Effect of Soluble CO2 Stabilization on the Quality of Fillets from Farmed Gilthead Sea Bream (Sparus aurata) and European Sea Bass (Dicentrarchus labrax)     

Rogério Mendes  Amparo Gonçalves 《Journal Of Aquatic Food Product Technology》2013,22(4):342-366

ABSTRACT

Soluble gas stabilization (SGS) is a relatively recent methodology of active packaging that has been proposed to extend the shelf life of packaged fish. The aim of the present work was to study the effect of SGS applied at different extents (2 bars: 30 and 60 min) on the shelf life of sea bream and sea bass fillets packed in air during chilled storage. Quality changes were evaluated by sensory assessment, microbiological analysis (TVC), TBARs, pH value, TVB-N, and TMA-N. No significant extension of sensory shelf life was visible as a function of SGS treatment. The treatment of fillets in CO₂ at 2 bars during 60 min had a positive effect on the microbiological shelf life of both species. On the other hand, TMA-N and TVB-N showed similar changes during storage period and were not affected by the CO₂ treatment. Sea bream treated with SGS always presented higher TBARs than control samples. Nevertheless, oxidation of sea bream and in particular, of sea bass fillets, did not appear to be a significant problem during chilled storage.  相似文献   

Feasibility Study of a Fish By-Product Recovery Plant with a Processing Capacity of 1,000 kg/Day     

Maria Inez Espagnoli Geraldo Martins  Giovani Sampaio Gonçalves  Rose Meire Vidotti 《Journal Of Aquatic Food Product Technology》2013,22(8):1202-1212

ABSTRACT

This study evaluates the feasibility of producing hamburger, silage, and leather using fish by-products in a medium-sized recovery plant with total capacity of processing up to 1,000 kg/day of whole fish. The average volume of fish by-products generated daily was 673 kg. The investment necessary to introduce these three technologies was US$47,193.13 in 1 year. The average cost to produce 1 kg of hamburger, silage, and leather was 1.24, 0.17, and US$1.77, respectively. The return of the investment was 56.16%, and the net present value US$570,582.16. The investment pay back was realized in 3.88 years, with a benefit/cost relationship of 1.31. For all the studied scenarios, sale price variations most influenced the economical parameters analyzed.  相似文献   

A toxicity bioassay study concerning the effect of un-ionized ammonia on the mucus cells response originating from the gills of zebrafish Danio rerio     

Abdullah Salim Al-Zaidan  Makoto Endo  Masashi Maita  Ana Teresa Gonçalves  Kunihiko Futami  Takayuki Katagiri 《Fisheries Science》2013,79(1):129-142

Ammonia is one of the most common and pervasive pollutants in the aquatic habitat affecting the health of aquatic animals. It affects the number and morphology of mucus producing cells, resulting in excessive and irregular secretion and alterations in quantity of mucus, which can lead to complications in fish health. A toxicity test on the mucus cells localized on the gills (primary lamellae) and inner operculum epithelial lining of zebrafish Danio rerio at different periods of exposure (24, 48 and 72 h) followed by recovery periods was studied using histopathology, scanning electron microscopy and anterior gradient 2 homologue (agr2) gene expression techniques. Fish samples subjected to low, medium and high external toxic ammonia concentrations (L: 17.21 mg/l, M: 25.81 mg/l and H: 38.91 mg/l NH₃-N) were observed to display a higher mucus layer production and active secretion compared with the control. Gill cellular alterations were more severe at 48 and 72 h. A high expression of agr2 was detected at 48 h (L and M) recovery periods and a (H) exposure and recovery period indicating an increase in quantity in newly proliferated alcian blue stained mucus cells and excessive secretion observed by histopathology. Such expression decreased at 72 h resulting in a decrease in mucus cell density and secretion.  相似文献   

Dispersant use as a response to oil spills: toxicological effects on fish cardiac performance     

Thomas Milinkovitch  Hélène Thomas-Guyon  Christel Lefrançois  Nathalie Imbert 《Fish physiology and biochemistry》2013,39(2):257-262

Dispersant use is a controversial technique used to respond to oil spills in nearshore areas. In order to assess the toxicity of this technique, this study evaluated the cardiac toxicological effects on juvenile golden grey mullets Liza aurata exposed for 48 h to either dispersant alone, chemically dispersed oil, mechanically dispersed oil, the water-soluble fraction of oil or a control condition. Following exposure, the positive inotropic effects of adrenaline were assessed in order to evaluate a potential impairment on the cardiac performance. The results revealed an impairment of the positive inotropic effects of adrenaline for all the contaminants (single dispersant, dispersed and undispersed oil, water-soluble fraction of oil). This suggests that: (1) cardiac performance is a valuable parameter to study the physiopathological effects of dispersed oil; (2) dispersant application is likely to impair cardiac performance.  相似文献   

