اثر سطوح مختلف روغن کتان بر عملکرد، تجزیه پذیری، برخی از فراسنجه های خونی و صفات کمی و کیفی گوشت در بره های پرواری

این تحقیق به منظور بررسی تاثیر مصرف سطوح مختلف روغن دانه کتان بر تجزیه پذیری، عملکرد، خصوصیات لاشه و فراسنجه های خونی در بره های پرواری انجام شد. در آزمایش اول، تجزیه پذیری شکمبه‌ای ماده خشک، پروتئین خام وndf جیره های آزمایشی با استفاده از روش کیسه نایلونی و با 3 راس گوسفند دارای فیستولای شکمبه ای نژاد زل تغذیه شده در حد نگهداری اندازه گیری شد. زمان های شکمبه گذاری در این آزمایش شامل زمان های صفر، 4، 8، 16، 24، 36، 48، 72 و 96 ساعت بود. نتایج نشان داد که تفاوت معنی داری در تجزیه پذیری ماده خشک و پروتئین خام بین تیمارها در این آزمایش مشاهده نشد. در آزمایش دوم، 16 راس بره نر (وزن 2±27 کیلوگرم و سن حدود پنج ماهگی) برای بررسی اثرات سطوح مختلف روغن کتان بر عملکرد، خصوصیات لاشه و فراسنجه های خونی، در قالب طرح کاملاً تصادفی با 4 جیره آزمایشی (حاوی صفر، 1.5، 3 و 4.5 درصد روغن کتان) به مدت 90 روز پروار شدند. جیره ها از نظر انرژی و پروتئین قابل متابولیسم مشابه بودند. جیره‌های آزمایشی اثر معنی‌داری بر خوراک مصرفی داشت، علاوه بر این بره های تغذیه شده با جیره حاوی 4.5 درصد روغن کتان بیشترین تاثیر منفی را بر قابلیت هضم مواد مغذی جیره کاملاً مخلوط نشان دادند. همچنین جیره حاوی روغن کتان باعث ایجاد اختلاف معنی‌دار در برخی از خصوصیات لاشه بره‌ها نسبت به تیمار شاهد شد. روغن کتان سبب افزایش سهم اسید لینولئیک، اسید لینولنیک و نسبت اسیدهای چرب غیراشباع با چند پیوند دوگانه به اسیدهای چرب اشباع چربی داخل ماهیچه ای در لاشه بره های پرواری شد. همچنین روغن کتان تاثیر معنی داری بر فراسنجه های خونی دام های پرواری داشت. نتیجه کلی حاصل از این تحقیق نشان داد که با افزایش سطح روغن کتان ، میانگین تجزیه پذیری الیاف نامحلول در شوینده خنثی، مصرف خوراک، و قابلیت هضم ظاهری مواد مغذی روند کاهشی داشت ولی در صفات کیفی لاشه بهبود حاصل شد.

Effect of different levels of linseed oil on performance, degradability, digestibility, some blood parameters, quantitative and qualitative traits of meat in fattening lambs

Introduction The extracted oil from linen contains about 50% linolenic acid from the family of omega3 fatty acids. Among edible sources, fish oil and linseed oil are a rich source of omega3 fatty acids. Linoleic acid and linolenic acid are a key factor in the normal growth and reproduction of animal, were not considered an important issue for animal nutrition. Essential fatty acids, including linoleic acid, linolenic acid and arachidonic acid, and in recent years the demand for foods with omega3 longchain fatty acid conjugated linoleic acid is high because of important biological role of these fatty acids in the body. Alphalinolenic acid is an essential fatty acid that cannot be manufactured by the human body, but are essential for the body 's metabolism. Although mammals cannot make omega3 fatty acids, but have limited functionality in the form of fatty acid. Linseed has a high linolenic acid as a substrate for the synthesis of longchain omega3 fatty acid that for the (EPA), which is the precursor for eicosanoids. Eicosanoid are similar compounds of hormones that play an essential role in the immune response. In addition, EPA can become (DHA), which is an essential fatty acid in cell tissue layers of the eye and brain. The objective of this study was to evaluate the effects of linseed oil on degradability, performance, carcass characteristics and some blood parameters in fattening lambs;Material and methods In first experiment, ruminal degradability of dry matter, crude protein, NDF and ADF were measured by nylon bag technique using three fistulated Zell sheep that fed at maintenance level. Incubation time consisted of 0, 4, 8, 16, 24, 36, 48, 72 and 96. The experimental animal were kept in individual cage and fed at 8 am and 20 pm with experimental diet to ratio of 70 to 30 forage to concentrate. In the second experiment, the effects of various levels of linseed oil on performance, carcass characteristics and blood parameters were studied. The performed experiment was completely randomized design (CRD) with four diets containing zero, 1.5, 3 and 4.5 percent linseed oil on 16 male lambs with initial average weight 27± 2 kg and 56 months old for 90 days. Energy and chemical composition of rations were similar. The experimental diet was balanced using the Small Ruminants Nutrition System (SRNS). Monthly weighing was carried out at the end of the experiment by applying 12 hours of starvation before weighing, and daily feed intake was used to calculate the feed conversion ratio. Data obtained were analyzed by statistical software SAS (version 1.9).;Results and discussion Dry matter degradability significantly affected by experimental treatments (P <0.05). However, the crude protein, NDF and ADF not observed significant difference between treatments. In first experiment, ruminal degradability of dry matter, crude protein, NDF and ADF were measured by nylon bag technique using three fistulated Zell sheep that fed at maintenance level. Incubation time consisted of 0, 4, 8, 16, 24, 36, 48, 72 and 96 h. Dry matter degradability and crude protein not observed significant difference between treatments. In the second experiment, experimental diets had significant effect on feed intake also results of the current experiment showed that linseed oil in 4.5% of dry matter had most negative effects on nutrient digestibility of total mixed ration (P < 0/05). Diet contained linseed oil and thyme oil affected some carcass characteristics significantly compared to other treatments (P <0/05). Linseed oil increased C18:3, C18:2 and P/S ratio (P <0.05). Linseed oil had a significant effect on the blood parameters of treatments.;Conclusion In general, degradation of dry matter results showed that adding linseed oil, had little effect on the degradation of dry matter and protein and numerically, was reduced compared to control. With increasing the level of linseed oil in the diet, the mean of NDF degradability, feed intake, and apparent digestibility of nutrients was a downward trend and did not improve these indices. In this study, adding linseed oil improved daily gain and feed conversion ratio compared to the control. The carcass fatty acids, omega3 fatty acids increased, which is an indicator of health. The overall result of this study showed that increasing the level of linseed oil decreased the average degradation of NDF, feed intake and digestibility of nutrients but improved the carcass quality traits.;;