scholarly journals Pattern of energy allocation during the gametogenesis of the asteroid Cosmasterias lurida (Forcipulatida: Stichasteridae) from the Beagle Channel, Ushuaia, Argentina

2017 ◽  
Vol 65 (1-1) ◽  
pp. 197
Author(s):  
Paula F. Cossi ◽  
Claudia C. Boy ◽  
Analía F. Pérez
Keyword(s):  
Energy Density ◽  
Reproductive Cycle ◽  
Energy Content ◽  
Energy Allocation ◽  
Dry Mass ◽  
Subtidal Zone ◽  
Great Decrease ◽  
Pyloric Caeca ◽  
Beagle Channel ◽  
Gonad Mass

Energy allocation patterns during the reproductive cycle of echinoderms may be determined by the different energy requirements of the organisms. In this study, we describe the energy reserves variation in the gonads, pyloric caeca and stomach among the gametogenic stages of a population of Cosmasterias lurida from the Beagle Channel, Argentina. Adult individuals of C. lurida were collected from the subtidal zone of Ushuaia Bay during four seasonal sampling periods (August 2010 to June 2011). Indices, energy density (kJ/g ash-free dry mass) and energy content (kJ) of gonads, pyloric caeca and stomach were determined. Oocytes number and diameter were evaluated. Cosmasterias lurida had a major peak of gonadal index (GI) in mature gonads (M), with a great decrease towards the spawning (PS/PSR) and remature (RM) periods. No variation was observed in the energy density of the gonads (EDG). The energy content of the gonads (ECG) presented a similar pattern to the GI. Thus, the gonadal storage cycle can be explained through the variation in gonad mass more than in its energy density. Females had higher ECG and EDG values than males, which suggest a greater energy contribution in females during the reproductive cycle. The stomach and the pyloric caeca indices, energy density and energy content remained unaltered among the stages. The energy density of pyloric caeca (EDPC) was higher in mature males than in mature females. Likewise, the energy density of the stomach (EDS) was overall higher in males than in females. This inverse pattern between sexes in relation to the EDG may suggest a transference of energy from the pyloric caeca and stomach to gonads during maturate stage playing a storage role for reproduction. Rev. Biol. Trop. 65(Suppl. 1): S197-S206. Epub 2017 November 01. 

Within-population variability in egg characteristics of walleye (Stizostedion vitreum) and white sucker (Catostomus commersoni)

1997 ◽  
Vol 54 (5) ◽  
pp. 1006-1014 ◽  
Author(s):  
T A Johnston
Keyword(s):  
Energy Density ◽  
Energy Content ◽  
Dry Mass ◽  
Stizostedion Vitreum ◽  
White Sucker ◽  
Catostomus Commersoni ◽  
Female Age ◽  
Size And Age Structure ◽  
The Relationship

I examined variation in egg characteristics among individual females of sympatrically spawning walleye (Stizostedion vitreum) and white sucker (Catostomus commersoni) from Lake Manitoba. White sucker produced eggs of greater dry mass and energy content than walleye. Walleye egg dry mass varied between years and was positively related to both female length and age. The relationship between white sucker egg dry mass and female length varied between years. Egg energy density did not vary with respect to female length in either species. Egg energy density varied between years for walleye but not white sucker. Hatching success of walleye eggs was positively related to female age and negatively related to female length adjusted for age. Length and dry mass of walleye larvae at hatch increased with egg dry mass. Results suggest that the quality of eggs produced by walleye and white sucker populations may vary with the size and age structure of the populations and among spawning years.

scholarly journals Seasonal analysis of condition, biochemical and bioenergetic indices of females of Brazilian flathead, Percophis brasiliensis

2013 ◽  
Vol 11 (1) ◽  
pp. 153-162 ◽  
Author(s):  
Karina A. Rodrigues ◽  
Gustavo J. Macchi ◽  
Agueda Massa ◽  
María I. Militelli
Keyword(s):  
Energy Density ◽  
Reproductive Cycle ◽  
Biochemical Composition ◽  
Seasonal Pattern ◽  
Gonadosomatic Index ◽  
Energy Allocation ◽  
Reproductive Period ◽  
Spawning Period ◽  
Different Tissues ◽  
Percophis Brasiliensis

