The absorption of vitamin A in ruminants and rats

Eden, E.; Sellers, K.C.

doi:10.1042/bj0440264

Cited by 23 publications

(4 citation statements)

References 3 publications

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“…From these results it may be concluded that in sheep the wall of the intestine is a site of conversion of carotene to vitamin A. Eden and Sellers (1948) found the lymphatic route to be the main one by which the vitamin A absorbed was transported to the liver following oral administration to bullocks of emulsified halibut liver oil. From the vitamin A levels found in the intestinal and nonintestinal lymph of sheep in the present investigation, it is apparent that part at least of the vitamin A derived from the conversion of carotene in the wall of the intestine is also transported via the lymphatic route.…”

Section: Resultsmentioning

confidence: 77%

The Conversion of Carotene to Vitamin a in Sheep and Cattle

Wa¹

1951

Aust. Jnl. Of Bio. Sci.

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SummaryIt has been established that the conversion of carotene to vitamin A in the sheep occurs in the wall of the intestine. This conclusion is based on surviving tissue experiments in which sections of intestine have been incubated with carotene and the product conclusively identified as vitamin A by colorimetric and spectrophotometric methods. It is further supported by the high vitamin A levels in intestinal as compared with non-intestinal lymph, and similar observations with cattle suggest the intestine as the site of conversion in this species also.

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Section: Resultsmentioning

confidence: 77%

The Conversion of Carotene to Vitamin a in Sheep and Cattle

Wa¹

1951

Aust. Jnl. Of Bio. Sci.

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“…(15,16)). A single dose of vitamin A would therefore cause a marked transitory rise in blood plasma vitamin A ester, and the results presented in Table 1 show that a similar rise occurred in the level of vitamin A ester in the milk fat reflecting qualitatively but not quantitatively the magnitude of the dose.…”

Section: (1) Effect Of Carotene-free Dietmentioning

confidence: 96%

658. Factors influencing the vitamin content of milk fat: IV. The source of milk fat vitamin A and carotene

McGillivray

1957

Journal of Dairy Research

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With 2 Figures)'During the course of investigations into factors affecting the vitamin content of New Zealand milk fats(i, 2,3) the need for further information about the source of the milk fat vitamin A and carotene became apparent. Experiments were therefore carried out to investigate the relationship between the levels of carotene and vitamin A ester in the blood plasma and milk fat, and to assess the relative contributions of vitamin A of hepatic origin (through the blood plasma vitamin A alcohol) and vitamin A of immediate dietary origin (through the blood plasma vitamin A ester) to the vitamin A content of the milk fat. It is well recognized that for the production of milk fat of high vitamin A potency, cows are more dependent on a daily carotene or vitamin A intake than on liver reserves of vitamin A (e.g. (4)). For other species, relationships between dietary and milk fat vitamin A have been studied (e.g. (5)) and aspects of the problem have recently been investigated in cows by Chanda and co-workers(6,7,8). It seemed, however, that further information obtained under New Zealand conditions would enable a more precise interpretation of the seasonal variations already reported (3,9,10,11) in the levels of vitamin A and carotenoids in the milk fat and blood plasma of pasture-fed cows in this country. EXPERIMENTALThe cows used were predominantly Jersey from the herds of The Dairy Research Institute (N.Z.) and Massey Agricultural College. Unless otherwise stated, all cows were milked normally twice daily, milk samples being collected at the evening milking.In the first experiment, carried out in December, two cows, which had been fed normally on pasture, were brought indoors and fed, for 11 days, a carotene-free diet consisting of linseed meal, crushed oats and bran in equal quantities and straw ad lib. as roughage. At the end of this period they were returned to pasture. Milk and blood samples were taken throughout the experiment.In the second experiment, carried out in August, the effect on the milk fat levels of a single dose of vitamin A was investigated. The cows were on pasture throughout the experiment and were dosed orally with varying levels of vitamin A.* Milk samples were collected at intervals and, in the case of one cow, simultaneous milk and blood samples were taken at frequent intervals following the dose of vitamin A. * The vitamin A was administered as an emulsion supplied by Nicholas Products Ltd., Wellington, and containing approximately 8 mg. vitamin A per gram.

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“…Optimization of the structure of the diet, normalization of nitrogen and carbohydrate-fat metabolism, providing animals with minerals and vitamins can significantly increase the absorption of carotene. At the same time, the absorption is significantly influenced by the level of vitamin A reserves in the body, genetically determined activity of the hormonal system and other factors that determine the nature and intensity of metabolic processes (Eden & Sellers, 1949;Ganguly, & Sastry, 1985;Shete & Quadro, 2013).…”

Section: Causes and Pathogenesis Of A-vitamin Infertilitymentioning

confidence: 99%

Effect of abiotic factors on sulfidogenic activity of bacteria Desulfuromonas sp.

Сhaіka

Peretyatko

2020

Regul. Mech. Biosyst.

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Sulfur-reducing bacteria are promising agents for the development of new methods of wastewater treatment with the removal of ions of heavy metals and organic compounds. Study of the effect of various environmental factors on the growth and sulfidogenic activity of sulfur-reducing bacteria allows one to investigate the adaptability of these microorganisms to stress factors. The paper deals with the effect of рН, different concentrations of elemental sulfur, hydrogen sulfide and presence of various electron acceptors on the growth and sulfidogenic activity of bacteria Desulfuromonas sp. YSDS-3. The calculation of C/S ratio for sulfur-reducing bacteria Desulfuromonas sp. YSDS-3 was made, with the comparison with similar parameters of sulfate-reducing bacteria. In the medium with elemental sulfur, concentration of hydrogen sulfide increased with the concentration of elemental sulfur. Bacteria Desulfuromonas sp. YSDS-3 accumulated their biomass in the most effective way at the concentration of elemental sulfur of 10–100 mM. In the medium with polysulfide form of sulfur at the neutral pH, bacteria produced hydrogen sulfide and accumulated biomass the best. Hydrogen sulfide at the concentration of 3 mM did not inhibit the bacterial growth, but further increase in the hydrogen sulfide concentration inhibited the growth of bacteria. The bacteria did not grow at the hydrogen sulfide concentration of 25 mM and above. As the concentration of elemental sulfur and cell density increases, sulfidogenic activity of the bacteria grows. Presence of two electron acceptors (S and K2Cr2O7, S and MnO2, S and Fe (III)) did not affect the accumulation of biomass of the bacteria Desulfuromonas sp. YSDS-3. However, under such conditions the bacteria accumulated 1.5–2.5 times less hydrogen sulfide than in the test medium. After 12–24 h of cultivation, different concentrations of elemental sulfur had a significant effect on the sulfidogenic activity. However, during 3–16 days of cultivation, the percentage of effect of elemental sulfur concentration decreased to 31%, while the percentage of effect of cell density increased threefold. Presence in the medium of the electron acceptors (Cr (VI), MnO2, Fe (III)) alternative to elemental sulfur led to a significant decrease in the content of hydrogen sulfide produced by sulfur-reducing bacteria.

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The absorption of vitamin A in ruminants and rats

Cited by 23 publications

References 3 publications

The Conversion of Carotene to Vitamin a in Sheep and Cattle

The Conversion of Carotene to Vitamin a in Sheep and Cattle

658. Factors influencing the vitamin content of milk fat: IV. The source of milk fat vitamin A and carotene

Effect of abiotic factors on sulfidogenic activity of bacteria Desulfuromonas sp.

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