Effects of stocking density on reared Siberian sturgeon (Acipenser baerii) larval growth, muscle development and fatty acids composition in a recirculating aquaculture system

This study evaluated the effects of rearing density on muscle growth and development in Siberian sturgeon (Acipenser baerii) larvae. Three different stocking densities were tested: low (LD, 30 larvae/l), mid (MD, 80 larvae/l) and high (HD, 150 larvae/l) in a recirculating aquaculture system. Larvae were sampled at hatching (T0), schooling (T1) and complete yolk-sac absorption (T2) stage and were weighed and processed for muscle tissue histometrical analyses and for qualitative morphological study analyses; fatty acid profile was also determined by Gas Chromatography\u2014Flame Ionization Detector analysis. Low-density larvae presented a higher weight than MD or HD at T2 (p < 0.05). Histometrical analysis revealed that total muscle area was similar at T1 and T2, but higher than T0, while it was lower at HD at schooling (p < 0.05). The fatty acid profile revealed no differences between densities while, during development, there was a selective consumption: sparing or increasing of essential fatty acids to the detriment of their precursors. Our study suggests that lower densities appear to be more suitable to rear Siberian sturgeon in this particular stage of development. Indeed, larvae reared at the lower density were heavier and longer while larvae reared at the higher density showed lower muscle proliferation rate. As a consequence, LD larvae may exert an increase of potential growth at a mid-long term

Effects of different rearing temperatures on muscle development and stress response in the early larval stages of acipenser baerii

The present study aims at investigating muscle development and stress response in early stages of Siberian sturgeon when subjected to different rearing temperatures, by analysing growth and development of the muscle and by assessing the stress response of yolk-sac larvae. Siberian sturgeon larvae were reared at 16\uc2\ub0C, 19\uc2\ub0C and 22\uc2\ub0C until the yolk-sac was completely absorbed. Sampling timepoints were: hatching, schooling and complete yolk-sac absorption stage. Histometrical, histochemical and immunohistochemical analyses were performed in order to characterize muscle growth (total muscle area, TMA; slow muscle area, SMA; fast muscle area, FMA), development (anti-prolif erating cell nuclear antigen -PCNA or anticaspase) as well as stress conditions by specific stress biomarkers (heat shock protein 70 or 90, HSP70 or HSP90). Larvae subjected to the highest water temperature showed a faster yolk-sac absorption. Histometry revealed that both TMA and FMA were larger in the schooling stage at 19\uc2\ub0C while no differences were observed in the SMA at any of the tested rearing temperatures. PCNA quantification revealed a significantly higher number of proliferating cells in the yolk-sac absorption phase at 22\uc2\ub0C than at 16\uc2\ub0C. HSP90 immunopositivity seems to be particularly evident at 19\uc2\ub0C. HPS70 immunopositivity was never observed in the developing lateral muscle

Influence of vegetable diets on physiological and immune responses to thermal stress in Senegalese sole (Solea senegalensis)

The substitution of fish resources as ingredients for aquafeeds by those based on vegetable sources is needed to ensure aquaculture sustainability in the future. It is known that Senegalese sole (Solea senegalensis) accepts high dietary content of plant ingredients without altering growth or flesh quality parameters. However, scarce information is available regarding the long-term impact of vegetable diets (combining the inclusion of both vegetable protein and oils) on the stress response and immunity of this fish species. This study aims to evaluate the concomitant effect of the extended use of vegetable protein-based diets with fish oil (FO) replacement (0, 50 or 100%) by vegetable oils (VO), on the response to acute (10 min) or prolonged (4 days) stress, induced by thermal shock. Plasma levels of cortisol, glucose and lactate as well as hepatic levels of glucose, glycogen and lactate were evaluated as primary and secondary responses to stress, 6 and 18 months after feeding the experimental diets (6 and 18 MAF). The brain monoaminergic activity in telencephalon and hypothalamus, and non-specific immune parameters were also evaluated. As expected, thermal shock induced an increase in values of plasma parameters related to stress, which was more evident in acute than in prolonged stress. Stress also affected lactate levels in the liver and the values of the alternative complement pathway-ACH50 in the plasma. Dietary substitution of FO induced an effect per se on some parameters such as decreased hepatic glucose and glycogen levels and peroxidase activity in plasma as well enhanced serotonergic activity in brain of non-stressed fish. The results obtained in some parameters indicate that there is an interaction between the use of vegetable diets with the physiological response to thermal stress, as is the case of the hepatic lactate, serotonergic neurotransmission in brain, and the activity of ACH50 in plasma. These results suggest that the inclusion of VO in plant protein based diets point to a slightly inhibited stress response, more evident for an acute than a prolonged stress. © 2018 Conde-Sieira et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This research was partially supported by the Strategic Funding UID/Multi/04423/2013 through national funds provided by FCT–Foundation for Science and Technology and European Regional Development Fund (ERDF), in the framework of the programme PT2020" to L.M.P.V, and by research a grant from Spanish Agencia Estatal de Investigacio´n and European Fund for Regional Development (AGL 2016-74857-C3-1-R and FEDER) to J.L.S. M.C-S. is supported by a postdoctoral grant from Xunta de Galicia (Plan I2C). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. There are no conflicts of interest in connection with the present study

