Assimilation Efficiency

2006 ◽  
pp. 207-207
Keyword(s):  
Assimilation Efficiency

Significance of Organic Detritus in the Diet of Larval Lampreys in the Great Lakes Basin

1994 ◽  
Vol 51 (11) ◽  
pp. 2380-2387 ◽  
Author(s):  
Trent M. Sutton ◽  
Stephen H. Bowen
Keyword(s):  
Great Lakes ◽  
Feeding Rate ◽  
Assimilation Efficiency ◽  
Dry Mass ◽  
Great Lakes Basin ◽  
Organic Detritus ◽  
Upper Peninsula ◽  
Sea Lampreys ◽  
Gut Fullness ◽  
Upper Peninsula Of Michigan

Larval sea lamprey (Petromyzon marinus) and northern brook lamprey (Ichthyomyzon fossor) were collected monthly from three streams in the Upper Peninsula of Michigan from May 1992 through May 1993 and larval sea lampreys were collected during summer months from sites throughout the Great Lakes basin. Organic detritus made up most of the diet ash-free-dry-mass (AFDM) throughout the year, averaging 97.79%, with algae (2.12%) and bacteria (0.09%) making up the remainder of the diet AFDM. Assimilation efficiency for AFDM averaged 72% during warmer months and 53% during cooler months (annual mean = 61%). Gut fullness (amount of AFDM in the anterior one-tenth of the intestine) was low (mean = 0.10 mg diet AFDM∙g−1 ammocoete). There were no significant differences in these measures between ammocoetes collected from the Upper Peninsula and those collected throughout the Great Lakes basin. From a laboratory-determined relationship between gut fullness and feeding rate, feeding rate in the field was estimated to be extremely slow, ranging from 4.2 to 5.5 mg diet AFDM∙g−1 ammocoete∙d−1. These observations indicate that larval lampreys efficiently utilize a diet of organic detritus during warmer months when stream temperatures and food quality are more favorable for feeding, digestion, and growth.

Assimilation efficiency for sediment-sorbed benzo(a)pyrene by Diporeia spp.

1993 ◽  
Vol 26 (3-4) ◽  
pp. 209-224 ◽  
Author(s):  
M.J. Lydy ◽  
P.F. Landrum
Keyword(s):  
Assimilation Efficiency

scholarly journals Biochar effect - mediated ammonium transporter genes and GDH may be the core of improvement nitrogen assimilation in cotton seedling

2020 ◽  
Author(s):  
Lei Feng ◽  
Guangmu Tang ◽  
Wanli Xu ◽  
Meiying Gu ◽  
Zengchao Geng
Keyword(s):  
Seedling Growth ◽  
Fine Roots ◽  
Nitrogen Assimilation ◽  
Surface Soil ◽  
Soil Layer ◽  
Assimilation Efficiency ◽  
Seedling Stage ◽  
Nitrogen Efficiency ◽  
Ammonium Transporter ◽  
Cotton Seedling

AbstractBiochar enhancement of nitrogen efficiency in crops is highly essential not only to reduce costs of agricultural production but also to conserve resources, lower energy consumption for products of these fertilizers, strengthen soil health, and eventually helps in slowing climate change; however nitrogen efficiency physiology by biochar effects is not clear. Here, we reported on the morphological, nitrogen metabolism and cytokinin, at seedling stage, under different layers of biochar and limited urea conditions grown in soil culture. Expression profile of miRNAs and AOB was further studied in fine and medium roots. It showed active root absorption area, fresh weight, and nitrogen agronomic efficiency responded significantly under biochar and reduction by 20% urea condition in the surface soil layer. Also, NR and GPT activity in fine roots remarkably increased with cytokinin, but decreased significantly in medium roots, meanwhile both NR and GDH activity did so. GOGAT activity was to be dependent with biochar and urea locations. In addition, AMT1;1, gdh3 and gdh2 in fine roots showed their up-regulation with reduction 20% urea and biochar. It revealed that co-expression of gdh3 and gdh2 in fine roots significantly affected nitrogen assimilation under reduction 20% urea with biochar on surface soil at seedling stage.HighlightsThe co-expression of ammonium transporter gene and GDH induced by biochar effect improves nitrogen efficiency and seedling growth.These data emphasizes the importance of effects of cytokinin on nitrate reductase activity closely related to the position under biochar condition, which is a key element of enhancement nitrogen assimilation efficiency in cotton seedling.Biochar addition applied into 0 to 10cm soil had a more positive effect on seedling growth than that into 10 to 20cm soil layers.

scholarly journals Locusts use dynamic thermoregulatory behaviour to optimize nutritional outcomes

2011 ◽  
Vol 278 (1719) ◽  
pp. 2745-2752 ◽  
Author(s):  
Nicole Coggan ◽  
Fiona J. Clissold ◽  
Stephen J. Simpson
Keyword(s):  
Locusta Migratoria ◽  
Nutrient Use Efficiency ◽  
Assimilation Efficiency ◽  
Thermal Inertia ◽  
Temperature Selection ◽  
Nutrient Use ◽  
Wide Range ◽  
Lower Temperature ◽  
The Cost ◽  
Thermoregulatory Behaviour

Because key nutritional processes differ in their thermal optima, ectotherms may use temperature selection to optimize performance in changing nutritional environments. Such behaviour would be especially advantageous to small terrestrial animals, which have low thermal inertia and often have access to a wide range of environmental temperatures over small distances. Using the locust, Locusta migratoria , we have demonstrated a direct link between nutritional state and thermoregulatory behaviour. When faced with chronic restrictions to the supply of nutrients, locusts selected increasingly lower temperatures within a gradient, thereby maximizing nutrient use efficiency at the cost of slower growth. Over the shorter term, when locusts were unable to find a meal in the normal course of ad libitum feeding, they immediately adjusted their thermoregulatory behaviour, selecting a lower temperature at which assimilation efficiency was maximal. Thus, locusts use fine scale patterns of movement and temperature selection to adjust for reduced nutrient supply and thereby ameliorate associated life-history consequences.

