Studies on nutrient digestibilities (pre-caecal and total) in pancreatic duct-ligated pigs and the effects of enzyme substitution

Introduction Exocrine pancreatic insufficiency causes digestive disturbances in humans and animals. However, although clinical symptoms of pancreatic insufficiency, e.g. steatorrhoea, only occurs after loss of 80–90% normal pancreatic secretory capacity (D i M agno et al. 1973), pancreatic enzyme supplementation does not always result in normalization of digestion (especially of fat), even with high doses of enzymes (L& ouml ; ser and F& ouml ; lsch 1995). In order to better understand the physiological and the pathological consequences of exocrine pancreatic insufficiency in humans as well as its therapy with enzyme substitution, studies have been made using an animal model of induced pancreatic exocrine insufficiency. Hither to, studies concerning pancreatic duct ligation and/or the influence of enzyme substitution have mainly been focused on estimation of enzyme activities in chyme (e.g. A bello et al. 1989) and/or on faecal analyses of total digestibility (e.g. I mmondi et al. 1972). To get more information on effects of enzymes (natural or substituted) it seems necessary to investigate the site and extent of digestion more intensively (S udendey 1995). Therefore a pig model of induced pancreatic exocrine insufficiency, via pancreatic duct ligation, was chosen and pre-caecal digestibility was measured by means of an ileo-caecal re-entrant fistula. Studies on the digestibility of a high fat diet were made, since cystic fibrosis patients with exocrine pancreatic insufficiency are recommended to take in high amounts of energy to avoid catabolic metabolism and nowadays these high energy diets comprise increasing proportions of fat (D urie and P encharz 1989; S hepherd et al. 1991). The following aspects were investigated in controls and pancreatic duct-ligated pigs that were fed a high fat diet: changes in the composition of ileal chyme and faeces; effects on nutrient digestibility (pre-caecal and total); efficacy of enzyme substitution in total exocrine pancreatic insufficiency.     

Exocrine pancreatic secretion in pigs fed sow's milk and milk replacer, and its relationship to growth performance

The objective of this study was to quantify and compare the effects of sow's milk and 2 milk replacer diets (containing clotting or non-clotting protein sources) on exocrine pancreatic secretion, plasma cholecystokinin, and immunoreactive cationic trypsin in pigs. In addition, the relationship between exocrine pancreatic secretion and growth in milk-fed pigs was studied. In a changeover experiment, 9 chronically catheterized pigs of 6.6 +/- 0.19 kg of BW were studied for 3 wk. Pigs were assigned to each of 3 diets. Exocrine pancreatic secretion was measured from the third to the seventh day on each diet. The protein content and trypsin activity of the pancreatic juice were measured. Blood samples were taken at 10 min before and after milk ingestion and were analyzed for cholecystokinin and immunoreactive cationic trypsin. Pancreatic protein and trypsin secretion did not differ between pigs fed sow's milk and those fed milk replacer, but the volume secreted was less for the pigs fed sow's milk (0.75 vs. 1.03 mL x kg(-1) x h(-1); P < 0.01). A postprandial response to milk intake was not observed. The 2 milk replacer diets did not affect exocrine pancreatic secretion differently. The average exocrine pancreatic secretion (volume, 0.94 mL x kg(-1) x h(-1); protein, 4.28 mg x kg(-1) x h(-1); trypsin, 1.65 U x kg(-1) x h(-1)) was intermediate between literature values for suckling and weaned pigs. Plasma cholecystokinin was elevated (approximately 18 pmol x L(-1)) and showed low correlations with the pancreatic secretion traits. Plasma immunoreactive cationic trypsin was not significantly related to any of the pancreatic secretion traits and should therefore not be used as an indicator for exocrine pancreatic function in milk-fed pigs. Exocrine pancreatic secretion varied substantially among individual pigs (protein, 0.22 to 13.98 mg x kg(-1) x h(-1)). Pancreatic protein and trypsin secretion showed a positive, nonlinear relationship with performance traits. It was concluded that neither specific sow's milk ingredients nor the protein source are responsible for a low pancreatic protein secretion in suckling pigs. Exocrine pancreatic secretion was positively correlated with ADG in pigs at an identical milk intake.     

