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Biomedical subjects

A G Van Kessel

Publications and source records attributed to A G Van Kessel.

17 recordsLinked to original sources
PubMed2006

The effect of hen-egg antibodies on Clostridium perfringens colonization in the gastrointestinal tract of broiler chickens.

We evaluated the ability of hen-egg antibodies (HEA) to reduce intestinal colonization by Clostridium perfringens in broiler chickens. Antibodies against C. perfringens or cholera toxin (negative control) were obtained from the eggs of laying hens hyperimmunized using a C. perfringens bacterin or cholera toxin. Eggs were collected, pooled, and egg antibodies were concentrated by polyethylene-glycol precipitation. An initial experiment was conducted to determine the in vivo activity of the administered antibody along the length of the intestine. Thereafter, two feeding trials were performed to assess the efficacy of feed amended with the egg antibodies in reducing the level of colonization of C. perfringens in challenged birds. Antibody activity declined from proximal to distal regions of the intestine but remained detectable in the cecum. In the first experiment there was no significant reduction in the number of C. perfringens in the birds fed the diet amended with the anti-C. perfringens egg antibody, compared to the birds that received the anti-cholera toxin egg antibody (n=10), at any of the sampling times. In the second experiment there was a significant decrease in C. perfringens intestinal populations 72 h after treatment (n=15) as assessed by culture-based enumeration, but there was no decrease as measured by quantitative PCR based on the C. perfringens phospholipase C gene. Intestinal-lesion scores were higher in the birds that received the anti-C. perfringens HEA. Our work suggests that administration of HEA did not reduce the level of C. perfringens intestinal colonization and conversely might exacerbate necrotic enteritis.

Animal Feed↗
PubMed2006

Effects of commensal bacteria on intestinal morphology and expression of proinflammatory cytokines in the gnotobiotic pig.

A germ-free neonatal pig model was established to determine the effects of bacterial colonization by different species on small intestinal morphology and proinflammatory cytokine gene expression. Two experimental groups of 16 pigs were aseptically delivered by cesarian section and allocated into 4 gnotobiotic isolators. Pigs were either maintained germ-free (GF), or were orally inoculated with either a single strain of nonpathogenic Escherichia coli (EC) or Lactobacillus fermentum (LF) or conventionalized with adult porcine feces (CV). After 13 days tissue samples were collected at 5 regions corresponding to 5%, 25%, 50%, 75%, and 95% of the small intestine (SI) length. In Experiment 2, the GF isolator became contaminated with Staphylococcus epidermidis (SE). In general, intestinal responses to bacterial colonization were similar among GF, LF, and SE pigs, and intestinal responses in EC pigs were more similar to CV pigs. Responses to bacterial colonization were most pronounced in the distal SI regions (50%-95%), suggesting that nonmicrobial factors may be more important in the proximal SI. Relative to CV pigs, the distal intestines of GF, LF, and SE pigs were characterized by long villi, shallow crypts, increased relative intestinal mass, and decreased lamina propria cellularity, whereas SI morphology was intermediate in EC pigs. Relative expression of proinflammatory cytokines interleukin-1beta (IL-1beta ) and IL-6 generally increased distally in the SI and was highest in EC and CV pigs. We observed regional variation in SI morphology and proinflammatory cytokine expression, which differed with bacterial species. This study demonstrates that bacterial species differentially affect intestinal morphology and expression of proinflammatory cytokines and suggests that neonatal bacterial colonization patterns may have long-term effects on intestinal health and development.

Animals↗
PubMed2006

Effects of guar gum and cellulose on digesta passage rate, ileal microbial populations, energy and protein digestibility, and performance of grower pigs.

