Various Levels Of Dietary Protein Research Articles

Effect of Various Levels of Dietary Protein in Transition Period on Colostrum Quality and Serum Immunoglobulin Concentration in Holstein Cows and their Newborn Calves

Abstract This experiment was conducted to investigate the effect of 2 levels of crude protein (CP) content in the diet during transition period on lactation performance, colostrum quality and serum immunoglobulin concentration of dairy cows and their newborn calves. Thirty dry Holstein cows (607±75 kg) were blocked according to their parity and expected calving date, and then randomly assigned to one of 2 treatments of 15 cows in completely randomized block design. Dietary treatments were: 1) moderate CP level in transition diet (prepartum: 11.9%; postpartum: 14%); and 2) higher CP level in transition diet (prepartum: 14.2%; postpartum: 16.8%). Furthermore, milk samples were collected on two days (15 and 30) postpartum for milk composition analysis. At the same time, milk yield also was recorded. After parturition calves were fed mother’s colostrum. Colostrum samples were collected during the first milking postpartum. Blood samples of cows were taken on days 21 and 2 before projected calving date and on days 15 and 30 after parturition. Blood samples of calves were collected at 72 h postcalving and then on days 7, 14, 21 and 28 after birth. Applied treatment had no effect on average milk production on days 15 and 30 postpartum. Colostrum density was lower in cows fed higher CP level in transition diet than in those fed the diet with moderate CP content (P<0.05). However, the chemical composition of colostrum was not affected by CP level. Serum IgG concentration was higher for calves from higher CP group than for those from moderate CP level group at 21 days of age (P<0.05). In conclusion, the increased protein level during periparturient period tended to improve immune status of calves.

메추리에 있어서 산란 사료 내 단백질 수준이 산란 성적과 난질에 미치는 영향

본 연구는 산란 메추리에서 사료 내 조단백질 수준이 생산성과 난질에 미치는 영향을 조사하기 위하여 실시하였다. 총 640수의 7주령 메추리(Coturnix coturnix japonica)를 공시하여 모두 4개 처리구에 8반복(반복당 20수)으로 임의 배치하여 8주간 사양실험을 실시하였으며, 실험 사료는 옥수수 대두박을 기초로 하여 대사 에너지 2,800 kcal/kg에 조단백질 수준을 18%, 20%, 22% 및 24%로 각각 달리하여 급여하였다. 전체 실험기간의 수당 사료 섭취량과 난중에서는 처리간에 유의성 있는 차이가 관찰되지 않았다. CP 24% 처리구의 산란율과 일산란량은 CP 18% 처리구에 비해 유의하게 높았다(P<0.05). 난각 두께 및 Haugh unit 항목에서는 유의적인 차이를 보이지 않았다. 혈청 내 albumin, BUN, creatinine 농도 및 GOT, GPT의 효소 활성 농도는 처리구간에 유의적인 차이가 나타나지 않았다. 맹장 내 암모니아 농도는 처리구 간에 변화가 관찰되지 않았으며, 간 내 중성지질 함량은 CP 18% 처리구에 비해 20%이상 급여한 모든 처리구에서 유의하게 감소하였다(P<0.05). 본 실험 결과, 난용메추리 사료 내 조단백질 함량이 상대적으로 높은 조건에서 난생산성이 증가하였으며, 간 내 중성지질 축적이 감소한 것으로 나타났다. 또한 단백질 수준의 범위를 더 넓히고 세분화된 연구가 더 필요하리라 판단된다. This experiment was conducted to investigate the effects of various levels of dietary protein on laying performance and egg quality in laying quail. A total of six hundred forty 7-week-old laying type Japanese quail were divided into four groups with eight replicates per group (20 birds per replicate) and fed four diets differing in dietary protein levels (18, 20, 22 and 24%) with isocaloric corn-soybean meal-based diets for 8 weeks. The results showed no significant differences in feed intake and egg weight among the groups. With an increase in dietary protein levels, the egg production and daily egg mass were linearly increased (P<0.05). However, there were no significant differences in eggshell thickness and Haugh unit. The dietary protein did not affect the blood levels of GOT, GPT, BUN, albumin, and creatinine. The ammonia concentration of intestinal digesta was not affected by the dietary treatments. The contents of hepatic triacylglycerol in the groups fed diets containing 20% protein or more were significantly reduced as compared with that of 18% CP group (P<0.05). Overall, this study showed that relatively high levels of dietary CP are needed to sustain the higher egg production and daily egg mass and to avoid the hepatic triacylglycerol accumulation in Japanese quail.

