Digestion of feed nutrients differs depending on the type, species, and age of the farmed animals. Even if the same animal is different due to the characteristics and composition of the feed, understanding and applying this knowledge will create a good digestive condition for the farmed animals and improve the feed. Digestibility, thereby increasing the production of farmed animals is very beneficial.
(1) The influence of protein content in feed: whether the protein content in the feed will affect the digestion and absorption rate of the protein. Due to changes in protein content in the study, other feed components also changed accordingly, so the change in digestion and absorption rate is due to the influence of feed ingredients, or due to the influence of protein content, which brings certain difficulties to the judgment. Chi Zhe (1956) fed a mixture of casein+starch+salt to juvenile clams and observed a low protein digestion and absorption rate at 10% protein content and a low protein digestion rate of 20-40%. difference. He believes that the reason for the low protein content and low digestion and absorption rate may be influenced by the endogenous N component. In another study, he found that when the protein content is low, the apparent digestive absorption rate is also small, but if the internal cause When the amount of protein N is modified by 0.04 mg/g body weight, it is approximately the same as the true digestive absorption rate, and it is considered that the decrease in apparent digestibility seen at a low protein content is not due to the outstanding performance of adding starch. But due to the endogenous protein state N.
MacConson studied the digestibility of amino acids in shrimp, and found that there was a positive correlation between amino acid digestion and absorption and its content.
(2) Effect of water temperature: Wang Kexing (1984) pointed out that in the water temperature range of 20-32°C, the growth rate of the prawns will increase with the increase of water temperature. Whether the water temperature has an effect on the growth rate will improve the digestion and absorption rate. reflect? Xie Baohua et al. (1983) reported that there was no significant difference in digestion rate and protein digestibility between the diets at different water temperatures of 25°C and 30°C. Makansen et al. (1988) used 51 Cr2O3 as the indicator substance to incorporate small trash fish and shrimp in the experiment. The results showed that the digestion and absorption rate was between 85.90-88.67% in the range of 20-30°C. Does not significantly affect the protein digestion and absorption rate.
(3) Effect of crushed particle size: shrimps were fed with 18 mesh, 40 mesh, 60 mesh, 80 mesh, 100 mesh sieved peanut meal to measure their digestion and absorption rate. The results showed that the protein digestion and absorption rate of the peanut meal with 18 mesh sieve was reduced to below 80%, which is obviously because the granules are too coarse and the digestive liquid is difficult to infiltrate; peanut cake powder sieved from 40 mesh to 100 mesh, which There is no significant difference in protein digestion and absorption rate, and it is basically at the same level. The relationship between grain size and digestibility of white fishmeal was studied in rice leaves and wild rainbow trout with a weight of 10 g and 100 g. It was observed that the particles were large and the digestibility was poor. The smaller the particles, the better the digestion. If it was too fine, no difference.
(4) Effects of different drying methods: There was no significant difference in protein digestibility between the peanut meal fed with the dried, dried, and far-infrared drying at 60°C. The digestibility was about 91%. Dryers at 60°C were slightly higher than those who drank; those dried at 100°C decreased their digestibility to 88.9%. In addition, it was found that dried peanut meal dried at 105°C was anorectic to shrimps, which may be caused by high temperature treatment, denaturalization of proteins, structural changes, and indigestion. Far-infrared dried peanut cake, its amino acid digestibility compared with 60 °C dried, threonine and proline increased slightly, the remaining amino acid digestibility difference is not.
Heating for a long time will denature proteins and produce products that are not affected by digestive enzymes. This is because the heat treatment causes a browning reaction between tryptophan, lysine, phenylalanine, methionine, and sugar, and this browning reaction product is difficult to decompose by digestive enzymes, so that the rate of digestion and absorption of the protein is reduced.
(5) Influence of digestion time: The extent to which the protein is digested in the digestive tract depends on the time when the digestive enzyme acts, but also on the concentration of the digestive enzyme, the pH of the enzyme's environment, and the temperature. When the enzyme action time is different, the digestion and absorption rate will change. From feeding to excretion, all the required digestion time varies depending on the type of fish and shrimp. When the bait is re-ingested, the contents of the digestive tract move sharply. Therefore, the time for digesting the first bait is shortened, and the digestion and absorption rate is reduced. That is to say, the time for feeding the feed should be taken into consideration, and the residence time of the fish and shrimp in the digestive tract after feeding is taken into account.
(6) Effect of added sugars: The addition of 10% sucrose to shrimps in peanut cakes can cause a significant decrease in protein digestibility, with the greatest reduction in lysine. In peanut meal, 10% glucose was added. In addition to serine and glutamic acid, the other 13 amino acids all decreased in varying degrees, but except for a large decrease in proline, the others were not significant. Sen (1989) reported that.
The extent to which protein is added to the diet to cause a decrease in protein digestion and absorption rate varies depending on the type of fish. Chih Chih (1955) found that the casein content was 40-20% and the apparent starch digestion rate was 97-95% when the starch content was 50-70%. It is basically the same, but when the casein content is 10%, and the starch is added to 80%, the apparent digestion and absorption rate is reduced to 89%.
Freshwater salmon, although carnivorous, can also make good use of starch. The protein digestion and absorption rate of seawater carnivorous fish and fish, when the starch is increased, the digestibility is decreased. The fish is a typical carnivorous fish with strong protease activity and very weak amylase activity. Due to its extremely weak amylase activity, it does not decompose the starch well and leaves the starch paste in the intestine, hindering the digestion of the protein.
