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Volume 34, Issue 2
Displaying 1-13 of 13 articles from this issue
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Kunihiko FUKUSHO, Takuya FUJIMURA, Takeshi YAMAMOTO1986 Volume 34 Issue 2 Pages 69-75
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe red seabream, Pagrus major is one of the most important marine fishes being cultured in Japan. Natural spawning is commonly used for spawn taking in mass fry production, and advanced spawning has been achieved by manipulation of water temperature. Control of spawning is important not only for obtaining early seedling, but also for hybridization and gynogenesis experiments in which sperm of various species having different spawning season are used. But, there is lacking in basic and precise informations for control, especially water temperature conditions and design of broodstock tank.
An indoor broodstock tank (30m3) equipped with a sand filter and a circulatory apparatus, was originally designed and constructed in the National Res. Inst. Aquaculture. Facilitation of early spawning was attempted by manipulation of water temperature in the broodstock tank. Forty eight hatchery reared fish (two-years old, 36cm in average T.L. and 700g in B.W.) were introduced into the tank on May 21, 1984 and raised for nearly 7 months on commercial pellets. Water temperature was not controlled during this period. On January 7, 1985, when water temperature in the broodstock tank dropped to 14°C, it was raised and maintained at 16°C until April 30, 1985.During this period krill was daily supplied to the fish in addition to the pallets.
Spawning was observed on May 28, 1985 and continued until June 21 (for 86 days) .Thus, the spawning was advanced 20 days by the temperature manipulation. One of the treated female produced 1.95 million eggs (ca.1, 086g=1.58 times of body weight) during the spawning season. The initial plan for advancing the spawning by two months was yet acheived, while the results might be highly evaluated as a ordinary broodstock in the tank instead of net cage. The relationship between various water temperature and facilitation of the spawning season should be investigated in detail.View full abstractDownload PDF (1962K) -
Yoshihito ITO, Tadashi KAMATA, Yoshito TANAKA, Muneo SAMESHIMA1986 Volume 34 Issue 2 Pages 77-80
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effect on pigmentation of the skin of red sea bream Pagrus majorby astanthin and astaxanthin dipalmitate was investigated. Fish (ca. 270g) were fed the diet containing astaxanthin and astaxanthin dipalmtate (100 ppm as astaxanthin) for 1 or 2 months. The separation of carotenoids was performed on silica gel (Silica gel 60, Merck) column chromatography.
The results obtained from this experiment were as follows:
1) The improvement of the body color of red sea bream by supplemented astaxanthin was observed. In the group of astaxanthin, the astaxanthin content in the skin of red sea bream after 1 month increased, but after 2 months additional increase of astaxanthin could not be found.
2) In the group of astaxanthin dipalmitate, the value of astaxanthin content in the skin of red sea bream after 1 or 2 months was higher than that in the group of astaxanthin. On the deposition of astaxanthin in the skin of red sea bream, astaxanthin dipalmitate was more effective than astaxanthin.View full abstractDownload PDF (383K) -
Yoshie DOTSU1986 Volume 34 Issue 2 Pages 81-82
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe eggs of tiger puffer are provided with an adhesive milky opaque external chorion, making it difficult to observe the embryonic development of the eggs under microscope.
The external chorion could be removed in sea water contained 2-4% volume of commercial hypochlorite, which contained a little over 5% active ingredient, in 10-15 minutes at about 16°C of water temperature. After the external chorion was removed, a transparent inner chorion appeared, through which the embryonic development was clearly observed.View full abstractDownload PDF (170K) -
Diagnostic Studies on Nutritional Disease Caused by Various DietsHeisuke NAKAGAWA, Kenji NANBA, Hidemi KUMAI, Motoji NAKAMURA, Shogoro ...1986 Volume 34 Issue 2 Pages 83-90
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn order to establish compound diet of fugu (Takifugu rubripes), the fish were reared on various diets for 60 days. Sand lance (Ammodytes personatus), mackerel (Pneumatophorus japonicus japonicus), krill (Euphausia sp.), sardine (Sardinops melanostictus), and pelletted commercial diet for red sea bream were solely fed and were assessed as diet according to growth, blood parameter, and histological observation.
