Survival, growth, sexual maturation and reproduction of brook charr, Salvelinus fontinalis (Mitchill), Arctic charr, Salvelinus alpinus L., and their hybrids     

S Dumas  J M Blanc  F Vallée  C Audet  J de la Noüe 《Aquaculture Research》1996,27(4):245-253

Survival of hybrids (FA, AF) between brook charr, Salvelinus fontinalis (Mitchill), (FF) and Arctic charr, Salvelinus alpinus L., (AA) were compared at three fish farms. Survival of hybrids and Arctic charr was impaired in warm water. In cold water, brook charr and hybrids showed similar survival percentages until the spawning period. Each spawning period was followed by an increase of mortality, but to a much higher degree in brook charr. Growth was studied in the best (cold water) fish farm. During the first 2 years of rearing, brook charr had the highest relative weight. The weight of the two hybrids approached that of brook charr in the third year because of the drastic decrease of growth rate in brook charr after the spawning period. No differences between genotypes of either females or males could be detected in the eviscerated weights, the dressing percentages, or the gonado-somatic indexes. The two hybrids matured sexually, but their sperm quality was inferior to that of the pure species. Crosses between the 4-year-old breeders from the F1 population (FF, FA, AF and AA) were achieved. Survival from the eyed stage to 6 weeks post-hatching was significantly lower in F2 progeny than in back-crosses or pure species crosses. Even though the survival following spawning periods and the total biomass produced were better in hybrids than in brook charr raised in cold water, we believe the farming of this hybrid should not be carried out. The full development of sexually mature hybrids does not resolve problems linked with precocious sexual maturation in brook charr farming carried out in eastern Canada.  相似文献   

Stimulatory effect of ammonium lignosulfonate on germination and growth of Phlebiopsis gigantea spores     

M. T. Dumas 《Forest Pathology》2011,41(3):189-192

Ammonium lignosulfonate (ALS) was found to stimulate the germination and growth of Phlebiopsis gigantea. When incubated in 1% and 2.5% solutions germination rates were higher and germ tubes longer at all temperatures tested when compared to water controls. When ALS was used to inoculate P. gigantea into red pine stumps the spores had germinated and hyphae were easily observed after 16 h but no germination had occurred in the stumps treated with oidia in water.  相似文献   

Light-mediated influence of three understorey species (Calluna vulgaris, Pteridium aquilinum, Molinia caerulea) on the growth of Pinus sylvestris seedlings     

No��mie Gaudio  Philippe Balandier  Gwena?l Philippe  Yann Dumas  Fr��d��ric Jean  Christian Ginisty 《European Journal of Forest Research》2011,130(1):77-89

Depending on its developmental and morphological characteristics, shrubby or herbaceous understorey vegetation interacts differently with tree seedlings during the regeneration process. In acidic temperate forests, three common understorey plant species??Calluna vulgaris (L.) Hull, Pteridium aquilinum (L.) Kuhn in Kersten, Molinia caerulea (L.) Moench??are known to rapidly colonize forest gaps. Therefore, they often develop at the expense of light-demanding Scots pine (Pinus sylvestris L.) seedlings. An experiment was set up in a nursery in central France to mimic early competition occurring in a newly created gap between Scots pine seedlings and these three common understorey species (young forest-harvested individuals planted at 5 densities from 0 to 57 plants m^?2). Pine seedling survival and growth (height, diameter, shoot and root biomass) and a functional trait (leaf mass on an area basis, LMA) were measured for 2 years, and cross-analysed against plant density, plant cover and available light. When understorey plant density increased, pine seedling diameter growth and biomass were negatively affected by all three plant species; height growth only slowed beneath Pteridium. These negative effects were closely linked to competition for light beneath Pteridium and Molinia. The application of the Beer?CLambert law gave an extinction coefficient k that was high for Pteridium, intermediate for Molinia and much lower for Calluna. LMA was confirmed as an effective foliar trait to reflect the degree of stress undergone by pine seedlings.  相似文献   

Effect of Stocking Density on the Growth and Survival of Spotted Sand Bass Paralabrax maculatofasciatus Larvae in a Closed Recirculating System     