The Effect of various levels of dietary protein and lipid on growth and body composition of Acipenser persicus fingerlings

Summary A 20 week feeding with three dietary protein levels (40, 45 and 50%) and four dietary energy levels (18.5, 19.8, 22.1 and 22.4 MJ kg−1) by range (P/E) ratios of 17.86–26.85 mg protein kJ−1 was conducted to investigate optimum protein, energy and protein to energy (P/E) for final weight (FW), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER) and Hepatosomatic index (HSI) Acipenser persicus Fingerling (Average weight 10.26 ± 0.11). Study was carried out in 3 × 4 factorial design. Acipenser persicus Fingerlings reared in fiberglass tank (500 L water volume) and fed to apparent satiation fourth daily. At the end of the experimental period six fish were sampled randomly from each replicate, killed and were preserved at −20°C for body composition analysis and Hepatosomatic index. The same energy level, increase in dietary protein from 40 to 45% resulted in significant increases in the final weight (FW) and Increase in protein levels from 40 to 45 and 50% led to a significant increase in (PER) Protein efficiency ratio fishes (P < 0.05). At similar protein levels, increasing energy from 18.5 MJ kg−1 to higher levels (21.1 and 22.4 MJ kg−1) resulted in a significant increase in W2 and PER values and an improvement of FCR (P < 0.05). Highest FW belonged to fish fed diet 7 (45% protein and 21.1 MJ kg−1) followed by fish fed diet 8 (45% protein 22.4 MJ kg−1) and fish fed diet 4 (40% protein and 22.4 MJ kg−1). Increase in dietary energy level from 18.5 to 24.4 MJ kg−1 resulted a accumulation of lipid in carcass. The highest body lipid and protein showed in fishes fed diet 3 (40% protein and 22.1 MJ kg−1) and 4 (40% protein and 22.4 MJ kg−1). The present study showed that diets containing 40% protein and 20.1–25.9% lipid with a P/E ratio of 17.86 mg kJ, prepared from good quality ingredients can meet the dietary requirements of A. persicus fingerlings without leaving adverse effects on the biochemical composition of the body.

Evaluation of a Dietary Organic Selenium Supplement at Different Dietary Protein Concentrations on Growth Performance, Body Composition and Antioxidative Status of Broilers Reared under Heat Stress

Three hundred chicks were randomly assigned among four treatments to evaluate the effect of an organic selenium supplement at various levels of dietary protein. Two levels of supplemental selenium (0 and 0.3 mg/kg) from zinc-L-selenomethionine were tested at two levels of dietary protein (normal and reduced) in a completely randomized design with 2x2 factorial layout. The experiment lasted up to 49 d of age during which all birds were exposed to 31±1°C. The effects of selenium or its interaction with CP on growth performance and carcass characteristics were not significant. However, feeding the reduced-CP diet decreased weight gain in the starting period and increased liver and abdominal fat weights relative to body weight. Ferric reducing ability of plasma (FRAP) was not significantly affected by dietary CP and Se or their interaction though FRAP values were numerically higher in the Se-supplemented group. Dietary CP content did not affect the activity of plasma glutathione peroxidase (GSHPx), though Se significantly elevated plasma GSHPx activity. The interaction of CP and Se was not significant for FRAP and plasma GSHPx activity.

Comparison of Channel Catfish, Ictalurus punctatus, and Blue Catfish, Ictalurus furcatus, Fed Diets Containing Various Levels of Protein in Production Ponds

Abstract A comparative study was conducted on growth and protein requirements of channel catfish, Ictalurus punctatus, and blue catfish, Ictalurus furcatus. Four diets containing 24, 28, 32, or 36% protein were fed to both channel (initial weight 6.9 g/fish) and blue (6.6 g/fish) catfish for two growing seasons. There were significant interactions between dietary protein and fish species for weight gain and feed conversion ratio (FCR). No significant differences were observed in weight gain of channel catfish fed various protein diets, whereas higher protein diets (32 and 36%) resulted in better weight gain in blue catfish than lower protein diets (24 and 28%). No consistent differences were observed in the FCR of channel catfish fed various levels of dietary protein, whereas significantly higher FCRs were noted in blue catfish fed the 24 and 28% protein diets compared with fish fed 32 and 36% protein diets. Regardless of dietary protein levels, blue catfish had higher carcass, nugget, and total meat yield, and higher fillet moisture and protein, but lower fillet yield and fillet fat. Regardless of fish species, fish fed the 36% protein diet had higher carcass, fillet, and total meat yield than fish fed the 28 and 32% protein diets, which in turn had higher yields than fish fed the 24% protein diet. It appears that blue catfish can be successfully cultured by feeding a 32% protein diet.