Prey consumption estimates for salmon sharks

2019 ◽  
Vol 70 (6) ◽  
pp. 824 ◽  
Author(s):  
Kaitlyn A. Manishin ◽  
Kenneth J. Goldman ◽  
Margaret Short ◽  
Curry J. Cunningham ◽  
Peter A. H. Westley ◽  
...  
Keyword(s):  
Life History ◽  
Mass Balance ◽  
Marine Mammals ◽  
Extreme Values ◽  
Assimilation Efficiency ◽  
Prey Consumption ◽  
Trophic Levels ◽  
Shark Species ◽  
Top Predators ◽  
Balance Technique

Top predators, such as salmon sharks (Lamna ditropis), can influence the abundance and population structure of organisms at lower trophic levels through direct effects, such as predation mortality, and indirect interactions. As a first step towards better understanding the average annual prey consumption for individual adult salmon sharks, we bracketed consumption estimates using three methods: (1) daily ration requirement; (2) bioenergetic mass balance; and (3) a Bayesian model of shark growth. In the first method, we applied ration estimates for related lamnid shark species that yielded salmon shark estimates of 1461 and 2202kgyear–1. The second method used a mass–balance technique to incorporate life history information from salmon sharks and physiological parameters from other species and produced estimates of 1870, 2070, 1610 and 1762kgyear–1, depending on assumed diet. Growth modelling used salmon shark growth histories and yielded estimates of 16900 or 20800kgyear–1, depending on assumed assimilation efficiency. Of the consumption estimates, those from the mass–balance technique may be the most realistic because they incorporated salmon shark life history data and do not produce extreme values. Taken as a whole, these estimates suggest that salmon sharks have similar energetic requirements to piscivorous marine mammals.

scholarly journals Assessment of a soil with moderate level of contamination using lettuce seed assay and terrestrial isopods assimilation assay

2013 ◽  
Vol 8 (No. 2) ◽  
pp. 56-62 ◽  
Author(s):  
F.M.R. Da Silva Júnior ◽  
E.M. Garcia ◽  
R.M. Baisch ◽  
N. Mirlean ◽  
A.L. Muccillo-Baisch
Keyword(s):  
Contaminated Soils ◽  
Consumption Rate ◽  
Assimilation Efficiency ◽  
Soil Samples ◽  
Toxicity Tests ◽  
Lettuce Seed ◽  
Toxicological Screening ◽  
Terrestrial Isopods ◽  
Wet Weight ◽  
Feeding Parameters

Lettuce (Lactuca sativa) seeds play a significant role in toxicity tests of isolated chemicals, pesticides, and environmental samples. Commonly, the main variables under study are the rate of seed germination and root elongation at the end of five days of exposure. Another organisms used in environmental assessment of soil quality are terrestrial isopods. The parameter evaluated in this assay is usually mortality rate. In this study, we suggest to use the daily number of germinated seeds and wet weight of plants, and feeding measurements (consumption rate, assimilation rate, assimilation efficiency and growth rate) in woodlice (Armadillidium vulgare and Porcellio dilatatus) to detect toxicity of moderately contaminated soil samples. The lettuce seed assay proved to be more efficient in the tested conditions, however, we do not reject the use of feeding parameters in terrestrial isopods in toxicological screening of contaminated soils.

scholarly journals Seasonal Fruit Preferences for Lipids and Sugars by American Robins

The Auk ◽  
2000 ◽  
Vol 117 (3) ◽  
pp. 709-717 ◽  
Author(s):  
Christopher A. Lepczyk ◽  
K. Greg Murray ◽  
Kathy Winnett-Murray ◽  
Paul Bartell ◽  
Eric Geyer ◽  
...  
Keyword(s):  
Fast Rate ◽  
Physiological State ◽  
Assimilation Efficiency ◽  
Spatial Arrangement ◽  
Energy Gain ◽  
Nutritional Content ◽  
Turdus Migratorius ◽  
Complex Process ◽  
American Robins ◽  
Fruit Preference

AbstractFruit preference by birds is a complex process based upon the morphology and spatial arrangement of fruits and on the physiological needs and capabilities of birds. In North America, most fruits can be divided into two groups based on nutritional content: those rich in sugars relative to lipids, and those rich in lipids relative to sugars. To investigate how fruit preference may change seasonally and to determine if it is correlated with physiological state, we designed a simple laboratory experiment using American Robins (Turdus migratorius) and artificial fruits. During summer and autumn, we offered eight robins a choice between synthetic sugar-rich and lipid-rich fruits of equal caloric value and then measured food intake and assimilation efficiency for each fruit type. Overall, robins preferred sugar-rich to lipid-rich fruits during both seasons. Robins had a higher assimilation efficiency for sugars than for lipids during both seasons, although assimilation efficiency of lipids increased significantly from summer to autumn. During experiments, robins consumed significantly more sugar-rich than lipid-rich fruits in summer but not in autumn. Coupling fruit intake with assimilation efficiency indicates that in summer, robins had a higher rate of energy gain from sugars than from lipids, but by autumn the rate of energy gain from lipids increased to nearly the same level as that from sugars. Our results suggest that robins prefer sugar-rich fruits because of their simple and fast rate of digestion, enabling higher rates of energy gain, but that lipid-rich fruits become important with the onset of autumn.

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