Relations between body weight, feed intake, daily weight gain, and exocrine pancreatic secretion in chronically catheterized growing pigs

The aim of this investigation was to develop models that would make it possible to correct exocrine pancreatic secretion data for the effect of BW and feed intake in growing pigs. In addition, the significance of exocrine pancreatic secretion for daily weight gain (DWG) was studied. Data were used from 10 pigs (16 to 32 kg BW) surgically fitted with chronic pancreatic catheters. The samples were collected under controlled conditions for two to five experimental days per animal (a total of 39 observations), during 2 h preprandially and during 2 h when feeding (postprandially). The exocrine pancreatic secretion traits included the hourly output of volume, the amount of protein, and trypsin and amylase activities. Multiple linear regressions were used to develop models to describe exocrine pancreatic secretion. The individual pig was the most important source of variation in the model. With increasing BW, 7 out of 10 pigs showed an increase in exocrine pancreatic secretion. However, the slopes of the regression lines differed between animals, which made it impossible to develop general models for the correction of secretion data for the effect of BW. Postprandial exocrine pancreatic secretion was always higher than preprandial secretion, but the amount of feed intake per se did not seem to affect secretion. Exocrine pancreatic secretion and DWG were positively correlated. We concluded that, under the present circumstances, expressing secretion per kilogram BW or kilogram feed intake was not feasible. Expressing secretion per hour was the best way to present the data.     

The effect of feeding time (day versus night) and feeding frequency on pancreatic exocrine secretion in pigs

The effect of night feeding and feeding frequency on exocrine pancreatic secretion was studied in five chronically catherized growing pigs (16 to 31 kg). Feeding during the night (2200 to 2400 h) as compared to the day (1000 to 1200 h) tended to stimulate cholesterol ester lipase activity and tended to lower the colipase : lipase ratio in the pancreatic juice, but no effect on volume output, protein output and the activities of trypsin, chymotrypsin, amylase, lipase and colipase could be demonstrated. Feeding 12 small meals between 0800 and 2000 h as compared to one large meal (1000 to 1200 h) daily, altered the pattern of exocrine pancreatic secretion, tended to stimulate protein output by 44 %, chymotrypsin activity by 29 % and lipase activity by 46 %. These observations strengthened the theory that exocrine pancreatic secretion is partly regulated by feed intake per se and does not only depend on the amount of feed consumed. Feeding 12 small meals versus one large meal, compared at the same total daily feed intake, lowered the colipase : lipase ratio by 32 %. It can be concluded that feed intake pattern affected exocrine pancreatic secretion.     

Attempt to establish a chronic model to study the influence of bile and pancreatic juice diversion on pancreas feedback regulation in conscious pigs

The diversion of pancreatic juice and bile stimulates pancreatic exocrine secretion but the mechanism behind this process is still not clear. The present study investigates the influence of long lasting (10 h) bile diversion or pancreatic juice and bile diversion on the pancreatic secretion in conscious pigs. The experiments were performed on 4 weaned piglets, which had a catheter inserted to the accessory pancreatic duct and bile duct and two cannulas to the duodenum. The depletion of bile alone or both bile and pancreatic juice (PJ) resulted in an increased preprandial pancreatic juice outflow, as compared to controls. Bile diversion increased the pancreatic response to feeding. PJ volume, protein outflow, and trypsin activity values were significantly higher in bile diverted pigs than in control pigs during the prandial and postprandial periods. While in pancreatic juice and bile diverted piglets the PJ protein outflow and trypsin activity slightly increased in response to feeding, their values were lower than those of the control piglets. In conclusion, both pancreatic juice and bile present in the small intestine play an important role in the regulation of the pancreatic juice secretion.     

