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1.
Summary The aim of this study was to assess the effects of developmental events, occurring in fish during the first weeks after hatching, on the quantity and quality of the ingested food and on growth. The investigation was carried out with the larvae and juveniles of Rutilus rutilus, the single cyprinid species occurring in an oligotrophic subalpine lake in Tirol, Austria. Comparison between availability of prey in the water and gut contents suggests that the selection of food by the young fish is strongly influenced by developmental processes. For example, the prevalence of indigestible phytoplankton in the gut of young larvae can be taken as a sign of the not yet fully developed sensory and locomotory capacities of the young fish (El-Fiky et al. 1987). Furthermore, quantitative and qualitative changes in the gut contents correlate strongly with changes in the form and relative length of the gut, but reflect only weakly the availability of prey in the water. In the Seefelder See population of R. rutilus the switch from a phytoplankton to a cladoceran dominated diet is accompanied by an increase in relative growth rate by nearly one order of magnitude (Wieser et al. 1988). 相似文献
2.
The aim of this paper is to contribute to the knowledge on the feeding habits of larvae and juvenile Pleuragramma antarcticum in the western Ross Sea. In summer, the diet of P. antarcticum postlarvae (8–17 mm) was dominated by calanoid eggs (35.5%), Limacina (32.1%) and tintinnids (17.6%), while the principal food of juveniles consisted mainly of copepods (98.2%), with Oncaea curvata being the most abundant (85.1%) and the most frequently consumed prey. The food composition of P. antarcticum postlarvae (24–29 mm), collected in spring, suggest that they fed actively under the sea ice. Stephos longipes, Harpacticus furcifer and Paralabidocera antarctica sea ice copepods represent, in all their different developmental stages, the most abundant biomass food in Terra Nova Bay
in this period. Our results therefore suggest that the diet of younger Pleuragramma specimens shifted in prey composition from the first summer to the following spring. This study draws attention to the key
role of the copepod, P. antarctica, in the food web of Terra Nova Bay.
This article belongs to a special topic: Five articles coordinated by L. Guglielmo and V. Saggiomo appear in this issue of
Polar Biology and are a result of a workshop on Sea-ice communities in Terra Nova Bay (Ross Sea) held in August 2007 in Capo
Calavà, Messina, Italy. 相似文献
3.
Annie Mercier Meredith Schofield 《Journal of experimental marine biology and ecology》2011,396(2):207-215
While epibiotic associations between macrobenthic invertebrates are common, the role they play in the feeding ecology of intervening species is often incompletely understood. The diets of epibiotic sea anemones Allantactis parasitica and their gastropod hosts were analyzed using digestive tract contents, lipid biomarkers and observations of live specimens in an attempt to detect dietary feedback from the facultative association. Comparisons were made using symbiotic individuals and asymbiotic counterparts collected at depths of 191-627 m from three neighbouring areas in the northwest Atlantic. Gastropods carrying one or two epibionts had higher stomach indices than those harbouring three epibionts or no epibiont. The diet of symbiotic gastropods was also more diversified based on stomach contents and lipid analysis. Among other things, symbiotic gastropods contained four times more lipids and a greater proportion of Σn−3 fatty acids. Gastrovascular cavity content indices of asymbiotic sea anemones were generally lower than those of symbiotic counterparts. Their cavities were more often empty, and their diet less diversified with fewer benthic items, suggesting that foraging of gastropods through the sediments makes more food available to sea anemones living as epibionts. Lipid analysis showed some disparities between symbiotic and asymbiotic sea anemones at the regional scale, including in percent phospholipids and in the proportion of certain fatty acids. Together these findings indicate that mutual protection against predators leads to prolonged and more efficient foraging for gastropods and increased time spent deployed (feeding) in food-rich areas for sea anemones, thus enabling both partners to fully exploit food resources that may be limited at bathyal depths. 相似文献
4.
The functional significance of allometric change in reptiles has received limited attention and the reason for such changes has been regarded as ‘obscure’. In this paper we report data on the Australian Pogona barbata, the eastern bearded dragon, from across their range and review changes in allometric growth among juveniles, and adult males and females and consider the functional relevance of these changes. There were significant differences in the population for mass, tail length, tail width, rear leg length and jaw length. These differences were consistent with differences required in locomotor performance and thus habitat use, together with access to different preferred dietary components. 相似文献
5.
6.
