کلیباسیلوز شایعترین بیماری باکتریایی در صنعت طیور جهان است که همه ساله خسارات سنگینی به صنعت مرغداری کشورمان وارد میکند. باکتری اشریشیا کُلی به عنوان عامل کلیباسیلوز شناخته شده است. جهت کنترل این بیماری عموماً از آنتیبیوتیک استفاده میشود؛ اما مقاومتهای آنتیبیوتیکی به وجود آمده در سالهای اخیر، کنترل بیماری را با چالش رو به رو کرده است. در این شرایط، پیشگیری از بیماری با استفاده از واکسن، ضمن ایجاد ایمنی در برابر بیماری، مانع گسترش مقاومتهای آنتیبیوتیکی و کاهش خسارت ناشی از ابتلای جوجهها به بیماری کلیباسیلوز خواهد شد. با توجه به این که باکتریهای اشریشیا کلی بیماریزای پرندگان، سویههای مختلفی دارد و بین آنها ایمنی هترولوگ وجود ندارد، واکسنی که بتواند ایمنی هترولوگ ایجاد کند از اهمیت بالایی برخوردار است. در این مطالعه ایمنی متقاطع واکسن کشتهی تریوالان کلیباسیلوز، متشکل از سه سروتیپ بیماریزای O78:K80، O2:K1 و O1:K1 اشریشیا کلی جدا شده از مرغداریهای ایران به همراه ادجوانت آلوم، علیه یک سویهی هترولوگ (سروگروپ بیماریزای O18) در 80 قطعه جوجهی گوشتی مورد بررسی قرار گرفت. بدین منظور جوجهها به صورت تصادفی به چهار گروه تقسیم شدند؛ دو گروه در سن 10 روزگی واکسن را به صورت زیرجلدی، در ناحیهی پشت گردن دریافت کردند. یک گروه واکسینه و یک گروه غیر واکسینه به صورت تصادفی در سن 35 روزگی انتخاب و به روش داخل نایی با باکتری ایکلای سروگروپ O18 چالش داده شدند. در طول مطالعه، علائم بالینی، کالبدگشایی، درصد تلفات، میزان غذای مصرفی روزانه، میزان رشد هفتگی و ضریب تبدیل غذایی به دقت ثبت شد؛ همچنین جهت سنجش عیار آنتیبادی سرم خون جوجهها بر علیه آنتی ژن O، 4 سویهی اشریشیا کلی (O78:K80، O2:K1 ،O1:K1 و O18)، به صورت هفتگی خونگیری انجام گرفت. بر اساس نتایج به دست آمده در سن 28 روزگی (18 روز بعد از واکسیناسیون)، عیار آنتیبادی علیه آنتیژن O سه سویهی موجود در واکسن ایجاد شده و این عیار آنتیبادی تا سن 42 روزگی جوجههای واکسینه به صورت معنیداری همچنان بالا بود. بین دادههای حاصل از سنجش میزان دان مصرفی، وزن هفتگی، میزان رشد هفتگی و ضریب تبدیل غذایی قبل و بعد از چالش بین گروهها اختلاف آماری معنیداری وجود نداشت؛ با این حال گروه واکسینهی چالش داده شده عملکرد بهتری نسبت به گروه غیر واکسینهی چالش داده شده داشت. بعد از چالش تنها یک مورد تلفات (5%) از گروه غیر واکسینه گزارش شد که پریکاردیت فیبرینی چرکی را در کالبدگشایی لاشه نشان داد که احتمالاً بیانگر درگیری جوجه با بیماری کلیباسیلوز بود. علاوه بر این علائم، بیاشتهایی، اسهال و مدفوع سبز رنگ در گروه غیر واکسینهی چالش داده شده مشاهده گردید؛ این در حالیست که گروه واکسینهی چالش داده شده هیچ گونه علائم بالینی مبنی بر درگیری با بیماری از خود نشان نداد. بنابراین به نظر میرسد واکسن تریوالان کلیباسیلوز طیور توانسته است به خوبی ایمنی متقاطع علیه سروگروپ O18 ایجاد کند و مانع تلفات و بروز علائم بالینی در گروه واکسینه شود.
