The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Peter S Holt - One of the best experts on this subject based on the ideXlab platform.
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the effect of killed salmonella enteritidis vaccine prior to Induced Molting on the shedding of s enteritidis in laying hens
Avian Diseases, 2004Co-Authors: Masayuki Nakamura, Tomoshi Nagata, Shizuka Okamura, Kazuaki Takehara, Peter S HoltAbstract:Abstract Effects of administering killed Salmonella enterica serovar enteritidis (SE) vaccines to laying hens prior to Induced Molting on egg production and on shedding of SE were investigated. Forty hens were vaccinated with one of two SE vaccines available commercially in the United States and Japan. Twenty-five days after vaccination, feed was withdrawn for 2 wk from 20 vaccinated plus 10 unvaccinated hens to induce molt. Four days after molt induction, all hens were challenged with a dose of 2.4 × 109 of SE. For the 25 days following administration of the SE bacterins, egg production in vaccinated hens showed approximately a 15% decrease. After molt induction, egg production in molted hens ceased and then returned to normal levels 8 or 9 wk postvaccination. Through the 3-mo experimental period, the decreases in numbers of eggs laid in the unvaccinated/molted group and two vaccinated/molted groups were 225 (26.2%), 245 (28.4%), and 274 (31.9%), respectively, compared with 860 in the unvaccinated/unmolt...
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Molting and Salmonella enterica serovar enteritidis infection: the problem and some solutions
Poultry Science, 2003Co-Authors: Peter S HoltAbstract:Abstract Induced Molting is an important economic tool used by the egg industry to recycle an aging layer flock. It is estimated that approximately 70% of the flocks nationwide and almost 100% in California are molted annually. Considering that there are approximately 240 million hens in production in the U.S., a rough estimate of the numbers of hens molted every year would be between 144 and 168 million birds, a substantial number. There are many methods to induce molt, but feed removal until hens lose a specific weight is the most prevalent molt strategy in the U.S. However, experimental studies in our laboratory have shown that Induced Molting via feed removal depresses the immune system of hens and exacerbates a Salmonella enteritidis (SE) problem in a simulated flock situation. Molted hens excreted significantly higher SE numbers in the feces, had higher numbers of SE in internal organs, and exhibited more intestinal inflammation. Molted hens were 100- to 1,000-fold more susceptible to infection by SE and therefore more readily transmitted the organism to uninfected hens in neighboring cages. With the problems identified, solutions were sought, and several were successful in ameliorating the SE issue. Antibiotic therapy, vaccination, and use of low-energy, low-calcium diets to molt hens all dramatically decreased SE shedding during molt. All of the solutions provide the producer with many potential solutions to the SE food safety issue and still allow them to recycle their hens.
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Comparison of the effects of infection with Salmonella enteritidis, in combination with an Induced molt, on serum levels of the acute phase protein, alpha1 acid glycoprotein, in hens.
Poultry Science, 2002Co-Authors: Peter S Holt, Richard K. GastAbstract:Abstract Periods of inflammation due to infection, injury, or malignancy are marked by increases in serum constituents known as acute phase proteins (APP), and these proteins have been used as markers for early stages of disease. Four experiments were performed to examine whether levels in chickens of one such APP, alpha1 acid glycoprotein (AGP), would be affected by an infection with Salmonella enteritidis (SE) and if the added stress of Induced Molting via 14-d feed withdrawal would increase these effects. In all experiments but Experiment 1, hens were divided into four equal groups: molted infected, nonmolted infected, molted noninfected, nonmolted non-infected (Experiment 1 lacked this last group). Blood and intestinal samples were collected at various times from the hens and assayed for AGP and SE levels, respectively. Infection with SE significantly elevated serum AGP levels above those found in the noninfected groups of hens in two of four experiments, whereas in molted infected hens, serum AGP levels were significantly higher than those found in the noninfected counterparts in all four experiments. Comparison of AGP titer between the infected groups of hens revealed that significantly higher SE levels generally did not guarantee significantly higher AGP levels, although when individual values were plotted, a trend was observed toward increasing serum levels concomitant with increasing SE counts. Serum AGP levels show promise as a method to detect infection problems in hens, especially when the severity of the infection is exacerbated by stress situations. However, more work is needed to determine what other factors may elevate serum AGP levels and potentially confound the picture.