Evaluation of Practical Diets with Various Levels of Dietary Protein and Animal Protein for Pond‐Raised Channel Catfish Ictalurus punctatus1

AbstractThree levels of dietary protein (26, 28, or 32%) and four levels of animal protein (0, 2, 4, or 6%) were evaluated in a factorial experiment for pond‐raised channel caffish using practical‐type extruded feeds. Meat, bone, and blood meal (65% protein) was used as the animal protein source. Channel catfish fingerlings (average weight: 69 glfish) were stocked into 48 0.04‐ha ponds at a rate of 24,700 fishha. Four ponds were used for each dietary treatment. Fish were fed once daily to apparent satiation for 158 d. No differences were observed in weight gain, feed consumption, feed conversion ratio, survival, and hematocrits of channel catfish fed diets containing various levels of dietary protein and animal protein. Inclusion of animal protein in the diet did not affect fish dressout, percentage visceral fat, or fillet composition. Comparison of means pooled by dietary protein without regard to animal protein showed that fish fed diets containing 26% protein had a lower percentage dressout than fish fed higher protein diets (55.4% vs. 56.3%). Fish fed the 32% protein diet had lower visceral fat than those fed the 26% or 28% protein diet (2.9% vs. 3.6% or 3.4%). Fillet fat was lower for fish fed the 32% protein diet than for fish fed the 26% protein diet (5.8% vs. 7.1%). Fillet fat in fish fed the 28% protein diet (6.5%) was not different from fish fed either 26% or 32% dietary protein. No differences were detected in fillet protein, moisture, and ash concentrations among fish fed diets containing various concentrations of protein. There were no interactions between dietary protein and animal protein for any variables. Results from the present study indicate that animal protein can be eliminated from diets for grow out of channel catfish fed to apparent satiation using diets containing 26% to 32% crude protein.

Canine Colonic Microstructure and Function as Affected by the Level of Dietary Protein

Fifteen adult mongrel dogs, 5-24 kg body wt, were fed one of three diets that varied in the level of dietary protein (12%, 24% or 36%). Dogs were fed their re spective diets for a minimum of 14 d before experi mentation. Colonie function was evaluated by in vivo perfusion, cecum to rectum, of 90-min duration. Tis sues were collected from the proximal, mid and distal colon for analysis of oxygen consumption rate, protein content and mucosal morphology. Oxygen consump tion rate (tissue energetics) was measured over time with glucose as the substrate. Colonie mass (1.33%, 2.45% and 2.57% body wt) and protein content (0.63, 1.10 and 1.16 g/kg body wt) (12, 24 and 36%, respec tively) were significantly less (P < 0.05) in dogs fed the 12% compared with those fed 24 and 36% protein diets. In addition, tissue energetics (0.21,0.44 and 0.57 urn O2'g~1'min~1 increased significantly with each increase in dietary protein (12, 24 and 36% protein, respectively). Significant differences were also noted in tissue energetics for the proximal, mid and distal colonie segments. Morphometric studies revealed a larger (P < 0.05) ratio of colonie surface area to mu cosal volume in dogs fed the 24% and 36% diets rel ative to those fed the 12% protein diet. Colonie trans port of sodium, chloride and individual fatty acids (acetate, propionate and butyrate) were significantly different for the various dietary protein levels. Signif icant differences in effluent pH, osmolality, bicarbon ate and base excesswere also noted among diet groups. The data suggests that the canine large bowel acts as a protein sink, accumulating protein with the in creased dietary level. Furthermore, colonie structure and tissue energetics adapt to various levels of dietary protein, resulting in a modification of the absorptivesecretory process of the bowel.

Effect of different levels of protein intake on renal deterioration and nutritional state in experimental renal disease.

