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ABSTRACT: Direct fed microbials and probiotics are used to promote health in livestock and poultry; however, their mechanism of action is still poorly understood. We previously reported that direct fed microbial supplementation in young broilers reduced ileal respiration without changing whole-body energy expenditure. The current studies were conducted to further investigate the effects of a direct fed microbial on energy metabolism in different tissues of broilers. One hundred ninety-two 1-d-old broiler chicks (16 chicks/pen) were randomly assigned to 2 dietary groups: standard control starter diet (CSD) and CSD plus direct fed microbial (DFMD; 0.3%) with 6 pens/treatment. Body weight, feed consumption, whole-body energy expenditure, organ mass, tissue respiration rates, and peripheral blood mononuclear cell (PBMC) ATP concentrations were measured to estimate changes in energy metabolism. No differences in whole body energy expenditure or BW gain were observed; however, decreased ileal O(2) respiration (P < 0.05) was measured in DFMD fed broilers. In contrast, the respiration rate of the thymus in those broilers was increased (P < 0.05). The PBMC from DFMD fed broilers had increased ATP concentrations and exhibited increased ATP turnover (P < 0.01). To determine if the increased energy consumption by PBMC corresponded with an altered immune response, broilers were immunized with sheep red blood cells (SRBC) and assayed for differences in their humoral response. The DFMD-fed broilers had a faster rate of antigen specific IgG production (P < 0.05) and an increase in total IgA (P < 0.05). Collectively, these data indicate that supplementation with the direct fed microbial used in this study resulted in energy re-partitioning to the immune system and an increase in antibody production independent of changes in whole body metabolism or growth performance.
Journal of Animal Science 02/2012; 90(8):2639-51. · 2.10 Impact Factor
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ABSTRACT: 1. Four experiments were conducted to evaluate the effects of temperature (TEM) and oxygen (O(2)) concentrations during the last 4 d of incubation on bone development. Fertile eggs from two strains were obtained that either exhibited Low or High eggshell conductance (G). 2. Four experimental cabinets provided either four TEM (36, 37, 38 or 39 degrees C) or four O(2) concentrations (17, 19, 21 or 23% O(2)). Data were analysed as a 2 x 2 factorial design. In the fourth experiment, two temperatures (36 and 39 degrees C), two O(2) concentrations (17 and 23%) and the same Low and High G strains were evaluated in a 2 x 2 x 2 factorial design. 3. Body weights (BW) and residual yolks were obtained, both legs were dissected. Femur, tibia and shank weights, length and thickness were recorded. Relative asymmetry (RA) of each leg section was calculated. 4. The results indicated that elevated TEM during incubation increased RA between the two legs, mainly in the Low G strain. Chickens at the lowest O(2) concentrations had lighter and shorter tibias, lighter shanks, and increased RA of femur length compared to chickens in the 23% O(2). In the fourth experiment no interactions were observed between O(2) and TEM. High TEM depressed BW of Low G broilers, but no significant effect of treatments was observed on BW of High G broilers. Nevertheless, the high TEM or low O(2) independently caused reduced femur and tibia weights and length, shank length and thickness, and both low O(2) and high TEM together increased RA in shank weight. 5. These results suggest that late incubation conditions affect long bone development in broilers.
