Effect of temperature and phytoplankton concentration of Partitioned Aquaculture System water on freshwater mussel filtration

The freshwater mussel Elliptio complanata was provided green algal‐dominated water from a Partitioned Aquaculture System (PAS) over a range of water temperatures (6.1–32.4 °C) and suspended particulate organic carbon (POC) concentrations (<1–32.2 mg C L^?1) to determine filtration rates as mg POC kg^?1 wet tissue weight h^?1. The lowest filtration rates were observed at lowest temperatures and POC concentrations while the highest rates were at intermediate temperatures and the highest POC levels. The predicted filtration rate (PFR) in response to water temperature and POC concentrations was as follows: ln PFR=1.4352+0.1192 POC+0.1399 T?0.0001 T³. Within the experimental conditions, PFRs at any POC concentration increased with increased water temperature to a peak at 22 °C and then decreased. The maximum PFR occurred at 22 °C and 32 mg C L^?1 and the minimum PFR at 7 °C and 1 mg C L^?1. A model to describe the mussel filtration rate responses to PAS water conditions involves both water temperature and POC concentration.     

Protein Dispersions and Hydrolysates from Shark (Isurus oxyrinchus)

Manually-deboned muscles of shark (Isurus oxyrinchus) were ground and then washed sequentially with water, 0.5% NaCl and 0.5% NaHC0₃ solutions. Washed myofibrillar proteins were dispersed in water and then acidified. Dispersions so obtained were stable to heat treatment at 100°C followed by centrifugation at 5000 x g, as approximately 90% of proteins remained in solution. The acidified dispersions had low solubility in the pH range of 5 to 8, but were highly soluble under other pH conditions. Apparent viscosity of dispersions was dependent on temperature, pH and protein concentration. The amino acid composition and calculated protein efficiency ratio (PER) of washed proteins were similar to that of the original meat; howevcr, over 85% of free amino acids were removed upon aqueous washings of the meat. Hydrolysates obtained via an Alcalase-assisted process from the original shark muscles or washed myofibrillar proteins exhibited unique functional characteristics with respect to their water-holding capacity and emulsifying properties.     

Effect of extenders on sperm cryopreservation of African catfish, Clarias gariepinus (Burchell)

The effect of extenders was studied on the cryopreservation of sperm from African catfish, Clarias gariepinus (Burchell). The following six basic extenders were tested: fructose, glucose, sucrose, NaCl, KCl solutions and the artificial seminal plasma of the African catfish. Each of these extenders was tested both with and without buffer systems (i.e. NaHCO₃-CO₂ and Tris-HCl) by using 10% dimethyl-sulphoxide (DMSO) as a cryoprotectant. The two-step freezing was carried out in a programmable freezer by using the following freezing rates: (1) 4 °C min^–1 between 3 and –4 °C; (2) and 11 °C min^–1 between –4 and –80 °C. The best post-thaw motility (25%) was achieved with 333 mmol L^–1 fructose solution and NaHCO₃ buffer. The fertilization experiments were carried out with unbuffered fructose and glucose extenders using various amounts of sperm and two fertilization methods: (1) dry and (2) wet. The best fertilization rates were achieved with 75 μL of sperm and wet fertilization with glucose extender, or 100 μL of sperm and dry fertilization in case of fructose – both methods fertilized 96% of all eggs.     

Determination of Salt Diffusion Coefficient in Rainbow Trout (Oncorhynchus mykiss)

ABSTRACT

The diffusion properties of sodium chloride in rainbow trout muscle during dry salting at 10°C were investigated. The average initial dry matter content of the samples increased from 27.80 ± 0.10 to 36.01 ± 0.16%, and the average salt content increased to 17.98 ± 0.38 g NaCl/100 g dry matter at the end of the 10-h dry salting process. The analytical solution of Fick’s second law considering one-dimensional diffusion through an infinite slab was used to calculate effective salt diffusion coefficients (D_eff). The D_eff values in rainbow trout fillets decreased with increasing salting time and ranged from 6.64 × 10^?10 to 16.45 × 10^?10 m²/s.     

