scholarly journals Influence of dietary fish proteins on plasma and liver cholesterol concentrations in rats

1993 ◽  
Vol 69 (3) ◽  
pp. 767-777 ◽  
Author(s):  
Xizhong Zhang ◽  
Anton C. Beynen
Keyword(s):  
Dietary Protein ◽  
Cholesterol Metabolism ◽  
Plasma Cholesterol ◽  
Protein A ◽  
Soya Bean ◽  
Female Rats ◽  
Liver Cholesterol ◽  
Dietary Fish ◽  
Fish Proteins ◽  
Bean Protein

The effects of amount and type of dietary fish proteins on plasma and liver cholesterol concentrations were evaluated in female rats. The isonitrogenous diets used contained 10 g cholesterol/kg and were carefully balanced for residual fat, cholesterol, Ca, Mg and P in the protein preparations. Cod meal, soya-bean protein or casein was incorporated into the diets as the only source of dietary protein a t three levels: either 24,48 or 72 g N/kg diet. Extra protein was added to the diet at the expense of the glucose component. In a second experiment soya-bean protein, casein, cod meal, whiting meal or plaice meal was added to the diet at a level of 24 g N/kg. When compared with casein, cod meal and soya-bean protein decreased plasma and liver cholesterol concentrations. A further cholesterol-lowering effect was achieved by increasing the proportion of either soya-bean protein or cod meal in the diet. Substitution of casein for glucose did not influence plasma and liver cholesterol concentrations. Plaice meal in the diet produced lower group mean plasma cholesterol concentrations than did whiting meal. In rats fed on the diet containing plaice meal, liver cholesterol concentrations were significantly lower than those in their counterparts fed on either cod meal or whiting meal. The present study demonstrates that different fish proteins in the diet have different effects on cholesterol metabolism and that the cholesterol-influencing properties of cod meal can be enhanced by the incorporation of higher proportions of this protein in the diet.

scholarly journals Dietary animal proteins and cholesterol metabolism in rabbits

1990 ◽  
Vol 64 (2) ◽  
pp. 473-485 ◽  
Author(s):  
Maria R. Lovati ◽  
Clive E. West ◽  
Cesare R. Sirtori ◽  
Anton C. Beynen
Keyword(s):  
Bile Acid ◽  
Whey Protein ◽  
Serum Cholesterol ◽  
Cholesterol Metabolism ◽  
Soya Bean ◽  
Liver Cholesterol ◽  
Fish Protein ◽  
High Background ◽  
Neutral Steroid ◽  
Bean Protein

The effect in rabbits of giving isonitrogenous purified diets containing casein, ovalbumin, fish protein, milk-whey protein and soya-bean protein were compared. The diets were balanced for cholesterol and for the amount and type of fat. When incorporated into low-cholesterol diets (0.8 g cholesterol/kg), casein, ovalbumin and soya-bean protein produced similar levels of serum cholesterol. With a high background of dietary cholesterol (1.5 g/kg), serum cholesterol concentrations increased with soya-bean protein, whey protein, casein and fish protein, in that order. Thus, the hypercholesterolaemic effect of casein in carefully balanced diets was only seen against a high-cholesterol background. The development of hypercholesterolaemia produced by giving fish protein was different from that produced by casein. First, less cholesterol accumulated in the very-low-density-lipoprotein fractions and more in the lipoproteins of higher density with fish protein than with casein. Second, fish protein, unlike casein, did not increase liver cholesterol. Third, transfer of rabbits from a diet containing soya-bean protein to one containing casein resulted in an immediate marked depression in neutral steroid and bile acid excretion in faeces. However, when rabbits were fed on the diet with fish protein after the diet with soya-bean protein, there was no significant depression in neutral steroid output and the depression in bile acid output was delayed. The present study suggests that different animal proteins cause hypercholesterolaemia by different mechanisms.