British Poultry Science 12/2008; 49(6):666-76. · 1.00 Impact Factor
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British Poultry Science 11/2008; 49(6):666-676. · 1.00 Impact Factor
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ABSTRACT: The current study investigated whole-body O2 consumption, intestinal O2 consumption, and intestinal inflammation status through mucosal cytokine production on broiler chicks fed the direct-fed microbial PrimaLac. One hundred twenty 1-d-old broiler chicks were randomly assigned to 1 of 3 experimental diets: standard starter diet (control), standard starter diet with added salinomycin (SAL), and standard starter diet with added PrimaLac (DFM). Birds were housed in 2 separate rooms, the control and SAL treatments in one room and the DFM in another. Intact ileal and cecal samples were collected on d 19, 20, and 21 after measuring whole-body O2 consumption using indirect calorimetry. The O2 up-take of ileal tissue was measured using an in vitro O2 monitor. Analysis of intestinal immune status of broilers was measured by the relative differences in mRNA of both pro- and antiinflammatory cytokines: interleukin-(IL) 1beta, IL-6, and IL-10 using real-time reverse transcription-PCR. Broilers exhibited a 6 to 16% decrease in whole-body energy expenditures and up to a 47% decrease (P<0.05) in ileal energy expenditures in the DFM group compared with other treatments. The reverse transcription-PCR data demonstrated that DFM consortium numerically altered both pro- and antiinflammatory cytokines within the ileum of 19-d posthatch broilers. These data suggest that direct-fed microbials like PrimaLac increase metabolic efficiency via changes in intestinal physiology and metabolism.
Poultry Science 06/2007; 86(6):1100-6. · 1.73 Impact Factor
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ABSTRACT: Direct-fed microbials (DFM) could serve as a potential alternative to the feeding of antibiotics in poultry production. In this study, the effects of providing a DFM were compared with the feeding of salinomycin on intestinal histomorphometrics, and microarchitecture was examined. Broiler chicks (n=18 per treatment; trials 1 and 2) were fed a standard starter diet (control), control+PrimaLac (DFM; 0.3% wt/wt), and control+salinomycin (SAL; 50 ppm) from hatch to 21d. The birds were euthanized on d 21, and the ileal, jejunal, cecal, and colon tissues were dissected. Samples were examined by light microscopy (jejunum and ileum; trial 1) and scanning electron microscopy (ileum, cecum, and colon; trial 2). Feeding of the DFM increased intestinal muscle thickness (P<0.05) up to 33% compared with the control treatment. The DFM group also had increased villus height and perimeter (P=0.009 and 0.003, respectively) in jejunum. Segmented filamentous-like bacteria were less numerous in DFM-treated chicks than in the control chicks. Very few segmented filamentous-like bacteria were found near other microbes in the ileum. The DFM chicks had a larger number of bacteria positioned over or near goblet cells and in intervilli spaces. Bacteria in the colon were observed to be attached primarily around and within the crypts. Mucous thickness was less, and the density of bacteria embedded in the mucous blanket appeared to be lower in DFM-treated animals than in the control in all intestinal segments. The birds fed SAL had fewer bacteria and enterocytes in the ileum than in the control-and DFM-treated birds, and they had thicker and fewer microvilli. Because gastrointestinal track colonization by the DFM organisms can prevent the attachment of pathogens to the epithelium, spatial relationships, in this study, demonstrate the functionality of DFM and probiotics in preventing disease. It also supports previous observations that the feeding of salinomycin may alter intestinal function.
Poultry Science 06/2007; 86(6):1121-32. · 1.73 Impact Factor
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ABSTRACT: The poultry industry is facing a ban on the use of antibiotic feed additives in many parts of the world. Consequently, there is a growing interest in finding viable alternatives for disease prevention and growth enhancing supplements. The effects of probiotics or direct fed microbials (DFM) on gut health and performance in poultry as well as other species are presented. The interactions between intestinal microbiota, the gut epithelium and the immune system are important in the competitive exclusion process. The mechanisms by which probiotics operate include spatial exclusion, micro-environmental alterations, production of antimicrobial substances and epithelial barrier integrity. The preponderance of research data in this field suggests the likelihood of a small but additive series of beneficial changes from an animal`s exposure to probiotics. Further investigations will be needed to fully characterize the effects and sustained outcomes of probiotic and DFM treatments in poultry.
International Journal of Poultry Science. 01/2007;
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ABSTRACT: Astroviruses are small round viruses that cause enteric disease in the young of several species. Detection and diagnosis of astrovirus infection in non-human hosts relies heavily on electron microscopy and fluorescent antibody tests. Recently, our laboratory isolated and sequenced an avian astrovirus from poult enteritis mortality syndrome affected turkeys. These studies describe the development of RT-PCR methods, which specifically detect regions of the viral capsid and polymerase genes, and demonstrate their use in detecting astrovirus infection in commercial turkey flocks.