We examined the effects of various levels of dietary protein on the course of adriamycin-induced nephropathy in rats fed with high (30%), intermediately low (10%) or strictly low (5%) protein diets for 24 weeks. In the rats fed on the 30% protein diets, there were massive proteinuria, progressive increases in serum creatinine and focal glomerular sclerosis associated with severe tubulo-interstitial changes. With the 5% dietary protein, proteinuria was decreased, the levels of serum creatinine were preserved within normal ranges and renal histological changes diminished. Weight loss and hypoproteinaemia were more marked. With intermediate protein restriction (10% protein), renal function and plasma protein were preserved but body weight did not increase normally. Aggregated human immunoglobulin G, which had been intravenously injected at weeks 12 and 24, accumulated in the glomeruli more densely in rats fed on the 30% protein diet than in those fed on the 10% or 5% protein diets. We tentatively conclude that functional and histological deterioration of focal glomerular sclerosis can be prevented by appropriate restriction of dietary protein; however, severe protein restriction does aggravate nutritional states.

Mechanical Properties of the Tibiotarsus of Broilers and Poults Loaded with Artificial Weight and Fed Various Dietary Protein Levels

Bone strength comparisons were made on tibiotarsi of chicks and poults fed various levels of dietary protein and either loaded or not loaded with artificial weights. Stress and modulus of elasticity were evaluated for their ability to measure strength and rigidity differences in bones while accounting for various bone size. Often comparisons between birds of different ages and body weights are attempted despite various bone size and dimension. These terms identified the weaker, less rigid bones in a comparison between chicks fed a low calcium, low phosphorus diet and a control group matched for age, weight, and bone size. Stress values were not significantly different when ad libitum-fed controls and restriction-fed controls were compared even though body weights were significantly different. This suggests that bone strength comparisons can be made on bones that differ in size.Artificial weight loading of chicks or poults had no consistent effect on stress or modulus of elasticity. This would suggest that this type of exercise had no influence on bone strength. Turkey poults fed 28% dietary protein appeared to have stronger bones than those fed lower protein levels; however, when bone size and dimension are accounted for, no differences in bone strength resulted from the feeding of various protein levels. These findings suggest that stress and modulus of elasticity are better terms to use than force in making bone strength comparisons between groups of birds which may differ in body size and bone dimension.

Effects of dietary protein and calcium on the skeleton of undernourished young rats.

A study has been made of the effects of various levels of dietary protein and calcium on the skeleton of young undernourished rats. The data for the study were obtained from physical properties of bone, from microradiographs of various parts of femur and histological sections of the bone. There were significant associations between a low protein intake and low bone mass, irrespective of calcium intake, and between a high protein intake and a high bone density at a normal calcium content of the diet. The influence of dietary protein on the composition of the bone was dependent on the calcium intake. Reduction in the protein level was associated with less trabecular bone and reduction in the calcium reduced mainly the amount of cortical bone.

Adaptive responses of glutamine, ammonia and uric acid in tissues and urine to ammonia load in chickens fed various levels of dietary protein

1. 1. This experiment was carried out to examine metabolic responses to ammonia loads in nitrogen metabolism of chickens fed 0, 5, 20 and 40% protein diets. 2. 2. All the chickens fed the experimental diets showed large increases in urinary ammonia corresponding to 29–48% and 11–15% of the administered ammonia when 3 or 6mmol ammonia was infused, respectively, as well as tissue ammonia increases of 5–12% of the infused ammonia. 3. 3. The chickens fed the 0 and 5% protein diets responded to 3 and 6 mmol ammonia loads with increases in tissue glutamine of 7–16% of the infused ammonia and with little or no increases in total uric acid. 4. 4. The chickens fed the 20 and 40% protein diets increased in total uric acid in tissues and urine by 27 and 15% of the infused ammonia, respectively and in very little amount in tissue glutamine (below 2%) in response to both amounts of ammonia load.

Effects of various levels of dietary protein on survival, molting frequency and growth of juvenile blue crabs ( Callinectes sapidus)

An 18-week study was conducted to examine growth characteristics of the juvenile blue crab ( Callinectes sapidus Rathbun) fed various levels of dietary protein. Hatchery raised individuals (157) of identical age (160 days) from the same gravid female were assigned to one of four dietary treatments: adult brine shrimp ( Artemia salina Leach) and artificial pelleted diets containing crude protein levels of 23, 37, and 49%. Growth rate, measured as a function of mean weight and mean carapace width, indicated that brine shrimp-fed crabs were larger ( P < 0.05) than crabs fed artificial pelleted diets. Also, blue crabs fed either 37 or 49% crude protein were larger than crabs fed the 23% crude protein diet. Molting frequency was greater in the brine shrimp-fed crabs than in those fed the artificial diets. No differences in growth were detected when comparing males vs. females fed the artificial diets. However, females demonstrated greater growth than males within the brine shrimp treatment. Protein concentration of freeze-dried whole blue crab carcasses was greater in brine shrimp-fed crabs than in crabs fed the artificial pelleted diets ( P < 0.05).

