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Host Defense and Parasite Evasion
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Some intracellular parasites also interfere with apoptosis, ordinarily a key defense against such parasites. By preventing apoptosis, parasites extend the life of their host cell until their replication within the cell is complete. Eimeria tenella, to cite one example, invades epithelial cells in the intestinal ceca of chickens. This serious pathogen can cause high mortality, especially in young birds. Early in an infection, the parasite causes activation of a host cell transcription factor, resulting in the increased expression of proteins that block an apoptotic response. Likewise, T. gondii employs several mechanisms to ensure that infected cells do not undergo apoptosis. The cell death that is characteristic of apoptosis is often preceded by the release of cytochrome C from mitochondria. This cytochrome, in turn, initiates caspase activation. Once it is activated, caspase, in turn, activates caspase-activated DNAase (CAD), which degrades the cell’s DNA effectively killing it. But in T. gondii-infected cells, the parasite stimulates the up-regulation of Bcl-2 and Heat Shock Protein 70, two host proteins which reduce cytochrome C release, thereby preventing caspase activation and subsequent apoptosis.
Essential Oils Used in Veterinary Medicine
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
K. Can Başer Hüsnü, Chlodwig Franz
Antioxidant activities of rosemary and sage oils on lipid oxidation of broiler meat have been shown. Following dietary administration of rosemary and sage oils to the live birds, a significant inhibition of lipid peroxidation was reported in chicken meat stored for 9 days (Lopez-Bote et al., 1998). A dietary supplementation of oregano essential oil (300 mg/kg) showed a positive effect on the performance of broiler chickens experimentally infected with Eimeria tenella. Throughout the experimental period of 42 days, oregano essential oil exerted an anticoccidial effect against E. tenella, which was, however, lower than that exhibited by lasalocid. Supplementation with dietary oregano oil to E. tenella–infected chickens resulted in body weight gains and FCRs not differing from the noninfected group, but higher than those of the infected control group and lower than those of chickens treated with the anticoccidial lasalocid (Giannenas et al., 2003).
The Challenge of Parasite Control
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2015
Eric S. Loker, Bruce V. Hofkin
Eimeria tenella is a serious pathogen of chickens and can cause high mortality, especially in young birds. Only chickens are affected by this coccidian, which has developed resistance against most available drugs. Yet a vaccine that offers at least partial protection has been available since 1952, when Coccivac®, the first commercial vaccine against a eukaryotic pathogen, was released. This attenuated vaccine consisted of oocysts from several E. tenella strains, variants of which are still used today. Recently, the first subunit vaccine to target a eukaryote, CoxAbic®, has entered the market. This vaccine is composed of purified macrogametocyte antigens. Vaccinated birds respond by generating high titers of IgY (the avian equivalent to mammalian IgG).
Chicken toll-like receptors and their significance in immune response and disease resistance
Published in International Reviews of Immunology, 2019
Aamir Nawab, Lilong An, Jiang Wu, Guanghui Li, Wenchao Liu, Yi Zhao, Qimin Wu, Mei Xiao
Eimeria are parasites that cause coccidiosis in poultry species which, in turn, reduce productivity and result in major economic losses to the commercial poultry. Commonly, live vaccines and chemoprophylaxis are used to control coccidiosis in birds [129], but, due to the issue of drug resistance many of the anticoccidial drugs are ineffective and live parasite vaccine have many disadvantages such as less shelf life, safety associated concerns and large-scale production. Thus, efforts have been made to introduce a new and safe vaccine with a suitable adjuvant for a better immune response [130]. TLR ligands have been used as recombinant protein antigens to increase the immune response to the vaccine. A study by Dalloul et al. has showed that TLR21 ligand CpG enhanced the poultry resistance to coccidiosis [131]. CpG-ODN 2006 treatment decreased the number of oocyst, improved weight gain as well as the immunity of the birds. A study has tested the immunoprotective role of CpG in ovo and with an Eimeria recombinant microneme protein-2 (MIC2) [134]. The results of above reports found that oocyst shedding was reduced after in ovo administration of CpG-ODN and resistance against Eimeria acervulina infections was improved [134]. Furthermore, CpGODNs (ODN 2006 and ODN D19) administration with MIC2 reduced oocyst shedding, but the weight gain was increased only in ODN D19 treatment under Eimeria tenella-infection [134]. Hence, the immunoprotective ability of CpG-ODN was dependent on dose, route, backbone and on the chicken strain.
Steroid sulfatase inhibitors: the current landscape
Published in Expert Opinion on Therapeutic Patents, 2021
Hanan S. Anbar, Zahraa Isa, Jana J. Elounais, Mariam A. Jameel, Joudi H. Zib, Aya M. Samer, Aya F. Jawad, Mohammed I. El-Gamal
Recent patents about therapeutic uses of irosustat have been applied or registered. One patent has reported potential therapeutic value of irosustat for treatment or prevention of neurodegenerative disorders[91]. It was also reported as a potential agent for aging treatment [92,93]. In addition, a Chinese group report that irosustat can be used for treatment of eimeria tenella in veterinary use[94]. Irosustat is currently under consideration in clinical trial for treatment of hormone-dependent breast, endometrial, and prostate cancers[95].
Role of Mushroom as Dietary Supplement on Performance of Poultry
Published in Journal of Dietary Supplements, 2019
Sohail Hassan Khan, Nasir Mukhtar, Javid Iqbal
Avian coccidiosis is the major parasitic disease of poultry with substantial economic burden to the industry. Coccidiosis is caused by several apicomplexan parasites of the genus Eimeria that infect the intestinal tract and are transmitted between birds via ingestion of infective oocysts. Different studies have investigated the immunopotentiating effect of a mushroom on poultry cell-mediated immunity and subsequent protection against coccidiosis. Guo et al. (2004, 2005) demonstrated the protective effects of mushrooms and their polysaccharide extracts (Lentinus edodes and Tremella fuciformis) against Eimeria tenella infection. Dalloul, Lillehoj, Lee, Lee, & Chung (2006) investigated the immunopotentiating effect of a mushroom lectin extracted from mushroom (Fomitella fraxiena) on poultry cell-mediated immunity and protection against coccidiosis. When extract injected into 18-day-old chicken embryos followed by a posthatch oral E. acervulina challenge infection, lectin treatment significantly protected chickens against weight loss associated with coccidiosis. Injecting embryos with lectin also resulted in significant reduction in oocyst shedding as compared with the control saline-injected birds. Their results from utilizing the mushroom lectin included effective growth promotion and immune stimulation in poultry with coccidiosis. In a recent study conducted by Willis et al. (2012), four different medicinal mushrooms (shiitake, cordyceps, reishi, and oyster) were utilized for their potential immunomodulating properties in Eimeria-challenged broiler chickens. These workers evaluated the effects of feeding 5% each of four different medicinal mushrooms, both singularly and combined, via fungus myceliated grain (FMG) to broilers challenged with Eimeria at 14 days of age and reared in battery brooder cages. The major findings in this study demonstrated that broilers fed 5% shiitake via FMG were superior in their performance and Eimeria protection as opposed to broilers supplemented with reishi, oyster, or cordyceps or a combination of all four. Cordyceps was found to cause some depression in broiler body weights whether or not the bird was experimentally challenged with Eimeria at the time; however, it also showed the ability to significantly reduce oocyst shedding.