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1.
A metabolism trial was conducted with 18 crossbred (Finn x Dorset x Suffolk) wethers, fitted with indwelling jugular catheters and abomasal and ileal cannulas, to determine the effects of high levels of i.v.-infused K and Na on mineral metabolism. The wethers (40 kg) were fed 800 g daily of a 60% concentrate diet in two equal portions at 0800 and 1900. Six wethers were infused randomly with 19 g K+, six with 10.6 g Na+ (chloride salts) and the other six with physiological saline solution (1.2 g Na) per day. Potassium chloride or NaCl infusion had no effects on apparent absorption, retention, flow or partial absorption of Mg, Ca and P in the digestive tract compared with physiological saline infusion. With all treatments, Mg and Ca were absorbed proximal to the abomasal cannula. Magnesium was secreted into, whereas Ca and P were absorbed from, the small intestine. Phosphorus was secreted both in the stomach and large intestinal regions of the digestive tract. Major sites of K and Na absorption were the small and large intestines, respectively. Infusion of K increased (P less than .05) retention of K compared with Na infusion. Infusion of Na increased (P less than .05) excretion and retention of Na compared with K infusion. Serum minerals were not changed by K or Na infusion compared with saline. The results of this experiment indicate that the depressing effects of K on Mg absorption are not attributable to high levels of absorbed K, but rather to K present in the digestive tract prior to the small intestine.  相似文献   

2.
Isosmolar oral rehydrating solutions (ORS) used to treat diarrheic calves are low in energy. In contrast, hyperosmolar ORS may have a dehydrating effect. This study was designed to compare the net water and glucose absorption from the small intestine of normal calves given isosmolar or hyperosmolar ORS. Six calves were used for the experiment. A reentrant ileal cannula was implanted surgically. Each calf was fed with either the isosmolar or the hyperosmolar solution. The next day, the second solution was given. Both contained chromium EDTA as a nonabsorbable marker. Changes in the hematocrit, total plasma protein, plasma osmolality, plasma glucose concentration, and ileal volume, osmolality, glucose content, and chromium concentration were monitored for 10 hours. The only statistically significant difference was in the post-feeding plasma glucose level: it peaked at the higher level (p less than 0.05) in calves fed the hyperosmolar solution. In normal calves, the hyperosmolar ORS had no effect on the hydration or on the small intestinal fluid composition.  相似文献   

3.
12 pigs were divided into 4 groups. All animals received an identical basal diet deficient in lysine and additional isonitrogenous amounts of 66.4 mmol N in the form of 15N-lysine and 15N-urea resp. orally or caecally. Caecal application was carried out as permanent infusion through caecal cannulae. N- and 15N-balances were ascertained of all animals and the remain of the labelled nitrogen was determined. From the comparison of the N-balances the conclusion can be drawn that though caecally applied N-compounds, whether they were infused as amino acids or as non-amino acid-N, disappear in the large intestine, i.e. are digested, do not, however, improve the N-balance but are excreted as additional urine-N. Subsequent to oral application, lysine or urea are almost quantitatively absorbed in the small intestine. Absorbed lysine is used in the synthesis of body protein, absorbed urea, however, is almost completely excreted in urine (83% of the 15N-amount absorbed). 15N-excretion in faeces after the oral application of 15N-lysine and 15N-urea resp. was less than 1% of the 15N-amount applied, after caecal infusion, however, it was approximately 6%, the biggest part of which (70-77%) was incorporated in bacteria protein. After caecal infusion the main quota of the infused 15N-amount (greater than or equal to 80%) was excreted in urine, most of it in the form of urea. After the oral application of 15N-lysine this could be detected in both the TCA-soluble fraction of the serum and the serum protein. After caecal infusion 15N in the TCA-soluble fraction of the serum could mainly be found as NPN, absorption and incorporation of intact 15N-lysine were considerably lower. An calculation showed that the maximum of the absorbed 15N-amount in the form of lysine was 3% and that of the infused amount was 1.8%. It can generally be doubted that the absorption of lysine in the large intestine is significant in the protein metabolism. The absorption of utilizable lysine is practically completed at the end of the ileum. In the large intestine mainly the ammonia by the catabolic activity of the intestinal flora is absorbed and subsequently excreted through the intestines.  相似文献   

