摘要:

Syrian hamsters were fed torula yeast (TY) diets with 8 selenium (Se) supplement levels (0.0-10.0 ppm Se as sodium selenite) or casein (C) diets with 5 supplement levels (0.0-5.0 ppm Se as sodium selenite) for 25 weeks. Whole blood Se, plasma glutathione peroxidase (GSH-Px) activity and erythrocyte GSH-Px activity were measured after 5, 10, 15 and 25 weeks. At 25 weeks hematology was examined and tissue samples analyzed for Se and evaluated for histopathological lesions. While survival was not influenced by dietary Se, food consumption and body weight gain were altered in animals given TY, as those fed 0.0, 0.05 or 10.0 ppm Se consumed less diet. Weight gains at 25 weeks were highest in animals at the 0.1 ppm Se level and reduced in those given unsupplemented TY or 10.0 ppm Se supplements. Hemoglobin, hematocrit and red blood cell counts were reduced in females fed the lowest and highest Se supplements with TY diets. With both C and TY, whole blood Se rose with increasing dietary Se and in the case of TY, Se was elevated with each feeding increment, except between the 0.05 and 0.1 ppm or the 0.25 and 0.5 ppm levels. Plasma GSH-Px increased with rising Se up to 10 ppm, and erythrocyte GSH-Px activity increased up to 5 ppm Se. Erythrocyte GSH-Px values were higher in animals fed C diets. Histopathological observations were normal at all Se levels. Syrian hamsters tolerated dietary Se from 0.05 to 5.0 ppm Se for 25 weeks of observation without detrimental effects.

ISSN:0250-6807    

DOI:10.1159/000176627

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Experiments were conducted to examine the potential utilization of dietary urea by rainbow trout. A control diet and two diets supplemented with 1 and 3 % of urea were fed to fish. Postprandial levels of urea and ammonia in blood plasma, and postprandial excretion of these metabolites were followed during 24 h. Apparent digestibility of urea in rainbow trout was very high ( > 98%). Maximum values of urea levels in plasma were reached 6 h (32.3 ± 10.2 µg/ml) after a meal in the control fish and respectively 6 h (83.4 ± 18.4 µg/ml) and 8 h (250.3 ± 96.1 µg/ml) after a meal in trout fed 1 and 3% urea diets. Peaks of urea excretion rates appeared 7–9 h after meal, coinciding with the highest circulating urea concentration. Total daily urea excretion amounted to 5.53, 10.43 and 33.80 mg urea N/100 mg N intake in trout fed the control, 1 and 3 % urea diets, respectively. It is concluded that the dietary urea is readily absorbed in the digestive tract of trout but is totally excreted thus leading to no beneficial effect on nitrogen balance. This excretion of urea also takes place passively without any increase in energy

ISSN:0250-6807    

DOI:10.1159/000176628

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The relative contributions have been determined of taurine derived from the mother in utero, via milk during nursing, and from endogenous biosynthesis to the total taurine content of the rat pup between birth and weaning. At birth, 32% of the taurine in the pup has been biosynthesized, and this proportion rises to 83% by day 20 of life. At birth, 67% has been derived from the mother in utero, and by day 20 this has fallen to 4% of the total. This maternal taurine is lost with a half-life of 16 days. There is wide variation in the turnover from different tissues, the pancreas having a half-life of 7 days, and the brain 50 days. However, the amount of maternal taurine in the brain actually increases by 38% over the first 8 days of life. By day 20, 13% of the taurine content of the pup has been obtained from the milk. Taurine turnover in the suckling pup differs from turnover after weaning in that whole-body turnover from the suckling rat is not slower than exchange between organs. In other words, tissues are not in kinetic equilibrium. After animals are weaned, regardless of the taurine content of the diet, taurine is interchanged between organs faster than it is excreted from the animal.

ISSN:0250-6807    

DOI:10.1159/000176629

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Replacement of soy protein by casein in the cholesterol-free, semipurified diet of rabbits caused hypercholesterolemia within 7 days. After 36 days, the serum of casein-fed rabbits displayed elevated levels of free and esterified cholesterol and phospholipids, but not of triglycerides. Most of the excess of serum cholesterol in the casein group was localized in the LDL fraction, but there were marked variations in the density profile of the serum lipoproteins between individual rabbits. Dietary casein induced an increased content in liver of free and esterified cholesterol, but not of phospholipids and triglycerides. The molar ratio of free to esterified cholesterol in the liver was decreased by casein. In contrast, feeding casein resulted in an increase of this ratio in the serum.

