scholarly journals Digestibilities of casein and soya-bean protein in relation to their effects on serum cholesterol in rabbits

1985 ◽  
Vol 54 (2) ◽  
pp. 355-366 ◽  
Author(s):  
Christopher J. H. Woodward ◽  
Kenneth K. Carroll
Keyword(s):  
Heat Treatment ◽  
Serum Cholesterol ◽  
Soya Bean ◽  
Pancreatic Enzymes ◽  
Alkaline Ph ◽  
Acid Ph ◽  
Ph Dependent ◽  
Low Solubility ◽  
Bean Protein

1. Diets containing isolated soya-bean protein induce lower levels of serum cholesterol in animals than diets containing casein. Experiments were conducted to investigate whether differences in digestibility of the proteins might explain this effect.2. At pH 8 with pancreatic enzymes or intestinal peptidase, soya-bean protein was hydrolysed in vitro much less rapidly than casein. However, with pepsin (EC3. 4. 23. 1) at acid pH, soya-bean protein was hydrolysed more rapidly than casein.3. These differences in digestibility may be due to pH-dependent changes in solubility of the proteins. Casein and soya-bean protein were most soluble at alkaline and acid pH respectively.4. Heat treatment of the proteins resulted in lower solubilities and digestibilities. Sonication of soya-bean protein at pH 7.8 increased solubility but only slightly raised digestibility.5. When fed to rabbits, enzymically hydrolysed soya-bean protein induced a 2.3-fold higher concentration of serum cholesterol than did intact soya-bean protein. The hypocholesterolaemic effect of soya-bean protein may be partly attributable to its low solubility and digestibility at alkaline pH.

scholarly journals PSVII-35 Late-Breaking Abstract: Microwave heat treatment feed effect on ruminal degradability and intestinal protein digestibility - a brief review

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 342-343
Author(s):  
Md Safiqur Rahaman Shishir ◽  
Muhammad Jamal Khan ◽  
Hassan Khanaki ◽  
Graham Brodie ◽  
Brendan Cullen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Protein Digestibility ◽  
Soya Bean ◽  
Canola Meal ◽  
Canola Seed ◽  
Intestinal Protein ◽  
Bean Meal ◽  
Ruminal Degradability ◽  
Soya Bean Meal

Abstract Rumen degradability of crude protein (CP) of feed is a major factor that determines the utilization of CP in ruminant production. This study briefly reviewed the findings from six international studies of microwave (MW) heat treatment effect on feed CP rumen degradability and intestinal CP digestibility. Six in vitro studies of concentrate feed (canola seed, canola meal, soya bean meal, cottonseed meal, corn, and barley) showed a decrease in effective rumen degradability of dry matter and protein by 4–40% and 17–40%, respectively compared to control group (untreated concentrate feed). Among the six studies, four studies identified the MW heat treatment effect on intestinal protein digestibility. Due to MW heat treatment, canola seed, canola meal, soya bean meal, and cottonseed meal showed an increase in intestinal CP digestibility by 17%, 20%, 21%, and 19%, respectively. Overall the briefly reviewed studies showed that, MW heat treatment substantially reduced feed CP ruminal degradability and increased in vitro CP digestibility of ruminally undegraded CP.

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.

scholarly journals Effect of soya-bean protein on meat iron solubility and absorption in rats

1986 ◽  
Vol 55 (2) ◽  
pp. 419-426 ◽  
Author(s):  
G. O. Latunde-Dada ◽  
R. J. Neale
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
In Vitro Digestion ◽  
Soya Bean ◽  
Chicken Meat ◽  
Iron Solubility ◽  
Bean Protein

1. Soya-bean proteins were used to replace 30 and 50% of the protein from 59Fe-labelled pigeon (Columbn L.) and chicken meat, and the solubility of the meat 59Fe in vitro and its absorption in vivo in rats in the presence and absence of soya-bean proteins were measured.2. Replacement of part of the chicken meat by soya-bean proteins reduced 59Fe solubility from chicken meat at all stages during simulated in vitro digestion.3. 59Fe absorption from 59Fe-labelled chicken meat when given to both Fe-replete and Fe-deficient rats was reduced in the presence of soya-bean proteins but was unaffected by the presence of casein or bovine serum albumin. 59Fe-absorption from pigeon meat in the presence of soya-bean proteins was not reduced to the same extent as that from chicken meat.4. There was no significant effect of soya-bean proteins on 59Fe-labelled haemoglobin Fe absorption in vivo in Fe-replete rats.5. Absorption of 59Fe from the isolated haemoproteins from chicken meat was unaffected by soya-bean proteins but 59Fe absorption from the main non-haem-Fe fractions was strongly inhibited, particularly from haemosiderin.