Serum pyruvate kinase and its relation to stress susceptibility in pigs

SUMMARY: Four blood tests, complementary to the halothane test, have been screened for their capacity to discriminate between homozygous and heterozygous stress resistant and stress susceptible pigs: TBARS in plasma, lipid peroxides from erythrocytes and plasma creatine and pyruvate kinase activity. Blood samples were collected from homozygous (NN) and heterozygous (Nn) stress resistant and homozygous stress susceptible (nn) pigs, while subjected to the halothane test. Serum creatine kinase and pyruvate kinase tests were retained for a more elaborated study. Pyruvate kinase appears to be a more reliable indicator of stress susceptibility than the well-known creatine kinase. However both parameters display a considerable standard deviation. Consecutive assays show the pyruvate kinase activity to be dependent on age (weight), which accounts for part of the variation; other sources of variation are the conditions of the exeriment and the way the imposed stress is perceived by the animal. During this experiment a rapid and accurate DNA-test for HAL-genotype detection has been developed (Fujii et al. 1991; Otsu et al. 1991; Coppieters et al. 1992). In spite of this, the pyruvate kinase parameter is a much more discriminating and remarkable indicator for stress susceptibility than the, in previous years, widely used creatine kinase test. ZUSAMMENFASSUNG: Serum Pyruvat Kinase und seine Relation mit Streβanf?lligkeit bei Schweinen Vier Blutteste, komplement?r dem HAL-Test, wurden in einem Screening-Verfahren untersucht um homozygote und heterozygote stre?resistente und stre?anf?llige Schweine zu differenzieren: TBARS in Plasma, Lipid Peroxyde von Erythrocyten und Plasma Kreatine und Pyruvat Kinase Aktivit?t. W?hrend des Halothantestes wurde Blut entnommen von homozygoten (NN) und heterozygoten (Nn) stre?resistenten und homozygoten stre?anf?lligen Schweinen (nn). Mit Serum Kreatine Kinase und Pyruvat Kinase Aktivit?t Tests wurden eine umfassende überprüfung durchgeführt. Letztere zeigt sich als ein zuverl?ssiger Indikator der Stre?anf?lligkeit als die wohl bekanntere Kreatine Kinase. Mehrmalige Analysen zeigen, da? Pyruvat Kinase Aktivit?t vom Alter (Gewicht) abh?ngig ist, was teilweise die Variabilit?t verursacht; andere Quellen der Variabilit?t sind die experimentellen Umst?nde und die Weise, wie der auferlegte Stre? durch das Tier erfahren wird. W?hrend der Durchführung dieses Experimentes wurde ein schneller und akkurater DNA-Test für HAL-Genotyp Detektion entwickelt (Fujii et al. 1991; Otsu et al. 1991; Coppieters et al. 1992). Im Vergleich mit dem, in vorgehenden Jahren, h?ufig angewendeten Kreatine Kinase Test, ist der Pyruvat Kinase Parameter trotzdem ein bemerkenswerter und diskriminierender Indikator für Stre?anf?lligkeit.     

Effects of surgical catheterization and degree of isolation on the behavior and exocrine pancreatic secretion of newly weaned pigs

The purpose of this study was to examine the effects of surgery and isolation on behavior and exocrine pancreatic secretion of nursery pigs. Thirty-two pigs were weaned at 28 d (d 0) of age and assigned to one of four treatments that comprised the 2 x 2 factorial combination of surgery (surgically modified, intensively handled animals or intact, minimally handled animals) and isolation (fully or partly isolated). The pigs were kept in metabolic crates that provided full or partial isolation for 25 d after weaning. On d 3, one-half of the fully and partly isolated pigs were surgically fitted with a pancreatic catheter, whereas others were left intact. Exocrine pancreatic secretions were collected from catheterized pigs beginning on d 7 and continuing every 2nd d. Behavior of the pigs was video-recorded on d 6 and 13 from 0700 to 2230. There was no indication of treatment effects on the exocrine pancreatic secretion. The volume of pancreatic secretion increased from d 5 to 23, and during the same period the output of protein and enzyme activity also increased. Surgically catheterized pigs showed a passive behavioral response in their undisturbed behavior, characterized by less time spent active, fewer postural changes, less chain manipulation, fewer escape attempts, and less play behavior than their intact littermates. Furthermore, surgical catheterization led to less fear of humans and behavioral indications of an ability to distinguish between familiar and unfamiliar persons. Partial isolation led to increased activity, increased chain manipulation, and increased play behavior, indicating that the provision of limited social contact may help reduce the negative effects of individual housing in weaned pigs. These results suggest that it is important to be aware of effects of housing, experimental surgery, and associated handling when interpreting results from intensive experiments.     

