Вплив трематодної інвазії на основні трофологічні показники ставковиків підроду Peregriana

Abstract

З’ясовано величини середньодобового раціону, засвоюваності їжі та тривалості її проходження через травний тракт ставковиків підроду Peregriana для різних груп їх кормових ресурсів рослинного корму та алохтонного матеріалу. Встановлено, що трематодна інвазія викликає збільшення значень основних трофологічних показників для всіх видів корму.

Определены величины среднесуточного рациона, усвояемости корма и продолжительности его прохождения через пищеварительный тракт у прудовиков подрода Peregriana для разных групп его кормовых ресурсов – растительного и аллохтонного материала. Установлено, что трематодная инвазия вызывает возрастание величин основных трофологических показателей для всех видов корма.

The most common Lymnaea (5 species) in the fauna of Ukraine in general and mentioned it region in particular were the material for this work. They are part of the subgenus Peregriana genus Lymnaea (L. peregra (O. F. Müller, 1774), L. ovata (Draparnaud, 1805), L. balthica (Linné, 1758), L. fontinalis (Studer, 1820), L. patula (Da Costa, 1778)). Comparing the values of the average daily ration for the different types of food, it can be confirm that uninfected Lymnaea the most willingly consume the leaves of Alísma. The molluscs eat less willingly the macerated leaves of poplar - the value of average daily ration for this type of food is from 1.19 to 3.52%, which is less than the value of the average daily ration for Potamogeton leaves (from 1.69 to 4.56%) and much less the value of given magnitude of the stems of water lilies (from 3.31 to 5.06%) (picture). This can be explained by the fact that the leaves of poplar, even macerated, have high mechanical strength. Although in this case, of course, are important and other physical and biochemical characteristics of the forage organisms. A sharp increasing in the value of the average ration for all kinds of food takes place in infected Lymnaea. For the stems of water lilies in L. fontinalis this index especially increasing (3.3 times). This can be explained by the adaptation of the molluscs to the harmful effects of the parasites in the way, when the level of general metabolism is increasing in hosts. This is evidenced by accelerating their rhythm in heart rate, increase heat emission and oxygen consumption. High using of the reserves of the energy substrates compensated by growth of amount of consumed food. It was noticed that the change in the value of the daily food intake depends on the intensity of infestation and with strong contamination, may increase in 81 - 93.6 times. Investigations found that the length of the passage of food through the digestive tract in Lymnaea subgenus also depends on the type of food objects. It was revealed that the smallest time of the passage of food the leaves of Alisma, making an average of 154,76 ± 16,31 min. In infected Lymnaea take place a sharp slowing of the transit time of food (from 1.3 times to leaves of poplar L. patula, 2 times for leaves of Potamogeton L. peregra). Lengtheningin of the time of the passage of food through the digestive tract may contribute to a more complete digestion, its better digestion and absorption of nutrients. Thus, moluscs try to compensate the harmful effects of parasites on their organism. It was established that the value of food digestibility also depends on its type. The lowest value of this index in uninfected moluscs noted for allochthonous material of plant origin (poplar leaves), an average of 42,34 ± 5,02%. The highest digestibility of the food observed in L. peregra for leaves of Alísma - 65,13 ± 7,15%. Also it was marked a regular growth of the value of this index in infected animals. For example, it was marked the greatest growth for leaves Potamogeton (2 times in L. peregra), slightly less - for leaves of poplar (1.3 times in L. patula). It is observed the increasing of the trofological values of all indexes for all kinds of food for moderate trematode infestations, that contributes to the intake of moluscs organisms sufficient number of food material and its full absorption. This is an important physiological adaptation, which allows to Lymnaea to compensate to some extent the harmful effects of the parasites on their organisms.