Riboflavin Requirement Research Articles

EVALUATION OF ERYTHROCYTE RIBOFLAVIN IN LOW BIRTHWEIGHT INFANTS: RELATIONSHIP TO MODE OF NUTRITION

Riboflavin requirements for total parenteral nutrition (TPN) regimens have not been adequately determined. We investigated the riboflavin status of low-birthweight infants maintained by TPN formulation which provided 4 mg/day of riboflavin to each infant compared to that of infants fed orally on formula containing 1.0 to 5.0 mg riboflavin/liter.15 newborn infants (birthweight 570-2350 grams) had baseline blood samples drawn prior to TPN or formula feeding. The patients had second blood samples drawn after they had been fed either orally (n=7) or by TPN (n=8) for at least 7 days.None of the 15 infants showed abnormal riboflavin status and the range established for these low-birthweight infants (AC 0.86-1.19) corresponds to that established for healthy full-term newborns(0.9-1.2). (Proc. Soc. Exp. Biol. Med 143:326, 1973).From this pilot study, it appears that 4 mg/day of riboflavin provided to low-birthweight infants in a TPN solution maintains riboflavin status during the time period studied (7 days).

Comments on methods for estimating riboflavin requirements

Comments on methods for estimating riboflavin requirements

Sensitivity of hepatic D-amino acid oxidase and glutathione reductase to the riboflavin status of the rainbow trout ( Salmo gairdneri)

Two hepatic enzymes, D-amino acid oxidase (DAAO) and glutathione reductase (GR), were assessed for their potential to determine the riboflavin requirement of rainbow trout ( Salmo gairdneri). Both enzymes exhibit sufficient activity to permit precise quantification in fry, fingerlings and young juveniles. Hepatic GR activity was not affected, even in severely riboflavin-deficient fish. DAAO activity was depressed by riboflavin deficiency, and appeared to provide a more sensitive indicator of incipient vitamin insufficiency than either tissue flavin storage or grossly observable symptoms. DAAO activity was not affected by reduced feed intake as indicated by examination of pair-fed controls. The results suggest that liver maximal DAAO activity may prove useful for determining the riboflavin requirement of young rainbow trout.

Effects of exercise on riboflavin requirements of young women

The riboflavin requirement of young women during periods of sedentary living and exercise was determined during a 12-wk metabolic study. The study was divided into a 6-wk no exercise period followed by a 6-wk exercise period in which subjects jogged around a track for 20 to 50 min/day. Twelve subjects, aged 19 to 27 yr, were fed a basic diet containing 0.6 mg riboflavin/1000 kcal of intake. Riboflavin intake was increased by 0.2 mg/1000 kcal increments by provision of riboflavin in a glucose polymer mixture. Linear regression analysis was used to estimate the riboflavin intake required for an erythrocyte glutathione reductase activity coefficient of 1.25 during both the no exercise and exercise periods. Individual riboflavin requirements ranged from 0.62 to 1.21 mg/1000 kcal before exercise and 0.63 to 1.4 mg/1000 kcal during the exercise periods. Riboflavin requirement could not be related to the kilocalorie intake or lean body mass of the subjects. It is concluded that healthy young women require more riboflavin to achieve biochemical normality than the 1980 Recommended Dietary Allowances and that exercise increases riboflavin requirements.

Elevated Riboflavin Requirement for Postphotoinductive Events in Sporulation of a Trichoderma Auxotroph

A riboflavin auxotroph of Trichoderma required more riboflavin for blue-light-induced conidiation than for growth. Colonies transferred after illumination from 0.2 micromolar (limiting conidiation, not growth) to 3.5 micromolar riboflavin (nonlimiting), responded the same as those grown at 3.5 micromolar. The additional riboflavin is therefore not required as a photoreceptor. The data do not rule out the hypothesis that cryptochrome(s) is/are flavin(s).

