191 research outputs found

    Elevated sea temperature combined with dietary methionine levels affect feed intake and appetite-related neuropeptide expression in the brains of juvenile cobia (Rachycentron canadum)

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    This study aimed to determine the impact of elevated temperature combined with different levels of dietary methionine concentrations on feed intake (FI) and brain expression of selected neuropeptides and one receptor involved in appetite control in juvenile cobia (approximately 3.7 g body weight). The genes studies were neuropeptide y, npy; agouti-related protein, agrp; cocaine- and amphetamine-regulated transcript, cart; cholecystokinin, cck and melanocortin 4 receptor; mc4r. The cobia were reared at typical sea water temperature in Vietnam (30 degrees C) and elevated temperature (34 degrees C; selected as one of the predicted scenarios of climate change). The fish were fed diets with different levels of methionine: deficient (M9; 9.1 g/kg), sufficient (M12; 12.8 g/kg) and surplus (M16, 16.8 g/kg) for 6 weeks (triplicate tanks per treatment). Both dietary methionine concentration and temperature affected FI in cobia. Dietary methionine deficiency (i.e., M9) and elevated temperature reduced FI in cobia. Temperature significantly influenced the mRNA expression of agrp, cart, cck and mc4r. Expression of the orexigenic neuropeptide npy was consistently higher before the meal than after the meal for all diets and at both temperatures. At 30 degrees C, prefeeding levels of npy correlated with both increased methionine levels and FI. The interaction between dietary methionine and temperature on the levels of brain npy expression was significant (P<0.05). There was higher brain expression of agrp, cart and cck in cobia at 34 degrees C than in fish at 30 degrees C, which was correlated with a lower FI. In conclusion, both feeding, temperature and/or dietary methionine levels affected the brain expression of npy and agrp, cart, cck and mc4r. This suggests that these neuropeptides as well as the mc4r receptor are actively involved in adjusting feed intake to compensate for changing energetic demands, as well as metabolic adjustments due to the variable availability of methionine at elevated temperature.LA/P/0101/2020; QZA-0485 SRV-13/0010info:eu-repo/semantics/publishedVersio

    Effect of increased rearing temperature on digestive function in cobia early juvenile

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    The present study is focused to elucidate the main characteristics of the digestive function of this carnivorous fast-growing fish living at high temperatures. With this aim, we have examined the effects of an increased temperature from 30 to 34 °C on the daily pattern of gastrointestinal pH, enzymatic proteolytic digestive activity and the feed transit time in early juveniles of cobia (Rachycentron canadum), a species living in tropical and subtropical waters with an increasing aquaculture production. Fish were fed two meals a day. Gastric luminal pH was permanently acidic (mean pH values: 2.76-4.74) while the intestinal pH increased from neutral/slightly acidic to slightly alkaline when the digesta was present, with an increasing alkalinity from proximal to distal intestine (mean pH values: 6.05 to 7.69). The temperature did not affect the gastric pH but a slightly higher acidity was induced in the intestine at 34 °C. Pepsin activity showed a daily rhythm at 30 °C with maximum in the middle of the light period, while at 34 °C some hourly changes coinciding with feed adding without a clear daily trend during the 24-h period were observed. The trypsin activity exhibited a daily rhythm at both temperatures with an increase after morning feeding to reach a maximum several hours later. Average pepsin activity during the daily cycle was slightly higher at 34 °C (6.1 and 7.3 U mg-1 BW at 30 and 34 °C respectively), but values were significantly different only at 8 and 24 h after the morning meal. Similarly, the trypsin activity was significantly affected by the temperature only at 8 and 16 h after the morning meal, but daily activity averages were similar (1.20 and 1.29 U g-1 BW at 30 and 34 °C respectively). The partial transit rates of the first meal in the stomach for each period inter-samplings were higher during the first 4-h period and decreased progressively along the rest of the 24-h cycle at both temperatures, but no significant differences were detected at 30 °C. In addition, the transit was notably faster at 34 °C particularly during the first 8 h after feeding, with rates between 100 and 65% of total volume displaced (intake or released) during each 4-h period. In the intestine the transit rate was relatively constant and similar at both temperatures during 12 h after feeding. Then the rates remained very low during the following 12 h. Residence time of the first meal was longer at 30 than at 34 °C, particularly in the stomach (12 h:02 min vs 4 h:54 min respectively). In the intestine the difference was not so large (8 h:18 min vs 6 h:24 min respectively). In a parallel study under same conditions, cobia reared at 30 °C grew faster and showed a more favorable feed conversion ratio than those at elevated temperature (34 °C). The present results indicate that at 34 °C, a subtle increase of proteolytic activity cannot compensate for the faster gut transit rate. Therefore, 30 °C is more appropriate temperature for the early on-growing of cobia because at higher temperatures the digestion efficiency decrease being one of the causes for a lower growth.Agência financiadora European Union (EU) 691150 MINECO, Spain + FEDER/ERDF contribution EFISHDIGESTAGL2014-52888 European Social Fund, the Operational Programme Human Potential IF/00482/2014/CP1217/CT0005 Portuguese Foundation for Science and Technology Portuguese Foundation for Science and Technology UDI/Multi/04326/2013 Norwegian Agency for Development Cooperation NORHED QZA-0485 SRV-13/0010info:eu-repo/semantics/publishedVersio