Effects of graded levels of soya-bean protein on endogenous ileal lysine loss and amino acid digestibility in growing pigs

2005 ◽  
Vol 81 (2) ◽  
pp. 257-264 ◽  
Author(s):  
H. L. Zhang ◽  
S. Y. Qiao ◽  
X. J. Chen ◽  
X. Wang ◽  
J. J. Xing ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protein Level ◽  
Protein A ◽  
Latin Square ◽  
Protein Product ◽  
Soya Bean ◽  
Growing Pigs ◽  
Protein Levels ◽  
Sigmoid Curve ◽  
Bean Protein

AbstractThis experiment investigated the effects of feeding graded levels of a soya-bean protein product (HP300, Hamlet Protein A/S Company, Denmark) on endogenous ileal lysine loss, apparent ileal amino acid digestibility, standardized true ileal amino acid digestibility determined using the protein-free (PF) method, and real ileal amino acid digestibility determined using the homoarginine (HA) method. The soya-bean protein product was obtained by purifying and defattening soya bean via a proprietary microbial process that decreased the level of trypsin inhibitors and other anti-nutritional factors in soya bean. Six barrows, with an initial body weight of 37·4 ± 1·3 kg, were surgically fitted with simple T-cannulae at the distal ileum and offered six maize-starch-based diets according to a 6 × 6 Latin-square design. The six diets were formulated to provide 0, 50, 100, 150, 200, or 250 g crude protein (CP) per kg by dietary inclusion of 0, 90, 182, 274, 367 or 460 g/kg of soya-bean protein. Five kg of soya-bean protein product was guanidinated in order to estimate endogenous amino acid flow and real ileal amino acid digestibility. Chromium III oxide (5 g/kg) was included in the non-guanidinated diets while dysprosium chloride (0·1 g/kg) was included in the guanidinated diets as an indigestible marker. The experimental periods lasted 8 days. On day 6 of each period, ileal digesta was collected for 24 h to determine apparent and standardized true ileal amino acid digestibility of the non-guanidinated diets. At 08:00 h on day 8, the pigs were given a single meal of the diets containing guanidinated protein and their ileal digesta was collected for 24 h in order to determine the total HA flow and the real ileal digestibility of lysine. Endogenous ileal lysine flow appeared to follow a sigmoid curve starting at about 370 mg/kg dry matter (DM) intake for pigs given the PF diet and continuing asymptotically to about 750 mg/kg DM intake when the inclusion level of the soya-bean protein product was increased to 182 g/kg (100 g/kg of CP). The endogenous ileal lysine flow for pigs given the PF diet was similar (P > 0·05) to that of pigs given 90 g/kg soya-bean protein (50 g/kg of CP) and it increased sharply (P < 0·05) as the level of soya-bean protein increased from 90 to 182 g/kg (50 to 100 g/kg of CP). Thereafter, it was relatively constant (P > 0·05). With an increase in soya-bean protein, there was a quadratic increase (P < 0·01) in the apparent ileal digestibilities for all amino acids except valine and phenylalanine. Standardized true ileal amino acid digestibility decreased (P < 0·05) with an increase in soya-bean protein level. However, real ileal amino acid digestibilities were not influenced (P > 0·05) by soya-bean protein in the diet at levels between 90 and 367 g/kg (50 and 200 g/kg of CP). In conclusion, endogenous ileal lysine flow was not constant and was significantly affected by soya-bean protein level. The results of this study suggest that standardized true ileal amino acid digestibility should be measured between 100 and 200 g/kg of CP (182 and 367 g/kg soya-bean protein) while real ileal amino acid digestibility is unaffected by protein levels between 50 and 200 g/kg of CP (90 and 367 g/kg soya-bean protein).

scholarly journals Effect of dietary methionine on plasma and liver cholesterol concentrations in rats and expression of hepatic genes involved in cholesterol metabolism

2006 ◽  
Vol 95 (5) ◽  
pp. 879-888 ◽  
Author(s):  
F. Hirche ◽  
A. Schröder ◽  
B. Knoth ◽  
G. I. Stangl ◽  
K. Eder
Keyword(s):  
Cholesterol Synthesis ◽  
Cholesterol Metabolism ◽  
Plasma Cholesterol ◽  
Rat Hepatocytes ◽  
Liver Cholesterol ◽  
Isolated Rat Hepatocytes ◽  
Hepatic Expression ◽  
Hepatic Cholesterol Synthesis ◽  
Methionine Concentration ◽  
Ldl Uptake

