جستجوی مقالات مرتبط با کلیدواژه « جوجه های SPF » در نشریات گروه « دامپزشکی »

The purpose of this study was to evaluate the type, severity and extent of tissue lesions induced by secondary infection with avian influenza virus following inoculation by ORT in SPF chickens. Sixty, one-day-old SPF chicks were provided and divided randomly into three groups. At the age of 21 days, the chicks in the first group were inoculated only with ORT and second group inoculated first with ORT and three days later with H9N2 virus. Each bird in third group was received only with PBS as control. Tissue samples were taken from trachea, lungs, liver, kidneys, bursa of fabricius, thymus, spleen and cecal tonsils for histopathological studies and after preparation and tissue sections were stained by Hematoxylin and Eosin (H&E) method. In chickens of the first group, ORT bacteria in addition to cause tissue lesions in organs of the respiratory system (loss of cilia with infiltration of mononuclear cells under the mucosa in the trachea, hyperemia and pneumonia in the lung), liver (congestion of sinusoids and central veins) and the kidneys (Hemorrhage and necrosis of urinary tubes) in  immune system organs also cause tissue lesions such as lymphocyte depletion in the bursa of fabricius, congestion and heterophil infiltration in thymus and increase in the of lymphoid follicles in the spleen and cecal tonsils. The histopathological lesions in chickens of the second group was more severe and longer than that of the first group. Tissue changes were not observed in control group. The results of this study showed that in chickens inoculated by ORT and under secondary infection with avian influenza virus cause exacerbate and lunge histopathological lesions induced by ORT.

The purpose of this study was to investigate effect of secondary infection with avain influenza virus subtype H9N2 on tissue tropism and dissemination of ornithobacterium rhinotracheale (ORT) bacteria and H9N2 AI virus in different organs of specific pathogen free (SPF) chickens. Sixty, oneday- old SPF chicks ‘were randomly divided into three groups. They were kept in separate positive pressure isolators. On 21st day of study, the chicks in group 1 was inoculated intratracheally with 1×1010 CFU of ORT and three days later were adminstrated intraocularly with 1×106 EID50 of the H9N2, group 2 only inoculated with ORT bacteria. Group 3 as control was inoculated with PBS’ intraocularly. The samples from various tissues were collected at 6, 8, 10, 12, 14 and 16 days postinoculation (DPI). In group 1 chickens exhibited ruffled feathers, depression and reduced appetite, while in group 2 had minor clinical signs depression. The H9N2 AI virus was detected from lungs, trachea, bursa of fabricius, thymus, spleen and cecal tonsils of first group birds. The ORT was detected in the trachea, lung and liver of infected groups. The results showed that infected chickens with ORT under secondary infection by H9N2 AI virus cause exacerbate virulence and clinical signs and lesions
of ORT.

The purpose of this study was to investigate effect of secondary infection with Ornithobacterium rhinotracheale (ORT) on pathogenesis of avain influenza virus subtype H9N2 in specific pathogen-free (SPF) chickens. Sixty, one-day-old SPF chicks were randomly divided into three groups. They were kept in separate positive pressure isolators. On 21st day of study, the chicks in group 1 was infected intraocularly with 1×106 EID50 of H9N2 and three days later intratracheally with 1× 1010 CFU of ORT, group 2 only inoculated with H9N2 AI virus, intraocularly. Control group was inoculated with PBS, intraocularly. The samples from various tissues were collected at 6, 8, 10, 12, 14 and 16 days post-inoculation (DPI). In first group chickens exhibited ruffled feathers, depression, respiratory signs, reduced appetite and 10% mortality. The most remarkable clinical signs appeared on day 5 PI. While in second group had minor clinical signs. The H9N2 virus was not detected from organs of group 1 with increasing antibody except lungs of died bird on days 5 PI. The ORT was detected in the trachea and lungs on days 6 and 8 PI. The bacteria was also found in the heart and liver on day 8 PI and in trachea of died birds on days 5 and 7 PI. The results showed that infected chickens with the H9N2 AI virus under secondary infection by ORT cause exacerbate virulence and lesions of H92.

Ornithobacteriosis is caused by Ornithobacterium rhinotracheale (ORT) that can cause economic losses to the poultry industry annually. The purpose of this study was to investigate tissue tropism and dissemination of ORT-R87-7/1387 strain of ORT in different organs of experimentally infected SPF chickens. Forty one-day-old SPF leghorn chicks were provided and divided randomly into two groups (20 chicks in the experimental and 20 chicks in the control group). They were kept in separate positive pressure isolators. At the age of three weeks، the chicks in the experimental group were inoculated intratracheally with 1× 1010 CFU of ORT. Each bird in control group was inoculated with PBS. The sample from trachea، lungs، liver and heart were collected at 2،4،6،8،10،12 and 14 days post-inoculation (PI). Three chickens of experimental group showed ruffled feathers from days 3 to 4 PI that this signs disappeared at 5 day PI. ORT was isolated in the trachea on days 2،4، 8 and 10 PI. The bacteria was also found in the lungs and liver on day 4 PI. But ORT was not detected in samples taken from heart during study. The results showed that this strain of ORT alone can not lead to mortality، severe clinical signs or gross lesions in infected chickens، but its replication in the trachea for a long time could render birds susceptible to other diseases.

Avian infectious bronchitis virus (IBV) is an important pathogen in poultry flocks, that primarily induces respiratory diseases, but different IBV strains may also affect the other tissues. The aim of this study was to investigate the tissue tropism of avian infectious bronchitis virus strain 793/B in experimentally infected SPF chickens by RT-PCR and Nested-PCR assays. In this study, tissue dissemination of Iranian isolate IR/773/2001(793/B) of IBV in different organs of SPF chickens was studied. Forty two one-day-old SPF chicks were divided randomly into two groups (21chicks per group). At the age of 12 days old the chicks in group1 were inoculated intra-ocularly with 103EID50 of the 793/B isolate, and group2 was control group. The samples from various tissues were collected at 2, 4, 6, 8, 10 and 12 days post-inoculation (PI). The chicks of infected group exhibited depression at 2 to 4 days PI. The IBV virus was detected in the cecal tonsils and cloaca from days 2-12 PI. Also virus detected in kidneys from days 4-10 PI, and in Bursa of fabricius from 4-12 days PI. In the trachea virus was detected on days 2 and 4 PI and in thymus samples virus was detected on days 6 and 8 PI. The positive sample from the lungs only was at day 4 PI. The results of this study indicated that the 793/B serotype of IBV cannot cause mortality, sever clinical signs or gross lesions in infected chickens, but its replication in some tissues could expose birds to other micro-organisms.