Abstract:Cytochrome P450s （CYPs） is the most important enzyme for drug metabolism in animals. Inappropriate coadministration often causes treatment failure in fisheries owing to induction of CYP activity. However, limited information is available about CYP induction in fish. In order to supply useful information on CYP induction, the present study assessed the effects of fish specific CYP inducers on difloxacin （DIF） metabolism and the enzyme kinetics in kidney cell of grass carp （Ctenopharyngodon idellus） （CIK） by reversedphase highperformance liquid chromatography （RP-HPLC）. The enzymatic equations of control and groups induced by β-naphthoflavone （BNF）were 1/V= 0.137 5 ×1/［S］+0.003 and 1/V=0.024 5×1/［S］+0.001 3. Results demonstrated that the amounts of DIF metabolism were increased by 1 fold and enzymatic parameters Clint and V_max of DIF metabolism were significantly increased by 7 and 2 folds due to BNF pretreatment. BNF is the specific inducer of CYP1A in fish. Therefore, CYP1A may be responsible for DIF metabolism. This study provides instructive information to ensure treatment success in fisheries medication with two or more drugs.

Abstract:The aim of the study was to investigate the estrogenic effects of octylphenol (OP) on carp (Cyprinus carpio). Vitellogenin (Vtg) and the parameters of growth and development were determined as biomarkers. The oneyearold carp from a large reservoir were kept in the laboratory for 7 days. Then they were exposed to OP under semistatic conditions for 32 days. They were fed once a day. The water temperature was （18±1） ℃ during the experiment. Five concentrations of OP at 10, 50,100,300 and 500 μg/L were selected for this study. The mortality, abnormal behavior and appearance of the carp were recorded during the exposure. At the end of the exposure, fish were sampled to measure body weight, body length and gonadal weight, then plasma and liver homogenates were prepared for the determination of Vtg concentration by ELISA. The data were analysed with SPSS 11.5. At the end of exposure, it was found that there was no significant difference in the survival and growth of the fish. The exposure to OP caused obvious changes in gonadosomatic index (GSI). In accordance with the increase of the OP concentration, the GSIs of female carp increased, while that of male carp decreased. OP at 10 μg/L caused the GSIs of male carp decreased significantly (P＜0.05). The GSIs of female carp increased significantly when the OP concentration reached 50 μg/L (P＜0.05). OP induced the synthesis of Vtg in male carp. Vtg was not detected in plasma or liver homogenates in control groups, and it was detected in some of the samples in 10 μg/L group. The Vtg levels increased greatly when the OP concentration reached 50 μg/L (P＜0.05). The Vtg levels in 500 μg/L group were significantly lower than those in 300 μg/L (P＜0.01), but significantly higher than those in 100 μg/L group (P＜0.01). The results indicated that octylphenol (OP) has obvious impact on the gonadal development of carps. It can induce Vtg synthesis in male carps. OP has visible estrogenic effects on carp (Cyprinus carpio) although it did not affect the growth of the fish at low exposure concentrations.

Abstract:Crustacean is one of the eight kinds of allergen sources in coastal areas, which causes the IgEmediated hypersensitive reactions with clinical manifestations including urticaria, angioedema, asthma, and even fatal anaphylaxis. Tropomyosin (TM) is the major allergen of decapod crustaceans with highly conserved amino acid sequences. The purpose of this study is to confirm whether TM is a major crossreactive allergen in mantis shrimp (Squilla oratoria) which is taxonomically distinct from decapods and largely consumed as a delicacy in China. Quantification of TM in different species of crustaceans was also conducted. Muscle sample from mantis shrimp was homogenized with phosphate buffer to prepare heated extracts and separated by 12 % sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDSPAGE). A protein band with molecular mass of about 36 ku was detected by IgEimmunoblotting by all of the sera with crustacean allergy, suggesting it is the major allergen of mantis shrimp. This protein was further purified to homogeneity by acetone powder preparation, isoelectric point precipitation, ammonium sulfate fractionation (40%-60% saturation), and heat treatment. Purified protein was demonstrated to be TM by Western blot using polyclonal antibody against TM from Chinese mitten crab (Eriocheir sinensis). Heated extracts from other crustaceans including mud crab (Scylla serrata), Pacific white shrimp (Penaeus vannamei) and short necked clam (Venerupis variegata) were also prepared, and the crossreactivity of TM from mantis shrimp with TMs from these crustaceans was confirmed by inhibition immunoblotting using polyclonal antibody against TM and inhibition ELISA using sera with crustacean allergy. Quantification by ELISA using polyclonal antibody against TM revealed that TM content in mantis shrimp muscle is much lower than that in Pacific white shrimp and mud crab muscle, which was about 45 times lower in mantis shrimp muscle than that in Pacific white shrimp muscle. However, its allergenicity seems equivalent to other decapod crustaceans as showed by inhibition ELISA using sera with crustacean allergy. This may be due to the degradation of TM in mantis shrimp by its endogenous serine proteinases and cathepsins which destroyed the IgGbinding epitope but not the IgEbinding epitopes. In conclusion, this study demonstrated that allergenicity of mantis shrimp is almost equivalent to decapods and TM is the major allergen in mantis shrimp with high crossreactivity to decapod crustaceans.