Dietary guar gum and cellulose were studied as purified soluble and insoluble nonstarch polysaccharide (NSP) sources, respectively. A control diet containing 14% cornstarch was formulated. A 7% guar gum, a 7% cellulose, and a 7% guar gum + 7% cellulose diet were formulated by adding the NSP to the control diet at the expense of cornstarch (wt/wt), forming a 2 x 2 factorial arrangement. The objectives were to determine whether guar gum and cellulose altered 1) the passage rate of digesta through the small intestine and total tract; 2) the digestibility of energy and CP, characteristics of the digesta, and microbial populations in the ileum; 3) plasma glucose and ghrelin concentrations; and 4) short-term voluntary feed intake and growth performance of grower pigs. In Exp. 1, 12 pigs (27.0 +/- 1.5 kg of BW) were fitted with an ileal T-cannula and were used in a 2-period change-over design, providing 6 observations per diet. Each period included 18 d: a 12-d acclimation period followed by 2-d feces, 3-d digesta, and 1-d venous blood collection periods. In Exp. 1, guar gum and cellulose slowed the passage rate of digesta through the small intestine by 26 and 18%, respectively (P < 0.05). Guar gum increased total tract retention time of the digesta by 14% (P < 0.05). Guar gum and cellulose increased the viscosity of ileal digesta by 72 and 76%, respectively (P < 0.05). Cellulose reduced ileal energy and CP digestibility (P < 0.05), but guar gum only tended to decrease ileal energy digestibility (P < 0.10). Guar gum and cellulose reduced total tract energy and CP digestibility (P < 0.05). At 60 min after feeding, guar gum decreased plasma glucose by 10% (P < 0.10). Guar gum interacted with cellulose to reduce plasma ghrelin before and after feeding (P < 0.05). Guar gum and cellulose interacted to increase ileal bifidobacteria and enterobacteria (P < 0.05); however, guar gum, but not cellulose, increased ileal clostridia (P < 0.05). In Exp. 2, 20 individually housed grower pigs (5 pigs per diet) had free access to the 4 diets used in Exp. 1 for 14 d. Guar gum and cellulose decreased ADG and reduced ADFI on d 0 to 14 (P < 0.05). In summary, increasing purified NSP in the diet reduced the passage rate of digesta, energy and protein digestibility, and feed intake, but increased ileal bifidobacteria and enterobacteria populations. The effects of cellulose were similar to those of guar gum. In conclusion, monitoring of dietary NSP is a critical factor to achieve predictable digestible nutrient intake and intestinal bacterial populations.

Animal Feed↗
PubMed2005

Dietary glycine concentration affects intestinal Clostridium perfringens and lactobacilli populations in broiler chickens.

Previous studies have reported that intestinal populations of Clostridium perfringens, the causative agent of necrotic enteritis (NE), are correlated with diets high in glycine. To establish a direct causative link, 3 trials were conducted to examine the effect of dietary glycine levels on gut populations of C. perfringens, alpha-toxin production, and NE lesion scores in broiler chickens. In trials 1 and 2, 12 groups of 4 birds were fed 4 different ideal protein-balanced diets formulated to contain 0.75, 1.58, 3.04, or 4.21% glycine from d 14 to 28 of age. In trial 3, 24 groups of 4 birds were given 6 different ideal protein-balanced diets formulated to contain 0.50, 0.75, 1.00, 1.50, 2.00, or 4.00% glycine. All birds were orally challenged with a broth culture of C. perfringens type A on d 1 and between d 14 and 21 of age and killed on d 28. The majority of birds showed clinical signs of NE with 4.16 to 8.33% mortality in the 3 trials. The highest mortality and intestinal lesion scores were observed in chickens receiving 3.04% glycine in trials 1 and 2, and 4.00% glycine in trial 3. Clostridium perfringens populations in the cecum varied quadratically with increasing dietary glycine, with the maximal response seen at 3.30,3.89, and 3.51% dietary glycine in trials 1, 2, and 3, respectively. Numbers of lactobacilli in cecum declined significantly (P < 0.05) with increasing levels of glycine. The results suggest that dietary glycine level has a significant effect on C. perfringens and lactobacilli populations and may be a predisposing factor for NE in broiler chickens.

Animals↗
PubMed2004

Effects of dietary protein source and level on intestinal populations of Clostridium perfringens in broiler chickens.

