Detailed Explanation of the Principles of Broiler Feed Formula Design
Principles of Broiler Feed Formula Design
Principles of Broiler Feed Formula Design
(1) Balance of energy and protein
For broilers to carry out life activities, they must have a certain amount of basic energy. Energy comes from carbohydrates, fats and proteins in the feed. However, protein is not only the basic substance constituting body cells, but also the raw material for various functional enzymes and hormones. Therefore, using protein merely as an energy source is a huge waste.
Broilers consume feed mainly to meet their necessary energy needs. When energy needs are met, feeding stops. If the diet is deficient in energy, protein must be broken down to meet energy needs, resulting in a waste of protein. But when energy is too high, the chicken's feed intake decreases, which in turn causes protein deficiency and affects growth. Therefore, the content of essential nutrients such as protein, vitamins and minerals in the feed should be in appropriate proportion to the energy in the feed, so as to achieve the goals of less feed consumption, faster weight gain and more egg production.
In addition to the metabolizable energy in the feed, the feed intake of chickens is greatly affected by the house temperature in terms of energy requirements. The variation is smallest at the optimal temperature, but energy requirements increase significantly at low temperatures, which must be noted.
(2) Balance of protein and amino acids
The main component of animal body cells is protein, and chicken body protein is converted from feed protein. Therefore, whether feed protein can be used economically and effectively is the key to the cost of raising chickens.
Protein is a kind of high-molecular organic compound, which forms various amino acids through hydrolysis in the body. Therefore, amino acids are the basic units constituting protein. So-called good-quality feed protein means that the protein in the diet contains all the amino acids needed by chickens and in appropriate proportions; poor quality indicates that the amino acids contained in the protein are incomplete or in improper proportions. Therefore, the biological value of protein is not determined by how much protein is contained, but by how high its utilization rate is. Only when various essential amino acids are balanced can the utilization rate of protein be improved. There are many kinds of amino acids, but about 20 or more constitute protein. Of these, half cannot be synthesized in the chicken's body or cannot be synthesized in sufficient quantities to meet needs and must be supplied by feed. Such amino acids are called essential amino acids. If the intake of essential amino acids is insufficient, it is difficult to bring the chicken's production capacity into full play.
According to experiments, adding methionine to a diet containing 15% crude protein has an extremely significant weight-gain effect (P<0.01)，添加赖氨酸对鸡虽有促进生长作用，但不显著(P>0.05). Many experiments show that in ordinary feed formulation, methionine or methionine plus cystine (which have a synergistic effect in the body) is the first limiting essential amino acid, followed by lysine and tryptophan. Therefore, when preparing diets, the above 3-4 amino acids should be satisfied as much as possible.
Using a mixture of two or more proteins has a better nutritional effect than feeding each alone. This is because the content of various amino acids in natural proteins is unbalanced. Using several feeds in combination can make up for each other's deficiencies, achieve balance and improve utilization.
(3) Calcium and phosphorus requirements and ratio
Both calcium and phosphorus are major components of bone. 65%-70% of the total minerals in the chicken body are compounds of calcium and phosphorus. Calcium in the bones accounts for 99% of the total in the whole body, and the remaining 1% exists in blood, lymph and other tissues. Calcium plays a very important role in the formation of eggshells, blood coagulation, and, together with sodium and potassium, in maintaining the normal functions of the heart, muscles and nerves and the acid-base balance in the body. Phosphorus in bone accounts for 80% of the total phosphorus in the whole body, and accounts for 0.8% of the fat-free matter in the chicken body. Most of it is in an organic state and is related to various metabolisms. It is a component of nucleic acids, high-energy phosphate, phosphoproteins, phospholipids, phosphocreatine and hexose phosphate. The blood also contains some phosphorus.
