Studies in vitamin A. 7. Carotene metabolism in herbivores

Goodwin, T. W.; Gregory, R. A.

doi:10.1042/bj0430505

Cited by 44 publications

(5 citation statements)

References 7 publications

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“…Experiments were undertaken therefore, (1) to attempt, using sections of the small intestine of sheep, a repetition of the surviving tissue experiments by which Wiese, Mehl, and Deuel (1947) had so elegantly established the site of conversion in the rat, and, if positive results were obtained, (2) to investigate the mode of transport of the vitamin A from the intestine to the liver, and (3) to determine whether conversion occurred throughout the length of the small intestine or was restricted to certain regions. Since this work was commenced, Thompson, Ganguly, and Kon (1949) have extended previous observations with rats and have shown the site of conversion to be the wall of the intestine in pigs also, while similar findings have been reported for sheep, goats, and rabbits (Goodwin and Gregory 1948), and recently for calves (Stallcup and Herman 1950). Using somewhat different methods, the present investigation has, however, provided further evidence in support of the findings of these later workers and the results are submitted in confirmation of their conclusions regarding the site of conversion in cattle and sheep.…”

supporting

confidence: 56%

“…Although, in a preliminary experiment, the vitamin A level in the portal blood was found to be markedly higher than in the systemic blood, it is doubtful whether reliance can be placed on this observation, since, as pointed out by Goodwin and Gregory ( 1948), absorption processes in general are retarded by anaesthesia and trauma, and these experiments were not proceeded with.…”

Section: (B) Transport Of Vitamin a From The Intestines To The Livermentioning

confidence: 99%

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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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supporting

confidence: 56%

Section: (B) Transport Of Vitamin a From The Intestines To The Livermentioning

confidence: 99%

The Conversion of Carotene to Vitamin a in Sheep and Cattle

Wa¹

1951

Aust. Jnl. Of Bio. Sci.

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“…It must be noted that many workers could not detect such destructive action of the intestinal contents in vitro. Virtanen & Kreula (1941) and Goodwin & Gregory (1948) incubated faeces with carotene and could not detect any loss. Sexton, Mehl & Deuel (1946) reported carotene to be stable also when incubated in the excised gastro-intestinal tract.…”

Section: Discussionmentioning

confidence: 94%

The effect of different plant sources on the utilization of carotene by chickens

Ascarelli

Bondi

1957

J. Agric. Sci.

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The possibility was examined of supplying vitamin A to chickens from the first days of life as carotene in green plants. Growth experiments were carried out with chickens till the age of 8 weeks. Different kinds of forage (horse-beans, Berseem clover, green oats, sweet potato leaves, cow-peas, corn-leaves) were given in quantities calculated to supply 300 μg. carotene per 100 g. feed; control groups received fish-liver oil, given at the level of 500 i.u. per 100 g. feed. Weight gains and extent of vitamin A storage in liver served as an indication of the utilization of carotene from different sources. The utilization of carotene from all the plants examined was sufficient to support normal growth, only in the groups receiving clover was growth found to be somewhat slower. Remarkable differences were found in the extent of liver storage, and that was taken as an indication of differences in activity of the carotene from the different sources.Attempts to determine the reasons for these differences in liver storage capacity of the carotene from the various plants did not reveal the presence of any plant components enhancing or depressing vitamin A storage.Similarly, no correlation could be found between digestibility coefficients of carotene in the different plants and liver vitamin A storage. This correlation seemed likely in sweet potato leaves only, the rather low digestibility coefficient found in these leaves may account, at least partially, for the low activity of this plant.The stereoisomeric composition of the β-carotene of the different plants and the xanthophyll/carotene ratio are very similar in all plants tested and cannot account for differences in carotene activity of the plants studied.The results of this work show that it is possible to satisfy the requirements of chicks for vitamin A from the first days of life by supplying certain forage plants. In practice, because of the variability of the carotene content in such plants, care has to be taken when estimating the amounts to be given. Green plants should be given to chickens freely or at least in liberal amounts.

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“…each) were examined for carotene, retinene and vitamin A according to the method in general use in this laboratory (see, e.g. Goodwin & Gregory, 1948).…”

Section: (Received 4 March 1949)mentioning

confidence: 99%