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R Toullec

Publications and source records attributed to R Toullec.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Effect of hypoxia on plasma concentrations of gastrin and gastric inhibitory polypeptide (GIP) in newborn calves].

Calves were subjected to experimental hypoxia from 0.5 to 4 h after birth. The plasma level of immunoreactive gastric inhibitory polypeptide was higher (P less than 0.05) than in control calves during hypoxia and 2 and 7 h later. However, the gastrin level was not lower during treatment and was higher (P less than 0.05) 3, 6, and 13 h later. Hypoxia could have changed circulating levels or degradation rates of these peptides and could have delayed abomasal emptying.

Animals↗
PubMed1990

[Modulation of pancreatic chymotrypsin messenger RNA during post-natal development and weaning in calves].

Levels of chymotrypsin mRNA in the pancreatic tissue of preruminant calves were significantly decreased on d 28 and to a lesser extent on d 119 as compared to those of newborns. Enzymic activity regularly increased during the same period. By contrast, both chymotrypsin-specific activity and the mRNA level in the ruminant animals were enhanced on d 119 (1.4- and 2.3-fold, respectively), suggesting that some pretranslational regulation of the chymotrypsin gene was induced by weaning.

Animals↗
PubMed1989

[Digestion of pea and soya proteins in the preruminant calf. II. Apparent digestibility at the end of the ileum and the digestive tube].

Three milk substitutes (control, pea and soya-bean) were given to 6 preruminant calves fitted with re-entrant canulas in the terminal ileum. In the control diet, protein was almost entirely provided by skim milk powder. In the pea diet, a pregelatinized dehulled pea flour provided 33.5% of the protein, the remainder being supplied by skim milk powder. In the soya-bean powder diet 73.2% of the protein were provided by a soya-bean isolate and the remainder by whey powder. The apparent digestibility of total nitrogen was significantly lower with the pea and soya-bean diets. than with the control diet (0.92, 0.91 and 0.95 at the end of the ileum, 0.92, 0.94 and 0.97 at the end of the whole digestive tract, respectively). Also the ileal digestibility of most amino acids decreased with the pea and soya-bean diets; the differences were greatest for cystine (-0.6; non significant) with the pea diet and for threonine (-0.7; P less than 0.01) with the soya-bean diet. Irrespective of the diet the protein escaping digestion in the small intestine appeared to be mainly from endogenous and bacterial origin. Although small amounts of partially degraded dietary protein could be present in ileal digesta with the pea and soya-bean diets, their true digestibility was probably very high.

Amino Acids↗
PubMed1989

[Digestion of pea and soya proteins in the preruminant calf. I. Circulating levels of nutrients, antibody formation and intestinal permeability to macromolecules].

Three milk-substitutes (control, pea and soya-bean)were given to 6 preruminant calves. In the control diet protein was almost entirely provided by skim milk powder. In the pea diet a pregelatinized dehulled pea flour provided 33.5% of the protein, the remainder being supplied by skim milk powder. In the soya-bean diet, 73.2% of the protein were provided by a soya-bean isolate and the remainder by whey powder. The concentrations of plasma triglycerides and the free alpha-amino nitrogen in the peripheral blood were lower with the pea and soya-bean diets than with the control diet before the morning meal, but became higher after feeding. That suggested a faster abomasal emptying of fat and protein with the pea and especially the soya-bean diet. Systemic antibody responses were induced against pea protein but not against soya-bean protein. No effect of the diet on the plasma concentration of immunoreactive beta-lactoglobulin was apparent after 6 days, suggesting there was no important change in gut permeability at least at that time.

Animals↗
PubMed1988

[Gastro-entero-pancreatic production and hepatic uptake of gastrin and somatostatin in the preruminant calf receiving milk proteins or milk serum].

In preruminant calves total splanchnic production of immunoreactive somatostatin and gastrin did not change when casein was replaced by whey protein in the diet, but gastrin secretion was more rapid for the first 3 postprandial hours. Loss during passage through the liver was equivalent to splanchnic production for somatostatin, but was very low for gastrin.