When preparing diets, in addition to meeting the requirements for calcium and phosphorus, attention should also be paid to the appropriate ratio of calcium to phosphorus according to feeding standards. This is because the absorption of phosphorus is greatly related to the amount of calcium present in the feed. If the calcium-to-phosphorus ratio in the diet is inappropriate, or if they are in a bound state and difficult to dissolve, absorption will decrease and deficiency symptoms will occur. Excessive calcium content is not only harmful to the growth of chicks, but also affects the absorption of phosphorus, magnesium, manganese, zinc and other elements.
In general, the suitable calcium-to-phosphorus ratio is 1.1-1.5:1 for broilers and 5-6:1 for laying hens.
Chickens have a relatively low utilization rate of phytate phosphorus, about 30% for chicks and about 50% for meat chickens; while inorganic phosphorus can be utilized 100%. Therefore, a portion of inorganic phosphorus must be supplemented in the diet, especially when fish meal is lacking in the diet.
(4) Trace elements and vitamins
Most trace elements are components of hormones and enzymes. Like vitamins, they are active substances in the processes of material and energy metabolism and play an irreplaceable role in regulating physical and chemical reactions and osmotic pressure in the body, maintaining body fluid acid-base balance and body metabolism. Compared with livestock, chickens have fewer microorganisms in the digestive tract, and most vitamins cannot be synthesized in the body; although some can be synthesized, they cannot meet needs and must be obtained from feed. The figures for vitamins and trace elements listed in the standards are requirements, and when applied, a safety margin should be added as appropriate according to the chicken flock's ecology, environment, feeding conditions and disease situation. The vitamin values listed in the standards can be used as the supplemental amount, and the content in the feed can be used as the safety margin. For trace elements, it should be determined as appropriate according to the specific conditions of each region and the source of feed, but the supplemental amount of trace elements must not exceed the standard, otherwise poisoning will be caused.
(5) Limit of crude fiber content
Chickens have a high body temperature, grow quickly and have vigorous material metabolism. Therefore, they require a higher nutritional level than other animals. Also, because chickens have no teeth and rely entirely on grit in the gizzard to grind food, and because the intestinal tract is short (the time for food to pass through is also short), and the ceca have little digestive effect on feed, chickens have a relatively low ability to digest crude fiber. If fiber is excessive, the nutritional level will not match the physiological characteristics of chickens, affecting the digestion and absorption of other nutrients and causing feed waste. But when fiber is too little, intestinal peristalsis is insufficient, chickens do not feel full, and vicious habits such as feather pecking are likely to occur. The crude fiber content in chicken diets should preferably be 2.5%-5%.
(6) Balance of animal feed and plant feed
When preparing poultry diets, attention should be paid to the combination of animal feed and plant feed to improve feed utilization efficiency. Commonly used animal feeds include fish meal, shrimp bran, blood meal and silkworm pupae, and fresh fish, shrimp, mussel meat, earthworms and the like can also be used as substitutes. The role of animal feed is mainly to balance essential amino acids, change the fatty acid composition in feed, affect the metabolizable energy value of feed and the balance of vitamins, and influence the reproduction of bacterial flora in the intestinal tract, and it also contains so-called unknown growth factors. When preparing diets, fish meal at 2%-5% is sufficient, and at most no more than 7%; other animal feeds should also preferably not exceed 10%.
(7) Other nutrients in the diet
Water accounts for 60%-70% of the chicken body and plays an important role in digestion, absorption, metabolism and body temperature regulation, so clean and appropriate amounts of drinking water should be provided. The drinking water intake of chickens is affected by factors such as air temperature, humidity, body weight, laying rate, feed composition and feeding restriction conditions.
Salt can provide the sodium ions and chloride ions needed for the normal physiological functions of chickens. When preparing diets, the salt content of fish meal should be taken into account to prevent excessive salt and cause poisoning.
Source: www.feedsos.com
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Nice post, it took me back to my student days.
--------------------------------------
I learned something. It would be even better if there were more basic data.
--------------------------------------
Animal feed is not very easy to use now. The effect of ambient temperature is actually very large.