    The path towards a professional identity: An IPA study of Greek family therapy trainees

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    Objective: Contemporary psychotherapy research has focused mainly on practitioners' training and education. The impact of training on professional development and the application of therapeutic skills have been the primary foci of the empirical literature. The aim of this paper is to present the experiences of seven family therapy trainees regarding their personal paths toward the development of professional identity as they underwent training in systemic psychotherapy. Method: In-depth interviews were conducted and analysed using Interpretative Phenomenological Analysis. Results & Conclusions: Seven themes were identified: The Quest, Developing by Relating, Learnings, Personification of Training, Use of Self, Self-Care and Empowerment, and Reflecting on the Role of the Therapist. The findings are discussed with regard to the development of the 'therapist as a person', gaining acknowledgement and autonomy, and the development of a community of therapeutic practice. © 2013 British Association for Counselling and Psychotherapy

    Cloning, tissue and ontogenetic expression of the taurine transporter in the flatfish Senegalese sole (Solea senegalensis)

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    Flatfish species seem to require dietary taurine for normal growth and development. Although dietary taurine supplementation has been recommended for flatfish, little is known about the mechanisms of taurine absorption in the digestive tract of flatfish throughout ontogeny. This study described the cloning and ontogenetic expression of the taurine transporter (TauT) in the flatfish Senegalese sole (Solea senegalensis). Results showed a high similarity between TauT in Senegalese sole and other vertebrates, but a change in TauT amino acid sequences indicates that taurine transport may differ between mammals and fish, reptiles or birds. Moreover, results showed that Senegalese sole metamorphosis is an important developmental trigger to promote taurine transport in larvae, especially in muscle tissues, which may be important for larval growth. Results also indicated that the capacity to uptake dietary taurine in the digestive tract is already established in larvae at the onset of metamorphosis. In Senegalese sole juveniles, TauT expression was highest in brain, heart and eye. These are organs where taurine is usually found in high concentrations and is believed to play important biological roles. In the digestive tract of juveniles, TauT was more expressed in stomach and hindgut, indicating that dietary taurine is quickly absorbed when digestion begins and taurine endogenously used for bile salt conjugation may be recycled at the posterior end of the digestive tract. Therefore, these results suggest an enterohepatic recycling pathway for taurine in Senegalese sole, a process that may be important for maintenance of the taurine body levels in flatfish species

    Avanços recentes em nutrição de larvas de peixes

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    Os requisitos nutricionais de larvas de peixes são ainda mal compreendidos, o que leva a altas mortalidades e problemas de qualidade no seu cultivo. Este trabalho pretende fazer uma revisão de novas metodologias de investigação, tais como estudos com marcadores, genómica populacional, programação nutricional, génomica e proteómica funcionais, e fornecer ainda alguns exemplos das utilizações presentes e perspectivas futuras em estudos de nutrição de larvas de peixes

