbstract:Abstract Sterilization by triploid induction prevents interbreeding between escaped farmed salmon and wild stocks, but reduced performance of triploids at high seawater temperatures has been reported. As high temperature may be followed by limited oxygen (O 2 ) supply in net cages, this study compared the effect of reducing O 2 from 100% to 70% of air saturation (termed hypoxia) on parameters of production performance (feed intake, growth, feed conversion ratio, mortality), and physiological status (plasma K + , Cl − , Na + , osmolality, glucose, creatinine (Cr), bilirubin, triacylglycerol (TAG) and alkaline phosphatase (ALP) concentrations) in triploid versus diploid Atlantic salmon kept at high seawater temperature (19 °C). Two triplicate groups of diploid and two triplicate groups of triploid Atlantic salmon post-smolts were acclimated to 10 °C and 100% O 2 before experiment start up. During the experiment, temperature was maintained at 10 °C for 10 days, increased to 19 °C over 9 days and kept stable at 19 °C until the experiment ended (day 51). From day 22 to 51, the O 2 level was reduced from 100% O 2 to 70% O 2 in one diploid and one triploid group. The abbreviated group names are 2N100, 2N70, 3N100 and 3N70. Triploidy led to reductions of feed intake and growth, and this effect was amplified by reducing O 2 from 100% to 70% O 2 . Analyses from blood samples drawn on day 51 show that plasma levels of Cl − , TAG, ALP and bilirubin were lowered in triploids in general, and that plasma Cr levels trebled and plasma K + levels dropped in triploids subjected to 70% O 2 for 29 days. Mortality was also significantly higher in the 3N70 group. According to these effects, the following order of production performance is suggested at high seawater temperature (best to worst): 2N100 > 2N70 ≥ 3N100 > 3N70. An interesting difference in the behavior between diploid and triploid fish was observed during the experiment: triploids generally moved against the tank water current, ram ventilating, as opposed to diploids, which displayed normal gill ventilation and were in part moving along with the current. The inability of triploid Atlantic salmon to withstand high temperature in combination with moderate hypoxia could set limitations to the geographical distribution of triploid salmon farming.
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the effect of Triploidy on vaccine side effects in atlantic salmon
Aquaculture, 2014Co-Authors: Thomas W K Fraser, Tom Hansen, Kevin A Glover, Ian Mayer, Jon Egil Skjaeraasen, Florian Sambraus, Per Gunnar FjelldalAbstract:Abstract Vaccination against bacterial diseases is an important aspect of commercial salmon production, but is known to have a number of unwanted side-effects including reduced growth, abdominal adhesions, and vertebral deformities. Our study objective was to compare these side-effects between diploid and sterile triploid salmon, the use of which would prevent genetic interactions between escaped farmed and wild salmon. A full factorial cross of vaccinated and unvaccinated, diploid and triploid, yearling (1 +) and under-yearling (0 +) mixed sex salmon were reared in triplicate in freshwater before common rearing in sea cages for 12–15 months. To further examine how ploidy may influence welfare with respect to vertebral deformities, a set of wild caught salmon were examined. Unvaccinated fish were larger (9% at termination) than vaccinated fish, but there was no effect of vaccination on skeletal deformities. In general, triploids grew as well or better in freshwater, but poorer in seawater compared to diploids, resulting in diploids being 12% larger than triploids at termination irrespective of smolt regime. In addition, triploids had a higher prevalence of fish with a least one deformed vertebra in 1 + smolts compared to diploids (34 vs 8%, respectively). However, vertebral compressions and fusions were observed in both ploidy, but were not apparent in the wild caught adult salmon control fish. Ploidy effects on the response to vaccination were limited to triploids having significantly higher vaccine-induced abdominal adhesion scores in 0 + smolts compared to diploids. Triploidy also prevented males becoming larger than females in vaccinated 0 + smolts in contrast to all other ploidy, vaccination, smolt regime combinations where males became the largest (8–12% at termination). Finally, notable levels of sexual maturation occurred in the male 0 + smolts, but fewer triploids matured as post-smolts or grilse in comparison to diploids. Based on our results, for best welfare practices the timing of vaccination may need to be altered when producing 0 + triploid smolts.
