Cold-induced growth arrest in gilthead sea bream Sparus aurata: metabolic reorganisation and recovery

There are currently no standard diets or practices to counteract or ameliorate the growth arrest and extremely poor feed conversion rates (FCR) in gilthead sea bream Sparus aurata caused by low water temperatures. The present study analysed the effects of reducing dietary lipid content from 18 to 14 % during a temperature fluctuation period. Temperature was gradually reduced from 22 degrees to 14 degrees C over a period of 5 d, and maintained at this low temperature for a further 45 d before gradual recovery over 7 d to 22 degrees C under controlled conditions, avoiding other stressors often present in cage culture conditions. Decreasing dietary lipid content at an elevated temperature (22 degrees C) did not significantly affect the standard growth rate or FCRs of the sea bream, indicating a possibility to reduce the dietary energy during the months before winter. Although cold-induced growth arrest and metabolic depression were unavoidable, a well-formulated, low-lipid diet adequately met the low energy demands at low temperatures. Analysis of plasma metabolites and liver enzyme activities demonstrated a reorganisation of liver metabolism, mainly in fish on a low-lipid diet. Recovery from low temperatures was delayed, with a higher dietary lipid content required for optimal liver condition, and mineral supplementation to maintain osmoregulation and bone formation. Our results provide useful information for fish producers and researchers, suggesting that dietary lipid contents should be reduced to allow fish to better cope with low temperatures, and that improved diets with higher lipid content are required for recovery from low temperatures.Spanish government - AGL2011-29873; Erasmus Turkish Programinfo:eu-repo/semantics/publishedVersio

Effects of temperature and substrate on growth and survival of Penaeus semisulcatus (decapoda: Penaeidae) postlarvae

This study was carried out to determine the optimal water temperature and to investigate the effects of additional substrate on growth and survival during the nursery culturing of Penaeus semisulcatus in two separate experiments. At the end of six weeks, survivals of postlarvae (PLs) at 22, 24, 26, 30 and 34°C were 52, 46, 70, 30 and 40%, respectively. The highest (2.76 mm/week) and lowest growth rates in terms of total length (0.43-0.49 mm/week) were displayed by the PLs grown at 34°C and 22-24°C, respectively. Growth rates were 1.75 mm/week at 30°C and 1.03 mm/week at 26°C. Final individual weight showed a drastic increase (over five times) with increasing temperature level from 22°C (55 mg) to 34°C (285 mg). Individual final weights at 22, 24 and 26°C were not significantly different from each other (P>0.05). Weight gain per week was 432 mg/week at 34°C and 58-68 mg/week at 22-24°C. The PLs at 34°C had a growth rate 6-7 times faster than those at 22-24°C. Yield at 34°C (5.7 g) was four times as high as that at 22°C (1.43 g). The yield at 24, 26 and 30°C was 1.40, 3.03 and 2.59 g, respectively. Artificial substrate constructed of seine netting to increase habitat area did not improve the survival and growth of postlarvae compared with the control

Effects of adding salt to the diet of Asian sea bass Lates calcarifer reared in fresh or salt water recirculating tanks, on growth and brush border enzyme activity

The Asian sea bass is a carnivorous, euryhaline species originating in seawater. It is currently being reared under intensive conditions in fresh and brackish water recirculating ponds. The effects of feeding sea bass a diet containing different levels of salt (NaCl) were evaluated in closed recirculating tanks in either fresh or salt (20‰) water rearing conditions. Under freshwater conditions, the addition of salt to the diet resulted in a significant improvement in the feed conversion ratio (FCR), and had no effect on carcass composition of the fish. Under saltwater (20‰) rearing conditions, it had no affect on either growth or FCR. The addition of salt enhanced the activity of the brush border enzymes alkaline phosphatase, lactase, and, to some extent, leucine amino peptidase in fish reared in freshwater, with the most pronounced effect exhibited in the pyloric caeca. The overall activity level of the brush border enzymes of fish reared in saltwater was found to be higher than that of the fish reared in freshwater. Fish reared in saltwater exhibited significant higher enzymatic activity of maltase, sucrase, and ?-glutamyl transpeptidase when fed a diet with added salt compared to the control treatment. The results show that the addition of salt to the diet of Asian sea bass reared in freshwater at a level of up to 4% leads to better feed utilization coupled with a reduction in feed cost. © 2005 Elsevier B.V. All rights reserved.European CommissionThis study was funded by a grant obtained from the European Commission (contract no. ICA3-CT-2002-10001)