Preliminary observation on the dietary protein requirement of estuary grouper, Epinephelus salmoides Maxwell, cultured in floating net-cages

The dietary protein requirement of young estuary grouper, Epinephelus salmoides, in floating net-cages was examined. Six experimental diets of a similar calorie content ( 324–341 kcal 100 gm dry diet), containing protein at equally spaced concentrations between 20 and 70% dry diet, were tested. Sun-dried muscle from tuna ( Euthynnus affinis) was used as the source of protein. The experiments were conducted for a period of 12 weeks and the growth response of fish to each experimental diet was calculated in terms of weight-gains, feed conversion and protein efficiency ratio (PER). At the end of the experiments, the total weight-gains of fish for each diet tested were found to be linearly dependent on their initial weights. Equations of linear regression of weight-gains on initial weights of fish were calculated for each diet. A response-curve of the fish to the various levels of dietary protein tested was constructed from weight-gains of the fish with the same initial weight. The level of dietary protein that produced the maximum weight-gain of fish was estimated from the response-curve to be at 50% (protein calorie to energy calorie ratio = 1 : 0.63). However, weight-gain of fish at 40% dietary protein (protein calorie to energy calorie ratio = 1 : 1.06) was not significantly different from that at 50% dietary protein. Higher efficiency of feed conversion and higher values of PER were recorded at these two levels of dietary protein. Growth of fish was greatly de-pressed when they were fed on diet containing 20 or 30% protein (protein calorie to energy calorie ratios of 1 : 3.12 or 1 : 1.70, respectively). When the dietary protein is increased from 50% to 60 or 70% with protein calorie to energy calorie ratio at 1 : 0.37 or 1 : 0.22, respectively, the growth of fish was not appreciably enhanced. For a given length, fish fed on diets containing 40–50% protein were heavier, thus more robust than those at any other diets tested. In view of these facts, the diet that contains 40% protein with protein calorie to energy calorie ratio at 1 : 1.06 is perhaps the most economical when formulation of a practical fish feed is considered.

The effects of various levels of dietary protein on retinoic acid-induced teratogenicity in rats.

AbstractThe teratogenic effects of single oral doses of 10 mg/kg retinoic acid given on day 9 of pregnancy was compared in rats fed 2.5, 5, 10, 20, or 30% dietary protein. Low levels of dietary protein alone did not affect reproduction and were not frankly teratogenic, but did retard skeletal ossification in fetuses of females fed 2.5% protein. Fetal growth was depressed in the groups fed 2.5, 5, or 10% protein. In rats treated with retinoic acid the resorption rate and the incidence of defective fetuses was increased by protein deficiencies. Serum analyses on gestation days 3, 9, and 21 revealed significantly lower BUN levels on days 9 and 21 in females fed 2.5 or 5% protein compared to those fed 20 or 30% protein, but the total proteins and albumin were not lower in these two groups until day 21. The administration of retinoic acid increased the level of protein in sera and livers and decreased the level of liver lipids in rats fed the lower levels of dietary protein, indicating that the retinoic acid increased protein synthesis.

The Effect of Various Levels of Dietary Protein on the Growth and Egg Production of Coturnix Coturnix Japonica

A NUMBER of reports are available on the protein requirement of Bobwhite quail. Initially, a level of 27% dietary protein was suggested by Norris (1935) but other workers preferred a level of 28% protein (Nestler et al., 1942; Stadelman et al., 1945; Baldini et al., 1950). When the diet was adequately supplemented with lysine, Baldini et al. (1953) found that diets containing 20% protein supported the growth of Bobwhite quail satisfactorily. Scott et al. (1963) recommended diets containing 26.5% protein.As the interest in the study of Japanese quail (coturnix) developed, the maintenance of populations on diets containing about 28% crude protein was adopted (Woodard et al., 1965). Recent studies indicate that coturnix can be started on diets containing 25–26% protein (Weber and Reid, 1967; Vogt, 1967, 1969; Lepore and Marks, 1968; Svacha et al., 1970) and this level can be reduced to 20% after 3 weeks (Vogt, 1967;…

Reproductive Performance of Rats Receiving Various Levels of Dietary Protein and Fat