Nutritive value of partially dehulled and extruded sunflower meal for post-smolt Atlantic salmon (Salmo salar L.) in sea water

This study determined the digestibility of protein in partially dehulled sunflower meal (SFM) and then, as the main goal, the nutritive value of high‐temperature extruded (≤149°C) partially dehulled SFM (SFM_EX) for post‐smolt Atlantic salmon Salmo salar in sea water. The digestibility study was conducted using the settling column approach (‘Guelph system’) for faeces collection as described by Hajen, Higgs, Beames and Dosanjh. In the nutritive value study, triplicate groups of 50 salmon (mean weight ～116 g) in 4000‐L outdoor fibreglass tanks supplied with 25–40 L min^?1, filtered, oxygenated (dissolved oxygen, 7.0–8.5 mg L^?1), 11–12°C sea water (salinity, 29–31 g L^?1), were fed twice daily to satiation one of five steam‐pelleted dry diets that contained 422 g of digestible protein (DP) kg^?1 and ～16.4 MJ of digestible energy (DE) kg^?1 on a dry weight basis for 84 days. Low‐temperature‐dried anchovy meal (LT‐AM) comprised 68.2% of the basal diet protein whereas in four test diets, SFM_EX progressively replaced up to 33.0% of the DP provided by LT‐AM in the basal diet (SFM_EX≤271 g kg^?1 of dry matter). Sunflower meal had 87.9% DP. Diet treatment did not significantly affect specific growth rate (1.39–1.45% day^?1), feed efficiency (1.19–1.26), percentage of dietary protein retained (45.8–47.5), gross energy utilization (46.5–49.4%), per cent survival (96.0–99.3) or terminal whole body and muscle proximate compositions. We conclude that SFM_EX can comprise ≥271 g kg^?1 of the dry diet or ≥22.7% of the digestible dietary protein of post‐smolt Atlantic salmon in seawater without any adverse effects on their performance.     

Quality Characteristics of Tilapia Surimi: Effect of Single Washing Cycle and Different Washing Media

Surimi was prepared by washing with single washing cycle with cold water (T-1), alkaline saline (0.2% NaHCO₃ and 0.15% NaCl; T-2) solution, and with calcium chloride and salt (0.2% CaCl₂ and 0.1% NaCl; T-3), respectively, and compared with conventional washed (CW) surimi. T-2 exhibited significantly (p ≤ 0.05) increased moisture content, which correlated with increased yield, pH and also significantly decreased lipid and ash content. A significant (p ≤ 0.05) decrease in expressible moisture content was also observed in T-2, which suggested higher water holding capacity compared to other treatments. Heat-induced surimi gels exhibited highest L* (p ≤ 0.05), followed by surimi in all the treatments. In the case of L*, T-1 showed highest lightness, followed by T-2, which was comparable to CW. The lowest myoglobin content was exhibited by CW surimi (p ≤ 0.05), which is due to repeated washings. T-2 gel showed higher elasticity, texture, and overall acceptability than others (p ≤ 0.05), except for the whiteness. In all the aspects, T-2 was comparable with CW. Washing with one cycle of T-2 solution can not only improve the quality of surimi but can reduce the wastage of water that is released into the environment without further treatment.     

Digestive enzymes and in-vitro digestibility of different species of phytoplankton for culture of the freshwater pearl mussel, <Emphasis Type="Italic">Hyriopsis</Emphasis> (<Emphasis Type="Italic">Hyriopsis</Emphasis>) <Emphasis Type="Italic">bialatus</Emphasis>