Growth and Riboflavin Status of Rats Fed Different Levels of Protein and Riboflavin

The relationship between riboflavin and protein utilization was studied in 5-week-old male Sprague-Dawley rats, by using a factorial design with three levels of riboflavin (8, 16 and 24 µg per rat per day) and protein (1.0, 1.6 and 2.2 g casein per rat per day) in a 9-week experiment. With the lowest level of casein, protein intake was growth limiting, and the level of riboflavin intake had no effect on either weight gain or liver nitrogen retention. With the two higher levels of casein, both weight gain and liver nitrogen retention increased with riboflavin intake, but 24 µg riboflavin per day was inadequate for maximal utilization of nitrogen from 2.2 g casein. Neither protein nor riboflavin intake affected the concentration of liver nitrogen per gram of fresh tissue. Increasing the protein intake from 1.0 to 1.6 g increased riboflavin retention in the liver, but additional protein had no further effect. Liver and muscle (gastrocnemius) riboflavin concentrations, as micrograms per gram wet tissue, increased with riboflavin intake. At the two higher intakes of riboflavin, tissue riboflavin levels decreased and the erythrocyte glutathione reductase activity coefficients (EGR-AC) increased with protein intake. These findings are consistent with the view that the effect of protein on riboflavin requirement is related to the rate of growth and not to protein intake, per se.riboflavin-protein interdependence riboflavin status erythrocyte glutathione reductase activity coefficient

Riboflavin requirements of lactating Gambian women: a controlled supplementation trial

As part of a study to determine the minimum allowance of riboflavin which is adequate for lactating women in a rural African environment, 60 subjects living in two Gambian villages were given either 2 mg riboflavin or a placebo daily on a double-blind basis for 12 wk. Their riboflavin intake from dietary sources was about 0.5 mg/day. In the supplemented group, the mean activation coefficient (AC) of erythrocyte glutathione reductase fell from 1.62 to 1.19 within 3 wk, and 90% had mean AC's below 1.3 throughout supplementation, whereas the placebo group maintained mean AC's between 1.6 and 1.9. Clinical signs associated with riboflavin deficiency improved more rapidly in the supplemented group; their breast milk riboflavin levels increased, and their infants' AC's were reduced, compared with those of the placebo group. After withdrawal of the supplement, the maternal and infants' AC's rose toward those of the placebo group. Thus a total riboflavin intake of about 2.5 mg/day during lactation is sufficient to maintain normal biochemical status in most Gambian women.

Factors affecting riboflavin requirements of oral contraceptive users and nonusers

Riboflavin depletion has been identified in women on oral contraceptives (OC) but change in riboflavin nutriture has not been consistently demonstrated in all OC user groups studied. Discrepant findings in reports have been attributed to differences of pill formulation or riboflavin intake. Aims of this study were to compare the riboflavin requirements of healthy OC users and nonusers on diets prepared in a metabolic unit. A single daily menu and meal pattern was used. The basic diet providing riboflavin at a level of 0.6 mg/1000 kcal was used in the period of acclimation and period 1. In periods 2 and 3, the riboflavin content of the diet was increased to 0.8 and 1.0 mg/1000 kcal, respectively. The riboflavin status of subjects was monitored by erythrocyte glutathione reductase assay and urinary riboflavin excretion. Eight women on OC and 10 nonusers participated. Erythrocyte glutathione reductase assay values and urinary riboflavin excretion showed intersubject and interperiod differences but no significant group differences (OC versus non-OC) in erythrocyte glutathione reductase values or in urinary riboflavin per g creatinine. It was concluded that when dietary intake is controlled, OC do not significantly influence riboflavin status. Riboflavin needs were related to energy requirements of the subjects.

コイおよびニジマスにおけるリボフラビンの要求

The requirements and deficiency symptoms of riboflavin and the availability of riboflavin retrabutyrate were investigate wity the carp, Cyprinus carpio, and the rainbow trout, Salmo gairdneri. The intestinal homoginate of the rainbow trout was found to hydrolyze riboflavin tetrabutyrate and to liberate riboflavin from the ester. The feeding experiwents with these fish species also revealed that the riboflavin-ester was available like free ribofalvin. The fish fed diets containing riboflavin tetrabutyrate accumulated riboflavin in the liver or hepatopancreas. The anorexia, poor growth, and high mortality rate were observed in both fish species as the general deficiency symptoms of riboflavin. Together with these symptoms, hemorrhage of the skin and the fins in the carp and lesion of the fins and cataract in the rainbow trout were characteristic signs of the deficiercy. The dietary riboflavin levels required to provide the maximum storage of the vitamin in the hepatic tissue were 0.7 mg in the carp and 0.6mg in in the rainbow trout/100g dry tiet, respectively. The riboflavin requirements of these fish species were not influenced by the dietary lipid levels.