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the effects of Induced Molting on the severity of acute intestinal inflammation caused by salmonella enteritidis
Avian Diseases, 1997Co-Authors: N P Macri, Robert E Porter, Peter S HoltAbstract:SUMMARY. This study describes and compares early inflammation caused by Salmonella enteritidis in molted and nonmolted hens. Adult white leghorn chickens were orally infected with Salmonella enteritidis 4 days after feed removal. At 2, 4, 8, 10, 24, 48, 72, and 96 hr after infection, the hens were euthanatized, and the duodenum, jejunum, ileum, cecum, and colon were evaluated by light microscopy. Two trials were conducted, and in both trials inflammation occurred more frequently and was significantly greater in the cecum and colon of molted-infected hens compared with nonmolted-infected hens beginning at 8 hr after infection. In one trial, inflammation was more severe in the ileum of molted-infected hens compared with nonmolted-infected hens. Results indicated that Molting by feed deprivation shortened the time of onset and increased the severity of acute intestinal inflammation caused by Salmonella enteritidis.
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effect of Induced Molting on the recurrence of a previous salmonella enteritidis infection
Poultry Science, 1993Co-Authors: Peter S Holt, E Robert J R PorterAbstract:Abstract Previous work in the authors’ laboratory had shown that hens infected with Salmonella enteritidis (SE) during the feed removal phase of Induced molt shed significantly more SE and more readily transmitted SE to uninfected hens in adjacent cages when compared with unmolted hens. A study was conducted to examine the effect of Induced Molting on the recurrence and horizontal transmission of a previous SE infection. Hens aged 59 and 69 wk in Trials 1 and 2, respectively, were infected with SE and then molted 21 days later. In Trial 1, more molted hens were SE-culture-positive on Days 38 (P ≤ .005) and 45 (P ≤ .005) postinfection, and these hens shed more SE on these days (P ≤ .05 and P ≤ .005, respectively) than unmolted hens. Horizontal transmission of SE to previously uninfected but contact-exposed hens in adjacent cages was also higher in the molted group than the unmolted group on Days 38 (P ≤ .05) and 45 (P ≤ .001). Molted, contact-exposed hens also shed significantly more SE than unmolted hens. In Trial 2, the molted infected hens shed progressively more SE than the unmolted hens but the differences were not significant. However, more molted contact-exposed hens became SE-positive at Day 31 (P ≤ .05) and 38 (P ≤ .005) and also shed more SE on these days (P ≤ .05 and P ≤ .01, respectively) than the unmolted hens. Serum and intestinal antibody titers to SE were also examined in Trial 2. Molting appeared to exert no effect on the serum SE titers, but antibody titers in the alimentary tract were lower in the molted hens than the unmolted hens on Days 45 (P ≤ .005) and 52 (P ≤ .05). In Trial 1, three of eight molted directly infected hens and two of eight molted contact-exposed hens produced an SE-contaminated egg, but none of the unmolted hens produced any SE-contaminated eggs. In Trial 2, no SE-contaminated eggs were produced.
Wayne Schlosser - One of the best experts on this subject based on the ideXlab platform.
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review of Induced Molting by feed removal and contamination of eggs with salmonella enterica serovar enteritidis
Veterinary Microbiology, 2008Co-Authors: Neal J Golden, Harry H Marks, Margaret E Coleman, Carl M Schroeder, Nathan Bauer, Wayne SchlosserAbstract:Abstract As laying hens age, egg production and quality decreases. Egg producers can impose an Induced molt on older hens that results in increased egg productivity and decreased hen mortality compared with non-molted hens of the same age. This review discusses the effect of Induced Molting by feed removal on immune parameters, Salmonella enterica serovar Enteritidis (SE) invasion and subsequent production of SE-contaminated eggs. Experimental oral infections with SE show molted hens are more susceptible to SE infection and produce more SE-contaminated eggs in the first few weeks post-molt compared with pre-molt egg production. In addition, it appears that molted hens are more likely to disseminate SE into their environment. Molted hens are more susceptible to SE infection by contact exposure to experimentally infected hens; thus, transmission of SE among molted hens could be more rapid than non-molted birds. Histological examination of the gastrointestinal tracts of molted SE-infected hens revealed more frequent and severe intestinal mucosal lesions compared with non-molted SE-infected hens. These data suggest that Induced Molting by feed deprivation alters the normal asymptomatic host–pathogen relationship. Published data suggest the highest proportion of SE-positive eggs is produced within 1–5 weeks post-molt and decreases sharply by 6–10 weeks and dissipates to the background level for non-molted hens by 11–20 weeks. Appropriate treatment measures of eggs produced in the fist 5 weeks post-Molting may decrease the risk of foodborne infections to humans.