Evidence of a specific dietary selection for lysine by the piglet

The ability of animals to appropriate sources of food and select among them to obtain a nutritionally adequate diet that is best suited for their physiologic status has been examined in numerous species, but considerable research has addressed self-selection trials with chicks. Observations on diet preference have led to the assumption that birds have an innate ability to regulate their intake of macro- and micronutrients, and that they can do so with a considerable degree of precision (e.g. Holcombe et al. 1975, 1976; Elkin et al. 1985; Harper and Peters 1989; Emmerson et al. 1991; Steinruck et al. 1991a,b; Steinruck and Kirchgessner 1993a,b,c; Shariatmadari and Forbes 1993; Forbes and Shariatmadari 1994, 1996). Experimental evidence also shows that domesticated pigs which are offered a choice between two diets will select a diet containing an adequate amount of protein in preference to one that is deficient in protein, or will select specific proteins among various protein sources (Robinson 1974; Kyriazakis et al. 1990; Kyriazakis and Emmans 1992, 1993; Bradford and Gous 1992; Roberts and Azain 1997). The characteristic amount of a specific protein selected by the animals appeared to be related to the quality of the protein source. This was obvious from a few amino acid selection studies showing that growing-finishing pigs have the ability to select preferentially amino acid-adequate diets over amino acid-deficient diets within a few days (Devilat et al. 1970; Robinson 1975a,b; Davey 1978; Henry 1987, 1993). In contrast, there are also some exceptions to the hypothesis that selection of diet is related to the nutritional quality of the protein fed (Ashley and Anderson 1975). However, some of those studies are not conclusive due to changes in preferences by the animals over time and differences in protein source, palatability and amino acid pattern between the test diets. Since, an investigation of a self-selection behaviour by piglets has rarely been studied in detail, the purpose of this research was to determine whether piglets that are given a choice of diets with high or low lysine contents can regulate the intake of each to optimize lysine intake and performance. The objectives of this study were to determine the preference of piglets for diets varying in lysine content and to determine whether the preferences for these diets change with time. This indispensable amino acid was selected for study because it is first limiting in conventional diets for growing pigs.     

Whole-body protein turnover and nitrogen balance in growing pigs supplied with an antibiotic feed additive (Avilamycin)

Introduction   Antibiotic feed additives like Avilamycin (Maxus^®) exert a well-documented stimulatory effect on growth rate and feed efficiency in pig production (reviewed by, e.g., R oth and K irchgessner 1990; K amphues and M eyer 1992). The benefits to production performance seem to originate mainly from an enhanced gain of body protein as has been demonstrated in nitrogen balance trials with piglets and fattening pigs (R oth and K irchgessner 1993a,b; W indisch et al. 1998). However, the primary mode of action of antibiotic feed additives is not clarified completely. The growth-stimulating effect is assumed to originate from an enhanced absorptive capacity of the digestive tract for essential nutrients due to an improved microbial ecosystem in the gut (reviewed by, e.g., G reife and B erschauer 1988). However, metabolic effects may contribute to the higher protein accretion capacity also, as for example a reduced immune defense stress at the small intestine for example (discussed by, e.g., S chole et al. 1985). In order to elucidate possible metabolic effects of antibiotic feed additives it was the aim of the present study to combine a nitrogen balance experiment on Avilamycin-treated growing pigs with measurements on whole-body protein turnover.     

Ileal exposure to pig pancreatic juice and bile inhibit exocrine pancreatic secretion in pigs

The mechanisms involved in the down regulation of the exocrine pancreas are still not fully elucidated. The purpose of the present study was to examine the effect of duodenal and ileal exposure to pancreatic enzymes and bile on pancreatic secretion. Experiments were performed with pigs fitted with pancreatic duct, ileal and jugular vein catheters, and duodenal T-shaped cannula. A negative feedback regulation of pancreatic secretion was found for both duodenal and ileal delivery of pancreatic juice. Pancreatic secretion was unaffected by duodenal delivery of bile and bile salts, while ileal delivery of bile and bile salts lowered it. On the other hand, pancreatic secretion was increased by duodenal loading of commercial non- or activated pancreatic enzyme preparations, thus probably recognised as dietary protein. Plasma cholecystokinin (CCK) level was lowered only by duodenal delivery of pancreatic juice. In conclusion, the results prove the existence of negative feedback mechanism regulating pancreatic secretion dependent on the presence of pure pancreatic juice or bile at the ileal level. The mechanism at the duodenal level is exclusively sensitive to pure pancreatic juice.     

The Effect of Blood Sampling on Plasma Cortisol in Female Reindeer (Rangifer tarandus tarandus L)

A major response of the body to stress is the secretion of adrenocorticotrophic hormone (ACTH) by the adenohypophysis resulting in increased blood Cortisol levels. Corticotropin releasing factor (CRF) controls the release of ACTH, mediating a direct effect at the level of the pituitary (Guillame et al. 1992). An animal''s perception of a stressful event and the resulting increase in Cortisol production can be influenced by previous experience, season, time of day, and the animal''s sex, age, and condition (Dantzer & Mormède 1983, Moberg 1985).     