Abstract:Ruditapes philippinarum has a widespread consumption in China. It is enjoyed for the uniqueness of its flavour and has a wide variety of applications in foods, such as soup and flavouring. Associated with the diversiform consumption of Ruditapes philippinarum is the general increase of allergic disorder. To provide guarantee for the allergy sufferers, it is important to establish a more convenient method for the detection of food allergen. A visible antibody microarray for detecting Ruditapes philippinarum allergen was developed in this study, which was based on the 3, 3′, 5, 5′Tetramethylbenzidine (TMB)H₂O₂ reaction catalyzed by horseradish peroxidase (HRP). Several physicochemical parameters such as the incubation time and the dilution ratio of antibodies were optimized. A modified sandwich reaction was performed with immobilization of rabbitanti-Ruditapes philippinarum antibody onto the threedimensional slide, followed by adding antigen，mouseanti-Ruditapes philippinarum，HRPgoatanti-mouse IgG. After incubating, TMB was employed to give signals, the slides were observed by naked eyes and recorded with flatbed scanner, analysed with GenePix Pro 6.0. The results showed that allergen from Ruditapes philippinarum can be detected sensitively with a sensitivity of 10 ng/mL. The method has good reproducibility with average intraassay CV of 5.9% and average interassay CV of 10.3%. The recoveries of three different spiked concentrations in sausage and surimi stick ranged from 73.54% to 95.44%. During storage at 4 ℃, the activity of the chips kept stable for 4 months. Moreover, some crossreactivity with Penaeus vannamei was found. With visible and stable results, this method has shown great potential in the massive parallel analysis of various food allergens simultaneously.

Abstract:HPLC analysis for paralytic shellfish poison (PSP) in shellfish foods has now become a current method in the world, in which PSP standard is necessary. Unfortunately, commercial PSP standard has now become difficult for handling in china, as some purification technique of PSP has not been still breached, and the PSP substance has now been recognized into the list of chemical weapons. Preparing independently some PSP standard is necessary and will be a good way for solving the standard substance problem in china.  In this paper, extraction and purification of PSP was discussed, using a poisoned scallop sample as a material. The total toxicity of the crude PSP extract solution was 6 170 MU, while using acid 80% ethanol as an extractant. From the crude extract, PSP was purified via ultrafiltration, Bio-Gel P-2 column chromatography and BioRex 70 column chromatography, and a purified toxin with amount of 2 100 MU was obtained. The result of chromatography showed the toxin mainly contained gonyautoxin group (GTX1-4). HPLC analysis showed that all of the peaks is very sharp and clear, in which the ratio of GTX1, GTX2, GTX3 and GTX4 was 2∶4∶14∶1 (calculated as the ratio of peak area on HPLC), indicating that GTX3 is the major PSP composition in the poisoned scallop sample, and the purified toxin is available using as a standard for HPLC analysis. From the results of experiments, the technique for preparing PSP standard is effective and successful. In the other hand, the stability of the purified toxin was discussed, through comparing the HPLC analysis between the native toxin and that of the one treated with 0.1 mol/L HCl.

Abstract:The objective of this study was to evaluate the effect of ultrahigh pressure (UHP) treatment on gel properties of Collichthys lucidus surimi. Three factors of UHP treatment which were pressure, time and temperature were investigated. The textural parameters such as hardness, springiness, cohesiveness, chewiness and gel strength of surimi gel were obtained by texture analyzer. With the gel strength as index, the optimum UHP treatment process was optimized with orthogonal test as follows: pressure of 300 MPa, time of 15 min, temperature of 20 ℃ and under the above conditions, the gel strength was 363.15 g·cm. It was found that surimi formed gelation at 200 MPa, gel properties had no significant difference when UHP time was more than 5 min, and as UHP temperature increased, gel properties decreased significantly. The effect order of UHP treatment conditions on gel strength was pressure>temperature>time. When pressure was higher than 300 MPa and time was more than 5 min, gel cohesiveness had no significant difference under those conditions. Cohesiveness decreased significantly with the increasing temperature when the temperature was higher than 20 ℃.Compared with heat treatment, we found that the gel strength of surimi by UHP treatment was better than heat treatment, was 2.2 times of heat treatment. But the hardness under UHP treatment was lower, only 67% of heat treatment. As for the springiness, cohesiveness, chewiness, water holding capability and whiteness, the effects of UHP treatment were better, the springiness was 1.6 times of heat treatment, particularly. From the two cooperative processing methods of UHP and heat treatment, it showed that the effect of heat treatment after UHP was similar to the twostage heat treatment while UHP treatment after heat treatment could damage gel structure obviously. Those results indicated that UHP treatment had an effect on the formation of surimi gel. UHP treatment could modify the quality of processed musclebased products. This study suggested that UHP treatment exhibits a potential for surimi processing.