--------------------------------------
Then what is a more appropriate protein-to-energy ratio for broilers?
(1) Balance of energy and protein
For broilers to carry out life activities, they must have a certain amount of basic energy. Energy comes from carbohydrates, fats and proteins in the feed. However, protein is not only the basic substance constituting body cells, but also the raw material for various functional enzymes and hormones. Therefore, using protein merely as an energy source is a huge waste.
Broilers consume feed mainly to meet their necessary energy needs. When energy needs are met, feeding stops. If the diet is deficient in energy, protein must be broken down to meet energy needs, resulting in a waste of protein. But when energy is too high, the chicken's feed intake decreases, which in turn causes protein deficiency and affects growth. Therefore, the content of essential nutrients such as protein, vitamins and minerals in the feed should be in appropriate proportion to the energy in the feed, so as to achieve the goals of less feed consumption, faster weight gain and more egg production.
In addition to the metabolizable energy in the feed, the feed intake of chickens is greatly affected by the house temperature in terms of energy requirements. The variation is smallest at the optimal temperature, but energy requirements increase significantly at low temperatures, which must be noted.
(2) Balance of protein and amino acids
The main component of animal body cells is protein, and chicken body protein is converted from feed protein. Therefore, whether feed protein can be used economically and effectively is the key to the cost of raising chickens.
Protein is a kind of high-molecular organic compound, which forms various amino acids through hydrolysis in the body. Therefore, amino acids are the basic units constituting protein. So-called good-quality feed protein means that the protein in the diet contains all the amino acids needed by chickens and in appropriate proportions; poor quality indicates that the amino acids contained in the protein are incomplete or in improper proportions. Therefore, the biological value of protein is not determined by how much protein is contained, but by how high its utilization rate is. Only when various essential amino acids are balanced can the utilization rate of protein be improved. There are many kinds of amino acids, but about 20 or more constitute protein. Of these, half cannot be synthesized in the chicken's body or cannot be synthesized in sufficient quantities to meet needs and must be supplied by feed. Such amino acids are called essential amino acids. If the intake of essential amino acids is insufficient, it is difficult to bring the chicken's production capacity into full play.
According to experiments, adding methionine to a diet containing 15% crude protein has an extremely significant weight-gain effect (P<0.01)，添加赖氨酸对鸡虽有促进生长作用，但不显著(P>0.05). Many experiments show that in ordinary feed formulation, methionine or methionine plus cystine (which have a synergistic effect in the body) is the first limiting essential amino acid, followed by lysine and tryptophan. Therefore, when preparing diets, the above 3-4 amino acids should be satisfied as much as possible.
Using a mixture of two or more proteins has a better nutritional effect than feeding each alone. This is because the content of various amino acids in natural proteins is unbalanced. Using several feeds in combination can make up for each other's deficiencies, achieve balance and improve utilization.
(3) Calcium and phosphorus requirements and ratio
Both calcium and phosphorus are major components of bone. 65%-70% of the total minerals in the chicken body are compounds of calcium and phosphorus. Calcium in the bones accounts for 99% of the total in the whole body, and the remaining 1% exists in blood, lymph and other tissues. Calcium plays a very important role in the formation of eggshells, blood coagulation, and, together with sodium and potassium, in maintaining the normal functions of the heart, muscles and nerves and the acid-base balance in the body. Phosphorus in bone accounts for 80% of the total phosphorus in the whole body, and accounts for 0.8% of the fat-free matter in the chicken body. Most of it is in an organic state and is related to various metabolisms. It is a component of nucleic acids, high-energy phosphate, phosphoproteins, phospholipids, phosphocreatine and hexose phosphate. The blood also contains some phosphorus.
