There are eight common categories of aquatic feeds
At present, there are many kinds of feeds used for aquaculture, with different nutrient composition and nutritional value. In order to understand the characteristics of various feeds and to use them rationally, it is necessary to properly classify the feeds. Feed classification is to determine a standard for each feed, which can reflect the characteristics and nutritional value of the feed. The feed belonging to the same standard has basically the same characteristics, composition and nutritional value.
The principles of feed classification are simple, practical and scientific. From the perspective of aquaculture animal nutrition, feeds are divided into multivitamins feeds, protein-rich feeds, and feeds with more crude fiber and low energy value. There are three commonly used classification methods.
According to the International Feed Classification, feed ingredients can be divided into eight categories:
Roughage: The crude fiber accounts for more than 18% of the dry weight of the forage, such as hay and crop straw.
Green feed: green plants with natural moisture above 60%, leaves and non-starchy rhizomes, melons and fruits, regardless of the content of crude protein and crude fiber after drying.
Silage: silage prepared from fresh natural plant feed, silage with appropriate amount of bran or other additives, and low-moisture silage with a moisture content of 45% to 55%
Energy feed: feed dry matter crude protein less than 20%, crude fiber less than 18%, such as grains, bran, grass seeds, seeds and starchy rhizomes and fruits.
Protein feed: The crude protein in the dry matter of the feed is more than 20% and the crude fiber is less than 18%, such as animal feed, bean cake, meal and others
Inorganic salt feed: including industrially synthesized and natural single inorganic salt feed, multiple inorganic salts, mixed inorganic salt feed and inorganic salt additives as loadings or diluents
Vitamin feed: refers to the industrially synthesized or extracted single vitamin or multivitamin, but does not include natural feed containing a lot of certain vitamins.
Non-nutritive: all additives that do not include minerals, vitamins, amino acids and other nutrients, their function is not to provide nutrients for animals, but to help the digestion and absorption of nutrients, stimulate animal growth, protect feed quality, improve Substances responsible for feed utilization and aquatic product quality.
When choosing the feed, some nutrient-deficient feed varieties are accidentally selected, and supplements can be added at a later stage, such as navirin for vitamin supplementation.
What are the nutritional values of different feeds?
By nutritional value:
According to the approximate content of nutrients in the feed, the feed can be divided into 4 types: This classification method is mainly based on people's experience and is easy to remember. The disadvantage is that there is no nutrient content boundary for the division of various feeds, and the nutritional value of different feeds in the same type of feed is quite different.
1. Rough fodder Generally, the fodder with large volume, more crude fiber, less digestible components and low nutritional value is used as rough fodder. Such as straw, pod shell, hay and so on.
2. Green feed refers to green crops and vegetables with high natural water content.
3. Concentrated feed Compared with roughage, the small volume, low crude fiber content, and more digestible components are called concentrated feeds, such as grain seeds, legume seeds, cakes, bran and so on.
4. Additives that do not belong to the first three categories are classified into this category. Including various vitamin additives, mineral salts, yeast, growth hormone, etc.
By feed source:
According to the feed source, feed can be divided into animal feed, plant feed, microbial feed, mineral feed, and synthetic feed. The classification method is in line with people's general habits, and it is also convenient for organizing feed. But it does not reflect the internal characteristics of feed value.
Animal feed Animal feed comes from the processing of aquaculture animals, meat, poultry and dairy products, and is feed processed from animal products, such as fish meal, meat meal, meat and bone meal, feather meal, etc. The nutritional value of this type of feed is generally higher than that of plant-based feed. With the deepening of aquaculture animal nutrition research, animal feed is no longer an essential component of aquaculture animal feed, but compared with plant feed, animal feed still has great advantages. It is generally believed that the feed must include certain amount of animal feed. And some animal commercial feeds themselves are by-products, and full utilization can bring about greater benefits. Compared with plant-based feeds, animal-based feeds have the following characteristics:
1. The protein content is high, and the essential amino acids that are easily lacking in general plant feeds are more abundant in animal feeds, and the biological value of protein is high. The content is 40 to 90%, and most of them are above 50%.
