How to control the risk of excessive trace elements after the "2625" announcement

It is well known that long-term use of inorganic trace elements has caused serious pollution to the environment. The regulatory authorities are also well aware of the current pollution status of trace elements in China's water and soil. In order to develop new agriculture in the “green water and green hills”, the Ministry of Agriculture announced the announcement of the 2625 on December 15, 2017. The core of the announcement is to limit the amount of zinc oxide and limit the maximum amount of major trace elements such as copper, iron, zinc and manganese in the feed. It is clearly stated in the announcement that the maximum amount is calculated as 88% dry matter content and contains the feed material background value. Then how many trace elements are contributed in the feed background, and how to choose and use trace element additives? 36K China Feed Industry Information Network - based on feed, serving animal husbandry

1 main feed ingredients trace element content 36K China feed industry information network - based on feed, service animal husbandry

Natural feed ingredients contain certain trace elements. The following table reports Ewan's determination of trace elements in corn and soybean meal. The data in the table shows that the trace elements in the feed background are greatly affected by the origin, geographical location and climate of the raw materials. The maximum and minimum values ​​monitored are several times different. From the average value combined with the limit standard, the zinc content of the feed ingredients is high, and a slight inadvertent result in excessive zinc content. 36K China Feed Industry Information Network - based on feed, serving animal husbandry

36K China Feed Industry Information Network - based on feed, serving animal husbandry

Recently, domestic research institutions have also tested and summarized the trace element content in raw materials, and the main trace element contents are listed in the following table. According to the limit standard of the full-price trace elements in the growing fattening pigs, the raw materials and elements exceeding the standard have been marked as red, and the formulator should pay special attention to the use of these materials. 36K China Feed Industry Information Network - based on feed, serving animal husbandry

36K China Feed Industry Information Network - based on feed, serving animal husbandry

Note: The data comes from China Agricultural University and has not been published yet. 36K China Feed Industry Information Network - based on feed, serving animal husbandry

It can be seen that the risk of zinc exceeding the standard is high, especially when using rice by-products, sorghum, barley and DDGS, special attention should be paid to the risk of exceeding the standard. According to our test for some test feeds, the trace element copper content of pig feed is 7-15 ppm, iron 150-225 ppm, zinc 25-45 ppm (higher use of rice by-product or sorghum), manganese 17-43 ppm . 36K China Feed Industry Information Network - based on feed, serving animal husbandry

2How to add trace elements under the new standard 36K China Feed Industry Information Network - Based on feed, serving animal husbandry

The feed background contains certain trace elements, but these trace elements form complexes with molecules such as phytic acid, making it difficult for animals to use. To ensure animal growth performance, reproductive performance and immune function, dietitians must also supplement trace elements. The following table uses the limited standard for growing fattening pigs as an example to analyze the level of addition of major trace elements. 36K China Feed Industry Information Network - based on feed, serving animal husbandry

36K China Feed Industry Information Network - based on feed, serving animal husbandry

As can be seen from the table, the biggest challenge in terms of the risk of trace elements exceeding the standard is copper and zinc. The addition of copper is only 10-18 ppm, which can not meet the requirements of farmers for blackening of feces. This also requires the feed enterprises to guide the farmers. How does the addition of 35 ppm zinc ensure the immune function of growing animals? In addition, it is estimated that only 60-75 ppm zinc can be added to the breeding pigs. In this case, organic trace elements are the best choice for the feed and aquaculture industry. 36K China Feed Industry Information Network - based on feed, serving animal husbandry

3 How to choose organic trace elements 36K China feed industry information network - based on feed, service animal husbandry

At present, there are many kinds of organic trace elements in the market, including amino acid chelates, complexes, protein salts, polysaccharide salts and organic acids. The price ranges from a few dollars to tens of dollars. What is the difference between them? The element is in the form of metal ions in the digestive tract. It is easy to form precipitates in the alkaline environment of the intestine, and the charged ions are not easily absorbed and there is antagonism between different element ions, so the utilization rate of inorganic trace elements is extremely low. Most of the organic trace elements are complexes or chelates. The chemist balance constant is used to measure the stability of various complexes, ie, the formula is 36K China Feed Industry Information Network - based on feed, serving animal husbandry

36K China Feed Industry Information Network - based on feed, serving animal husbandry

Where [ML] indicates the concentration of the complex (鳌), [M] indicates the concentration of the free metal ion, and [L] indicates the concentration of the free ligand. Generally, the larger the equilibrium constant, the more stable the complex, and the smaller the equilibrium constant. The more easily the complex is dissociated, the stability of the complex (chelate) can be expressed by its equilibrium constant. Taking copper as an example, the stability constants of various (complex) chelate compounds are listed in the following table. 36K China Feed Industry Information Network - based on feed, serving animal husbandry

36K China Feed Industry Information Network - based on feed, serving animal husbandry

It can be seen from the table that the larger the equilibrium constant is, the more stable the complex is, and the higher the proportion of trace elements present in the complex state. 36K China Feed Industry Information Network - based on feed, serving animal husbandry

The complex (鳌) conjugated trace elements can be directly utilized by the animal through the amino acid or small peptide absorption channels, and thus the titer of the organic (tegative) organic trace elements is higher. Once the chelating state is dissociated into an ionic state, it is essentially the same as the inorganic trace element. In general, the stability of specific small peptide complexes is higher than that of single amino acids (but this is not absolute), and a large number of literatures have confirmed that small peptide trace element complexes (protein salts) are currently Use the most efficient organic trace elements. 36K China Feed Industry Information Network - based on feed, serving animal husbandry