Grass Carp Tissues Research Articles

Total mercury and mercury species in birds and fish in an aquatic ecosystem in the Czech Republic

Total mercury and mercury species (methylmercury-MeHg, inorganic mercury – Hg 2+) were determined in the aquatic ecosystem Záhlinice (Czech Republic). Four tissues (muscle, intestines, liver and kidney) of three bird species – cormorant, great crested grebe and Eurasian buzzard, muscle tissues of common carp, grass carp, northern pike, goldfish, common tench, perch and rudd, aquatic plants (reed mace and common reed), sediments and water were analysed. Relative contents of MeHg (of total Hg) were in the range from 71% to 94% and from 15% up to 62% in the muscle and intestines and in liver, respectively, for all birds. Statistically significant differences were found between contents of MeHg in liver tissues of young and adult cormorant populations ( F 4.60 = 56.71, P < 10 −5). Relative contents of MeHg in muscle tissues of fishes were in the range from 65.1% to 87.9% of total Hg.

Purification and immunochemical analysis of lactate dehydrogenase (LDH) isozymes of grass carp ( Ctenopharyngodon idella)

By chromatography and other techniques, LDH-A 4, LDH-B 4 and LDH-C 4 were purified from the white skeletal muscle, heart and liver tissues of grass carp ( Ctenopharyngodon idella), respectively. Their corresponding antibodies were prepared from rabbits immunized with purified LDH isozymes. The LDH composition and immunochemical properties were determined by using a combination of immunoprecipitation with starch gel electrophoresis. The LDH isozymes of grass carp are encoded by three gene loci: Ldh-A, Ldh-B and Ldh-C. The physicochemical properties of LDH isozymes were analyzed, including the molecular weight, amino acid composition, Km and substrate concentration, pH and temperature optima, and inhibitor concentration for denaturation. The immunochemical specificity with other freshwater fish demonstrated that the antibodies against grass carp LDH isozymes have no species specificity. Therefore, they could be applied in the identification of the subunit composition of LDH isozyme of other fish species.

魚類のアミラーゼ, &amp;alpha;-および&amp;beta;-グルコシダーゼ, &amp;beta;-ガラクトシダーゼの分布

The activities of amylase, α- and β-glucosidase, and β-galactosidase in the tissues of carp, Cyprinus carpio, crucian carp, Carassius carassius, grass carp, Ctenopharyngodon idellus, rainbow trout, Salmo gairdnerii, silver carp, Hypophthalmichthys molitrix, tilapia, Tilapia nilotica, and yellowtail, Seriola quinqueradiata, were investigated to see the relation between the feeding habits and the distribution of the enzymes. The species exhibiting the strongest amylase activity of the digestive tracts is crucian carp followed by grass carp, tilapia, carp, and silver carp. Very weak or negligible activities of amylase are found in the digestive tracts of rainbow trout, eel, and yellowtail. These results may support the concept that the amylase activity of the digestive tracts depends on the feeding habit of fish. The liver and spleen of the herbivorous and the omnivorous also show the strong amylase activities, while the carnivorous does not. The activities of α-glucosidase in the tissues of grass carp, the herbivorous, are much stronger than those of eel, the carnivorous. On the other hand, the apparent correlation between the feeding habits and the activities of β-glucosidase is not found even with the digestive tracts. The activities of β-galactosidase in the digestive tracts are stronger in the herbivorous and the omnivorous (except the carp) than in the carnivorous. The liver, kidney, and spleen have also the high activities of β-galactosidase. The intracellular distribution of β-galactosidase in the tissues of fish were confirmed by the histochemical investigations.