Broodstock Management (broodstock + management)

Distribution by Scientific Domains
Earth and Environmental Science100%

Selected Abstracts

Cryopreservation of fish sperm: applications and perspectives

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2010
E. Cabrita
Summary Cryopreservation is of interest not only for fish farming but also for the conservation and genetic improvement of resources. This technique has been well established in some freshwater fish species mainly, salmonid, sturgeons and carps, however, only in the last decade research was focused in marine fish species. The benefits of sperm cryopreservation include: (i) synchronization of gamete availability of both sexes, (ii) sperm economy; (iii) simplification of broodstock management, (iv) transport of gametes from different fish farms, and (v) germplasm storage for genetic selection programs or conservation of species. These issues would certainly benefit the aquaculture industry. The tremendous impact that biotechnology is having in aquaculture has been particularly obvious in recent years. Several species are being used as research models not only for aquaculture development applications but also for medical research. Sperm cryopreservation can give an important contribution in the germ storage of all transgenic lines. However, in all applications in fish sperm, cryopreservation needs to overcome a lack in standardization of methodologies and procedures, a correct assay of seminal quality and the development of tools to characterize cryoinjury. Many efforts have recently been made in the study of DNA using different approaches such as the comet assay (single cell gel electrophoresis), TUNEL (terminal deoxynucleotidyl transferase-nick-end-labelling), SCSA (sperm chromatin structure assay) and the analysis of specific DNA sequences using RT-PCR, since DNA damage may impair fertility or embryo development. Cryopreservation of gametes would certainly benefit from a higher concern on male improvement, basically through nutrition or selection of resistant stocks (e.g. stress resistant individuals or highly adapted to captivity) producing gametes of higher quality. There is a huge window of opportunities for improve the resistance of cells to cryopreservation through diet supplementation of certain compounds such as amino acids (taurine and hypotaurine), vitamins (Vit. E and C) and lipids or through a direct supplementation of the extender media. An equilibrium of those compounds will improve spermatozoa and seminal plasma composition protecting cells against oxidative stress (lipid peroxidation, protein oxidation, DNA fragmentation, enzyme protection) that is gaining each day more importance in cryodamage research. [source]

A rapid latex agglutination test for gender identification in the Atlantic bluefin tuna, Thunnus thynnus (Linnaeus)

AQUACULTURE RESEARCH, Issue 9 2010
Elisabetta Micera
Abstract A rapid, one-step agglutination assay has been developed, based on latex particles sensitized with antibodies against vitellogenin (Vtg), aimed at Atlantic bluefin tuna, Thunnus thynnus (Linnaeus) (ABFT), gender identification. The egg-yolk precursor protein Vtg was used as a gender marker for the assay as it is a female-specific protein synthesized during reproductive maturation. The presence of Vtg in the plasma was revealed in 60,120 s through an agglutination reaction by mixing small volumes of ABFT plasma and an anti-Vtg antibody-latex suspension on a microscope slide. The effectiveness of the present test was restricted to the months of May and June, concomitant with high circulating Vtg levels. Because of its rapidity and ease of performance in the field, the present gender identification assay could be useful for broodstock management in the aquaculture industry as well as in tagging studies on wild populations. [source]

Statistical properties and performance of pairwise relatedness estimators using turbot (Scophthalmus maximus L.) family data

AQUACULTURE RESEARCH, Issue 4 2010
Ania Pino-Querido
Abstract The statistical properties and performance of four estimators of pairwise relatedness were evaluated in several scenarios using the microsatellite genotype data from a set of large known full-sibships of turbot. All estimators showed a significant negative bias for the four kinships commonly used in these studies (unrelated: UR, half-sibs, full-sibs and parent,offspring), when allele frequencies of the reference population were estimated from the individuals analysed. When these frequencies were obtained from the base population from which all families proceeded, the bias was mostly corrected. The Wang (W) and Li (L) estimators were the least sensitive to this factor, while the Lynch and Ritland (L&R estimator) was the highest one. The error (mean around 0.130) was very similar in all scenarios for W, L and Queller and Goodnight (QG) estimators, while L&R was the highest error-prone estimator. Parent,offspring kinship resulted in the lowest error, when using W, L and QG estimators, while UR resulted in the lowest error with the L&R estimator. Globally, W was the best-performing estimator, although L&R could perform better in specific sampling scenarios. In summary, pairwise estimators represent useful tools for kinship classification in aquaculture broodstock management by applying appropriate thresholds depending on the goals of the analysis. [source]

Ovarian maturation stages of the mud crab Scylla serrata

AQUACULTURE RESEARCH, Issue 14 2007
Emilia T Quinitio
Abstract Ovarian maturation in adult wild-sourced and pond-grown Scylla serrata (Forsskål) was determined based on gross morphology and histological appearance. There were no significant differences noted in the histological features of both wild and pond-reared S. serrata females. Ovarian maturation was classified into five stages: immature, early maturing, late maturing, fully mature and spent. The immature ovaries are thin and translucent to off white and contain oogonia, primary oocytes with large nuclei. The follicle cells were found around the periphery of the lobes and an area among groups of oogonia and oocytes. The follicle cells gradually enclosed the oocytes. The early-maturing ovaries were yellow and small yolk globules started to appear in larger oocytes. In late-maturing ovaries, the colour became light orange and lobules were apparent. Yolk globules occurred in the cytoplasm with larger globular inclusions towards the periphery, while follicle cells were hardly recognizable. Fully mature ovaries were orange to deep orange and had swollen lobules. Large yolk globules were apparent in the entire cytoplasm. Follicle cells were hardly seen. Spent ovaries were similar to the early-maturing and late-maturing stage in partially spawned females. The ovarian development was correlated closely to the gonadosomatic index, oocyte diameter, and ovarian histology. The classification of ovarian maturation provides baseline information for further studies on reproductive biology. Likewise, the information provides a guide for broodstock management in the hatchery. [source]