Synthesis of Vitamins by Micro-organisms of the Alimentary Tract

Kon, S. K.

doi:10.1017/s0029665145000119

Cited by 21 publications

(5 citation statements)

References 117 publications

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“…In this case, there is a decrease specifically in the requirement for a single amino acid. Similar effects have been observed in rats fed on diets deficient in either methionine (26) or isoleucine (37). Under conditions of ad libitum feeding the amino acid requirements of rats, reported as a percentage of the diet, may be affected by the type of dietary carbohydrate.…”

Section: Growth Of Animals Receiving Purified Dietssupporting

confidence: 64%

Dietary Carbohydrates, A Review of the Effects of Different Carbohydrates on Vitamin and Amino Acid Requirements

Harper¹,

Elvehjem²

1957

J. Agric. Food Chem.

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Section: Growth Of Animals Receiving Purified Dietssupporting

confidence: 64%

Dietary Carbohydrates, A Review of the Effects of Different Carbohydrates on Vitamin and Amino Acid Requirements

Harper¹,

Elvehjem²

1957

J. Agric. Food Chem.

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“…The suggestion that it is a process in the digestion of cellulose comparable to rumination has yet to be confirmed. Olsen & Madsen (1944) showed that the composition of hard faeces differed very little between rabbits which had been prevented from reingesting and those which had not ; Eden (1940 b) demonstrated the similarity of the soft pellets to the caecal contents and suggested that reingestion made the bacterial protein from the caecum available for digestion ; Kon (1944) pointed out the possibility of the animal making use in this way of the vitamin B synthesized by.the intestinal bacteria ; and Scheunert & Zimmermann (1951) found four times more vitamin B 1 in the soft than in the hard faeces.…”

Section: Observat~ons On Live Rabbitsmentioning

confidence: 99%

Reingestion in the Wild Rabbit, Oryctolagus cuniculus (L.)

Watson¹

1954

Proceedings of the Zoological Society of London

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Summary. An attempt was made to determine the times of day at different seasons when wild rabbits in Hawke's Bay, New Zealand, were reingesting soft faecal pellets. The faecal material eaten by the rabbit varies from distinct mueus‐coated pellets to a semi‐liquid material in which the individual pellets are almost, or completely, unformed. These last are usually produced at the start of the reingestion period. Pellets can be recognized in the stomach up to nine hours after they have been eaten, so that the time when reingestion is occurring must be determined from the presence of the soft faeces in the rectum. The majority of rabbits are reingesting from 08.00 to 12.00 hrs. (N.Z. Standard Time) but there is considerable individual variation so that some may start three hours earlier than this and some continue up to three hours longer. There is no apparent seasonal variation in the peak time of this activity but there are indications that the fist animals may start about sunrise. At the beginning of the reingestion period the soft pellets are produced intermittently in short periods alternating with the production of hard pellets. Young rabbits begin reingesting as soon as they start eating grass and before they are fully weaned. The quantity of food in the stomach varies with the time of day and indicates that the main feeding time is in the early morning before the reingestion time. The main times of reingestion appear to be the same in New Zealand and in England, yet there are individual variations and differences in detail which suggest that the behaviour is easily modified by the environment.

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“…Kon, 1945) suggests that the establishment and maintenance of refection is dependent on a flourishing caecal flora. Some measure of the starch-splitting activity of this flora can be obtained from the pH of the caecal contents of rats receiving the various diets.…”

Section: Volmentioning

confidence: 99%

“…The existence of refection has been confirmed by later workers (cf. review by Kon, 1945), but the full mechanism of establishing and maintaining the refected state has not yet been satisfactorily explained.It is now known that the intestinal flora of rats, and indeed of most animals, synthesizes all the well-characterized vitamins of the B complex. The contribution of this microbial synthesis to the vitamin requirements of rats on normal diets is relatively small, but refected rats are evidently able to derive the whole of their B vitamins from the products of such synthesis.…”

mentioning

confidence: 99%

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The Effect of Sulphonamides and of Cooking or Grinding the Diet on the Excretion of Vitamins of the B Complex by the Refected Rat

et al. 1953

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Refection in rats was first recognized by Fridericia (1926), who described the condition as 'a transmissible change in the intestinal content, enabling rats to grow and thrive without B-vitamin in the food'. The existence of refection has been confirmed by later workers (cf. review by Kon, 1945), but the full mechanism of establishing and maintaining the refected state has not yet been satisfactorily explained.It is now known that the intestinal flora of rats, and indeed of most animals, synthesizes all the well-characterized vitamins of the B complex. The contribution of this microbial synthesis to the vitamin requirements of rats on normal diets is relatively small, but refected rats are evidently able to derive the whole of their B vitamins from the products of such synthesis. Thus either the total amount of vitamins synthesized must be greater in the refected than in the normal rat or the efficiency of utilization must be higher or, more probably, both. Kon, Kon & Mattick (1938) suggested that the presence of undigested starch in the caecum of the refected rat, along with the requisite starch-splitting enzymes led to a vigorous fermentation and a resulting acid pH that created conditions favourable for both vitamin synthesis and absorption.During recent years the effect of sulphonamides on the synthetic activities of intestinal micro-organisms has been extensively studied, and muchvaluable information 1946), who found that sulphonamides depressed the growth rate of the rats and their faecal excretion of both vitamins. Untreated refected rats excreted no measurable amounts of thiamine in the urine, whereas their urinary excretion of riboflavin was comparable with that of stock rats. Administration of sulphonamides caused a marked depression in this excretion. It was concluded from these experiments that thiamine is probably the limiting factor in refection, and that the bacterial flora of the refected rat synthesizes riboflavin in excess of requirements. In further work a more detailed study was made of the excretion by the refected rat of several members of the vitamin B complex and of the effect thereon of sulphonamides and of cooking or grinding the diet. EXPERIMENTAL GeneralThe experiments were done with two batches of rats. The first series of collections was made from the first of these batches in 1947, and the second series of collections from the second batch in 1949. The urine, faeces and caecal contents of the groups of rats were analysed for seven vitamins of the B complex: thiamine, riboflavin, nicotinic acid (and in urine N-methylnicotinamide), pantothenic acid, biotin, folic acid and vitamin B,. After the second series of collections the livers of the rats were also analysed for these vitamins. DietsThe first batch of rats received one of the following four diets: ( that the ability of starch to support refection would be destroyed on milling in the same way as on gelatinizing the starch by cooking. Management of ratsMale and female rats from the stock colony were placed at weaning on the refe...

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Synthesis of Vitamins by Micro-organisms of the Alimentary Tract

Cited by 21 publications

References 117 publications

Dietary Carbohydrates, A Review of the Effects of Different Carbohydrates on Vitamin and Amino Acid Requirements

Dietary Carbohydrates, A Review of the Effects of Different Carbohydrates on Vitamin and Amino Acid Requirements

Reingestion in the Wild Rabbit, Oryctolagus cuniculus (L.)

The Effect of Sulphonamides and of Cooking or Grinding the Diet on the Excretion of Vitamins of the B Complex by the Refected Rat

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