Animal protein feed is an important component of livestock and poultry diet, which largely determines the cost, utilization rate and breeding efficiency of the diet. Farmers must fully understand its characteristics, grasp the use of methods and matters needing attention, in order to obtain the maximum economic benefits.

　　一、fish meal

　　Fish meal is the best protein feed for chickens and pigs. The crude protein content of imported fish meal is up to 60% and that of domestic fish meal is 35% ~ 55%. Amino acids such as methionine, lysine and tryptophan are abundant in fish meal, and there are also known and unknown growth factors such as nucleotides, active peptides and taurine that promote growth. Therefore, fish meal is commonly used in aquaculture to supplement protein and regulate the balance of dietary amino acids.

　　Although fishmeal has many advantages, it also has obvious disadvantages:

　　1. High prices. Fishmeal is sold at a high price, which directly affects the cost of the diet. From the economic point of view, the amount of fish meal should be strictly controlled, in the diet of broilers and layers with the amount of 2% ~ 5% is appropriate.

　　2. Easy to spontaneous combustion. In the process of oxidation, the fat in fish meal will release a lot of heat, while the phosphorus contained in it will release elemental phosphorus after chemical decomposition, elemental phosphorus ignition point is very low, so poor preservation is easy to occur spontaneous combustion phenomenon.

　　3. It's perishable. Fish meal contains histamine and its compounds, which is easy to cause muscle and stomach erosion in poultry, especially the spoilage fish meal, histamine content is higher. When the content of histamine in chicken feed reaches 0.4%, it can cause typical myogastric erosion, while the content of histamine in poor quality fish meal can be as high as 5% and above, and its harm can be imagined. The smelly, rancid or rancid smell of inferior fish meal will also affect the palatability and nutritional value of the feed.

　　4. Easy to pollute. If not properly processed or transported or preserved, fish meal can easily be contaminated by many harmful microorganisms such as Escherichia coli, Salmonella, Clostridium botulinum, Bacillus cereus and Aspergillus flavus, which can harm the health of farmed animals and even lead to death. According to the relevant departments, the great-grandparent chicken diet does not use fish meal, and the great-grandparent chicken does not use or use less fish meal. H food without fish meal has been developed in China, which not only reduces the cost of feed, but also benefits the health of breeding chickens, and is generally welcomed by chicken farms.

　　5. Easy to poison. Fish meal contains a certain amount of salt, the salt content of imported fish meal is 1.5% ~ 2.5%, the salt content of domestic fish meal is 4% ~ 5%, but due to the raw materials, processing technology and other factors, some fish meal salt content as high as 15% ~ 20%. If the salt in fish meal is neglected in the preparation of feed, it may lead to poisoning of livestock and poultry, especially the death of chicks.

　　6. Adulteration. The price of fishmeal is high and the profit is big. Illegal traders often adulterate fishmeal or adulterate fishmeal to get huge profits. The most common is the incorporation of cake feed and a strong fishy taste of additives. Farmers must pay attention to identify the quality of fish meal to prevent losses caused by adulteration, shoddy and so on.

　　7. Easy to affect livestock and poultry product quality. Fish meal has fishy smell and should not be used to feed dairy animals, otherwise it will affect the quality of milk and cause economic losses. Improper use of fish meal during chicken feeding can also lead to the odor of eggs and chicken, affecting the taste of human beings.

　　二、meat and bone meal

　　Meat and bone meal can be divided into meat meal and bone meal. Those with phosphorus content below 4.4% are meat meal and those with phosphorus content above 4.4% are bone meal. Meat and bone meal has the characteristics of rich nutrition, high absorption rate and low price. It is a high-quality supplementary feed for protein, calcium and phosphorus, which is widely used in the production of pigs and chickens. The dosage should not exceed 6% of the chicken feed and 5% of the feed for breeding pigs and finishing pigs. Main disadvantages of meat and bone meal:

　　1. Unstable composition. The content of nutrients in meat and bone meal is closely related to processing raw materials, while the composition of scraps in food processing plants is complex and not fixed, which makes the composition of meat and bone meal products unstable, and quality inspection must be carried out before use.

　　2. It goes off easily. Meat and bone meal is rich in protein and fat. Under high temperature and high humidity, it is easy to oxidize and decompose, and is easily contaminated by microorganisms and other chemicals. Therefore, meat and bone meal products should not be stored for too long to avoid quality degradation. Add antioxidants and preservatives when you have to store them.

　　3. Limited use. Meat and bone meal should not be added to ruminant animal feed, because meat and bone meal produced in infected areas may cause the spread of mad cow disease and scrapie in sheep, and its palatability is poor.

　　三、feather meal

　　Feather powder is a product formed by hydrolyzing poultry clean feathers under high pressure by steam. Because the disulfide and sulfur-hydrogen bonds in the feather powder structure were broken, the protein was partially hydrolyzed, and the chemical structure of the feather fiber changed. Therefore, the digestibility of the feather powder protein could reach 75%. The biggest characteristic of feather meal is its high protein content, generally around 80%, which is higher than that of fish meal. Feather meal is also characterized by high glycine, serine and isoleucine content, which reach 6.3%, 9.3% and 5.3% respectively, and cystine content reaches 4%, which is the highest among all feeds. In addition, feather meal also contains a variety of trace elements, selenium content is second only to fish meal and rapeseed cake. Feather powder is a good protein supplement feed. The feather powder in chicken feed should be 4%, and that in pig feed should be 3% ~ 5%.

