Purified Casein Diet Research Articles

The impact of maternal in utero environment on salt‐induced hypertension in the SS rat

The SS rat is an established model of salt‐sensitive human hypertension. We previously demonstrated that SS animals from parents fed a grain‐based diet are less susceptible to salt‐induced elevations in blood pressure and associated renal damage than SS animals fed a casein‐based protein diet. Others have shown that transfer of SS strain embryos into genetically unrelated recipients can also attenuate salt‐induced blood pressure changes. We hypothesized, therefore, that differences in dietary‐induced susceptibility may be driven by the in utero environment of pregnant females fed these different diets. Using the closely related SS/JrHsdMcwi strain (SS/Mcw), maintained on a purified casein diet, and the SS/JrHsdMcwiCrl (SS/Crl) which is maintained on a grain diet, we addressed this hypothesis by performing embryo transfers between strains and phenotyping the offspring. Compared to control male rats (n=6) generated by the transfer of SS/Mcw embryos into SS/Mcw females, males (n=9) generated by transfer of SS/Mcw embryos into SS/Crl female recipients demonstrated both significantly reduced mean arterial pressure (154 ±7 mmHg vs. 134±6) and lower urinary albumin excretion (200±19 mg/day vs. 74±14 mg/day) following three weeks of a 4.0% NaCl diet. These data demonstrated that the dietary exposure of pregnant SS female rats can impact the susceptibility of their offspring to salt‐induced hypertension.

Chronic Effects of Dietary Selenium on Juvenile Sacramento Splittail (Pogonichthys macrolepidotus)

The chronic effects of dietary selenium (Se) exposure in juvenile Sacramento splittail (Pogonichthys macrolepidotus) were investigated in the laboratory. A total of 960 (40 fish per tank, 3 tanks per diet) 7-month-old juvenile splittail were fed one of eight Purified-Casein diets supplemented with selenized yeast for 9 months in a flow-through system. These diets contained the following: 0.4 (control), 0.7, 1.4, 2.7, 6.6, 12.6, 26.0, and 57.6 mg of Se kg(-1) dry weight. Survival, Se tissue concentration, growth, gross morphology, and liver histopathology were assessed at 5- and 9-month of exposure. Mortalities occurred only in the two highest Se treatments and were accounted for 8.3 and 18.3% at 5-month and 10.0 and 34.3% at 9-month, respectively. Liver and muscle Se concentration were significantly correlated with dietary Se concentration. Fish exposed to 0.4-12.6 mg of Se kg(-1) diets had reached equilibrium in liver Se concentration by 5 month. Splittail fed diets at concentrations > or =26.0 mg of Se kg(-1) had not reached equilibrium in liver, and muscle Se concentrations and grew significantly slower (p < 0.05) at 5- and 9-month exposure. Se-induced deformities were observed in fish fed > or =2.7 mg of Se kg(-1) diets at 5-month and in fish fed > or =0.7 mg of Se kg(-1) diets at 9-month. Fish fed 26.0 and 57.6 mg of Se kg(-1) diets had higher liver lesion scores at 5-month while fish fed 6.6 and 57.6 mg of Se kg(-1) diet had higher liver lesion scores at 9-month. Results indicate that survivals, growth, changes of tissue Se concentrations, and histopathology of juvenile splittail were dose-dependent, but their response thresholds to dietary Se concentrations differed and depended on treatment concentrations and duration of exposure. Chronic exposure to 6.6 mg of Se kg(-1) diet induced deleterious health effects that can potentially impact survival of juvenile splittail.

