What is crude fiber Crude fiber includes not only cellulose and residual hemicellulose, but also lignin, keratin and other ingredients. This type of substance is generally not dissolved by dilute acid or dilute alkali, nor is it digested and absorbed by humans or livestock and other organisms. Therefore, the crude fiber in the conventional feed is prepared by boiling the feed sample with 1.25% dilute acid and dilute alkali and then measuring the remaining mass. However, this method is inaccurate, and the result is often low, because organic substances such as lignin in crude fiber are partially dissolved in acid and alkali. Crude fiber was once abandoned due to its inability to be absorbed by the body. However, later, people found that the consumption of crude fiber can effectively prevent some diseases or reduce the incidence of diseases. For this reason, crude fiber was taken seriously by people and it was renamed dietary fiber. Crude fiber food Crude fiber food refers to foods containing more than 2 grams of crude fiber per 100 grams of food, mainly food, vegetables, fruits, and beans. At the same time, crude fiber can be divided into soluble dietary fiber and insoluble dietary fiber. The former is mainly found in fruits and beans, while the latter is mainly found in coarse grains and coarse grains. Crude fiber foods have a relatively high stomach requirement and require a high digestive capacity of the stomach. At the same time, excessive consumption of crude fiber will affect the absorption of other essential elements. Feed coarse fiber determination method 1 Scope of application This standard specifies the method for the determination of crude fiber content in feeds. Suitable for all kinds of mixed feed, compound feed, concentrated feed and single feed. 2 Reference standards Preparation of Standard Solution for GB/T 601 Chemical Titration Analysis (Capacity Analysis) 3 Principle The sample is decontaminated with an accurate concentration of acids and bases under specific conditions, and then the soluble matter is removed with ethanol. The amount of minerals deducted by high-temperature ignition is the crude fiber. It is not an exact chemical entity, but The schematic components measured under generally recognized mandatory conditions are mainly cellulose, with a small amount of hemicellulose and lignin. 4 Reagents The reagents used in this method were analytically pure and distilled water. The standard solution was prepared according to GB601. 4.1 Sulfuric acid (GB 625) solution 0.128±0.005mol/L: Sodium hydroxide standard solution calibration, GB 601. 4.2 Sodium hydroxide (GB 629) solution, 0.313 ± 0.005 mol/L: Potassium hydrogen phthalate calibration GB 601. 4.3 Pickling asbestos HG 3-1062. 4.4 95% Ethanol (GB 679). 4.5 Ether (HG 3-1002). 4.6 n-octanol (antifoaming agent). 5 Equipment 5.1 Sample mills for laboratories. 5.2 Sample Screen: Aperture 1mm (18 mesh). 5.3 Analytical balance: Sensitivity 0.0001g. 5.4 Electric heater (electric furnace), adjustable temperature. 5.5 Electric thermostatic oven (oven): The temperature can be controlled at 130 °C. 5.6 high temperature furnace: a pyrometer can control the temperature in the 500 °C ~ 600 °C. 5.7 Cooker: A 600-mL high beaker with a condensing ball or an Erlenmeyer flask with a condensate tube. 5.8 suction filter device: vacuum device, suction filter flask and funnel. (The filter uses 200 mesh stainless steel mesh or nylon filter cloth). 5.9 Gu's cockroach: 30mL, pre-adding 30mL of acid-washed asbestos suspension (containing 0.2 to 0.3g of acid-washed asbestos) and then withdraw to make the thickness of asbestos uniform and opaque. Two layers of glass fibres help to filter. 5.10 Desiccator, with calcium chloride or discoloration silica gel as a desiccant. 5.11 Crude fiber measuring instruments: Instruments produced at home and abroad that conform to the principle of measurement of this standard and have consistent measurement results. 6 sample preparation The sample was reduced to 200 g by quartering, crushed, all passed through a 1 mm sieve, and placed in a sealed container. 7 Analysis steps 7.1 Arbitration Act Weigh 1 ~ 2g sample, accurate to 0.0002g, degreasing with ether, (with fat greater than 10% must be defatted, containing fat is less than 10%, can not degrease), into the digester (5.7), plus the concentration is accurate and 200 mL of boiled sulfuric acid solution (4.1) and 1 drop of n-octanol were heated immediately. They should be boiled within 2 min. The heater was adjusted to keep the solution slightly boiled and continuously micro-boiled for 30 min, keeping the concentration of sulfuric acid unchanged. The sample should not leave the solution and stick to the wall of the bottle. After suction filtration, the residue was washed with boiling distilled water until neutral and then dried. The residue was transferred to the original container with an accurately concentrated and boiled sodium hydroxide solution (4.2) and added to 200 mL. Similarly, the mixture was micro-boiling for 30 min. Immediately, it was filtered on Aspergillus glaucoides and washed with 25 mL of sulfuric acid solution. The residue was transferred without loss to cesium (5.9), washed with boiling distilled water to neutrality, washed with 15 mL of ethanol (4.4), and dried. The enthalpy (5.9) was placed in an oven (5.5) and dried at 130±2°C for 2 hours. After being taken out, it was cooled to room temperature in a desiccator (5.10), weighed, and then heated in a 550±25°C oven (5.6). Burn for 30 minutes, remove and cool in a desiccator (5.10) to room temperature and weigh. 7.2 Recommended Practice Weigh 1~2g of sample (degreasing step is the same as manual method) in G2 glass sand funnel, insert the funnel into the hot extractor with clips; add 200mL of pre-boiled sulfuric acid solution and two drops of n-octanol from the top, and heat the knob Open to the maximum position. After the solution is boiled, turn the knob to a suitable position to keep the solution slightly boiled for 30 min, suction filter, wash with boiling distilled water to neutrality, add 200 mL of pre-boiled sodium hydroxide solution, the same accurate micro-boiling 30min, suction filtration, washed with boiling distilled water to neutrality, transfer the hydrazine (5.9) to a cold extractor, add 25mL of 95% ethanol, suck dry, transfer the funnel to the oven (5.5), drying at 130±2°C for 2h After taking out, it is cooled to room temperature in a desiccator (5.10) and weighed. Then put it in a 500±25°C high-temperature furnace (5.6) for 1 h, and then cool in a desiccator (5.10) to room temperature and weigh it. Refer to the instruction manual of the instrument for the specific operation procedures of different models. 8 Calculation of measurement results 8.1 Calculation Formula Crude fiber (%) = (m1-m2)/m Where: m1 ─ ─ 130 °C after drying å©åŸš and the sample residue weight, g; m2 ─ ─ 550 °C (or 500 °C) after burning and the sample residue weight, g; m ─ ─ sample (not defatted ) Quality, g. 8.2 Repeatability Two parallel samples were taken for each sample and the arithmetic average was used as a result. The crude fiber content is below 10%, and the absolute value is a difference of 0.4. Crude fiber content is above 10% with a relative deviation of 4%. The rapid growth of animal husbandry and rapid population growth have led to the struggle between human and animal food. Although grain production is increasing every year, it still cannot catch up with population growth. Coupled with the rapid development of animal husbandry, the effective outlet for the feed industry has always been the focus of research. On the one hand, we must increase the utilization of feed. On the other hand, we must develop and produce new feeds. At present, new non-conventional feeds such as high fiber content have been highly valued by various parties and will be used in the production of feeds. The above table lists the content of various components of several animal feeds. Among them, the crude fiber we focus on in this article also includes it. From the table, we can see that hay and alfalfa hay contain higher crude fiber than sunflower meal and sunflower leaf meal. Of course, the content of crude fiber in some other feeds can be checked by oneself and will not be repeated here. 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