胰腺外分泌功能调节的研究进展

胰腺外分泌(主要指胰液)对食物的消化、吸收起着十分重要的作用。胰液分泌紊乱会导致动物消化、吸收异常,影响动物生长发育,给生产带来很大损失。影响胰腺外分泌的因素很多,主要包括以迷走神经为主的神经调节和以激素为主的体液调节。在神经和体液综合调节下,使得胰液分泌维持在一个正常水平,确保动物的生长发育。除这些自身调节机制外,还有很多外界因素影响其分泌。健脾消食类中药因其具有健脾益气、助消化、促生长的作用,在临床应用较多。因此,有必要了解这些中药对胰腺外分泌的调节作用。文章从神经、体液及中药调节方面综述了胰腺外分泌诸因素,为进一步研究和开发健脾消食中药添加剂提供理论基础。     

Zum Einfluss des Reifestadiums von Maispflanzen und des Einsatzes von Milchsäurebakterien bei ihrer Einsilierung auf die Nährstoffumsetzungen im Verdauungstrakt von Milchkühen

Einleitung
Der Einsatz qualitativ hochwertiger Grundfuttermittel ist eine wesentliche Voraussetzung für eine bedarfsgerechte Nährstoffversorgung hochleistender Milchkühe. Von besonderer Bedeutung ist hierbei Maissilage. Da diese einen relativ hohen Gehalt an Stärke aufweist, die zudem im Vergleich zu anderen Getreidestärken nur in geringerem Umfang im Pansen abgebaut wird (C hase 1993; H untington 1997; L oose et al. 1998), kann durch sie die Menge an Stärke, die das Duodenum erreicht, gesteigert und somit die Energieversorgung aus dem Grundfutter deutlich erhöht werden. Bisher ist jedoch weitgehend unklar, inwiefern die Maisreife und die damit verbundenen Änderungen im Stärke- und Rohfasergehalt der Maispflanze auch die ruminale Abbaubarkeit der Stärke und somit die postruminale Stärkeanflutung am Duodenum beeinflussen. Ebenso sind die Ergebnisse aus den bisher noch wenigen Untersuchungen zum Einfluß einer Beimpfung von Maispflanzen mit Milchsäurebakterien (MSB) vor der Silierung noch recht widersprüchlich. So beobachteten zum Beispiel C leale et al. (1990) eine um 5,2%-Punkte verbesserte Verdaulichkeit der organischen Substanz, wenn die Maispflanzen vor der Einsilierung beimpft worden waren gegenüber der unbeimpften Variante. L eahy et al. (1988) konnten dagegen keine Effekte einer MSB-Beimpfung auf den Futterwert von Maissilage feststellen. Deshalb sollte es das Ziel der vorliegenden Arbeit sein zu ermitteln, welchen Einfluß zum einen der Reifegrad der Maispflanzen und zum anderen die Beimpfung des Siliergutes mit lebenden Milchsäurebakterien auf den Futterwert der hieraus hergestellten Maissilage haben. Hierzu wurde in den durchgeführten Untersuchungen der Einfluß der Silagen auf pansenphysiologische Kenndaten, den ruminalen Stärke- und Rohfaserabbau, die postruminale Nährstoffanflutung sowie die Rohnährstoffverdaulichkeit bestimmt.     

Die Wirkung einer Vitamin-A-Zulage auf die Konzentration einzelner antioxidativer Komponenten und die Antioxidative Kapazität im Serum von Ponys

