تاثير كمبود متيونين جيره بر بافت‌ شناسي روده باريك بلدرچين ژاپني

Effect of methionine deficiency on small intestinal histology in Japanese quail

به­ منظور مطالعه تاثير كمبود متيونين جيره به عنوان يك اسيد آمينه حياتي بر بافت روده باريك،تعداد 20 قطعه بلدرچين ژاپني نر يك‌روزه به­ صورت تصادفي به 2 گروه 10 تايي تقسيم شدند. بلدرچين‌هاي گروه آزمايشي با جيره فاقد مكمل متيونين و گروه شاهد با جيره استاندارد بلدرچين به مدت 6 هفته تغذيه شدند. پس از پايان دوره و كشتار بلدرچين‌ها نمونه‌هاي بافت‌شناسي از قسمت مياني دوازدهه، تهي روده و ايلئوم تهيه و مراحل معمول بافت‌شناسي انجام پذيرفت. سپس برش­ هاي 6 ميكروني تهيه­ شده،تحت رنگ ­آميزي هماتوكسيلين-ائوزين و روش هيستوشيمي پريوديك اسيد چيف قرار گرفتند. با استفاده از نرم ­افزار Axio vixion Rel 4.8 ارتفاع و عرض كرك، عمق كريپت، نسبت ارتفاع كرك به عمق كريپت و تعداد سلول­ هاي جامي در واحد سطح اندازه‌گيري و داده‌ها به صورت ميانگين±انحراف معيار ارائه شده و با روش آماري Independent-Samples t-Testو در سطح معني­ p < 0/05 ;از لحاظ آماري مورد مقايسه قرار گرفتند. كاهش متيونين جيره سبب كاهش معني‌دار عرض كرك و تعداد سلول‌هاي جامي در هر سه قسمت روده باريك و نيز كاهش معني‌دار ارتفاع كرك و نسبت ارتفاع كرك به عمق كريپت در تهي‌روده شد. باتوجه به­ اين­كه كاهش نسبت ارتفاع كرك به عمق كريپت سبب كاهش سطح جذب در روده مي‌شود، مشخص گرديد كه كاهش متيونين جيره با اثر منفي بر سلول­هاي جامي و كاهش ترشحات مخاطي سبب آسيب به مخاط روده باريك و همچنين كاهش سطح هضم و جذب روده ­اي و در نهايت كاهش وزن بلدرچين مي‌شود.

Background and purpose: Japanese quail (Coturnix japonica) is a small size bird with big economical profits. This species is a good "dual-purpose" bird and is now reared for the meat and egg production. Quails have relatively early maturity and may be used as an experimental model due to their fast development, small size, etc. Moreover, because of high mortality due to emergence of new and reemergence of existing diseases in chickens, quails are being reared as they are more resistant to common poultry diseases. Methionine (Met) is a sulfur-containing amino acid with the biological functions including involvement in synthesis of eukaryotic proteins, defense against oxidative stress, methylation reactions and so on. Met also has a role in avian immune function and the nutrient digestibility in the intestine. Changes in small intestine morphology can alter absorption rate, weight gain and performance of the animal because of its important role in digestive tract for absorption. From the other point of view, alteration in the ingredients of diet may lead to a change in the intestinal mucosa and subsequently alteration in poultry performance. Thus, the aims of this study were to investigate the effect of Met deficiency on the development of the small intestine (duodenum, jejunum and ileum) and the goblet cell population in Japanese quails. Materials and methods: To evaluate the Met deficiency as a vital amino acid on histology of small intestine of Japanese quail, 20 male one-day old quails were randomly allocated into 2 groups of 10 birds. One group received Met deficient diet while another group of birds were kept as control with standard diet for 6 weeks. At the end of the experiment, all animals sacrificed by cervical dislocation. Whole length small intestine was removed immediately and immersed in 10% buffered formalin. After fixation, 1cm-thick samples were taken from the middle parts of duodenum (from the gizzard to pancreatic and bile duct), jejunum (from the bile duct to Meckel’s diverticulum) and ileum (from the Meckel’s diverticulum to ileo-cecal-colonic junction). After routine histological laboratory methods, 6μm-thick transverse cross-sections were made, a total number of 10 sections used from each intestinal segment of each bird; sections stained with Haematoxylin and Eosin and Periodic acid-Schiff. For measuring length and width of villi, depth of crypts and goblet cells number Axio vixion Rel 4.8 software were used. Data were expressed as Mean±SD. Data analysis was performed by Independent-Samples T Test method and differences considered statistically significant at p.