scholarly journals Digestibility of casein, formaldehyde-treated casein and soya-bean protein in relation to their effects on serum cholesterol in rabbits

1989 ◽  
Vol 62 (2) ◽  
pp. 331-342 ◽  
Author(s):  
Marja W. Kuyvenhoven ◽  
Wojciech F. Roszkowski ◽  
Clive E. West ◽  
Ron L. A. P. Hoogenboom ◽  
Ria M. E. Vos ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Serum Cholesterol ◽  
Important Determinant ◽  
Protein Digestibility ◽  
Protein Isolate ◽  
Soya Bean ◽  
Water Soluble ◽  
Casein Diet ◽  
Insoluble Protein ◽  
Bean Protein

Adult male rabbits were fed on semi-purified diets containing soya-bean protein isolate, casein or formaldehyde-treated casein as the protein source and 1 g cholesterol and 5 g of the non-absorbable marker chromic oxide/kg diet. The concentration of cholesterol in serum and in liver was increased on both the casein and formaldehyde-treated-casein diets. Excretion of bile acids and their concentration in faeces were lower in rabbits fed on casein or formaldehyde-treated casein when compared with rabbits fed on soya-bean protein. Apparent digestibility of nitrogen was lowest when formaldehyde-treated casein was fed, and highest on the casein diet. In rabbits fed on casein treated with formaldehyde, higher proportions of N were found in the water-soluble and trichloroacetic acid-insoluble protein fractions of the gastrointestinal tract contents compared with rabbits on the other two diets. Absorption of phosphate from the gastrointestinal tract was higher in rabbits fed on casein than in rabbits fed on soya-bean protein or formaldehyde-treated casein. The results indicate that, in rabbits, protein digestibility may not be an important determinant of serum cholesterol.

scholarly journals The effect of dietary raw and autoclaved soya-bean protein fractions on growth, pancreatic enlargement and pancreatic enzymes in rats

1982 ◽  
Vol 47 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Michael Naim ◽  
Arieh Gertler ◽  
Yehudith Birk
Keyword(s):  
Heat Treatment ◽  
Growth Rate ◽  
Whey Proteins ◽  
Optimal Growth ◽  
Soya Bean ◽  
Pancreatic Enzymes ◽  
Growth Depression ◽  
Pancreatic Proteases ◽  
Soya Bean Meal ◽  
Ti Content

1. Raw soya-bean meal (RS) was fractionated into soya-bean lyophilized extract (SLE), soya-bean lyophilized residue (SLR), acid-precipitated proteins (APP) and whey proteins.2. Trypsin (EC 3.4.21.4) and chymotrypsin (EC 3.4.21.1) inhibitors (TI) were soluble at pH 8 and remained soluble after the extract was acidified to pH 4·4. Except for whey, heating abolished, almost totally, their inhibiting activity.3. Feeding SLE diet (high TI content) and APP diet (low TI content) resulted in growth depression below the RS level. Feeding the SLR diet resulted in an optimal growth. Feeding diets containing heated fractions improved the growth rate though not to the level observed with heated RS (HS) diet.4. RS, SLE, APP and whey diets produced similar pancreatic enlargement which could be totally (RS, whey) or partially (SLE, APP) abolished by heating.5. Feeding the RS diet reduced pancreatic amylase content. The factor responsible for this effect cofractionated with SLE and whey proteins.6. Two groups of factors in the various diets were probably responsible for the elevation in pancreatic proteases. The first group were the heat-labile factors present in RS, SLE and whey whereas the second group resisted the heat treatment and were found in APP and SLR.7. The results suggest that for optimal growth rate of rats, heat treatment should be given to the unfractionated soya-bean proteins rather than to the isolated fractions. The results further indicated that TI are not the only factors that can lead to pancreatic enlargement and changes in pancreatic enzymes composition.