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vertebral deformities in triploid atlantic salmon salmo salar l underyearling smolts
Aquaculture, 2010Co-Authors: Per Gunnar Fjelldal, Tom HansenAbstract:Abstract This study investigated the prevalence of vertebral deformities in triploid and diploid Atlantic salmon smolts. Four full-sibling families were either subjected to hydrostatic pressure (655 bar, 6.25 min, 8 °C) (triploid) 37 min post-fertilization, or were maintained as untreated controls (diploid), and then reared to the smolt stage. Some 800 fish (100 per ploidy/family group) were palpated for vertebral deformities, and 480 (60 per ploidy/family group) of these were selected at random for radiography and evaluation for vertebral deformities. There was a significantly higher prevalence of triploid individuals classified as spinally deformed during palpation (triploids; 1–3%, diploids; 0–1%), and of individuals with one or more deformed vertebrae on radiographs (triploids; 30–35%, diploids; 8–13%). The trunk region (V9-30) of the vertebral column was the predominant location for deformities in triploids, with vertebra number 24 being the most often affected. Of the triploids, 7.6% had a malformation in this particular vertebra, which is located beneath the dorsal fin.
Tillmann J Benfey - One of the best experts on this subject based on the ideXlab platform.
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Triploidy affects postprandial ammonia excretion but not specific dynamic action in 1 brook charr salvelinus fontinalis
Aquaculture, 2021Co-Authors: Nicole J Daigle, Charles F D Sacobie, Christine E Verhille, Tillmann J BenfeyAbstract:Abstract The use of sterile triploids in aquaculture is currently limited because of reduced performance in situations of aerobic stress such as high temperature, hypoxia, and exhaustive exercise. Many studies have therefore attempted to find underlying metabolic differences between triploids and their diploid counterparts to improve triploid rearing protocols. This study investigated the effects of Triploidy on postprandial metabolism (and therefore also pre-feeding standard metabolic rate; SMR) in 1+ (193 ± 5 g; mean ± SE) diploid and triploid brook charr, Salvelinus fontinalis. Oxygen uptake and total ammonia nitrogen (TAN) excretion were measured at 14–15 °C for previously fasted (for eight days) fish from 48 h before to 48 h after being sham fed or fed a single ration of 0.4% of their body mass. While there were no ploidy-related differences in SMR or any of the measured SDA parameters, triploids had significantly higher net TAN excretion (by 36%) than diploids. Such a difference in protein metabolism could affect triploid growth and survival when simultaneously faced with suboptimal conditions, though further studies are warranted.
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the effect of dietary energy level on growth and nutrient utilization by juvenile diploid and triploid brook charr salvelinus fontinalis
Aquaculture Nutrition, 2016Co-Authors: Charles F D Sacobie, H A Burke, Santosh P Lall, Tillmann J BenfeyAbstract:Triploids are used in aquaculture because they are sterile and do not undergo preharvest loss in flesh quality. Despite this advantage, they do not always perform as well as diploids when fed commercial diets. This study investigated whether differences in dietary energy utilization might explain this reduced performance. Dietary lipid levels were adjusted to supply diets with 22.7, 23.6 or 24.4 MJ kg−1 gross energy and fed to juvenile diploid and triploid brook charr. Fish were fed to satiation twice daily in a 70-day growth trial, with samples collected at days 0 and 70 for proximate composition and plasma insulin-like growth factor I (IGF-I) analysis. This was followed by a digestibility trial using the same diets to determine apparent digestibility coefficients. Triploids had lower growth rates and condition factor than diploids on all three diets, but there was no effect of ploidy on feed conversion efficiency. Triploids also had lower whole-body lipid content, but equal protein content, which resulted in lower energy content at both days 0 and 70. There was no effect of diet or ploidy on plasma IGF-I concentrations. Triploidy did not affect diet digestibility, suggesting that the reduced performance of triploids is due to a difference in metabolism and energy utilization.
