| Abstrakt: |
Introduction: The nutritional value of many lignocellulosic food materials can be improved by deligninating with physical, chemical and biological methods. Biological, chemical and physical methods are used to process agricultural by-products. In chemical processing, the use of acids, oxidative agents and alkalis are included, which alkalis are more accepted by animals in the animal husbandry industry. Biological processing is a new method that is done using enzymes and fungi. In the case of biological method, low-quality wood materials are processed by different species of fungi that have lignin-decomposing enzymes. Biological processing is an effort to use less chemicals and consume less energy compared to chemical and physical methods. Quinoa plant is a plant with good resistance to unfavorable environmental conditions, which has high tolerance against biotic and abiotic stresses. The cultivated area of the country is about 18.8 million hectares, and on the other hand, about a third of these lands are susceptible to cultivation due to poor quality soil and inappropriate water distribution, including salinity and drought. In areas with dry and salty conditions, using plants resistant to these conditions is a suitable way to deal with these conditions. So, a study was carried out to investigate the effect of different treatment methods (chemical and biological) on chemical composition, gas production parameters and digestibility of quinoa straw in a completely randomized design. Materials and methods: The following treatments were: 1) untreated quinoa straw (control) (CON), 2) CON processed with hydrogen peroxide, 3) CON processed with sodium hydroxide, 4) CON inoculated and fermented with Bacillus Subtilis and 5) CON inoculated and fermented with Aspergillus Niger. Prior to hydrogen peroxide treatment (132 mL of 35% H2O2), samples were pretreated with sodium hydroxide (NaOH, 80 g/kg DM) to attain and maintain a pH of 11.5. For biological processing, activation of lyophilized vials and preparation of starter cultures of bacteria and fungi were done in MRS-broth at 37°C and PDA at 25°C, respectively. After that, one liter of the combination of distilled water and starter culture (containing at least 105 colony forming units per milliliter of bacteria or fungi) was added to each kilogram of quinoa straw.Treated samples were then placed into plastic bags, tied up and stored under anaerobic conditions. Prior to analysis, bags were opened and air dried. Chemical composition of the samples was determined using the standard methods of AOAC. Ruminal degradability trial was carried out using the nylon bag technique. Gas production test was used to estimate gas production parameters. In vitro digestibility of the samples was determined through the batch culture method. Results: The results showed that there was a significant difference between treatments in terms of chemical composition (dry matter, ash, organic matter and crude protein) (P<0.05). In this respect, the highest amount of dry matter was in the control treatment and the lowest in the hydrogen peroxide treatment. Among the chemical treatments, the treatments with sodium hydroxide had the highest and the treatments with hydrogen peroxide had the lowest values of Crude Ash. Different treatment methods had significant effect on gas production potential and rate (P<0.05). Treatments with control and fungi had the highest and sodium hydroxide treatment had the lowest gas production potential. Treatment with sodium hydroxide and hydrogen peroxide significantly increased dry matter and organic matter digestibility (P<0.05). In general, the bacteria had the lowest digestibility, partitioning factor, and microbial protein production. Conclusions: Overall, the results of this study showed that treatment with sodium hydroxide and hydrogen peroxide had a greater effect on improving the nutritional value of quinoa straw. [ABSTRACT FROM AUTHOR] |