Hyriopsis (Hyriopsis) bialatus has been cultured during the mussel life cycle from glochidia to the adult stage with a low total survival of 6% up to 130-day-old juveniles. The main digestive enzymes (amylase and proteinases) were not detectable in one-day-old juveniles, and increased during development. The stomach, including digestive glands, was the major digestive organ for both carbohydrate and protein. The optimum conditions for amylase activity were 40°C and pH 7; for acidic proteinases they were 60°C and pH 5. Two main alkaline proteinases were found in the intestine, with optimum conditions of 30°C and pH 8 and 60°C and pH 8. To improve mussel survival by finding suitable phytoplankton species and age as food for juveniles and adults, an in-vitro digestibility test was performed on ten algal species three and seven days old using amylase and proteinases in crude enzyme extracts from different mussel life stages. Among the phytoplankton selected, the three most efficiently digested by juveniles were seven-day-old Chlorella sp.2, seven-day-old Chlorococcum sp. and seven-day-old Kirchneriella incurvata, in the ratio 1:1:3 for 30-day-old juveniles and 3:1:1 for 130-day-old juveniles. For the adult mussel, three-day-old Chlorella sp.2, seven-day-old Coccomyxa sp., and seven-day-old Monoraphidium sp., in the ratio 3:1:1, were the most digestible phytoplankton. Levels of in-vitro digestibility were related to the quality (not the concentrations) of carbohydrate and protein in the phytoplankton mixtures, and protein digestibility seemed to be the key factor determining food quality for the mussel.     

Characteristics and Select Functional Properties of Collagen from Golden Pompano (Trachinotus ovatus) Skins

Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) from golden pompano skins were extracted and characterized. The molecular weight of ASC was about 130 kDa for α₁ and 115 kDa for α₂, which were slightly higher than those of PSC. Similar amino acid composition and Fourier transform infrared (FTIR) spectra were observed in both collagens, but slight differences were found in the peptide maps of collagen digested by V8 protease and trypsin. The denaturation temperatures (Tds) of ASC and PSC calculated from the reduced viscosity were 31.8 and 30.0°C, while the transition temperature (T_m) of ASC and PSC analyzed by DSC were 33.0 and 32.0°C, respectively. ASC has a lag phase, a growth phase, and a plateau phase in the turbidity–time curve, while PSC does not have similar phenomenon. It was found that the fibril gel of ASC could be formed at 25°C, leading to improved thermal stability.     

Effects of temperature on growth, survival and body composition in larvae of barbel, Barbus barbus (L.)

Barbel larvae were reared for 21 days at 21.0, 24.1, 27.2 or 30.0 °C and fed ad libitum live Artemia nauplii for 16 h a day. The final survival rates exceeded 99 %. The highest mean daily growth rates, amounting to 0.97 mm total length (TL) and 17.3 % body weight (BW), were found at 27.2 °C. The optimum temperature calculated for the growth of larvae was 26.9 °C for TL and 26.5 °C for BW. An increase in water temperature accelerated the development rate to a larger degree than the growth rate. Temperature significantly influenced the final fish body chemical composition. The lowest dry matter content (19.1 %) was found at 24.1 °C. The highest values of ash content were determined for 27.2 and 30.0 °C and were 11.3 and 11.0 % of dry matter, respectively. The fish body caloric value was the highest at 30.0 °C (30.0 J mg^?1). The analysis of changes in the fish body chemical features against the effective day-degrees age scale did not reveal significant influence of temperature. Therefore, the effects of temperature on larval body composition seem to be related mainly to differences in barbel developmental progress at particular temperatures.     

Effect of fish size and temperature on the utilization of different protein sources in two catfish species