Riboflavin Requirement of Channel Catfish Fingerlings

Channel catfish fingerlings were fed purified diets containing five levels (0, 20, 40, 80, and 120 mg/kg) and six levels (0, 3, 8, 20, 40, and 80 mg/kg) of riboflavin in separate 20 and 12 week feeding studies. The dietary riboflavin level required to provide maximal growth in channel catfish fingerlings was found to be approximately 9 mg/kg of diet. All fish fed unsupplemented diets (riboflavin content less than 0.1 mg/kg diet) demonstrated a short body dwarfism which was the result of arrested longitudinal growth of the vertebrae. This abnormality did not occur in groups fed 3 mg/kg or higher levels of riboflavin. No histological abnormalities were recognized in the liver, kidney, lateral muscle, gastrointestinal tract, gills, or bones of deficient fish.

Mineral and vitamin supplementation of diets for growing pigs. 1. Wheat-based diets and the effect of preventing cross-coprophagy on the response to supplementation

Two factorial experiments examined the effects of mineral and or vitamin supplementation on the performance of 64 growing pigs. The wheat-based diets contained either meat-and-bone meal (with some fish meal up to 32 kg liveweight) or solvent-extracted soybean meal (SBM). A basal supplement of vitamins A and D2 was added to all diets. The pigs were individually fed at restricted intakes between 18 and 73 kg liveweight and housed as mixed treatment groups. In a third factorial experiment, 32 growing pigs were restrictively fed a wheat/SBM diet from 20 kg liveweight to 75 kg or for 20 weeks. The pigs were individually housed to prevent cross-transfer of vitamins from supplemented to unsupplemented pigs by way of the faeces (cross-coprophagy). Mineral supplementation of the wheat/animal protein diet (experiment 1) did not affect pig performance, but improved the growth rate and feed conversion ratio of pigs fed the SBM diet (experiment 2) by 45 and 32 per cent respectively. Omitting the mineral supplement from the SBM diet caused loss of appetite, soft bones, joint and foot abnormalities and lameness in many pigs; 5 out of 16 pigs did not reach slaughter weight. Gilts fed the SBM diet were less tolerant of mineral deficiencies than barrows. They also stored less calcium in their bones when minerals were added to the diet. There was no response to vitamin supplementation even though both diets, but especially the SBM diet, were apparently deficient in a number of vitamins. The SBM diet provided 76, 83 and 53 per cent respectively of the pigs' estimated requirements for riboflavin, pantothenic acid and vitamin B12. In experiment 3 the SBM diet supplied 64, 80 and 28 per cent of the pigs' riboflavin, pantothenic acid and vitamin B12 requirements. As in experiment 2, there was no response to vitamin supplementation. Cross-coprophagy was thus most unlikely to have caused the lack of response to vitamin supplementation in the group-housed pigs of experiment 2. Mineral supplementation improved growth rate by 108 per cent and feed conversion ratio by 40 per cent.

Riboflavin Requirement of Starting Chickens in a Tropical Environment

Growth rate of broiler chicks tends to be lower in the tropics than in the temperate zone. Results show that up to 17% of dietary riboflavin is destroyed within 24 hours of exposure of the feed to light hence the level of 3.6 mg. of vitamin B2 recommended does not meet the requirement for growth of broilers. Growth study as well as accumulation of riboflavin in meat and organs of the birds showed that increasing levels of dietary riboflavin increases its deposition in meat and organs of the birds. Optimum growth of birds and storage of riboflavin in the body is attained in the tropical environment when 5.1 mg. of the vitamin is added per kg. of practical ration.