Self-thinning dynamics in experimental scallop populations     

Marcel Fréchette  José Manuel Urquiza  Gaétan Daigle  Dominique Maheux  Jean-François Dumais 《Aquaculture International》2013,21(3):539-551

Self-thinning-related mortality has been encountered in extensively cultured scallop populations. Here we report an experiment aimed at studying actual population dynamics of scallops undergoing self-thinning and develop a model of the process. Scallops were kept in small tanks at various initial population densities. Growth and survival were monitored for 39 months. Two cohorts were monitored (cohorts 1 and 2 were 1 and 2 years old, respectively). Growth was density-dependent in cohort 2. Survivorship was high in cohort 1 during the first summer but mass mortality occurred during the second summer. Mortality in cohort 2 peaked during the first summer. In both cohorts, peak mortality occurred at age 2+ years and thus was uncoupled among cohorts. Therefore, negative environmental factors are ruled out as explanations of mortality. Instead, it appears as if self-thinning interacted with some ontogenetic factor. Although cohort 1 was undergoing self-thinning, trends in biomass–density curves were non-monotonous because of mass mortality. In contrast, self-thinning in cohort 2 followed a classical pattern. One possible mechanism for such contrasting differences was that 1+-year-old scallops produced byssal threads and attached to one another during the first year, forming multilayered clumps. This behaviour disappeared during the second year and mass mortality was experienced as scallops adopted a single-layered arrangement. Although details may differ among species, the process depicted above provides a potential trigger to the sequence of events leading to mass mortality in scallop culture. Our model suggests that self-thinning occurred in all density groups, with a common slope but with different elevations in the biomass–density space.  相似文献   

Ontogenetic variation of food intake and gut evacuation rate in larvae of the doncella Pseudoplatystoma punctifer,as measured using a non‐destructive method     

Etienne Baras  Grace V. Montalvan Naranjos  Dustin V. Silva del Aguila  Fred Chu Koo  Rémi Dugué  Carlos Chavez  Fabrice Duponchelle  Jean‐François Renno  C. Carmen Garcia‐Dávila  Jesus Nuñez 《Aquaculture Research》2012,43(12):1764-1776

Food intake (FI) and gut evacuation (Rg) were measured in larvae of Pseudoplatystoma punctifer (4.5–18.4 mm SL) fed Artemia nauplii, taking advantage of the translucence of their abdominal region to achieve this in a non‐destructive way, using digital photographs and mathematical reconstruction of gut volume content (ellipsoidal and cylindrical models for stomach and intestine respectively). The inaccuracy of the method, with reference to counts of nauplii following fish dissection, was low (2.9 ± 1.5%) and independent of fish size (P = 0.6153). Pigmentation hampered measurement in fish >18–19 mm SL. Anaesthesia was needed in fish >9.5 mm SL, thereby preventing the measurement of Rg in individual fish. The FI increased rapidly during the ontogeny, passing from <7% M at 0.6 mg, to 14% M at 1 mg and 21% M at 15–40 mg, and then decreased slightly in larger fish. At 28.5°C, Rg (% M h^?1) was modelled as Rg = ?8.22 + 12.11 log FI + 6.30 log M – 12.67 (log M)² (R² = 0.904, d.f. = 27, with FI in% M and M in mg). Extrapolations of Rg over 24 h gave estimates of daily food rations that fit well with those measured in cannibalistic P. punctifer.  相似文献   

Structural features of lignin obtained at different alkaline oxidation conditions from sugarcane bagasse   总被引：1，自引：0，他引：1  

Priscila Maziero  Mario de Oliveira Neto  Douglas MachadoTatiana Batista  Carla Cristina Schmitt CavalheiroMiguel G. Neumann  Aldo Felix CraievichGeorge Jackson de Moraes Rocha  Igor Polikarpov  Adilson Roberto Gonçalves 《Industrial Crops and Products》2012,35(1):61-69

Lignin is a macromolecule frequently obtained as residue during technological processing of biomass. Modifications in chemical structure of lignin generate valuable products, some with particular and unique characteristics. One of the available methods for modification of industrial lignin is oxidation by hydrogen peroxide. In this work, we conducted systematic studies of the oxidation process that were carried out at various pHs and oxidizing agent concentrations. Biophysical, biochemical, structural properties of the oxidized lignin were analyzed by UV spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy and small angle X-ray scattering. Our results reveal that lignin oxidized with 9.1% H₂O₂ (m/v) at pH 13.3 has the highest fragmentation, oxidation degree and stability. Although this processing condition might be considered quite severe, we have concluded that the stability of the obtained oxidized lignin was greatly increased. Therefore, the identified processing conditions of oxidation may be of practical interest for industrial applications.  相似文献   