Two sets of feeding trial were conducted to determine the effect of size and temperature on the utilization of different protein sources in two catfish species. In both the experiments, the fish were fed to apparent satiation daily at 08.00 and 18.00 hours, and faecal matter collected through slow siphoning. The first experiment was designed to study the effect of fish size on apparent digestibility coefficients for plant and animal proteins in the African catfish, Clarias gariepinus (Burchell, 1822). Three size classes (105–109 g; 780–830 g; 1250– 1300 g) of fish were stocked in triplicate sets of 600‐L plastic pools fitted with a flow‐through system (2 L min^?1). Within each size class, the apparent digestibility coefficient (ADC) for protein varied significantly with the source and quality of protein used. Soybean meal and fishmeal protein were utilized with greater efficiency, whereas rice bran protein was least digestible. An increase in ADC protein was apparent with increase in fish size for high protein sources such as soybean meal, full‐fat soybean, laboratory‐prepared fishmeal, steam‐cooked brown fishmeal and dried fish. ADC protein for other ingredients decreased with increase in size. In the second experiment, the influence of varying temperature on ADC for protein was determined in the catfish, Heteropneustes fossilis (Bloch) (6–8 g). Triplicate groups of 25 fish were kept at three different ambient temperatures (18, 28 and 38 °C), in 70‐L polyvinyl indoor flow‐through (1–1.5 L min^?1) circular tanks (water volume = 55 L). The trend in utilization of protein from different sources remained similar at the three temperatures. For each ingredient, digestibility values obtained at 18 °C were significantly lower than those obtained at 28 °C and 38 °C. Optimal protein utilization in H. fossilis was measured at 28 °C.     

Diet and water temperature affect growth and body deformities in juvenile tench Tinca tinca (L.) reared under controlled conditions

The experiment was designed to determine the combined effect of fish diet and water temperature on juvenile tench Tinca tinca (L.). Three diets were used: commercial dry diet for fish Aller Futura (diet F); frozen Chironomidae larvae (diet C); and Aller Futura substituted with Chironomidae at a ratio of 3:2 (dry weight; diet FC). Daily food rations and duration of the experiment were adjusted to temperatures of 20°C, 23°C and 26°C based on a correction factor q equal to 1.000, 0.779 and 0.609 respectively. The experiment lasted 92, 72 and 56 days for the respective temperatures. No mortality occurred. The highest relative growth rates were found at 26°C in diets F and FC. The lowest food conversion ratio of 1.12–1.22 (recalculated for dry weight of feed diet) was determined in fish fed diet F at 23°C and 26°C. A high value of condition index appeared to be the early warning of decreasing biological quality of fish and deformities. The lowest incidence of fish with deformities (IDef) was found in groups fed diet C (<1%), while the highest (90%) in fish fed diet F at 26°C. A lower share of dry diet in the fish food and a lower water temperature led to a lower IDef. Thus, amount of dry feed in fish diet was the major factor inducing body deformities, while water temperature only modified the effects of the dietary factor. Diet C at 23–26°C was the most cost‐effective of the tested combinations of diet and temperature.     

Water immersion time reduces the preference of juvenile tropical spiny lobster Panulirus ornatus for pelleted dry feeds and fresh mussel

Development of a pelleted dry feed as an alternative to feeding fresh fishery by‐catch is an environmental priority for tropical spiny lobster aquaculture. Earlier studies have shown the lobster's acceptance of pelleted dry feed diminishes rapidly after immersion in water. In this work, we quantified the rate at which dry matter, total protein, soluble protein and individual and total free amino acids were lost from pieces of green‐lipped mussel Perna canaliculus, a commercially‐extruded Penaeus japonicus (kuruma) shrimp feed (KSF) and four laboratory‐made, fishmeal‐based, pelleted feeds upon immersion for up to 7.5 h. The laboratory‐made feeds contained homogenates of either green‐lipped mussel, polychaete (Marphysa sanguinea), prawn (Metapenaeus bennettae) or squid (Sepioteuthis spp.). After being immersed in water for 0, 2.5 or 5 h, these same feeds were offered as a paired choice with KSF in two preference feeding studies with juvenile Panulirus ornatus lobsters. The loobster's preference for fresh mussel always exceeded that of KSF, irrespective of immersion time. Regression of the proportional intake of test feeds against the relative leach rate of KSF identified soluble protein, glycine and taurine as the principal leachate components having the highest positive correlations with the lobster's feeding preference.     