Effect of feeding frequency on growth, feed efficiency and nutrient utilization of juvenile flounder (Platichthys flesus luscus)

An experiment was conducted to determine the effects of optimal feeding frequency on growth performance, feed efficiency, nutrient utilization and body composition in juvenile flounder. Four feeding frequencies of one (F1), two (F2), three (F3) and four (F4) times a day were evaluated as treatments in triplicate for a period of 60 days. Forty-seven hatchery produced juveniles (2.5 ± 0.7 g) were stocked into 160-L rectangular fiberglass tanks and fed with a commercial diet containing 54 % protein to satiation. At the end of the experiment, the final weight of F1, F2, F3 and F4 were 5.06 ± 0.29, 5.91 ± 0.42, 6.24 ± 0.42 and 6.16 ± 0.46 g, respectively. Growth rates and feed consumption were highest in F3 and lowest in F1. Feed conversion ratios ranged between 0.83 ± 0.04 and 0.90 ± 0.03. There were no significant differences in either moisture or ash content of the fish groups. Protein content decreased with increasing feeding frequency, while lipid content partly increased with increasing feeding frequency. Nitrogen intake and lipid intake were significantly higher in fish fed under F3 and F4 treatment, whereas the nitrogen gain decreased and lipid gain increased with increasing feeding frequency. It is concluded that the flounder juveniles can achieve maximum growth performance and better nutrient utilization when they are fed a given ration two times a day. The findings have practical significance toward establishing an appropriate flounder nursery rearing and will directly benefit the nursery operations. © 2013 Springer Science+Business Media Dordrecht.Ministry of Agriculture, Food and Rural Affairs Bangladesh Fisheries Research InstituteAcknowledgments This study was supported by Ministry of Agriculture and Rural Affairs, the Central Fisheries Research Institute, with project entitled ‘‘Research on Rearing Possibilities of Flounder (Platichthys flesus luscus L.)’’

Effects of Dietary L-carnitine Supplementation on Growth, Muscle Fatty acid Composition and Economic Profit of Rainbow Trout (Oncorhynchus mykiss)

WOS: 000282734600003In this study, the effect of dietary L-carnitine on growth, proximate and muscle fatty acid compositions of rainbow trout (Oncorhynchus mykiss) were investigated. The fish were fed with diets containing 300 mg kg(-1) L-carnitine (LC300), other group was fed with diets containing 600 mg kg(-1) L-carnitine (LC600) and control group was not supplementary L-carnitine for 63 days. The weight gain of LC600 fed with L-carnitine supplemented was found to be 7.73% higher than in control group. Feed conversion ratio in LC600 (1.66) and LC300 (1.60) is better than in control group (2.00). L-carnitine supplemented groups would be lower cost of production than control. Economic conversion ratio (ECR) of LC300 (2.71 US.$kg) would represent a saving of 0.44 US.$ kg(-1) compared to the control. L-carnitine administration did not affect proximate composition of muscle except for protein percent. Protein content of L-carnitine supplemented groups was higher than control group. Total saturated monounsaturated and polyunsaturated muscle fatty acid content increased by L-carnitine supplementation in rainbow trout. The results indicate that supplementation of 600 mg L-carnitine/kg diet is more effective on growth than the other L-carnitine supplementation level 300 mg kg(-1) and control diet in commercial cage conditions.Scientific and Technological Research Council of Turkey (TOBITAK), TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [106O195]This work was partially supported by the Scientific and Technological Research Council of Turkey (TOBITAK), Turkey (project 106O195). We would also like to thank anonymous referees for their valuable reviews of the manuscript