Einleitung
Das Plasma enthält wenige antioxidative Enzyme, ist aber reich an anderen hoch- und niedermolekularen antioxidativen Molekülen. Hier sind die Plasma-Proteine mit ihren Thiolgruppen, allen voran Albumin, zu nennen. Von den niedermolekularen Verbindungen haben Urat, Ascorbat, Thiole, Bilirubin und α-Tocopherol eine Bedeutung. Als Parameter für die oxidative Homöostase des Organismus kann die Bestimmung der antioxidativen Kapazität des Plasmas und anderer biologischer Flüssigkeiten herangezogen werden (L ewin and P opov 1994). In den letzten Jahren wurde eine Vielzahl von Methoden zur Bestimmung der Antioxidativen Kapazität von Einzelsubstanzen und biologischem Material entwickelt. Die Generation freier Radikale geschah photochemisch (P opov and L ewin 1994), chemisch oder chemisch-enzymatisch (P ascual and R omay 1992). Die antioxidative Wirkung wurde dann über Radikal-Spintrapping (S oriani et al. 1994), Fluoreszens (R-Phycoerythrin) oder Chemilumineszenz (Luminol) ermittelt.
Die genannten Verfahren haben bisher kaum Eingang in die Tiermedizin gefunden, obwohl eine Reihe metabolischer Dysfunktionen bei Haustieren mit Störungen des peroxidativen Stoffwechsels in Zusammenhang gebracht werden (F uhrmann et al. 1996; M udron et al. 1997; S allmann 1998).
Ein weiterer Aspekt der Antioxidativen Kapazität ist die bei einigen Spezies beschriebene verminderte Vitamin E-Retention bei hohen Gaben von Vitamin A (Huhn: C ombs 1976; F rigg and B roz 1983; Ratte: J enkins and M itchell 1986; Schwein: H oppe and S ch & ouml ; ner 1993). Demzufolge erhob sich die Frage, ob auch beim Pony eine überhöhte Gabe von Vitamin A die Tocopherolgehalte und damit den antioxidativen Stoffwechsel negativ beeinflußt. Dazu wurden neben einzelnen antioxidativen Komponenten die Antioxidative Kapazität des Serums mit zwei unterschiedlichen Methoden bestimmt.     

The effect of an oxidized dietary oil on plasma cholesterol and thyroid hormone concentrations in miniature pigs fed on a hyperlipidaemic diet

Introduction Polyunsaturated fatty acids (PUFA) are labile compounds which under the promoting effect of oxygen, high temperature or metallic catalysts undergo peroxidative damage. In the course of lipid peroxidation, several primary and secondary products such as peroxides, aldehydes, dimers or polymers are formed. Human western diets are not only generally rich in fats, but also rich in fats that have been subjected to various degrees of processing and heat treatment, particular deep fat frying. The absolute intake of lipid peroxidation products in western countries varies over a wide range, depending on the individual eating habits; however, it can be assumed that on average of the population at least 50% of the fat consumed has been heated during industrial processing of foods or preparing of meals. Therefore, the potential toxic effects of products formed from polyunsaturated fatty acids during heating or frying of fats are of particular interest for human health, particularly in the development of coronary heart disease. In literature, there is one study which reports that the development of atherosclerosis is accelerated by dietary oxidized lipids in cholesterol-fed rabbits (S trapans et al. 1996). The reason for this observation, however, is not clear. The pathogenesis of atherosclerosis is very complex. Undoubtedly, the concentration of cholesterol in plasma and in lipoproteins as well as the susceptibility of low-density lipoproteins to lipid peroxidation are major factors influencing the risk of coronary heart disease (S teinberg et al. 1989; M archioli et al. 1996). In order to clarify a potential relationship between the intake of dietary oxidized lipids and an increased risk of coronary heart disease, this study investigated the effects of feeding oxidized oils on the concentrations of lipids in plasma and lipoproteins and the susceptibility of plasma lipids to peroxidation (S taels et al. 1990; T anis et al. 1996). The concentrations of thyroid hormones in plasma were measured because they are in close relationship with the plasma cholesterol concentration. Miniature pigs that were fed a cholesterol-enriched diet were used in this study because they have been described to be an adequate model for the investigation of the lipid metabolism in humans (B arth et al. 1990). A general problem in the investigation of the effects of dietary oxidized lipids is that the administration of a diet containing highly oxidized fats reduces food intake, food efficiency and the digestibility of fatty acids (C orcos benedetti et al. 1987; Y oshida and K ajimoto 1989; B lanc et al. 1992; H ayam et al. 1993; B orsting et al. 1994; L iu and H uang 1996; H ochgraf et al. 1997). Moreover, because of strong oxidation, highly oxidized oils usually contain significantly less PUFA and tocopherols than the equivalent fresh oils (D& rsquo ; aquino et al. 1985; C orcos benedetti et al. 1987; B lanc et al. 1992; B orsting et al. 1994; H ayam et al. 1995; L iu and H uang 1995; H ochgraf et al. 1997). In order to avoid these problems a controlled feeding system was used in this study and dietary fats were equalized for their fatty acid composition and tocopherol concentrations. Studies from literature reported that dietary oxidized oils reduce tocopherol concentrations and thereby alter the fatty acid composition of tissues and increase the fragility of erythrocyte membranes in animals (C orcos B enedetti et al. 1987; Y oshida and K ajimoto 1989; B lanc et al. 1992; H ayam et al. 1993). However, as mentioned above, in most of the studies reported in literature, the concentration of vitamin E was significantly lower in diets containing oxidized oils than in control diets. In order to find out whether those effects are also observed if diets are adjusted for identical vitamin E activities, this study also measured the tocopherol concentration in plasma, the fatty acid composition of erythrocyte lipids and the osmotic fragility of erythrocytes.     

