Biología reproductiva de la alacha (Sardinella aurita) en el Mediterráneo NE

The reproductive biology of round sardinella, Sardinella aurita Valenciennes, 1847, was studied for the first time in the north-eastern Mediterranean Sea. Round sardinella has gained much attention lately because of its biomass increase, which might be the result of climatic changes occurring across the Mediterranean Sea. Monthly samples were collected on board commercial purse-seiners for two complete year cycles (September 2000 to August 2002). Round sardinella is a gonochoristic fish. The overall female to male ratio was not statistically different (P=0.34) from unity, although it varied monthly and with the length of the fish. The seasonal changes in the gonadosomatic index and the macroscopic characteristics of gonads showed that round sardinella in the northern Aegean spawns between May and July. Male round sardinella reach first sexual maturity at a smaller total length than females (155.0 and 168.3 mm respectively). Mean absolute fecundity (FA) increased exponentially with body length (FA=0.0949xL4.22) and weight (FA=511.19xW1.02), with an average of ~21,000 oocytes produced per spawning female. Relative fecundity (FR) ranged between 242 and 681 oocytes/g of body weight (average: 445 oocytes/g). The frequency distribution of oocytes showed that round sardinella produces a single batch of oocytes. In general, the reproductive characteristics of round sardinella in the north-eastern Mediterranean Sea differed when compared to stocks from other areas of its distribution.La biología reproductiva de la alacha, Sardinella aurita Valenciennes, 1847 fue estudiada por primera vez en el Mediterráneo NE. Esta especie ha sido recientemente motivo de atención debido a su incremento de biomasa, que podría ser debido a cambios climáticos en el Mediterráneo. Se obtuvieron muestras mensuales a bordo de barcos de pesca con artes de cerco durante dos ciclos anuales completos (Septiembre de 2000-Agosto de 2002). La alacha es una especie gonocorista. Globalmente, la proporción de sexos no fue estadísticamente (P=0.34) diferente de la unidad. Los cambios estacionales en el índice gonadosomático y en las características macroscópicas de las gónadas mostraron que la época de puesta de la alacha en el norte del mar Egeo tiene lugar entre Mayo y Julio. Los machos de la alacha alcanzaron la madurez sexual a una talla total inferior a la de las hembras (155.0 y 168.3 mm, respectivamente). La fecundidad media absoluta (FA) se incrementó exponencialmente con la talla (FA=0.0949×L4.22) y peso (FA=511.19×W1.02), con una media de ~21,000 oocitos producidos por hembra madura. La fecundidad relativa (FR) osciló entre 242 y 681 oocitos/g de peso corporal (promedio: 445 oocitos/g). La distribución de frecuencias de los oocitos mostró que la alacha produce una única cohorte de oocitos. En general, las carácterísticas reproductivas de la alacha del Mediterráneo NE son distintas de las observadas en poblaciones de otras áreas de su distribución.

Heat shock protein (HSP) expression and mitogen-activated protein kinase (MAPK) phosphorylation during early embryonic developmental stages of the Gilthead sea bream (Sparus aurata)

Both heat shock proteins (HSPs), which have key roles in vital cell functions, as well as members of the mitogen-activated protein kinases (MAPKs), which adjust gene expression by transducing cellular signals to the nucleus, are necessary for normal embryonic development in vertebrates. Therefore, protein expression levels of HSP70 and HSP90 and the activation of members of the MAPK protein family, such as p38 MAPK, ERKs, and JNKs were studied in the early developmental stages of the Gilthead sea bream, Sparus aurata Linnaeus, 1758. The protein expression of HSP70 and the phosphorylation ratio of JNKs remained at equal levels at all examined developmental stages, while the other examined proteins exhibited a differential profile. HSP90 levels were mostly increased at the 16-cell stage and towards the morula stages, and the lowest values were observed at the two- to four-cell and one-half epiboly stages. While p38 MAPK phosphorylation ratio exhibited increased values mostly in the early developmental stages, the opposite was observed concerning ERK phosphorylation ratio, where increased values were observed in the later embryonic stages (high blastula to one-half epiboly stages). These differential profiles of the examined protein expression levels highlight the importance of these proteins during embryogenesis and pave the way for further research to unveil their distinct role in early development

