Manipulation of the Seasonal Reproductive Cycle of the Landlocked Atlantic Salmon (Salmo salar) by LHRH Analogues Administered at Various Stages of Gonadal Development

1983 ◽  
Vol 40 (1) ◽  
pp. 61-67 ◽  
Author(s):  
L. W. Crim ◽  
D. M. Evans ◽  
B. H. Vickery
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Reproductive Cycle ◽  
Gonad Development ◽  
Reproductive Development ◽  
Hormone Treatment ◽  
Gonadal Development ◽  
Rapid Phase ◽  
Atlantic Salmon Salmo Salar ◽  
Lhrh Analogues

Pellets designed for continuous, long-term, oligopeptide, hormone delivery were implanted into the adult landlocked Atlantic salmon (Salmo salar) to investigate the effects of LHRH agonist analogue (LHRH-A) upon the reproductive system. Chronic elevations in plasma gonadotropin were observed in experimental fish at a variety of stages of reproductive development. Synthesis of pituitary gonadotropin was also evoked in sexually regressed fish and fish undergoing gonadal recrudescence, but the already elevated level of pituitary GtH observed in prespawning and spawning salmon was not augmented. In prespawning fish, the events of ovulation and spermiation were accelerated by LHRH-A treatment. The LHRH-A hormone treatment also increased milt volume and the duration of spermiation in ripe males. In sexually regressed males LHRH-A treatment did not induce the advanced phases of spermatogenesis but some testicular stimulation was indicated by the presence of increased numbers of B-type spermatogonia and enlargement of the lumen of lobules. The gonadal response to LHRH-A treatment during the rapid phase of gonad recrudescence differed in males and females. Based upon the changes in GSI, the LHRH analogue accelerated vitellogenic development of the ovaries in females; in males, however, the GSI was significantly reduced following LHRH-A administration. Whereas, it seems clear that a long acting preparation containing LHRH-A can be successfully used in prespawning fishes to advance the final events of gonadal maturation and initiate spawning, further studies are necessary to evaluate the potential of LHRH agonists to either stimulate or inhibit the reproductive development of fish at other stages of the seasonal reproductive cycle.Key words: fish, teleosts, landlocked salmon, LHRH analogues, gonadotropic hormone releasing hormones, seasonal reproductive cycle, gonad development, spawning

The effect of porcine somatotropin on growth, and survival in seawater of Atlantic salmon (Salmo salar) parr

1976 ◽  
Vol 54 (4) ◽  
pp. 531-535 ◽  
Author(s):  
M. P. Komourdjian ◽  
R. L. Saunders ◽  
J. C. Fenwick
Keyword(s):  
Growth Hormone ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth Hormone Treatment ◽  
Hormone Treatment ◽  
Control Fish ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Porcine Somatotropin

The effects of porcine growth hormone on growth and salinity tolerance were studied in Atlantic salmon (Salmo salar) parr. Fish were held in freshwater at 11.5 °C during June and July under a photoperiod with light to dark periods opposite to the prevailing natural conditions. Fish treated with 1.0 μg/g body weight of growth hormone preparation on alternate days were significantly longer (P <.05), after 4 weeks, than placebo-injected controls. All hormone-injected fish survived transfer to seawater, 30‰ salinity. But under the same conditions, placebo-injected control fish showed a high mortality rate. Growth-hormone treatment caused a darkening of fin margins and a yellowing of the operculae and fin surfaces. The silvering which normally accompanies smoltification was not observed. The role of growth hormone in eliciting these actions and its possible role in the parr–smolt transformation are discussed.

Determination of Sexual Maturation Stages of Atlantic Salmon (Salmo salar) Captured at Sea

1981 ◽  
Vol 38 (4) ◽  
pp. 405-413 ◽  
Author(s):  
D. R. Idler ◽  
S. J. Hwang ◽  
L. W. Crim ◽  
D. Reddin
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Gonadosomatic Index ◽  
Gonadal Development ◽  
Maturation Stage ◽  
Female Fish ◽  
Histological Techniques ◽  
Atlantic Salmon Salmo Salar ◽  
Placentia Bay

Radioimmunoassay (RIA) of plasma vitellogenin (Vg), estradiol (E2), 11-ketotestosterone (11-keto), and gonadotropin (GtH), together with histological techniques were evaluated for determination of the maturation stage of Atlantic salmon (Salmo salar) at sea.Male salmon had lower plasma Vg, E2, and higher 11-keto levels and could be distinguished from females several months in advance of spawning. Six female salmon were tagged at sea in 1975 in Placentia Bay and samples of blood taken. When the fish were recovered in rivers the lowest plasma Vg value was 396 μg/mL. This formed the basis of a working hypothesis, that fish with Vg values in excess of 396 μg/mL (~5–6 mo before spawning) will spawn in the year of capture. This hypothesis was supported by the Vg values of an additional 19 tagged females recaptured in Newfoundland and mainland rivers and brackish water off mainland rivers in 1976.Significant correlations between stage of gonadal development and plasma Vg, stage of gonadal development and gonadosomatic index (GSI), stage of gonadal development and plasma E2, plasma Vg and plasma E2, GSI and plasma E2, and between plasma Vg and 11-keto values were found for the female fish. The gonadal development of female fish from Bonavista Bay ranged between oil globule stage and secondary yolk stage. All those females which had reached the primary yolk stage would almost certainly mature and may be considered spawners of the year; on this basis 91% of the females were spawners of the year. Based on the minimum plasma Vg values, at sea, for fish which subsequently returned to the rivers, there were 86% spawners of the year among female salmon taken in Bonavista Bay. Based on plasma Vg levels, spawners of the year ranged from essentially zero in Greenland (fish captured in Greenland during August–November are not spawners of the year, except for the very few that spawn in one Greenland river) to 100% for fish caught in several other fisheries.11-Ketotestosterone was higher in the male fish than in the female fish and there was a correlation between GSI and 11-keto for male fish.The plasma GtH content of fish taken in the sea was extremely low as measured by RIA.Key words: salmon, maturation, migration, radioimmunoassay, vitellogenin, estradiol, gonadotropin, 11-ketotestosterone, histology, gonadosomatic index

scholarly journals Heterogenic origin of micro RNAs in Atlantic salmon (Salmo salar) seminal plasma