Total substitution of dietary fish oil by vegetable oils stimulates muscle hypertrophic growth in Senegalese sole and the upregulation of fgf6

The long term effects of fish oil (FO) substitution by increasing the levels of vegetable oils (VO), 0% (CTR), 50% (VO50) and 100% (VO100), in diets for Senegalese sole were evaluated in terms of skeletal muscle cellularity and expression of related genes. After 140 days of feeding, all fish had similar body weight and length. The inclusion of 50% VO did not result in differences in muscle cellularity, but dorsal muscle cross-sectional area and fast-twitch fibre diameter increased in fish fed total FO substitution, whilst fibre density was reduced (P < 0.05) in relation to CTR. The total number of fibres was similar in all treatments. FO substitution did not affect the transcript levels of myogenic genes (myf5, mrf4, myog, myod1, myod2), but resulted in a two-fold increase of fgf6 transcript levels compared to CTR (P < 0.05). The relative expression of igf-I was higher in VO100 than in VO50, but was similar to CTR. FO substitution resulted in cellularity changes related to the stimulation of muscle hypertrophic growth, but not hyperplastic growth, and associated with a nutritional modulation of fgf6 by dietary VO. This study indicates that 50% VO does not affect the muscle phenotype, but total FO substitution stimulates muscle hypertrophy. © 2017 The Royal Society of Chemistry.This work was partially supported by NORTE-07-0124-FEDER-000038, in the context of the North Region Operational Programme (ON.2-O Novo Norte), under the project Sustainable Aquaculture and Animal Welfare (AQUAIMPROV) and the FCT research strategic funding UID/Multi/04423/2013

Partial replacement of fish oil by flaxseed oil in Atlantic halibut (Hippoglossus hippoglossus L.) diets: Effects on growth, nutritional and sensory quality

Three isonitrogenous (520gproteinkg -1DM) and isoenergetic (25MJkg -1DM) diets containing increasing levels of flaxseed oil (FxO; 0%, 40% and 70% of total added oil) at the expense of fish oil (FO) were tested for 33weeks in groups of 61 individually PIT-tagged halibut (initial weight, 849\ub199g). Effects on fish growth performance, fillet nutritional and sensory quality were determined. Specific growth rate (0.2%day -1), feed conversion ratio (1.2-1.3) and nitrogen and energy retention were not affected by dietary treatments. Dietary fatty acid composition was reflected in fatty acid profiles of halibut muscle, liver and heart. Muscle of fish fed FxO diets contained higher 18:2n-6 and 18:3n-3 concentrations whereas 20:5n-3 and 22:6n-3 levels were significantly reduced. However, increasing FO replacement induced preferential retention of 22:6n-3 especially in heart, and a trend for 20:5n-3 conservation in heart and muscle was observed. FO replacement did not affect colour, texture and the characteristic fish odour and flavour of cooked fillets. By selectively retaining long-chain polyunsaturated fatty acids halibut can adapt to a lower dietary supply without adverse effects on growth, feed conversion ratio, survival, and fillet nutritional and sensory quality. \ua9 2011 Blackwell Publishing Ltd.Peer reviewed: YesNRC publication: Ye

Feed intake and growth of fast and slow growing strains of rainbow trout (Oncorhynchus mykiss) fed by automatic feeders or by self-feeders

International audienc

Impact of different thermal treatments and storage conditions on the stability of soybean byproduct (okara)

Okara is the byproduct obtained from tofu or soymilk production process. It has a rich nutritional composition, especially in fibers, proteins and lipids. Stabilization processes are required to assure its efficient and safe use, because there are few studies on okara. The main objective of this study was to evaluate the chemical composition (protein, fiber, lipids, ash and isoflavones), microbiological stability, antioxidant capacity and antinutritional factors in fresh okara stored at 4 and − 18 °C and dried okara (80 °C/5 h and 200 °C/1 h) stored at room temperature for 15 days. Okara showed a rich nutritional composition— ca. 35% of fiber, 30% of protein and 11% of lipids. The okara’s lipid profile showed high and valuable level of PUFA (ca. 56%) followed by MUFA (ca. 21%) and SFA (ca. 23%). The Fresh okara showed the highest antioxidant activity and total phenols, however for isoflavones (genistin, genistein, daidzin, daidzein) the dried okara at 200 °C exhibited higher content compared to dried okara at 80 °C and fresh okara. Okara samples submitted to thermal treatment showed a decrease in antinutritional factors in relation with fresh okara, whereas the treatment of dried okara at 200 °C was the most efficient inducing a decrease of ca. 6 times. In conclusion, the nutritional richness of this byproduct suggests okara as a valuable nutritional ingredient for further inclusion in food and feed, but considering the limited studies carried out to date, further studies are warranted to better stabilize okara.info:eu-repo/semantics/publishedVersio

Place-Based Policies for Sustainability and Rural Development: the Case of a Portuguese Village “Spun” in Traditional Linen