Two experiments were conducted to examine the effect of the level of dietary crude protein and protein source on intestinal populations of Clostridium perfringens in broilers. In experiment 1, 6 groups of 12 birds were fed diets containing 230,315 or 400 g/kg crude protein with soy protein concentrate (SPC) or low-temperature-dried fishmeal as the major protein sources in a 2 x 3 factorial arrangement of treatments. A significant interaction between protein source and level was observed where the number of C. perfringens present in the ileum and cecum increased as the level of crude protein in the diets increased from 230 to 400 g/kg in the birds fed fishmeal-based diets (P < 0.05) but not in the birds fed SPC-based diets. In experiment 2, the dietary treatments used were arranged in a 2 x 2 factorial arrangement with 2 levels of crude protein (230 and 400 g/kg) and 2 protein sources (SPC or fishmeal). The main effects of protein source and protein level significantly (P < 0.05) affected numbers of C. perfringens without interaction. Amino acid analysis of the diets showed that the glycine and methionine contents of the fishmeal diets were elevated compared with the SPC diets. This suggests that the level of crude protein, protein source, and amino acid content of diets affect the growth of C. perfringens in the lower intestinal tract of the broiler chicken and might be predisposing factors to outbreaks of clinical necrotic enteritis.

Amino Acids↗
PubMed2003

Absorption of methionine and 2-hydroxy-4-methylthiobutoanic acid in conventional and germ-free chickens.

The apparent absorption of 3H-labeled L-Met and L-2-hydroxy-4-methylthiobutoanic acid (MHA-FA) was compared in germ-free and conventional broiler chickens to determine the effect of intestinal bacteria on the absorption of Met and MHA-FA. The two diets contained 0.236% of added Met or MHA-FA. Nineteen germ-free birds were maintained in two isolators and fed diets that had been sterilized by gamma irradiation (50 kilogreys). Nineteen conventional birds were reared in batteries and received nonirradiated feed. Diets were fed ad libitum for 3 wk. On d 21 of the experiment, the birds fasted overnight and were refed the experimental diets to which 1.11 x 10(7) Bq of 1-[methyl3H]MHA-FA or 1-[methyl3H]Met/kg of feed had been added. 51CrCl3 (1.11 x 10(7) Bq/kg of feed) was added as an indigestible marker. After 3 h the birds were euthanized, and their intestinal tracts were removed and partitioned into six sections. Residual Met and MHA-FA in digesta were calculated as the ratio of 3H:51Cr in each sample divided by the ratio of 3H:51Cr in the feed. The residual MHA-FA in the distal ileum of germ-free broilers was lower than in conventional birds (4.7 and 10.2% respectively; P < 0.05). In contrast the residual Met in the distal ileum of germ-free broilers was not different than in conventional birds (3.0 and 3.7% respectively; P > 0.05). This study demonstrates that intestinal bacteria significantly reduce the apparent absorption of MHA-FA from the intestinal tract of broiler chickens.

Animal Feed↗
PubMed2003

Hot topic: an association between a leptin single nucleotide polymorphism and milk and protein yield.

Allelic variation (C to T transition that results in an Arg25Cys) in the leptin gene has been associated with increased fat deposition in beef cattle. We report that this same genetic variant is also present in dairy breeds. Body fat reserves play an important role in sustaining high milk production in early lactation, when energy intake is limited. To test for an association between the leptin single nucleotide polymorphism and milk productivity, we genotyped 416 Holstein cows and compared lactation performance data using a mixed model. Animals homozygous for the T allele produced more milk (1.5 kg/d vs. CC animals) and had higher somatic cell count linear scores, without significantly affecting milk fat or protein percent over the entire lactation. The increase in milk yield is most prominent in the first 100 d of lactation (2.44 kg/d), declining to 1.74 kg/d between 101 and 200 d in lactation. The milk yield advantage, observed in cows homozygous for the T allele, could represent a major economic advantage to dairy producers.

Alleles↗
PubMed2000

Evaluation of site and age of weaning on pig growth performance.

Site-segregated early weaning (SSEW) refers to the practice of weaning pigs from the sow at an early age and placing them in a nursery that is physically isolated from the breeding herd. An experiment involving 369 pigs was conducted at the Prairie Swine Center to investigate the impact of SSEW on pig performance when the herd of origin has a high health status and when housing and management conditions are kept as similar as possible across weaning regime. Three treatments were compared: weaning at 21+/-3 d and keeping the pigs on-site in an all-in-all-out nursery room (Control), weaning at 12+/-2 d of age and keeping the pigs on-site in a separate but identical all-in-all-out nursery room (OSEW), or weaning at 12+/-2 d of age and moving the pigs off-site to an all-in-all-out nursery room located 16 km from the Center (SSEW). Ventilation, feed, penning, feeders, and drinkers were kept as similar as possible for all treatments. Off-site weaning improved 56-d body weight (P < .05) by 12.5 and 8.3% compared with OSEW and Control, respectively. The improvement appeared to be the result of improvements primarily in feed intake but also due to enhanced efficiency of nutrient utilization. This experiment confirms that SSEW results in significant improvements in 56-d weights, even when the herd of origin has a relatively high health status.

