Helminthes in the Small Intestine of the Common Eider (Somateria mollissima) from the Eastern Murman: Impact on the Host Digestive Activity and Physiological State

In this ecological and physiological study of the common eider (Somateria mollissima) nesting on the coast of Eastern Murman, the species composition of the bird helminth fauna, as well as the infection quantitative parameters, were determined. The common eider small intestine proved to be infected with trematodes of the genus Microphallus; three species of cestodes, namely, Lateriporus teres (Cestoda: Dilepididae), Fimbriarioides intermedia (Cestoda: Hymenolepididae), and Microsomacanthus diorchis (Cestoda: Hymenolepididae); and one species of acanthocephalan, Polymorphus phippsi (Palaeacanthocephala: Polymorphidae). At the sites of F. intermedia and M. diorchis locations within the intestine, the protease activity was reduced while in the foci infected with acanthocephalan P. phippsi, it was, on the contrary, increased. Glycosidase activity in the intestinal mucosa was reduced as compared to the control in birds infected by the cestodes M. diorchis. Hematological indices of the infected individuals were higher than the control parameters.

Inactivation of proteolytic enzymes by cestodes

Inhibitor activity of cestodes from intestines of different hosts (sea birds, salt-water fish, and freshwater fish) was investigated. Alcataenia larina, Arctotaenia tetrabothrioides, Tetrabothrius erostris, T. minor, Wardium cirrosa, Bothriocephalus scorpii, Eubothrium rugosum, and Triaenophorus nodulosus were able to inhibit the activity of the commercial trypsin and activity of proteinase homogenates of the intestinal mucosa of the hosts. It was suggested that the inhibitor produced by the cestodes is specific for trypsin and protects them from the digestive enzymes of the host.

[HEMATOLOGY AND BLOOD CHEMISTRY OF THE HERRING GULL LARUS ARGENTATUS INFESTED BY CESTODES DIPHYLLOBOTHRIUM DENDRITICUM (CESTODA: DIPHYLLOBOTHRIIDAE)]

Hematological and plasma biochemical analyses and parasitological detection were carried out in the herring gull Larus argentatus. Hematological and plasma biochemical parameters in uninfected gulls and gulls infected by Diphyllobothrium dendriticum (Cestoda: Diphyllobothriidae) were compared. Hemoglobin content and numbers of erythrocytes were reduced; numbers of leukocytes and sorption capacity of erythrocytes were improved in blood of the infected herring gulls. Hematological index (eosinophil/lymphocyte ratio) in infected gulls increased 1.8 times in comparison with eosinophil/lymphocyte ratio in uninfected gulls. Metabolic imbalances in herring gulls infected by D. dendriticum were determined. Levels of the total protein, phospholipids, triglyceride, phosphorus, calcium, magnesium and sodium, and the activity of alkaline phosphatase decreased in plasma blood of infected gulls; at the same time, the content of the uric acid, glucose, modified albumin and circulatory immune complex and activities of transaminases and lactate dehydrogenase had increased. It is assumed that the obtained results testify to the appearance of abnormalities in the digestion processes and the activity of immune and circulatory systems caused by the invasion of gulls with D. dendriticum. 375

Diphyllobothrium dendriticum (Cestoda: Diphyllobothriidae) in the Intestinal Tract of the Herring Gull Larus argentatus: Localization and Trophic Parameters

We studied the activities both of digestive enzymes in the small intestine of the herring gull (Larus argentatus) and a tapeworm Diphyllobothrium dendriticum (Cestoda: Diphyllobothriidae) residing in the intestine. It was found that D. dendriticum infects the medial section of the small intestine of the herring gull. Such localization of D. dendriticum is caused by the maximal activity of proteases and glycosidases and by the high rate of membrane and cavitary digestion in this section. The activity of protease and glycosidase in gulls infected with D. dendriticum is decreased. The activity of proteases in the fractions desorbed from the tegument surface of D. dendriticum is significantly higher than that of glycosidases.

[RELATIONSHIPS IN THE "NORTHERN FULMAR (FULMAR US GLACIALIS)--TETRABOTHRIUS MINOR (CESTODA: TETRABOTHRIIDAE)" SYSTEM: PHYSIOLOGICAL ASPECTS]

Relationships between the northern fulmar (Fulmarus glacialis L., 1761) and cestodes Tetrabothrius minor Loennberg, 1893 (Cestoda: Tetrabothriidae) were studied. The results of calculation of the number of tapeworms in different parts (proximal, medial and distal) of bird intestines are represented. Parameters of protein metabolism in the northern fulmar and cestodes T. minor were investigated. Activity of proteases in different parts of northern fulmar intestine and in the strobila of T. minor was determined. Digestion processes occurring on digestive-absorptive surfaces of the intestine of the northern fulmar and of cestodes were studied. Biochemical indices of blood plasma of the northern fulmar were analyzed in relation to the intensity of invasion and the stage parasite maturation. The highest indices of the invasion of the northern fulmar with T. minor were recorded in the proximal part if the intestine. It was shown that the preferred localization of tapeworms in the proximal department of the intestine was determined by abundance of food and high activity of digestive enzymes in this place. Active hydrolysis of proteins in the intestine of the northern fulmar and on tegument surfaces of T. minor occurred mainly during the process of cavernous digestion. To a greater extent, the physiological state of the northern fulmar depended on the intensity of invasion and on the maturation stage of tapeworms.