Percophis brasiliensis is a demersal species that constitutes an important resource of Argentine coastal fisheries. Nevertheless, information about bioenergetic dynamic of reproduction has not been reported. Therefore, seasonal variations of condition factors, biochemical composition and energy density of different tissues were analyzed in order to determine the strategy of energy allocation during the reproductive cycle of this species. Condition indices (hepatosomatic and K) showed a seasonal pattern opposite to that observed for gonadosomatic index, which was characterized by higher values during the reproductive period (spring-summer), decreasing at the end of spawning. Biochemical composition of different tissues also showed a clearly seasonality associated to reproductive cycle. Analysis of energy density variation of liver indicates that P. brasiliensis accumulate reserves in winter before reproduction, which later decrease during the spawning season. In contrast, the energy density in muscle did not show significant differences among seasons, indicating that individuals could be also using an external source of energy during spawning. Therefore, it is possible that P. brasiliensis respond to an intermediate strategy of energy allocation, combining characteristics of both capital breeders (stores energy previous to the onset of reproductive activity) and income breeders (acquire energy by active feeding during spawning period).

Fine-scale taxonomic and temporal variability in the energy density of invertebrate prey of juvenile Chinook salmon Oncorhynchus tshawytscha

2020 ◽  
Vol 655 ◽  
pp. 185-198
Author(s):  
J Weil ◽  
WDP Duguid ◽  
F Juanes
Keyword(s):  
Energy Density ◽  
Chinook Salmon ◽  
Temporal Variability ◽  
Energy Content ◽  
Single Point ◽  
Single Species ◽  
Fine Scale ◽  
Temporal Differences ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook

Variation in the energy content of prey can drive the diet choice, growth and ultimate survival of consumers. In Pacific salmon species, obtaining sufficient energy for rapid growth during early marine residence is hypothesized to reduce the risk of size-selective mortality. In order to determine the energetic benefit of feeding choices for individuals, accurate estimates of energy density (ED) across prey groups are required. Frequently, a single species is assumed to be representative of a larger taxonomic group or related species. Further, single-point estimates are often assumed to be representative of a group across seasons, despite temporal variability. To test the validity of these practices, we sampled zooplankton prey of juvenile Chinook salmon to investigate fine-scale taxonomic and temporal differences in ED. Using a recently developed model to estimate the ED of organisms using percent ash-free dry weight, we compared energy content of several groups that are typically grouped together in growth studies. Decapod megalopae were more energy rich than zoeae and showed family-level variability in ED. Amphipods showed significant species-level variability in ED. Temporal differences were observed, but patterns were not consistent among groups. Bioenergetic model simulations showed that growth rate of juvenile Chinook salmon was almost identical when prey ED values were calculated on a fine scale or on a taxon-averaged coarse scale. However, single-species representative calculations of prey ED yielded highly variable output in growth depending on the representative species used. These results suggest that the latter approach may yield significantly biased results.

scholarly journals Do minke whales (Balaenoptera acutorostrata) digest wax esters?

1995 ◽  
Vol 74 (5) ◽  
pp. 717-722 ◽  
Author(s):  
Erling S. Nordøy
Keyword(s):  
Energy Density ◽  
Dry Matter ◽  
General Pattern ◽  
Dry Mass ◽  
Wax Esters ◽  
Gut Contents ◽  
Wax Ester ◽  
Balaenoptera Acutorostrata ◽  
Minke Whales

Mammals are known to utilize wax esters with an efficiency of less than 50%. The purpose of the present study was to examine whether or not minke whales (Balaenoptera acutorostrata), which at times may eat considerable amounts of wax-ester-rich krill, represent an exception to this general pattern. Samples of fresh undigested forestomach, as well as colon, contents were obtained from minke whales (n5) that had been feeding on krill (Thysanoessa inermis) for some time. The samples were analysed for dry mass, energy density, lipid content and the major lipid classes, including wax esters. The concentrations of wax esters were compared with previous estimates of dry-matter disappearance of the same type of prey using anin vitrotechnique, to calculate the dry-matter digestibility of wax esters (DMDwax). Wax esters contributed 21% of the energy and 47% of total lipids in the krill diet. The energy density of gut contents decreased by 50% after their passage from forestomach to the end of the colon. The DMDwaxwas 94·1 (SD 2·8)% (n5). This high DMDwaxand the occurrence of fatty alcohols, one of the products of wax-ester hydrolysis, in faeces show that minke whales are very efficient digesters of wax esters and absorb most of the energy-rich products of this process.