Female rats fed practical diets containing 18 or 25% protein produced and weaned a few more young than those fed 30 or 35%. Females fed purified diets containing 14, 17 and 20% soybean protein in different periods of the reproductive cycle produced as many young as the control group which consumed 25% soybean protein. With 10% protein throughout the cycle, the number of young and weaning weight were reduced to less than those of the controls. With 10% protein during mating and gestation period, the number weaned and their weight was essentially equal to that of the control group. With 14% protein during 2 or more periods, the weight was less than that of the young in the control group. The number of young weaned by females fed a practical diet containing 3 to 18% fat was essentially the same but the number weaned was less with 25% fat. With a purified diet reproduction by females consuming 3 or 20% fat was superior to those fed 36 and 50%. When the protein-metabolizable energy was adjusted to a constant ratio (0.074 to 0.070) the effect of a high fat diet on the number of young weaned and the weaning weight was very small.

The Effect of Various Levels of Dietary Protein upon the Volatile Fatty Acids in the Rumen of the Dairy Cow

Volatile fatty are the end products of the hydrolysis of complex carbohydrates produced by the bacterial population in the rumen. Nine cows were used in a feeding experiment to determine the influence of the amount of protein in the ration of a ruminant upon the level of volatile fatty formed. Experimental periods were 21 days in length. Increased amounts of volatile fatty except higher acids were observed as a result of high levels of protein intake. Editor.

Chronic effect of dietary protein on hypercholesteremia in the rat.

SummaryChronic dietary experiments in rats have revealed that months are necessary to evaluate the ultimate level of serum lipids resulting from sustained feeding of various levels of dietary protein. Quantitative changes in dietary protein can influence the levels of serum cholesterol and cholesterol/lipid phosphorus ratio. Reduction or elevation of dietary casein beyond a modest range (12-18%) will lead to ultimate elevation of serum cholesterol and phospholipid under conditions herein described. The insignificant change in cholesterol/lipid phosphorus ratio at low levels of dietary casein as opposed to its elevation at higher levels suggests that different mechanisms are operating in these two situations. Unusually high levels of serum cholesterol were achieved in old rats fed 40% casein. Coronary arterial atheromatous lesions developed in one-third of these animals, but in none of the other groups in the 6-month period.

The effects of various levels of dietary protein on skeletal growth and endochondral ossification in young rats.

The effects of various levels of dietary protein on skeletal growth and endochondral ossification in young rats.

The Effects of Various Levels of Dietary Protein on the Periodontal Tissues of Young Rats

The Journal of PeriodontologyVolume 24, Issue 3 p. 135-142 The Effects of Various Levels of Dietary Protein on the Periodontal Tissues of Young Rats Asger M. Frandsen D.D.S., Asger M. Frandsen D.D.S. San Franciso and Berkeley, CaliforniaSearch for more papers by this authorHermann Becks D.D.S., Hermann Becks D.D.S. San Franciso and Berkeley, CaliforniaSearch for more papers by this authorMarjorie M. Nelson PH.D., Marjorie M. Nelson PH.D. San Franciso and Berkeley, CaliforniaSearch for more papers by this authorHerbert M. Evans M.D., Herbert M. Evans M.D. San Franciso and Berkeley, CaliforniaSearch for more papers by this author Asger M. Frandsen D.D.S., Asger M. Frandsen D.D.S. San Franciso and Berkeley, CaliforniaSearch for more papers by this authorHermann Becks D.D.S., Hermann Becks D.D.S. San Franciso and Berkeley, CaliforniaSearch for more papers by this authorMarjorie M. Nelson PH.D., Marjorie M. Nelson PH.D. San Franciso and Berkeley, CaliforniaSearch for more papers by this authorHerbert M. Evans M.D., Herbert M. Evans M.D. San Franciso and Berkeley, CaliforniaSearch for more papers by this author First published: 01 July 1953 https://doi.org/10.1902/jop.1953.24.3.135Citations: 28 From the Division of Dental Medicine, College of Dentistry, the George Williams Hooper Foundation for Medical Research, and the Institute of Experimental Biology, University of California, San Francisco, and Berkeley. Aided by grants from the American Foundation for Dental Science, the Board of Research and the Department of Agriculture of the University of California, the Roche Anniversary Foundation, and the California State Dental Association. The following materials were generously contributed: crystalline B vitamins and alphatocopherol from Merck and Company, Inc., Rahway, New Jersey; liver powder (lab. no. 7-5293) from Lederle Laboratories, Inc., Pearl River, New York. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume24, Issue3July 1953Pages 135-142 RelatedInformation