[Carbohydrate metabolism parameters in the thick-billed murre (Uria lomvia) infested with Alcataenia armillaris (Cestoda: Dilepididae)]

Some aspects of carbohydrate metabolism in noninfested thick-billed murres (Uria lomvia) and those infested with the tapeworm Alcataenia armillaris (Cestoda: Dilepididae) are reported. The findings demonstrate that the intestinal invasion by A. armillaris causes a drop in the activity of digestive enzymes (glycosidases and sacharase) and decreases blood glucose levels and glycogen content in the liver. The main reasons underlying changes in avian carbohydrate metabolism in cestode invasion are suggested.

[Activity of digestive enzymes of thick-billed murre (Uria lomvia) and common murre (U. aalga) invaded by cestodes]

Activities of digestive enzymes (proteases, carbohydrases, acid and alkaline phosphatases) are determined in intestinal mucosa of the thick-billed and common murres Comparative analysis of the obtained results is performed for non-infected and for birds infested by cestodes. It has been established that at invasion by cestode Alcataenia armillaris (Cestoda: Tetrabothriidae), activities of carbohydrase and alkaline phosphatase in intestinal mucosa of the thick-billed murre decreases. Parasitizing of cestodes Tetrabothrius jaegerskieldi (Cestoda: Tetrabothriidae) in intestine of the common murre induces a decrease of saccharase activity. There is studied kinetics of desorption of enzymes from digestive-transport surfaces of the bird intestine. Peculiarities of firmness of enzyme fixation are established on the surface of intestinal mucosa of invaded murres. According to the obtained data, a decrease of the carbohydrase activities in intestine of infested murres is likely to be due to absorption of a part of enzymes hydrolyzing carbohydrates on the surface of cestodes.

[Characteristics of protein hydrolysis on the digestive-transport surfaces of the intestine of the kittiwake Rissa tridactyla and Alcataenia larina (Cestoda, Dilepididae) parasitizing it]

Investigation of the activity of proteolytic enzymes functioning on the digestive-transport surfaces of the intestine of infected and noninfected kittiwakes Rissa tridactyla and cestodes Alcataenia larina (Cestoda, Dilepididae) parasitizing it was conducted. The protease activities depending on the pH values in the intestine of gulls and tapeworms were determined. The dynamics of desorption of enzymes of protein hydrolysis from the surface of the cestodes A. larina and the kittiwake intestine was studied. It was shown that the tapeworm invasion activates the processes of membrane and cavitary digestion of birds. It was determined that the degree of influence of the dilepidid infection on protease activity was defined mainly by the intensity of the invasion.

[Seasonal dynamics of the trematodes fauna in herring gull (Larus argentatus Pontopp.) of Kola Bay]

Trematode fauna of the herring gulls from Kola Bay (Barents Sea) was investigated in March, May, June, and September 2005. The data on the trematode species composition and indices of the invasion of gulls with trematodes are given for each season. It was established, that trematode species composition is increased from spring to summer, and intensity of the gulls' invasion with some trematode species is increased from summer to autumn. Ecological factors causing seasonal differences of the trematode fauna in gulls are discussed.

[Dynamics of physiological parameters in the nestling of black-backed gull Larus marinus experimentally infested by the cestode Microsomacanthus ductilus (Cestoda: Hymenolepididae)]

The effect of the invasion with the cestode Microsomacanthus ductilus on physiological and biochemical processes in black-backed gull Larus marinus was examined. Experimental invasion of the gull nestling by the cestodes has been performed. Dynamics of the protein, lipid, and carbohydrate metabolism in the time history of the invasion was observed, in comparison with noninfested nestling. Increasing of the content of alpha-globulins and decreasing of the content of protein and albumin in the blood plasma of experimentally infested birds were registered to 4th day after invasion. To 7th day after invasion the level of general lipids and phospholipids decreases, while the content of gamma-globulins and modified form of albumin increases. To 10th day after invasion symptoms of intoxication were observed, but some parameters proved to be reverted to normal condition. So, it can be assumed, that the most intensive reorganization of the metabolism in infested birds takes place in the period between 4th and 7th days after infestation. Possible causes of the observed phenomena are discussed.

[Study of protein metabolism of herring gulls (Larus argentatus Pontop.) infected by trematode Himasthla larina (Trematoda: Echinostomatidae)]

The values and dynamics of some indices of protein metabolism were studied in herring gulls Larus argentatus infected with trematode Himasthla larina in natural populations and in experiment. These indices were compared in infected and uninfected birds. Trematode infection considerably affected host protein metabolism irrespective of the age; however, the changes were more pronounced in nestlings. Increased concentration of gamma-globulins, modified albumin, and circulating immune complexes was observed in plasma of infected herring gulls. The experiments demonstrated the most significant changes in protein metabolism of herring gulls 8-11 days after infection with trematode H. larina.