With the widespread use of feed enzyme preparations in feed, more and more enzyme preparation products have emerged on the market. How to choose the appropriate enzyme preparation products has always been a problem that plagues users. By analyzing the enzyme preparation in vitro, the quality of the enzyme can be assessed to a certain extent, and its effect in the animal body is predicted. In this paper, the activity determination and temperature resistance evaluation of feed enzyme preparations are expounded, in order to provide reference for users to scientifically and rationally select enzyme preparation products.
1. Detection of the activity of feed enzyme preparations
The determination of enzyme activity is essential in the quality inspection of feed enzyme preparation products, product labeling and enzyme activity assurance. Enzyme activity is the primary indicator for evaluating the performance of feed enzyme preparation products. Temperature, pH, reaction time and substrate are the most important defining factors in the determination of enzyme activity; while the dilution of enzyme solution, standard curve, color reagent, and ionic strength of buffer solution are non-definitions that affect the determination of enzyme activity. Elements. In addition, the determination of enzyme activity will be affected by some details, such as details of operation, centrifugation speed, shaking force and frequency, extraction time, proper use of pipettes, and cleanliness of glassware. Especially in the detection of some unstable enzyme preparations, the negligence of these details will often have a greater impact on the results. Since the determination steps of the viability of most feed enzyme preparations are complicated, especially for enzyme preparations (such as mannanase, etc.) that have not yet established national or industry standards, the definition and determination of enzyme activity by various manufacturers The method, substrate and reaction conditions are not uniform, which makes the same product produced by different enterprises lack comparability. The enzyme activity of the same product is very different, which causes many inconveniences for users to purchase and use. It is difficult to objectively evaluate the product. Bad.
In addition, the manufacturer's self-defined corporate standards, standard health indicators are more confusing, some projects are not included in some enterprises, and some project indicators are low. Therefore, for feed manufacturers, the enzyme activity detection method and related indicators should be requested from the enzyme preparation manufacturer. In the process of detecting the activity of the feed enzyme preparation, not only the main factors affecting the activity determination of the enzyme preparation should be noted, but also the influencing factors should be correctly grasped. The key points, for some other small influencing factors should also be concerned, try to make every point and step in the enzyme preparation test process, when comparing the activity of the same enzyme granule from different manufacturers, it should be defined In the same situation.
2. Evaluation of temperature resistance of feed enzyme preparations
High temperature resistance is a bottleneck factor limiting the application of enzyme preparations in feed. At present, most of the broiler materials and some pigs in China use granulation technology. The granulation temperature is between 75 and 85 ° C and partly above 85 ° C. The damp heat method and the water bath method are commonly used methods for evaluating the thermal stability of enzyme preparations in the laboratory. The water bath method has certain advantages in evaluating the heat resistance of a naked enzyme (such as a fermentation broth or a high-purity enzyme product) produced by fermentation of a strain, and is not particularly suitable for a finished product of a post-processed or coated enzyme preparation. In addition, the dilution concentration of the enzyme solution selected in the water bath method, the bath temperature, the treatment time, and the depth of the enzyme solution inserted into the water surface have a great influence on the experimental results. The damp heat method is based on the simulation process and processing parameters of the simulated feed granulation, and a certain temperature, humidity and time gradient are set to evaluate the enzyme activity of the enzyme preparation after treatment. Therefore, the method is closer to the water bath method. It is the real process of feed granulation, and is also more suitable for the heat resistance evaluation of the finished enzyme preparation. Especially for a wide range of solid enzyme preparations, the damp heat method can evaluate its heat resistance more simply, quickly and accurately.
In addition to the above two laboratory evaluation methods, the on-site granulation test is the most effective one to evaluate the temperature resistance of the feed enzyme preparation. Due to the different feed mills, the feed formula, the dosage of the added enzyme preparation, the granulation processing parameters, the granulating equipment and the sampling means are quite different, and there is no real effective method for detecting the activity of the enzyme preparation in the feed. Therefore, it is difficult to ensure the repeatability, effectiveness and accuracy of the evaluation of the heat resistance of the enzyme preparation product by the granulation test. When conducting on-site granulation tests, the timing of sample collection is critical, so strict procedures should be followed to ensure success.
The recommended procedures are:
(1) remove any other enzymes having the same functional activity as the enzyme preparation to be tested from the formulation;
(2) Add the enzyme preparation to be tested to each mixed batch of feed at a suitable dose. Ideally, five batches should be used for each test, especially when the feed mill is using a similar product;
(3) Extract at least five samples (powder) from each batch of feed containing test enzymes;
(4) When the relevant mixed batch of feed leaves the granulator and cooling tower, it should be inspected together with the staff of the feed mill. Their knowledge of capacity (tons of feed produced per hour) will help to make judgments;
(5) When the pellet feed mill reaches its operating capacity and steam heat target (shown on the computer), record the pellet outlet temperature of the pelletizer with a digital temperature detector connected to a vacuum flask or thermos;
(6) Immediately sample the pelletized and cooled pellets from the appropriate location of the cooling tower. When the mixed batch of feed to be sampled is discharged at the cooling tower, it is best to confirm with the employee and sample continuously. , every 20 to 30 s to ensure the representativeness of the collected samples;
(7) All samples (particles and powders) were analyzed using appropriate analytical methods to calculate average enzyme activity and uniformity (coefficient of variation). The above process only evaluates the same enzyme preparation product of different manufacturers based on the same feed mill and the precise control of processing conditions.
In addition, in the granulation test, the uniformity of the distribution of the enzyme preparation in the feed should be ensured first, and the collection of the second sample is also crucial. For the analysis of the enzyme activity in the feed sample, different added enzymes may have different samples. Qualitative problem. Due to sampling range and cost issues, it is difficult to take practical measures to ensure that samples representative of the laboratory are available. It is generally considered to increase the sampling point and take 200-400 g samples at each sampling point. After the completion of the on-site granulation experiment, the processing and analysis of the collected samples is also particularly important for evaluating the temperature resistance of the enzyme preparation. Samples are typically cryogenically pulverized, mixed, and subsampled in the laboratory prior to actual testing. After the subsampling, a preliminary analysis of the sample can be performed on the sample. Effective enzyme activity must be extracted from the feed prior to enzyme activity analysis. Regardless of whether the sample is comminuted, it is impossible to analyze the enzyme activity in the dry sample. A common means of extracting effective enzyme activity from feed is liquid phase extraction, in which a specific buffer is added to the feed sample and the enzyme is dissolved in the buffer after shaking for a period of time. Incomplete extraction of this process will result in loss of enzyme activity, or the incomplete dissolution of the enzyme will result in lower enzyme activity, which will directly affect the retention of enzyme activity. Therefore, this process requires strict control of extraction conditions (such as oscillation strength, time, composition of the extract, and pH).
In addition, most of the current enzyme preparation methods are only for the determination of the viability of the product itself, and do not include the detection of enzyme activity in the feed. Therefore, we also need to constantly explore and study effective methods for sensitive detection of the activity of the enzyme preparation in the feed.
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