Growth of the brittle star Ophiura sarsii sarsii in Funka Bay,Hokkaido, Japan

Fisheries Science - The brittle star Ophiura sarsii with a disc diameter (DD) of less than 9 mm is an important prey item for flathead flounder Hippoglossoides dubius in Funka...     

Manageable risks and the demand for food products: the case of oyster

The risk of norovirus food poisoning from oyster consumption can be minimized by consumers, as thorough cooking can destroy norovirus. This paper uses data from 23 prefectures in Japan during 1970–2010 to examine how the demand for oysters responds to this manageable risk. We find that the incidence rate of norovirus has no effect on the price of oysters in prefectures that specialize in oysters for cooking, whereas it has significant negative impacts in prefectures that produce oysters to be eaten raw. These results indicate that consumers respond differently to manageable and non-manageable risks.     

The effect of temperature on environmental DNA degradation of Japanese eel

Fisheries Science - The environmental DNA (eDNA) technique is a convenient and powerful tool to detect rare species. Knowledge of the degradation rate of eDNA in water is important for...     

The use of machine learning to predict acute hepatopancreatic necrosis disease (AHPND) in shrimp farmed on the east coast of the Mekong Delta of Vietnam

Fisheries Science - Predicting the outbreak of disease is essential when managing shrimp farms. Acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio parahaemolyticus is a serious...     

Protective effect of <Emphasis Type="Italic">Ganoderma lucidum</Emphasis> polysaccharide against carbon tetrachloride-induced hepatic damage in precision-cut carp liver slices

The aim of the present study was to investigate the protective effects of Ganoderma lucidum polysaccharide (GLPS) against carbon tetrachloride (CCl₄)-induced hepatotoxicity in vitro in common carp. Precision-cut liver slices (PCLSs), which closely resemble the organ from which they are derived, were employed as an in vitro model system. GLPS (0.1, 0.3, and 0.6 mg/ml) was added to PCLS culture system before the exposure to 12 mM CCl₄. The supernatants and slices were collected to detect molecular and biochemical responses to CCl₄ and PCLS treatments. The levels of CYP1A, CYP3A, and CYP2E1 were measured by ELISA; the mRNA expressions of TNF-α, IL-1β, IL-6, and iNOS were determined by RT-PCR; and the relative protein expressions of c-Rel and p65 were analyzed by western blotting. Results showed that GLPS inhibited the elevations of the marker enzymes (GOT, GPT, LDH) and MDA induced by CCl₄; it also enhanced the suppressed activity of antioxidant enzymes (SOD, CAT, GSH-Px, T-AOC). The treatment with GLPS resulted in significant downregulation of NF-κB and inflammatory cytokine mRNA levels and significant decreases in the hepatic protein levels of CYP1A, CYP3A, and CYP2E1. These results suggest that GLPS can protect CCl₄-induced PCLS injury through inhibiting lipid peroxidation, elevating antioxidant enzyme activity, and suppressing immune inflammatory response.     

Effects of manufacturing factors on the viscosity of a polysaccharide solution extracted from Gagome Kjellmaniella crassifolia

A highly viscous polysaccharide solution was extracted from Gagome Kjellmaniella crassifolia in 20°C water. The eluted sugar concentration was 0.16%, and the extracted carbohydrates consisted of fucoidan, laminaran, and alginate at an approximately ratio of 8.2:0.8:1.0. An increase in the extraction temperature resulted in a less viscous solution, even though the amount of eluted sugar was higher than that obtained at a lower temperature. The most viscous extraction solution was obtained at a neutral pH, with a more acidic or alkaline extraction solution being a less viscous. When the highly viscous polysaccharide solution was heated, the viscosity decreased markedly with increasing temperature. The viscosity of the polysaccharide solution increased after dialysis against water and decreased with the addition of either KCl or NaCl. However, the viscosity was recovered to previous levels by following re-dialysis against water. The removal of divalent cations by EDTA and the re-addition using CaCl₂ or MgCl₂ also caused reversible changes to the viscosity. These characterizations will be useful for widespread applications of viscous K. crassifolia polysaccharides.     

Efficacy of a novel in ovo-attenuated live vaccine and recombinant vaccine against a very virulent infectious bursal disease virus in chickens

Infectious bursal disease (IBD) causes severe economic damage to the poultry industry worldwide. To prevent IBD virus (IBDV) infection, live virus vaccines have been widely used in chickens having wide-ranging levels of maternally derived antibodies. But, the risks of infection with other pathogens because of lesions related to atrophy of the bursa of Fabricius in vaccinated chickens are a concern. To resolve the problems, a recombinant turkey herpesvirus (HVT) vaccine expressing IBDV-VP2 protein (rHVT-IBD) has been developed. However, the induction of neutralizing antibodies by rHVT-IBD against a virulent IBDV might be delayed compared with that by the live IBD vaccine, leading to the high risks of IBDV infection for young chickens. To find the best selection of IBDV vaccine for the onset of immunity, we examine the protective efficacy of a novel in ovo-attenuated live IBDV (IBD-CA) vaccine and the rHVT-IBD vaccine in young chickens challenged with a very virulent IBDV (vvIBDV) strain. We show that the protective efficacy of IBD-CA vaccine was higher than that of the rHVT-IBD vaccine in 14-day-old chickens challenged with the vvIBDV strain, leading to the risk of IBDV infection for young chickens when vaccinated with rHVT-IBD. Our results suggest that farmers should select the best vaccines to maximize vaccine efficacy in consideration of the vaccine characteristics, prevalence levels of IBDV in the areas, and initial MDA levels of the chickens since the attenuated live and recombinant vaccines play a role in the different vaccine efficacies.