    Dietary Essential Amino Acids Affect the Reproduction of the Keystone Herbivore Daphnia pulex

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    Recent studies have indicated that nitrogen availability can be an important determinant of primary production in freshwater lakes and that herbivore growth can be limited by low dietary nitrogen availability. Furthermore, a lack of specific essential nitrogenous biochemicals (such as essential amino acids) might be another important constraint on the fitness of consumers. This might be of particular importance for cladoceran zooplankton, which can switch between two alternative reproductive strategies – the production of subitaneously developing and resting eggs. Here, we hypothesize that both the somatic growth and the type of reproduction of the aquatic keystone herbivore Daphnia is limited by the availability of specific essential amino acids in the diet. In laboratory experiments, we investigated this hypothesis by feeding a high quality phytoplankton organism (Cryptomonas) and a green alga of moderate nutritional quality (Chlamydomonas) to a clone of Daphnia pulex with and without the addition of essential amino acids. The somatic growth of D. pulex differed between the algae of different nutritional quality, but not dependent on the addition of dissolved amino acids. However, in reproduction experiments, where moderate crowding conditions at saturating food quantities were applied, addition of the essential amino acids arginine and histidine (but not lysine and threonine) increased the total number and the developmental stage of subitaneous eggs. While D. pulex did not produce resting eggs on Cryptomonas, relatively high numbers of resting eggs were released on Chlamydomonas. When arginine and histidine were added to the green algal diet, the production of resting eggs was effectively suppressed. This demonstrates the high, but previously overlooked importance of single essential amino acids for the reproductive strategy of the aquatic keystone herbivore Daphnia

    The impact of dietary supplementation with astaxanthin on egg quality in Atlantic cod broodstock (Gadus morhua, L.)

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    This study investigated the effect on egg quality of dietary supplementation of Atlantic cod broodstock with the carotenoid astaxanthin (ASTA). Duplicate groups of farm-reared Atlantic cod broodstock were fed either a control diet with no added ASTA, or an ASTA supplemented diet (73.7 mg/kg dry weight; Carophyll Pink®) for 2 months prior to peak spawning. The results indicated that ASTA uptake into eggs from the broodstock diet was highly efficient. Fish fed the diet supplemented with ASTA produced fewer batches of eggs, but the mean number per batch of eggs spawned/kg female was higher, and numbers of floating eggs and numbers of fertilised eggs per kg female in each batch were also significantly improved. A correlation between the egg ASTA content and fertilisation success of individual batches was identified. This improvement in egg quality demonstrated the potential value of ASTA supplementation of broodstock diets for cod. ASTA supplementation produced a 20% increase in the number of eggs per batch spawned, a 37% increase in the number per batch of floating eggs per kg female and a 47% increase in the number per batch of fertilised eggs per kg female. These results clearly demonstrate significant benefits of ASTA supplementation of cod broodstock feeds in terms of improved egg quality and larval production

    Trends in Epidemiology of Neonatal Sepsis in a Tertiary Center in Korea: A 26-Year Longitudinal Analysis, 1980-2005

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    There were many reports of longitudinal changes in the causative organisms of neonatal sepsis in Western countries but few in Asia. We aimed to study longitudinal trends in the epidemiology of neonatal sepsis at Seoul National University Children's Hospital (SNUCH), a tertiary center in Korea, and compared the results to previous studies of Western countries. The medical records of all of the neonates who were hospitalized at SNUCH from 1996 to 2005 with positive blood cultures were reviewed. We also compared the findings to previous 16-yr (1980-1995). One hundred and forty-nine organisms were identified in 147 episodes from 134 infants. In comparison with the previous 16-yr studies, there was a decrease in the number of Escherichia coli infections (16.2% vs 8.7%: odds ratio [OR] 0.495; 95% confidence interval [CI], 0.255-0.962; P = 0.035), but an increase in Staphylococcus aureus (16.6% vs 25.5%: OR 1.720; 95% CI, 1.043-2.839; P = 0.033) and fungal infections (3.3% vs 18.7%: OR 6.740; 95% CI, 2.981-15.239; P < 0.001), predominantly caused by Candida species. In conclusion, the incidence of sepsis caused by E. coli decreases, but S. aureus and fungal sepsis increases significantly. Compared with Western studies, the incidence of sepsis caused by S. aureus and fungus has remarkably increased