Optimizing Salting and Smoking of Catfish (Bagre marinus) Using Response Surface Methodology

ABSTRACT

Response surface methodology was used to assess the effects of brine concentration (0.1127–0.2473 g NaCl/g), salting time (49–271 min), smoking temperature (53.2–86.8°C), and smoking time (216–384 min) on moisture content, salt content, yield, taste preference, and texture preference of smoked catfish slices. Optimal process conditions were determined through the graphical method and desirability function approach. The desirability function showed that the optimal conditions for salting and smoking of catfish were: smoking temperature, 70°C; smoking time, 300 min; salting time, varying from 193.39 to 194.68 min; and brine concentration varying from 0.1791 to 0.1797 g NaCl/g. Under optimal conditions, moisture content, salt content, yield, taste preference, and texture preference of smoked catfish were 0.53 g water/g, 0.064 g NaCl/g, 58%, 3.7, and 3.7, respectively.     

Influence of spoilage and processing temperature on the quality of marine fish protein sources for salmonids

Press cake meals were prepared from previously frozen herring immediately following thawing and after storage for 8 or 12 days at 2-5°C. Each of the raw sources of herring was subjected to two processing temperatures, 75°C and 100°C, during meal preparation. Also, protein hydrolysates were prepared using ocean perch when fresh or after storage at 2-5°C for 4 or 8 days. Subsequently, each of the three hydrolysates was dried at 85°C or 93°C. In two separate experiments, each of the herring press cake meals and dried perch protein hydrolysates was blended with a reference diet in a 30:70 ratio (test protein source: reference diet). All diets contained 5 g kg^?1 chromic oxide as an indigestible marker. The reference diet and all test diets were provided to satiation to chinook salmon in salt water and rainbow trout in fresh water, with digestibility of organic matter, protein and energy measured by difference. Digestibility of protein was also measured by the pH-stat and dilute pepsin solubility in vitro techniques. The results indicated that variation in processing temperature to a maximum of 100°C had little effect on digestibility of marine fish protein sources. By contrast, raw material storage for 8 days or more at 2-5°C prior to processing was found to reduce organic matter digestibility and sometimes nitrogen digestibility in salmonids. In vitro measures of digestibility were of little help in predicting the nutritive value of the test protein sources. Cadaverine level in herring press cake meal was shown to be a good indicator of spoilage in the raw material.     

Effect of temperature on the development, growth, survival and settlement of green mussel Perna viridis (Linnaeus, 1758)

The effect of temperature on the development, growth, survival and settlement of Perna viridis was studied under controlled conditions to provide information needed for the development of commercial hatchery technology for green mussel P. viridis. Total mortality of the larvae occurred after 24 h at temperatures of 33°C and 35°C. At 24°C, larvae took longer to settle than at temperatures of 27°C, 29°C and 31°C. For optimum larval development (8–13 h), growth (17.2±0.84 μm day^–1) and survival (55.2±0.84%), a hatchery rearing temperature of 31°C is required. For settlement no significant difference was seen between the percentage settlement at 29°C (49.3±3.34%) and 31°C (45.8±1.76%). However, the process of settlement began and ended earlier at 29°C (from 15 to 18 days) than at 31°C (from 18 to 20 days). Thus for larval settlement a temperature of 29°C is recommended.     

Effect of temperature on digestibility,growth performance and nutrient utilization of corn distiller’s dried grains with soluble (DDGS) in Common carp juveniles

The aim of this trial was to study the digestibility of corn distiller's dried grains with soluble (DDGS) in Common carp juveniles at two water temperatures 20°C and 30°C. DDGS digestibility was determined based on the substitution of 30% of a reference diet by test DDGS. Three hundred and sixty Common carp juveniles (average weight, 40 ± 7 g) were distributed in thermo‐regulated recirculation water system equipped with twelve 1m³ fibreglass tanks (30 fish per tank), which were allotted to four experimental group in triplicates. Half of the experimental groups were maintained at 20°C, whereas the other half were exposed to 30°C. Juveniles reared under different temperature regimes were fed either of the two diets, with or without DDGS (DDGS diet or reference diet), to evaluate the interaction effect between water temperature and nutrient digestibility of corn DDGS in Common carp. Diet and water temperature interaction was effective in modulating the response of dry matter digestibility of DDGS ingredient, and digestibility was found higher in juveniles reared at 20°C compared with 30°C. Growth, feed efficiency and protein efficiency were higher at 20°C compared with 30°C. Whole body csomposition of Common carp juveniles was found unaffected due to diet and water temperature interaction. Overall, it is concluded that digestibility and growth performance of Common carp is better at 20°C compared with 30°C, and DDGS has high potential for inclusion in diets of Common carp.     