　　Fur animals such as mink and blue fox are prone to trichosis. It has been proved in practice that if feather powder is added into the feed, the daily dosage should be 3 ~ 5 grams, and appropriate amount of linoleic acid, inositol and Vitamin B is added at the same time, it will be significantly improved after 1 week of feeding. After 3 weeks of feeding, it can be eradicated. In addition, adding feather powder in chicken feed can also treat feather pecking disease.

　　The main disadvantages of feather powder:

　　1. Poor quality. Feather powder protein content high, but quality is poorer, amino acid imbalance, lack of lysine and methionine and tryptophan, histidine, etc., as a result, feather meal protein biological titer is low, coupled with poor palatability, only as a protein supplement material, must with other animal or vegetable protein feed collocation is used to obtain good feeding effect.

　　2. Poor palatability. Feather powder will break down some small molecular polypeptides during hydrolysis, exposing hydrophobic amino acid residues, which will stimulate the taste buds to present a bitter taste. During the chemical treatment of feathers, they also produce a bad smell. Both bitter and foul smells affect the palatability of the powder.

　　3. Limited use. Hydrolyzed feather meal cannot be degraded in the rumen and the Ministry of Agriculture stipulates that feather meal shall not be applied to ruminants.

　　四、Blood powder

　　The crude protein content of blood meal is up to 80% ~ 93%, and the lysine content is up to 6% ~ 8%. The content of blood powder iron is also very high, up to L grams, kg, is an important feed for iron.

　　The main disadvantages of blood meal:

　　1. Uneven composition. The amino acid content of blood meal is very unbalanced, high lysine content, but low methionine and arginine content, almost zero isoleucine content, calcium and phosphorus content is very low. As a protein supplement feed, attention should be paid to balance nutrition.

　　2. Processing technology affects digestibility. The digestibility of blood meal made by spray method and fermentation method is higher, but the digestibility of blood meal made by ordinary drying method is lower, plus the palatability is not good, so the dosage of chicken feed should not exceed 2%, the dosage of pig feed should not exceed 5%, but the piglet feed should not use blood meal.

　　3. Harder to keep. Blood powder moisture absorbability is strong, easy to be wet, agglomerate, moldy, corrupt, also easy to be polluted by microorganism, therefore, pay attention to moistureproof, mildew proof, pollution proof when saving blood powder. Farmers try not to preserve blood meal for a long time.

　　五、silkworm chrysalis meal

　　The crude protein content of whole silkworm chrysalis powder is about 54% and the crude fat content is about 22%. Defatted silkworm chrysalis meal crude protein content about 64%, crude fat content about 4%. Silkworm chrysalis powder contains many B vitamins (especially B vitamins), methionine, lysine, tryptophan, leucine and isoleucine, etc. It is an ideal component to balance the El dietary amino acids of livestock and poultry.

　　Main disadvantages of silkworm chrysalis powder:

　　1. Uneven composition. The contents of arginine, calcium and phosphorus in silkworm chrysalis powder are relatively low.

　　2. Dosage is limited. Silkworm chrysalis powder has the peculiar smell of silkworm chrysalis, the dosage should be restricted, otherwise it may make livestock and poultry products with peculiar smell. With the amount of silkworm chrysalis powder in the diet, broiler chicken feed to 2.5%. Five percent is appropriate, with no more than two percent feed for laying hens and two percent feed for pigs.

　　3. Harder to keep. Silkworm chrysalis powder contains a certain amount of fat, the fat content of full fat silkworm chrysalis powder is higher, preservation should pay attention to moistureproof, anti-pollution, anti-corruption, avoid producing foul odor.

　　六、Single cell protein feed

　　Single cell protein feed is a new kind of protein feed products. Due to different biological populations, the protein content of this kind of feed is obviously different, for example, the protein content of bacteria is 69% ~ 80%, yeast protein content is 45% ~ 55%, mold protein content is 30% ~ 50%, algae protein content is 60% ~ 70%. Adding single-cell protein feed into the diet can improve the feed utilization rate, enhance the body's immunity, and improve the lean meat rate of pigs, the egg yield of laying hens and the milk yield of cows.

　　Disadvantages of single cell protein feed:

　　Low digestibility. Toadstool peptides in single cell protein feed can bind to feed protein and affect protein digestion. Single-celled protein also contains some indigestible substances (such as mannan), which have a certain effect on the digestion of dry matter in feed. Therefore, the digestibility of protein in single-cell protein feed is 10% ~ 15% lower than that of conventional protein.

　　2. Poor palatability. Single-celled protein feeds made from yeast have a bitter taste and poor palatability, especially for cattle. Use single cell protein feed, the amount of general control in 5% ~ 10%.

　　3. Big side effects. The content of nucleic acid in the single-cell protein feed is relatively high, and the purine bases in the nucleic acid will form uric acid after metabolism. If the dosage is too large, the formation of uric acid will be too much, which will precipitate or crystallize in the joints along with the blood circulation, which may cause gout or rheumatoid arthritis. Single-celled protein feeds should not exceed 15% of the total protein in the diet.

　　4. Poor security. The substrate for the production of single-cell protein feeds comes from a wide range of sources, especially when industrial and agricultural wastes are used, which may cause the products to carry toxic substances such as certain heavy metals, pesticide residues and pathogenic bacteria. Therefore, the use of single-celled protein feed may have potential safety hazards, farmers must choose the qualified products produced by regular manufacturers when using single-celled protein feed.