Effect of Diets and Water Temperatures on Growth Performance of Splittail Larvae

A 4-week growth trial using a 4 × 3 × 2 factorial design (consisting of four diets, three water temperatures, and two replications of 150 larvae each) was conducted with splittail Pogonichthys macrolepidotus larvae (16 d posthatch, weighing 3.1 ± 0.5 mg [mean ± SE] and measuring 8.9 ± 0.2 mm) in three recirculation systems. The four diets were three commercial feeds (Silver Cup [SC], BioDiet [BD], and Biokyowa [BK]) and a laboratory purified-casein (PC) diet. The three water temperatures were 18, 22, and 26°C. Results indicated that the specific growth rate, total body length, condition factor, and whole body moisture of the fish were significantly (P < 0.05) affected by the diets and water temperatures, whereas mortality was only affected by the diets. The interaction of diet and water temperature was significant for the specific growth rate, total body length, whole body moisture, and mortality but not for the condition factor. Larvae fed the BK and PC diets had a higher specific growth rate and lower mortality than those fed the SC and BD diets at all temperatures. Larvae raised at 26°C grew faster and were thus significantly longer and heavier than those raised at 18°C. These results suggest that the BK or laboratory PC diet and a water temperature of 26°C were better than the other commercial feeds and water temperatures for splittail larvae under our laboratory conditions.

Diet selection by chicks

Seven experiments with 324 chicks tested their ability to select a nutritionally adequate diet from separate sources of purified casein and various supplements, including gelatin (a source of two amino acids), a gelatin-creatine mixture (a source of three amino acids), and fiber (nonnutritive bulk). Nonselecting controls consumed the basal purified-casein diet or a supplemented purified-casein diet. Chicks in all selection conditions composed diets that yielded normal intake, normal body temperature, normal activity, and the maximum growth possible for their intake. They also selected components in the same percentages as in premixed diets. In all instances, their selection was nonrandom and regulated. What chicks included in their diet depended on what else was available. Although the specific percentage taken from each dietary component varied across different selection alternatives, these differences affected neither intake nor growth. Selection, per se, incurred a caloric cost. Chicks selecting from fractions of a corn-and-soy diet offset this cost by increasing intake compensatorily, but chicks with a purified-casein fraction did not, suggesting that some unspecified property of casein placed a ceiling on its intake. These findings unequivocally demonstrate that immature chicks not only can self-select nutritionally adequate diets, but can do so with unexpected precision by exploiting different but equally successful strategies.

カサゴに対する摂餌促進物質の同定

Feeding stimulants for the marbled rockfish Sebasticus marmoratus were identfied by the omission test uding the synthetic extract of krill Euphausia pacifica. The fish were fed on a purifiedcasein diet supplemented with constituents of the extract for 6 days. The feeding stimulant activity was evaluated by the daily feeding rate. The nucleotide fraction of the extract was the most effective, followed by the amino acid fraction which showed a littel activity. Inosine had the highest activity among all constituents of the extract. With increasing supplementary level to the diet, amino acids such as L-alanine, L-methionine, L-serine and L-proline and nucleotides such as adenosine-5'-diphosphate, adenosine-5'-monophosphate and inosine-5'-monophosphate became positive. When inosine together with, L-alanine, L-methionine, L-serine and L-proline was supplemented to the diet, its activity for the fish was remarkably improved, becoming to the synthetic extract.

Induction of hyperplasia in the bladder epithelium of rats by a dietary excess of acid or base: Implications for toxicity/carcinogenicity testing

In previous studies we observed an increased incidence of hyperplasia in the epithelium of the urinary bladder of rats fed cereal-based stock diet supplemented with 6% monosodium glutamate (MSG) for 3 months. Hyperplasia was not enhanced, however, when 6% MSG was fed in a purified casein diet. Further studies have been conducted to identify the dietary factor that caused the different response with the two diets. Feeding MSG had a marked alkalizing effect on the urine. Rats fed purified diet produced urine of higher acidity than did those fed stock diet, a finding attributed to the greater excess of base in the stock diet. When diets with a considerable excess of cations were fed, urinary pH showed a characteristic pattern of widely differing values during a 24-hr period, with high values (pH ⩾ 8) for several hours of darkness, when food intake was high, declining during the day to a minimum at the end of the light period. Hyperplasia of the bladder epithelium was induced not only by feeding MSG, but also by feeding 5% of the alkalizing salt KHCO 3, both in purified diet and in stock diet. The epithelial response to an alkalizing substance was prevented by simultaneous feeding of the acidifying salt NH 4Cl. These findings indicate that the bladder changes induced by MSG are attributable to its alkalizing properties rather than to MSG per se. Moderate to severe hyperplasia of the bladder epithelium was induced also by feeding 5% NH 4Cl in purified diet, a procedure accompanied by a further lowering of urinary pH. These findings showed that hyperplasia of the bladder epithelium of rats can be induced both by acidifying and by alkalizing the urine through manipulation of the acid-base balance of the basal diet. There is thus a possibility that, in carcinogenicity studies, administration of compounds to rats in the form of a salt may lead to erroneous conclusions.

