Requirement Of Rat Research Articles

Corrected Relative Net Protein Ratio (CRNPR) Method Based on Differences in Rat and Human Requirements for Sulfur Amino Acids

The requirement for sulfur amino acids was calculated for growing rats fed 8% protein diets. The rat and human requirements for sulfur amino acids were compared and a correction factor was developed to reflect the differences. This correction factor was used to determine corrected relative net protein ratio (CRNPR) values for a number of potential meat extenders and their mixtures with beef. The methionine + cystine requirement of growing rats was estimated to be 4% of protein for 8% protein diets. The methionine + cystine requirement of rats was about 50% higher than that of humans (2.65% of protein). Based on this comparison (rat/human), a correction factor of 1.5 was developed to correct RNPR values of those protein products that were deficient in sulfur amino acids for rat growth. The CRNPR values of beef, casein, soybean protein products, pea concentrate, and peanut meal were 100, 100, 91-97, 75, and 73, respectively. Mixtures (50:50 protein basis) of beef with casein, soybean concentrate, soybean isolate, pea concentrate, peanut meal, rapeseed concentrate, rapeseed isolate, sunflower isolate, or wheat gluten were equal to beef in CRNPR values. The CRNPR method is a good predictor of protein quality for humans of those protein products that are deficient in sulfur amino acids.

Current determination of lithium-induced minimum sodium requirement in rats.

Lithium administration raises the minimum sodium requirement of the organism. Lithium treated-rats drink spontaneously a hypertonic sodium chloride solution and thereby protect themselves against the toxic effects of lithium. In the present paper it was studied whether the consumption of sodium chloride can be used as a quantitative measure of the sodium requirement. Rats given different amounts of lithium with food for about 2 months were given free access to water and a 0.46 M NaCl solution, and the 24-h intake of the latter was followed. It was found that the consumption of hypertonic sodium chloride increased with the lithium dosage and the serum lithium level. The consumption showed the following characteristics: (a) It was sufficient to prevent death from lithium poisoning. (b) When access to hypertonic chloride was discontinued for 48 h, the rats lost body weight; the body weight was reestablished within 1 h when the rats again had access to sodium chloride solution. (c) When sufficient amounts of sodium were given with the food, the lithium-treated rats drank no more sodium chloride solution than did the control rats. (d) When lithium administration was discontinued, the consumption of sodium chloride solution fell within 10 days to the control level. (e) The lithium-treated rats developed polyuria, but this was not the cause of the extra intake of sodium chloride. (f) The lithium-treated rats did not drink more of the hypertonic sodium chloride solution than was necessary to cover the minimum sodium requirement. The results indicate that the intake of hypertonic sodium chloride solution can, in fact, be used as a measure of the minimum sodium requirement in lithium-treated rats.

Determination of anesthetic requirement in rats.

Estimates of anesthetic requirement based on inspired anesthetic gas concentrations assume equilibration with alveolar, and consequently brain, anesthetic gas tensions. This assumption may be rendered invalid by the solubility of the anesthetic agent and its effects on ventilation. To test this assumption, ED50 values of anesthesia using halothane and a less soluble anesthetic, isoflurane, were determined in rats with and without tracheostomies. Alveolar ED50 or MAC for halothane and isoflurane were 1.11 ± 0.03 per cent and 1.38 ± 0.02 per cent, respectively. Inspired ED50 values 2–3 hours after induction in non-tracheostomized rats were 14 and 17 per cent greater, respectively, than alveolar ED50 values 2–3 hours following tracheostomy during halothane and isoflurane anesthesia in the same animals. These data demonstrate that previous studies in which the anesthetic requirement for halothane was determined using inspired gas samples are inaccurate. Inspired ED50 values for halothane and isoflurane in rats without tracheostomies were 2 and 11 per cent greater, respectively, than inspired ED50 values in the same animals with tracheostomies. Even after 3 hours of anesthesia in tracheostomized rats, measurements of inspired-to-alveolar differences in anesthetic gas tension revealed 9 and 3 per cent differences for halothane and isoflurane, respectively. Thus, the use of inspired concentration for this purpose in rats should be limited to inhalation anesthetics with low blood–gas partition coefficients and with minimal effects on ventilation. A moderately or highly soluble anesthetic agent or one which results in significant respiratory depression necessitates the direct measurement of “alveolar” anesthetic gas tension to determine anesthetic requirement.

Linoleic acid intake and vitamin E requirement in rats and ducklings.

Annals of the New York Academy of SciencesVolume 203, Issue 1 p. 199-211 LINOLEIC ACID INTAKE AND VITAMIN E REQUIREMENT IN RATS AND DUCKLINGS F. C. Jager, F. C. Jager Unilever Research Vlaardingen, The NetherlandsSearch for more papers by this author F. C. Jager, F. C. Jager Unilever Research Vlaardingen, The NetherlandsSearch for more papers by this author First published: December 1972 https://doi.org/10.1111/j.1749-6632.1972.tb27876.xCitations: 19AboutPDF 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 Volume203, Issue1Vitamin E and its Role in Cellular MetabolismDecember 1972Pages 199-211 RelatedInformation

Effect of Acacia catechu on niacin biosynthesis and on niacin requirement in rats.

