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The use of decapsulated Artemia cysts as food for ide, Leuciscus idus (L.), larviculture was investigated. Three days after hatching, the larvae were fed on different diets: (a) dried decapsulated Artemia cysts, (b) Artemia nauplii, (c) Artemia nauplii for 7 days and then trout starter, (d) diet for marine larvae (manufactured artificial diet), (e) trout starter. After a 21-day rearing period, the highest survival rate was obtained with the larvae receiving decapsulated Artemia cysts. Feeding of the larvae with artificial diets resulted in a significantly lower survival rate compared to the other groups. At the end of the experiment, the larvae fed on Artemia nauplii gained significantly higher length compared to the other groups. Feeding different artificial diets resulted in significantly lower average mean length and weight compared to the other groups.
Ide spermatozoa were genetically inactivated using ultraviolet (UV) irradiation. The highest survival of haploid embryos was noted in the group treated with UV for 5 min (dose 1920 J m-2). High-temperature shock influenced the suppression of the second polar body in ide oocytes. The highest survival rate of diploid gynogenotes (below 10%) was observed in groups shocked at 12 min after egg insemination for 3 min. Eggs shocked later in time exhibited lower survival rates.
The aim of the study was to describe the embryonic development of ide. Eggs fertilized with the in vitro method were incubated under controlled laboratory conditions in continually aerated water at a temperature of 16°C. The study indicated that ide eggs swell a maximum of 2 h after fertilization (80.5%). The eggs are entirely opaque in the early stages of development up to the formation of small-celled blastulas. This is a transitional stage, and the egg chorions become fairly transparent from the moment embryos formed on the yolk spheres. The first embryonic movements inside the egg are observed 75 h after fertilization. Embryo survival decreased gradually throughout development and 85% hatched. The larvae began hatching after 114 h of development and finished after 135 h. The ide larvae broke through the egg envelope with their tails, which were the first parts of the embryos to emerge from the eggs, followed by the rest of the bodies. Properly developed larvae comprised 92% of the hatchlings. Two types of morphological anomalies were observed: spinal curvatures (A) and bodies bent in the shape of the letter C. One day after hatching, the larvae were an average of 8.59 mm long, the surface area of the body was 6.6 mm2 while that of the yolk sac was approximately 1.6 mm2.
The comparison of out-off-season spawning of two cultured ide stock were examined. The obtained results show, that is possible to reproduced ide a few months before their natural spawning season. Generally, the percentage of spermiation and ovulation was very high, as well as spawners survival. The biological quality of the gametes was higher in stock cultured at ponds, than from fish cultured under controlled conditions. One ide females from cultured stock under controlled conditions ovulated without hormonal stimulation (control group). The quality of oocytes collected from this fish was much lower than from hormonally stimulated fish.
The present paper describes the results of induction spermiation and ovulation of ide (Leuciscus idus L.) during and out of spawning season using CPE with addition of hCG, hCG and ovopel - GnRH containing pellets. Males from control group produced significantly smaller volume of milt (season) than those from hormonally treated groups. Significant differences in spermatozoa motility was noted between treated and control males. The percent of ovulated females from groups treated with CPE and ovopel was 100%. Fish from control groups and treated with hCG did not ovulate. The total spawners mortality was quite high, especially in fish treated with ovopel. Generally, all recorded parameters in out of spawning season were lower than those obtained during artificial propagation in natural spawning time.
The aim of the study was to compare the effectiveness of hormonal stimulation of the female ide (Leuciscus idus L.), following the application of two commercial preparations concerning different GnRHa combined with dopamine inhibitors: Ovopel and Ovaprim. Ide spawners were bred under controlled conditions. The examined parameters included the percentage of ovulating females, time of ovulation and the rate of embryo survival to the eyed-egg stage. The growth and survival rates for larvae produced by farm and wild fish were compared. Stimulation with Ovopel resulted in a shorter latency time (36), whereas stimulation with Ovaprim resulted in a higher percentage of live embryos at the eyed-egg stage (79.7 %). Eggs was obtained from 20% of females in the control group, whereas in treated groups it was at level 90–100%. No differences were found between the growth rate of the ide larvae produced by the farm fish and that obtained from wild fish.
The morphogenesis of the digestive tract and swim bladder of ide Leuciscus idus (L.) was analyzed using histopathological methods. At the moment of hatching, ide larvae are more advanced in their development than the larvae of other teleost fish species. Endo-exogenous nutrition began on day 2 post hatch. At this stage of development, the intestine was lined with a single-layered cylindrical epithelium, and both liver and pancreas began to function. Signs of digestion and enterocyte protein and lipid absorption were observed on day 6 of development. The mucus cells in the mouth, esophagus and gullet produced neutral and acidic mucins. Intestinal cuboid cells appeared on the fourth day and only began secreting acidic carboxyl and sulfate mucins. The differentiation of the air duct and the posterior chamber of the swim bladder was observed on the day of hatching, and the bladder inflated after 24 hours. The anterior chamber began to form on day 9, and it inflated with gas between days 23 and 25 of larval development.
In the course of ichthyological inventory investigations in the main watercourse of the Narew River the occurrence of Tracheliastes polycolpus Nordm. Was recorded on ide Leuciscus idus (L.) and pike Esox lucius L. A comparison of the occurrence of this parasite in other rivers of Poland is presented.
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