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Volume 38, Issue 4
Displaying 1-18 of 18 articles from this issue
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Masaru AMIO, Tatsuo HAMANO1990 Volume 38 Issue 4 Pages 315-318
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSCrystalline style (CS) volume is an indispensable parameter to estimate a density of Cristispira spirochetes whose density indicates the vitality of bivalves. In the present study, the CS volume of three bivalves, Ruditapes philippinarum, Corbicula leana, and C.japonica, were calculated from the CS length by regression equations as follows. The outline of CSs of fresh individuals were traced with the aid of a camera lucida. CSs traced were classified into two types by shapes, i. e. a cone and two truncated cones (I) or two truncated cones (II), to measure the CS length and the CS volume. As a result, three formulae were calculated: V=0.02818L2.229, V=0.005733L2.739, and V=0.03644L1.931 for R. philippinarum, C. leana, and C. japonica, respectively, where V is volume (mm3) of a CS when the length is L (mm) . Type II included soft CSs in dissolution.View full abstractDownload PDF (318K) -
Yasuhisa KAYANO, Dal-Sang JEONG, Tadashi ODA, Heisuke NAKAGAWA1990 Volume 38 Issue 4 Pages 319-326
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn order to obtain optimum feeding condition in young red spotted grouper Epine-phelus akaara, feeding trial was carried out in terms of growth and body constituents. Totally 16, 000 young fish of 3.41cm in average total length were devided into five floating net cages. Five groups with different feeding frequencies were designated as follows: one feeding in 2 days (group I), 1 day (group II), two feeding daily (group III), four feeding daily (group IV) and eight feeding daily (group V) . Each group was satiated with one feeding, and fed with composed diet for 40 days. Total feed intake was increased with enhancing feeding frequency.
The highest weight gain and good feed conversion efficiency as well as higher survival were obtained in group IV. Body constituents were closely related to the amount of feed given. Muscle protein and lipid were increased in response to feeding frequency. More than 50% of triglycerides of the fish were accumulated in the intraperitoneal fat body. Triglyceride accumulation in whole body reached maximum at four feeding daily.
According to the above results, the optimum feeding frequency might therefore be two or four feeding daily.View full abstractDownload PDF (782K) -
Hideo YAMANOI, Tadashi ODA, Kazuo UKIDA1990 Volume 38 Issue 4 Pages 327-332
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effects of sodium nifurstyrenate (NS) bath and freezing of rotifers (Brachionus plicatilis) and brine shrimp (Artemia salina) on the survival rate and the aerobic bacterial intestinal flora of ayu larvae were investigated at the Fish Farming Center. In the fish groups I, II, and III, NS-treated, frozen, and non-treated live diets were given, respectively, prior to or together with artificial diets. Bacterial count (ZoBell's 2216e agar) of ayu larvae of the group I was 1.4×10 CFU/fish at 10-day old. It increased to 1.2×103 CF U/fish at 20-day-old, and continued on that level untill 64-day-old. At 77-day-old, when the fish were given only artificial diet, bacterial count reached to 5.1×104 CFU/fish. In the group II, it fluctuated between 102 and 104 CFU/fish. Bacterial counts of the fish group III (control) increased to 2.5×105 CFU/fish at 77-day-old. Average of bacterial counts through the experimental period (80 days) in the group I, II, and III, were 1.1×104, 4.8×103, and 5.0×104 CFU/fish, respectively. Vibrio (55.2-67.9%) constituted dominant bacteria in all the groups, the differences among groups being small at average. Totally, expected good results in rearing of ayu larvae by treating live diets were not obtained in the hatchery. Survival rates in the three groups at the end of the experiment were 77.7, 24.6, and 96.9%, respectively.View full abstractDownload PDF (673K) -
Houji IWATANI1990 Volume 38 Issue 4 Pages 333-336
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
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Yoshimasa AKIMOTO, Kaoru SUZUKI, Katsuhiko ENDO1990 Volume 38 Issue 4 Pages 337-342
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
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Cyril Glenn SATUITO, Kazutsugu HIRAYAMA1990 Volume 38 Issue 4 Pages 343-347
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSeveral reports have already shown that baker's yeast is a nutritionally insufficient food for mass production of the rotifer, Brachionus plicatilis, but its inadequacy can be improved by the supplementation of nutrients in the rotifer culture water. In such studies, it is often neglected that yeast tends to settle at the bottom of containers, becoming unavailable to the rotifer during static cultures. This study then focused to the finding of a culture method that will resuspend the yeast cells without hindering the reproduction of the rotifer during cultures. The effect of shaking (vertical and horizontal) or stirring on the reproduction of the rotifer was investigated by culturing rotifers in several yeast suspensions supplemented with Nannochloropsis oculata at different densities. The reproductions were compared between shaked and their static cultured counterparts.
