تاثیر فرآوری کاه گندم با استفاده از کشت مایع و جامد قارچ شیزوفیلوم کمون بر ترکیب شیمیایی، تجزیه‌پذیری شکمبه‌ای و گوارش پذیری و تولید گاز در شرایط برون‌تنی

زمینه مطالعاتی: امروزه استفاده از قارچ‌های بازیدومیستی به دلیل ترشح آنزیم‌های تجزیه‌کننده لیگنین در فراوری خوراک‌های حاوی مقدار زیاد لیگنین مورد توجه قرار گرفته است. هدف: در این تحقیق ترکیب شیمیایی، حجم گاز تولیدی، تجزیه‌پذیری ماده خشک و تجزیه‌پذیری الیاف نامحلول در شوینده خنثی کاه گندم فراوری شده با قارچ شیزوفیلوم کمون به‌صورت کشت مایع و کشت جامد مورد مطالعه قرار گرفت. روش‌کار: به‌منظور فراوری، قارچ‌ رشد یافته در محیط کشت جامد و محیط کشت مایع حاوی آنزیم‌های مترشحه پس از فیلتراسیون قارچ‌های روئی مایع و به درون محفظه شیشه‌ای حاوی کاه گندم استریل و خیس شده تلقیح و به مدت 25روز در دمای 26 درجه سانتی‌گراد نگهداری شد. میزان تولید گاز تیمار‌ها در ویال‌های شیشه‌ای و تجزیه‌پذیری با استفاده از کیسه‌های نایلونی و سه راس گاو هلشتاین فیستولا گذاری شده، اندازه‌گیری گردید. نتایج: با فراوری کاه گندم توسط قارچ شیزوفیلوم کمون به‌صورت کشت مایع و جامد مقدار ماده خشک و الیاف نامحلول در شوینده خنثی کاهش و مقدار پروتئین خام، الیاف گوارش ناپذیر نامحلول در شوینده خنثی افزایش یافت. فرآوری با قارچ سبب افزایش قابلیت تخمیر و افزایش کل اسیدهای چرب فرار تولیدی و نیتروژن آمونیاکی شد. فراوری به روش کشت جامد قارچی سبب افزایش حجم گاز تولیدی و تجزیه‌پذیری ماده خشک کاه گندم شد ولی تاثیر معنی‌داری بر تجزیه‌پذیری الیاف نامحلول در شوینده خنثی نداشت. تجزیه پذیری الیاف نامحلول در شوینده خنثی کاه گندم فراوری شده با هر دو روش کشت کاهش یافت. نتیجه‌گیری نهایی: به‌طورکلی فراوری کاه گندم با قارچ شیزوفیلوم به روش کشت جامد سبب بهبود برخی مولفه‌های تغذیه‌ای شد، اما افزودن محیط کشت مایع قارچی تاثیر مثبت معنی‌داری در افزایش ارزش تغذیه‌ای کاه گندم نداشت.

the effect of wheat straw processing using liquid- and solid-state culture of schizophyllum commune on chemical composition, in vitro digestibility and fermentation parameters and rumen degradability

introduction: today, one of the most important problems in the livestock industry is related to the high cost of feed and their low quality. annually, a large amount of agricultural residues are produced in countries around the world, including iran. these agricultural residues are important foods in the diet of ruminants. however, the use of these products as a food source in the diet of ruminants is limited due to limitations in their complex biological structure and low protein. today, there is a great interest in using straws as agricultural by-products to feed ruminants in many asian countries, because on the one hand, the cost of quality fodder is high and on the other hand, access to this fodder is limited. these by-products are often referred to as lignocellulose because they contain a lot of cellulose that is bonded with the lignin biopolymer. it is believed that this large amount of fiber has a negative correlation with the optional consumption of feed, the fermentation rate of organic matter, the amount of microbial cells per unit of fermented organic matter and the ratio of acetate to propionate. therefore, processing these by-products before consumption is very necessary. different physical, chemical and biological methods have been used to process wheat straw, all of which aim to break down lignin and make more cellulose and hemicellulose available for fermentation in the rumen. the use of biological processing methods by fungi has received more attention due to the lack of environmental pollution. white rot fungi are the only organisms capable of aerobically degrading lignin to co2 and water. degradation of lignin by white rot fungi relies on three enzymes: lignin peroxidase, manganese peroxidase and lacase. schizophyllum commune is an edible fungus of the basidiomycete’s family. the level of enzyme produced in this fungus is significantly affected by the incubation time of the substrate with the fungus. spraying of lacase enzyme from schizophyllum (liquid culture lacase, solid culture lacase and purified lacase) on wheat straw, corn straw and sorghum straw gradually reduces the amount of neutral detergent fiber of straws and as a result, it increases the digestibility of straws. the purpose of this experiment was to determine the chemical composition, volume of gas produced, dry matter degradability, degradability of neutral detergent fiber and volatile fatty acids produced by wheat straw processed with schizophyllum commune under liquid culture and solid culture using nylon bags and gas production method.material and methods: to process wheat straw, the straw was first soaked in water for 12 hours and then sterilized in an autoclave at 121 ° c for 20 minutes. for solid culture, a 7-day-old mushroom was transferred to each jar containing sterilized wheat straw and stored at 26 ° c for 25 days. liquid culture medium containing the secreted enzymes was inoculated after filtration of the fungi on the liquid and into a glass chamber containing sterile and soaked wheat straw and kept at 26 ° c for 25 days. wheat straw was removed from the jars after 25 days and dried for 4 days at 60 ° c. the gas production of the treatments in glass vials at 2,4,6,8,12,24,48,72,96,120,144 hours and their degradability were measured using nylon bags and three holstein cows fistulated at 2,4,6,8,12,24,48,72,96 hours of ruminal incubation.results and discussion: processing of wheat straw by schizophyllum commune reduced dry matter and neutral detergent fiber. solid culture and liquid culture increased the amount of protein from 2.94 to 6.12 and 5.7%, respectively. cumulative gas production increased during 144 hours of incubation in wheat straw processed by solid culture. organic matter digestibility percentage, dry matter digestibility percentage and metabolisable energy in wheat straw processed by liquid culture method showed a significant increase. the amount of crude microbial protein in wheat straw processed by liquid culture method showed a significant increase. dry matter degradability increased during 96 hours of ruminal incubation and the potentially fermentable portion of processed wheat straw by solid culture. there was no significant difference between different treatments in terms of nutritional value index. the degradability of neutral detergent fiber was reduced during 96 hours of incubation and the effective degradability in the treated groups was reduced. liquid and solid culture processing increased the total amount of volatile fatty acids and ammonia nitrogen in wheat straw.conclusion: in general, processing of wheat straw with schizophyllum by solid culture method improved some nutritional components, but the addition of fungal liquid culture medium did not have a significant positive effect on increasing the nutritional value of wheat straw.