Synthesis and characterization of acrylic fibers-<Emphasis Type="Italic">g</Emphasis>-polyacrylamide     

Meltem Çelik  Mohammad L. Qudrat  Emel Akyüz  Leyla Açik 《Fibers and Polymers》2012,13(2):145-152

Graft copolymerization of acrylamide onto commercial acrylic fibers was carried out using benzoyl peroxide as a free-radical initiator in aqueous medium within the 75–95 °C temperature range. In this study, the effects of initiator and monomer concentration, the amount of fiber, polymerization time, and temperature on the graft yield were investigated. The optimum concentration for initiator was found to be 2.0×10⁻³ mol/l and the optimum temperature of 85 °C. The activation energy of the reaction was calculated to as 35.81 kJ/mol at the temperature interval of 75–95 °C. The structures and morphologies characterization of grafted fibers was investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The thermogravimetric analysis data showed that the thermal stability of the acrylic fibers increased with graft yield. The scanning electron photographs showed that the homogeneous appearance of the fiber surface changed and a shell-like heterogeneous structure occurred at the surface with an increasing degree of grafting. The moisture content, water absorption, dyeability, and antimicrobial activity of grafted acrylic fibers were also reported. The results showed that grafting of polyAAm improved the moisture contain, water absorption, dyeability, and antimicrobial activity of fiber.  相似文献   

Effects of brood size manipulation and common origin on phenotype and telomere length in nestling collared flycatchers     

M Voillemot  K Hine  S Zahn  F Criscuolo  L Gustafsson  B Doligez  P Bize 《BMC ecology》2012,12(1):17

ABSTRACT: BACKGROUND: Evidence is accumulating that telomere length is a good predictor of life expectancy, especially early in life, thus calling for determining the factors that affect telomere length at this stage. Here, we investigated the relative influence of early growth conditions and origin (genetics and early maternal effects) on telomere length of collared flycatchers (Ficedula albicollis) at fledging. We experimentally transferred hatchlings among brood triplets to create reduced, control (i.e. unchanged final nestling number) and enlarged broods. RESULTS: Although our treatment significantly affected body mass at fledging, we found no evidence that increased sibling competition affected nestling tarsus length and telomere length. However, mixed models showed that brood triplets explained a significant part of the variance in body mass (18%) and telomere length (19%), but not tarsus length (13%), emphasizing that unmanipulated early environmental factors influenced telomere length. These models also revealed low, but significant, heritability of telomere length (h2 = 0.09). For comparison, the heritability of nestling body mass and tarsus length was 0.36 and 0.39, respectively, which was in the range of previously published estimates for those two traits in this species. CONCLUSION: Those findings in a wild bird population demonstrate that telomere length at the end of the growth period is weakly, but significantly, determined by genetic and/or maternal factors taking place before hatching. However, we found no evidence that the brood size manipulation experiment, and by extension the early growth conditions, influenced nestling telomere length. The weak heritability of telomere length suggests a close association with fitness in natural populations.  相似文献   

Purification and partial characterization of vitellogenin from spotted wolffish (Anarhichas minor) and development of an enzyme-linked immunosorbent assay for the determination of gender and sexual maturity     

Domynick Maltais  Bernard-Antonin Dupont-Cyr  Robert L. Roy  Nathalie R. Le François 《Fish physiology and biochemistry》2014,40(1):279-294

Vitellogenin (VTG) from spotted wolffish, Anarhichas minor, a candidate species for cold-water marine aquaculture, was purified by MgCl₂/EDTA precipitation followed by a two-step chromatographic procedure. VTG had an apparent molecular mass of 470 kDa, as determined by gel filtration, and an amino acid composition similar to those of other teleosts. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of the purified VTG revealed a major band with a relative molecular weight of 166 kDa and some minor bands. Spotted wolffish VTG (sw-VTG) is relatively robust to in vitro degradation, as shown when samples of purified VTG and plasma from mature females subjected to various storage conditions or multiple freeze/thaw cycles were analyzed by Western blot. We developed an indirect competitive enzyme-linked immunosorbent assay (ELISA) using an antibody against Atlantic wolffish (Anarhichas lupus) VTG and purified sw-VTG. The ELISA had a detection limit of 6.7 ng/ml and a working range of 16.2–787.5 ng/ml, with intra- and inter-assay coefficients of variation ranging from 1.5 to 7.3 % and 7.1 to 14.3 %, respectively. The assay could distinguish males from immature females and discriminate maturing females at different stage of oocyte development. These results suggest that the sw-VTG ELISA would be useful in spotted wolffish aquaculture to determine sex and monitor female maturation.  相似文献