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effectiveness of Triploidy as a management tool for reproductive containment of farmed fish atlantic salmon salmo salar as a case study
Reviews in Aquaculture, 2016Co-Authors: Tillmann J BenfeyAbstract:Atlantic salmon (Salmo salar) dominates aquaculture production in its native North Atlantic range, raising concerns about the impacts of escaped farmed fish on wild populations. While physical confinement and operational management practices have improved steadily with the development of this industry, some escapes are inevitable. In the absence of effective measures for the rapid recapture of escaped fish, the only practical method currently available to minimize their impacts on wild populations is to ensure that they are female triploids and therefore reproductively sterile. The technology for producing all-female triploid populations of Atlantic salmon is simple and easily applied on a commercial scale, and routinely results in populations that are entirely female and >98% triploid. Aside from sterility, there are no population-wide phenotypic effects of Triploidy, although triploids do tend to perform less well than diploids with respect to commercial culture characteristics and are also less likely than escaped diploids to outcompete or displace native salmon. Some uncertainties exist with respect to their disease resistance and their potential to become reservoirs for the spread of pathogens to wild populations. If the spawning potential of escaped farmed Atlantic salmon is deemed to pose an unacceptable risk to native populations, then all-female triploid populations could be used as an alternative to reduce risk. Research should continue to focus on improving triploid performance through breeding programmes and optimization of husbandry conditions (including nutrition, environmental conditions and fish health), with the goal of making triploids an attractive option for fish farmers.
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use of sterile triploid atlantic salmon salmo salar l for aquaculture in new brunswick canada
Journal of Materials Science, 2001Co-Authors: Tillmann J BenfeyAbstract:Induced Triploidy is the only effective method currently available for mass production of reproductively sterile salmonids for aquaculture. Repeated studies at the Atlantic Salmon Federation's hatchery (St Andrews, New Brunswick, Canada) have shown only minor differences between triploids and diploids in survival to S1 smolt age (15 months), percentage of the population which became S1 smolts, and mean S1 smolt size. However, a similar study at a commercial hatchery was terminated because of exceptionally high mortality of triploids prior to the start of feeding. Marine growout trials in sea cages showed that triploids grew well in seawater, but had reduced survival rates (leading to a 5-15% reduction in yield at harvest) and high rates of jaw abnormalities. Similar results have been reported elsewhere. Although induced Triploidy can be used effectively as a management tool to ensure lack of reproduction, there is at present little support of the aquaculture industry to switch to their large-scale use. In light of fundamental biological differences, it is perhaps naive to expect triploids to perform as well as diploids using standard culture methods. Triploids should be treated as a new “species” for aquaculture development, beginning with research to determine their optimum rearing requirements.
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the reproductive physiology of three age classes of adult female diploid and triploid brook trout salvelinus fontinalis
Fish Physiology and Biochemistry, 2000Co-Authors: D Schafhausersmith, Tillmann J BenfeyAbstract:Triploid female fish show impaired gametogenesis and are unable to produce viable offspring. The reproductive physiology of artificially-induced triploid female salmonids has been well described up until the time of first sexual maturation in diploids, but few reports exist for older triploids. This study reports the influence of Triploidy on growth, ovarian development and reproductive endocrinology among three age classes of female brook trout (Salvelinus fontinalis) in comparison to sibling diploids. Triploids were larger than diploids for most of the study period, but the difference was statistically significant only during maturation and spawning of 2+ diploids. Plasma estradiol-17β (E2), testosterone (T) and vitellogenin (VTG) levels in triploids were generally lower than in diploids, and VTG was the only parameter to show seasonal fluctuations resembling those of diploids. Triploids showed significantly lower GSI and total oocyte number than diploids of similar age, and only half of all triploids sacrificed during the study (n=56) had developing oocytes in their ovaries. At age 3+, 13 of 19 triploid females had oocytes at various stages of development, including perinucleolar, yolk vesicle and yolk globule stages. In addition, three of these fish had collectively produced 72 mature stage oocytes. Thus, whereas diploid brook trout can produce mature oocytes as two-year-olds, triploids cannot do so until four years of age, with the number of mature oocytes being greatly reduced.
Tom Hansen - One of the best experts on this subject based on the ideXlab platform.