Abstract:Yessotoxin(YTX) and its analogues are disulfated polyether compounds which have been concerned more in seafood quality monitoring and shellfish industries recently. Many studies on the toxicity of YTXs had been carried out, but the results showed apparent discrepancies. Just these discrepancies have encouraged many researchers to study the mechanism by which YTX exerts its action, such as what the target tissues are, what the pattern of the mode and precise mechanism of action are. However, the process still remains largely unclear. This paper aims to study the toxicity of yessotoxin and analyze the possible action mechanism to the nerve tissue by using histological and immunohistochemical methods. 24 hrs after tail intravenous injection with yessotoxin, the female ICR mice were killed and cerebella tissue was fixed and sliced. Hematoxylineosin（HE）staining used to study the effects of yessotoxin on nerve cells shows obvious morphological changes of Purkinji cells in cerebella tissue, such as shrinkage, deep staining of cytoplasm, nonmottled Nissl’s body and so on. According to the immunohistochemical staining of calcium binding protein S₁₀₀, there is a more positive response to YTX in test group than in control group. It seems that YTX induces the increase of Ca²⁺ concentration in Purkinji cells of mice cerebellum; it is identical to the results of other researches. To our knowledge, this is the first report of the toxicity of YTX on nervous system in China, but the work is preliminary and further studies are needed, such as the relationship between the action mechanism of YTX and Ca²⁺ signal transduction.

Abstract:Studies of cathepsin L in the surimi of Southern blue whiting HU Ya-qin, YAO Yan-jia (School of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, 310029, China) Abstract: According to the conventional method, actomyosin was extracted from the surimi of southern blue whiting (Micromesistius australias). After Sepharose 6B gel filtration of the actomyosin obtained, cathepsin L activity was monitored in each of the fractions collected. The results showed that the activity values in the actomyosin samples were much higher than that in the washing water, suggesting that cathepsin L could not be removed completely during conventional leaching and still remained in actomyosin sample. Further purification of actomyosin by dilution-precipitation could not remove cathepsin L effectively, indicating that cathepsin L might be dissolved together with actomyosin in the presence of high ion-strength solutions. The profile of the gel filtration showed hat the main peak of cathepsin L was obviously separated from that of actomyosin, suggesting that cathepsin L was non-binding with actomyosin. Fractions that showing the main peak of cathepsin L were pooled to be called Lmix, partially purified cathepsin L. Lmix could strongly hydrolyze Z-Phe-Arg-MCA, a specific substrate for cathepsin L, rather than Z-Arg-Arg-MCA, spcefic substrate for cathepsin B, nor Arg-MCA, substrate for cathepsin H, as well as Boc-Gln-Ala-Arg-MCA, substrate for trypsin and trypsin-like proteases. The above results indicate that Lmix was a crude cathepsin L. Cathepsin L specific inhibitors, such as E-64, specific inhibitor for cathepsins, and leupeptin, inhibitor for both cathepsins and trypsin-like proteases, could suppress the activity of Lmix completely. Activators for cathepsin L, such as DTT, EDTA+DTT, could effectively improve the activity of Lmix. As a result, the effect of activators and inhibitors confirmed the partially purified crude enzyme, Lmix, to be a thiol-type cysteine protease. The temperature dependence and pH dependence of the activity of Lmix were also investigated. Lmix had optimum temperature of 45℃ which was right in the temperature range of modori phenomena. Lmix had optimum pH of 5.5 but kept high residue activity near neutral pH, the pH range of surimi processing, suggesting its high potential ability in modori phenomena. Key words: Southern blue whiting; cathepsin L; leaching; inhibitor

Abstract:In the previous study, we reported that two types of myosin heavy chain isoform genes were isolated from fast skeletal muscles of silver carp(Hypophthalmichthys molitrix) acclimatized in winter and summer, and named the low temperature-type(sc-w) and the high temperature-type(sc-s), respectively. In this study, two genespecific reverse primers were designed according to the striking differences in the nucleotide sequences of 3′terminals between the two types of silver carp myosin heavy chain isoform, and a forward primer was designed with reference to conserved nucleotide sequences in 5′terminal of cyprinidae. Long-PCR was performed to amplify the complete cDNAs encoding myosin subfragment-1(S1) heavy chains for the two types of isoform. DNA sequencing of both strands was carried out, and the amino acid sequences for the two types of myosin S1 heavy chain were deduced. The results showed that the primary structure of myosin S1 heavy chain produced 80.5% identity between sc-w and sc-s. Whereas a high sequence identity of 97.2% was found between sc-w and gc10, which was reported to be isolated from 10 ℃acclimated grass carp. In contrast, the amino acid sequence of S1 heavy chain for sc-s revealed much higher identity to those of gcI(98.4%) and gc30(97.1%), which were isolated from 30 ℃acclimated grass carp. Compared with the other myosin S1 heavy chain isoforms, isoformspecific differences for sc-w and gc10 were clearly observed in 43 amino acid residues. Furthermore, among these amino acid mutations, 15 mutations occurred at the conserved residue sites. Additionally, sc-w and gc10 showed striking differences compared with the other S1 heavy chain isoforms in the two surface loops, loop 1 located near the ATPbinding domain and loop 2, which is one of the actin binding domains, suggesting that the changes in the flexibility of two surface loops were caused by modulations in length, amino acid composition and charge can play an important role in adaptation of motor function to low environmental temperature. Phylogenetic analysis further demonstrated the effects of environmental temperature on genomic divergence and functional evolution of fish myosin isoforms.