Aging↗
PubMed1999

Effect of segregated early weaning on postweaning small intestinal development in pigs.

The effect of segregated early weaning (SEW) on postweaning small intestinal development was investigated in SEW and control (CON) pigs. Small intestines were collected from a total of 15 pigs killed at 11 (preweaning), 15 (3 d postweaning), and 34 d of age. At 3 d postweaning, the SEW and CON pigs had shorter villi (P<.01), deeper crypts (P<.01), and reduced (P<.01) ratios of villus height:crypt depth (V:C) compared with preweaning. Weaning also reduced specific activities of lactase (P<.01) in duodenum and ileum and alkaline phosphatase (ALP) (P<.05) in duodenum and jejunum. Sucrase activity in the three regions of the small intestine marginally decreased in both groups at 3 d postweaning. The mucosal protein:DNA ratio in duodenum and jejunum increased (P<.05) in SEW and CON pigs at 3 d postweaning compared with preweaning pigs. The SEW and CON treatments resulted in differences in postweaning gut development. At 15 d of age in SEW pigs, the mucosal protein:DNA ratio in duodenum and jejunum were 20 and 25.5% (P<.05) less, respectively, than those in CON pigs. However, at 34 d, these ratios in duodenum, jejunum, and ileum were 43.5 (P<.05), 24.3, and 32.9% (P<.05) greater, respectively, in SEW pigs than in CON pigs. Longer villi, shorter crypts (P<.01), and higher V:C ratios (P<.01) in jejunum and ileum were observed in SEW pigs vs CON pigs at 34 d of age. The specific activities of lactase in duodenum (P<.01) and jejunum (P<.05) and of ALP in duodenum (P<.01) were higher in SEW pigs. Sucrase activity in duodenum, jejunum, and ileum was 21.7, 46.3 (P<.05), and 11.2% greater in SEW pigs at 34 d of age. These results demonstrate differences in postweaning gut development between SEW and CON pigs. Furthermore, the number of intraepithelial lymphocytes in jejunum was greater (P<.001) in 34-d-old SEW pigs compared with CON pigs. Microscopy revealed a thick mucus coating over epithelial cells in the ileum of 34-d-old CON pigs that was not apparent in the SEW pigs. These observations are consistent with reduced pathogen exposure associated with SEW. We suggest that segregated early weaning advances postweaning gut maturation, which is consistent with improved growth and feed efficiency observed in SEW pigs.

Animals↗
PubMed1997

The novel human HNF-3/fork head-like 5 gene: chromosomal localization and expression pattern.

Analysis of cDNA clones, isolated from a human fetal brain cDNA library, that hybridized with the rat HNF-3 alpha fork head homolog domain revealed the 3.6-kb HFKL5 cDNA. The transcript of HFKL5 is 4.4 kb long and represents a novel member of the HNF-3/fork head transcription factor family. Comparison of the amino acid sequence of the fork head domain reveals a relatively low level of homology to other members of this family of genes, the closest related sequence being rat HFH7 with 68% homology. The HFKL5 cDNA codes for a putative 500-amino-acid protein. Southern analysis revealed that the HFKL5 gene homolog is present as a single copy in the human genome. Zoo Southern analysis showed strong evolutionary conservation of HFKL5 among mammalian and possibly avian species. Expression of HFKL5 in neurons is restricted to the fully differentiated neurons in fetal and adult brain as well as in the parasympathic ganglia of the small intestine. We also observed expression in lymphocytes, kidney tubule cells, and a subset of hepatocytes. The HFKL5 gene homolog was mapped to chromosome 22q13-qter by cell panel hybridization.

Adult↗
PubMed1996

Effect of recombinant bovine interleukin-1 beta in normal calves and in calves infected with bovine herpesvirus type 1.