Effects of different feeding levels during day and/or night on growth and brush-border enzyme activity in juvenile Lates calcarifer reared in freshwater re-circulating tanks

The Asian sea bass is a carnivorous, euryhaline species originating in seawater. It is currently being reared under intensive conditions in freshwater re-circulating ponds. The effects of feeding juvenile Asian sea bass at different levels during the day and/or night on their growth performance and on the activity of the brush border enzymes were evaluated in closed, freshwater re-circulating tanks. Contrary to previous published data, the results of the present study showed that the feeding time factor had almost no affect on fish growth rate. Asian sea bass appear to consume food whenever it is fed, even during the night. However, the feeding ration significantly affected growth rate. Restricted feeding (2% of body mass per day) significantly reduced growth rate, while feeding in excess (6% of body mass per day) did not improve it compared with a daily ration of 4%. The feeding ration also had an impact on survival, which was significantly lower in the groups which were fed 2% of body mass (during either the day or night) than in the other groups. The coefficient of variance (CV) of weights was influenced by both the feeding level and the time of feeding. It increased as the feeding ration decreased and also when the ration was fed at night. Feeding 4% during both day and night resulted in a similar growth rate to that obtained with either day or night feeding at this level. The brush border enzyme activity was affected by both the feeding time and ration. It was higher in groups fed 2% of body mass and in groups fed during the day. The proteases were affected to a greater extent than the carbohydrases. The high activity of all the tested enzymes in the pyloric caeca points towards their major importance in food digestion and absorption in this species. © 2005 Elsevier B.V. All rights reserved.European CommissionThis study was funded by a grant obtained from the European Commission, Contract no. ICA3-CT-2002-10001

Effects of dietary lipid levels on growth, nutrient utilization, and nitrogen and carbon balances in shi drum (Umbrina cirrosa L.)

Shi drum (Umbrina cirrosa L.) is regarded as a promising new candidate for Mediterranean mariculture but specifically formulated feeds are not yet available due to knowledge gaps in its basic nutritional requirements. Therefore, this study was carried out to determine the effects of dietary lipid levels on growth and feed utilization in shi drum (72. 6 g average weight). Four isonitrogenic diets differing in dietary lipid levels between 10 and 19% (named 10L, 13L, 16L, and 19L, respectively) were fed to triplicate groups of fish for 8 weeks. Growth was not affected by treatment whereas feed efficiency was significantly deteriorated in fish fed diets containing lipid higher than 13%. Whole body dry matter and lipid contents were significantly higher in fish fed 19L compared with fish fed the 10L, while whole body protein, ash, and total carbon (C) were statistically unaffected by the dietary treatment. A significant increase in feed, lipid, energy, nitrogen (N), and carbon (C) intake was recorded in fish fed 16L and 19L when compared with 10L. Carbon/nitrogen (C/N) ratio was significantly higher in fish fed 19L than 10L. Moreover, the N and C losses significantly increased in fish fed 19L compared with 10L and 13L. It was concluded that high dietary lipid did neither had any protein-sparing effect nor other positive result, and diets for shi drum are not recommended to contain more than 13% lipid. © 2011 Springer Science+Business Media B.V.Ministry of Agriculture and Rural DevelopmentAcknowledgments The General Directorate of Agricultural Research, Ministry of Agriculture and Rural Affairs, Turkey, supported this research under grant no. TAGEM/HAYSUD/2006/09/03/02. Japan International Cooperation Agency is greatly acknowledged here for their support in procurement of some feedstuffs. Ramazan Uysal and Gül Tunc¸ are very much appreciated for their contributions during the carbon analysis. We also thank Dr. Metin Kumlu and Dr. Giovanni Turchini for proofreading the English

