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The subject of the study was three populations of spinycheek crayfish, Orconectes limosus (Raf.) from lakes Staw Płociczno, Dgał Wielki, and Hańcza. The aspects of the spinycheek crayfish studied were the morphometric characters of females and males, individual absolute fecundity, sex ratio, size structure, density, biomass, and feeding intensity in an annual cycle. It was determined that the body proportions of males in forms I and II differed significantly, while the body proportions of female spinycheek crayfish were similar to those of form II males but different from the body proportions of form I males. The crayfish investigated in the current study had a lower individual absolute fecundity than did spinycheek crayfish of the same body weights from other Polish basins. The crayfish daily food ration exhibited a very strong relationship with the stomach fullness index and water temperature. The empirical formula of this relationship (ln Rd P = 0.397 + 0.094 t + 0.614 ln If) permitted estimating the daily food ration. The crayfish fed most intensely from the May to October period, during which they consumed in excess of 80% of their annual ration. The primary dietary component of the spinycheek crayfish was plant matter. Annually, the crayfish population consumed barely 0.27% of the wet weight of the aquatic vegetation in its range of occurrence.
A total of 12 Limousin bull calves were assigned to two feeding groups (6 animals per group) analogous in terms of body weight. Bulls were reared during calfhood with suckler cows and then fed indoors with farm-produced feeds (silages, hay, concentrates) to obtain a body weight gain of approximately 1000 g/day. The basic bulky feed was maize silage (fed ad libitum), supplemented with meadow hay (1 kg/day), and different amounts (according to group) of concentrate (kg/100 kg body weight): 1.0 (group KK-I) or 0.6 (KK-P). The study showed that compared to semi-intensive feeding, intensive feeding of Limousin bulls in the finishing period with diets containing maize silage, meadow hay and concentrate had a more favourable effect on fattening traits, slaughter traits, economic efficiency of feeding and fatty acid profile in the intramuscular fat, n-6/n-3 PUFA ratio and total cholesterol content of the longissimus muscle.
This paper presents the results of studies on the feeding and growth of Siberian sturgeon in the first year of life in monoculture in earthen ponds. The digestive tracts of the fish contained the following orders of invertebrate fauna: Cladocera, Coleoptera, Copepoda, Diptera, Heteroptera, Mollusca, Oligochaeta and Trichoptera. Diptera and Cladocera dominated. Small amounts of Copepoda, Heteroptera, Mollusca and Trichoptera were also noted. The average indexes of weight contribution reached the highest values (1.09 - 1.70 g) in the spring-summer season, while the value in the fall sample was 1.41 g. The highest values of frequency of occurrence (100%) of the dominant Cladocera and Diptera in the food and of feeding intensity (179 - 275‱) also occurred in the spring-summer season. The highest values of the percentage indexes (> 50% - eudominants) were reported for plankton crustaceans from the order Cladocera in spring and summer. After the spring sturgeon had adapted to the new environmental conditions, a clear increase in the growth rate was observed, and after the water temperature dropped below 13ºC growth stopped.
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.
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