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water temperature and oxygen the effect of Triploidy on performance and metabolism in farmed atlantic salmon salmo salar l post smolts
Aquaculture, 2017Co-Authors: Florian Sambraus, Tom Hansen, Rolf Erik Olsen, Thomas Torgersen, Mette Remen, Per Gunnar FjelldalAbstract:Abstract The use of sterile triploids in Atlantic salmon aquaculture would mitigate the environmental risks associated with introgressive hybridization between escaped farmed and wild Atlantic salmon. However, production of farmed triploid salmon is limited due to reports of poorer growth and higher mortality when compared to diploids, in particular under sub-optimal environmental conditions. To address these concerns, we monitored triploid and diploid Atlantic salmon post-smolts at temperatures between 3 and 18 °C and 100% oxygen saturation (O2 sat), and additional periods of 60% O2 sat (hypoxia) at 6 or 18 °C, respectively. Feed intake and oxygen consumption rate were monitored throughout the experimental period. Muscle and blood samples were collected at 100 and 60% O2 sat at 6 and 18 °C for analysis of white muscle energy phosphates (creatine phosphate, adenosine triphosphate) and carbohydrate fuels (glucose, glycogen) as well as blood clinical chemistry (whole blood: hematocrit; plasma: Na+, K+, Cl−, glucose, lactate, pH, triacylglycerol). Mortality was similar between ploidies, but higher in triploids compared to diploids during reduced O2 sat at 18 °C. Compared to diploids, triploids had higher feed intake (% biomass) at ≤ 9 °C, but lower feed intake at ≥ 15 °C. Feed intake peaked at 12 and 15 °C for triploids and diploids, respectively. Triploids progressively reduced feed intake with increasing temperature after peak feeding, indicating reduced scope for specific dynamic action with increasing water temperature. During hypoxia, triploids had lower feed intake than diploids at 6 and 18 °C. The difference in feed intake was not associated with any ploidy effect on body weight gain or feed conversion ratio, but triploids had greater body length growth compared to diploids. At ≥ 15 °C triploids consumed less oxygen than diploids. In the white musculature, the only observed difference between ploidies was a lower level of glycogen in triploids compared to diploids at 18 °C and 100% O2 sat. In the blood plasma, the concentration of ions was lower and glucose level higher in triploids compared to diploids at 18 °C and 60% O2 sat. The results of this study indicate that triploid Atlantic salmon post-smolts can substitute diploids, but are less tolerant to high seawater temperature and low O2 sat. For sea-cage farming of triploid salmon post-smolts, this would favour production areas with maximum temperatures of 15 °C and sufficient oxygen. Statement of Relevance This study demonstrates that triploid Atlantic salmon post-smolts have lower temperature optima for feeding and growth than diploids, a similar physiological response to high temperatures, but higher mortality under suboptimal conditions. Consequently triploid Atlantic salmon post-smolts may be well suited for commercial farming in geographical regions with moderate water temperatures in the summer and autumn months.
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effect of water oxygen level on performance of diploid and triploid atlantic salmon post smolts reared at high temperature
Aquaculture, 2015Co-Authors: Tom Hansen, Rolf Erik Olsen, Lars Helge Stien, Frode Oppedal, Thomas Torgersen, O Breck, Mette Remen, Tone Vagseth, Per Gunnar FjelldalAbstract:Abstract Sterilization by triploid induction prevents interbreeding between escaped farmed salmon and wild stocks, but reduced performance of triploids at high seawater temperatures has been reported. As high temperature may be followed by limited oxygen (O 2 ) supply in net cages, this study compared the effect of reducing O 2 from 100% to 70% of air saturation (termed hypoxia) on parameters of production performance (feed intake, growth, feed conversion ratio, mortality), and physiological status (plasma K + , Cl − , Na + , osmolality, glucose, creatinine (Cr), bilirubin, triacylglycerol (TAG) and alkaline phosphatase (ALP) concentrations) in triploid versus diploid Atlantic salmon kept at high seawater temperature (19 °C). Two triplicate groups of diploid and two triplicate groups of triploid Atlantic salmon post-smolts were acclimated to 10 °C and 100% O 2 before experiment start up. During the experiment, temperature was maintained at 10 °C for 10 days, increased to 19 °C over 9 days and kept stable at 19 °C until the experiment ended (day 51). From day 22 to 51, the O 2 level was reduced from 100% O 2 to 70% O 2 in one diploid and one triploid group. The abbreviated group names are 2N100, 2N70, 3N100 and 3N70. Triploidy led to reductions of feed intake and growth, and this effect was amplified by reducing O 2 from 100% to 70% O 2 . Analyses from blood samples drawn on day 51 show that plasma levels of Cl − , TAG, ALP and bilirubin were lowered in triploids in general, and that plasma Cr levels trebled and plasma K + levels dropped in triploids subjected to 70% O 2 for 29 days. Mortality was also significantly higher in the 3N70 group. According to these effects, the following order of production performance is suggested at high seawater temperature (best to worst): 2N100 > 2N70 ≥ 3N100 > 3N70. An interesting difference in the behavior between diploid and triploid fish was observed during the experiment: triploids generally moved against the tank water current, ram ventilating, as opposed to diploids, which displayed normal gill ventilation and were in part moving along with the current. The inability of triploid Atlantic salmon to withstand high temperature in combination with moderate hypoxia could set limitations to the geographical distribution of triploid salmon farming.
