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Volume 30, Issue 4
Displaying 1-9 of 9 articles from this issue
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[in Japanese], [in Japanese]1983 Volume 30 Issue 4 Pages 179-183
Published: March 25, 1983
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESS -
[in Japanese], [in Japanese]1983 Volume 30 Issue 4 Pages 184-191
Published: March 25, 1983
Released on J-STAGE: September 07, 2010
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H. NAKAGAWA, S. KASAHARA, E. UNO, T. MINAMI, K. AKIRA1983 Volume 30 Issue 4 Pages 192-201
Published: March 25, 1983
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe determination of physiological merit of supplemental Chlorella-extract in ayu, Plecoglossus altivelis, was followed by the previous results that it endowed resistant power against disease.
Ayu of body weight 46 g was fed on the composed feed with 4% of feed oil (control group) . Experimental groups, A and B were respectively fed 1 % and 2% of the Chlorella-extract to the above feed. The Chlorella-extract was prepared from Chlorella vulgaris E-25 with hot water for 1 hr, and 60% of sucrose were added as an antiseptic. After 42 days feeding blood properties and body composition were analysed.
1) The extract-fed groups showed low fatness and gonadosomatic index, and high hepatosomatic index. The effect of retardation of sexual maturation was suggested by the Chlorella-extract feeding.
2) The extract effectively deprerssed the lipid contents of the serum, dorsal muscle, and viscera.
3) In order to compare the response to acute handling stress, fish were exposed to air (air-dipping) for 2 min before being returned to O2-saturated water. Time course of recovery was serologically monitored for a period of 20 min post-air-dipping. The extract-fed groups trended to be tolerant to the air-dipping, comparing with control group.
4) The physiological effect of the Chlorella-extract was most probably associated with lipid metabolism.View full abstractDownload PDF (1201K) -
Y. TSUKASHIMA, N. YOSHIDA, C. KITAJIMA, S. MATSUMURA, C.L. BESCH III1983 Volume 30 Issue 4 Pages 202-210
Published: March 25, 1983
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe Japanese whiting Sillago Japonica (T.et S.) is a valuable coastal resource, however, for mass-rearing of this fish the rotifer, Brachionus plicatilis used generally is too large for the inital feeding of this particularly small larvae and some trials using oyster larvae have been conducted with only limited success because of difficulties in supplying the necessary amount.
In this paper the use of rotifer of relatively smaller size, separated from the cultured population by filtration through a 71μ mesh net, was examined.
Fertilized eggs were collected from adults spawning naturally in a 6 ton concrete tank. In the preliminary trial, survival and growth of the larvae resulting from 3 different feeding programs (A: small rotifer at a density of 20 ind./ml, B: unfiltered rotifer at a density 20 ind./ml, C: unfiltered rotifer at a density of 100 ind./ml) in three 1 ton clear plastic tanks were compared with each other. The results were good for tank A with an 83% survival rate after 8 days, while tank B and C showed only 18.7% and 2.4%, respectively. The growth rate also showed the same trend (A>B>C) .
The mass-rearing experiment was conducted based on the results of the preliminary trial with 300, 000 eggs stocked in a 10 ton concrete tank. From the 2nd to 5th day after hatching, filtered rotifer at a density of about 20 ind./ml were given. Seven days old larvae were given unfiltered rotifer collected in a 37μ mesh net for 9 days, then rotifer collected in a 100μ mesh net were introduced until day 29. Afterward live ade frozen Tigriopus japonicus, Artemia enriched with the essential fatty acids by adding emulsionized “Ester 85” to its culture medium, and finally minced sand eel were offered.
The approximate survival rate and total length after about 40 days were 50% (150, 000 ind.) and 30 mm, respectively. Three and a half months old fish reached an average length of 7.2 ± 0.85cm and a weight of 2.9 ± 1.15g.View full abstractDownload PDF (861K) -
[in Japanese], [in Japanese], [in Japanese]1983 Volume 30 Issue 4 Pages 211-218
Published: March 25, 1983
Released on J-STAGE: September 07, 2010
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[in Japanese]1983 Volume 30 Issue 4 Pages 219-221
Published: March 25, 1983
Released on J-STAGE: September 07, 2010
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[in Japanese], [in Japanese]1983 Volume 30 Issue 4 Pages 222-225
Published: March 25, 1983
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESS -
[in Japanese]1983 Volume 30 Issue 4 Pages 226-227
Published: March 25, 1983
Released on J-STAGE: September 07, 2010
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[in Japanese], [in Japanese]1983 Volume 30 Issue 4 Pages 228-232
Published: March 25, 1983
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESS
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