Measurement of endogenous fecal excretion and true absorption of selenium in dairy cows

1991 ◽  
Vol 71 (1) ◽  
pp. 167-174 ◽  
Author(s):  
K. M. Koenig ◽  
J. A. Shelford ◽  
W. T. Buckley

A method combining balance techniques with an estimate of endogenous fecal selenium (Se) was evaluated as a measure of Se absorption in dairy cows. Endogenous fecal Se was estimated based on tracer enrichment in an index tissue (or fluid) that was assumed to represent enrichment of all endogenous sources of fecal Se. Two nonlactating Holstein cows fed a low-Se diet (0.035 mg Se kg−1 dry matter) were administered 4 mg Se-76, intraruminally, each day for 5 d (days 1–5). After a 10-d equilibration period, total collections of feces and urine were made at 24-h intervals for two 5-d periods (days 16–20 and days 21–25). On day 26 the animals were sacrificed and samples of all major tissues were collected. Samples were analyzed for total Se and Se stable isotope ratios. Selenium-76 enrichment was similar in tissues considered to be contributors to endogenous fecal Se, which supported the assumption that an index tissue could be used to estimate endogenous fecal excretion of Se. Endogenous fecal Se estimated from tracer enrichment in serum and liver was 22–36% of the total fecal Se excreted. True Se absorption was 10–16% of the daily Se intake. Key words: Selenium, stable isotope, tissue distribution, endogenous excretion, absorption, dairy cows

1986 ◽  
Vol 66 (4) ◽  
pp. 1009-1018 ◽  
Author(s):  
W. T. BUCKLEY ◽  
S. N. HUCKIN ◽  
L. J. FISHER ◽  
G. K. EIGENDORF

Eight Holstein cows were fed a diet supplemented with selenium at a subtoxic level (2.37 mg kg−1 dry matter), or the same diet without selenium supplementation (0.31 mg kg−1 dry matter), for 276 d of lactation. Copper-65, a stable isotope, was administered intravenously after 14 d of adaptation to the diets, and samples of milk, blood and liver were obtained at intervals throughout the trial. The effect of selenium supplementation on copper metabolism of the cows was evaluated by determining concentrations of copper in plasma, milk and liver, by determining the activities of ferroxidase in plasma and superoxide dismutase in erythrocytes and by determining the pattern of dilution of the copper-65 tracer in plasma, milk and liver. No effect of selenium supplementation on any of the parameters of copper metabolism was observed. It was concluded that an interaction between copper and selenium did not occur under the conditions imposed in this study. Key words: Copper, selenium, interaction, dairy cows, copper stable isotope


Author(s):  
Sosuke Otani ◽  
Sosuke Otani ◽  
Akira Umehara ◽  
Akira Umehara ◽  
Haruka Miyagawa ◽  
...  

Fish yields of Ruditapes philippinarum have been decreased and the resources have not yet recovered. It needs to clarify food sources of R. philippinarum, and relationship between primary and secondary production of it. The purpose on this study is to reveal transfer efficiency from primary producers to R. philippinarum and food sources of R. philippinarum. The field investigation was carried out to quantify biomass of R. philippinarum and primary producers on intertidal sand flat at Zigozen beach in Hiroshima Bay, Japan. In particular, photosynthetic rates of primary producers such as Zostera marina, Ulva sp. and microphytobenthos were determined in laboratory experiments. The carbon and nitrogen stable isotope ratios for R. philippinarum and 8 potential food sources (microphytobenthos, MPOM etc) growing in the tidal flat were also measured. In summer 2015, the primary productions of Z. marina, Ulva sp. and microphytobenthos were estimated to be 70.4 kgC/day, 43.4 kgC/day and 2.2 kgC/day, respectively. Secondary production of R. philippinarum was 0.4 kgC/day. Contribution of microphytobenthos to R. philippinarum as food source was 56-76% on the basis of those carbon and nitrogen stable isotope ratios. Transfer efficiency from microphytobenthos to R. philippinarum was estimated to be 10-14%. It was suggested that microphytobenthos might sustain the high secondary production of R. philippinarum, though the primary production of microphytobenthos was about 1/10 compared to other algae.


ACS Omega ◽  
2021 ◽  
Author(s):  
Purna K. Khatri ◽  
Roberto Larcher ◽  
Federica Camin ◽  
Luca Ziller ◽  
Agostino Tonon ◽  
...  

Metabolites ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 186
Author(s):  
Luana Bontempo ◽  
Daniela Bertoldi ◽  
Pietro Franceschi ◽  
Fabio Rossi ◽  
Roberto Larcher

Umbrian tobacco of the Virginia Bright variety is one of the most appreciated tobaccos in Europe, and one characterized by an excellent yield. In recent years, the Umbria region and local producers have invested in introducing novel practices (for production and processing) focused on environmental, social, and economic sustainability. Due to this, tobacco from Umbria is a leading commodity in the global tobacco industry, and it claims a high economic value. The aim of this study is then to assess if elemental and isotopic compositions can be used to protect the quality and geographical traceability of this particular tobacco. For the first time the characteristic value ranges of the stable isotope ratios of the bio-elements as a whole (δ2H, δ13C, δ15N, δ18O, and δ34S) and of the concentration of 56 macro- and micro-elements are now available, determined in Virginia Bright tobacco produced in two different areas of Italy (Umbria and Veneto), and from other worldwide geographical regions. The ranges of variability of elements and stable isotope ratios had slightly different results, according to the three geographical origins considered. In particular, Umbria samples presented significantly lower content of metals potentially dangerous for human health. The results of this first exploratory work highlight the possibility of characterizing tobacco from Umbria, and suggest widening the scope of the survey throughout Italy and foreign regions, in order to be used to describe the geographical origin of tobacco in general and verify the origin of the products on the market.


2015 ◽  
Vol 30 (1) ◽  
pp. 170-174 ◽  
Author(s):  
L. Bontempo ◽  
F. Camin ◽  
L. Ziller ◽  
L. Biondi ◽  
M. G. D'Urso ◽  
...  

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