متن يادداشت
Colibacillosis is the most common bacterial disease in the poultry industry, which causes heavy losses in our country every year. Escherichia coli is known as the cause of colibacillosis. Antibiotics are generally used to control this disease, but the antibiotic resistance that has emerged in recent years has made controlling the disease a challenge. In this situation, disease prevention by using a vaccine, while creating immunity against the disease, will prevent the spread of antibiotic resistance and reduce the damage caused by chickens suffering from the general disease of colibacillosis. because Escherichia coli bacteria that are pathogenic to birds have different strains and there is no heterologous immunity between them, a vaccine that can create heterologous immunity is of great importance. In this study, the cross immunity of trivalent avian colibacillosis vaccine, consisting of three pathogenic serotypes O78:K80, O2:K1 and O1:K1 Escherichia coli isolated from poultry farms in Iran along with alum adjuvant, against a heterologous strain (pathogenic serogroup O18) It was investigated in 80 broilers chicken. For this purpose, the chickens were randomly divided into four groups; Two groups received the vaccine subcutaneously in the back of the neck at the age of 10 days. A vaccinated group and a non-vaccinated group were randomly selected at the age of 35 days and challenged intratracheally with E.coli serogroup O18. During the study of clinical symptoms, necropsy, death percentage, daily food intake, weekly growth rate and food conversion rate were carefully recorded; Also, to measure the blood serum antibody level of chickens against O antigen, 4 strains of Escherichia coli (O78:K80, O2:K1, O1:K1 and O18), weekly blood sampling was done. According to the results at the age of 28 days (18 days after vaccination), the antibody titer against the three-strain O antigen in the vaccine was created, and this antibody titer remained significantly high until the age of 42 days in the vaccinated chickens. There was no statistically difference between the data obtained from measuring the amount of feed consumed, weekly weight, weekly growth rate and food conversion ratio before and after the challenge between the groups; However, the vaccinated group that was given the challenge performed better than the non-vaccinated group that was given the challenge. After the challenge, only one death case (5%) was reported from the non-vaccinated group, and purulent fibrinous pericarditis was observed in the necropsy of the carcass, which was probably an indication of the involvement of the chicken with the general colibacillosis. In addition to these symptoms, anorexia, diarrhea, and green stools were observed in the non-vaccinated and challenged group; Meanwhile, the vaccinated group did not show any clinical symptoms related to the disease. Therefore, it seems that the trivalent avian colibacillosis vaccine has been able to create cross immunity against serogroup O18 and prevent the deaths and occurrence of clinical symptoms in the vaccinated group.
عنوانهای گونه گون دیگر
عنوان گونه گون
Colibacillosis is the most common bacterial disease in the poultry industry, which causes heavy losses in our country every year. Escherichia coli is known as the cause of colibacillosis. Antibiotics are generally used to control this disease, but the antibiotic resistance that has emerged in recent years has made controlling the disease a challenge. In this situation, disease prevention by using a vaccine, while creating immunity against the disease, will prevent the spread of antibiotic resistance and reduce the damage caused by chickens suffering from the general disease of colibacillosis. because Escherichia coli bacteria that are pathogenic to birds have different strains and there is no heterologous immunity between them, a vaccine that can create heterologous immunity is of great importance. In this study, the cross immunity of trivalent avian colibacillosis vaccine, consisting of three pathogenic serotypes O78:K80, O2:K1 and O1:K1 Escherichia coli isolated from poultry farms in Iran along with alum adjuvant, against a heterologous strain (pathogenic serogroup O18) It was investigated in 80 broilers chicken. For this purpose, the chickens were randomly divided into four groups; Two groups received the vaccine subcutaneously in the back of the neck at the age of 10 days. A vaccinated group and a non-vaccinated group were randomly selected at the age of 35 days and challenged intratracheally with E.coli serogroup O18. During the study of clinical symptoms, necropsy, death percentage, daily food intake, weekly growth rate and food conversion rate were carefully recorded; Also, to measure the blood serum antibody level of chickens against O antigen, 4 strains of Escherichia coli (O78:K80, O2:K1, O1:K1 and O18), weekly blood sampling was done. According to the results at the age of 28 days (18 days after vaccination), the antibody titer against the three-strain O antigen in the vaccine was created, and this antibody titer remained significantly high until the age of 42 days in the vaccinated chickens. There was no statistically difference between the data obtained from measuring the amount of feed consumed, weekly weight, weekly growth rate and food conversion ratio before and after the challenge between the groups; However, the vaccinated group that was given the challenge performed better than the non-vaccinated group that was given the challenge. After the challenge, only one death case (5%) was reported from the non-vaccinated group, and purulent fibrinous pericarditis was observed in the necropsy of the carcass, which was probably an indication of the involvement of the chicken with the general colibacillosis. In addition to these symptoms, anorexia, diarrhea, and green stools were observed in the non-vaccinated and challenged group; Meanwhile, the vaccinated group did not show any clinical symptoms related to the disease. Therefore, it seems that the trivalent avian colibacillosis vaccine has been able to create cross immunity against serogroup O18 and prevent the deaths and occurrence of clinical symptoms in the vaccinated group.
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