Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 13

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  larval development
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The aim of present study was to evaluate the effects of five experimental starters on the growth rate, survival, development, and morphological changes in the digestive systems of common carp, Cyprinus carpio L., larvae reared under controlled conditions. The starters tested were based on fish hydrolysate and blood meal (diets K, KL, and KLP), fish meal and blood meal (diet KR), and fish meal, blood meal, and fish hydrolysate (diet KHR). Starters KL and KLP were supplemented with intestine lyophilisate obtained from market-sized carp (as a source of digestive enzymes) while a probiotic (mixture of lyophilized lactic acid bacteria) was added to starter KLP. Start-feeding common carp larvae of an average body mass of 2.32 mg and total length (LT) of 6.58 mm were used for the test. The stocking density per tank (volume of 20 dm3) was 100 fish. After 14 days of feeding, the highest average survival (62.9%) was obtained on the KLP diet, while the lowest (11%) was noted on the KR feed. The body total length of carp larvae ranged from 7.83 mm (KR diet) to 8.77 mm (KL diet). In the K, KL, and KLP groups, the final body mass of carp larvae was 48-49 mg, while in the KR and KHR it was 22 mg. Normal digestive tract development was observed in the carp fed the KL and KLP diets.
7
84%
A detailed account of the development of skeletal and some soft−tissue structures is based on 171 fossil tadpoles and metamorphosing froglets of Palaeobatrachus sp. from the Late Oligocene of the Czech Republic (locality Bechlejovice). Their exceptionally good preservation resulted from fossilization in diatomites. The fossil developmental series was compared with normal development of the contemporary anuran Xenopus laevis (Pipidae) represented by cleared and stained (alizarin/toluidin−blue) whole−mount specimens. The comparison revealed that in spite of differences in the sequence of ossification and its timing (e.g., ossification of the otic capsules and ribs was retarded in Xenopus whereas dermal ossification was retarded in Palaeobatrachus), in the number of free ribs, and in composition of the sacral region (the synsacrum in Palaeobatrachus involves two posterior presacrals, whereas there is a single sacral in Xenopus), both genera were similar in great number of anatomical features that appear during development. The most important difference is the shape of vertebral centrum (procoelous in Palaeobatrachus, opisthocoelous in all Pipidae) which is formed in comparatively early developmental stages. A view that could result from anatomical comparisons is that Palaeobatrachus could be derived from the Pipidae, but this is doubtful due to biostratigraphic and palaeogeographic discrepancies. The earliest palaeobatrachids were recorded from the Late Cretaceous of Europe but pipids could not invade northern continents after the Early Cretaceous when the Tethys Sea prevented interchanges of anuran faunas. Also, all palaeobatrachids retain primitive anatomical features (e.g., five pairs of ribs) that were more derived even in the earliest pipids from the Lower Cretaceous of Israel.
8
84%
A developmental series of nearly 250 tadpoles of Shomronella jordanica from the Early Cretaceous (Hauterivian) of the Shomron (Samaria) region of central Israel, a small collection (12) of Thoraciliacus rostriceps tadpoles from the Early Cretaceous (Aptian) of Makhtesh Ramon, Israel, and 13 tadpoles from the Late Cretaceous (Campanian/Maastrichtian boundary) of Stompoor, Marydale, South Africa were studied. These were compared with published data on the development of Paleogene (Middle Eocene–Early Oligocene) pipids from Patagonia, and with normal development of the contemporary pipid frog Xenopus. The comparisons of the developmental series of the Cretaceous and contemporary pipid frogs provided data on changes in the developmental pattern, namely of the degree of ossification and other developmental events. In general, it seems that ossification has become considerably delayed in the course of pipid evolution, whereas most anatomical features typical for free living pipid larvae were well established as early as in the Early Cretaceous. Comparisons with the developmental series of specimens from the Late Oligocene Palaeobatrachidae (closely related to the Pipidae) from Bechlejovice near Děčín, Czech Republic revealed that some morphological differences between the two families might be explained by their developmental mode (e.g., formation of the opisthocoelous vertebral centrum in Shomronella). The uncinate process on three anterior pairs of ribs in Shomronella is the character retained in primitive anurans, and indicates close phylogenetic relations of early pipoids to discoglossoids.
This work proposes modifications to the existing system for identifying the steps of embryonic and larval development in fish. The term “compensatory phase of development” is proposed for the phase from hatching to the first intake of food. Both the new designations of these steps and the new name of this phase do not require a declaration of whether the hatched individual is considered to be an embryo or a larva, something that has been, to date, a matter of dispute. Unification will allow for the wider use of the new nomenclature, and make easier the comparison of results. This work examines the influence of the thermal history during the embryonic period (temperatures of 20, 24, 28, and 32°C) on later development, growth, and survival of common carp, Cyprinus carpio L., and grass carp, Ctenopharyngodon idella (Val.) larvae, at a constant temperature of 23°C. It was confirmed that the optimal temperature ranges for the embryonic development of common carp and grass carp are higher than those currently applied widely in practice of 18-22°C and 21-26°C, respectively. Based on the evaluation of the development, growth, and survival of the larvae, it was determined that the optimal temperature for embryonic development is 26-28°C for the common carp and 32°C for the grass carp. It was confirmed that even a short-term increase in temperature from 20°C to 24°C during the compensatory phase has a positive influence on subsequent common carp larvae growth.
Investigations on the effect of food on length of larval development of Macrolophus melanotoma were carried out in the Department of Plant Protection Methods, Poznań University of Life Sciences in 2004–2006. It was found that the length of complete larval development depended on the type of fed food. The shortest period of larval development of the predatory bug was recorded for larvae’ feeding on gerbera leaves and at the same time additionally fed with sterile eggs of moth Anagasta kuehniella (14.5 days) or Sitotroga cerealella (15.5 days). When the predator was feeding on gerbera leaves infested by Trialeurodes vaporariorum or Tetranychus urticae the length of larval development was significantly longer and amounted to about 20 days. When M. melanotoma was feeding strictly on gerbera leaves 100% mortality was recorded.
The artificially made kernels from ground wheat grain, commercial wheat starch and wheat proteinaceous α-amylase inhibitors in different proportions were used as feed for adults of the granary weevil (Sitophilus granarius L.). In the case of larvae of the confused flour beetle (Tribolium confusum Duv.) and the Mediterranean flour moth (Anagasta kuehniella Zell.) the friable feed mixture were used. The survival of S. granarius adults has not been correlated with the soluble proteins extracted from wheat and amylolytic activity located in this protein fraction. On the other hand the weight of dust (the index of feeding intensity) produced during feeding has depended on the presence of α-amylase and trypsin inhibitors in wheat-based feed. A. kuehniella larvae have not developed at all on feed consisted of 50% wheat starch and 50% of crude a-amylase inhibitors from wheat. The same feed has caused 15.1 days of extension in development time of T. confusum larvae. lt attests to specific native enzymatic apparatus existing in alimentary canals of three damaging grain species which can overcome some obstacles even if extremely highly active insect α-amylase inhibitors were present in feed. However, the sufficient nutrient should be available in feed compounds. Nevertheless, some reduction of insects population can be expected.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.