Altered glucagon release in biotin deficiency

Classical biotin deficiency in young chickens is characterized by a reduction in the activity of liver biotin-dependent enzymes which thus impairs gluconeogenesis during periods of food withdrawal. Because the normal bird maintains an elevated fasting blood glucose level, the ability of the classically biotin-deficient animal to resist changes induced by fasting has not been established. Whether the release of insulin and/or glucagon is affected by biotin deficiency has not been investigated and so determining the importance of these hormones in maintaining fasting glucose levels as well as their ability to respond to a challenge is the objective of the present study. Experimental animals (15-week-old cockerels) were fed a biotin-deficient diet for 9 weeks while control animals ( n = 8) were pair-fed biotin-supplemented diets. Before fasting, concentrations of plasma glucose, insulin, and glucagon were not different between the two groups. After 72 h of fasting basal glucose levels remained the same in both groups and concentrations of plasma insulin were equally suppressed but concentrations of glucagon were significantly elevated in biotin-deficient animals ( P<0.025). Ten minutes after an iv glucose challenge the magnitude of the increase in plasma insulin concentrations was equivalent for both groups of animals whereas the magnitude of the decline in plasma glucagon concentrations was greater for biotin-deficient birds. Twenty minutes after a protein challenge (purified casein diet) the levels of plasma glucagon in both groups were maximally increased although the concentrations remained elevated only in control animals. In conclusion the release of insulin and glucagon is not impaired in biotin-deficient animals. Fasted classically biotin-deficient animals may be able to overcome defects in gluconeogenesis induced by biotin deficiency by increasing their basal and stimulated glucagon levels.

Influence of Dietary Electrolytes on Digestive Tract pH and Acid-Base Status of Chicks

The nutritional interaction of lysine and arginine is affected by the electrolyte balance of the diet. Because the ionization and, therefore, the transport and metabolism of these amino acids may be affected by the pH of fluids in which they are dissolved, the present study was conducted to determine the effect of dietary electrolytes on the pH of the digestive tract and the acid-base status of the chicken. A purified casein diet deficient in arginine was modified by addition of either KHCO3 or CaCl2 · 2H2O at levels sufficient either to alleviate or to exacerbate the lysine-arginine antagonism. Addition of KHCO3 led to a more alkaline diet than the arginine-deficient control while CaCl2 · 2H2O resulted in a more acidic diet. Varying the electrolyte balance had little effect on digestive tract pH. The pH of the crop was depressed (P<.05) by dietary Cl−, but neither Cl− nor K+ had an effect on the pH of the proventriculus, duodenum, or middle and distal portions of the small intestine (P>.05). Dietary Cl− significantly depressed plasma bicarbonate, base excess, and PCO2 (P<.05) but did not significantly decrease plasma pH (P>.05). These same acid-base parameters were unaffected by addition of K+ to the control diet. It is concluded that variations in dietary electrolytes affect the acid-base balance of the chicken and alter the pH of the crop. However, the pH of the digestive tract from the proventriculus to the distal small intestine is unaffected. It is unlikely that the influence of electrolytes on the lysinearginine antagonism can be attributed directly to altered pH of blood or intestinal contents.

Phytohemagglutinin derived from red kidney bean (Phaseolus vulgaris): A cause for intestinal malabsorption associated with bacterial overgrowth in the rat

