How to detect non protein nitrogen in feed ingredients

There are two main methods for detecting non-protein nitrogen in feed raw materials:

1.Copper sulfate precipitation method: according to the chemical properties of non-protein nitrogen, most of it is soluble in water, and some of it is insoluble at room temperature, but it is dissolved in boiling water.

The sample is first boiled and the proteins in the sample are precipitated with copper sulfate, and since the non-protein nitrogen is already soluble in water, it can be separated from the protein in the sample by filtration. When filtering, the temperature of the water must not be too low, otherwise substances such as biuret will not be filtered out because they are insoluble in room temperature water. The protein content determined by this method is called the true protein of the sample.

In practice, however, this approach has significant limitations. If non-protein nitrogen is insoluble in boiling water, or if generic non-protein nitrogen is microencapsulated, the results measured by this method can be very different from the actual true protein in the sample.

2.Detection of urea in urine: take about 5g of the sample, put it on a clean filter paper, then add about 5g of raw soybean powder, stir well, moisten it with distilled water, drop in a few drops of cresol red reagent, let it react for 3 5min, if there is urea, it will be red, and spread out like a spider's web, and no urea will show yellow.

Please note that the above methods are only for the initial detection of non-protein nitrogen, and if more precise test results are required, it is recommended to send them to a specialized laboratory for testing.

True protein determination method 1, principle Copper sulfate in alkaline solution, protein can be precipitated, and insoluble in hot water filtration and washing, pure protein and non-protein egg-containing can be separated, and then the protein content in the precipitate can be determined by Kjeldahl egg method. 2. Instruments and equipment (1) Beaker.

200ml。(2) Qualitative filter paper. (3) Other equipment is the same as that of crude protein assay. 3. Reagents and preparation (1) 100g L copper sulfate solution.

Analysis of pure copper sulfate (CuSO4·5H2O) 10g dissolved in 100ml distilled water.

Middle. (2) 25g l sodium hydroxide.

Solution: Dissolve analytical pure sodium hydroxide in 100 ml of distilled water. (3) 10 g l barium chloride.

Solution: 1g of barium chloride (BACL·H2O) dissolved in 100ml of distilled water. (4) 2mol hydrochloric acid solution.

5) Other reagents are the same as those of the general crude protein assay. 4. Determination steps Accurately weigh about 1g of the sample (accurately, put it in a 200ml beaker, add 50ml of distilled water, heat to boil, add 20ml of copper sulfate solution, 20ml of sodium hydroxide solution (add the above two solutions more slowly, and stir while adding), fully stir with a glass rod, place it for more than 1h, filter it with an inclined (with shaped filter paper), and then wash the precipitation with 60 80 hot distilled water 5 6 times, check the filtrate with 5 drops of barium chloride solution and 1 drop of hydrochloric acid solution, until no white precipitate is generated. The pellet and filter paper were dried in a 65 oven for 2 h, and then all transferred to Kjeldahl flasks, digested and then subjected to egg fixing.

5. The result calculation is the same as that of crude protein determination.

Quantitative testing requires very high equipment, I don't know if you have noticed!

Summary. Nitrogen analyzers are commonly used to detect protein content. In addition, the total nitrogen content in the soil can also be analyzed by a nitrogen analyzer.

Nitrogen analyzers are commonly used to detect protein content. In addition, the total nitrogen content in the soil can also be analyzed by a nitrogen analyzer.

All are determined using the same method.

What is the reason for the high organic matter content measured by potassium dichromate external heating method?

What is the reason for the high organic matter content measured by potassium dichromate external heating method?

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1) When using non-protein nitrogen, there should be a certain amount of soluble carbohydrates in the diet, the crude fiber content should not be too high, and the natural protein content should be 10%-12%.

2) The content of non-protein nitrogen should be controlled within 1% of the feed weight, otherwise the non-protein nitrogen will be decomposed too quickly and cause cattle poisoning. Poisoning is found to be administered with 2% to 5% acetic acid.

3) When mixed with soybean cake and other feeds with high protein content, urease inhibitors should be added.

4) Do not drink water within 30 minutes of feeding non-protein nitrogen feed, and do not dissolve non-protein nitrogen directly in water**, so as not to directly enter the real stomach and cause poisoning.

5) The amount of urea can account for 1 3 of the total protein of the diet, and each cow should not exceed 90g per day, and urea should be mixed into the concentrate, and it is necessary to pay attention to supplementing sulfur at the same time, so that the nitrogen-sulfur ratio reaches 15:1.

6) Pay attention to vitamin A supplementation and add table salt to the diet.