ISSN:0250-6807    

DOI:10.1159/000176630

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The effect of 50 ppm F as sodium fluoride in the drinking water for 15 weeks on bone, plasma, and urinary cAMP levels, and on bone alkaline and acid phosphatase activities have been investigated in rats stressed with calcium deficiency and/or lactation, as well as in normal rats. Lactation and calcium deficiency (0.1 % calcium in diet) was found to cause an increase in urinary cAMP excretion but did not cause any significant alteration in plasma and bone cAMP levels. Bone alkaline and acid phosphatase activities were lower in lactating rats furnished the 1.0% calcium diet when compared to the nonlactating controls. Fluoride had no effect on all parameters studied.

ISSN:0250-6807    

DOI:10.1159/000176631

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The effect of semipurified diets containing either casein or soy protein on serum lipids, lipoprotein composition and liver cholesterol was studied in genetically obese Zucker rats. The ingestion of a cholesterol-enriched semipurified diet containing casein resulted in elevated levels of serum cholesterol and phospholipids compared to the feeding of a soy protein diet. No differences in serum triglycerides were observed. Differences in serum cholesterol and phospholipids were mainly reflected in the very low density lipoproteins and low density lipoproteins and to a minor extent in the high density lipoproteins. Liver cholesterol paralleled the levels of cholesterol in the serum, the rats fed casein exhibited markedly higher levels of liver cholesterol than those fed soy protein. Furthermore, the rats fed casein also had enlarged livers. Thus, this study clearly shows the differential cholesterolemic effect of dietary casein and soy protein in genetically obese Zucker rats.

ISSN:0250-6807    

DOI:10.1159/000176632

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The effect of dietary protein and fiber on growth and metabolic parameters in blood serum, liver and kidney were determined in a 2 × 5 factorial experiment involving 40 Sprague-Dawley rats. Treatment variables were two dietary protein levels (16 and 24%) and five acid detergent fiber levels (6, 10, 16, 24 and 34%). No difference in growth rate of rats was found due to varying levels of either protein or fiber in the diet. Increasing the dietary protein level from 16 to 24% resulted in an 18.5% reduction in blood cholesterol. The dietary treatment containing 16 % fiber influenced most metabolic parameters examined, including blood serum cholesterol, liver cholesterol and total lipid content in liver and kidney. Rats receiving the diet containing 16% fiber had the highest serum cholesterol (88.9 mg/dl) and the lowest liver cholesterol (4.4 mg/g) as compared with other fiber groups

ISSN:0250-6807    

DOI:10.1159/000176633

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The lipase activity of bacterial species isolated from the caecum of conventional rabbits was studied by means of two groups of tests: (1) bacteriologic isolation and an identification of nine aerobic and anaerobic clones and (2) incubation of each of these clones in the appropriate medium in the presence of labelled triolein (oleyl 1–14C), a biochemical analysis of the radioactivity of the fractions obtained. The main results can be expressed in the following way: maximum hydrolysis of glycerides is achieved by two species: Bacillus lichenifor-mis and Clostridium sporogenes. The reaction is proportional to the incubation time for incubations of less than 8 h. The release of fatty acids is concomitant to the synthesis of phospholipids and of fatty acid methyl esters.

ISSN:0250-6807    

DOI:10.1159/000176634

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

In the young rabbit, immunoreactive serum insulin (IRI) significantly rises during the first 5 min after suckling and then 20–60 min later, at which time the maximum level is reached. Blood glucose levels remain stable, blood ketone bodies increase 2.7 times and the liver glycogen levels decrease. Replacement of maternal milk by an equal volume of 0.9% NaCl, 2% lactose or 3.5 % glycerol does not induce any change in IRI. IRI significantly rises if solutions of bovine milk proteins or skimmed rabbit’s milk are administered. This effect is quickened and strengthened by the addition of coconut oil or lipids of rabbit’s milk whereas sunflower oil is ineffective. It is suggested that medium-chain fatty acids, major components of rabbit’s milk lipids, play an important role in the regulation of insulin secretion in the young

ISSN:0250-6807    

DOI:10.1159/000176635

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The effects of a diet consisting of 10% medium-chain triglycerides (C8:0, C10:0) or 10% homogeneous triglycerides of 6- to 14-carbon chain saturated fatty acids on cholesterol turnover processes were studied in rats using the isotope equilibrium method. Cholesterol absorption was not significantly affected by the type of dietary fatty acid ingested. In contrast, lengthening of the fatty acid chain caused a moderate increase in the rates of cholesterol secretion (internal and external) and of transformation into bile acids. Thus, cholesterol synthesis was 80% higher in rats fed trimyristin (25.7 mg/day) than in those receiving tricaproin (14.6 mg/day). This increase seems essentially due to stimulated liver cholesterogenesis, as shown by in vivo incorporation of 14C-acetate.

ISSN:0250-6807    

DOI:10.1159/000176636

出版商:S. Karger AG    

年代:1983

数据来源: Karger