Plant lectins or carbohydrate binding proteins interact with membrane receptors on cellular surfaces but their antinutritional effects are poorly defined. Studies were conducted to determine the effects of phytohemaglutinin, a lectin derived from raw red kidney bean (Phaseolus vulgaris), on small intestinal absorptive function and morphology, and on the intestinal microflora. Phytohemagglutinin was isolated in purified form by thyroglobulin-sepharose 4B affinity chromatography. Red kidney bean and Phytohemagglutinin (6% and 0.5%, respectively, of dietary protein) were fed in a purified casein diet to weanling rats for up to 21 days. Weight loss, associated with malabsorption of lipid, nitrogen, and vitamin B12, developed in comparison with animals pair-fed isonitrogenous casein diets. Antinutritional effects of red kidney bean were reversible on reinstitution of a purified casein diet. An increase in bacterial colonization of the jejunum and ileum occurred in red kidney bean- and phytohemagglutinin-fed animals. When antibiotics were included in the diet, malabsorption of [3H]triolein and 57Co-vitamin B12 in red kidney bean-fed animals was partially reversed and, in germ-free animals, purified phytohemagglutinin had no demonstrable antinutritional effect. Mucosal disaccharidase activity was reduced in red kidney bean- and phytohemagglutinin-fed animals, but intestinal mucosal morphology was unchanged. Dietary administration of phytohemagglutinin, alone or as a component of red kidney bean, caused intestinal dysfunction, which was associated with, and dependent upon, small intestinal bacterial overgrowth. Adherence of enteric bacteria to the mucosal surface was enhanced by phytohemagglutinin which may have facilitated small intestinal bacterial overgrowth.

Growth responses of cherry salmon Oncorhynchus masou and amago salmon O. rhodurus fry fed purified casein diets supplemented with amino acids.

Feeding experiments were carried out to examine the supplemental effect of crystalline amino acids to casein diets on the growth of cherry salmon Oncorhynchus masou and amago salmon O. rhodurs fry. The essential amino acid patterns of eyed egg and whole body protein of cherry salmon were used as references. The following four diets were given to both groups for six weeks; a casein diet without crystalline amino acid (Diet 1), a casein diet supplemented with crystalline amino acids to simulate the essential amino acid ratio (A/E ratio) of the eyed egg protein (Diet 2), a casein diet supplemented with crystalline amino acids to simulate the A/E ratio of the whole body protein (Diet 3), and a white fish meal diet (Diet 4). Both species showed essentially the same responses to the dietary treatments and their growth responses were as follows Diet 3>Diet 2>Diet 1>Diet 4. The groups fed on Diet 3 showed significantly higher daily growth rates than those fed on Diet 1, whereas daily growth rates between Diet 2 group and Diet 1 group were not significantly different. The highest feed effciency and protein effciency ratio were obtained in the groups fed on Diet 3. Fishes fed on Diet 4 showed the highest daily feed consumption rates, but the daily growth rates and the feed effciencies were the poorest compared to all the other dietary groups.

Magnesium Requirement of Fingerling Channel Catfish and Signs of Magnesium Deficiency

Purified casein diets with and without supplemental magnesium were fed to fingerling channel catfish (Ictalurus punctatus) in order to establish the essentiality of this mineral. Fish fed the basal diet containing 0.004% magnesium developed deficiency signs such as poor growth, anorexia, sluggishness, muscle flaccidity and high mortality. After 3 weeks, two groups of fish fed the basal diet were converted to the supplemental diet containing 0.057% magnesium. Deficiency signs in these fish were alleviated almost immediately. In a second experiment, graded levels of magnesium sulfate were added to casein-based diets and fed to channel catfish fingerlings to determine their dietary requirement for magnesium. Results indicated that a minimum magnesium level of 0.04% of the dry diet was required to maintain normal growth, serum and bone magnesium levels in channel catfish fingerlings.channel catfish magnesium requirement magnesium deficiency

Growth response of Tilapia zillii fingerlings fed isocaloric diets with variable protein levels

Six purified casein diets within a range of 21–53% crude protein were fed for 3 weeks to young tilapia ( Tilapia zillii) to determine the optimum protein requirement and protein: energy ratio for growth. Growth rate increased proportionally to protein level of the diet to an incorporation rate of about 35%. Beyond this a gradual retardation in growth rate was observed. The diet containing about 30% crude protein with a protein: energy ( P E ) ratio of 81, however, appeared to be more efficiently utilized by the fish in terms of protein deposition and energy retention than diets with higher levels of crude protein. These results indicate that Tilapia zillii requires about 35% protein in the diet for optimum growth while 30% for the maximum bodily protein deposition when casein is used as the sole source of protein. All six diets, however, showed an excellent feed conversion. Protein efficiency ratio (PER) decreased with the increase in protein in the diet.

