Suppression of fish meat softening by strict control of storage temperature     

Masashi Ando  Shintaro Mizuochi  Yasuyuki Tsukamasa  Ken -Ichi Kawasaki 《Fisheries Science》2007,73(3):705-712

ABSTRACT:   Changes in meat firmness and structure of cultured yellowtail at several storage temperatures, from −1.5°C to 10°C, were compared. Firmness decreased less at −1.5°C and 10°C than at the other temperatures. During storage at temperatures from −0.5 to 4.0°C, expansion of intercellular space, which indicates weakening of the connecting force between muscle cells, began to increase after 8 h storage, and the ratio of space to the whole area increased by 3.4–4.9 times after 24 h of storage. However, at −1.5°C and 10°C, the increase of intercellular space was suppressed, and the ratio was 2.4–2.6 times, even after 24 h storage. Collagen fibrils connecting muscle cells disintegrated after 24 h storage at all storage temperatures. Conversely, in 10°C storage, the fine structure of muscle, except for collagen fibrils, was maintained better than at other storage temperatures. These findings indicate that −1.5 and 10°C storage could maintain fish-meat quality for longer periods than storage at −0.5, 1.0, or 4.0°C, the normal refrigeration temperature.  相似文献   

Effects of Using Live Grass Shrimp (Palaemonetes varians) as the only Source of Food for the Culture of Cuttlefish, Sepia officinalis (Linnaeus, 1758)   总被引：1，自引：0，他引：1  

António V. Sykes  Pedro M. Domingues  José P. Andrade 《Aquaculture International》2006,14(6):551-568

The life cycle of cuttlefish fed ad libitum exclusively on live grass shrimp (Palaemonetes varians) was studied during 5 consecutive generations. Different culture temperatures promoted different (P < 0.05) exponential growth for each life cycle, being summer generations shorter than those of winter. Higher temperatures promoted higher IGR’s and mortality, while lower temperatures promoted increased life span, reproduction stages, total fecundity and total egg biomass. Increased generations also seemed to increase fertility. A “hybrid” generation promoted the best results in terms of hatchling weight, individual fecundity and fertility. Mean egg weight was related to female size and embryonic development took longer at lower temperatures. Brood stock sex ratios seemed to be temperature related. All of these culture aspects were also compared between themselves in order to establish future brood stock methodologies. Grass shrimp proved to be a good diet for the culture of cuttlefish throughout the life cycle. The use of only one species reduces costs and labor associated to cuttlefish culture.  相似文献   

Effects of melatonin implants on reproduction and growth of turbot broodstock     

J.M.R. Alvariño  P.G. Rebollar  M. Olmedo  B. Alvarez-Blázquez  E. Ubilla  J.B. Peleteiro 《Aquaculture International》2001,9(6):477-487

The effect of 18 mg. melatonin (MLT) implants on thereproductive performance of turbot (Scophthalmus maximusL.) broodstock was determined in 20 females and 12 males. Implantedanimals showed supra-physiological plasma MLT concentrations during threemonthsafter implantation, being at that time about one hundred times higher thandiurnal MLT concentrations. Direct effects of MLT implants were observed ongonadal maturation of turbot females three months after implantation (P <0.01), although the faster ovarian response to increasing photoperiod was notconsistent and no differences were detected at the final reproductiveperformance. MLT implants had a positive effect on turbot male reproductivefeatures, since gonadal recrudescence started 45 days earlier (P < 0.05)showing a trend towards higher spermatozoa concentration. Further research isadvisable to ascertain the MLT dose required for and time of implantation inturbot broodstock.  相似文献   

Analysis of exotoxins produced by atypical isolates of Aeromonas salmonicida,by enzymatic and serological methods     

Gudmundsdóttir BK  Hvanndal I  Björnsdóttir B  Wagner U 《Journal of fish diseases》2003,26(1):15-29