Free amino acids in plasma of neonatal calves are influenced by feeding colostrum for different durations or by feeding only milk replacer1

Introduction Newborn development is characterized by high protein synthesis and nitrogen (N) turnover rates in many tissues, especially in the gastrointestinal (GI) tract (G oldspink and K elly 1984; Y oung et al. 1988; S immen et al. 1990; X u 1996). Colostrum provides particularly large amounts of nutrients (especially proteins) and immunoglobulins as well as non-nutrient growth-promoting factors; it therefore plays a major role in the development of the neonatal gut, especially protein synthesis, and other organs, as shown in several species including cattle (B erseth et al. 1983; P atureau M irand et al. 1990; C ampana and B aumrucker 1995; O dle et al. 1996; X u 1996; B urrin et al. 1997). Rates of body protein synthesis and N turnover were greater during enteral than during parenteral feeding, indicating considerable involvement of the GI tract in protein metabolism (D uffy and P encharz 1986). Protein components in colostrum provided about 35% of amino acids (AA) in newborn lambs, suggesting that amounts of ingested protein with colostrum greatly influence the AA status of the neonate (Y von et al. 1993). Glutamine and glutamate are the most abundant AA in bovine milk protein (M eijer et al. 1993) and glutamine is of special interest for postnatal gut development (S ouba 1991; K imura 1996; H eird 1998). The glutamine:glutamate ratio was markedly changed in neonatal calves (D emign & eacute ; and R& eacute ; m & eacute ; sy 1979) after colostrum intake. Recently, we have demonstrated that gut growth and absorptive capacity of the intestine, as well as metabolic and endocrine changes in newborn calves, are greatly dependent on amounts of ingested colostrum (H ammon and B lum 1997, 1998; B& uuml ; hler et al. 1998). Based on that AA absorption, metabolism and status may be influenced by amounts of fed colostrum. Therefore in this study we have tested the hypothesis that feeding colostrum for different durations, or feeding only milk replacer, affects plasma protein and free AA concentrations during the first week of life in calves.     

Effect of prenatal stress on subsequent response to mixing stress and a lipopolysaccharide challenge in pigs

Sows subjected to prenatal stress have been found to produce offspring that have altered responses to stress. Our objective was to determine if exposing a sow to stress would alter the response of the offspring to lipopolysaccharide (LPS) at 2 mo of age or their response to mixing stress at 4 mo of age. Sow treatments consisted of intravenous injections of ACTH (1 IU/kg of BW), exposure to rough handling for a 10-min duration (rough), or no treatment (control) once per week from d 42 to 77 of gestation. At 2 mo of age, pigs from each treatment, 1 per litter (n = 21, 17, and 15 for the ACTH, rough, and control treatments, respectively), were challenged with 2 μg of LPS/kg of BW or saline, or served as a noninjected control. Their behavioral response to a human approach test and salivary cortisol were measured. At 4 mo of age, 1 pig from each treatment (n = 14, 14, and 15 for the ACTH, rough, and control treatments, respectively) was taken from its home pen and placed in a pen of unfamiliar pigs. At this time, a punch biopsy wound (6 × 6 mm) was created to measure the ability of the pig to heal the wound. At this same time, each pig received a 1-mL intramuscular injection of 20% ovine red blood cells (oRBC), and then a second injection of oRBC at 21 d postmixing. Blood samples were collected 3 times per week for 2 wk and then once a week for 4 more weeks. Blood samples were analyzed for cortisol, porcine corticosteroid-binding globulin, antibody response to oRBC, and nitric oxide production by macrophages. Behavior was recorded during the first 5 d after mixing. All pigs in the LPS challenge responded with characteristic sickness behavior; however, pigs in the rough treatment showed less sickness behavior than those in the other 2 treatments (P < 0.05). Maternal stress treatment did not affect (P < 0.43) salivary cortisol. Pigs from all treatments responded similarly to mixing stress with regard to cortisol, porcine corticosteroid-binding globulin, antibody titers, nitric oxide production, and hematology measures, and all pigs experienced the same amount of aggression in response to mixing. Without altering peripheral measures of stress responsivity, prenatal stress enhanced the ability of pigs to cope with a simulated immune challenge, which could prove to be an adaptation to challenging environments.     

