Now showing items 1-5 of 5

    • 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.
    • Growth and feed efficiency in mangrove red snapper, (Lutjanus argentimaculatus Forsskal 1775) fed practical diets supplemented with L-ascorbyl-2-monophosphate-Mg 

      MR Catacutan, GE Pagador, E Doyola-Solis, S Teshima & M Ishikawa - The Israeli Journal of Aquaculture-Bamidgeh, 2011 - Society of Israeli Aquaculture and Marine Biotechnology (SIAMB)
      Growth and feed efficiency were determined in red snapper, Lutjanus argentimaculatus (Forsskal 1775), fed diets containing L-ascorbyl-2-monophosphate-Mg (AMP). Fish (13.39±0.08 g) were fed a practical diet without vitamin C supplement for four weeks then stocked in twelve 650-l tanks at 30 fish/tank and fed one of four practical diets containing AMP at 0, 60, 180, or 540 mg/kg dry diet for 17 weeks. Survival rates in all treatments were similar (88.9-98.9%). Fish fed the 0 or 540 ppm diets had inferior final average weights, protein efficiency ratios, and feed conversion ratios than fish fed the 60 or 80 ppm diets (p<0.05). Growth of fish fed the 0 or 540 ppm diets slowed down on day 60 and fish fed the AMP-free diet exhibited clinical signs of vitamin C deficiency with a soft body and a significantly high (p<0.05) hepatosomatic index. Ascorbic acid in brain and liver tissues rose with the level of dietary AMP. Fish fed the 540 ppm diet had significantly lower hematocrit (p<0.05) than fish fed the 60 or 180 ppm diets. Histological analysis of the liver and kidney of fish fed the 180 and 540 ppm diets showed changes indicative of possible toxic effects. Based on growth, feed efficiency, tissue histology, and hematocrit level, AMP at 540 ppm is toxic to snapper. Thus, supplementation of 60 ppm AMP or its equivalent 26 ppm ascorbic acid in practical diets for red snapper promotes optimum growth and feed efficiency and prevents vitamin C deficiency symptoms.
    • Article

      Growth, plasma cortisol, liver and kidney histology, and resistance to vibriosis in brown-marbled grouper, Epinephelus fuscoguttatus fed onion and ginger 

      MJS Apines-Amar, EC Amar & JP Faisan Jr. - Aquaculture, Aquarium, Conservation and Legislation, 2013 - Bioflux
      The health-promoting effects of dietary onion and ginger were studied in brown marbled grouper, Epinephelus fuscoguttatus. An eight-week feeding trial was conducted to evaluate the effects of dietary onion and ginger on growth, cortisol levels, histology and disease resistance in the fish. Five experimental diets were formulated to contain either onion (2%), ginger (2%), β-glucan (1%) or vitamin C (3%) and a control diet (without immunostimulants). Each diet was fed to triplicate groups of fish with an average weight of 10.85±0.69 g. Fish supplemented with either of the immunostimulants exhibited a significantly higher growth compared to the control group. Specific growth rate (SGR) and feed conversion efficiency (FCE) were significantly higher in the onion and ginger-supplemented fish than the control. Cortisol level was higher in the control compared to the immunostimulant-fed groups with onion and ginger-fed fish showing significantly lower cortisol levels. When experimentally infected with Vibrio harveyi, fish fed onion or ginger exhibited significantly reduced mortality when compared with the control and β-glucan, but not when compared with the vitamin C-fed group. Liver sections sampled 4 days postinfection showed no remarkable pathology except for the slight reduction in glycogen granules in the supplement-fed fish. The liver of non-supplemented infected fish showed necrosis, fatty globule deposition, vacuolation, and presence of short rod-shaped bacteria. Kidney sections in the supplemented groups, likewise, did not show significant pathology similar to the uninfected control, whereas those of infected control fish showed necrosis of the tubules and glomeruli resulting in severely altered morphology of the tissues and presence of bacteria in the necrotic areas. As a result of circumventing tissue damage, wound healing was faster in fish supplemented with ginger, onion, and vitamin C compared to the β-glucan and the control groups. This study showed the benefits of onion and ginger in promoting growth and alleviating stress and severity of vibriosis in grouper.
    • Article

      Immune responses of Asian sea bass, Lates calcarifer Bloch, against an inactivated betanodavirus vaccine 

      RV Pakingking Jr., R Seron, LD de la Peña, K Mori, H Yamashita & T Nakai - Journal of Fish Diseases, 2009 - Blackwell Publishing
      Asian sea bass, Lates calcarifer (Bloch), exhibited strong immune responses against a single injection of the formalin-inactivated red-spotted grouper nervous necrosis virus (RGNNV), a betanodavirus originally isolated in Japan. Fish produced neutralizing antibodies at high titre levels from days 10 (mean titre 1:480) to 116 (1:1280), with the highest titre at day 60 post-vaccination (1:4480). When fish were challenged with the homologous RGNNV at day 54 post-vaccination, there were no mortalities in both the vaccinated and unvaccinated control fish. However, a rapid clearance of the virus was observed in the brains and kidneys of vaccinated fish, followed by a significant increase in neutralizing-antibody titres. Furthermore, the vaccine-induced antibodies potently neutralized Philippine betanodavirus isolates (RGNNV) in a cross-neutralization assay. The present results indicate the potential of the formalin-inactivated RGNNV vaccine against viral nervous necrosis (VNN) of Asian seabass.
    • Article

      Surveillance of emerging fish viral pathogens in some Southeast Asian countries 

      G Lio-Po, E Amar, L de la Peña, ZG Orozco, J Faisan, V Suarnaba & DB Tubo - The Israeli Journal of Aquaculture-Bamidgeh, 2009 - Society of Israeli Aquaculture and Marine Biotechnology
      Preventing the transboundary movement of fish viral pathogens in a global environment requires active surveillance. This study examined the presence of three emerging viral pathogens among koi, common, grass, and silver carp in Cambodia, Lao PDR, Myanmar, Philippines, and Vietnam. The studied viruses included koi herpesvirus (KHV), spring viremia of carp virus (SVCV), and grass carp reovirus (GCRV). Detection methods consisted of virus isolation by cell culture, infection assay in naive fish, polymerase chain reaction (PCR), and reverse-transcriptase PCR (RT-PCR). Tissues were collected and pooled from 193 fish samples in Dec. 2004 to Feb. 2005, 406 in Sep. 2005 to Feb. 2006, and 1302 in Oct. 2006 to Feb. 2007. For cell culture, tissue filtrates were prepared from pooled spleens, kidneys, livers, and gills and inoculated onto koi fin (KF-1), grass carp kidney (GCK), and fat head minnow (FHM) cells. For infection assay, tissue filtrates were injected intraperitoneally to healthy, naive common carp. No virus was detected after three cell culture passages and the infection bioassays. One-step and nested-step PCR was used to detect KHV in gills of fish samples. One-step and semi-nested RT-PCR was used to detect SVCV and GCRV in the spleens, kidneys, and livers of fish samples. Samples from all three years from all five countries yielded negative results for all three viruses, indicating that KHV, SVCV, and GCRV were not present in these five countries during the period of the study although KHV outbreaks had been detected in Indonesia, Taiwan, Japan, Thailand, China, and Malaysia.