2. Low carbohydrate content. Does not contain crude fiber, high digestibility and utilization.
3. The mineral elements are rich, the proportion is balanced, and the utilization rate is high.
4. Rich in vitamins, especially high content of B12.
Plant-based feeds, such as cereal seeds, green feeds, cakes, etc., are feeds with rich sources and high dosages, and are an important part of aquaculture animal feeds, usually accounting for more than 50% of the feed formula. Grain seeds are usually called "seeds", and this type of feed basically belongs to the mature seeds of grasses. Common types include corn, wheat, rice, barley, etc. The crude fiber content is low, with an average of 2 to 6%. The digestibility and utilization rate of cereal seeds is high, and the available energy value is high. This is the outstanding feature of grain feed.
All kinds of cereal seeds can be divided into seed coat, endosperm and embryo from outside to inside. The functions of various tissues are different, and the nutrients contained in them are very different.
Seed coat To protect the tissue, it is high in crude fiber and rich in vitamins and minerals. Most of the crude fiber of the seed is concentrated in the seed coat.
The endosperm is the storage organ of nutrients, mainly contains starch, and also contains some monosaccharides and disaccharides, and the protein content is low, mainly gliadin. Endosperm is divided into horny endosperm and silty endosperm. The former has dense and transparent tissue, high protein content and relatively high relative density; the latter has a loose tissue with voids between starch granules, white and opaque, low protein content and low relative density.
The embryo is an important part of the seed, the original body of the new individual of the plant, that is, the growth tissue. It contains more fat, which can be as high as 30% or more. Protein rich. It is also higher in minerals and vitamins (especially B vitamins). The embryo accounts for about 3 to 5% of the seed.
Different grains have different nutritional values due to different compositions. The protein content is about 7-13%, the content is low, and the quality is poor. Compared with its energy value, it is lower, and it is difficult to meet the protein requirements of aquaculture animals. However, since this type of feed occupies a large proportion in the full-price compound feed, its protein content and quality have a great influence on the quantity and quality of the protein in the full-price feed. Grain protein content varies by cultivar and climatic conditions. When the protein increases, the relative proportion of various proteins also increases. The biological value of cereal protein is only 50-70%, and the limiting amino acids are almost all lysine. The mineral content is unbalanced. The calcium content is generally lower than 0.1%, while the phosphorus content is as high as 0.3 to 0.5%, but it is mainly phytate phosphorus, which has a low utilization rate and can interfere with the utilization of other mineral elements. The vitamin content is unbalanced, generally containing vitamin B1, rich in niacin and vitamin E, but lacking in vitamin B2, vitamin D and vitamin A.
Microbial feed The feed produced by the use of microorganisms including drunken mother, mold, bacteria (such as Bacillus in aerobic) and algae.
Mineral feeds include natural and industrially produced minerals, such as stone powder, table salt, copper sulfate, etc., which can supplement the needs of aquaculture animals for minerals.
Synthetic feed is the feed produced by microbial fermentation, chemical synthesis and other methods, such as synthetic amino acids, urea, vitamins, antibiotics, etc. Formulated feed based on effective amino acids can give full play to the feeding value of cottonseed meal. After adding synthetic lysine, threonine and tryptophan, fish meal can be completely eliminated, and the dosage of soybean meal can be reduced: cotton and rapeseed meal alone or in combination can replace the protein of soybean cake in feed by less than 50%.
There are eight common categories of aquatic feed, and what are the nutritional values of different feeds? That's all for you here, I hope it helps! In the feed, adding an appropriate amount of sodium bicarbonate every day can significantly improve the effective utilization rate of the feed, and the daily weight gain is significantly increased, thereby reducing the feeding cost and significantly improving the economic benefits of raising livestock.