4.
Two metabolism trials were conducted with 12 crossbred wether lambs, each surgically equipped with a ruminal catheter and abomasal and ileal cannulae, to study the effect of K infusion in different sites of the digestive tract on site of absorption and flow of minerals. The treatments consisted of the infusion of 33.6, 12.0 or 12.0 g K/d as bicarbonate into either the rumen, abomasum or ileum, respectively. Each trial consisted of a minimum 5-d preliminary period, five 3-d collection periods to determine mineral balance and a 6-d sampling period to determine mineral flow and site of absorption. Chromic oxide was incorporated into the diet for use as a marker. Magnesium was absorbed primarily from the preintestinal region. Ruminal infusion of K tended to decrease preintestinal Mg absorption. Absorption of Mg in the entire tract was decreased (P less than .05) 43% when K was infused into the rumen. There was a slight absorption of Mg in the small intestine, followed by a net secretion into the large intestine. Serum Mg levels tended to be depressed in lambs infused with K intraruminally. Calcium flow from the preintestinal region was decreased (P less than .05) by infusion of K into the rumen. Only lambs infused with K in the rumen had a net secretion of Na into the small intestine. The large intestine was the primary site of net Na absorption for ruminal-infused lambs. Phosphorus flow from the preintestinal region was decreased (P less than .05) by infusion of K into the rumen. Potassium flow from both the preintestine and small intestine was increased (P less than .05) by ruminal K infusion. The infusion of K into the rumen, abomasum or ileum increased (P less than .05) the total absorption of K, with the small intestine being the major absorptive site. The infusion of potassium bicarbonate into the rumen of sheep raised (P less than .05) the pH of the ruminal contents 15%. Ruminal infusion of K depresses Mg absorption, while the infusion of K into the abomasum or ileum does not affect Mg absorption. Therefore, the role of K in grass tetany may be via this depression of Mg absorption.  相似文献   

5.
Four 40 kg castrated male pigs fitted with simple 'T' cannulas in the terminal ileum were given diets of varying crude fibre content in a change-over experiment with two periods. The basal diet was composed of wheat and fishmeal supplemented with minerals and vitamins. To this was added varying levels of partially hydrolysed straw meal to give crude fibre contents ranging from 40 to 132 g/kg. After adaptation to the particular levels of straw meal, faeces and ileal digesta were collected during successive 24 h periods. Nutrient digestibility values were determined by the chromic oxide ratio method. The addition of treated straw meal to the diet had little or no influence on the DM content of digesta or faeces. The excretion of N in faeces increased with increasing fibre intake but there was no effect on urine N excretion. The overall apparent digestibility of N was reduced from 89 to 79% as crude fibre intake increased from 40 to 132 g/kg but ileal apparent digestibility of N remained constant at about 68%, suggesting that the effect was mediated through hindgut bacteria. Increased fibre intake caused increased net secretion of Na in the small intestine and reduced the apparent absorption of P in the large intestine.  相似文献   

6.
The aim of the study was to measure the effect of creep feeding during lactation on net absorption in the small intestine at 4 days after weaning. Intermittent suckling was used to increase creep feed intake during lactation. Creep feed containing chromic oxide was provided. Based on the colour of the faeces, piglets were classified as ‘eaters’ or ‘non-eaters’, respectively. At day 4 after weaning, an in vivo small intestine segment perfusion test was performed at 5 sites along the small intestine in 24 piglets (12 eaters and 12 non-eaters). At both sides of each intestinal segment a tube was fitted to perfuse and drain fluid in order to assess net absorption. Net absorption was higher in eaters than in non-eaters (P < 0.001). Net absorption varied greatly between and within piglets and was highest in the caudal segments of the small intestine (P < 0.001). These data suggest that creep feeding could be a useful tool in the prevention of post-weaning diarrhoea.  相似文献   

