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Introduction to the technology of using phytase in laying hen feed

View: 20 Author: Site Editor Publish Time: 2023-03-22 Origin: site

Introduction to the technology of using phytase in laying hen feed

In addition to reducing the utilization rate of phosphorus, the anti-nutritional effect of phytic acid is also manifested in: ① chelating with some cations, such as Ca2+, Mg2+, Zn2+, Cu2+, Mn2+, Fe2+, to form insoluble phytate; ② phytic acid The phosphate group in the molecule combines with cationic groups such as protein, free amino acid, starch and fat in the feed to reduce its solubility; ③ Phytic acid can also combine with digestive enzymes in the body, such as amylase, protease, lipase, Reduce the enzyme activity of these enzymes.

Since monogastric animals basically do not secrete phytase, the utilization rate of phytate phosphorus is very low, generally not exceeding 30%, so adding exogenous phytase is an inevitable trend. The benefits of adding phytase  can be summarized as follows: ① Improve the utilization rate of phosphorus; ② Improve the digestibility of organic matter and mineral elements; ③ Save formula space and improve feed quality; ④ Improve animal production performance; ⑤ Reduce pollution of phosphorus sources; ⑥Reduce the acidity of the feed.

The effect of using phytase  in laying hen feed to reduce feed cost is the most obvious, but at the same time the reaction in production is also the most sensitive, especially in summer and peak egg production. Therefore, the use of phytase in laying hen feed must consider the egg production period, season and feed intake. In production, it is also reflected that the eggshell color of laying hens is whitish and the legs of laying hens are soft after using phytase. Some of these phenomena are related to the use of phytase, while some have nothing to do with phytase.

1. How Phosphorus Levels Are Adjusted Using Phytase

The substrate of phytase is phytate phosphorus, and the content of phytate phosphorus in general laying hen feed is 0.25% to 0.35%, which can fully meet the requirements of phytase hydrolysis. A common feature of the summer and peak laying seasons is low feed intake for layers, which results in insufficient nutrient intake, which can lead to lower laying rates, soft legs, and even changes in eggshell color. On the surface it is caused by the use of phytase, but in fact it is caused by a combination of factors.

The total phosphorus level of phytase used in summer and peak laying period should be at least 0.45%, and the total phosphorus level in winter and late laying period should be 0.40% to 0.42%. Of course, this is related to feed intake. Daily intake of 110g, total phosphorus level is 0.40%-0.42%; daily intake of 120g, total phosphorus level is 0.38%-0.40%. The appropriate ratio of phytase to replace calcium hydrogen phosphate in summer and the peak egg production period is 50% to 60%, or 7 to 8kg per ton of feed. Other seasons or other stages can replace 60% to 75%, or 8.5 to 10kg per ton of feed.

2. Formulation design and key points of processing

The potential nutritional value of phytase may not be considered in the design of feed formulations during summer and peak egg production periods. If the potential nutritional value is considered, the nutritional level of the diet, especially energy, should be increased to make up for the lack of nutrient intake. The remaining formula space must not be filled with stone powder, so as to avoid the imbalance of calcium and phosphorus ratio, and do not add substances without nutritional value (such as zeolite powder, bentonite, etc.).

Because the amount of phytase added is small, the uniformity of mixing is particularly critical. It is very necessary to dilute the premix in 2 times according to 1:10. Suitable diluents are corn flour, tamponade and multidimensional etc.

The temperature is high in summer, so try to store phytase in a cool and ventilated place to avoid moisture. In case of continuous high temperature (over 30°C) or long storage period of feed, the amount of phytase added should be increased by 5% to 10%.

3. Problems with eggshell color and leg disease

Eggshell color is mainly related to breed, laying age, raw material quality, medication, fallopian tube health , disease and stress. Little to do with the use of phytase. If there is a problem with phytase, it should first reflect the decline in egg production, and then there may be brittle eggshells. The genetics of some modern breeds of laying hens become unstable, and the heritability of eggshell color reaches 0.4 to 0.6. After 50 weeks of age, the eggshell color gradually turns white. The hygienic indicators of raw materials are unqualified, especially the bacteria and histamine in fish meal, the silicate in stone powder, and the fluorine in calcium hydrogen phosphate exceed the standard, which will affect the color of eggshells. When laying hens were given furazolidone, olaquindox and sulfa drugs, the eggshell color was abnormal. Layer hens suffer from salpingitis, ovarian cysts, and abnormal eggshell color. Some potential infectious diseases, such as Newcastle disease, avian influenza, infectious bronchitis, egg drop syndrome, will make the eggshell color whitish. Various stress factors, such as high temperature, light, water deprivation, fright, can also make the eggshell color become abnormal. Measures should be taken to solve the above factors affecting the color of eggshells.

 most of the soft legs of laying hens appear in the late stage of laying eggs, which is also called fatigue in caged laying hens. The higher the production performance, the larger the proportion, generally 0.3% to 0.5%. This is an inevitable phenomenon that the calcium absorption rate of laying hens is poor and the calcium storage in the body is used. If the ratio of calcium to phosphorus is appropriate and the activity of phytase is guaranteed, there is no direct relationship between soft legs and phytase. Provide a high-quality calcium source (it is recommended to use stone powder and shell powder together), use separate calcium supplements, increase vitamin D, prolong the light time, and supplement electrolytic multivitamins in drinking water, all of which can alleviate the above symptoms.