بررسي ضايعات آسيب‌شناسي آبشش سياه در ميگوي سفيد غربي (Litopenaeus vannamei) در مزارع پرورشي استان بوشهر

Histopathological observation of black gill disease in shrimp farm, Litopenaeus vannamei, in Boushehr province, Iran

ﻫﺪف از اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﺮرﺳﯽ ﺿﺎﯾﻌﺎت ﺑﺎﻓﺘﯽ ﻧﺎﺷﯽ از ﺑﯿﻤﺎري آﺑﺸﺶ ﺳﯿﺎه و ﻋﻠﻞ اﯾﺠﺎدﮐﻨﻨﺪه آن در ﻣﯿﮕﻮﻫﺎي ﭘﺮورﺷﯽ ﺳﻔﯿﺪ ﻏﺮﺑﯽ )Litopenaeus vannamei( 80-85 روزه ﺑﺎ ﻣﯿﺎﻧﮕﯿﻦ وزﻧﯽ 13-15 ﮔﺮم واﻗﻊ در ﻣﺠﺘﻤﻊ ﭘﺮورش ﻣﯿﮕﻮي دﻟﻮار اﺳﺘﺎن ﺑﻮﺷﻬﺮ در ﻃﻮل ﻣﺎه ﻫﺎي ﻣﺮداد ﺗﺎ ﺷﻬﺮﯾﻮر 1396 اﻧﺠﺎم ﺷﺪ. ﺑﺮرﺳﯽ ﻻم ﻣﺮﻃﻮب و ﻣﻘﺎﻃﻊ ﺑﺎﻓﺘﯽ ﺗﻬﯿﻪ ﺷﺪه از آﺑﺸﺶ ﻣﯿﮕﻮﻫﺎي ﻣﺒﺘﻼﺑﻪ آﺑﺸﺶ ﺳﯿﺎه ﺣﺎﮐﯽ از ﻧﮑﺮوز ﺷﺪﯾﺪ ﻻﻣﻼﻫﺎي اوﻟﯿﻪ و ﺛﺎﻧﻮﯾﻪ ﺑﻪ ﻫﻢ رﯾﺨﺘﮕﯽ ﻣﺤﻮر ﻣﺮﮐﺰي ﻻﻣﻼﻫﺎي آﺑﺸﺸﯽ ﻫﻤﺮاه ﺑﺎ ازﻫﻢ ﭘﺎﺷﯿﺪﮔﯽ و ﻣﺘﻮرم ﺷﺪن رﺷﺘﻪ ﻫﺎي آﺑﺸﺸﯽ ﺑﻮد. ﻫﻤﭽﻨﯿﻦ در ﻻﻣﻼﻫﺎي ﺛﺎﻧﻮﯾﻪ ﻋﻼوه ﺑﺮ ﭼﺴﺒﻨﺪﮔﯽ رﺷﺘﻪ ﻫﺎي آﺑﺸﺸﯽ، ﺗﺠﻤﻊ ﺳﻠﻮل ﻫﺎي ﺧﻮﻧﯽ در اﻧﺘﻬﺎي ﻻﻣﻼﻫﺎ ﻣﺸﺎﻫﺪه ﺷﺪ. ﻧﮑﺮوز ﺳﻠﻮل ﻫﺎي اﭘﯽ ﺗﻠﯿﺎل ﺑﺎ ﻣﺘﺮاﮐﻢ و ﺗﮑﻪ ﺗﮑﻪ ﺷﺪن ﻫﺴﺘﻪ ﺳﻠﻮل ﻫﺎ ﻫﻤﺮاه ﺑﺎاﺗﺼﺎل اﻧﮕﻞ ﺗﮏ ﯾﺎﺧﺘﻪ اﭘﯿﺴﺘﯿﻠﯿﺲ )Epistylis( از ﻋﻼﺋﻢ ﺑﺎرز آﺳﯿﺐ ﺷﻨﺎﺳﯽ آﺑﺸﺶ ﻫﺎ ﺑﻮد. ﺣﻀﻮر ﺑﺎﻻي ﺗﮏ ﯾﺎﺧﺘﻪ اﭘﯿﺴﺘﯿﻠﯿﺲ ﺑﺎ ﺷﯿﻮع 84/58 درﺻﺪ در ﺑﺎﻓﺖ آﺑﺸﺶ ﻧﺸﺎن دﻫﻨﺪه ﺷﺮاﯾﻂ ﻣﻨﺎﺳﺐ ﺑﺎﻓﺖ آﺑﺸﺸﯽ آﺳﯿﺐ دﯾﺪه ﺑﺮاي ﮐﻠﻮﻧﯿﺰه ﺷﺪن اﯾﻦ ﺗﮏ ﯾﺎﺧﺘﻪ ﻣﯽ ﺑﺎﺷﺪ. ﻫﻤﭽﻨﯿﻦ اﻓﺰاﯾﺶ رﺳﻮب ﻓﯿﺘﻮﭘﻼﻧﮑﺘﻮن ﻫﺎي ﺗﻠﻒ ﺷﺪه و ﺿﺎﯾﻌﺎت ﻧﺎﺷﯽ از ﻓﻮﻟﯿﻨﮓ ﺑﺮ روي رﺷﺘﻪ ﻫﺎي آﺑﺸﺸﯽ ﺑﻪ ﻋﻨﻮان ﻋﺎﻣﻞ ﺗﺸﺪﯾﺪﮐﻨﻨﺪه ﺑﯿﻤﺎري ﻣﺤﺴﻮب ﻣﯽ ﮔﺮدد. ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ ﺑﻪ دﺳﺖ آﻣﺪه ﻣﯽ ﺗﻮان اذﻋﺎن ﮐﺮد ﮐﻪ ﺗﮏ ﯾﺎﺧﺘﻪ ﻫﺎ ﺑﻪ ﻋﻨﻮان ﯾﮏ ﻋﺎﻣﻞ اﯾﺠﺎدﮐﻨﻨﺪه ﺑﯿﻤﺎري آﺑﺸﺶ ﺳﯿﺎه، در ﻣﯿﮕﻮﻫﺎي ﺳﻔﯿﺪ ﻏﺮﺑﯽ ﭘﺮورﺷﯽ )L.vannamei( ﻣﺰارع ﭘﺮورش ﻣﯿﮕﻮي دﻟﻮار اﺳﺘﺎن ﺑﻮﺷﻬﺮ ﻣﻄﺮح ﻣﯽ ﺑﺎﺷﻨﺪ. ﺑﺎ ﺗﻮﺟﻪ ﺑﺎاﯾﻨﮑﻪ آﺑﺸﺶ ﺳﯿﺎه درواﻗﻊ ﺗﻮﺳﻂ ﻋﻮاﻣﻞ ﻣﺤﯿﻄﯽ و ﻋﻔﻮﻧﯽ ﻣﺘﻌﺪدي ازﺟﻤﻠﻪ ﻋﻮاﻣﻞ ﻗﺎرﭼﯽ و ﺑﺎﮐﺘﺮﯾﺎﯾﯽ ﻣﯽ ﺗﻮاﻧﺪ اﯾﺠﺎد ﺷﻮد، ﻟﯿﮑﻦ در اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﻫﯿﭻ ﮔﻮﻧﻪ ﻋﺎﻣﻞ ﺑﯿﻤﺎري زاي دﯾﮕﺮي ﺟﺪاﺳﺎزي ﻧﺸﺪ. ازاﯾﻦ رو در ﻣﻄﺎﻟﻌﺎت ﺑﻌﺪي ﺑﻪ ﺗﺤﻘﯿﻘﺎت ﺟﺎﻣﻊ ﺗﺮي ﺑﻪ ﻣﻨﻈﻮر ﺟﺪاﺳﺎزي و ﺷﻨﺎﺳﺎﯾﯽ ﻋﺎﻣﻞ اوﻟﯿﻪ ﺑﯿﻤﺎري ﺑﻪ ﻣﻨﻈﻮر ﻣﺪﯾﺮﯾﺖ ﺑﻬﺪاﺷﺘﯽ و درﻣﺎن ﻧﯿﺎز اﺳﺖ.

The aim of this study was evaluate tissue lesions caused by black gill disease and its causes in 85-80 days old Litopenaeus vannamei with an average weight of 13-15 g located in the Delvar shrimp rearing site from Bushehr province. Primary and secondary gill lamella was necrosis, central axis were not arranged and gill lamella swelling, epithelial cell necrosis along with karyorrhexis and pyknosis of gill lamella was observed in wet mouth examination and tissue sections. Also, Epistylis protozoan parasite were observed in gill tissue. The high prevalence of Epistylis protozoa (84.58%) in gill tissue, indicates the proper condition of gill tissue for colonization of this parasite. Increased sedimentation of phytoplankton and folding on the gill tissues is considered as an exacerbating factor in the disease. Based on the results, it can be admitted that Epistylis protozoan parasite can be a factor cause of black gill disease in L. vannamei shrimp farms of Delvar shrimp rearing site from Boushehr province. On the other hand, black gill can be caused by several environmental and infectious agents, including fungal and bacterial agents, but in this study were not detected any other pathogen. Hence, in further studies, more comprehensive research is needed to isolate and identify the primary cause of the disease for the management of health and treatment.