Nutrition of greater amberjack (Seriola dumerili): Highlights at different stages of the life cycle.

DIVERSIF

Rapid generation of long synthetic tandem repeats and its application for analysis in human artificial chromosome formation

Human artificial chromosomes (HACs) provide a unique opportunity to study kinetochore formation and to develop a new generation of vectors with potential in gene therapy. An investigation into the structural and the functional relationship in centromeric tandem repeats in HACs requires the ability to manipulate repeat substructure efficiently. We describe here a new method to rapidly amplify human alphoid tandem repeats of a few hundred base pairs into long DNA arrays up to 120 kb. The method includes rolling-circle amplification (RCA) of repeats in vitro and assembly of the RCA products by in vivo recombination in yeast. The synthetic arrays are competent in HAC formation when transformed into human cells. As short multimers can be easily modified before amplification, this new technique can identify repeat monomer regions critical for kinetochore seeding. The method may have more general application in elucidating the role of other tandem repeats in chromosome organization and dynamics

Dietary tuna hydrolysate modulates growth performance, immune response, intestinal morphology and resistance to Streptococcus iniae in juvenile barramundi, Lates calcarifer

This study investigated the effects of tuna hydrolysate (TH) inclusion in fishmeal (FM) based diets on the growth performance, innate immune response, intestinal health and resistance to Streptococcus iniae infection in juvenile barramundi, Lates calcarifer. Five isonitrogenous and isoenergetic experimental diets were prepared with TH, replacing FM at levels of 0% (control) 5%, 10%, 15% and 20%, and fed fish to apparent satiation three times daily for 8 weeks. The results showed that fish fed diets containing 5% and 10% TH had significantly higher final body weight and specific growth rate than the control. A significant reduction in blood glucose was found in fish fed 10%, 15% and 20% TH compared to those in the control whereas none of the other measured blood and serum indices were influenced by TH inclusion. Histological observation revealed a significant enhancement in goblet cell numbers in distal intestine of fish fed 5 to 10% TH in the diet. Moreover, fish fed 10% TH exhibited the highest resistance against Streptococcus iniae infection during a bacterial challenge trial. These findings therefore demonstrate that the replacement of 5 to 10% FM with TH improves growth, immune response, intestinal health and disease resistance in juvenile barramundi

Effects of inclusion of yeast and pig blood protein hydrolysates in microdiets on larval quality of gilthead sea bream Sparus aurata

International audienc

Peptide molecular weight, distribution of soluble protein fraction affects growth performance and quality in European sea bass (Dicentracrchus labrax) larvae

International audienceDicentrarchus labrax were fed from 10 to 40days posthatching with six microdiets differing in the inclusion level (60gkg(-1) and 120gkg(-1)) and type of protein hydrolysate (PH; yeast, YPH; pig blood, PBPH; pig red blood cells, PRBCPH). A microdiet containing 120gkg(-1) fish PH (FPH) was used as a control. PH differed in their amino acid (AA) profile and molecular weight distribution and therefore the tested microdiets too. The estimated content in FAA and di- and tripeptides in the FPH microdiet was 2gkg(-1) and 44gkg(-1), respectively. FAA estimated levels in YPH and PBPH microdiets were 26gkg(-1) and 53gkg(-1), whereas levels of di- and tripeptides were 30gkg(-1) and 60gkg(-1), respectively. The estimated levels of FAA in PRBCPH microdiets were 8gkg(-1) and 17gkg(-1), whereas estimated levels of di- and tripeptides were 11gkg(-1) and 22gkg(-1), respectively. Results revealed that FPH may be replaced by alternative PH from yeast and pig blood products, as fish fed those diets performed, in terms of growth, survival, digestive function and incidence of skeletal deformities, as well as those fed the FPH microdiet. Using YPH, PBPH and PRBCPH, the inclusion level of PH in microdiets might be reduced to a half with respect to current practices using FPH

Screening for marine nanoplanktic microalgae from Greek coastal lagoons (Ionian Sea) for use in mariculture

Mediterranean mariculture uses imported strains of marine phytoplankton, raising questions of ecological risk and ability to adapt to local conditions for mass culture outdoors. In this context, we report here on the mass-culture potential and chemical composition of six strains of Prasinophyceae (five strains of Tetraselmis sp. and one Pyramimonas sp.) isolated from a Greek coastal lagoon. Proximate composition had a pattern of 10-20% ash, 35-65% protein, 6-10% lipids, and 25-45% other organics including carbohydrates. The amino acid profiles were typical for the marine representatives of the class. All strains had a high PUFA content with dominant the ω3 fraction in four of them. The fatty acid profiles indicated a Tetraselmis strain with high EPA (14%) and a Pyramimonas strain with high DHA (6%). These strains might be a good alternative for the common commercial strains used in Mediterranean aquaculture. © 2009 Springer Science+Business Media B.V

Isolation, characterization, and sequencing of nodavirus in sturgeon (Acipenser gueldestaedi L.) reared in freshwater facilities

The study demonstrates the presence of a nodavirus that affected sturgeon in fresh water, causing disease with neurological signs. The virus was isolated and inoculated onto SSN-1 (striped snakehead, Channa striatus) cell cultures where cytopathic effects (CPE) of the virus included vacuolation of the cells and degeneration of the monolayer. A 255 bp amplicon from nucleic acid preparations of brain tissue from infected sturgeon was detected by PCR (RT-PCR and nested-PCR) and compared with corresponding amino acid sequences of other infected species. The sequences from the sturgeon were similar to those of sea bass, red spotted grouper, and European eel, supporting the hypothesis that the virus originated in marine fish and was horizontally transmitted to freshwater sturgeon