Wpływ żywienia na aktywność aminopeptydazy i niespecyficznej esterazy w układzie pokarmowym sandacza (Sander lucioperca L.)

The pike-perch (Sander lucioperca L.) at the age of 18 days were fed for 21 days using three different diets: Agio Norse (An), casein-gelatin (Cas), cod meal with gelatin (Mac) and nauplius Artemia salina (Art - control diet). On the last day of the experiment, fish fed Art and An diets had the statistically significant highest body mass, length, and survival. On the last day, the highest aminopeptidase activity in the anterior intestine and posterior intestine was registered in fish fed nauplius Artemia salina. The lowest activity of this enzyme in the anterior intestine was to be found in fish fed with Cas diet, while there was no difference between among groups in the posterior intestine. The non-specific esterase activity was registered in the stomach, liver, anterior intestine as well as in the posterior intestine. The lowest activity of this enzyme in the stomach was observed in the pike-perch fed with the Cas diet. In the anterior intestine, the highest activity was registered in fish fed with Art, and the lowest - on the Cas and Mac diet. The results of the current research prove that feeding the pike-perch An diet has a positive effect of the survival of the pike-perch, their growth rate and the activity of the enzymes. By contrast, feeding pike-perch Cas and Mac diets did not satisfy nutritional needs of fish, resulting in their low survival, growth rate and low activity of the enzymes examined.Wpływ żywienia na aktywność ami-nopeptydazy i niespecyficznej esterazy w układzie pokarmowym sandacza (Sander lucioperca L.). Sandacze (Sander lucioperca L.) w wieku 18 dni były żywione przez 21 dni trzema dietami: Aglo Norse (An), kazeina-żelatyna (Cas), mączka z dorsza z żelatyną (Mac) i naupliusami Artemia salina (Art - dieta kontrolna). Ostatniego dnia doświadczenia ryby żywione Art i An miały statystycznie istotnie większą masę i długość ciała oraz przeżywalność. Ostatniego dnia doświadczenia najwyższą aktywność aminopetydazy w jelicie przednim i tylnym stwierdzono u ryb żywionych naupliusami Artemia salina. Najniższą aktywność tego enzymu w jelicie przednim stwierdzono u ryb żywionych dietą Cas, w jelicie tylnym zaś nie stwierdzono różnic między grupami doświadczalnymi. Aktywność niespecyficznej esterazy stwierdzono w żołądku, wątrobie, jelicie przednim i tylnym. Najniższą aktywność tego enzymu w żołądku obserwowano u sandaczy żywionych dietą Cas. W jelicie przednim najwyższą aktywność stwierdzono u ryb żywionych Art, natomiast najniższą u ryb żywionych Cas i Mac. Wyniki obecnych badań potwierdzają, że żywienie sandaczy dietą An korzystnie wpływa na przeżywalność, tempo wzrostu ryb i aktywność enzymów. Żywienie sandaczy dietami Cas i Mac powodowało natomiast niską przeżywalność ryb oraz tempo wzrostu, a także niską aktywność badanych enzymów= dcfv

Effects of feeding commercial diets on the development of juvenile crucian carp Carassius carassius: digestive tract abnormalities

Wild-living populations of the crucian carp Carassius carassius, a cyprinid fish of European freshwaters, have decreased in recent years, likely due to increasing competition presented by invasive species. Several initiatives have been launched in an attempt to reintroduce this fish back into its natural habitat, but these approaches require the use of crucian carp fry reared under controlled conditions, and the use of popular and inexpensive commercial diets has been found to result in developmental abnormalities. The aim of the current study was to analyse the impact of feeding juvenile crucian carp either natural food (Chironomidae sp. larvae) or 2 commercial diets, with a focus on the intestinal development of these fish. Histological analysis revealed significant pathologies in the alimentary tracts of fish fed both commercial diets; these included lowered hepatocyte and enterocyte proliferation, as well as shortened intestinal folds. Furthermore, the digestive enzyme activity patterns suggested a physiological state close to malnutrition. This study confirmed that basic commercial diets (at least the 2 applied) are not recommended for the rearing of crucian carp juveniles, even though initial growth rates of the fish might suggest otherwise

The effect of dietary lipid level and composition on growth, survival, and development of the digestive system of larval sneep, Chondrostoma nasus (L.)

Background. Rearing larval fish under laboratory conditions requires the use of appropriate artificial diets that fully replace natural food. Up till now, no starter has been developed for cyprinid rheophilic fish larvae, and these fish are therefore fed diets developed for other fish species. The present study was undertaken to evaluate the effects of diets of different protein-, lipid-, and fatty acid compositions on growth, survival, and changes in the digestive system during larval development of sneep (nase), Chondrostoma nasus (L.), from hatching until the juvenile stage. Materials and methods. From day 4 until day 21 post-hatch, sneep larvae were fed, Artemia nauplii and three starters: Nutra AB 3.0 (NU), Perla plus (PP), and Perla larva proactive (PL). Each experimental treatment was run in triplicate. On day 21 of the experiment, samples of fish were taken for size measurement, histological and morphometrical examination, and fatty acid analyses. Results. The fish fed Artemia exhibited the highest growth rate and survival. Among the groups fed artificial diets, the highest survival and growth were observed in NU group, while PL group showed the worst results (P < 0.05). Comparison of the fatty acid composition in the diets and fish bodies revealed that the levels of n-3 PUFA were considerably higher in the bodies of fish fed starters than in the diets themselves, while concentrations of n-6 PUFA in the PP and PL groups were lower in fish than in diets. The NU diet showed the highest n-3 : n-6 ratio (5.54), while PP had the lowest. The highest MUFA : PUFA ratio occurred in Artemia nauplii and the lowest in the PP diet. Histological observations revealed the presence of supranuclear lipid vacuoles in the enterocytes of the middle intestine section of Artemia-fed larvae. No such vacuoles were found in fish fed artificial diets. Morphological changes in the livers of fish fed various diets involved hepatocyte size and cytoplasm area containing glycogen and lipids. Conclusion. Among the artificial diets, Nutra was the most appropriate for rearing sneep larvae. The results revealed that sneep larvae are capable of elongating and desaturating linolenic- and linoleic acids into longer-chain fatty acids