7.
Three metabolism trials were conducted with six lambs fitted with abomasal and ileal cannulae to determine the site of supplemental Mg absorption when supplied as dolomitic limestone or magnesium oxide. Magnesium intake was 1.09 g/d for the lambs fed the control diet and 2.21 and 2.10 g for those fed the dolomitic limestone and magnesium oxide supplemented diets, respectively. Irrespective of its source, the major site of Mg absorption was the preintestinal region. Magnesium was secreted in the small intestine in lambs fed all three diets. Magnesium supplementation resulted in an increase (P less than .05) in preintestinal Mg absorption, with magnesium oxide having the highest value. Supplementation had no effect (P greater than .05) on secretion or absorption of Mg from the small and large intestines or total retention of Mg. With all three diets, the major site of Ca absorption was the stomach region with additional absorption taking place in the large intestine. Calcium was secreted in the small intestine of lambs fed all treatments. Generally, K, Na and P were secreted in the preintestinal region and absorbed from the small and large intestines. The major site of K and P absorption appeared to be the small intestine and for Na, the large intestine. Serum minerals were unchanged (P greater than .05) due to treatment, but the levels of Mg, K and inorganic P tended to be higher in lambs supplemented with either of the Mg sources. It appears that the greater utilization of Mg from magnesium oxide vs dolomitic limestone is due to greater absorption of Mg from the forestomach region.  相似文献   

8.
The effects of several thiol compounds on the cytotoxicity induced by chromate (potassium dichromate) were examined. HeLa cells were incubated in Eagle's minimum essential medium (MEM) with or without the chromate alone, or with both chromate and any one of L-cysteine ethyl ester (LCysEE), L-cysteine methyl ester (LCysME), N-acetyl-L-(+)-cysteine, 2,3-dimercaptosuccinic acid (DMSA), 2, 3-dimercapto-1-propanesulfonic acid (DMPS), or dithiothreitol. After a given period of incubation, the number of viable cells was counted using the trypan blue exclusion test and the chromium content of the cells was estimated by atomic absorption spectrophotometry. The results obtained were as follows. 1) Chromate-induced cytotoxicity evaluated by inhibition of cell growth at 3 days of incubation was diminished by all of the thiol compounds tested when the cells were incubated in MEM with 2.5 to 10.0 microM chromate and 25 to 100 microM thiol compounds. 2) All of the thiol compounds produced a concentration-dependent reduction of chromate when a solution of the thiol compound (12.5 to 100 microM) was mixed with a solution of chromate (10 microM) in distilled water. 3) When cells were incubated in MEM with both 10 microM chromate and 25 to 100 microM thiol compounds, the chromium content of the cells at 6 hr of incubation was decreased in a concentration-dependent manner. 4) When these thiol compounds were added to MEM 1 hr before or after chromate, no or little protective effects of these thiol compounds against chromate-induced cytotoxicity and chromium uptake by the cells were observed.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

9.
Eight Holstein steers (four at 300 kg, four at 406 kg) fitted with an elevated carotid artery, hepatic portal and mesenteric venous catheters, and abomasal and ileal cannulas were used in several 4 x 4 Latin square experiments to evaluate small intestinal starch digestion. They were fed alfalfa hay at 1.5% of BW and abomasally infused with water or glucose, corn starch or corn dextrin (one carbohydrate per Latin square) at 20, 40 or 60 g/h, with subsequent determination of small intestinal disappearance and net portal glucose absorption. Increasing the amount of all three carbohydrates infused abomasally increased the amount of carbohydrate disappearing in the small intestine. Increased infusion of glucose caused a continual increase (linear, P less than .01) in net glucose absorption, whereas net glucose absorption for starch and dextrin was maximal at the 20 g/h infusion (quadratic, P less than .05). With the 60 g/h infusion, 94% of the glucose but only 38% of starch and 29% of small intestinal dextrin disappearance could be accounted for as net glucose absorption, leaving a large portion of starch and dextrin disappearance unaccounted for. Of the infused starch and dextrin passing the ileum, 5.8 and 7.3%, respectively, was unpolymerized glucose, indicating that, at least in the distal small intestine, complete starch hydrolysis exceeded the capacity for glucose disappearance. It is concluded that only about 35% of the raw corn starch disappearing in the steer's small intestine resulted in net portal glucose absorption.  相似文献   