7) The feeding method is from less to more, step by step, and it generally takes a transition period of 5-10 days to gradually reach the specified amount.

Non-protein nitrogen is a general term for a class of non-protein nitrogen-containing compounds, and the non-protein nitrogen used in dairy cow production mainly includes urea, biuret, ammonium salt, etc. (Liu Defang, 1993).

After the feed protein enters the rumen, it is first degraded into peptides and amino acids by rumen microorganisms, and most amino acids are further degraded into organic acids, ammonia and carbon dioxide. Ammonia and some simple peptides and free amino acids produced by microbial degradation are used to synthesize microbial proteins into the stomach and small intestine to be digested and utilized, and the excess ammonia accumulates in the rumen and exceeds the maximum ammonia concentration that can be used by rumen microorganisms, at this time, the excess ammonia is absorbed by the rumen wall, and is converted into urea through the portal vein with the blood into the liver, and the urea produced is absolutely like a part of the urea returned to the rumen through saliva and blood to be used again, but most of it is wasted with the discharge of urine. This ammonia is produced and continuously recycled with urea, known as rumen and urea recirculation (Yang Feng, 1993;Hao Zhengli et al., Rubber Stool 2000).

Due to this special cycling, non-protein nitrogen is added to the cow feed as a feed for microbial synthesis of protein.

In addition to protein or peptides, nitrogen-containing forms of feed, called non-protein nitrogen feed, microorganisms in the rumen of sheep can degrade the protein in the feed to synthesize microbial protein and non-protein nitrogen sources, both of which are precursors of amino acids, microorganisms can use it to synthesize microbial proteins, through digestion, microorganisms pass from the rumen to the digestive organs farther away. In the true stomach and small intestine, these microorganisms are broken down into free amino acids by the action of digestive enzymes and digestive juices in the digestive tract, and finally absorbed by the intestines. Through the action of microorganisms, the utilization process of non-protein nitrogen-bacterial protein-amino acid-intestinal absorption was realized, so as to improve the feed value of non-protein nitrogen and reduce the feed cost.

The most commonly used non-protein nitrogen is urea, which contains about 46% nitrogen, white particles, and is slightly soluble in water. 1 gram of urea is equivalent to a gram of protein, or 1 kilogram of urea plus 6 kilograms of corn is equivalent to 7 kilograms of soybean cake. Urea feeding amount:

13 18 g per day for adult sheep and 8 12 g per day for young sheep over 6 months of age, with urea in the diet not exceeding 1 per cent of other dry matter.

There are several feeding methods for urea: Feed directly into the feed: evenly mix urea into the mixed feed containing grain concentrate and protein concentrate and feed; Add to the silage:

At the same time as feeding silage, it is added according to the wet weight of silage; Mixed feeding with green hay: under the condition of house feeding, the urea solution is sprayed on the crushed green hay for feeding; Make urea concentrate bricks for licking (Figure 7-1).

Figure 7-1 Application method of non-protein nitrogen-containing substances (a transition period must be set).

a) When the crude protein content in the diet is less than 12%, non-protein nitrogenous substances can be added (b) Crushed concentrate and urea can be added (c) Use method 1Mix directly into concentrate 2Make an aqueous solution, spray on the concentrate, and stir into a ball 3

Made into pellet feed 4Made of licking bricks (no picture).

1 What is a non-protein nitrogen feed.

All nitrogen-containing non-protein substances that can be used as feed can be called non-protein nitrogen feed. Non-protein nitrogen refers to non-protein nitrogen-containing substances, and more than 20 kinds of non-protein nitrogen have been used in ruminant feed experiments, and the better effect is urea and biurea.

2 Utilization of non-protein nitrogen feeds.

The nitrogen content of urea in non-protein nitrogen feed is 46%, which is a commonly used substitute for ruminant protein feed because of its wide range, easy transportation and preservation. However, it must be noted that the purpose of feeding beef cattle with urea is to conserve protein feed. If the protein feed is wide and low, it is not necessary to feed urea at all, but should be fed with protein feed.

This is because urea does not provide any nutrients other than nitrogen. Attention should be paid to feeding cattle with urea (or under the guidance of a technician): 50 100 grams of urea per day per fattening cow; Cattle are easy to eat after mixing with concentrate feed; The cow can not be given water within 2 hours after feeding urea, and can only be drunk after 2 hours; Before feeding cattle with urea, the antidote in case of poisoning should be prepared, or the vinegar should be given in time, or the acetic acid solution should be given in 2%.

Beware of counterfeit products when buying. Calves cannot be fed with urea.