Animals↗
PubMed1988

[Antibodies against dietary proteins and intestinal permeability to macromolecules in the preruminant calf receiving pea flour].

Feeding a milk-substitute diet containing raw pea flour to preruminant calves resulted in the production of anti-pea protein antibodies. Immunoreactive legumin could be evidenced in blood plasma between the second and the fifth meal. Plasma immunoreactive beta-lactoglobulin increased up to the third or seventh week and decreased thereafter, showing a transient rise of gut permeability to macromolecules, probably due to intestinal inflammatory reactions.

Animals↗
PubMed1988

[Mechanisms implicated in the intestinal allergic reaction to soya proteins in the preruminant calf].

Studies of intestinal motility in calves given antigenic soya protein or sucrose showed disturbances linked to diarrhoea. Disorders arising from feeding antigenic soya protein were distinct from abnormal motility induced by indigestible carbohydrate. Suppression of the digestive disorders by a drug having anti-allergic properties implied the involvement of an immunological mechanism.

Animals↗
PubMed1986

Effect of soya protein on digestive enzymes, gut hormone and anti-soya antibody plasma levels in the preruminant calf.

The effect of a milk substitute diet containing concentrated soya protein on secretory functions of the abomasum and pancreas and on plasma concentrations of gut hormones and soya antibodies was studied. Sixteen calves aged 12-19 weeks were given a milk substitute in which a major part of the protein source was either soya concentrate (soya diet) or skim milk (control diet). The soya diet was prepared by hot aqueous ethanol extraction of soya bean meal to remove oligosaccharides and inactivate antigenic constituents. Circulatory IgG antibodies against soya proteins were found in all of the calves when they were 16 weeks of age. Their titres increased slightly between 16 and 19 weeks, irrespective of the diet. It seems unlikely that the presence of these antibodies was related specifically to the feeding of the soya concentrate. At slaughter the weight of the gastric mucosa and pancreas and quantities of pancreatic protein together with specific activities of trypsin and chymotrypsin were significantly lower (17, 20, 16, 30 and 36%, respectively) with the soya diet. The quantities of enzymes in the gastric mucosa or the specific activity of pancreatic amylase were not affected, whereas that of lipase increased by 26%. Total enzyme activities as well as units per kg live weight gave significant differences only for trypsin and chymotrypsin which were reduced by 43 and 38%, respectively. With the soya diet, fasting concentrations of gastric inhibitory peptide (GIP) and secretin in plasma samples were significantly lower (49 and 34%, respectively). Values of GIP were also lower (54%) 1 h after feeding. In contrast, postprandial values of cholecystokinin (CCK) were 1.4 times greater. No significant differences were found between the two diets for gastrin, vasoactive intestinal peptide (VIP), bovine pancreatic polypeptide (BPP), somatostatine and motilin. In general these observations could be explained, in part, by the more rapid passage of protein and fat from the abomasum to the duodenum following feeds containing soya concentrate. However, these differences in concentrations of gut hormones did not seem to be related to variations in the weights of gastric mucosa and pancreas or activities of pancreatic enzymes.

Abomasum↗
PubMed1986

Digestion of milk, fish and soya-bean protein in the preruminant calf: flow of digesta, apparent digestibility at the end of the ileum and amino acid composition of ileal digesta.