Regulation of 6-hydroxy-2,4,5-triaminopyramidine synthesis by riboflavin and iron in riboflavin-deficient mutants of Pichia guilliermondii yeast

The effect of riboflavin and iron on 6-hydroxy-2,4,5-triaminopyrimidine synthesis rate was investigated in the cultures of the yeast Pichia guilliermondii (rib 2 mutants) with the blocked second reaction of flavinogenesis. It was shown that riboflavin inhibited the 6-hydroxy-2,4,5-triaminopyrimidine synthesis rate in iron-rich and iron-deficient cells of mutants with low riboflavin requirements. Cycloheximide did not prevent the stimulation of 6-hydroxy-2,4,5-triaminopyrimidine synthesis caused by riboflavin starvation. 7-methyl-8-trifluoromethyl-10-(1′- d-ribityl)isoalloxazine strongly inhibited the 6-hydroxy-2,4,5-triaminopyrimidine synthesis, while 7-mithyl-8-trifluoromethyl-10-(β-hydroxyethyl) izoalloxazine and galactoflavin exerted only a slight effect on this process. The 6-hydroxy-2,4,5-triaminopyrimidine synthesis rate in iron-deficient cells was significantly higher than in iron-rich cells. The 2,2′-dipyridyl treatment of iron-rich cells caused the stimulation of 6-hydroxy-2,4,5-triaminopyrimidine synthesis and cycloheximide abolished this effect. The results suggest that the activity of the first enzyme of flavinogenesis (guanylic cyclohydrolase) is under the control of feedback inhibition by flavins and the biosynthesis of this enzyme is regulated by iron.

Vitamin requirements of larvae of Sitophilus oryzae

Improvements were made in the meridic larval diet for Sitophilus oryzae by replacing the minerals and vitamins supplied by dietary brewer's yeast and wheat germ with mineral and vitamin mixtures. The effects of different concentrations of individual vitamins were studied with the improved diet containing 20% casein. In later tests the dietary casein was replaced with a mixture of 15 amino acids. The results indicated that these larvae, which contain an associated bacteria-like micro-organism, required thiamine, nicotinic acid, pyridoxine, folic acid, and biotin in the diet. No requirement for riboflavin or pantothenic acid could be demonstrated on either the 20% casein diet or the amino acid diet possibly due to contamination of the cornstarch with these two vitamins. In addition, the larvae did not require choline or inositol for the growth of one larval generation.The asymbiotic larvae of S. granarius failed to develop on the improved casein diet indirectly implicating the symbiotes in a nutritional rôle; however, the symbiotes present in S. oryzae apparently do not provide B vitamins. Larvae of S. oryzae failed to develop when the concentration of casein was reduced to 10% while growth was maintained with a 10% concentration of the amino acid mixture. Casein is not an optimal source of amino acids for this species.

Studies on a Possible Interaction Between Riboflavin and Vitamin B12 as it Affects Hatchability of the Hen’s Egg

Experiments were conducted using Single Comb White Leghorn chickens to investigate a possible interaction between the requirements for riboflavin and vitamin B12 for hatchability and to determine how important such an interaction might be in altering the requirements for one or both of these vitamins. The vitamin B12 requirement for optimum hatchability was found to be 3.45–3.60 μg./kg. of diet, and the requirement for dietary riboflavin, approximately 2.75 mg./kg. of diet. Dietary riboflavin at deficient or practical levels of feeding was found not to affect the vitamin B12 concentration in egg yolk, or the vitamin B12 requirement for optimum hatchability. Although a slight sparing effect of vitamin B12 upon the riboflavin requirement was suggested by the present studies, the effect was not statistically significant (p < .05). High levels of dietary vitamin B12 exerted a striking negative effect on riboflavin concentrations in egg yolk (p < .05). Egg production and food consumption were not affected by dietary riboflavin levels ranging from 1.61 to 5.51 mg./kg. of diet or vitamin B12 ranging from 1.0 to 11.0 μg./kg. of diet. However, optimum egg size was achieved only when the highest level of vitamin B12 was fed.