10.
铬对热应激下蛋鸡空肠组织结构的影响   总被引：2，自引：1，他引：1  
将处于热应激条件下的 1 92只 35周龄新罗曼褐壳蛋鸡随机分为 6组 ,分别用玉米 豆粕型基础饲粮和添加 1 0 ,2 0 ,30 ,40 ,50g/t含铬量为7 41 0mg/kg的葡萄糖耐量因子 (GTF)的试验饲粮饲喂 52d。试验结束时取试验鸡 36只 ,每组 6只 ,取空肠制作切片观察组织结构。结果试验组空肠绒毛和肠腺的长度与对照组相比均增长 ,肠壁中有大量弥散淋巴组织和淋巴集结。其中添加 50g/t组的肠绒毛与对照组相比差异极显著 ,添加 2 0g/t组的肠腺与对照组相比差异极显著。表明补铬使热应激下蛋鸡空肠绒毛、肠腺的长度增加 ,淋巴组织发达。可以改善消化管的组织结构 ,增强机体的消化和免疫功能 ,具有缓解高温热应激反应的作用  相似文献   

11.
Intestinal uptake of intact maternal lymphocytes by neonatal rats and lambs   总被引：3，自引：0，他引：3  
Two experiments were conducted using neonatal rats and lambs. The intestinal lumen of neonatal rats was infused with radiolabelled syngeneic lymphocytes, whereas the intestine of lambs was infused with radiolabelled allogeneic maternal lymphocytes. The results of both experiments indicated that radiolabelled cells were absorbed by the intestine as judged by autoradiographic studies of intestinal tissue. Furthermore, in lambs it was possible to show that these cells were transported via the lacteal lymph ducts to the mesenteric lymph nodes. These findings suggest another mechanism by which the lactating ewe may confer immunity to its suckled young.  相似文献   

12.
The current experiment was carried out to evaluate the effect of different dietary chromium supplementation sources, chromium oxide (Cr2O3), chromium methionine (Cr‐Met), or chromium yeast (Cr‐yeast), at different levels each (500 or 1,000 ppb) on growth performance, physiological traits, and carcass characteristics of broiler chicks. A total of 490 seven‐day‐old Arbor Acres chicks were randomly distributed into 7 experimental groups each in 10 replicates of 7 birds each. The groups were control, 500 ppb Cr2O3, 1,000 ppb Cr2O3, 500 ppb Cr‐Met, 1,000 ppb Cr‐Met, 500 ppb Cr‐yeast, and 1,000 ppb Cr‐yeast. The results showed significant superiority of the organic chromium sources (Cr‐Met or Cr‐yeast) concerning body weight and weight gain, the group supplemented with 1,000 ppb Cr‐yeast consumed the lowest feed (3,185 g) and had the best feed conversion ratio (1.60) compared to the control (1.73). The chromium treatments recorded significantly better protein and lipid profile, antioxidant status, and immunological parameters than the control group. Similarly, dietary chromium supplementation increased carcass yield and decreased intestinal pathogenic bacteria. In conclusion, supplementing broiler diets with organic chromium sources at 1,000 ppb promotes growth performance, physiological traits, and carcass characteristics; such chromium treatments enhanced the antioxidant status and immunity levels of broilers.  相似文献   