1. Digesta were collected from eleven preruminant calves fitted with re-entrant (four calves in Expt 1 and three in Expt 2) or single cannulas (four calves in Expt 1) in the terminal ileum. Collection periods lasted 24 h (Expt 1) or 96 h (Expt 2). 2. Two milk-substitutes (fish and soya bean) and a control diet were given to the calves. In the control diet, protein was entirely provided by skim-milk powder. In the other two diets, protein was provided mainly by a partially hydrolysed white-fish protein concentrate or a soya-bean protein concentrate prepared by extracting soya-bean meal with hot aqueous ethanol. 3. In Expt 1, flow rates of fresh matter, dry matter, nitrogen and ash exhibited two maxima between 6 and 8 h after the morning meal and between 4 and 6 h (control and soya-bean diets) or 6 and 8 h (fish diet) after the evening meal. Minimum pH values were observed at times of maximum flow rate. Variations observed in the flow rates and pH values were larger with fish and especially soya-bean diets than with the control diet. 4. The apparent digestibility of the three diets in the terminal ileum was significantly higher in Expt 2 than in Expt 1: for N, the values were 0.92, 0.83 and 0.75 (Expt 1), and 0.94, 0.87 and 0.88 (Expt 2) with the control, fish and soya-bean diets respectively. 5. The amount of N apparently absorbed in the terminal ileum represented 90-96% of the amount that disappeared from the whole digestive tract in Expt 1 and 95-99% in Expt 2. 6. In Expt 1 the amino acid (AA) composition of digesta changed little with the flow rate when the calves were given the control diet (from 158 to 179 g glutamic acid/kg AA). With the fish and soya-bean diets the AA composition was similar to that observed with the control diet when the flow rate was minimum, but differences became apparent as the flow rate increased (281 and 161 g glutamic acid/kg AA for the soya-bean and control diets respectively with maximum flow rate). In Expt 2, the mean compositions of the digesta were very similar to the means obtained in Expt 1. 7. Different comparisons with dietary, endogenous and bacterial proteins indicated that for the three diets a common mixture containing approximately 65% endogenous and 35% bacterial proteins reached the terminal ileum.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1986

[Digestion of milk proteins in the abomasum of the preruminant calf].

Gastric digestion of milk proteins has been studied in the preruminant calf by analysing gastric effluents in the duodenum after the ingestion of 5 different diets: whole milk, skim milk, casein solution in water, casein solution with minerals, whey. The amino acid composition of the gastric effluents and HPLC analysis of the latter show that the major part of the whey proteins were evacuated rapidly without any proteolysis and after milk ingestion. On the contrary, all the caseins were largely proteolysed and arrived slowly in the gut. The major part of the peptides obtained came from alpha s1 casein. Only a few peptides, principally CMP, were quickly emptied from the stomach.

Abomasum↗
PubMed1985

Enzyme potentialities of the abomasum and pancreas of the calf. II. Effects of weaning and feeding a liquid supplement to ruminant animals.

Thirty-nine male Friesian calves, divided into three groups (L, S and SL), were reared until they were 147 to 175 days old. Group L calves remained preruminant until slaughter. Group S calves were weaned between 5 and 9 weeks of age and then received a concentrate feed and dehydrated fescue ad libitum. Besides this diet, group SL calves received a liquid supplement containing whey powder and soyabean oil meal, supplying a total of 940 g of dry matter and 5,060 g of water per day. The slaughter age of the calves in each group was chosen so that carcass weight in the three groups was similar. At slaughter, the abomasum and pancreas of each animal were collected and the gastric (chymosin and pepsin) and pancreatic (chymotrypsin, trypsin, lipase and amylase) enzymes were assayed. Weaning caused a decrease in the chymosin content and an increase in the pepsin content of the abomasum. The amount of chymosin per kg of carcass was on the average 2.8-fold lower and that of pepsin 1.9-fold higher in groups S and SL than in group L. The amount of pepsin tended to be higher in group S than in group SL, but only the difference observed (36%) for the total amount was significant. In group S, the pancreata showed more chymotrypsin, trypsin and amylase activities but less lipase activity than in group L; the observed differences in these activities per kg of carcass were 32, 49, 70 and 24%, respectively. The activities of group SL were lower than those of group L for trypsin, chymotrypsin and lipase but higher for amylase (17, 12, 44 and 18%, respectively). Group SL exhibited lower activities than group S (55, 67, 16 and 44%, respectively, for trypsin, chymotrypsin, lipase and amylase). Weaning appeared to induce large changes in abomasal and pancreatic enzyme potentialities which exhibited patterns similar to the variations in the amounts of substrate intake. In our experimental conditions, giving a liquid supplement to ruminant calves had a depressive effect on the activities of the enzymes (except chymosin), in the pancreas and the abomasum.