Activation of Inactive Plasma Renin: Evidence that Both Cryoactivation and Acid-Activation Work by Liberating a Neutral Serine Protease from Endogenous Inhibitors

1978 ◽  
Vol 55 (s4) ◽  
pp. 135s-138s ◽  
Author(s):  
Steven A. Atlas ◽  
John H. Laragh ◽  
Jean E. Sealey
Keyword(s):  
Serine Protease ◽  
Plasma Renin ◽  
Lima Bean ◽  
Trypsin Inhibitors ◽  
Soya Bean ◽  
Acid Activation ◽  
Alkaline Ph ◽  
Two Phase ◽  
Ph Optimum

1. We have found that ‘acid’-activation of inactive human plasma renin is a two-phase process. About 30% of activation occurs during dialysis to pH 3·3; the remaining 70% occurs at alkaline pH. 2. The ‘alkaline phase’ of activation has a pH optimum between 7·5 and 8·4. It is inhibited by unacidified plasma and by soya-bean or lima-bean trypsin inhibitors. 3. ‘Cryoactivation’ of inactive plasma renin, which occurs at −4°C and alkaline pH, is also inhibited by soya-bean or lima-bean trypsin inhibitors and by the serine protease inhibitors di-isopropylphosphorofluoridate and benzamidine. 4. Thus endogenous neutral serine proteases participate in the activation of inactive plasma renin in vitro. Their action is prevented in the circulation by inhibitors which are inactivated by acid or cold.

Proteinases released in vitro by the parasitic stages of Teladorsagia circumcincta, an ovine abomasal nematode

Parasitology ◽  
1995 ◽  
Vol 110 (4) ◽  
pp. 465-471 ◽  
Author(s):  
C. J. Young ◽  
J. B. McKeand ◽  
D. P. Knox
Keyword(s):  
Molecular Size ◽  
Dependent Manner ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Protein Substrates ◽  
Teladorsagia Circumcincta ◽  
Fourth Larval Stage ◽  
Sensitivity Studies ◽  
Ph Dependent

SUMMARYProteinases released during in vitro maintenance of third (L3) and fourth larval stage (L4) and adult Teladorsagia circumcincta (formerly Ostertagia circumcincta), an ovine abomasal nematode parasite, were characterized on the basis of pH optima, molecular size and specific proteinase inhibitor sensitivity. Enzyme activity was maximal at alkaline pH and stage-specific release was demonstrated. Proteinases released by the adult parasite degraded a variety of protein substrates including plasminogen, albumin and haemoglobin, in a pH-dependent manner. At alkaline pH fibrinogen degradation was restricted to the α and β peptide chains although the γ peptide chain was also degraded at acidic pH. Inhibitor sensitivity studies indicated that degradation was predominantly due to metalloproteinases although aspartyl proteinase activity was indicated at acidic pH.

scholarly journals Effects of soya-bean protein and casein on serum cholesterol levels in rats

1980 ◽  
Vol 44 (2) ◽  
pp. 113-121 ◽  
Author(s):  
Y. Nagata ◽  
K. Imaizumi ◽  
M. Sugano
Keyword(s):  
Serum Cholesterol ◽  
Dietary Protein ◽  
Protein Isolate ◽  
Soya Bean ◽  
Male Rats ◽  
Cholesterol Levels ◽  
Definite Pattern ◽  
Neutral Sterols ◽  
The Difference ◽  
Bean Protein

1. The effect of the soya-bean protein isolate and casein, both given 200 g/kg diet for 3–4 weeks, on serum cholesterol was compared in male rats.2. Soya-bean protein exerted a hypocholesteraemic effect only in a cholesterol-free low-fat (10 g maize oil/kg) diet, when the lowering action appeared independent of the strain of the rat or the feeding pattern. The results obtained with diets containing cholesterol or higher levels of fats or both showed no definite pattern of response.3. Although the decrease in serum cholesterol appeared greater in α-lipoprotiens than in β-lipoproteins, the proportion of the former to total cholesterol remained almost unchanged. The concentration of serum apo A-I was significantly lower in rats given the vegetable protein.4. Rats given soya-bean protein excreted significantly more neutral sterols.5. The serum amino acid pattern did not reflect the difference in dietary protein. Addition of cholesterol to the diets modified the serum aminogarm, the decrease in threonine being most marked in both protein groups.6. This study shows that the hypocholesteraemic action of soya-bean protein is easily modified by the type of diet.