Methionine has been shown to increase plasma cholesterol in animals. In the present study, mechanisms were investigated by which methionine could alter cholesterol metabolism. In the first experiment, forty growing rats were fed four casein-based diets differing in methionine content (2·6, 3·5, 4·5 or 6·0 g/kg) for 14 d. In the second experiment, isolated rat hepatocytes were incubated in media supplemented with 50, 100 or 200 μmol/l methionine. Dietary methionine tended to increase plasma homocysteine concentrations in the rats (P=0·058). A weak positive correlation between circulating homocysteine and plasma cholesterol was observed (R20·27, P<0·01). Rats fed 3·5 g/kg or more of methionine had higher concentrations of cholesterol in their plasma, in lipoprotein fractions of density (ρ kg/l) 1·006 < ρ<, 1·063 and ρ>. 1·063, and in liver than rats fed 2·6 g/kg methionine. Rats fed 6 g/kg methionine had a higher hepatic expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase and cholesterol-7α-hydroxylase than rats fed less methionine. The phosphatidylcholine:phosphatidylethanolamine ratio in rat liver increased with rising dietary methionine concentration; the relative mRNA concentrations of phosphatidylethanolamine N-methyltransferase and cystathionine β-synthase remained unaffected. Hepatocytes incubated in media supplemented with 100 or 200 μmol/l methionine had a higher cholesterol synthesis than hepatocytes incubated in a medium supplemented with 50μmol/l methionine; the LDL uptake in hepatocytes was independent of the methionine concentration of the medium. In conclusion, the present study suggests that dietary methionine induces hypercholesterolaemia at least in part via an enhanced hepatic cholesterol synthesis.

scholarly journals A comparison of the effects of soya-bean protein and casein on bile composition, cholelithiasis and serum lipoprotein lipids in the vervet monkey (Cercopithecus aethiops)

1987 ◽  
Vol 58 (2) ◽  
pp. 257-263 ◽  
Author(s):  
K. Jaskiewicz ◽  
M. J. Weight ◽  
K. J. Christopher ◽  
A. J. S. Benadé ◽  
D. Kritchevsky
Keyword(s):  
Plasma Lipids ◽  
Plasma Cholesterol ◽  
Soya Bean ◽  
Protein Source ◽  
Vervet Monkeys ◽  
Biopsy Material ◽  
Bile Composition ◽  
Cholesterol Levels ◽  
Significant Difference ◽  
Bean Protein

1. Two groups of vervet monkeys (Cercopithecus uethiops) were fed on high-cholesterol diets which differed only with respect to the protein source. In one group casein was the only protein source, while the other group received only soya-bean protein.2. Samples of blood, bile and liver biopsy material were collected at the commencement of the study and at 3-monthly intervals until termination 12 months later.3. At the end of the experimental period all the animals (n19) had high plasma cholesterol levels and had developed pigment gallstones, the compositions and weights of which were not related to the protein source or to plasma cholesterol levels. Gallstone weight was related to the presence of acidic and sulphated mucins in gallbladder mucosa. We were also unable to confirm the hypocholesterolaemic effect of soya-bean protein which has been demonstrated previously in rhesus monkeys and hamsters. Bile composition, and plasma lipids did not differ significantly between the casein-fed and soya-bean fed animals. Lithogenic index was below 1 for both groups and did not differ significantly between the two groups.4. No significant difference was found in the severity ofcholelithiasis between the casein-fed and the soya-bean-fed animals.

scholarly journals The importance of the non-protein components of the diet in the plasma cholesterol response of rabbits to casein

1987 ◽  
Vol 57 (1) ◽  
pp. 27-33 ◽  
Author(s):  
S. Samman ◽  
D. C. K. Roberts
Keyword(s):  
Plasma Cholesterol ◽  
Zinc Content ◽  
Similar Rate ◽  
Protein Isolate ◽  
Soya Bean ◽  
Liver Cholesterol ◽  
Zn Content ◽  
Protein Components ◽  
Mineral Interaction ◽  
Cu And Zn