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the effect of Triploidy on vaccine side effects in atlantic salmon
Aquaculture, 2014Co-Authors: Thomas W K Fraser, Tom Hansen, Kevin A Glover, Ian Mayer, Jon Egil Skjaeraasen, Florian Sambraus, Per Gunnar FjelldalAbstract:Abstract Vaccination against bacterial diseases is an important aspect of commercial salmon production, but is known to have a number of unwanted side-effects including reduced growth, abdominal adhesions, and vertebral deformities. Our study objective was to compare these side-effects between diploid and sterile triploid salmon, the use of which would prevent genetic interactions between escaped farmed and wild salmon. A full factorial cross of vaccinated and unvaccinated, diploid and triploid, yearling (1 +) and under-yearling (0 +) mixed sex salmon were reared in triplicate in freshwater before common rearing in sea cages for 12–15 months. To further examine how ploidy may influence welfare with respect to vertebral deformities, a set of wild caught salmon were examined. Unvaccinated fish were larger (9% at termination) than vaccinated fish, but there was no effect of vaccination on skeletal deformities. In general, triploids grew as well or better in freshwater, but poorer in seawater compared to diploids, resulting in diploids being 12% larger than triploids at termination irrespective of smolt regime. In addition, triploids had a higher prevalence of fish with a least one deformed vertebra in 1 + smolts compared to diploids (34 vs 8%, respectively). However, vertebral compressions and fusions were observed in both ploidy, but were not apparent in the wild caught adult salmon control fish. Ploidy effects on the response to vaccination were limited to triploids having significantly higher vaccine-induced abdominal adhesion scores in 0 + smolts compared to diploids. Triploidy also prevented males becoming larger than females in vaccinated 0 + smolts in contrast to all other ploidy, vaccination, smolt regime combinations where males became the largest (8–12% at termination). Finally, notable levels of sexual maturation occurred in the male 0 + smolts, but fewer triploids matured as post-smolts or grilse in comparison to diploids. Based on our results, for best welfare practices the timing of vaccination may need to be altered when producing 0 + triploid smolts.
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vertebral deformities in triploid atlantic salmon salmo salar l underyearling smolts
Aquaculture, 2010Co-Authors: Per Gunnar Fjelldal, Tom HansenAbstract:Abstract This study investigated the prevalence of vertebral deformities in triploid and diploid Atlantic salmon smolts. Four full-sibling families were either subjected to hydrostatic pressure (655 bar, 6.25 min, 8 °C) (triploid) 37 min post-fertilization, or were maintained as untreated controls (diploid), and then reared to the smolt stage. Some 800 fish (100 per ploidy/family group) were palpated for vertebral deformities, and 480 (60 per ploidy/family group) of these were selected at random for radiography and evaluation for vertebral deformities. There was a significantly higher prevalence of triploid individuals classified as spinally deformed during palpation (triploids; 1–3%, diploids; 0–1%), and of individuals with one or more deformed vertebrae on radiographs (triploids; 30–35%, diploids; 8–13%). The trunk region (V9-30) of the vertebral column was the predominant location for deformities in triploids, with vertebra number 24 being the most often affected. Of the triploids, 7.6% had a malformation in this particular vertebra, which is located beneath the dorsal fin.
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Comparative seawater performance and deformity prevalence in out-of-season diploid and triploid Atlantic salmon (Salmo salar) post-smolts.