Aquaculture as a potential tool to improve the status of rheophilic cyprinid fish in Poland - status and perspectives of research

Akwakultura jako narzędzie poprawy statusu karpiowatych ryb reofilnych w Polsce – stan i perspektywy badań. Ekosystemy śródlądowych wód płynących na skutek przekształceń o charakterze antropogenicznym są obecnie jednymi z najbardziej zmienionych i zagrożonych środowisk naturalnych. Ichtiofauna, jako istotny element biosystemu, również podlega tym zmianom. W efekcie, od wielu lat obserwuje się zmniejszenie liczebności ugrupowań ryb zasiedlających rzeki. Karpiowate ryby reofilne są ważnym składnikiem ichtiocenoz rzecznych. Ze względu na znaczenie środowiskowe, ale również gospodarcze, od wielu lat są obiektem zainteresowań zespołów badawczych w Polsce. W latach osiemdziesiątych XX wieku rozpoczęto programy badawcze ukierunkowane na opracowanie metod rozrodu oraz wychowu materiału zarybieniowego tej grupy ryb. Badania te zakończyły się sukcesem naukowym, a także aplikacyjnym. W wyniku ponad dwudziestoletnich zabiegów nastąpiła poprawa statusu niektórych opisywanych gatunków w zakresie stopnia ich zagrożenia. Obecnie istnieje konieczność kontynuowania intensywnych działań zmierzających do ochrony i odbudowy populacji tych gatunków ryb reofilnych, których status nie uległ poprawie. Jest to możliwe między innymi dzięki opracowaniu innowacyjnych biotechnik w akwakulturze. Mimo istnienia wielu zagrożeń, akwakultura karpiowatych ryb reofilnych opracowana na wynikach badań naukowych może stać się w większym zakresie niż obecnie ważnym elementem nowoczesnej akwakultury w Polsce, wspierającej działania na rzecz ochrony i poprawy zasobów przyrodniczych oraz zachowania różnorodności biologicznej wód płynących.Aquaculture as a potential tool to improve the status of rheophilic cyprinid fish in Poland – status and perspectives of research. Ecosystems of inland waters are now among the most altered end endangered natural environments. This is caused by anthropogenic transformations. Fish fauna, which is an important element of biosystem, is also a subject of these changes. As a result, there has been a reduction in the size of fish populations in habiting the rivers for many years. Rheophilic cyprinids are an important component of river ichtyocenoses. Due to their environmental as well as economics importance cyprinids have been the object of interest of research teams in Poland for many years. In 1980s, there were research programs launched in Poland. These programs were aimed at developing methods of breeding and rearing of stocking material of this group of fish. These studies, finished with a scientific as well as application success. As a result of over 20 years of treatment the status of these species has improved as it comes to the degree of them being endangered. Nowadays, intensive efforts are being continued. These efforts are aimed to protect and rebuild rheophilic fish species. This is done through the development of innovative biotechniques in aquaculture. Despite many threats, rheophilic cyprinid aquaculture fish based on scientific research may become a vital element of both modern and innovative aquaculture in Poland in greater extent than it is currently. These can also lead to environment protection, improvement of natural resources as well as conservation of rivers biodiversity

Typology of the natural landscape in the Pinczow region

The study proves that the structure and functioning of landscape in the researched area resembles in many respects polygenetic highland and medium-mountain areas of Western Europe, whose contemporary diversity is determined by the following factors: (underground) geological structure, genetic type of Quaternary deposits, and - in some cases - erosion (Ostaszewska, 1987). It should also be emphasised that, similarly to other, "old" lithogenic landscapes, interpretation of geological features of the Pińczów Hummock stili remains a challenge, while some phenomena (particularly those related to the role of periglacial processes in the formation of contemporary landforms) even today defy satisfactory explanation. The outlined process of interdependence between the components and spatial constituents of the landscape in the Pińczów region is solely based on the findings of field research. In the future, it should be supplemented by a more thorough lithological examination and information on the contemporary (if any) activity of tectonic structures (the town chronicles indicate that the last recorded earthquake took place in the 18th century). The only method allowing to properly characterise this highly complicated landscape seems to consist in preparing a more detailed field documentation (especially making the drilling network more dense). Although rather painstaking, this traditional method of geographic research prevents the researchers from falling into the trap of "easy generalisations", of which geoecologists studying the landscapes of old mountains and highlands are frequently accused, and quite rightly so (Cf. Semmel, 1996)