N. R. Sundaresan - One of the best experts on this subject based on the ideXlab platform.
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High doses of dietary zinc induce cytokines, chemokines, and apoptosis in reproductive tissues during regression
Cell and Tissue Research, 2008Co-Authors: N. R. Sundaresan, D. Anish, K.v.h. Sastry, V. K. Saxena, J Mohan, K. Nagarajan, J. Subramani, N. Shit, M. Saxena, K. A. AhmedAbstract:In chickens, high levels of dietary zinc cause Molting, and the reproductive system undergoes complete remodeling concomitant to feather replacement. In the present study, the expression profiles of cytokines and chemokines were investigated in the ovary and oviduct of control hens and of hens Induced to molt by zinc feeding. The zinc-Induced feed-intake suppression, the changes in corticosterone levels, the immune cell populations in the reproductive tract, and the apoptosis of reproductive tissues were analyzed. The expression of mRNAs for interleukin-6 (IL-6), interferon-γ (IFN-γ), the avian ortholog of mammalian IL-8 (chCXCLi2), and a chicken MIP-1β-like chemokine (chCCLi2) in the ovary and of mRNAs for IL-1β, IL-6, IFN-γ, transforming growth factor-β2, chCXCLi2, and chCCLi2 in the oviduct were upregulated significantly during zinc-Induced Molting. A simultaneous feed-intake reduction was observed with higher expression of cytokines and chemokines. The results of the present investigation also suggested that the upregulation of corticosterone was closely associated with the increased expression of cytokines and chemokines. An increase in apoptosis within reproductive tissue during tissue regression was also noted. We had previously observed the upregulation of these cytokines expression in an earlier study (Molting by feed withdrawal). However, the pattern and the level of expression were different among these two methods. These findings indicate that cytokines might be a common mediator of tissue regression during Molting Induced by diverse methods, although the pattern of induction is different. Thus, a high dose of dietary zinc seems to induce reproductive regression via the upregulation of cytokines and chemokines, the suppression of feed intake, and the increase in serum corticosterone, resulting finally in the apoptosis of reproductive tissues.
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differential expression of lipopolysaccharide Induced tnf α factor litaf in reproductive tissues during Induced Molting of white leghorn hens
Animal Reproduction Science, 2007Co-Authors: N. R. Sundaresan, D. Anish, K.v.h. Sastry, V. K. Saxena, J Mohan, M K SaxenaAbstract:Abstract The reproductive remodeling during Molting appears to be a complex physiological mechanism regulated by multiple host factors. Lipopolysaccharide (LPS) Induced TNF-α factor (LITAF) is one of the transcription factors controlling the expression of TNF-α and other cytokines. In the present investigation, we studied the involvement of LITAF in the regression of reproductive tissues of Molting birds. Semi-quantitative RT-PCR analysis revealed that LITAF mRNA was generally expressed in both ovary and oviduct. In the Molting birds, i.e. those subjected to feed withdrawal (FW) or fed high levels of zinc (ZnF) birds, the LITAF expression was upregulated significantly in the ovary after 4 days of Molting (DOM). However, LITAF mRNA levels were three-fold higher in ZnF birds, which might be responsible for a greater degree of follicular atresia. In the oviduct of FW birds, peak LITAF expression was noticed on 4DOM and the levels remained significantly higher until the end of the experiment. In ZnF birds, LITAF expression reached its peak on 1DOM and subsequently downregulated to basal levels on 2DOM. This indicated that constantly higher LITAF expression might be required for complete regression of the oviduct during Molting. In conclusion, LITAF might be one of the major transcription factors controlling reproductive regression in chicken, as the expression levels were associated with the regression pattern.
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Cytokines in reproductive remodeling of Molting White Leghorn hens.