Abstract:Chitosan was applied to surimibased products prepared from silver carp and the effects of chitosan with different degrees of deacetylation(DD), molecular weights(M_W) and adding amounts on the gelling properties of surimibased products were investigated. The gel strength, texture profile analysis(TPA), water loss rate and color were used as assay indicators. Also, the microstructure of the gels was analyzed with scanning electron microscopy. The results showed that addition of chitosan with 64% DD resulted in significant increases in both texture properties and waterbinding capacity. The gel strength increased approximately by 34% and water loss rate decreased by 29.1%. Chitosan with different MW had no significant effects on the gel strength. The gelling properties of surimibased products increased proportionally to the amount of chitosan added up to 1% (P<0.05). Samples added with 1.0% chitosan had similar gel strength with samples added with 4.0%starch. Scanning electron microscopy indicated that chitosan could facilitate surimibased products forming gel network. The above results showed that chitosan was a good qualityenhancing agent for surimibased products, which could be used in practical applications.

Abstract:Nile tilapia (Oreochromis niloticus) aquaculture is expanding throughout the world, most notably in China. According to the statistics of FAO, annual China’s production of tilapia by 2008 had risen to nearly 1.2 million tons, which accounts for about 50% of tilapia production in the world. During processing of tilapia to fillets, large quantities of the byproducts such as skin are produced. On one hand, collagen contents in tilapia skins are rich. On the other hand, the bovine spongiform encephalopathy (BSE) episode, as well as religious concerns, has led to intensive research to identify and develop alternatives to mammalderived gelatin. Therefore, tilapia skin can be a good resource of extracting gelatin. However, gelatin extraction from tilapia skin usually had a strong fishy odour, which would limit its utilization. In order to be applied to food and pharmaceutical industries, some methods must be adopted to make the gelatin odorless. In the present study, methods of active carbon absorption, yeast and lactobacillus fermentation were used to remove fishy odour in the gelatin, in which their roles to diminish fishy odour were compared with each other by sensory analysis. And the effects of active carbon absorption conditions on the transmittance and sensory scores of the gelatin solution were studied by orthogonal experiments. After removing fishy odour, the physicochemical properties of the gelatin were studied and its volatile components were evaluated by simultaneous distillationextraction (SDE) and gas chromatographymass spectrometry (GC-MS). Sensory analysis showed that the effects of fishy odour removal of gelatin were significantly different among methods of active carbon absorption, yeast and lactobacillus fermentation (P<0.05). Among these methods, the best one was active carbon absorption. The results of orthogonal experiment indicated that the optimal conditions were the ratio of active carbon addition to 5% (w/v) gelatin solution 1.5% (w/v), and incubated at 40 ℃ for 30 min. After removal treatment, fishy odour in the tilapia skin gelatin was barely detectable. The content of crude protein in the gelatin was 91.3% and its gel strength was high up to 301 g. The transmittance of the tilapia skin gelatin solution was higher than before treatment, and the content of waterundissolved matter was diminished. A total of 33 volatile components in tilapia skin gelatin solution before removing fishy odour were detected by simultaneous distillationextraction (SDE) and gas chromatographymass spectrometry (GC-MS). The volatile compounds of the gelatin solution were predominantly esters, followed by alcohols, ketones and olefines. After removing fishy odour, a total of volatile components in gelatin solution have been diminished to 26 kinds, which were mainly olefines and ketones. The research shows that active carbon absorption appears as a suitable technique to remove fishy odour in tilapia skin gelatin and to improve their physicochemical properties. So, it can be used for industrial production of fishy odour free tilapia skin gelatin.

Abstract:The utilization potential of soybean meal as an alternative protein source for fish meal in practical diets for the juvenile Japanese flounder (Paralichthys olivaceus) was assessed in the present study. Four isonitrogenous and isolipidic diets were formulated to contain 47% protein and 9% lipid. The animalplant protein ratios (A/P ratio) in the diets, representing 4∶1(D1), 3∶1(D2), 2∶1(D3) and 1∶1(D4), respectively, were calculated by adjustment of supplementing proportion of fish meal (FM) and soybean meal (SBM). Two hundred and forty Japanese flounder with an initial average body weight of （13.22±0.02） g were randomly assigned into twelve 900liter tanks equipped with a flowthrough seawater system. Each diet was randomly allocated to triplicate groups of twenty fish each. The fish were fed the test diets twice a day at a daily feeding rate of 2%-3% body weight for 56 days. At the end of the feeding trial, the fish were weighed by batch for the determination of weight gain rate (WGR), feed conversion ratio (FCR) and protein efficiency ratio (PER), and then five fish from each tank were randomly sampled and pooled by tank for the analysis of proximate composition in the whole body. Another five fish from each tank were randomly selected to collect serum and liver samples for the analysis of blood urea nitrogen (BUN), glutamicpyruvic transaminase (GPT), glutamicoxalacetic transaminase (GOT), free fatty acids (FFA), total protein (TP), triglyceride (TG), cholesterol (CHO), highdensity lipoprotein cholesterol (HDL-C), and lowdensity lipoprotein cholesterol (LDL-C). WGR, PER, and SGR of Japanese flounder decreased, while FCR increased with increasing SBM ratio in diets, and significant differences for the parameters were found when SBM ratio in diets increased to upon 24% (P<0.05); HSI followed the same pattern as WGR, and the values in D1 group were significantly lower than those of other groups (P<0.05). The values of CF were not different among dietary treatments (P>0.05). There were no significant differences in whole body moisture, crude protein, and ash content of the fish among dietary treatments, however, crude lipid content decreased as SBM ratio increased, and the values of D3 and D4 groups were significantly lower than that of D1 group. There was a tendency of marginal increased BUN content in serum and TP content in liver of the Japanese flounder with increased SBM ratio in diets, whereas the opposite trend is true for GOT, GPT activity in serum, and FFA conten in liver (P>0.05)；TP and HDLC content in serum (P<0.05). Serum TG and liver TG content increased significantly while the A/P ratio decreased to below 2∶1 (P<0.05); serum CHO, serum LDL-C and liver CHO content of D1 group were significantly lower than those of other groups (P<0.05). These results indicate that higher ratio replacement FM by SBM (D3 and D4) in diets could adversely affect the growth and protein and lipid metabolism of Japanese flounder, and the optimal SBM ratio in diets was 16% based on the results of growth performance, body composition, protein and fat metabolism indices, and cost of weight gain in the present study.