scholarly journals A longitudinal cross-over study of serum cholesterol and lipoproteins in rabbits fed on semi-purified diets containing either casein or soya-bean protein

1982 ◽  
Vol 47 (2) ◽  
pp. 213-221 ◽  
Author(s):  
Anthony H. M. Terpstra ◽  
Christopher J. H. Woodward ◽  
Clive E. West ◽  
Henk G. Van Boven
Keyword(s):  
Serum Cholesterol ◽  
Low Density Lipoproteins ◽  
Soya Bean ◽  
Cholesterol Concentration ◽  
Low Density ◽  
Very Low Density Lipoproteins ◽  
Serum Cholesterol Concentration ◽  
Cholesterol Levels ◽  
The Cross ◽  
Bean Protein

1. Two groups, each of six rabbits, were fed on semi-purified diets containing either 400 g casein or 400 g soya-bean protein/kg for 20 d and then the diets of the two groups were crossed-over.2. Just before the cross-over, the serum cholesterol concentration (mean ± SE) was 3068 ± 592 and 800 ± 143 mg/l for the groups fed on casein and soya-bean protein respectively.3. Changes in the serum cholesterol concentration were observed 1 d after crossing-over the diets. By 10 d, the cholesterol levels in the two groups had also crossed-over.4. The changes in serum cholesterol level after the cross-over were reflected in the very-low-density lipoproteins (VLDL) and low-density lipoproteins (LDL).5. Lipoprotein protein concentrations in the LDL changed in the same way as cholesterol. In the VLDL however, the protein concentration decreased in both groups after the change in diet.6. The cholesterol:protein values for the LDL and VLDL markedly increased in the rabbits changed from the soya-bean-protein diet to the casein diet, reaching a maximum 2 d after the cross-over. In the animals switched from casein to soya-bean protein, the values progressively declined.7. The source of dietary protein exerts a rapid effect on the composition of both the VLDL and LDL which is proposed to be attributed to changes in the number and size of lipoprotein particles.

scholarly journals Use of guanidinated dietary protein to measure losses of endogenous amino acids in poultry

1994 ◽  
Vol 71 (4) ◽  
pp. 515-529 ◽  
Author(s):  
P. Siriwan ◽  
W. L. Bryden ◽  
E. F. Annison
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Broiler Chickens ◽  
Soya Bean ◽  
Meat Meal ◽  
Lysine Residues ◽  
Soya Bean Meal ◽  
Bean Protein ◽  
Endogenous Amino Acid

Guanidinated proteins when fed to non-ruminants provide values for both endogenous amino acid losses and amino acid digestibilities, provided that the homoarginine residues in the treated protein are randomly distributed. Earlier studies have established that guanidination has only minor effects on the structure of the protein and, in particular, on its susceptibility to proteolysis. Furthermore, we have confirmed that homoarginine behaves as a typical amino acid in the small intestine. Lysine residues in casein and soya-bean protein, and in the proteins of cotton-seed meal, meat meal, soya-bean meal, maize, sorghum and wheat were converted to homoarginine by guanidination, the extent of conversion ranging from 37–68%. Sequential proteolysis in vitro of these guanidinated materials showed that the ratios of homoarginine to other amino acids remained unchanged for casein and soya-bean protein, indicating random distribution of homoarginine residues, but not for all the amino acids in meals and cereals. The use of guanidinated casein as the sole protein source in diets fed to broiler chickens allowed measurement of endogenous losses of amino acids under normal feeding conditions and calculation of true digestibilities of dietary amino acids at the ileum. Endogenous amino acid losses measured by the use of guanidinated casein (15.3 g/kg dry matter (DM) intake) were significantly higher (P < 0.001) than values obtained by feeding a N-free diet (5.4 g/kg DM intake), or by regression analysis to zero N intake (72 g/kg DM intake)

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