Poultry protein and amino acid deficiency
Poultry protein and amino acid deficiency refers to insufficient protein intake or excessive consumption of poultry and one or several amino acid deficiencies.
1. Insufficient protein and amino acid content in feed The content of protein and amino acid in common poultry feed is quite different. Grain and bran feeds have less protein content and incomplete nutritional value, especially lack of methionine and lysine, while animal protein feeds have higher protein content and more complete types of amino acids. If the type of feed is single, the diet is unreasonable, and the animal protein feed is lacking for a long time, it can cause the lack of protein and amino acids. In addition, the protein and amino acid requirements of poultry are closely related to the type, breed, age, production performance, environmental temperature and dietary energy level of poultry. For example, broiler and breeder chicks require the highest amounts of protein and amino acids in the brooding stage, and then gradually decrease as the chicks grow; broiler chickens have higher requirements than egg-type poultry; poultry in the growth stage have higher requirements than adult birds High; laying hens need a large amount from the initial laying to the peak laying period, which will decrease as the egg production decreases; the feed intake decreases when the temperature is high, and the protein content in the feed should also be increased at this time; the dietary energy level is high At this time, the poultry will reduce the feed intake by itself, and the protein and amino acid content of the feed must also be increased. Therefore, if the difference in protein and amino acid requirements of the above-mentioned factors is ignored in poultry breeding, and a certain formula is used unchanged for a long time, it will also cause a lack of protein and amino acids.
2. Unbalanced matching of amino acids Due to the lack of feed protein, amino acid deficiency and imbalance will inevitably occur; even the lack of one amino acid will affect the utilization of other amino acids and cause the lack of multiple amino acids. For example, lysine, methionine and tryptophan in the essential amino acids are restricted when poultry uses other amino acids to synthesize protein (called limiting amino acids). Cereals such as corn and sorghum, bran feed), and other amino acids cannot be utilized, resulting in a deficiency. There is also a special relationship between certain amino acids, such as tyrosine and cystine, which can be converted from phenylalanine and methionine, respectively, in poultry. When the former two are deficient, the demand for the latter two amino acids will increase, resulting in the deficiency of phenylalanine and methionine. Although glycine can be synthesized in poultry, it is synthesized slowly in chicks, which cannot meet the needs of rapid growth of chicks. In addition, the lack of certain amino acids can also be caused by ill-considered interactions and transformation relationships between certain amino acids.
3. In the process of phlegm disease, the poultry's feed intake will be reduced, the appetite will be decreased or eliminated, and the protein intake will be insufficient. Such as avian pasteurellosis, coccidiosis, inflammation of the digestive tract and digestive dysfunction, all of which can affect the digestion, absorption and utilization of protein by poultry; some febrile venereal diseases, chronic wasting diseases, such as avian tuberculosis, Marek's disease, Avian leukemia, digestive tract nematode disease, etc. can increase the consumption of protein in poultry; when the content of sugar and fat in the diet is insufficient, it not only strengthens protein decomposition, but also affects protein synthesis.
Protein is the material basis of life and is the main component of poultry cells and eggs. Muscles, skin, feathers, nerves, internal organs, enzymes, hormones, antibodies, etc. all contain a large amount of protein, and participate in the body's metabolic activities. Therefore, protein and amino acids not only maintain the life of poultry, but also have a very close relationship with the growth, development, genetics, disease resistance and egg formation of poultry. When poultry is deficient in protein and amino acids, its metabolism will be hindered, resulting in growth inhibition, reduced productivity, and reduced disease resistance.
3. Clinical symptoms
When the chicks lack protein and amino acids, they show slow growth and development, loose and dull feathers, weakness, lack of energy, poor appetite, slightly low body temperature, and often crowded piles; plasma colloid osmotic pressure is often low and subcutaneous edema often occurs, red blood cells The total number and hemoglobin decreased leading to anemia, and the weight gain was not as expected.
In addition to the above symptoms, adult birds mainly show progressive weight loss, decreased or stopped egg production; male birds have poor sperm motility, low fertilization rate and hatching rate.
Whether it is a young bird or an adult bird, due to the decrease of albumin and globulin content in the blood, the disease resistance of the sick bird is poor, and it is often secondary to a variety of other diseases and causes death.
4. Pathological changes
At autopsy, most of the sick birds were found to be emaciated, with subcutaneous fat disappearing, edema, pale and atrophic muscles, thin blood and poor coagulation, effusion in the chest, abdominal cavity and pericardium, almost no fat in the whole body, and jelly-like coronary fat in the heart.
Based on clinical symptoms (slow growth, weight loss, anemia, decreased productivity, etc.) and pathological changes (fat loss, muscle atrophy, edema and fluid accumulation), combined with the analysis of the feed, it is generally not difficult to make a diagnosis. In addition, when suffering from this disease, the total protein, albumin, globulin, total erythrocyte and hemoglobin content in the blood were significantly decreased, and the determination of these indicators when necessary is also helpful for the diagnosis of this disease.
1. To ensure the protein content in poultry diets When formulating poultry diets, protein is an important factor in addition to energy, vitamins and minerals. In general, grains and brans have less protein content, and the nutritional value of protein is not complete. Therefore, plant-based and animal-based protein feeds (such as soybean cake, cottonseed cake, rapeseed cake, fish meal, blood meal, bone and meat meal, etc.) should be appropriately matched in the diet. The content of protein feed in chicken diets should be about 20% for chicks and broilers, and 14%-16% for laying hens, of which animal protein feed should be no less than 3%.
2. Pay attention to the balance of various amino acids and the insufficiency of limiting amino acids will affect the utilization of other amino acids. Therefore, the diet should pay attention to supplement the feed and additives rich in these amino acids. Pay attention to the role of certain amino acids, such as arginine, lysine, valine, leucine, isoleucine, and add one or two amino acids of a certain group to the diet. should also increase the amount of other amino acids in the same group, otherwise it will cause deficiency.
3. When adjusting the feed formula in time to determine the protein and amino acid requirements of poultry, it should be adjusted according to different factors such as the type, breed, age, productivity, ambient temperature, and energy level of the diet. It cannot be fixed for a long time. Use a certain feed formula differently.
4. Pay attention to feed processing and preparation. When compounding feed, attention should be paid to the quality of protein. Poor quality protein contains incomplete types of essential amino acids and less content. In addition, in feed preparation methods, such as heat-treated beans, when the temperature is too high, the activity of lysine and arginine will be reduced, cystine will be destroyed, and the nutritional value of its protein will be reduced.