Growth of Over-wintered and Pre-seasonally Produced Post-larvae of Penaeus semisulcatus in the Subtropics

WOS: 000282734600016Growth performance of Penaeus semisulcatus under semi-intensive and intensive systems in pond/tank culture conditions with pre-seasonally or over-wintered animals was studied in sub-tropical climate conditions of Turkey. In Pond A, the pre-seasonally produced post-larvae (PL) grew linearly from 0.2 g to 22.6 g in 140 days (Y = 0.19 X- 2.69; R-2= 0.97) with DGR (daily growth rate) of 0.06 g day(-1). In Pond B, the over-wintered juveniles grew from 3.8 g to 30.5 g with DGR of 0.41 g during the first 30 days (weight gain of 14.42 g) and 0.13 g between 30 and 140 days (weight gain of 14.32 g). Regression equation for growth was calculated to be Y = 9.62 Log (X) + 4.51 (R-2 = 0.99). Compensatory growth due to starvation or over-winter fasting has, for the first time, been demonstrated in this penaeid shrimp species in the present study. Food deprivation during the winter months resulted in growth compensation after re-feeding under appropriate culture conditions. During the compensatory growth period (first month after re-feeding), the shrimps gained an average weight of 2.87 g week(-1), but after this period, growth rate declined to 0.91 g week(-1) (over three-fold less) for the rest of the growth period (between 2(nd) and 5(th) months). This preliminary finding is a promising area on which studies should be focused on, as fasting and re-feeding strategy at low temperature can provide a chance to increase marketable size of shrimps or to even produce two crops per,year in the sub-tropics. The shrimps (0.2 g) reached to 13.7 g at 30 PL per m(2) (DGR 0.10 g), 6.44-7.37 g (DGR 0.05 g) at 40-50 PL per m(2) in 140 days. The estimated yields were 880-1,150 kg ha(-1) in semi-intensive ponds and 1,597-2,673 kg ha(-1) in intensive ponds. The shrimps grown in concrete Tanks displayed even poorer growth performance resulting in only 879 kg and 793 kg ha(-1) of yield.Research Fund of the University of CukurovaCukurova University [SUF2002 BAP24]This study was financed by the Research Fund of the University of Cukurova (SUF2002 BAP24)

A New Network for the Advancement of Marine Biotechnology in Europe and Beyond

Marine organisms produce a vast diversity of metabolites with biological activities useful for humans, e.g., cytotoxic, antioxidant, anti-microbial, insecticidal, herbicidal, anticancer, pro-osteogenic and pro-regenerative, analgesic, anti-inflammatory, anti-coagulant, cholesterol-lowering, nutritional, photoprotective, horticultural or other beneficial properties. These metabolites could help satisfy the increasing demand for alternative sources of nutraceuticals, pharmaceuticals, cosmeceuticals, food, feed, and novel bio-based products. In addition, marine biomass itself can serve as the source material for the production of various bulk commodities (e.g., biofuels, bioplastics, biomaterials). The sustainable exploitation of marine bio-resources and the development of biomolecules and polymers are also known as the growing field of marine biotechnology. Up to now, over 35,000 natural products have been characterized from marine organisms, but many more are yet to be uncovered, as the vast diversity of biota in the marine systems remains largely unexplored. Since marine biotechnology is still in its infancy, there is a need to create effective, operational, inclusive, sustainable, transnational and transdisciplinary networks with a serious and ambitious commitment for knowledge transfer, training provision, dissemination of best practices and identification of the emerging technological trends through science communication activities. A collaborative (net)work is today compelling to provide innovative solutions and products that can be commercialized to contribute to the circular bioeconomy. This perspective article highlights the importance of establishing such collaborative frameworks using the example of Ocean4Biotech, an Action within the European Cooperation in Science and Technology (COST) that connects all and any stakeholders with an interest in marine biotechnology in Europe and beyond