When preparing diets, in addition to meeting the requirements for calcium and phosphorus, attention should also be paid to the appropriate ratio of calcium to phosphorus according to feeding standards. This is because the absorption of phosphorus is greatly related to the amount of calcium present in the feed. If the calcium-to-phosphorus ratio in the diet is inappropriate, or if they are in a bound state and difficult to dissolve, absorption will decrease and deficiency symptoms will occur. Excessive calcium content is not only harmful to the growth of chicks, but also affects the absorption of phosphorus, magnesium, manganese, zinc and other elements.
In general, the suitable calcium-to-phosphorus ratio is 1.1-1.5:1 for broilers and 5-6:1 for laying hens.
Chickens have a relatively low utilization rate of phytate phosphorus, about 30% for chicks and about 50% for meat chickens; while inorganic phosphorus can be utilized 100%. Therefore, a portion of inorganic phosphorus must be supplemented in the diet, especially when fish meal is lacking in the diet.
(4) Trace elements and vitamins
Most trace elements are components of hormones and enzymes. Like vitamins, they are active substances in the processes of material and energy metabolism and play an irreplaceable role in regulating physical and chemical reactions and osmotic pressure in the body, maintaining body fluid acid-base balance and body metabolism. Compared with livestock, chickens have fewer microorganisms in the digestive tract, and most vitamins cannot be synthesized in the body; although some can be synthesized, they cannot meet needs and must be obtained from feed. The figures for vitamins and trace elements listed in the standards are requirements, and when applied, a safety margin should be added as appropriate according to the chicken flock's ecology, environment, feeding conditions and disease situation. The vitamin values listed in the standards can be used as the supplemental amount, and the content in the feed can be used as the safety margin. For trace elements, it should be determined as appropriate according to the specific conditions of each region and the source of feed, but the supplemental amount of trace elements must not exceed the standard, otherwise poisoning will be caused.
(5) Limit of crude fiber content
Chickens have a high body temperature, grow quickly and have vigorous material metabolism. Therefore, they require a higher nutritional level than other animals. Also, because chickens have no teeth and rely entirely on grit in the gizzard to grind food, and because the intestinal tract is short (the time for food to pass through is also short), and the ceca have little digestive effect on feed, chickens have a relatively low ability to digest crude fiber. If fiber is excessive, the nutritional level will not match the physiological characteristics of chickens, affecting the digestion and absorption of other nutrients and causing feed waste. But when fiber is too little, intestinal peristalsis is insufficient, chickens do not feel full, and vicious habits such as feather pecking are likely to occur. The crude fiber content in chicken diets should preferably be 2.5%-5%.
(6) Balance of animal feed and plant feed
When preparing poultry diets, attention should be paid to the combination of animal feed and plant feed to improve feed utilization efficiency. Commonly used animal feeds include fish meal, shrimp bran, blood meal and silkworm pupae, and fresh fish, shrimp, mussel meat, earthworms and the like can also be used as substitutes. The role of animal feed is mainly to balance essential amino acids, change the fatty acid composition in feed, affect the metabolizable energy value of feed and the balance of vitamins, and influence the reproduction of bacterial flora in the intestinal tract, and it also contains so-called unknown growth factors. When preparing diets, fish meal at 2%-5% is sufficient, and at most no more than 7%; other animal feeds should also preferably not exceed 10%.
(7) Other nutrients in the diet
Water accounts for 60%-70% of the chicken body and plays an important role in digestion, absorption, metabolism and body temperature regulation, so clean and appropriate amounts of drinking water should be provided. The drinking water intake of chickens is affected by factors such as air temperature, humidity, body weight, laying rate, feed composition and feeding restriction conditions.
Salt can provide the sodium ions and chloride ions needed for the normal physiological functions of chickens. When preparing diets, the salt content of fish meal should be taken into account to prevent excessive salt and cause poisoning.
Source: www.feedsos.com
--------------------------------------
Nice post, it took me back to my student days.
--------------------------------------
I learned something. It would be even better if there were more basic data.
--------------------------------------
Animal feed is not very easy to use now. The effect of ambient temperature is actually very large.
--------------------------------------
Then what is a more appropriate protein-to-energy ratio for broilers?