2019 ◽  
Author(s):  
Teshome Tilahun Bizuayehu ◽  
Igor Babiak
Keyword(s):  
Atlantic Salmon ◽  
Blood Plasma ◽  
Salmo Salar ◽  
Seminal Plasma ◽  
Somatic Cells ◽  
Gonadal Development ◽  
P Value ◽  
Atlantic Salmon Salmo Salar ◽  
Micro Rnas ◽  
Regulatory Functions

Abstract Background The origin and contribution of seminal plasma RNAs into the whole semen RNA repertoire are poorly known, frequently being overlooked or neglected. Virtually nothing is known about seminal plasma RNAs in fish, including small RNAs, which have regulatory functions in gonadal development. Results In this study, we profiled microRNA (miRNA) constituents in the whole semen, as well as in fractionated spermatozoa and seminal plasma of Atlantic salmon (Salmo salar). Among 306 conserved miRNAs, 85 were differentially accumulated (>2 log-fold change and p-value < 0.01) between spermatozoa and the seminal plasma. We identified a number of seminal plasma-enriched and spermatozoa-enriched miRNAs. We localized the expression of some miRNAs in juvenile and mature testes. Two abundant miRNAs, miR-92a-3p and miR-202-5p, localized to both spermatogonia and somatic supporting cells in immature testis, and they were also highly abundant in somatic cells in mature testis. miR-15c-5p, miR-30d-5p, miR-93a-5p, and miR-730-5p were detected only in mature testis. miRs 92a-3p, 202-5p, 15c-5p, and 30d-5p were detected also in a juvenile ovary in locations corresponding to these from the testis. Additional RT-qPCR experiment demonstrated lack of correlation in miRNA transcript levels in seminal plasma versus blood plasma. Conclusions Our results indicate that salmon semen is rich in miRNAs, which are present in both spermatozoa and seminal plasma. The latter ones have partially different profile indicating their heterogenic origin. Testicular supporting somatic cells are likely the source of seminal plasma enrichment, whereas blood plasma unlikely contributes to the seminal plasma miRNA repertoire.

Energy allocation among developmental stages, age groups, and types of Atlantic salmon (Salmo salar) spawners

2003 ◽  
Vol 60 (5) ◽  
pp. 506-516 ◽  
Author(s):  
Nina Jonsson ◽  
Bror Jonsson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Developmental Stages ◽  
Energy Content ◽  
Energy Allocation ◽  
Gonadal Development ◽  
Power Functions ◽  
Allocation Pattern ◽  
Atlantic Salmon Salmo Salar ◽  
Mature Parr

Relationships between energy density (kJ·100 g–1) and body length (mm), which varied between life-history stages of Atlantic salmon (Salmo salar), were described by power functions. The variation was chiefly caused by differences in lipid concentrations. Energy densities of maturing and rematuring parr were higher than those of similarly aged smolts. Monthly specific growth rate was higher in maturing parr than in salmon at sea. Mature parr males allocated relatively more energy to gonadal development and less to soma development than anadromous males. Spawning expenditure increased from 34 to 53% for 55- to 72-cm-long females. In males, similar losses were from 47 to 49% of their total energy content at river entry. More energy was used in reproduction in a long river than in a short one. Male allocation to gonads relative to soma was highest in the shorter river. Energy allocation pattern varied among developmental stages. Very energy-rich male parr rematured in subsequent years without going to sea; less energy-rich ones smolted and migrated to sea.

Quantification of Vitellogenin in Atlantic Salmon (Salmo salar) Plasma by Radioimmunoassay

1979 ◽  
Vol 36 (5) ◽  
pp. 574-578 ◽  
Author(s):  
D. R. Idler ◽  
S. J. Hwang ◽  
L. W. Crim
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Weight Fraction ◽  
Egg Yolk ◽  
Gonadal Development ◽  
Low Molecular Weight ◽  
Plasma Samples ◽  
Yolk Proteins ◽  
Atlantic Salmon Salmo Salar ◽  
Standard Solution

An antibody prepared against salmon egg yolk proteins has been used to quantify Atlantic salmon (Salmo salar) plasma vitellogenin using radioimmunoassay. A low molecular weight fraction isolated from salmon egg yolk was used for radioiodination and as standard solution because plasma vitellogenin could not be iodinated successfully. Parallelism of the egg yolk standard to displacement given by a fraction isolated from vitellogenic salmon plasma and dilutions of plasma samples allowed the assay to be used to evaluate the state of gonadal development of migrating females several months in advance of spawning and for sexing relatively immature salmon. Key words: salmon, plasma vitellogenin; vitellogenin, quantification in salmon plasma; radioimmunoassay, salmon vitellogenin

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