Journal of Virological Methods 11/2000; 90(1):79-83. · 2.01 Impact Factor
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ABSTRACT: Astroviruses are known to cause enteric disease in several animal species, including turkeys. However, only human astroviruses have been well characterized at the nucleotide level. Herein we report the nucleotide sequence, genomic organization, and predicted amino acid sequence of a turkey astrovirus isolated from poults with an emerging enteric disease.
Journal of Virology 08/2000; 74(13):6173-7. · 5.40 Impact Factor
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ABSTRACT: To understand astrovirus biology, it is essential to understand factors associated with its evolution. The current study reports the genomic sequences of nine novel turkey astrovirus (TAstV) type 2-like clinical isolates. This represents, to our knowledge, the largest genomic-length data set available for any one astrovirus type. The comparison of these TAstV sequences suggests that the TAstV species contains multiple subtypes and that recombination events have occurred across the astrovirus genome. In addition, the analysis of the capsid gene demonstrated evidence for both site-specific positive selection and purifying selection.
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ABSTRACT: Outbreaks of poult enteritis mortality syndrome (PEMS) continue to cause financial losses to the turkey industry. Clinically, PEMS is defined by mortality profiles, diarrhea, flock unevenness, and immunosuppression. PEMS is a very difficult disease to control and prevent. Depopulation of PEMS-affected flocks and thorough cleaning of the contaminated housing have failed to prevent infection (disease) in subsequent flock placements. The relationship of PEMS to other enteric disease complexes of young turkeys is unknown, partly because the causative agent of PEMS remains unknown. Recently, we isolated a unique astrovirus strain from the thymus and intestines of PEMS-infected poults. This strain is molecularly and serologically distinct from the astrovirus that circulated in turkeys in the 1980s. Mammalian astroviruses are very resistant to inactivation. In these studies, we examined the stability of partially purified PEMS-associated astrovirus to inactivation with heat, laboratory disinfectants, and commercial disinfectants used in commercial turkey houses in an embryonated egg model system. Similar to mammalian astroviruses, the PEMS-associated astrovirus is resistant to inactivation by heat, acidification, detergent treatment, and treatment with phenolic, quaternary ammonium, or benzalkonium chloride-based products. Only treatment with formaldehyde, beta-propriolactone, or the peroxymonosulfate-based product Virkon S completely inactivated the astrovirus in the embryo model. These studies provide an alternate means to potentially control at least one virus associated with PEMS through the use of specific disinfectants.
Avian Diseases 45(1):76-82. · 1.46 Impact Factor
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ABSTRACT: Poult enteritis mortality syndrome (PEMS), a highly infectious disease of young turkeys, causes serious financial losses to the turkey industry. Clinically, PEMS is defined by mortality profiles, diarrhea, growth depression, and immunosuppression. Although many viruses, bacteria, and parasites are found in PEMS-infected birds, the inciting agent remains unknown. Experimentally, PEMS can be reproduced by exposing naïve poults to the intestinal contents from infected birds. Previous reports suggest that extraintestinal tissues fail to reproduce the disease. Histopathologic examination of tissues from PEMS-infected poults suggested that the thymus exhibited the earliest signs of pathology. On the basis of these observations, we hypothesized that the thymus harbors an agent(s) involved in PEMS. In these studies, naïve turkey poults were orally inoculated with a bacteria-free filtrate composed of either the intestines and feces or the thymus from PEMS-infected birds and were monitored for clinical signs of PEMS. Poults exposed to a filtrate composed solely of the thymus from PEMS-infected birds exhibited diarrhea, growth depression, mortality, pathology, and, most importantly, immunosuppression similar to poults exposed to the intestinal filtrate. The results of this study suggest that the thymus of infected birds harbors the agent(s) that can reproduce a PEMS-like disease in turkey poults.
Avian Diseases 44(2):256-65. · 1.46 Impact Factor