1. To characterize further the effect of protein-mineral interaction on plasma cholesterol, four groups of rabbits were placed on cholesterol-free, semi-purified diets for 12 weeks. The diets were similar in proximate composition with either casein or soya-bean protein isolate as the protein source (250 g/kg).2. The dietary zinc content of the casein diets was increased to 22 mg/kg to equal that of the soya-bean diets. The copper content was set at 2 and 6 mg/kg. There were no differences in weight gain; all animals grew at a similar rate.3. When the dietary Zn content was equalized, the plasma and liver cholesterol responses were similar regardless of the source of protein.4. Differences in liver Cu and Zn were observed. As dietary Cu increased, Cu decreased and Zn increased in the liver. Hepatic Zn was also higher in soya-bean-fed than in casein-fed animals.5. No effects on plasma Cu and Zn were seen.6. The addition of Zn to the casein diet resulted in a similar plasma cholesterol to that of animals fed on the soya-bean diet, suggesting that casein-induced hypercholesterolaemia is due to a marginal Zn intake.

scholarly journals The effect of dietary protein source and saponins on serum lipids and the excretion of bile acids and neutral sterols in rabbits

1981 ◽  
Vol 46 (3) ◽  
pp. 421-430 ◽  
Author(s):  
Chitra Pathirana ◽  
M. J. Gibney ◽  
T. G. Taylor
Keyword(s):  
Dietary Protein ◽  
Serum Lipids ◽  
Milk Protein ◽  
Soya Bean ◽  
Protein Source ◽  
Plant Proteins ◽  
Lower Serum ◽  
Neutral Sterols ◽  
Dietary Protein Source ◽  
Bean Protein

1. Four groups of six rabbits were given purified diets in which the dietary variables were protein source (isolated soya-bean protein or cow's-milk protein) with or without saponin supplementation (10 g/kg).2. Rabbits given soya-based diets showed significantly lower serum concentrations of triglyceride and cholesterol (P < 0·01). The latter changes were confined to the cholesterol fractions of β-lipoproteins.3. These changes in serum cholesterol were associated with a significantly increased excretion of acid and neutral sterols in animals given soya-bean protein.4. There was no evidence to suggest that the effect of dietary protein source on serum lipids and the excretion of total and individual sterols was influenced by saponin supplementation.5. These results do not support the hypothesis that the hypocholesterolaemia associated with plant proteins is due to the presence of saponins.

scholarly journals Effect of dietary protein from proso millet on the plasma cholesterol metabolism in rats.

1990 ◽  
Vol 54 (1) ◽  
pp. 229-230 ◽  
Author(s):  
Naoyuki NISHIZAWA ◽  
Mihoko OIKAWA ◽  
Shin-ichi HAREYAMA
Keyword(s):  
Dietary Protein ◽  
Cholesterol Metabolism ◽  
Plasma Cholesterol ◽  
Proso Millet

scholarly journals The importance of the non-protein components of the diet in the plasma cholesterol response of rabbits to casein

1985 ◽  
Vol 54 (1) ◽  
pp. 87-94 ◽  
Author(s):  
E. C. Allotta ◽  
S. Samman ◽  
D. C. K. Roberts
Keyword(s):  
Trace Elements ◽  
Plasma Cholesterol ◽  
Young Male ◽  
Protein Isolate ◽  
Soya Bean ◽  
Casein Diet ◽  
The Mean ◽  
Protein Components ◽  
Mean Concentration ◽  
Bean Protein

1. To characterize the hypercholesterolaemic effect of casein further, four groups of young male rabbits in two separate experiments were placed on cholesterol-free semi-purified diets for 12 weeks. The diets were similar in composition, with either casein or soya-bean-protein isolate providing the protein source (250 g/kg). In two of these diets the salt mix was reduced by 45% (normally 40 g/kg) and replaced by potassium bicarbonate.2. Growth was unaffected by these alterations in dietary salts except for one group given the soya-bean-reduced-salts diet.3. The mean concentrations of plasma cholesterol were significantly higher in all casein-fed groups as compared with their soya-bean-fed counterparts but the response was much greater in those given the casein—reduced-salts diet.4. Contrary to expectations, analysis of the diets showed the zinc and copper concentrations of the casein diets to be less than those of the soya-bean diets. This was due to the greater concentrations of Cu (threefold) and Zn (twofold) in the soya-bean-protein isolate compared with casein.5. The mean concentration of Zn in fur was significantly decreased in casein-fed rabbits and these animals also excreted less Zn but more Cu in their urine than those given the casein—reduced-salts diet.6. The rabbits given the casein diet with the least salt mix showed the greatest degree of hypercholesterolaemia, suggesting an interaction between trace elements and the casein effect.

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