The fish fed on sand lance exhibited the highest growth. The mackerel, krill, and sardine were available in this order, and these dietary groups as well as the sand lance fed group showed no symptom of physical morbidity according to blood parameters.
The commercial diet feeding exhibited low in growth, condition factor, and hepatosomatic index. The hematological measurements of the group were not different from each other, but the serological measurements such as total lipid, glucose, and nonesterified fatty acids were significantly low and different from the other groups. At the end of the experiment, parasitic disease “white spot disease” of all dietary groups caused severe decrease in body weight and high mortality.
The muscle and viscera were histologically observed. Most liver cells of all dietary groups were distended by large globules of fat. The size and shape of the globules were variable in response to the diets. Skeletal muscle often showed liquefactive necrosis in sardine feeding and especially assorted commercial diet feeding.
The low growth rate and some morbidities in commercial diet fed group were likely caused by nutritional defficiency resulted from malcondition of absorption or digestion.View full abstractDownload PDF (4437K) -
Ken-ichi YAMAMOTO, Hiroshi KOBAYASHI1986 Volume 34 Issue 2 Pages 91-94
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
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Toshio IWAI, Hiroyoshi OSAMA1986 Volume 34 Issue 2 Pages 95-102
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
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Toshio IWAI, Takayuki TSUGE1986 Volume 34 Issue 2 Pages 103-106
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
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Motility and Fertilizing Capacity of Sperm after Chilled StorageMasayoshi UNO, Nakao INOKAWA, Hisashi KUROKURA1986 Volume 34 Issue 2 Pages 107-111
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
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Fertilizing Capacity of Sperm after CryopreservationMasayoshi UNO, Fumiaki MINESHIMA, Hisashi KUROKURA1986 Volume 34 Issue 2 Pages 113-117
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
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Shigeto NAGAO, Kiyoshi SAKAI, Fumio TAKASHIMA1986 Volume 34 Issue 2 Pages 119-125
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSInfluences of testicular maturation and rearing conditions on the saprolegniasis in landlocked varity of O. masou (yamame in Japanese) were examined.
Saprolegnia infection was recognized at the time of full maturation especially in male which gave milt after spermiation. In that case, histolgical changes such as thinning of the epidermis and decreasing of mucus cells in number were recognized. Environmental conditions such as high density, starvation and forced swimming were not regarded as causative factors of the infection.View full abstractDownload PDF (3388K) -
Shigeto NAGAO, Fumio TAKASHIMA1986 Volume 34 Issue 2 Pages 127-129
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSOral administration of 11-ketotesterone and methyltestosterone evoked hyperplasia of epithelial cells and hypoplasia of mucous cells in the epidermis.17α, 20β-dihydroxyprogesterone and cortisol acetate elicited no significant changes.
From the results obtained it was postulated that Saprolegnia infection in fully matured male was seemed to correlate with structural changes in the skin evoked by theandrogens which played a role in spermiation.View full abstractDownload PDF (1840K) -
Masayoshi MURAKOSHI, Kiyoshi KAKAZU1986 Volume 34 Issue 2 Pages 131-136
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
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Shigehisa YAMASAKI, Hachiro HIRATA1986 Volume 34 Issue 2 Pages 137-140
Published: September 30, 1986
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSFood consumption rates of L-type (large size) and S-type (small size) rotifer Brachionus plicatilis were determined in weight. Six levels of marine alga Chlorella hirataii were prepared between the range of 0.5 and 15×106 cells/ml. These food densities were maintainded for six days by supplying concentrated algae intermittently with peristaltic pump. Rotifer density was adjusted at about 20 ind/ml for L-type rotifer, and 40 ind/ml for S-type rotifer. Temperature was controlled at 25±1.0°C, and the salinity was 20‰.
Food consumption retes in wieght per unit body weight of L-type and S-type rotifers were about the same values within each food density. The food consumption rates increased as food density became higher. However, above 5×106 cells/ml the rates showed to be constant at about 480% of body weight per day. Saturated consumption rate was estimated at 480%/day for both L-type and S-type rotifers.View full abstractDownload PDF (394K)
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