Now showing items 1-6 of 6

    • Article

      Development of a method for reproducing epizootic ulcerative syndrome using controlled doses of Aphanomyces invadans in species with different salinity requirements 

      ES Catap & BL Munday - Aquaculture, 2002 - Elsevier
      Lesions typical of epizootic ulcerative syndrome (EUS) were induced in three-spot gourami, Trichogaster trichopterus, and sand whiting, Sillago ciliata, injected intramuscularly with controlled doses of Aphanomyces invadans zoospores, the fungal pathogen associated with the disease. Both species of fish exhibited chronic granulomatous response and inflammatory cells, predominantly macrophages and lymphocytes, infiltrated the muscle and skin tissues, at days 6–8 post-inoculation of 65 to 85 spores/fish. Based on the comparative granuloma counts and percentage of cellular infiltration in a sampled lesion area using image analysis, it was shown that the three-spot gouramis mounted a more vigorous response than the sand whiting. It was also observed that lesions in three-spot gouramis exhibited early signs of resolution than those in sand whiting. However, fish mortality was greater in EUS-affected three-spot gourami than in EUS-affected sand whiting. With this technique, we were able to describe and compare the sequential histopathology of EUS lesions in a freshwater (three-spot gourami) and an estuarine (sand whiting) fish species.
    • Article

      Enhancement of innate immunity in rainbow trout (Oncorhynchus mykiss Walbaum) associated with dietary intake of carotenoids from natural products 

      EC Amar, V Kiron, S Satoh & T Watanabe - Fish and Shellfish Immunology, 2004 - Elsevier
      The effects of orally administered carotenoids from natural sources on the non-specific defense mechanisms of rainbow trout were evaluated in a nine-week feeding trial. Fish were fed four diets containing either β-carotene or astaxanthin at 100 and 200 mg kg−1 from the marine algae Dunaliella salina and red yeast Phaffia rhodozyma, respectively, and a control diet containing no supplemented carotenoids. Specific growth rate and feed:gain ratio were not affected by dietary carotenoid supplementation. Among the humoral factors, serum alternative complement activity increased significantly in all carotenoid supplemented groups when compared to the control. On the other hand, serum lysozyme activity increased in the Dunaliella> group but not in the Phaffia group, whereas plasma total immunoglobulin levels were not altered by the feeding treatments. As for the cellular responses, the superoxide anion production from the head kidney remained unchanged while the phagocytic rate and index in all supplemented groups were significantly higher than those of the control. These findings demonstrate that dietary carotenoids from both D. salina and P. rhodozyma can modulate some of the innate defense mechanisms in rainbow trout.
    • magazineArticle

      Glucans and disease resistance 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The paper presents the usefulness of beta-glucans as immunostimulants for strengthening the non-specific defense system of a wide range of animals. In Taiwan, researchers tested the effects of beta-glucans on the vibriosis resistance of tiger shrimp Penaeus monodon which yield promising results. They suggest that supplementation of beta-glucan at 0.5 mg per ml is sufficient in strengthening the non-specific defense mechanism of postlarval shrimp.
    • Book chapter

      Immunity and biological methods of disease prevention and control 

      JME Almendras - In GD Lio-Po, CR Lavilla & ER Cruz-Lacierda (Eds.), Health Management in Aquaculture, 2001 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The chapter deals with the barriers that prevent microbial entry and the various internal defense mechanisms that are part of the host's arsenal in combating in combating invading microbes. It also discusses some of the biological methods of disease prevention and control.
    • Article

      Influence of various dietary synthetic carotenoids on bio-defence mechanisms in rainbow trout, Oncorhynchus mykiss (Walbaum) 

      EC Amar, V Kiron, S Satoh & T Watanabe - Aquaculture Research, 2001 - Wiley-Blackwell
      This study examined the influence of different carotenoids on growth and some immune indices in rainbow trout. Six semipurified casein-based diets were formulated to contain one of three different carotenoids: astaxanthin, canthaxanthin and β-carotene, at 100 mg kg−1, each of them with vitamins A, C and E either added or omitted. The two control diets contained no carotenoids and were either with or without the vitamins. Rainbow trout weighing about 140 g were fed the diets for 9 weeks. Specific growth rate, feed:gain ratio and nonspecific immune parameters were determined. Growth and feed conversion were similar among the groups. Immune parameters like production of reactive oxygen species by head kidney leukocytes and plasma total immunoglobulin levels did not vary with the treatment. Serum complement activity in both β-carotene groups and the vitamin-containing astaxanthin group were significantly higher than both the control fish. Serum lysozyme activity in the vitamin-containing β-carotene and astaxanthin groups were significantly different from both control groups. Phagocytic activity was also high in the vitamin-containing β-carotene and astaxanthin groups compared with the controls. For phagocytic index, in addition to the foregoing groups, the vitamin-containing canthaxanthin group gave better results compared with the controls. The vitamin-containing astaxanthin and β-carotene groups also exhibited better nonspecific cytotoxicity for the peripheral blood lymphocytes at all effector-to-target ratios. Thus, among the carotenoids studied, β-carotene and astaxanthin elevated humoral factors such as serum complement and lysozyme activity, as well as cellular factors such as phagocytosis and nonspecific cytotoxicity. In the presence of the vitamins the carotenoids exerted a greater influence on the bio-defense mechanisms of rainbow trout.
    • Article

      Rapid wound healing in African catfish, Clarias gariepinus, fed diets supplemented with ascorbic acid 

      G Erazo-Pagador & MS Din - The Israeli Journal of Aquaculture-Bamidgeh, 2001 - Society of Israeli Aquaculture and Marine Biotechnology
      Wound healing in African catfish, Clarias gariepinus, fed diets supplemented with ascorbic acid was studied under laboratory conditions. Fish weighing approximately 80-110 g were stocked in 500 l aquaria in a static water system and fed one of five test diets containing different levels of microencapsulated ascorbic acid (0, 0.06, 0.10, 0.30 and 0.70 g AsA/100 g feed). After two weeks, all experimental fish were wounded by making a 1 x 1 cm dorso-lateral incision above the lateral line of the fish. Wounded tissues were sampled for histopathological analysis 4, 8, 24, 48 and 96 hours, 6, 8, 10, 12 and 14 days after making the incision. There were significant differences in weight gain, specific growth rate (SGR) and feed conversion ratio among the dietary treatments. Weight gain and SGR of fish fed the ascorbic acid free diet were lower than those of fish fed diets supplemented with ascorbic acid. The wound healing response showed a direct correlation to ascorbate level in the diet. Fibroblasts were present at 96 h irrespective of the ascorbic acid level. As 14 days, fish fed no ascorbic acid had some regeneration of muscle tissues, whereas fish fed diets containing supplemental ascorbic acid had a normal epidermis, dermis and muscle structure. There was no mortality during the experimental period, and fish fed ascorbic acid free diets did not exhibit any deficiency signs. Results of this study indicate that about 0.10-0.70 g AsA/100 g feed is needed for wound repair in African catfish.