نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی، دانشکده کشاورزی، دانشگاه شهرکرد، شهرکرد، ایران. رایانامه: khatamamini78@gmail.com
2 گروه علوم دامی، دانشکده کشاورزی، دانشگاه شهرکرد، شهرکرد، ایران. رایانامه: amirabadi@sku.ac.ir
3 نویسنده مسئول، بخش تحقیقات علوم دامی، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان چهارمحال و بختیاری، سازمان تحقیقات، آموزش و ترویج کشاورزی، شهرکرد، ایران. رایانامه: gtaasoli@gmail.com
4 گروه علوم دامی، دانشکده کشاورزی، دانشگاه شهرکرد، شهرکرد، ایران. رایانامه: saeid.karimi@sku.ac.ir
5 گروه علوم دامی، دانشکده کشاورزی، دانشگاه ملایر، ملایر، ایران. رایانامه: F.rezaei@malayeru.ac.ir
کلیدواژهها
عنوان مقاله English
نویسندگان English
Objective: Agricultural residues are part of ruminant diets, and it is necessary to optimize the use of these materials and minimize wastage through proper processing (treating) of these residues to improve palatability. Rice straw and rice bran are two major residues after harvesting and processing of rice, and chemical processing mostly improve their digestibility of the residues, due to the weakening hydrogen bonding in the rice straw, which can be improved by chemical treatment. Therefore, the objective of this study was to investigate the effect of chemical processing (with nitric acid, sodium hydroxide, and sodium hypochlorite) as a desilication method on the chemical composition, fermentation parameters, and in vitro digestibility of nutrients of rice straw and rice bran, and compare them wheat straw and bran.
Method: Rice straw and bran were desilicated using nitric acid, sodium hydroxide, and sodium hypochlorite, pressure, heating and drying. The experimental treatments included 1- Straws: 1- wheat straw as positive control, 2- untreated rice straw, 3-treated rice straw and 2- Brans: 1- wheat bran as positive control, 2- untreated rice bran and 3- treated rice bran). Chemical composition, concentration of silica, in vitro gas production parameters and neutral detergent fiber (NDF) digestibility of all treatments were measured and metabolizable energy (ME), organic matter digestibility (OMD) and short-chain fatty acids concentration were estimated.
Results: Chemical treatment significantly decreased (P<0.05) the contents of silica, crude protein, ether extract and ash in treated rice straw when compared with untreated rice straw. No significant effects were observed for potential of gas production, lag time, ammonia nitrogen concentration, total protozoa population, NDF, and acid detergent fiber; however, gas production rate and estimated short chain fatty acid (SCFA) concentration increased (P<0.05) and pH decreased (P<0.05) in treated rice straw compared to untreated rice straw and wheat straw. The in vitro NDF digestibility tended to increase in treated rice straw compared to untreated rice straw and wheat straw. Chemical processing reduced dry matter, crude protein, ether extract and ash contents, and increased pH (P<0.05). Gas production potential, gas production rate, ammonia nitrogen concentration and NDF decreased in treated rice bran compared to untreated rice bran (P<0.05). However, chemical treatment had no effect on lg time, total protozoa population, Epidinium and Entodinium population, estimated ME, OMD and SCFA concentration.
Conclusions: Chemical treatment increased the digestibility of fiber fraction of the rice by-products, reduced the anti-nutritional compounds (silica), and improved some fermentation and digestibility characteristics, and therefore makes them suitable for use in the diet of livestock.
کلیدواژهها English