Vertical shaking (300 times/min, for 15 minutes) of the rotifer was found to hinder reproduction even at a shaking frequency of only once a day. Stirring the culture water with a magnet stirrer caused physical damage on the inoculated eggs, resulting in a hindered reproduction of the culture. Horizontal shaking of rotifer cultures at a speed of 130 times/min. for 15 minutes 6 times a day showed to be effective in resuspending yeast cells, resulting in growths higher than their static cultured counterparts.View full abstractDownload PDF (585K) -
Daisuke FUJITA1990 Volume 38 Issue 4 Pages 349-352
Published: December 31, 1990
Released on J-STAGE: December 10, 2010
JOURNAL FREE ACCESSTetraspores of Lithophyllum yessoense Foslie, a dominant subtidal crustose coralline alga in ‘Isoyake’ (urchin-dominated barren) ground of Southwestern Hokkaido, were cultured in the modified Grund medium at 15°C, 12 : 12 LD with 20W/m2 After early developement following the pattern of the Amphiroa-type, germlings became two-layered at ca. 70 celled-stage, and differentiated into germlings of ca. 500μm in diameter with three cell layers, namely epithallium, perithallium and hypothallium. The morphology of the epithallal cells was of the ‘horizontal growth-type’ in the early stages. After one year, germlings grew into discoid crusts of 16.9±6.0mm2, with 190±60μm thickness. Cross section of one-year-old crust revealed that the number of cell layers of epithallium and perithallium had increased to 2-3 and 14-15, respectively. At this stage, crust surface except margin showed ‘vertical growth-type’, where epithallial shedding was observed. Crust part with ‘horizontal growth-type’ epithallial cells are thought to function as a coverage for the substratum, and the remainder with ‘vertical growth-type’ for anti-fouling and anti-grazing.View full abstractDownload PDF (4658K) -
Heisuke NAKAGAWA, Tadao KUSUNOKI1990 Volume 38 Issue 4 Pages 353-359
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSOreochromis niloticus with 18.3g of average body weight were reared with three different diets for 91 days. Group 1 was solely fed with a commercial diet. Diets of group 2 and 3 were supplemented with medium chain triglycerides (MCT) which were consistedof C6 (1.6%), C8 (58.1%), C10 (39.6%), and C12 (0.7%), and pollack liver oil (PLO), respectively.
MCT did not affect growth or feed efficiency. PLO increased significantly lipid deposition in muscle, liver, and intraperitoneal fat body. Nevertheless, dietary MCT suppressed lipid accumulation in these organs. Analysis of fatty acid composition reflectedthat MCT were effectively consumed as energy source without deposition in body, whilethe excessively fed long chain triglycerides were accumulated in the body.
MCT would be available as feed supplementation for improvement of fish quality.View full abstractDownload PDF (598K) -
Akio HIRAI, Shigenobu OKUMURA1990 Volume 38 Issue 4 Pages 361-365
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe fine structure of the egg membrane and micropyles in unfertilized and fertilized eggs of the Japanese blanquillos, Branchiostegus japonicus were examined and compared with other species using a scanning electron microscope. Fine pores, in 50/100μm2approximately, are uniformly distributed on the surfaces of the egg membrane. The micropylar canal of unfertilized egg opens outward like a funnel and passes through egg membrane to interior surface. While, the micropylar canal of fertilized egg is closed completely and the structure of a cone appears in the center of its entrance. The observation of the micropylar canal may be available to examine whether egg has been fertilized or not, and the micropylar structure of fertilized egg of this species may be used for the identification of eggs from the sea.View full abstractDownload PDF (5340K) -
Toshiaki YADA1990 Volume 38 Issue 4 Pages 367-373
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
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Toshiaki YADA, Jiro SIBATA, Yoshihito AZUMA1990 Volume 38 Issue 4 Pages 375-381
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESS -
1990 Volume 38 Issue 4 Pages 382-388
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
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Masaru TANAKA1990 Volume 38 Issue 4 Pages 390-391
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
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Tatuhiro FUKUNAGA1990 Volume 38 Issue 4 Pages 391-394
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
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Tadahisa SEIKAI1990 Volume 38 Issue 4 Pages 394-395
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDownload PDF (259K) -
Kazuo TABATA1990 Volume 38 Issue 4 Pages 395-396
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
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Kiyokuni MUROGA, Toshihiro NAKAI1990 Volume 38 Issue 4 Pages 396-397
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
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Akio KANAZAWA1990 Volume 38 Issue 4 Pages 398-399
Published: December 31, 1990
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDownload PDF (263K)
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