Carlos A.  Alvarez-González  José L.  Ortiz-Galindo  Silvie  Dumas  Sergio F.  Martínez-Díaz  Dora E.  Hernández-Ceballos  Tanos Grayeb  -Del Alamo  Manuel  Moreno-Legorreta  Renato  Penta-Martínez Roberto  Civera-Cerecedo 《Journal of the World Aquaculture Society》2001,32(1):130-137

Abstract.— The effect on growth and survival of the initial stocking density (50, 100, 150, and 200 larvae/ L) in larval rearing of spotted sand bass was evaluated over 30 d in a closed recirculating system. Larvae were fed with rotifers, copepods, nauplii and adult Artemia , and spotted sand bass yolk-sac larvae. Water quality was monitored daily. The notochordal or standard length of sampled larvae was measured by image analysis. Specific growth rates at each density were compared by covariance analysis. Survival was estimated from day 15 to the end of the experiment, when a resistance test was used to evaluate the juvenile quality among densities. At the end of the experiment, mean standard length of larvae at lower densities was significantly larger ( P < 0.05) than at higher densities. Higher specific growth rates were found at lower densities. Significantly higher survival ( P < 0.05) was recorded for the lowest density, but the highest number of harvested fish was obtained with the highest densities (150 and 200 larvae/L). The lowest density also showed the significantly ( P < 0.05) higher survival after using a resistance test. We conclude the highest density can be used in larval rearing of spotted sand bass. However, better survival, growth, and seed quality are obtained at the lowest density. To recommend an optimal density for this specie, it is necessary to improve the water quality in the culture system and to make a cost-benefit study.  相似文献   

Comparison of the effects of glyphosate and related compounds on indole-3-acetic acid metabolism and ethylene production in tobacco callus     

T. T. Lee  T. Dumas  J. J. Jevnikar 《Pesticide biochemistry and physiology》1983,20(3):354-359

Pretreatment of tobacco callus (Nicotiana tabacum L.) with glyphosate and related compounds promoted to a different degree the metabolism of radiolabeled indole-3-acetic acid ([2-¹⁴C]IAA) by increasing both conjugation and oxidation, and consequently lowered the level of free [2-¹⁴C]IAA. At identical concentrations, glufosinate ammonium was more active than glyphosate whereas glyphosine and aminomethylphosphonic acid were less active. These compounds also selectively reduced ethylene production and inhibited fresh-weight growth of tobacco callus. The activities of the tested compounds on IAA metabolism were correlated with those on inhibition of growth, suggesting that, under the experimental condition, the effect on IAA metabolism was a major contribution to their toxic action. This information may be useful for the design and testing of new herbicides and plant growth regulators of this type.  相似文献   

Intensive fattening of Adamaoua zebus. I. Comparison of different feeding systems (1970)     

P Lhoste  R Dumas 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1972,25(2):259-280

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Variations saisonnieres des composantes de l'alcalinite des eaux dans le haut-estuaire du fleuve Saint-Laurent (Quebec)     

Jean-Pierre Dumas  Leroy Pazdernik 《Water, air, and soil pollution》1983,20(4):413-424

Measurements of the total alkalinity and its components have been made on waters collected from the St.` Lawrence River during the year 1980–1981. Analyses of the total inorganic carbon, the borates, the phosphates and the silicates along with the pH and the total alkalinity permitted an evaluation of each component. In all seasons, the carbonate system was the major component (96%) of the total alkalinity. The residual alkalinity accounting for only 2 to 3% and obtained by the difference between the total alkalinity and the sum of the components appears attributable to weak organic acids. The saturation state of calcite coincided with a river saturated by dissolved calcium carbonate during the summer season and only 45% saturated during the winter season.  相似文献   

Development of digestive enzyme activity in spotted rose snapper,Lutjanus guttatus (Steindachner, 1869) larvae     

I. Moguel-Hernández  R. Peña  H. Nolasco-Soria  S. Dumas  I. Zavala-Leal 《Fish physiology and biochemistry》2014,40(3):839-848