Core vs. diet -associated and postprandial bacterial communities of the rainbow trout (Oncorhynchus mykiss) midgut and feaces

ACKNOWLEDGMENTS: Eleni Mente was awarded a visiting fellowship by Marine Alliance for Science and Technology Scotland (MASTS). Part of Eleni’s Nikouli’s work in this paper was carried out under the program “Scholarships of IKY in the Marine and Inland Management of Water Resources” and was co-funded by EEA grants– Financial Mechanism 2009-2014 (85%) and the General Secretariat for Investments and Development (15%). The authors declare no competing interests.Peer reviewedPublisher PD

Dietary Tenebrio molitor Larvae Meal Inclusion Exerts Tissue-Specific Effects on Cellular, Metabolic, and Antioxidant Status in European Sea Bass (Dicentrarchus labrax) and Gilthead Seabream (Sparus aurata)

The present study addresses the effects of dietary Tenebrio molitor (TM) larvae meal inclusion on cytoprotective, cell death pathways, antioxidant defence, and intermediate metabolism in the heart, muscle, and digestive tract of gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax). Three experimental diets were formulated to contain 0%, 25%, or 50% inclusion TM levels. Heat Shock Proteins (HSPs) induction was apparent in both species’ muscle at 50% inclusion. Conversely, p44/42 Mitogen-Activated Protein Kinase (MAPK) activation was increased () in both species’ muscle and digestive tract at 25% inclusion. Regarding the apoptotic machinery, TM inclusion exerted no influence on gilthead seabream, while suppression through autophagy may have occurred in the muscle. However, significant apoptosis () was evident in European sea bass muscle and digestive tract. Both fish species’ heart seemed to additionally rely on lipids compared to muscle and digestive tract. In contrast to gilthead seabream, European sea bass exhibited increased () antioxidant activity at 50% TM inclusion. The present findings highlight the dietary derived induction of cellular responses in a species- and tissue-specific manner, whereas European sea bass appears to be more susceptible to TM inclusion

Tenebrio molitor larvae meal inclusion affects hepatic proteome and apoptosis and/or autophagy of three farmed fish species

Acknowledgements Financial support for the trial on European sea bass was provided by the AQUAEXEL Project PROINSECTLIFE (Ref. No. 0013/03/05/15B), the AQUAEXEL Project INDIFISH (Ref. No. 0125/08/05/15/TNA), and by the University of Turin (ex 60%) Grant (Es. fn. 2014). NP (Scholarship Code: 1752) has been fnancially supported by the General Secretariat for Research and Technology (GSRT) of Greece and the Hellenic Foundation for Research and Innovation (HFRI) and MM by the Operational Programme “Human Resources Development, Education and Lifelong Learning” in the context of the project “Strengthening Human Resources Research Potential via Doctorate Research” (MIS-5000432) as implemented by the State Scholarships Foundation (ΙΚΥ). Tanks to Evelyn Argo and Craig Pattinson (University of Aberdeen) for providing help with 2DE. EM was fnancially supported by Marine Alliance for Science and Technology Scotland (MASTS) visiting Fellowship.Peer reviewedPublisher PD

Sex-biased dynamics of three-spined stickleback (Gasterosteus aculeatus) gene expression patterns

The study of the differences between sexes presents an excellent model to unravel how phenotypic variation is achieved from a similar genetic background. Sticklebacks are of particular interest since evidence of a heteromorphic chromosome pair has not always been detected. The present study investigated sex-biased mRNA and small non-coding RNA (sncRNA) expression patterns in the brain, adipose tissues, and gonads of the three-spined stickleback. The sncRNA analysis indicated that regulatory functions occurred mainly in the gonads. Alleged miRNA-mRNA interactions were established and a mapping bias of differential expressed transcripts towards chromosome 19 was observed. Key players previously shown to control sex determination and differentiation in other fish species but also genes like gapdh were among the transcripts identified. This is the first report in the three-spined stickleback demonstrating tissue-specific expression comprising both mRNA and sncRNA between sexes, emphasizing the importance of mRNA-miRNA interactions as well as new presumed genes not yet identified to have gender-specific roles