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2010Co-Authors: Eric Leclercq, Damian Fison, Meritxell Diez-padrisa, Tom Hansen, John Taylor, Per Gunnar Fjelldal, Herve MigaudAbstract:Abstract The use of sterile triploid stock in the Atlantic salmon ( Salmo salar , L) farming industry is the only commercially available means to prevent the ecological impact of domesticated escapees. This study compared the seawater (SW) performance and deformity prevalence of diploid and triploid post-smolts from 2 full-sib families produced out-of-season. Triploids completed smoltification 4 weeks earlier and at a significantly higher body-weight. Growth and survival in SW were not significantly affected by ploidy. The incidence of external deformities, dominated by jaw malformation, was ~ 12% in triploids and below 5% in diploids. Vertebral deformities were more prevalent in the fastest growing triploid family only. Heart morphometry differed between ploidies which may relate to a higher cardiac workload in triploids. No clear alteration of the gill apparatus was detected. The most significant detrimental effect of Triploidy was on the rate and severity of cataract that were observed from August onward (50% and 92% of diploids and triploids respectively affected after 1-year in SW). At that time, cataracts were diagnosed by histological examinations as irreversible with a probable osmotic origin which could arise from factors such as water quality, nutritional deficiencies or thermal variations. This study warrants further research aiming at adapting rearing practices to the needs of triploid stocks as to improve their performance and welfare.
J A Nell - One of the best experts on this subject based on the ideXlab platform.
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studies on triploid oysters in australia xiii performance of diploid and triploid sydney rock oyster saccostrea glomerata gould 1850 progeny from a third generation breeding line
Aquaculture, 2004Co-Authors: Rosalind E. Hand, J A Nell, Peter A ThompsonAbstract:The performance of diploid and triploid selected and control oysters was compared at three sites to determine if the improvements in growth of selected oyster line (L2) Sydney rock oysters were additive to the faster growth of triploids. After a grow-out period of 32 months, both mean whole weights and shell heights were in the order: L2 triploids>control triploids>L2 diploids>control diploids. Mean whole weights of different oyster lines were all significantly different (p<0.05). A significant (p=0.02) site×line interaction effect on oyster weights was also detected. On average, L2 triploids were 74% heavier than control diploids, indicating that growth improvements from selective breeding and Triploidy were at least additive and could reduce the time to market by at least 10 months. Oyster type had no effect on the meat condition index, percent cavity volume, percent shell weight or cumulative mortality, but did affect whole weight/shell height ratios after 21 months grow-out.
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studies on triploid oysters in australia xii gonad discolouration and meat condition of diploid and triploid sydney rock oysters saccostrea commercialis in five estuaries in new south wales australia
Aquaculture, 1999Co-Authors: Rosalind E. Hand, J A NellAbstract:Abstract The relative performance, in terms of meat condition, of triploid compared to diploid Sydney rock oysters varied among five widely distributed sites in New South Wales (NSW). Over the final year on leases, ploidy, month and the ploidy×month interaction had a significant effect on meat condition at all sites except for ploidy at the southern, Lake Pambula site. From March to December (autumn to the first month of summer), triploid condition indices were higher, or not significantly different from those of diploids at all sites. Condition indices of triploids were higher than those of diploids from May to November/December at four of the five sites. A higher condition index (CI) of triploids became apparent later in the sampling period for the Lake Pambula site in comparison to the remaining four sites. Triploid Sydney rock oysters were susceptible to brown discolouration of the gonad surface. Discolouration occurred in localised areas of the gonad and was not correlated to CI except for triploids at Lake Pambula. As discolouration was less noticeable during cooler months of the year, thus, coinciding with the generally superior condition of triploids relative to diploids during winter and spring, triploids remain a viable winter crop for farmers throughout NSW.