Abomasum↗
PubMed1985

In vivo milk digestion in the calf abomasum. III. Amino acid compositions of the digesta leaving the abomasum.

Calves were fed five different test meals: whole milk, skim milk, 3% whole casein solution, 3% whole casein in simulated milk ultrafiltrate, and whey. The digesta leaving the abomasum before feeding and during the first 7 postprandial hours were collected by fractions. After precipitation with 12% TCA, the amino acid compositions of the sediments and the supernatants were determined and compared by multivariate analysis. The composition of prefeeding digesta was similar to that of gastric juice. When the calves were fed the two casein diets, the amino acid composition of the sediments changed little with time. In contrast, the changes observed in the composition of the supernatants suggested rapid abomasal emptying of caseino-macro peptide. With the whey diet, it was not possible to evidence more rapid hydrolysis or abomasal emptying of any particular whey protein. During the first 10 min following the ingestion of whole or skim milk, the amino acid composition of the sediment was close to that of milk protein. Immediately afterwards, the composition of the sediment was similar to that of whey protein. Thereafter, the composition of the sediment became more like that of casein and almost reached that of casein during the 7th hour. The amino acid composition of the supernatant was similar to that obtained with the casein diets; this fact suggests that the small peptides produced by proteolysis in the abomasum originated more from casein than from whey proteins.

Abomasum↗
PubMed1984

Enzyme potentialities of the abomasum and pancreas of the calf. I.--Effect of age in the preruminant.

The effect of age on the enzyme potentialities of abomasum (chymosin and pepsin) and pancreas (chymotrypsin, trypsin, colipase and amylase) was studied in the preruminant calf. Three foetuses were collected after slaughter of their dams (260 d of gestation) and 32 calves were maintained as preruminant and slaughtered between birth and 147 d of age. The abomasal mucosa and pancreata were collected and analysed. The abomasal and pancreatic glands of the foetus contained large amounts of enzymes, except pepsin and amylase. On a liveweight basis, the amount of chymosin was maximal at 1.5 d post partum and decreased thereafter; the amount of pepsin increased until 21 d and then did not change. The development of pancreatic enzyme activities was usually the reverse of that of chymosin; amylase activity was particularly low at birth. After birth, the development of secretory potentialities could be divided into three phases: during the colostral period, the trend of pancreatic activities was the reverse of that observed for abomasal activities; from 1.5 to 21 d, most of the enzyme potentialities (except those of chymosin and amylase) appeared to be stimulated by intake level; after 21 d (1.5 d for chymosin and amylase), the development of secretory potentialities appeared to depend more on age than on intake.

Abomasum↗
PubMed1984

In vivo milk digestion in the calf abomasum. I. Whole-casein digestion.

Peptide products insoluble in 12% TCA and obtained in the proximal duodenum of calves at different times after ingestion of casein solutions were characterized by polyacrylamide gel electrophoresis, electrofocusing and SDS pore gradient gel electrophoresis. With a 3% whole-casein solution in water the disappearance of electrophoretic bands corresponding to alpha s1 and beta caseins was observed after about 1 h 30. After 3 h and up to 7 h very acidic peptides appeared. With a 3% whole-casein solution in simulated milk ultrafiltrate, comparable patterns were obtained. Nevertheless, the acidic peptides appeared sooner, i.e. they were already detected in the first sample collected after meal ingestion. With the 2 diets, the importance of gastric proteolysis was demonstrated by the appearance of a great number of peptides of various sizes, charges and pHi. On the other hand, an effect of salts on casein proteolysis was detected.

Abomasum↗
PubMed1983

Effects of age and weaning on enzyme activities of abomasum and pancreas of the lamb.