Abstract:Tilapia intestines as enzyme raw materials are studied systematically by ultrasonic extraction technology of auxiliary, electrophoresis, chromatography techniques and so on for the first time. The results showed that: after organic mashing and ultrasoundassisted extracting, 30％－70% of ammonium sulfate fractions, QFF anion chromatography and Sephedax G-100 gel chromatography, the purified protease from tilapia intestines was obtained. The purified protease specific activity is 335 U/mg and yield is 32.8%. The result of SDSPAGE showed a single band and the subunit molecular weight of tilapia intestines protease was 28 ku. The protease optimum pH value and temperature are 8.0－8.5 and 37－42 ℃ respectively. It is stable at pH range from 7.0 to 9.0 and has good thermal stability. Enzyme K_m value and V_maxvalue are 0.605 g/L and 9.407 μg/min. Ag⁺ and Pb²⁺ can inhibit the enzymatic activity completely while Na⁺ and K⁺ without inhibition. PMSF can strongly inhibit the activity of the enzyme. Pepstatin A and urea partly inhibit the activity of the enzyme. EDTA has no effect on the enzyme while DTT can activate the enzyme activity. The protease from tilapia intestines is a kind of serine protease. Further work should be carried out on the sequences of the enzyme and its applications．

Abstract:Grass carp(mean body weight 19.46±0.04 g) were first fed for 60 days by three modes(mode A, grass carp were fed basal diet without chitosan; mode B, grass carp were fed experimental diet, supplemented with 0.5% chitosan in basal diet; mode C, grass carp were first fed experimental diet and then basal diet at an interval of 15 days) and then starved for 15 days. Growth index, nitrogen oxide(NO) content and lysozyme(LSZ) activity in headkidney(HK),spleen,hepatopancreas and serum were measured to investigate effects of feeding modes of chitosan on prevention of starvation of grass carp. The results showed that length gain and weight gain of grass carp at the end of 60 days feeding were significantly higher in modes B and C than those of the control(（P<0.05) and were the similar variation(（P＞0.05) after 15 days starvation, regardless of feeding or starvation. NO content,in HK and hepatopancreas, and LSZ activity, in HK and serum, were significantly higher in starvation treat in mode A. On the contrary, NO content ,except in HK, and LSZ activity or NO content, except in spleen, and LSZ activity, except in hepatopancreas, were significantly lower(（P<0.05) in starvation treat or had no statistical significance(（P＞0.05) between starvation and feeding treats in modes B and C.Obviously, starvation caused various influence in different tissues and effects caused by different oral administration treats were dissimilar on prevention of starvation of grass carp. Comparatively, modes B and C had an effective resistance to starvation stress, but there was no statistical significance in both of them. Given economical efficiency and practicability, chitosan by incontinuous feeding will be suggested to promote growth and lighten the stress caused by starvation.