13.
Breath hydrogen concentration and small intestinal malabsorption in calves   总被引：1，自引：0，他引：1  
Breath hydrogen concentrations were measured to assess intestinal carbohydrate malabsorption in preruminating calves. Oral administration of 1.25 g of lactulose (a nonabsorbable carbohydrate)/kg to calves produced breath hydrogen concentrations significantly (P less than 0.001) higher than values determined after calves were fed milk and before the treatment was given. This indicates that, in the calf, fermentation of nonabsorbed carbohydrates results in increased breath hydrogen values. To induce small intestinal malabsorption, chloramphenicol was administered orally at 50 mg/kg, 2 times a day, to 5 calves for 3 days. Before therapy was started, each calf was fitted with a duodenal cannula to facilitate collection of intestinal mucosal biopsy samples during treatment. Chloramphenicol therapy significantly (P less than 0.001) increased breath hydrogen concentrations from those values measured after calves were fed milk alone. Concurrently, chloramphenicol administration significantly decreased intestinal villous length (P less than 0.001) and D-xylose absorption (P less than 0.05), compared with those values before treatment was given. These results demonstrate that decreased intestinal absorptive capacity is associated with an increase in breath hydrogen concentrations and that breath hydrogen may be useful in evaluating malabsorption in calves with naturally occurring enteric disease.  相似文献   

14.
Intestinal absorption of protein hydrolysis products: a review   总被引：27，自引：0，他引：27  
Many experimental techniques have allowed researchers to probe the fate of hydrolysis products from proteins in the small intestine. An overview of amino acid and peptide absorption from the small intestine is presented with attention given to historical perspectives that have led to current concepts. Speculation about nutritional significance of these processes is offered. Species differences exist in site of amino acid absorption. Numerous mechanisms are available for the transport of amino acids, including Na(+)-dependent carriers (energy-requiring), Na(+)-independent carriers and diffusion. The relative contribution each transport system makes to absorption is dependent on substrate concentration. Individual amino acids are not absorbed with equal efficiency; methionine usually is absorbed in the greatest proportion. There are interactions among amino acids for transports by specific transport systems. Small peptides (mostly di- and tripeptides) are absorbed from the small intestine more rapidly than are free amino acids; peptides are transported by systems independent of those responsible for transporting free amino acids. Evidence exists that the active transport of these peptides is via a proton gradient. Although the concept that peptides are absorbed intact into the circulation is not universally accepted, evidence supporting the possibility of tissue utilization of these small peptides is accumulating.  相似文献   

15.
125I-labeled immunoglobulin (Ig)G1 in colostral whey was used to determine the region of maximum absorption of Ig from the small intestine of the neonatal calf and the variation in Ig absorption among calves at the intestinal level. In experiment 1, 5 segments (approx 5%, 35%, 60%, 80%, and 95% of the duodenocecal length) were formed in the small intestine of 9 colostrum-deprived calves shortly after birth. These segments were injected with colostral whey containing 125I-IgG1 4 hours after birth, and uptake, transfer, and absorption (defined as uptake plus transfer) were determined for each segment 2 hours later. Raw data were adjusted for the milligrams of IgG1 injected per gram of intestinal tissue to obtain the least squares mean (LSM) value. The LSM values for absorption of IgG1 from distal segments 3, 4, and 5 were significantly greater (P less than 0.05) than those values for proximal segments 1 and 2. The region of the maximum IgG1 absorption was the lower small intestine, 60% to 80% of the duodenocecal length. There was also an indication of independence between uptake and transfer in each of the segments. Significant differences (P less than 0.05) were present among calves in the LSM values for uptake and absorption, but not for transfer. In experiment 2, thoracic ducts of 8 newborn calves were cannulated 4 to 5 hours after birth. At 6 hours after birth, colostral whey with 125I-IgG1 was injected into an intestinal segment (approx 60% to 80% of the duodenocecal length).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

16.
1. In an experiment on broiler cockerels, the influence of tannic acid (TA) and polyethylene glycol (PEG) on body weight gain (BWG), feed conversion ratio (FCR), weight of intestine and liver, the activities of serum enzymes LDH, AST, ALT and intestinal absorption function were investigated. 2. Broiler cockerels were given either a commercial diet alone (control group) or a commercial diet with TA (20 g/kg), PEG (10 g/kg) or TA plus PEG (20 + 10 g/kg), for 10 d. 3. On the last day of the experiment, all birds and remaining feed were weighed individually and a sample of blood was taken to measure the serum activities of lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The capacity of intestinal cells for the absorption of D-xylose was measured. Finally all birds were killed humanely and the intestine and liver were weighed. 4. The results showed that TA significantly reduced BWG and FCR, as well as the activity of LDH, AST and ALT. 5. TA also increased the relative weight of the intestine. Adding PEG alone had no effect on any of the measured parameters. 6. However, PEG improved significantly BWG, FCR and the activity of LDH and AST of TA-fed birds. 7. The plasma D-xylose concentration of experimental birds was similar for all dietary treatments most likely because of temporal separation between feeding the dietary TA and administering the D-xylose. 8. It was concluded that the presence of tannins in the GI lumen of the bird was necessary to affect the processes involved in the absorption of simple sugars such as D-xylose, at the level of intestinal absorptive cells.  相似文献   