The effect of feeding katha to rats at a level of 0.5 per cent of diet on the ‘in vitro’ and ‘in vivo’ biosynthesis of niacin and the niacin requirement of rats was studied.Katha feeding does not affect the biosynthesis of niacin in rats. However, the minimum daily requirement of niacin of rats fed katha is increased considerably.

Effect of phenobarbital on the development of fatty livers in choline-deficient rats.

The increase in hepatic phospholipid pool induced by phenobarbital did not affect the hepatic accumulation of fat produced by feeding rats a choline-deficient diet for 4 days. This lack of effect suggests that phenobarbital administration does not increase the choline requirement of rats, and/or that phenobarbital and choline deficiency act on different loci within the hepatic cell independently of each other.

High linoleic acid intake and vitamin E requirement in rats.

High linoleic acid intake and vitamin E requirement in rats.

Determination of vitamin E requirement in rats by means of spontaneous haemolysis in vitro.

Determination of vitamin E requirement in rats by means of spontaneous haemolysis in vitro.

Effect of cold on the vitamin E requirement of rats.

SINGH1 has suggested that man's vitamin E requirement increases at high altitudes. Vitamin E is known to be involved in the transport of oxygen in the respiratory chain, and it could facilitate oxygen transport during enzyme adaptation to hypoxia. At an altitude of 3,450 m and a temperature of 20° C, rats have shown neither an increased requirement for vitamin E nor an improved fitness when given vitamin E2,3. These negative results were found at constant conditions of ambient temperature at which the oxygen consumption at a high altitude is known to be low2. The turnover of vitamin E would be expected to increase with any increase in oxygen consumption, and because temperature decreases with altitude and oxygen consumption increases with decreasing temperature, the greater requirement for vitamin E postulated by Singh1 could be caused by exposure to cold and not by hypoxia at a high altitude. We have investigated the vitamin E requirement of rats at high and low temperatures independent of altitude.

Environmental temperature and choline requirement in rats. I: Choline deficiency in rats at various temperatures

Rats were maintained at 2 degrees, 21 degrees, and 33 degrees for 3 weeks on a choline-supplemented or a choline-deficient diet. In contrast to the findings of some other workers, choline deficiency produced fatty livers at all temperatures. The ratio of the total liver lipid to the total food intake was the same in all choline-supplemented rats. In choline-deficient rats this ratio was always higher and varied directly with temperature.

Environmental temperature and choline requirements in rats. II: Choline and methionine requirements for lipotropic activity

Young rats were fed choline-deficient diets and maintained at different environmental temperatures. The hepatic lipid level remained normal in rats at 2 degrees when 25 mg of choline per 100 g of food was fed; 50 mg of choline per 100 g food was required at 21 degrees and 100 mg of choline per 100 g food at 33 degrees to prevent excessive lipid accumulation. These values were equivalent to a mean daily intake per rat of 3 mg of choline at 2 degrees, 5.5 mg at 21 degrees, and 7 mg at 33 degrees respectively. When the growth rate was slower owing to a slight inadequacy of histidine in the basal choline-deficient diet, normal hepatic lipid was maintained by supplements of 50 mg of choline per 100 g food at 21 degrees and 33 degrees. Increasing the methionine content of the diet two- or three-fold from a basal value of 340 mg per 100 g food was as effective as 200 mg of choline per 100 g of food in lowering hepatic lipids at 2 degrees, 21 degrees, and 33 degrees.

Sparing Action of Protein on Pantothenic Acid Requirement of Rat. III. Fibrin as the Protein Component.

SummaryThe sparing action of protein on the pantothenic acid requirement of the rat has been confirmed by using a protein considerably lower in pantothenic acid, washed beef blood fibrin, instead of casein as the protein component of the diet. Despite the accentuation of the pantothenic acid deficiency produced by substituting purified fibrin for casein at the 24% level, doubling the fibrin level resulted in significantly better growth and survival. The differences in growth and survival between the two protein levels in the fibrin-containing diets were more pronounced than those observed for the casein-containing diets. The protective effects of the high fibrin diet indicated also that phosphorus can be eliminated as a possible factor concerned in the sparing action.

Strain Differences in the Choline Requirement of Rats.

SummaryTwo strains of rats were selected which showed significant differences in their requirement of choline. Tests on the progeny of each strain proved that this difference continued through the F3 generation. The minimum daily choline requirement of the strain LCR was approximately 4 to 6 mg per rat on diet 31PMC, and the minimum daily choline requirement of the strain HCR on the same diet was above 10 mg per rat.

Inherited Differences in the Choline Requirement of Rats.

SummaryTwo strains Of rats were developed which in their second generation differed markedly in their requirement of dietary choline.

Effect of an Excess of Salt on Resistance to Histamine in Rats

An excess of salt for short periods above the apparent requirement in rats in which the depôts of saline solution have been filled enhances the natural resistance of the animal to large amounts of histamine. The intraperitoneal injection of large quantities of saline a few hours prior to the test increased the resistance to twice the normal. Salt feeding for several days prior to the test raised resistance about 30 to 40%.

The Effect of the Vitamin A (Carotene) Intake on the Vitamin D Requirement of Rats in the Production and Cure of Rickets

The Effect of the Vitamin A (Carotene) Intake on the Vitamin D Requirement of Rats in the Production and Cure of Rickets