Inhibitory Effect of Dietary Arginine on Growth of Ehrlich Ascites Tumor Cells in Mice

The effect of dietary L-arginine on the growth and development of transplantable Ehrlich Ascites tumor cells was examined. Growth of tumor bearing mice was significantly inhibited by feeding a purified casein diet supplemented with 5% arginine. This diet significantly reduced the total number of free tumor cells growing in the peritoneal cavity of mice. Total free tumor cell RNA, DNA, and protein were also significantly reduced. Supplemental arginine approximately doubled the length of time for 50% death of tumor bearing mice. Arginine did not alter respiration as measured by glucose or citrate oxidation. Varying the concentration of supplemental dietary arginine revealed that 3% arginine also significantly retarded the growth of Ehrlich Ascites Tumor Cells. Tumor ornithine decarboxylase activities were significantly reduced by dietary arginine supplementation. Supplemental dietary arginine at 3 or 5% did not significantly affect the growth of non-tumor bearing mice. Dietary arginine may play a critical role in growth of normal as well as neoplastic tissue.

Nutritional effects of field bean (Vicia fabaL.) proteinase inhibitors fed to rats

1. Weanling rats were fed on purified-casein diets containing active and inactive (autoclaved) field bean (Vicia faba L.) proteinase inhibitors (PI) at levels of 1.25, 2.5, 5.0 and 10 g/kg. Diets containing raw- and autoclaved-field-bean meal (FBM) were also given. The body-weight gain, protein efficiency ratio (PER); i.e. the ratio of the live weight gain in g/g of protein consumed and apparent nitrogen digestibility were determined 7, 14 and 21 d after the start of the trial. 2. Significant growth depression (P less than 0.001) was observed in rats given diets containing 2.5 g/kg PI (27--35%). In rats fed on raw FBM growth depression was severe after 7 d (57%). 3. Food intake was depressed at PI inclusion levels of 5 g/kg and higher between 14 and 21 d. 4. PER was depressed significanlty (33-44%) in rats given diets containing the active PI at all levels after 7 d. The protein utilization of all casein diets was higher than that of the FBM diets. 5. Apparent N digestibility was depressed in rats fed on diets containing 10 g/kg PI by 9 and 7% at 14 and 21 d respectively. The N digestibility of both raw and heated FBM was similar at approximately 84%. 6. It was concluded that the PI are not the main factors responsible for the growth depression observed when raw FBM is fed to rats.

EFFECTS OF INORGANIC SULFATE SUPPLEMENTS ON THE GROWTH OF RATS FED SULFUR AMINO ACID-DEFICIENT DIETS

Rats were fed sulfur amino acid-deficient diets supplemented with inorganic sulfate to test whether sulfate spared sulfur amino acids for growth. The dietary protein sources used were lupin kernels, alfalfa leaf protein concentrate, commercial casein, or purified casein; 10% protein diets were supplemented with sodium sulfate (1.5 g/kg) and/or various levels of DL-methionine. Sulfate did not improve weight gain or protein efficiency ratio when added to diets containing lupin kernels, alfalfa leaf protein concentrate, or commercial casein. The lack of response was probably due to the relatively high intrinsic non-protein sulfur or inorganic sulfate contents of the diets. When the intrinsic sulfate level was reduced to 0.003% as in the purified casein diet, added sulfate significantly improved weight gain and protein efficiency ratio.

TAURINE IN THE DEVELOPING KITTEN: NUTRITIONAL IMPORTANCE

Kittens fed a purified-casein diet immediately after weaning develop retinal degeneration and blindness unless supplemented with taurine (tau). Supplementation with tau precursors (methionine, cystine or inorganic sulfate) does not prevent this. In contrast, the amount of tau in the form of taurocholate in these kittens does not change appreciably and tau concentration in brain tissue is more severely depleted than retina, but without apparent behavioral or pathological change. Apparently the most important function of tau in kittens is bile acid conjugation and this function is maintained at the expense of tissues. Second in importance seems to be retinal function but the kitten is unable to maintain normal retinal tau conc because of: 1) its postnatal rapid rate of increase in retinal tau conc, 2) the high tau conc in cat retina, 3) the low rate of tau synthesis in cat, 4) the rapid growth rate of kitten, 5) the inability of cat to convert from tau conjugation to predominantly glycine conjugation of bile acids (as the human infant does). These changes are likely to be more severe if the kitten is fed the synthetic diet immediately after birth, for cat milk contains a high concentration of tau and therefore can minimize the deficiency. The relevance of these results to the human infant will be discussed in light of the limited ability of man to synthesize tau, the low conc of tau in cow milk and formulas derived from it, and the high cone of tau in human milk.