We describe digestive enzyme activity during the larval development of spotted rose snapper, Lutjanus guttatus. Trypsin, chymotrypsin, leucine aminopeptidase, pepsin, amylase, lipase, and acid and alkaline phosphatase activities were evaluated using spectrophotometric techniques from hatching through 30 days. The spotted rose snapper larvae present the same pattern of digestive enzyme activity previously reported for other species in which pancreatic (i.e., trypsin, chymotrypsin, amylase, and lipase) and intestinal (i.e., acid and alkaline phosphatases and leucine aminopeptidase) enzymatic activities are present from hatching allowing the larvae to digest and absorb nutrients in the yolk-sac and live prey by the time of first feeding. The digestive and absorption capacity of the spotted rose snapper increases during the larval development. A significant increase in individual activity of all enzymes occurs at 20 DAH, and around 25 DAH, the juvenile-type of digestion is observed with the appearance of pepsin secreted by the stomach, suggesting that maturation of the digestive function occurs around 20–25 DAH. Our results are in agreement with a previous suggestion that early weaning may be possible from 20 DAH. However, the patterns of enzymatic activities reported in our study should be considered during the formulation of an artificial diet for early weaning of the spotted rose snapper.  相似文献   

Effect of incubation temperature on the embryonic development and yolk‐sac larvae of the Pacific red snapper Lutjanus peru (Nichols & Murphy, 1922)     

Renato Peña  Silvie Dumas  Iram Zavala‐Leal  Mauricio Contreras‐Olguín 《Aquaculture Research》2014,45(3):519-527

The effect of incubation temperature on embryonic development and yolk‐sac larva of the Pacific red snapper Lutjanus peru were evaluated by testing the effect of 26, 28 and 30°C, as this is the natural thermal interval reported during the spawning season of Pacific red snapper in the Gulf of California, Mexico. Sixteen developmental stages were observed. The incubation temperature affected the rate of development and time to hatching, being shorter at 30 than at 26°C, but no significant effect (P < 0.05) on larval length at hatching was registered. The depletion rate of yolk sac and oil globule was affected by incubation temperature particularly during the first 12 h post hatching (hph). At the end of the experiment (48 hph), significantly (P < 0.05) larger larvae were recorded at 26°C (TL = 3.22 ± 0.01 mm) than at 28° (TL = 3.01 ± 0.02 mm) and 30°C (TL = 2.97 ± 0.05 mm). Incubation of newly fertilized eggs at 26°C produces larger larvae, which may help to improve feeding efficiency and survival during first feeding.  相似文献   

Egg quality criteria in Pacific red snapper (Lutjanus peru)          下载免费PDF全文

Ivette Moguel‐Hernández  Renato Peña  Héctor Nolasco‐Soria  Silvie Dumas  Patricia Hinojosa‐Baltazar 《Aquaculture Research》2015,46(4):909-917

The aim of this study was to evaluate the biochemical parameters used as possible determinants of egg quality in Pacific red snapper (Lutjanus peru). Fertilized eggs of eight spawns were obtained by hormonal induction. Egg quality criteria, including abnormal cleavage (AC), hatching percentage (HR) and survival percentage at first feeding (SR) were recorded. Samples were taken during embryonic development and from yolk‐sac larvae. Proteins, energetic metabolite concentrations and metabolic and digestive enzyme activities were determined using colorimetric methods. Pearson's correlation, and simple and multiple regression models were performed using the biochemical parameters as the independent variables and AC, HR and SR as the dependant variables. Glucose‐6‐phosphatase activity (AC r = 0.87; HR r = ?0.65; SR r = ?0.67) and fructose concentration (AC r = ?0.64; HR r = 0.54; SR r = 0.64) were the only biochemical parameters to be strongly correlated with the three egg quality criteria. The use of multiple regression models increased the regression coefficient of the three quality criteria. Fructose, glucose and glucose‐6‐phosphatase were involved in all multiple regression models. The models proposed in this study may be used to explain egg quality for Pacific red snapper and their use as predictors of egg quality is discussed.  相似文献