Bovine herpesvirus-1 (BHV-1) is an important pathogen of respiratory infections in cattle. Its continuing importance lies in its ability to predispose infected hosts to bacterial infections. In this present study, we determined whether the immunoregulatory effects induced by interleukin-1 (IL-1) could stimulate appropriate host defense mechanisms to influence the course of BHV-1 infection in cattle. We first evaluated the effect of different doses (10-1000 ng/kg) of IL-1 in normal cattle. A single administration of IL-1 was able to induce a dose-dependent increase in polymorphonuclear (PMN) cells as well as monocytes in peripheral blood. The number of CD3+ lymphocytes and gamma/delta T cells in peripheral circulation decreased transiently in a dose-dependent manner. In the disease model, the effect of IL-1 administration (300 ng/kg) 24 h before, at the time of, and 24 h after the BHV-1 challenge was assessed. As a single therapeutic modality, IL-1 did not significantly reduce the establishment or progression of BHV-1-induced disease. Nevertheless, our results demonstrated that the significant modulation of diverse immune parameters did not exacerbate disease. Thus, the use of IL-1 as an adjunct therapy or as a vaccine adjuvant in cattle can be safely considered in situations where BHV-1 infection is likely to occur.

Adjuvants, Immunologic↗
PubMed1995

Regulation of bovine acute phase responses by recombinant interleukin-1 beta.

The acute phase response is a collection of physiologic changes initiated early in the inflammatory process. This response is comprised of both localized changes at the site of infection or injury and the initiation of systemic responses, such as the increase in production of acute phase proteins. Cytokines such as interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF) play key roles in the regulation of acute phase response in the species studied to date. To better characterize the acute phase response of cattle, recombinant bovine (rBo). IL-1 beta was administered to cattle. A single administration of rBoIL-1 beta was able to induce a dose dependent increase in body temperature, circulating leukocytes, and serum haptoglobin and fibrinogen concentrations, as well as a decrease in plasma zinc concentration. Five daily administrations of rBoIL-1 beta resulted in heightened and prolonged elevations of haptoglobin and fibrinogen. In addition, alpha 1-acid glycoprotein levels were increased, a response not seen after a single administration of rBoIL-1 beta. These results indicate that IL-1 is an important regulator of the acute phase response in cattle.

Acute-Phase Reaction↗
PubMed1993

Acute or chronic immunoneutralization of somatostatin does not affect growth hormone or thyroid hormone secretion in sheep.

The effect of acute or chronic immunoneutralization of somatostatin (SRIF) on plasma GH, thyrotrophin (TSH) and thyroid hormones was examined. Acute responses to SRIF immunoneutralization were examined using 30 intact male lambs (19.8 +/- 0.6 kg) assigned to one of five treatment groups such that control (C) lambs received no anti-SRIF immunoglobulin and SRIF-immunized (SI) lambs received 2 mg (SI2), 10 mg (SI10), 20 mg (SI20) or 100 mg (SI100) anti-SRIF immunoglobulin/kg body weight (BW). Control immunoglobulin was administered such that all lambs received 100 mg total immunoglobulin protein/kg BW. Effects of chronic SRIF immunoneutralization were examined using C and SI100 lambs which received additional (40 mg/kg BW) control and anti-SRIF immunoglobulin respectively, 4 and 8 days following the initial dose. Blood samples were collected from all lambs, at 10-min intervals, for 5 h immediately following initial immunoglobulin infusion and, from C and SI100 lambs, at 10-min intervals, for 5 h at 11 days following initial immunoglobulin infusion. At the end of each 5-h sampling period, pituitary and thyroid function was examined by i.v. challenge with thyrotrophin-releasing hormone (TRH; 0.33 microgram/kg BW). Basal plasma GH and thyroxine (T4) and the GH, TSH, T4 and tri-iodothyronine (T3) responses to TRH were not influenced by acute or chronic immunoneutralization of SRIF. Acute, but not chronic, immunoneutralization of SRIF elevated basal plasma T3 in SI100 lambs only. The results suggest that SRIF, under physiological conditions, does not influence GH or thyroid hormone secretion in sheep but may influence thyroid hormone metabolism acutely.

Animals↗
PubMed1990

Effect of immunization against somatostatin in the pregnant ewe on growth and endocrine status of the neonatal lamb.