In recent decades, European rural development policies have transitioned toward a more place-based approach. This claim rests on the assumption that the diversity of resources within rural areas can be a potential source for place-shaping practices and sustainability. Moreover, this shift away from a top-down sectorial toward a more territorial focus has also shed light on the importance of agency, relations, and how people engage. Many rural areas in Europe, and particularly in Portugal, have seen a withdrawal of focus away from agriculture toward more diversified activities, where place-based approaches can untap local potential, stimulate sustainable place-shaping practices, and create significant well-being. However, some rural communities have difficulties in capitalizing on them due to unfavorable demographics such as depopulation and aging, a focus on traditional industries, and a lack of technical knowledge. The aim of the article is to discuss the role of place-based policies for enabling place-shaping practices revolving around traditional resources in rural areas and their contribution to sustainability. The study briefly highlights the recent debate around European rural development policies and illustrates their implementation through place-shaping practices via a case study in a Portuguese rural village—Várzea de Calde. The village revalorized itself and is trying to tackle marginalization processes through its traditional linen, which is a local material and immaterial resource, via collective agency and a strong sense of identity. The case study will provide empirical insights in discussing the effects of sustainable place-shaping practices stimulating by place-based policy instruments. Our conclusions highlight the positive contributions toward sustainability through improvements in social (e.g., identity) and economic well-being

Dietary protein/carbohydrate ratio in low-lipid diets for Senegalese sole (Solea senegalensis, Kaup 1858) juveniles. Influence on growth performance, nutrient utilization and flesh quality

Four isoenergetic (21 kJ/g dry matter, DM) and isolipidic (65 g/kg DM) diets containing different crude protein/total carbohydrate (CHO) ratios: 60/26, 56/30, 52/34 and 48/38, were tested in 22 g Senegalese sole for 104 days. Apparent digestibility coefficients (ADC) were not affected by the treatments, and all groups presented extremely low starch ADC values (22.8%\u201336.5%). Replacement of dietary protein by CHO did not affect daily growth index (0.9\u20131.0), but significantly increased voluntary feed intake of fish. Regression analyses demonstrated that digestible protein content, rather than digestible energy, was the main dietary factor influencing such feeding activity (R2 = .952). A significantly increased feed conversion ratio was observed in sole fed increasing CHO contents. The dietary protein/CHO ratio did not influence whole-body composition. Sole fed the 48/38 diet showed the lowest efficiency in terms of N and energy utilization. PUFA were the most represented fatty acid fraction in fillet, regardless of the dietary protein/CHO ratio, mainly due to the high content of DHA. Senegalese sole increase feed intake under low dietary protein/CHO ratios to ensure an adequate N intake. Such compensatory mechanism seems to be triggered to satisfy a specific protein metabolic requirement for energy purposes as tissue accretion remained unchanged

Physiopathological responses of sole (Solea senegalensis) subjected to bacterial infection and handling stress after probiotic treatment with autochthonous bacteria

This study aimed to evaluate the protective effects of four autochthonous bacteria isolated from juvenile sole (Solea senegalensis) intestine as dietary probiotic supplement against bacterial pathogen infection and handling/transport stressors. Growth performance and immune responses were evaluated after 85 days of feeding trial. Sole (IBW=16.07 ± 0.11 g) were fed six experimental diets, a control diet (CTRL, without the dietary probiotic supplementation), and five diets supplemented with probiotic bacteria: PB1 (Shewanella hafniensis), PB2 (Enterococcus raffinosus), PB3 (Shewanella hafniensis + Arthrobacter soli), PB4 (Pseudomonas protegens + Arthrobacter soli) and PB5 (Shewanella hafniensis + Arthrobacter soli + Enterococcus raffinosus). All bacteria were selected based on their in vitro antimicrobial activity. After the growth trial, fish were submitted to a stress factor (transport) and then each dietary group was divided in two additional groups: non-infected (placebo) and infected with Photobacterium damselae subsp. piscicida. Immune and antioxidant responses were evaluated at day 10 post-infection. In infection trial A, fish were infected on the same day of transport, whereas in trial B fish were infected after a 7-day recovery from the transport stress. At the end of the feeding trial, fish fed with PB2 and PB4 showed lower final body weight when compared with the other dietary groups. Respiratory burst activity and nitric oxide production were not affected by probiotic supplementation. Fish fed with PB5 presented lower peroxidase activity compared to CTRL. Lysozyme and alternative complement pathway activity (ACH50) showed no significant differences between treatments. The innate immune responses were significantly affected after handling stress and bacterial infection. In trial A, the ACH50 levels of infected fish were significantly lower than the placebo groups. On the other hand, in trial B fish infected with Pdp demonstrated higher ACH50 levels when compared to placebos. Peroxidase levels were strongly modulated by bacterial infection and handling stress. In trials A and B, infection had a clear downgrade effect in peroxidase levels. Lipid peroxidation, catalase, glutathione S-transferase and glutathione reductase were altered by both bacterial infection and transport. Overall, dietary probiotic supplementation did not influence growth performance of sole. The immune and oxidative defenses of sole responded differently to infection depending on the probiotic and the synergy between pathogen infection and transport.info:eu-repo/semantics/publishedVersio