    The effects of a 6-week strength training on critical velocity, anaerobic running distance, 30-m sprint and yo-yo intermittent running test performances in male soccer players

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    The objectives of this study were to examine the effects of a moderate intensity strength training on changes in critical velocity (CV), anaerobic running distance (D'), sprint performance and Yo-Yo intermittent running test (Yo-Yo IR1) performances. Methods: two recreational soccer teams were divided in a soccer training only group (SO; n = 13) and a strength and soccer training group (ST; n = 13). Both groups were tested for values of CV, D', Yo-Yo IR1 distance and 30-m sprint time on two separate occasions (pre and post intervention). The ST group performed a concurrent 6-week upper and lower body strength and soccer training, whilst the SO group performed a soccer only training. Results: after the re-test of all variables, the ST demonstrated significant improvements for both, YoYo IR1 distance (p = 0.002) and CV values (p<0.001) with no significant changes in the SO group. 30-m sprint performance were slightly improved in the ST group with significantly decreased performance times identified in the SO group (p<0.001). Values for D' were slightly reduced in both groups (ST -44.5 m, 95% CI = -90.6 to 1.6; SO -42.6 m, 95% CI = -88.7 to 3.5). Conclusions: combining a 6-week moderate strength training with soccer training significantly improves CV, Yo-Yo IR1 whilst moderately improving 30-m sprint performances in non-previously resistance trained male soccer players. Critical Velocity can be recommended to coaches as an additional valid testing tool in soccer

    Vertebrate Vitellogenin Gene Duplication in Relation to the “3R Hypothesis”: Correlation to the Pelagic Egg and the Oceanic Radiation of Teleosts

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    The spiny ray-finned teleost fishes (Acanthomorpha) are the most successful group of vertebrates in terms of species diversity. Their meteoric radiation and speciation in the oceans during the late Cretaceous and Eocene epoch is unprecedented in vertebrate history, occurring in one third of the time for similar diversity to appear in the birds and mammals. The success of marine teleosts is even more remarkable considering their long freshwater ancestry, since it implies solving major physiological challenges when freely broadcasting their eggs in the hyper-osmotic conditions of seawater. Most extant marine teleosts spawn highly hydrated pelagic eggs, due to differential proteolysis of vitellogenin (Vtg)-derived yolk proteins. The maturational degradation of Vtg involves depolymerization of mainly the lipovitellin heavy chain (LvH) of one form of Vtg to generate a large pool of free amino acids (FAA 150–200 mM). This organic osmolyte pool drives hydration of the ooctye while still protected within the maternal ovary. In the present contribution, we have used Bayesian analysis to examine the evolution of vertebrate Vtg genes in relation to the “3R hypothesis” of whole genome duplication (WGD) and the functional end points of LvH degradation during oocyte maturation. We find that teleost Vtgs have experienced a post-R3 lineage-specific gene duplication to form paralogous clusters that correlate to the pelagic and benthic character of the eggs. Neo-functionalization allowed one paralogue to be proteolyzed to FAA driving hydration of the maturing oocytes, which pre-adapts them to the marine environment and causes them to float. The timing of these events matches the appearance of the Acanthomorpha in the fossil record. We discuss the significance of these adaptations in relation to ancestral physiological features, and propose that the neo-functionalization of duplicated Vtg genes was a key event in the evolution and success of the teleosts in the oceanic environment
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