The effect of age and weaning on enzyme activities of abomasum and pancreas of the lamb was studied. Sixty-nine lambs were either maintained at the preruminant stage until 42 days of age or weaned between 20 and 30 days. They were slaughtered between birth and 100 days, and the mucosa of their abomasum and their pancreas were collected. At 2 days of age there was a threshold of glandular growth and of development of enzyme secretory potentialities. Pancreas showed an extensive hyperplasia without growth until day 2; its weight increased after day 7 but only by hypertrophy. Quantities of gastric enzymes in relation to empty live weight increased between birth and 2 days, but that of chymosin then decreased, whereas pepsin did not change significantly; effects of weaning were similar. The evolution of pancreatic enzyme activity was usually the reverse of that of chymosin; however, trypsin activity was low at birth and that of colipase did not increase at weaning. The ratio of colipase to lipase was always higher than 1, showing that lipase always was saturated in the lamb. The pancreas seemed to take over the secretion of abomasal proteolytic enzymes. Potentialities of enzyme digestion appeared to be influenced mainly by the age or weight of the animal; these potentialities were minimal for at least several days during the first neonatal week and, if there was enzymatic adaptation to the amounts of the ingested substrate, it did not occur rapidly.

Abomasum↗
PubMed1983

[Digestion of milk proteins in the abomasum of the preruminant calf. Gastric evacuation after a test meal].

In this study, we used fasted, preruminant calves fitted with a double proximal cannula in the duodenum; gastric evacuation was investigated by recovering products leaving the abomasum after a test meal. Five types of meal were given: whole milk, skimmed milk, casein solution in water, casein solution in a mineral medium simulating the permeate of highly-filtered milk, and whey. Gastric emptying of nitrogen was relatively slow. The coagulation of "milk diets" slowed down this emptying. Precipitation of "casein diets" at acid pH also slowed down emptying, but to a lesser degree. The "casein diets", more proteolyzed than the "milk diets", released larger amounts of non-protein nitrogen (NPN) into the intestine. Calcium emptying was highly related to NPN emptying, demonstrating the important role of acid peptides (phosphopeptides) from casein hydrolysis.

Abomasum↗
PubMed1982

[Effect of the kinetics of gastric emptying of food on blood insulin levels in the preruminant calf].

The aim of this work was to clarify the possible role of blood metabolites (glucose, aminoacids, triglycerides) in the regulation of postprandial blood insulin in the preruminant calf. The animals used were 6 male Friesian bull calves with an average weight of 80 kg. They were divided into groups I and II. During the first experimental period (A), group I received a control diet that contained skim-milk powder as the only protein source, whereas group II received an experimental diet containing fish protein concentrate as the main protein source. During the second experimental period (B), the diets were switched. It was previously shown that the rate of fat and amino acid absorption increased when milk proteins in such milk substitutes were replaced by hydrolyzed fish proteins (Guilloteau et al., 1975). The results showed that during any experimental period in the control group, there was a decrease in the postprandial blood free amino nitrogen. Blood triglycerides exhibited a small increase at 0.5 h after the meal but a large decrease at 1-4.5 h. The meal also resulted in a very large increase in blood glucose with maximal values occurring at 1-4.5 h. Blood insulin showed a large increment at 0.5 h then increased slowly, peaking at 2-3 h. The postprandial increase in blood insulin was less during the first experimental period than during the second one. In calves fed the fish diet, blood free amino nitrogen and blood triglycerides showed a large postprandial increase. Blood glucose exhibited a smaller postprandial increment than in the controls and began to decrease at half an hour. In contrast, the trend of changes in blood insulin was the same as in the controls (i.e. a maximum at 3 h occurring after a large increase at 0.5 h). There were no significant differences in blood insulin between the two experimental periods. It was lower in the calves fed the fish diet than in the controls during the first experimental period; during the second period, it was similar in both groups. From these observations, it may be inferred that, as compared to the control diet, the fish diet resulted in a decrease in glucose stimulation of postprandial insulin secretion; in contrast, the effect of aminoacids and lipids may be increased.

Amino Acids↗