Effect of Dietary Ascorbic Acid on Iron Utilization in the Growing Chick

Day-old male broiler chicks were fed for three weeks a purified casein diet with the addition of different levels of iron and ascorbic acid. Dietary ascorbic acid fed at 0.4% increased the hemoglobin concentration and total body iron retention when the diets fed were low in iron (23 p.p.m.). At 0.1% level in the diet, ascorbic acid caused an increase in total body iron retention in chicks fed diets marginal in iron (40 p.p.m.) and did not affect either parameter in chicks fed diets adequate in iron (100 p.p.m.).

The pathogenesis of hydrocephalus in newborn rats deficient in vitamin B12

ABSTRACT Richardson &amp; Hogan (1946) produced hydrocephalus in rats by feeding a purified casein diet containing all the vitamins available at that time. Almost 2% of the young from females fed the experimental diet were hydrocephalic; female rats fed the same diet supplemented with liver extract gave birth to normal young. It is now thought that this diet was marginally deficient in vitamin B12 (Newberne &amp; O’Dell, 1961). Animals which showed no gross evidence of lesions in the central nervous system had reduced maze-learning abilities as compared to animals on control diets (Whitley, O’Dell &amp; Hogan, 1951).

Comparisons of Casein and Soy Proteins upon Mineral Balance and Vitamin D2 Requirement of the Baby Pig

Comparisons were made of the effects of dietary protein source (casein versus isolated soy protein) upon growth, serum mineral level, skeletal development, mineral balance and vitamin D2 requirement of the baby pig. Purified casein diets containing zero, 50 or 100 IU of vitamin D2/kg or soy protein diets containing 50, 100, 250 or 500 IU of vitamin D2/kg were utilized. The casein diet containing 100 IU of vitamin D2/kg gave optimal values for all criteria. Using these values as standards, 50 IU of vitamin D2/kg in a casein diet resulted only in substandard serum and bone Mg concentration. Levels of vitamin D2 of 50 or 100 IU/kg in soy protein diets gave suboptimal values for many of the criteria. Only soy protein diets containing 500 IU of vitamin D2/kg produced optimal growth rate. Soy protein diets containing 250 or 500 IU of vitamin D2/kg gave optimal concentrations of serum Ca, P, Mg and alkaline phosphatase activity and bone ash. Pigs receiving soy protein diets excreted excessive amounts of fecal Ca, P and Mg resulting in decreased mineral retention and this decrease was not overcome by increasing dietary vitamin D2 levels in this study. The data indicate that the vitamin D2 requirement of the baby pig receiving purified diets containing isolated soybean protein is greater than the 100 IU/kg requirement level of casein diets and may be several times this level depending upon the criteria selected, the level of isolated soybean protein in the diet and the method of isolation of the soybean protein.

Nutrition of the Boll Weevil Larva1

Dietary requirements of the boll weevil, Anthonomus grandis Boheman, larva reared on a purified casein diet are reported. Compounds of myo-inositol are just as effective in promoting growth as free inositol. Choline is needed and cannot be replaced by betaine, carnitine, or ethanolamine. Dietary fat improves development of the larvae and permits more larvae to become adults. Sterols are indispensable for growth; cholesterol, stigmasterol, and sitosterol can all be used. Six B-vitamins found to be needed in casein diets are pantothenic acid, thiamine, riboflavin, pyridoxine, niacinamide, and folic acid. Biotin was not required. In the tests performed, antimetabolites of thiamine, biotin, and pantothenic acid did not interfere with growth. Sodium alginate, used in previous diets as a stabilizer, was found to inhibit growth.