Journal of Reproductive Immunology, 2006Co-Authors: N. R. Sundaresan, D. Anish, K.v.h. Sastry, V. K. Saxena, Jag Mohan, Khawaja Ashfaque AhmedAbstract:Abstract The role of cytokines in regression of the ovary and oviduct during Induced Molting in chickens was investigated by evaluating the expressions of IL-1β, IL-6, IFN-γ, IL-2, TGF-β2, MIP-1β and IL-8 in the regressing ovary and oviduct by semi-quantitative RT-PCR. In addition, serum hormonal profiles (estrogen, progesterone and corticosterone), along with the gross regression and histological changes of the ovary and oviduct, were investigated. The correlation between expression of cytokines and hormonal changes during the Induced Molting was also studied. The expression of IL-6, IL-8, MIP-1β and IFN-γ mRNAs in the ovary, and IL-1β, IL-6, IL-8, MIP-1β, IFN-γ and TGF-β2 mRNAs in the oviduct, were up-regulated significantly during Induced Molting, suggesting their role in tissue regression. However, histological findings suggested no significant increase in immune cells in the regressing oviduct and ovary. Significant up-regulation of TGF-β2 in the regressing oviduct might have suppressed leukocyte recruitment thereby preventing the inflammatory response and tissue damage. The down-regulation of estrogen and progesterone and up-regulation of corticosterone is well correlated with increased expression of cytokines. It appears that cytokines released during the process of Induced Molting may have a role in decreasing ovarian steroids and increasing the corticosterone levels in chicken. From this study, it may be concluded that cytokines play a major role in regression of the ovary and oviduct during Induced Molting in chickens.
Neal J Golden - One of the best experts on this subject based on the ideXlab platform.
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review of Induced Molting by feed removal and contamination of eggs with salmonella enterica serovar enteritidis
Veterinary Microbiology, 2008Co-Authors: Neal J Golden, Harry H Marks, Margaret E Coleman, Carl M Schroeder, Nathan Bauer, Wayne SchlosserAbstract:Abstract As laying hens age, egg production and quality decreases. Egg producers can impose an Induced molt on older hens that results in increased egg productivity and decreased hen mortality compared with non-molted hens of the same age. This review discusses the effect of Induced Molting by feed removal on immune parameters, Salmonella enterica serovar Enteritidis (SE) invasion and subsequent production of SE-contaminated eggs. Experimental oral infections with SE show molted hens are more susceptible to SE infection and produce more SE-contaminated eggs in the first few weeks post-molt compared with pre-molt egg production. In addition, it appears that molted hens are more likely to disseminate SE into their environment. Molted hens are more susceptible to SE infection by contact exposure to experimentally infected hens; thus, transmission of SE among molted hens could be more rapid than non-molted birds. Histological examination of the gastrointestinal tracts of molted SE-infected hens revealed more frequent and severe intestinal mucosal lesions compared with non-molted SE-infected hens. These data suggest that Induced Molting by feed deprivation alters the normal asymptomatic host–pathogen relationship. Published data suggest the highest proportion of SE-positive eggs is produced within 1–5 weeks post-molt and decreases sharply by 6–10 weeks and dissipates to the background level for non-molted hens by 11–20 weeks. Appropriate treatment measures of eggs produced in the fist 5 weeks post-Molting may decrease the risk of foodborne infections to humans.