In this study, exotoxins produced by 62 Aeromonas salmonicida strains and the bacterium Haemophilus piscium were analysed. Enzymatic assays, zymograms and serological detection were used to monitor secretion by bacterial strains of the previously described exotoxins P1, GCAT and AsaP1 and also the extracellular P2 metallo-gelatinase and a serine caseinase, which is different from the P1 protease and has not yet been characterized. Based on the results, the strains were divided into five groups. One comprised the type strains for A. salmonicida ssp. masoucida, H. piscium and 36% of the atypical isolates, and another, a type strain for A. salmonicida ssp. smithia together with 14% of the atypical isolates. A second type strain of A. salmonicida ssp. smithia was grouped with 8% of the atypical isolates. The largest group contained the type strains for A. salmonicida ssp. achromogenes and 38% of the atypical isolates. The type strains for A. salmonicida ssp. salmonicida were in the last group with all the four typical strains and 4% of the atypical isolates. The combination of zymogram and serological detection used is recommended as the most reliable method for characterizing A. salmonicida strains according to their exotoxin secretion.  相似文献   

Effects of paraquat treatment on fish transaminase molecular subforms     

K. Aranka Deér  János Nemcsók  LászIó Boross  Béla Szajáni 《Fish physiology and biochemistry》1990,8(1):79-83

The effects of paraquat (PQ; 1,1′-dimethyl-4,4′-bipyridylium dichloride) treatment were investigated in carp, silver carp and wels. The serum glutamic-oxalacetic transaminase (GOT; L-aspartate: 2-oxoglutarate aminotransferase, EC 2.6.1.1.) level was enhanced by 50% at 1 ppm exposure and by 100% at 10 ppm exposure in all species, and there was a change in the distribution of the molecular subforms of GOT in the liver and heart. The activities of the individual subforms decreased with increasing PQ concentration or after a longer exposure. In some cases, one of the subforms was no longer present in the liver. An increased serum GOT activity, a decreased enzyme activity in different organs and the disappearance of molecular subform indicate tissue damage.  相似文献   

Maturity and reproduction of goneplacid crab <Emphasis Type="Italic">Carcinoplax vestita</Emphasis> (Decapoda,Brachyura) in Tokyo Bay     

Wataru Doi  Than Than Lwin  Masashi Yokota  Carlos Augusto Strüssmann  Seiichi Watanabe 《Fisheries Science》2007,73(2):331-340

ABSTRACT:     Sexual maturity, morphological sexual dimorphism, and reproduction of the goneplacid crab Carcinoplax vestita were investigated in Tokyo Bay, Japan, from November 2002 to October 2003. The puberty molt in males was evidenced by changes in the relative size of the chelipeds and merus of the walking legs, and was estimated to occur at a size range of 13.20–18.85 mm carapace length. Post-pubertal females were identified by the relative size of the abdomen and puberty was estimated to occur at a size range of 12.81–15.46 mm carapace length. Sexual dimorphism in C. vestita was observed in all features that showed secondary sexual characteristics. Monthly changes of gonad index in males, and of seminal receptacle index and occurrence of sperm plugs in females were synchronized, and indicated that mating was intense in spring. Ovaries began developing in March. Ovigerous females were found in all months except December, but were clearly more abundant between August and October. Fecundity ranged from 7800 to 57 000 mature oocytes per female per batch and was highly correlated with body size. The results suggest that some females may spawn more than one batch per year.  相似文献   

Carbon source and trophic position of pelagic fish in coastal waters of south-eastern Izu Peninsula,Japan, identified by stable isotope analysis     

Noriyuki Takai  Noriyuki Hirose  Takuya Osawa  Kazuyuki Hagiwara  Takahito Kojima  Yuji Okazaki  Tomohiro Kuwae  Toru Taniuchi  Kiyoshi Yoshihara 《Fisheries Science》2007,73(3):593-608