The Structure and Acetylene-reducing Activity of Root Nodules Formed by a Riboflavin-requiring Mutant of Rhizobium trifolii

SUMMARY: Root nodules formed by a riboflavin-requiring auxotroph of Rhizobium trifolii (TI/D-hisr-15) on red clover (Trifolium pratense L.) seedlings grown with or without added riboflavin, showed changes in structure or acetylene-reducing activity when compared with effective nodules produced by the parent strain (TI). Additional riboflavin was essential for the conversion of vegetative bacteria of the mutant strain into functional, N2-fixing bacteroids within the nodules. If riboflavin was not added to the plants, a large proportion of the rhizobia in the host cells failed to develop, and the nodules were almost ineffective, reducing acetylene at a very low rate. When riboflavin was added to the plant growth medium, even as late as 8 days after inoculation, most mutant rhizobia survived and continued to develop into normal bacteroids. This requirement for riboflavin was most critical 1 to 3 days after the appearance of the nodules (about 7 to 9 days after inoculation). If the auxotroph was sustained through this period with added riboflavin, the vitamin could then be removed from the plant substrate and the nodules continued to develop effectively. Impairment in the release of rhizobia from infection threads was observed in older nodules formed by TI/D-hisr-15 in the absence of riboflavin, the rhizobia becoming enveloped in large masses of polysaccharide-like material within the host cells.

Interrelationships between riboflavin and dietary energy and protein utilization in growing chicks.

1. Reduced intake of energy or protein per se decreased riboflavin requirement of the chicks under restricted feeding regimens.2. In severe riboflavin deficiency (2·26 mg/kg diet), efficiency of utilization of both energy and protein was decreased significantly under ad lib. conditions of feeding.3. Efficiency of utilization of energy (but not protein) was decreased significantly in border-line riboflavin deficiency (3·02 mg/kg diet), when chicks were fed ad lib.4. Efficiency of protein utilization was decreased significantly in severe riboflavin deficiency when chicks received an energy-restricted diet supplying 80, 70 or 60 yo of the energy intake of the controls.5. Neither energy nor protein utilization was affected by riboflavin deficiency when both energy and protein were restricted to 70 yo of that consumed by chicks fed ad lib. However, the riboflavin deficiency produced characteristic deficiency symptoms, namely heterophilia, curled-toe paralysis, and reduction in concentration of liver riboflavin.

Requirement for Riboflavin for Effective Symbiosis on Clover by an Auxotrophic Mutant Strain of Rhizobium Trifolii

A symbiotically ineffective auxotroph, Tl/D-hisr -15, derived from an effective strain (Tl) of R. trifolii, had a specific requirement for riboflavin in culture and produced an effective response on Trifolium pratense (red clover) only when riboflavin was added to the plant growth medium at c. 6 p.g/ml. Addition of flavin mononucleotide to the plant medium produced a similar response but the requirement in symbiosis was only partly satisfied by flavin adenine dinucleotide.

Thiamine requirement of the growing female Mongolian gerbil

The Mongolian gerbil, Meriones unguiculatus , has been used in studies of cholesterol metabolism (1–3), but its usefulness in other nutrition-related research has not been established. A semipurified diet which may be used as a basis for investigation of the nutritional requirements of this animal has been developed (4). The riboflavin requirement of the female gerbil has been studied (5), but other nutrients have not been investigated. It is the purpose of the present paper to study the thiamine requirements of the female gerbil.

The riboflavin requirement of the growing Mongolian gerbil

Growing gerbils fed a riboflavin-deficient diet showed decreased growth rate and severely depressed urinary excretion, but no observable eye, skin, or neuromuscular changes. Pair-fed animals also grew less well than controls. Growing female gerbils fed graded levels of riboflavin demonstrated slight, but not significant, growth retardation and severely decreased urinary riboflavin levels when fed 0.7 mg riboflavin per kilogram of ration. Urinary levels were sharply increased when animals were fed 3.5 mg riboflavin per kilogram of ration. In order to allow for other sources of variability, 7.0 mg per kilogram of ration is suggested as a “recommended allowance” of riboflavin in the diet of the gerbil.