D. Anish - One of the best experts on this subject based on the ideXlab platform.
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High doses of dietary zinc induce cytokines, chemokines, and apoptosis in reproductive tissues during regression
Cell and Tissue Research, 2008Co-Authors: N. R. Sundaresan, D. Anish, K.v.h. Sastry, V. K. Saxena, J Mohan, K. Nagarajan, J. Subramani, N. Shit, M. Saxena, K. A. AhmedAbstract:In chickens, high levels of dietary zinc cause Molting, and the reproductive system undergoes complete remodeling concomitant to feather replacement. In the present study, the expression profiles of cytokines and chemokines were investigated in the ovary and oviduct of control hens and of hens Induced to molt by zinc feeding. The zinc-Induced feed-intake suppression, the changes in corticosterone levels, the immune cell populations in the reproductive tract, and the apoptosis of reproductive tissues were analyzed. The expression of mRNAs for interleukin-6 (IL-6), interferon-γ (IFN-γ), the avian ortholog of mammalian IL-8 (chCXCLi2), and a chicken MIP-1β-like chemokine (chCCLi2) in the ovary and of mRNAs for IL-1β, IL-6, IFN-γ, transforming growth factor-β2, chCXCLi2, and chCCLi2 in the oviduct were upregulated significantly during zinc-Induced Molting. A simultaneous feed-intake reduction was observed with higher expression of cytokines and chemokines. The results of the present investigation also suggested that the upregulation of corticosterone was closely associated with the increased expression of cytokines and chemokines. An increase in apoptosis within reproductive tissue during tissue regression was also noted. We had previously observed the upregulation of these cytokines expression in an earlier study (Molting by feed withdrawal). However, the pattern and the level of expression were different among these two methods. These findings indicate that cytokines might be a common mediator of tissue regression during Molting Induced by diverse methods, although the pattern of induction is different. Thus, a high dose of dietary zinc seems to induce reproductive regression via the upregulation of cytokines and chemokines, the suppression of feed intake, and the increase in serum corticosterone, resulting finally in the apoptosis of reproductive tissues.
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differential expression of lipopolysaccharide Induced tnf α factor litaf in reproductive tissues during Induced Molting of white leghorn hens
Animal Reproduction Science, 2007Co-Authors: N. R. Sundaresan, D. Anish, K.v.h. Sastry, V. K. Saxena, J Mohan, M K SaxenaAbstract:Abstract The reproductive remodeling during Molting appears to be a complex physiological mechanism regulated by multiple host factors. Lipopolysaccharide (LPS) Induced TNF-α factor (LITAF) is one of the transcription factors controlling the expression of TNF-α and other cytokines. In the present investigation, we studied the involvement of LITAF in the regression of reproductive tissues of Molting birds. Semi-quantitative RT-PCR analysis revealed that LITAF mRNA was generally expressed in both ovary and oviduct. In the Molting birds, i.e. those subjected to feed withdrawal (FW) or fed high levels of zinc (ZnF) birds, the LITAF expression was upregulated significantly in the ovary after 4 days of Molting (DOM). However, LITAF mRNA levels were three-fold higher in ZnF birds, which might be responsible for a greater degree of follicular atresia. In the oviduct of FW birds, peak LITAF expression was noticed on 4DOM and the levels remained significantly higher until the end of the experiment. In ZnF birds, LITAF expression reached its peak on 1DOM and subsequently downregulated to basal levels on 2DOM. This indicated that constantly higher LITAF expression might be required for complete regression of the oviduct during Molting. In conclusion, LITAF might be one of the major transcription factors controlling reproductive regression in chicken, as the expression levels were associated with the regression pattern.
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Cytokines in reproductive remodeling of Molting White Leghorn hens.
Journal of Reproductive Immunology, 2006Co-Authors: N. R. Sundaresan, D. Anish, K.v.h. Sastry, V. K. Saxena, Jag Mohan, Khawaja Ashfaque AhmedAbstract:Abstract The role of cytokines in regression of the ovary and oviduct during Induced Molting in chickens was investigated by evaluating the expressions of IL-1β, IL-6, IFN-γ, IL-2, TGF-β2, MIP-1β and IL-8 in the regressing ovary and oviduct by semi-quantitative RT-PCR. In addition, serum hormonal profiles (estrogen, progesterone and corticosterone), along with the gross regression and histological changes of the ovary and oviduct, were investigated. The correlation between expression of cytokines and hormonal changes during the Induced Molting was also studied. The expression of IL-6, IL-8, MIP-1β and IFN-γ mRNAs in the ovary, and IL-1β, IL-6, IL-8, MIP-1β, IFN-γ and TGF-β2 mRNAs in the oviduct, were up-regulated significantly during Induced Molting, suggesting their role in tissue regression. However, histological findings suggested no significant increase in immune cells in the regressing oviduct and ovary. Significant up-regulation of TGF-β2 in the regressing oviduct might have suppressed leukocyte recruitment thereby preventing the inflammatory response and tissue damage. The down-regulation of estrogen and progesterone and up-regulation of corticosterone is well correlated with increased expression of cytokines. It appears that cytokines released during the process of Induced Molting may have a role in decreasing ovarian steroids and increasing the corticosterone levels in chicken. From this study, it may be concluded that cytokines play a major role in regression of the ovary and oviduct during Induced Molting in chickens.