Abstract:At present, more plant protein feedstuffs are used in aquatic feeds for the shortage and the increasing price of fish meal. The deficiencies of some essential amino acids (EAA) in plant protein feedstuffs lead to the addition of some EAA to balance diet composition. However, the effect of supplementing crystalline EAA was not positive for some fishes. As a result, the present experiment was conducted to investigate the effect of crystalline or microcapsuled lysine supplementation into practical diets on growth performance, and the total plasma free amino acids content of grass carp Ctenopharyngodon idellus. Four diets were prepared, which were high soybean meal（SM）diet with 23% SM, low SM diet with 15% SM, low SM diet added with crystalline or microcapsuled lysine, which had the same lysine content as high SM diet respectively. Grass carp (49.0±2.0) g were fed the four diets with triplicate for 8 weeks. Growth rates(GR) of the four groups were 279.3%, 239.7%, 245.6%, 277.5%, feed coefficient(FC) were 1.62, 1.88, 1.85, 1.64, respectively. Compared with low SM group, adding crystalline lysine in diet had no significant effects on growth performance, but the growth rate was improved by 15.8% and FC decreased by 0.24 (P<0.05) by adding microcapsuled lysine in diet. Fish fed on low SM added with microcapsuled lysine had the same GR and FC as those of high SM group(P>0.05). Plasma total free amino acids(TFAA) concentration at 0, 1, 2, 3, 4, 5 h after feeding were determined, and the highest concentration of TFAA occurred at 3 h after feeding for high SM diet, low SM diet added without or with microcapsuled lysine, but absorbing peak occurred at 2 h after feeding for low SM diet added with crystalline lysine, which means the absorbing peak was advanced. Leaching loss of crystalline and microcapsuled lysine were 69.82% and 19.81%, which indicated leaching loss of crystalline lysine was significantly decreased by microcapsuling. Results above showed that grass carp fed with diet supplemented with microcapsuled lysine had a slower absorbing peak of serum TFAA than that fed with crystalline lysine. Microcapsuled lysine had a lower leaching loss in water than crystalline lysine. Growth rate of grass carp could be improved, FC decreased by adding microcapsuled lysine in low SM practical diet, but was not affected by crystalline lysine.

Abstract:In this paper, an application of the electronic nose was used to evaluate the freshness quality difference of the pomfret（Pampus argenteus） fillet under different storage periods and storage temperatures. The raw data of the pomfret fillet of the electronic nose analysis was analyzed by principal compounds analysis (PCA) and discriminate factorial analysis (DFA). The Q₁₀ model of the pomfret fillet by applying both chemical assays and olfactometric (e-nose) method was developed. The result showed that the sample stored at 273 K, 283 K and 293 K could be well discriminated by 18 Metal Oxide Sensors. Changes in total volatile basenitrogen (TVBN) and total viable count (TVC) of pomfret fillet with respect to different storage time and temperature conformed to the first kinetic model with high regression coefficients(R²>0.95). Using PCA and DFA analysis of Alphasoft11.0 and Arrhenius kinetic model, the Q₁₀ （273-283 K）and Q₁₀（283-293 K） model of shelf-life of pomfret fillet was SL_{(275~283 K)}=3×3.008^(283－T)/10 and SL_{(283~293 K)}=1.5×3.423^(293－T)/10. It was shown from the reliability assessment between predictive and observed shelf-life that relative error was within 10% calculated by the prediction model for the shelflife of pomfret fillet. The remaining shelf-life of pomfret fillet could be predicted at the storage temperature from 273 K to 283 K and 283 K to 293 K based on the Q10（273-283 K）and Q10（283-293 K） model.

Abstract:This experiment was conducted to study growth performance of juvenile zander［initial average weight（7.75±1.17） g］fed five formulated diets with different lipid(energy) to protein ratios.The results showed：The specific growth ratio［SGR (2.86±0.17)%/d］,feed coefficient ratio(FCR 1.57±0.12),protein deposit ratio(PDR 98.44%±2.38%),energy retention ratio(ERR 30.88%±3.83%) performed the best in group 4 after being fed the different diets；Using the secondorder polynomial regression analysis, the optimum protein，the optimum lipid，the optimum gross energy(GE)，the optimum lipid to protein ratio(L/P) and the optimum energy to protein ratio(E/P) in diets for juvenile zander (Lucioperca lucioperca) were estimated based on SGR, PDR and ERR of the juveniles. When SGR was the highest, the optimum protein, the optimum lipid, GE, L/P and E/P were estimated to be 39.80%,8.79%,18.53 MJ/kg,0.22,46.56 kJ/g；When PDR was the highest, the optimum protein, the optimum lipid,GE,L/P and E/P were estimated to be 38.76%,9.18%,18.65 MJ/kg, 0.24, 48.12 kJ/g；When ERR was the highest, the optimum protein, the optimum lipid, GE, L/P and E/P were estimated to be 38.55%,9.45%,18.72 MJ/kg, 0.25, 48.56 kJ/g；The requirement for protein used for energy is decreased when dietary lipid level increases.It was suggested that dietary lipid had significant proteinsparing effect on this fish. But zander (Lucioperca lucioperca) utilizes the lipid definitely；When E/P was as high as 58.79 kJ/g or as low as 42.54 kJ/g，WGR，PDR and ERR were significantly lower,FCE was significantly higher(P<0.05) than other E/P levels，indicating that diets with too high E/P level or low E/P level would inhibit the growth and feed utilization of juvenile zander.