Optimization of Hydrolysis Conditions for Production of Gelatin Hydrolysates from Shark Skin Byproduct and Evaluation of Their Antioxidant Activities

ABSTRACT

The effect of Alcalase hydrolysis conditions on antioxidant activities of shark skin gelatin hydrolysate (SSGH) byproduct was studied. Optimal hydrolysis condition for SSGH at 60°C, pH 7.5, and 2.70 AU kg^?1 gelatin protein was used for varied hydrolysis times (10–90 min). The IC₅₀ against DPPH radicals of SSGH hydrolyzed for 90 min (SSGH-90) was 27.39 mg ml^?1, which is greater than ascorbic acid. SSGH-90 was predominantly composed of 15–20 kDa protein fragments that regulated increases in peroxide value and thiobarbituric acid reactive substances values and suppressed decrease in DHA of a fish oil-in-water emulsion during storage at 30°C for 7 days.     

Atkinsiella hamanaensis sp. nov. isolated from cultivated ova of the mangrove crab,Scylla serrata (Forsskål)*

Abstract. Atkinsiella hamanaensis sp. nov. a marine mastigomycete isolated from ova of the mangrove crab, Scylla serrata (Forsskål), is described and illustrated. The fungus grew over a temperature range of 15–32°C, with an optimum of 29–32°C. Its growth was observed in peptone-yeast extract glucose broth containing 1–5% NaCl, with optimum growth at 2–3% NaCl concentration. At 6% or more NaCl concentration, growth was inhibited. Its pH tolerance ranged from 4 to 9.     

Chemical Compositions and Functional Properties of Protein Isolated from By-Product of Triangle Shell Pearl Mussel Hyriopsis cumingii

Hyriopsis cumingii is a freshwater mussel widely cultured in China to produce cultured pearls. However, after the pearls are harvested, the mussel is discarded. To make effective utilization of pearl production wastes, proteins were recovered from the pearl mussel meat using pH shift technology. The protein recovery conditions, chemical compositions, and functional properties of the recovered protein were investigated. Results show that the proteins could be well extracted from the meat by 5 volumes of alkali water (pH 11, 20°C, 1 h) followed by acidic precipitation (pH 5.2). The recovered product contained 94.7% of protein with high levels of essential and semiessential amino acids (48.9%). The most abundant essential amino acid was sulfur-containing amino acids (12.82%), followed by lysine (8.89%), phenylalanine (4.69%), and threonine (4.37%). Compared with soybean protein isolate and egg protein, the recovered protein had better water/oil absorption capability, better foaming ability, and similar emulsion capability. These results suggest that the protein isolated from the pearl mussel meat might be utilized as ingredients for the food industries.     

Global Diversity of Aquatic Food Products

In this work, water activity (a_w), moisture loss, and salt uptake as mass transfer in osmotic dehydration (OD) of Cyprinus carpio fillets were analyzed. Two highly concentrated solutions were used for the OD: binary (NaCl-water) and ternary (NaCl-sucrose-water) solutions at 20°C. Both solutions had the same NaCl concentration, but the second also had sucrose (2:1) which improved water loss and reduced NaCl gain. Among the OD models analyzed, Peleg's equation presented the best fit with the ternary solution (R² > 0.900), while the Zugarramurdi and Lupín did so for the binary solution treatment (R² > 0.950). Page's model presented good fit for water release in both cases (R² > 0.950).