17.
The absorption and the transportation of intestinally administrated bovine lactoferrin (LF) were immunohistochemically and physiochemically investigated in the small intestine of growing pigs. At the apical halves of the small intestinal villi, bovine LF was absorbed by transcytosis as small vesicles through villous columnar epithelial cells. The presence of bovine LF-positive membranes of transcytotic vesicles suggests that the absorption was mediated by LF-binding factors on the epithelial cell membranes. Almost all of the absorbed bovine LF was demonstrated to be transported via the lymphatics and the portal vein into the systemic circulation. The LF-concentration in systemic circulation was significantly higher at 1 hr following intestinal administration of bovine LF. Bovine LF-positive lymphocytes also were transferred into the systemic circulation from intestine via the lymphatics and the portal vein.  相似文献   

18.
Over a period of 4 days 15N-labelled lysine was infused into two growing female pigs (live weight approximately 50 kg) through a caecal cannula. The feeding was restrictive (1,400 g dry matter/day) and, with regard to lysine, it didn't meet the requirement. In a 7-day experiment the N- and 15N-content was measured periodically in the excretions (feces and urine), in various fractions of the blood and in selected slaughtering samples. From the infused 15N 3-5% are excreted as lysine in feces, another 5% are in other amino acids of the bacteria protein. The disappearance rate of 15N' from the large intestine makes greater than or equal to 90%. The biggest part of this 15N (78-88%) is excreted with the urine in form of 15N-urea. Obviously the infused amino acid is decomposed to NH3 in the large intestine and then absorbed. The absorbed ammonia is changed into urea in the ornithine cycle and excreted in urine. The recovery rate of the 15N infused as 15N-lysine is 93 and 84% resp. Incorporation of 15N in to serum protein or other body protein could not be detected so that the remaining difference of 7-16% cannot necessarily be interpreted as incorporation rate of 15N into the body protein. Under practical conditions the maximal utilisation of lysine from the feed in the large intestine is 1.6% and should thus be without importance.  相似文献   

19.
Two cats with intestinal malabsorption developed a hemorrhagic diathesis. Although unsubstantiated, the probable cause of bleeding was a chronic malabsorption of fat and the fat-soluble vitamin K. When treated with vitamin K1 per os, one cat's clotting times were only partially corrected. Since vitamin K1 is actively absorbed in the proximal small intestine, the incomplete response of this case to orally administered vitamin K1 was predictable. The infrequent occurrence of bleeding in animals with malabsorption is, in part, attributable to the ileal and colonic absorption of bacterially derived vitamin K2. For this reason, nonspecific use of antibiotics in these animals is contraindicated. Since long-chain, polyunsaturated fats impair vitamin K absorption, dietary fat given to animals with malabsorption should be restricted to medium- and short-chain, saturated fats. Vitamin K should be administered subcutaneously to these animals if prolonged clotting times or active bleeding is present, and routinely prior to surgery. Oral supplementation with vitamin K3, which is absorbed in the colon and less lipid soluble than vitamin K1, should be given to animals with malabsorption that are maintained as outpatients. Adequate dosage levels of vitamin K3, however, are yet to be established for the cat, and dose-dependent hemolytic anemia is a probable toxic manifestation.  相似文献   

20.
Tropical Animal Health and Production - The objective of this study was to compare the use of an external marker titanium dioxide (TiO2) as an alternative to chromic oxide (Cr2O3) in dairy cows....  相似文献   

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