Abstract:The objective of this study was to assess the control on formation of formaldehyde (FA) during the heating processing in jumbo squid by compound inhibitors. The substances inhibiting the formation of FA were selected in the squid, and the property of inhibitors to reduce FA was analyzed. The compound inhibitors was optimized by single factor experiment and orthogonal experiment. The results showed that the amount of FA decreaed significantly in the squid treated by citric acid (CA), CaCl₂, MgCl₂, tea polyphenolic (TP), mulberry flavonoids (MF), whereas, it increased greatly treated by Na₂SO₃, Fe²⁺ in presence of the reductants of cysteine and ascorbate. The low concentration of inhibitors, CA, CaCl₂ and TP, could reduce more than 90% of the amount of FA in supernatant of squid, and the optimal inhibiting concentrations were 10 mmol/L, 10 mmol/L and 0.1%, respectively. The thermal decomposition of trimethylamineN-oxide (TMAO) to FA, dimethylamine (DMA) and trimethylamine (TMA) was significantly inhibited by CA, CaCl₂, MgCl₂, while, the amount of FA could be reacted effectively by TP and MP in the squid at high temperature. Then the amount of FA and DMA dropped significantly, and the content of protein was not affected for the squid slice treated by the optimal compound inhibitors, 0.04% TP and 10 mmol/L CaCl₂. Therefore, the compound inhibitors of FA have a potential application in the control of the amount of FA in squid processing.

Abstract:To investigate the compensatory growth responses of the scavenging gastropod Babylonia areolata, a refeeding after starvation study was performed at （25.8±1.7） ℃. Juvenile spotted ivory shells weighing a mean of 5.25 g were starved for 7 (S7), 15 (S15), 25 (S25), and 40 (S40) days, respectively, and then fed to satiation once a day during the 30 days refed period. The four corresponding control groups were fed to satiation during the experiment. Three tanks each containing 30 snails made up a group. The results indicated that the water contents of the whole soft body increased gradually during starvation, and was significantly higher than that of the control when the snails were fasted for 15 days (P<0.05). The lipid and glycogen contents were significantly lower than those of the controls when food were prohibited for 15 days and 25 days respectively (P<0.05), while there were no significant differences in protein contents (P>0.05). The ratios of RNA/DNA in foot muscle and hepatopancreas of the snails both decreased gradually during the fasting period. After 30 days recovery growth, except for the water content in the S40 group, which was significantly higher than that of the control (P<0.05), there were no significant differences in other biochemical composition between refed and control groups(P>0.05). The ratios of RNA/DNA were near or markedly higher than that of the control except in hepatopancreas of the S40 group which was lower than that of the control (P<0.05). The feeding rate (FR) during refed period was higher (for S7, S15) or significantly higher (for S25, S40) than that of the controls which were fed throughout the experiment, there were no significant differences in food conversion efficiency (FCE) and increments of body weight between the S7, S15, S25 groups and their controls respectively, as well as no significant differences were found between the S7, S25 groups and the controls respectively as to specific growth rate (SGR) (P>0.05), while the SGR was markedly higher than that of the control in the S15 group (P<0.05). Whereas there were significant decreases in the FCE, SGR and increment of body weight for the S40 group, although the FR of this group was greatly increased compared to the control (P<0.05). In conclusion, the snails could utilize lipid and glycogen first as energy resource when being deprived of food, and there is complete compensatory growth in snails as the starvation period was no more than 25 days. The results of the present study indicate that prolonging the feeding intervals properly can facilitate the culture manipulation and spare food under the premise of not affecting the growth rate of the snails, and the RNA/DNA ratios in the two tissues are a valid indicator of nutritional condition in spotted babylon juveniles.

Abstract:With China’s increasing development of fisheries and aquaculture, there is an annual increase in the manufacture of aquatic products. Processing of aquatic products is associated with a large amount of waste products, in which fishbone and fishhead account for 45%. The waste products had been used as material of fish sauce and hydrolyzed protein, which companied with high cost and complicated processes. How to efficiently utilize this kind of calcium source becomes focus in fish deep processing. Not only in China calcium deficiency is a prevalent nutritional disease, it has attracted the attention of the world because its serious result. The lack of calcium intake leads to great interests in demand of calcium supplement and calcium fortification. Fishbone is a kind of natural calcium source. Till now, researches on utilization of fishbone almost focused on freshwater fish, no research on seawater fish were conducted to study biological effects on calcium supplement and bone fortification. So, to investigate the possible use of waste products obtained after processing haddock, the present study prepared haddock bone calcium powder by NaOH and ethanol soaking (alkaline-alcohol method) and prepared haddock bone calcium tablets using the powder in combination with appropriate excipients. The biological efficacy of the haddock bone calcium tablets was investigated using Wistar rats as an experiment model. Results showed that the optimal parameters for the alkaline-alcohol method are as follows: NaOH concentration 1 mol/L, immersion time 30 h, ethanol concentration 60%, immersion time 15 h. The fish powder processed in this way has high quality in color and odor when compared with that prepared in acid method. Contents of fishbone powder are as follows: calcium 27.8%, phosphors 12.2%, protein3.67%, fat 0.44%. A mixture of 4% polyvinylpyrrolidone in ethanol was used as an excipient, the ratio between full-cream milk powder and filler was 1:2. Under these conditions, there is no necessity in the use of a disintegrating agent for disintegrating time is less than 12 min. This process provided satisfactory characters for tablets in terms of rigidity and taste. Animal studies showed that the haddock bone calcium tablets at a dose of 2g/kg/d or 5g/kg/d significantly increased blood calcium and phosphorus levels and bone calcium content in Wistar rats. Therefore, the haddock bone calcium tablets have a better biological efficacy than the traditional calcium carbonate formulation and promote bone growth, increase bone density and prevent osteoporosis. The absorption rate is crucial for nutrients. High absorption rates are usually directly related to the bioactivity of the nutrient. Although the reasons of high absorption in the rats fed with haddock bone calcium tablets are still unclear, it is suggested that there are some factors, such as treatment with method of alkaline-alcohol or the vitamin D in the added milk, may play positive roles in increasing absorption ratio. Some natural trace elements such as magnesium, iron and phosphorus may also be responsible for the high bioavailability of calcium derived from haddock fishbone relative to calcium carbonate. These researches provide a more effective way for economically utilization of fish bone derived from marine fish processing.