Stress and its influence on reproduction in pigs: a review

The manifestations of stress, defined as a biological response to an event that the individual perceives as a threat to its homeostasis, are commonly linked to enhanced activity of the hypothalamo-pituitary-adrenal (HPA) axis and the activation of the sympathetic adreno-medullary (SA) system. Activation of the HPA system results in the secretion of peptides from the hypothalamus, principally corticotropin releasing hormone (CRH), which stimulates the release of adrenocorticotropic hormone (ACTH) and beta-endorphin. ACTH induces the secretion of corticosteroids from the adrenal cortex, which can be seen in pigs exposed to acute physical and/or psychological stressors. The present paper is a review of studies on the influence of stressors on reproduction in pigs. The effects of stress on reproduction depend on the critical timing of stress, the genetic predisposition to stress, and the type of stress. The effect of stress on reproduction is also influenced by the duration of the responses induced by various stressors. Prolonged or chronic stress usually results in inhibition of reproduction, while the effects of transient or acute stress in certain cases is stimulatory (e.g. anoestrus), but in most cases is of impairment for reproduction. Most sensitive of the reproductive process are ovulation, expression of sexual behaviour and implantation of the embryo, since they are directly controlled by the neuroendocrine system.     

Pancreatic enzyme supplementation in normal and exocrine pancreatic insufficient pigs

The effect of pancreatic enzyme preparation (Combizyme Forte granulate) on the growth rate of normal, sham-operated and pancreatic duct ligated growing pigs was studied in 2 trials. In the first trial 6 normal Yorkshire pigs were fed a pancreatic enzyme supplement and 6 other pigs from the same litter were fed without supplementation. The growth rate over a period of 4 weeks was not significantly greater in the supplemented group. In a second trial exocrine pancreatic insufficiency, without diabetic symptoms, was produced in 12 pigs (aged 1.5 months and weighing 14 kgs) by ligation of the main pancreatic duct. The growth rates over a period of 20 days after surgery were 240 g, 454 g and 483 g/day in ligated pigs, in ligated pigs supplemented with pancreatic enzyme and in sham-operated control pigs, respectively. The difference between the ligated groups was significant (p less than 0.01) indicating the efficiency of the pancreatic enzyme therapy.     

Influence of intraduodenally infused olive and coconut oil on postprandial exocrine pancreatic secretions of growing pigs

The effect of dietary vegetable oils differing in fatty acid composition that were infused directly into the duodenum on exocrine pancreatic secretions in pigs has not previously been studied. The objective of the present study was to determine the acute response of the exocrine pancreas to vegetable oils with various fatty acid profiles under prandial conditions. Six growing pigs (BW 13.2 kg) were surgically prepared with pancreatic duct catheters and duodenal reentrant T-cannulas. The animals were fed twice a day (1000 and 1600) a commercial weaner diet at a rate of 2% of BW. Beginning with the morning feeding, olive oil, coconut oil, or saline as a control were infused in boluses every 5 min in total 0.1% of BW over a period of 1 h directly into the duodenum according to a 3 x 3 Latin square design. Pancreatic juice was collected over a period of 4 h, beginning 1 h preprandially (0900) until 3 h postprandially (1300). A time effect was observed after the infusion of olive oil on the volume of secretion, on protein contents and outputs, as well as on lipase contents and outputs and on colipase contents. The infusion of saline and coconut oil changed the runs of the curves for lipase and colipase outputs. No time x treatment interactions were observed regarding volume of secretion, protein contents and outputs, trypsin contents and outputs, and lipase outputs. The runs of the curves for lipase contents were different between the olive oil and saline treatment and between the olive oil and coconut oil treatment. The runs of the curves for the olive oil and saline treatment differed from each other regarding colipase contents. Pooled values of colipase outputs were elevated after coconut oil treatment, and a positive correlation between trypsin and colipase contents was found. Under prandial conditions, the exocrine pancreas responds differently in its acute secretion to different vegetable oils due to the differences in the fatty acid profiles.