ABSTRACT:   It is important to clarify trophic dynamics in marine ecosystems for management of the fishing ground. Organic carbon sources and trophic position of pelagic fishes in the coastal waters of the south-eastern Izu Peninsula, Japan, were examined on the basis of carbon and nitrogen stable isotope distributions. The δ¹³C of the fishes was mostly distributed from −19 to −16‰ for nektonic fishes (13 species of adults and immatures) and planktonic fishes (10 species of larvae and juveniles), close to the δ¹³C values of particulate organic matter and planktonic decapods. These δ¹³C signatures for the inhabitants of the water column were in contrast with the high δ¹³C values (mainly −16 to −13‰) for demersal fishes of Scorpaeniformes and benthic polychaetes collected in the surf zone. These results indicate that nektonic and planktonic fishes depend on phytoplankton for carbon supply. The δ¹⁵N signatures suggest that the trophic position ranged 3.1–4.5 for the nektonic fishes and 2.9–3.7 for the planktonic fishes, premised on trophic level 3 for larval Japanese anchovy Engraulis japonicus . Thus, planktivorous fishes should be mainly assigned to trophic levels 3 and 4 in this area.  相似文献   

Growth changes in bighand thornyhead <Emphasis Type="Italic">Sebastolobus macrochir</Emphasis> off the Pacific coast of northern Honshu,Japan     

Tsutomu Hattori  Yoji Narimatsu  Masaki Ito  Yuji Ueda  Kunihiro Fujiwara  Daiji Kitagawa 《Fisheries Science》2007,73(2):341-347

ABSTRACT:     The biomass of bighand thornyhead Sebastolobus macrochir was increased by the high recruitment success of the 1999–2002 year classes off the Pacific coast of northern Honshu, Japan. In this study, the growth of bighand thornyhead was examined over a 9-year period from 1996 to 2004 in this area. The growth of the 1999 year class and the 2000–2002 year classes was reduced at 3 and 2 years old, respectively, while the 1999–2002 year classes were smaller than the 1993–1998 year classes. In 2-, 3- and 4-year-old fish, the relationship between abundance and mean standard length was expressed by negative linear regressions, while fish became smaller when abundance of the year class was larger. Mean bottom temperatures were stable at depths of 350–900 m; variations in water temperature were small in the main distribution area of bighand thornyhead. We discuss the factors affecting the growth of bighand thornyhead via changes in the demersal fish community and feeding habits.  相似文献   

Elemental analysis of otoliths of Japanese anchovy: trial to discriminate between Seto Inland Sea and Pacific stock     

Hiromu Zenitani  Ryo Kimura 《Fisheries Science》2007,73(1):1-8

The ability to discriminate local stocks of Japanese anchovy Engraulis japonicus was assessed based on data from four elements (K, Na, P, and Sr) using an electron probe micro analyzer (EPMA) and data from three elements (Ba, Mn, and Sr) using inductively coupled plasma mass spectrometry (ICP-MS) from the otoliths of 40 anchovy (23.6–47.0 mm body length). Anchovy were caught at three sites (Aki-nada, Hiuchi-nada, and Osaka Bay) in the Seto Inland Sea, and one site (Kuroshio extension) in the Pacific Ocean in 2002. In order to discriminate different spawning grounds, EPMA data from the core portion (from core to 30 μm in the core-posterior axis) were used. Results showed that it was difficult to discriminate between the Seto Inland Sea and the Pacific anchovy by EPMA data. Conversely, it was possible to discriminate between the Seto Inland Sea and the Pacific anchovy by ICP-MS data from bulk otoliths. Our results showed that Mn contents of otoliths using ICP-MS discriminate between spawning grounds most, and Ba and Sr discriminate less. The difference in elemental compositions in anchovy otoliths between the Seto Inland Sea and the Pacific Ocean might be reflected by cumulative experienced elemental composition of ambient sea water during life history between the Seto Inland Sea and the Pacific anchovy.  相似文献   

Cloning of a gonadal follicle stimulating hormone receptor cDNA from the European sea bass, Dicentrarchus labrax     

A. Rocha  A. Gómez  M. Carrillo 《Fish physiology and biochemistry》2003,28(1-4):359-360

The molecular cloning of the sea bass FSH receptor gene is reported. Expression analysis revealed that this gene is exclusively expressed in gonadal tissues.  相似文献