Abstract:Prawn is widely popular because of its nutrition and delicacy. The technology and scale of prawn aquaculture developed rapidly with high economic value. The prosperity of production and marketing grow continuously. Frozen storage, including frozen prawn, is widely used as a good method of preservation and processing. However, characteristics of prawn frozen storage and the impact on prawn quality had not been deeply studied yet. Three kinds of cultured prawn, dominanted in market, were chosen as study objects, and the salt solubility of myofibrillar, Ca²⁺-ATPase activity and sulfhydryl content were chosen for research indicators. The changes of the biochemical characteristics of prawn protein were investigated and the impact of different temperatures on quality of prawn was evaluated when stored at -10 ℃,-20 ℃,-30 ℃,-40 ℃ respectively. There are some differences among the three indicators of protein denaturation when applied to prawn. Ca²⁺-ATPase activity is the most sensitive. It can reflect different levels of protein frozen denaturation caused by different temperatures from -10 ℃ to -40 ℃. Different levels of protein frozen denaturation can also be reflected by the salt solubility of myofibrillar above -20 ℃ refrigeration. The salt solubility of myofibrillar decreased obviously at -10 ℃, but the trend declined below -20 ℃, and no significant difference was observed at -20,-30 and -40 ℃. The Ca²⁺-ATPase activity is more suitable for quality assessment of prawn. The Ca²⁺-ATPase activity of protein decreased more slowly as the temperature lowered, and the performance differences of Ca²⁺-ATPase can be distinguished easily during storage at -10 ℃ to -40 ℃. Sulfhydryl content changed a little when the storage temperature varied from -10 ℃ to -40 ℃. Prawn protein is more stable than most freshwater fish. The salt solubility, Ca²⁺-ATPase activity and sulfhydryl content of prawn protein all decreased more slowly than usual freshwater fish. The protein of prawn denaturated mildly during frozen storage. -20 ℃ is economical and reasonable as a frozen storage and it can be selected as the practical frozen temperature.

Abstract:This investigation studied the effects of temperature, pH and substrate concentration on the autolysis processing of Litopenaeus vannamei head and the change law of the hydrolysate during the autolysis, a kinetic model of the autolysis reaction process was then established. Our purpose was to monitor autolysis course based on the kinetic model, by which we can not only obtain the anticipative molecular weight autolysate, but also increase protein recovery economically and effectively. The study was conducted to investigate the effects of temperature, pH and substrate concentration on the autolysis process of Litopenaeus vannamei head and the change law of the hydrolysate during the autolysis. The rules of the hydrolysate releasing during the first five hours fitted the first order reaction kinetics: Y= 39.496^e-0.3913x, KP = -1.146 4Y+59.506, Pe = -0.716 7Y+32.551. It showed a good linear relativity between KP, autolysis hydrolysate under 5 000 u and residual protein. In the course of autolysis, the important factors were temperature, pH and substrate concentration which affect shrimp head autolysis rate. During the autolysis, the value of Ka increased with temperature rising from 40 ℃ to 50 ℃ and reached a peak at 50 ℃, while the value of Ka reduced with temperature rising from 50 ℃ to 60 ℃; the effect of pH and substrate concentration on Ka did not show regularity, the value of Ka reaches a peak at pH9 and substrate concentration 1∶3, respectively. We established an Arrhenius equation LnKa = -13 654/T_k + 41.353 and used it to certify the efficacy of the kinetic model. At the beginning of the autolysis（0-1 h）, the hydrolysate above 5 000 u took a greater proportion, the percentage was 58%; the percentage of the hydrolysate under 5 000 u increases rapidly during 2-3 h, and was up to 66.8% at 3 h, the increase trend slowed down at 4-5 h, the percentage was 71.47%. In the course of autolysis (0 h-5 h), the release quantity of most of fatty amino acids increased 2-8 times, the content of aspartic acid is 0.13 mg/100mL after autolysis 5 h while its content was 0.017 mg/100 mL before autolysis; the increase content of glutamic acid followed aspartic acid, the content was 0.17 mg/100 mL after autolysis 5 h and the content was 0.041 mg/100 mL before autolysis; while the contents of heterocyclic amino acids-praline, histidine and the amino acids contain the group of sulphur like cysteine, methionine were stable, the contents of cysteine and proline kept at 0.006-0.009 g/100 mL and 0.07-0.09 g/100 mL, respectively. This paper intended to establish a kinetic model to fit the autolysis of Litopenaeus vannamei head.