Optimum torrefaction range for Macaw husks aiming its use as a solid biofuel

2021 ◽  
pp. 1-28
Author(s):  
Robson L Silva ◽  
Omar Seye ◽  
Paulo P. S. Schneider
Keyword(s):  
Energy Density ◽  
Mass Loss ◽  
Energy Content ◽  
Residence Times ◽  
Biomass Feedstock ◽  
Severity Factor ◽  
Optimization Criteria ◽  
Residual Biomass ◽  
Solid Biofuel

Abstract Biomass feedstock is broadly available in many countries and a significant amount of residual biomass comes from agriculture and forest crops. This study aims to identify a consistent criteria for optimize Macaw husks torrefaction process maximizing the energy content and minimizing the mass loss. The optimization criteria is based on the Severity Factor (SF), HHVTorrified and ηSolid-Yield. The energy density (ρEnergy) does not provide consistent and indisputable evidence as an optimization criteria; the same applies to Energy-Mass Co-benefit Index (EMCI) and ηEnergy-Yield. This investigation combined few temperatures (180°C, 220°C, and 260°C) with different residence times (20, 40, and 60 min) and found that the optimum torrefaction range for Macaw husk is 220

Influence of cutting management on productivity and nutritional value of perennial grasses

2019 ◽  
Author(s):  
Л. Евстратова ◽  
Г. Евсеева ◽  
С. Смирнов ◽  
А. Камова
Keyword(s):  
Protein Concentration ◽  
Nutritional Value ◽  
Energy Content ◽  
Regional Climate ◽  
Dry Mass ◽  
Perennial Grasses ◽  
Mass Yield ◽  
Smooth Brome ◽  
Cutting Management ◽  
The Republic

В условиях Республики Карелия в 20152018 годах проведены трёхлетние научные исследования по определению оптимальных режимов скашивания и оценке их влияния на продуктивные и качественные характеристики бобовозлаковых травостоев с включением интродуцированных культур Medicago varia Mart. (сорт Таисия) и Festulolium F. Aschers.et Graebn. (сорт ВИК 90). Установлено, что в агроценозах массовая доля люцерны изменчивой при двуукосном режиме скашивания динамично возрастала с 4,029,1 до 34,442,2, а при трёхукосном с 3,927,6 до 48,860,3. Традиционный бобовый компонент Trifolium hybridum L. (сорт Первенец), наоборот, снизил своё участие в травостое с 22,451,4 до 1,315,3 и с 27,440,0 до 0,713,9 соответственно. Фестулолиум доминировал в травостое при трёхкратном скашивании в 1й и 2й годы пользования (56,1 и 69,5) и при двукратном во 2й и 3й годы (58,6 и 54,0). В среднем за 3 года как при двух, так и при трёхукосном режиме скашивания высокие показатели урожайности сухой массы (7,559,13 т/га), энергетической (6,2110,09 тыс. корм. ед./га 79,794,7 ГДж/га) и протеиновой (0,811,31 т/га) продуктивности обеспечили травостои: кострец безостый люцерна изменчивая клевер гибридный фестулолиум люцерна изменчивая клевер гибридный. Рассматриваемые значения превысили контроль (клеверозлаковый травостой) в 1,11,7 раза. Независимо от состава фитоценоза трёхкратное использование травостоев имело преимущество (на 18,661,7) только по сбору сырого протеина. В типичных погодных условиях полевого сезона лучшие результаты получены при двукратном режиме скашивания бобовозлаковых травостоев, а в экстремальных при трёхкратном. Последний обеспечил более равномерное распределение урожая зелёной массы по укосам и высокие показатели питательности корма. The investigations took place in the Republic of Karelia in 20152018. It was aimed to test cutting managements and their influence on grass productivity and quality and determine the optimal one. Legumegramineous ecosystems contained Medicago varia Mart. (variety Taisiya) and Festulolium F. Aschers.et Graebn. (variety VIK 90). The proportion of bastard alfalfa increased from 4.029.1 to 34.442.2 under two cuts, and from 3.927.6 to 48.860.3 under three cuts. The fraction of conventional grass component Trifolium hybridum L. (variety Pervenets) reduced from 22.451.4 to 1.315.3 and from 27.440.0 to 0.713.9, respectively. Festulolium prevailed in the 1st and 2nd years under three cuts (56.1 and 69.5) as well as in the 2nd and 3rd years under two cuts (58.6 and 54.0). Mixtures of smooth brome bastard alfalfa alsike clover festulolium bastard alfalfa alsike clover had the highest dry mass yield (7.559.13 t ha1), energy content (6.2110.09 thousand feed units ha1 79.794.7 GJ ha1) and protein concentration (0.811.31 t ha1). These values exceeded the ones of the control (clovergramineous mixture) by 1.11.7 times. Three cuts provided 18.661.7 more protein. Two cuts gave better results under typical regional climate, but three cuts were advantageous under unfavorable conditions.

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