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studies on triploid oysters in australia effect of initial size on growth of diploid and triploid sydney rock oysters saccostrea commercialis iredale roughley
Aquaculture Research, 1999Co-Authors: Rosalind E. Hand, J A Nell, D D Reid, I R Smith, G B MaguireAbstract:In a 2-year grow-out trial, triploid Sydney rock oysters, Saccostrea commercialis (Iredale and Roughley), from two initial size grades grew faster (in terms of both mean whole weight and shell height) than the equivalent initial size grades of sibling diploids (P < 0.05). Small size grade triploids caught up with and had significantly heavier (P < 0.05) final whole weights than large size grade diploids after a 2-years grow-out period. The initial size grade had a significant effect on final mean whole weight and shell height for both ploidy types. After the 2-years grow-out trial, the final mean whole weights (but not shell heights) of small and large diploids (35.8 ± 0.6 g and 39.4 ± 0.5 g, respectively) were significantly different (P < 0.05). Small and large triploids grew at a similar rate for the first 18 months despite the significantly (P < 0.05) heavier final mean weight of large grade triploids (48.4 ± 0.8 g and 61.2 ± 0.7 g, respectively). The effect of the initial size grade on subsequent growth of both diploid and triploid oysters which was demonstrated in the present study is of significant commercial value to hatchery and nursery operators as well as growers of single seed oysters. In addition, small-grade triploids appeared to be more valuable in terms of potential growth rate than all diploid grades. There was no significant difference in the final percentage Triploidy between small and large grade triploids. A large proportion of diploid/triploid mosaicism was detected in adult oysters.
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studies on triploid oysters in australia vi gonad development in diploid and triploid sydney rock oysters saccostrea commercialis iredale and roughley
Journal of Experimental Marine Biology and Ecology, 1996Co-Authors: E S Cox, M S R Smith, J A Nell, G B MaguireAbstract:Abstract Triploid Sydney rock oysters, Saccostrea commercialis (produced using cytochalasin B to treat newly fertilised eggs), were sampled from 22–34 months of age to encompass a full reproductive season. A comparative assessment of the extent of gametogenesis was made for both diploid and triploid Sydney rock oysters. It was necessary to develop separate staging criteria for the triploids. Triploid gametogenesis was highly retarded compared to the diploids. The extent of retardation of gametogenesis in the triploids was more severe than that observed for triploid Pacific oysters. In particular, triploid females developed abnormally and follicle branching was severely retarded with few mature ova present. Development in the male triploid appeared to halt at spermatocyte formation; on the few occasions that spermatids were present they were sparsely distributed throughout the gonad. In the thirteen months of sampling, there was no evidence of spawning in the triploids. Very few hermaphrodites were found in either diploids or triploids sampled. Sex ratios showed little change over time for diploids and for triploid males but the incidence of triploid females increased between January and May. The gonad area indices for triploids (sexes combined) were consistently much lower than for those of either diploid males or females.
Standish K. Allen - One of the best experts on this subject based on the ideXlab platform.
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Genetic improvement for disease resistance in oysters: A review.
Journal of Invertebrate Pathology, 2015Co-Authors: Lionel Dégremont, Céline Garcia, Standish K. AllenAbstract:Oyster species suffer from numerous disease outbreaks, often causing high mortality. Because the environment cannot be controlled, genetic improvement for disease resistance to pathogens is an attractive option to reduce their impact on oyster production. We review the literature on selective breeding programs for disease resistance in oyster species, and the impact of Triploidy on such resistance. Significant response to selection to improve disease resistance was observed in all studies after two to four generations of selection for Haplosporidium nelsoni and Roseovarius crassostrea in Crassostrea virginica, OsHV-1 in Crassostrea gigas, and Martelia sydneyi in Saccostrea glomerata. Clearly, resistance in these cases was heritable, but most of the studies failed to provide estimates for heritability or genetic correlations with other traits, e.g., between resistance to one disease and another. Generally, it seems breeding for higher resistance to one disease does not confer higher resistance or susceptibility to another disease. For disease resistance in triploid oysters, several studies showed that Triploidy confers neither advantage nor disadvantage in survival, e.g., OsHV-1 resistance in C. gigas. Other studies showed higher disease resistance of triploids over diploid as observed in C. virginica and S. glomerata. One indirect mechanism for triploids to avoid disease was to grow faster, thus limiting the span of time when oysters might be exposed to disease.