Absorption of somatostatin (SRIF) specific antibodies from colostrum of ewes actively immunized against SRIF may improve growth rate of the neonatal lamb by neutralizing the inhibitory effects of SRIF on pituitary and thyroid function. Growth and endocrine parameters in the offspring of SRIF immunized (SI) and control (C) crossbred ewes were examined. Lamb weight was recorded at birth and twice each week to 24 days of age. Blood samples were collected prior to first suckle and twice each week. At 21 to 24 days of age, in separate experiments, lambs were infused with glucose (0.29 g/kg), arginine (0.25 g/kg) or thyrotropin-releasing hormone (TRH; 0.33 microgram/kg). A strong correlation (R = 0.88; P less than .01) was observed between anti-SRIF titre in the ewe at parturition and in the lamb at 3 days of age. No effect on lamb birth weight (SI 4.28 +/- 0.27 kg; C 4.35 +/- 0.23 kg) was observed. At 24 days of age cumulative gain in SI lambs (5.4 +/- 0.32 kg) was greater (P less than .05) than in C lambs (4.5 +/- 0.32 kg). The growth hormone secretory responses to glucose or arginine were not affected by treatment. Plasma IGF-I, plasma thyroxine (T4) and the plasma thyrotropin and T4 responses to TRH were not different between treatments. Plasma triiodothyronine (T3) was higher (P less than .05) in SI (2.46 +/- .10 ng/ml) than in C (2.01 +/- .05 ng/ml) lambs, however, the plasma T3 response to TRH was lower in SI lambs. Plasma glucose (mg/dl) was higher (P less than .05) in SI (118.4 +/- 1.7) than in C (106.0 +/- 4.0) lambs. Plasma insulin was not affected by treatment. Increased plasma T3 and glucose concentrations during SRIF immunoneutralization in the neonate lamb may be important factors contributing to the growth response observed.

Animals↗
PubMed1990

The cellular retinoic-acid-binding protein is expressed in tissues associated with retinoic-acid-induced malformations.

Retinoic acid (RA) is thought to play a role in embryonic pattern formation in vertebrates. A naturally occurring gradient of endogenous RA has been demonstrated in the developing chick limb bud, while local application of RA leads to the formation of additional digits. In mammals, a well-defined spectrum of birth defects has been reported as a result of fetal exposure to excess RA. In analogy to the chick limb bud, it may be speculated that these malformations are the result of disturbance of morphogenetic RA concentration gradients. A candidate gene involved in the regulation of endogenous RA concentrations is the gene encoding cellular RA binding protein (CRABP). We have isolated a partial cDNA clone corresponding to the chicken homolog of CRABP, and performed in situ hybridization experiments on sections of embryos at various stages of development. CRABP expression was detected in the CNS, the craniofacial mesenchyme, ganglia of the peripheral nervous system, the limb bud, and the visceral arch area. Our results indicate that the spatiotemporally specified expression pattern displayed by the CRABP gene exhibits a striking correspondence to the tissues that are affected by exposure of avian or mammalian embryos to RA. We hypothesize that CRABP plays an important role in normal embryogenesis and that embryonic tissues showing high CRABP expression are susceptible to the adverse effects of excess RA.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Chromosomal abnormalities: detection and implications for cancer development.

The occurrence of chromosomal abnormalities is a common theme in carcinogenesis. A large proportion of tumours which have been characterized at the cytogenetic level carries numerical and/or structural aberrations. Numerical alterations may include acquisition or loss of specific chromosomes or dramatic changes in overall ploidy levels. Structural aberrations may include DNA amplifications or deletions, inversions and translocations. Many chromosomal alterations occur in a non-random fashion and may be subdivided in to primary and secondary, according to their timing of occurrence. Primary chromosomal abnormalities usually occur at the early stages of tumourigenesis and are often encountered as sole cytogenetic abnormalities. Secondary chromosomal abnormalities are usually associated with more advanced stages of tumour development. In recent years several chromosomal abnormalities could be correlated with specific gene alterations, thus providing insights into the molecular mechanisms underlying tumourigenesis. The biological consequences imparted by other chromosomal changes such as numerical changes are, however, less clear. By using recently developed molecular techniques for chromosome characterization, so-called molecular cytogenetics, our perception on cancer cytogenetics is rapidly changing through the disclosure of hitherto unknown (specific) chromosomal abnormalities.

Chromosome Aberrations↗