Browsing by Subject "immunity"
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Item Differential gene expression in innate immunity between commercial broilers and layers(2009-06-02) Shen, ShixueTremendous improvements have been achieved in growth rates and feed efficiency in commercial broiler birds. However, fast growth broilers generally show weak immune competence and disease resistance. Innate immunity is the first line of defense providing immediate killing effects to a broad range of infectious pathogens and limiting infections to a minimum at an early stage before the activation of more specific adaptive immunity. Acute phase proteins (APPs), defensins and Toll-like receptors (TLRs) are all important innate immune molecules functioning from recognition to killing the foreign microbes. Tibial dyschondroplasia (TD) is one chicken disease associated with rapid growth in broilers. The objective of this research was to study the differential expression of innate immune related genes in liver and spleen tissues between commercial broilers and layers with the stimulation of lipopolysaccharide (LPS). Also, this study investigated mechanisms involved in the pathogenesis of TD at molecular levels. This study first identified and annotated nineteen new chicken APPs genes from the chicken genome draft with bioinformatics tools. Using a relative quantitative real-time RT-PCR method, the expression levels of all thirty-one APPs, thirteen defensins and eight TLRs genes were systemically investigated at the transcriptional level at three time points (0-, 3-, 8-hour) with the challenge of LPS. This study showed that broiler birds generally expressed significantly lower levels of all three families of innate immune related genes than layers and the inductive extent of these genes are generally smaller in broilers too. Close investigation of some important signaling transcription factors (NF-kB and IRF-3) and cytokine (IL-6) also reached the same conclusion. This study revealed that the inadequate expression of deiodinase type 2 (DIO2) contributed to the pathogenesis of TD in rapid growth broilers. All of the experimental results solidly validate the hypothesis that a compromised innate immune response or weak disease resistence is associated with fast growth broiler birds.Item The influence of lipid rafts on aging and immunology(2009-08) Feng, Haoqi; Jolly, Christopher A.; Ciolino, HenryLipid rafts are operationally defined as cholesterol-rich membrane microdomains resistant to solubilization in nonionic detergents at low temperatures. Lipid rafts, which are quite different in lipid composition from the surrounding membranes, are of great importance to signal transduction, protein sorting and membrane transport. They have been implicated in a range of biosynthetic and endocytic processes and systems-signaling, molecular trafficking, diseases as well as being involved in the immune, vascular, digestive and reproductive systems. Dietary nutrients like fatty acids and vitamins of different types also play a critical and decisive role in the regulation of lipid rafts.Item Nutritional modulation of immunity and physiological responses in beef calves(Texas A&M University, 2004-11-15) Kurz, Michael WayneTwenty-four crossbred steer calves (235 + 6 kg initial BW) were weaned, adapted to a growing diet, trained to use Calan feeders and assigned to one of four treatments in a 2 x 2 factorial arrangement as follows: (1) no transit stress and saline injection, (2) no transit stress and trace mineral and vitamin E (TM/VitE) injections, (3) transit stress and saline injection and (4) transit stress and TM/VitE injection. TM/VitE injections consisted of MultiminTM to provide 0.3, 0.6, 0.15 and 0.6 mg of Cu, Mn, Se, and Zn/kg BW, respectively, and Vita ETM to provide 9 IU of VitE/kg BW on d 0 and 21 of the study. On d 24, transit-stressed steers were subjected to a three-d, 2000-km, transportation period. During the 56-d experiment, liver and serum samples were assayed to assess trace mineral status, antibody titers to keyhole limpet hemocyanin (KLH) measured to assess humoral immunity and phytohemagglutinin(PHA)- and ovalbumin(OVA)-induced skin swelling and lymphocyte proliferation measured to assess cellular immunity. TM/VitE-injected steers grew slower (P < 0.05) over the first 24 d of the experiment and tended (P = 0.10) to grow slower after transit. TM/VitE injections increased (P < 0.05) liver Cu and Zn concentrations 135 and 21 % by d 30, respectively. TM/VitE-injected steers had increased (P < 0.05) serum Cu on d 24 and 26, but decreased (P < 0.05) serum Zn and whole blood Se compared to saline-injected steers on d 24 and 56. TM/VitE injections increased serum α-tocopherol concentrations. TM/VitE injections did not affect humoral immunity, but decreased (P < 0.05) skin-swelling responses to PHA on d 21, and decreased (P < 0.05) lymphocyte proliferation to OVA and KLH. Transit-stressed steers had higher (P < 0.05) serum Cu on d 26, and higher (P < 0.05) liver Cu concentrations on d 56 than non-transit-stressed steers. Transit stress did not affect serum Zn or whole blood Se concentrations. Injections of TM/VitE increased Cu, Zn and vitamin E, but not Se status. The TM/VitE treatment suppressed growth and cellular immune function suggesting that levels of trace minerals used in this study were too high.