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triploid catarina scallop argopecten ventricosus sowerby ii 1842 growth gametogenesis and suppression of functional hermaphroditism
Aquaculture, 2000Co-Authors: Cesar A Ruizverdugo, Standish K. Allen, José L. Ramirez, Ana M IbarraAbstract:Abstract Triploidy was induced in catarina scallop, Argopecten ventricosus, using two concentrations of cytochalasin-B (CB). Growth of triploid scallops exceeded that of diploids in all evaluated traits. The largest percent difference between the diploid control group and the treated groups was seen after diploid scallops reached the peak of sexual maturation and began spawning. The gonad of triploid scallops was easily recognizable by visual inspection because of a brownish discoloration and lack or few egg masses present. That characteristic allowed for the separation of ‘putative triploids’ (PTs), which when compared with diploid scallops from within the same treatment (treated diploids), had a significantly larger muscle weight than the differences seen between treated and control groups. Gametogenesis and the condition of hermaphroditism in this normally functional hermaphrodite were greatly affected by the triploid condition. In the female portion of the gonad, few oocytes developed. The male portion of the gonad was arrested early during development, and the male acini were replaced by female acini, producing all female gonads in increasing percentages during the culture period, suppressing the normal condition of hermaphroditism. Oocytes of diploids were larger than those of triploids early in the culture, probably because of delayed maturation in triploids. Later during the culture, oocytes of triploids were larger than those of diploids only when compared with treated diploids.
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reproductive potential and genetics of triploid pacific oysters crassostrea gigas thunberg
The Biological Bulletin, 1994Co-Authors: Ximing Guo, Standish K. AllenAbstract:The reproductive potential and genetics of Triploidy were studied in the Pacific oyster. DNA content in sperm from triploids showed a single peak at 1.5c as determined by flow cytometry. In eggs from triploids, trivalents were the dominant form of synapsed chromosomes, although the degree of synapsis varied considerably within and among females. Some eggs went through complete synapsis and formed 10 trivalents, chromosomes; most had a mixture of 11-13 trivalents, bivalents, and univalents. Factorial matings were produced from diploid (D) and triploid (T) parent oysters, creating four crosses: DD, DT, TD, and TT (female first). Gametes from triploids were fully capable of fertilization. After fertilization, eggs from triploids went through two meioses and released two polar bodies as diploid eggs did. Karyological analyses showed that average ploidy of the resultant embryos was 2.0 n for DD, 2.46 n for DT, 2.52 n for TD, and 2.88 n for TT. Survival of fertilized eggs to metamorphosis and settlement was about 21% for DD, but considerably lower on other crosses: 0.0007% for DT, 0.0463% for TD, and 0.0085% for TT. Nine months after matings, all survivors from DT crosses were diploid. Survivors from TD crosses consisted of 33% diploids, 57% triploids, and 10% tetraploids. Survivors from the TT crosses consisted of 90% triploids, 4% diploids, and 6% mosaics. We hypothesize that differences in ploidy composition between DT and TD embryos and survivors were caused by pro-egg segregations that favor the retention, rather than loss, of extra chromosomes in the egg. The reproductive potential of triploids and evolutionary implications are discussed.
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sex determination and polyploid gigantism in the dwarf surfclam mulinia lateralis say
Genetics, 1994Co-Authors: Ximing Guo, Standish K. AllenAbstract:Mulinia lateralis, the dwarf surfclam, is a suitable model for bivalve genetics because it is hardy and has a short generation time. In this study, gynogenetic and triploid. M. lateralis were successfully induced. For gynogenesis, eggs were fertilized with sperm irradiated with ultraviolet light and subsequently treated with cytochalasin B to block the release of the second polar body (PB2). Triploidy was induced by blocking PB2 in normally fertilized eggs. The survival of gynogenetic diploids was very low, only 0.7% to 8 days post-fertilization (PF), compared with 15.2% in the triploid groups and 27.5% in the normal diploid control. Larvae in all groups metamorphosed at 8-10 days PF, and there was no significant post-larval mortality. At sexual maturation (2-3 months PF), all gynogenetic diploids were female, and there was no significant difference (P > 0.05) in sex ratio between diploids and triploids. These results suggested that the dwarf surfclam may have an XX-female, XY-male sex determination with Y-domination. Compared with diploids, triploids had a relative fecundity of 59% for females and 80% for males. Eggs produced by triploid females were 53% larger (P 0.33) different from normal diploid females, suggesting that inbreeding depression was minimal in meiosis II gynogens. Triploid clams were significantly larger (P < 0.001) than normal diploids. We hypothesize that the increased body-size in triploids was caused by a polyploid gigantism due to the increased cell volume and a lack of cell-number compensation.