The small intestinal mucosa exhibits a repetitive architecture organized into two fundamental structures: villi, projecting into the intestinal lumen and composed of mature enterocytes, goblet cells and enteroendocrine cells; and crypts, residing proximal to the submucosa and the muscularis, harboring adult stem and progenitor cells and mature Paneth cells, as well as stromal and immune cells of the crypt microenvironment. Until the last few years, in vitro studies of small intestine was limited to cell lines derived from either benign or malignant tumors, and did not represent the physiology of normal intestinal epithelia and the influence of the microenvironment in which they reside. Here, we demonstrate a method adapted from Sato et al. (2009) for culturing primary mouse intestinal crypt organoids derived from C57BL/6 mice. In addition, we present the use of crypt organoid cultures to assay the crypt metabolic profile in real time by measurement of basal oxygen consumption, glycolytic rate, ATP production and respiratory capacity. Organoids maintain properties defined by their source and retain aspects of their metabolic adaptation reflected by oxygen consumption and extracellular acidification rates. Real time metabolic studies in this crypt organoid culture system are a powerful tool to study crypt organoid energy metabolism, and how it can be modulated by nutritional and pharmacological factors. 相似文献
7.
Tympanic temperature (Tty), mean skin temperature (Tsk) and dynamics of sweating were measured in male subjects, performing prolonged, bicycle-exercise. The exercise was performed under thermoneutral environment after the normal-mixed (C) and low-carbohydrate (LCHO) diet. No difference in changes of Tty was observed after the C and LCHO diets. Sweating was triggered much faster after the LCHO diet. The delay in onset and inertia time of sweating was shorter after the LCHO diet. It is concluded that LCHO diet affects the thermoregulatory responses to exercise by acceleration of sweating, without noticeable differences in body temperature. 相似文献
8.
Maat & Van der Velde (1987) have argued that a generalizable relationship exists between dental attrition and caries rates. They postulated a negative correlation between the two variables; lower rates of caries were associated with higher rates of attrition. They based this conclusion upon an analysis of data from a 17th and 18th century Dutch whaling station on Spitzbergen, together with a survey of literature on European populations over the last thousand years. In this paper we present data from two Portuguese Mesolithic sites questioning the universality of those conclusions. We find a consistently positive correlation between the two variables; higher caries rates are associated with higher attrition rates. The solution to this conundrum appears to be that neither caries nor attrition are directly dependent upon each other. Rather, both are correlated with diet. Different series with different dietary regimes will show different relationships between these two variables, each of which will have to be analyzedde novo. 相似文献
9.
Andrew Sillen 《American journal of physical anthropology》1988,76(1):49-60
Elemental analyses of mammalian bone (e.g., strontium-calcium ratios, or Sr/Ca) distinguish between herbivores and carnivores; however, the relationships among herbivores are unclear. To study this question, a modern faunal sample from the Nagupande Tsetse Control Area (Zambezi drainage, Northwestern Zimbabwe) was used. This collection has the advantage of well-established geographical controls in addition to a varied fauna, which includes both bovids and suids. The grazing/browsing dietary status of each species was ascertained by means of isotopic analysis of carbon. Clear differences were seen in the δ13C of grazing and browsing animals; a specialized grazer was found to have significantly lower Sr/Ca than less specialized grazers and browsers. In this study it was also possible to examine differences in Sr/Ca by sex; female warthogs were found to have significantly lower Sr/Ca than males. The variation in certain animal groups was found to be abnormal. Implications for reconstruction of prehistoric human diets using trace-element techniques are discussed. 相似文献
10.
Casadesus G Moreira PI Nunomura A Siedlak SL Bligh-Glover W Balraj E Petot G Smith MA Perry G 《Neurochemical research》2007,32(4-5):717-722
Metabolic alterations are a key player involved in the onset of Alzheimer disease pathophysiology and, in this review, we
focus on diet, metabolic rate, and neuronal size differences that have all been shown to play etiological and pathological
roles in Alzheimer disease. Specifically, one of the earliest manifestations of brain metabolic depression in these patients
is a sustained high caloric intake meaning that general diet is an important factor to take in account. Moreover, atrophy
in the vasculature and a reduced glucose transporter activity for the vessels is also a common feature in Alzheimer disease.
Finally, the overall size of neurons is larger in cases of Alzheimer disease than that of age-matched controls and, in individuals
with Alzheimer disease, neuronal size inversely correlates with disease duration and positively associates with oxidative
stress. Overall, clarifying cellular and molecular manifestations involved in metabolic alterations may contribute to a better
understanding of early Alzheimer disease pathophysiology.
Special issue dedicated to John P. Blass.
Gemma Casadesus and Paula I. Moreira contributed equally to this paper. Aspects of this paper were previously presented in
Neurochemical Research
28, 1549–1552, 2003 and the Journal of Alzheimer’s Disease
1, 203–206, 1999 and were used here with permission. 相似文献