• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.250-256
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• 2009

A 8-week feeding trial was conducted to investigate the effects of dietary supplementation of Kugija (Lycium chinense) on the growth and immunological response in juvenile Korean rockfish (Sebastes schlegeli). Six experimental diets were supplemented with Kugija at 0, 0.1, 0.5 1.0, 3.0 and 5.0% ($K_0,\;K_{0.1},\;Ko_{0.5},\;K_{1.0},\;K_{3.0},\;K_{5.0}$) on a dry-matter basis. After 2 weeks, triplicate groups of 30 fish initially averaging 3.36$\pm$0.2 g (mean$\pm$SD) were randomly distributed into the aquarium and were fed one of the experimental diets for 8 weeks. By the end of the 8-week feeding trial, fish fed the $K_{0.5}$ and $K_{1.0}$ diets exhibited a higher weight gain and specific growth rate than fish fed $K_0$ and $K_{0.1}$ diets (P<0.05). Feed efficiency of fish fed the $K_{0.5}$ diet showed significant higher value than that of fish fed the $K_0$, $K_{3.0}$ and $K_{5.0}$ diets (P<0.05). Hepatosomatic index of fish fed the $K_{0.5}$ diet was significantly higher than that of fish fed the $K_{0.1}$ and $K_{5.0}$ diets (P<0.05). Hematocrit of fish fed the $K_{0.5},\;K_{1.0}$ and $K_{5.0}$ diets was significantly higher than that of fish fed the $K_0$ diet (P<0.05). Glutamic oxaloacetic transaminase of fish fed the $K_{0.5},\;K_{1.0},\;K_{3.0}$ and $K_{5.0}$ diets was significantly lower than in fish fed the other diets (P<0.05). Glutamic pyruvic transaminase activity of fish fed the $K_{3.0}$ diet was significantly lower than those of fish fed the $K_0$ and $K_{0.1}$ diets (P<0.05). However, there was no significant difference in the activity of the transaminase in fish fed the $K_{0.5}\;K_{1.0},\;K_{3.0}$ and $K_{5.0}$ diets. Lysozyme activity of fish fed the $K_{0.5}$ and $K_{1.0}$ diets was significantly higher than that in fish fed the $K_0$ and $K_{0.1}$ diets (P<0.05). Respiratory burst activity of fish fed the $K_{3.0}$ diet was significantly higher than those of fish fed the $K_0$ and $K_{0.1}$ diets (P<0.05). However, there was no significant difference in respiratory burst activity of fish fed the $K_{0.5}\;K_{1.0},\;K_{3.0}$ and $K_{5.0}$ diets. Fish fed Kugija showed lower early mortality than fish fed a Kugija-free diet upon challenge with Vibrio ordalii. The results suggest that feeding of Kugija (Lycium chinense) enhances growth, non-specific immunity and disease resistance in juvenile Korean rockfish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.2
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• pp.113-126
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• 1988

Paralytic shellfish poison(PSP) accmulate in shellfish as a result of feeding toxic dinoflagellates. The shellfish do not seem to be harmed by the toxins, but become toxic to humans and other animals that feed on them. The purpose of this study was to investigate the distribution and changes of PSP by species of shellfish, collected area and collected month. Also, the correlation between PSP and toxic dinoflagellate, Protogonyaulax tamarensis, was investigated. Five hundred and six samples of 13 kinds of shellfish for PSP bioassay were collected at the shellfish growing area of Pusan, Masan, Chungmu, $Samch\check{o}npo, Y\check{o}su, Mokpo and Daech\check{o}n$ located in South Korea during the study period from May, 1985 to Octcber, 1987. Most of the samples submitted were free from PSP except sea mussel, short - necked clam and ark shell. Among the intoxicated samples, PSP was most often detected in sea mussel. PSP was detected mainly in spring$(February\~May)$ in the southern coast of Korea. In case of Pusan, exceptionally, toxic sea mussel have been found even June and July in 1987. The toxicity score of toxic shellfishes examined was ranged from 23.44 to $150.26{\mu}g/100g$ of edible meat and toxicity of sea mussel was higher than other toxic shellfishes. By the study of anatomical distribution of PSP in sea mussel collected at Masan in Febuary and March, 1986, the toxin accumulated in digestive gland was about $70\%$ of all. There was no significant correlation between toxicity of sea mussel and cell numbers of P. tamarensis that one of the causitive organism of PSP during the studying period in Masan area. There was almost no difference in toxicity of sea mussel by water depth of collection, but toxicity of surface shellfish was a little higher than those of 3.5, and 7.0m depth.