(7) The effect of adding vitamins: Vitamins have a significant impact on digestion and absorption, such as the lack of B vitamins, such as the lack of vitamins A and C, can lead to indigestion. Vitamin B6 as a coenzyme participates in many metabolic reactions and plays an important role in amino acid metabolism, which can promote the rate of amino acid entry into cells. The addition of B6 to the feed increases the digestibility of the protein from 91.9% to 93.6%; the digestibility of leucine, isoleucine, phenylalanine, lysine, histidine and arginine With significant improvements, B6 is also an indispensable vitamin in the nutritional study of Japanese shrimp.
(8) The effect of adding cellulose: When adding a small amount of cellulose to the bait, cellulose can cause feces to form and stimulate intestinal peristalsis to promote digestion. However, if cellulose is added in excess, it will affect the rate of protein digestion and absorption. Reduces growth and can cause fecal clogging and death. The tolerable amounts of cellulose and chitin indigestibles in different fish feeds are different, and catfish and the like can tolerate considerable amounts. The cellulose content in the feed is greater than 4.5% and the growth of shrimp will be affected.
(9) Effect of adding trypsin: The digestion and absorption rate of protein in Peruvian fishmeal was significantly improved by using trypsin. For amino acids, except for proline, the absorption rate of other amino acids has different degrees. improve. Of the essential amino acids, the increase in threonine, methionine, leucine, isoleucine, lysine, arginine, and histidine is significant. Treatment of peanut cake with trypsin increased its protein digestion and absorption rate by 95.5%, which is close to the digestion and absorption rate of fresh shellfish meat. For amino acids, except for methionine, the digestibility of other amino acids has increased significantly. In particular, the increase in lysine was even greater, with an absolute value of 8.8%. The original absorption rate of threonine and methionine was low. After trypsin treatment, the absorption rate reached more than 90%. It can be seen that treatment with trypsin is a good way to improve the utilization of feed.
(10) Effect of adding alginate: Alginate or kelp (mainly brown algae) is one of the commonly used binders for shrimp. There was no difference in the protein digestibility between the peanut cakes with alginate and those without algin, except that the digestibility of lysine and proline decreased to some extent, but there was no significant difference in other amino acids. Qian Jing Jian (1964) used 5% alginate-bound feed to feed shrimp, and the protein digestibility declined significantly. This may be due to excessive use or treatment associated with the use of calcium chloride.
(11) Effect of Addition of Free Amino Acids: The experiments of Meadson (1987) pointed out that most of the free amino acids in the feed were absorbed by the midgut glands before entering the intestine. After the addition of free amino acids, the digestion and absorption rates of threonine, glycine, valine, leucine, isoleucine, phenylalanine and lysine in the protein in the midgut have decreased significantly. Free amino acids not only can not be absorbed simultaneously with the bound amino acids, but also seriously affect the synchronization of the absorption of other essential amino acids, so that amino acids can not be balanced and complementary, thus affecting the binding rate of free amino acids and the protein efficiency of the entire beverage, which is in the compound feed The reason why the effect of directly adding free amino acid feeds is not ideal. The experimental results also show that the utilization rate of free lysine in the continuous feeding group is higher than that of the one-time feeding group. Because continuous feeding provides a chance for lysine to be absorbed synchronously with other amino acids, so as to achieve a balanced complement of amino acids, it can be seen that an appropriate increase in the number of feedings helps increase the binding rate of free amino acids.
(1) The influence of protein content in feed: whether the protein content in the feed will affect the digestion and absorption rate of the protein. Due to changes in protein content in the study, other feed components also changed accordingly, so the change in digestion and absorption rate is due to the influence of feed ingredients, or due to the influence of protein content, which brings certain difficulties to the judgment. Chi Zhe (1956) fed a mixture of casein+starch+salt to juvenile clams and observed a low protein digestion and absorption rate at 10% protein content and a low protein digestion rate of 20-40%. difference. He believes that the reason for the low protein content and low digestion and absorption rate may be influenced by the endogenous N component. In another study, he found that when the protein content is low, the apparent digestive absorption rate is also small, but if the internal cause When the amount of protein N is modified by 0.04 mg/g body weight, it is approximately the same as the true digestive absorption rate, and it is considered that the decrease in apparent digestibility seen at a low protein content is not due to the outstanding performance of adding starch. But due to the endogenous protein state N.
MacConson studied the digestibility of amino acids in shrimp, and found that there was a positive correlation between amino acid digestion and absorption and its content.
(2) Effect of water temperature: Wang Kexing (1984) pointed out that in the water temperature range of 20-32°C, the growth rate of the prawns will increase with the increase of water temperature. Whether the water temperature has an effect on the growth rate will improve the digestion and absorption rate. reflect? Xie Baohua et al. (1983) reported that there was no significant difference in digestion rate and protein digestibility between the diets at different water temperatures of 25°C and 30°C. Makansen et al. (1988) used 51 Cr2O3 as the indicator substance to incorporate small trash fish and shrimp in the experiment. The results showed that the digestion and absorption rate was between 85.90-88.67% in the range of 20-30°C. Does not significantly affect the protein digestion and absorption rate.
(3) Effect of crushed particle size: shrimps were fed with 18 mesh, 40 mesh, 60 mesh, 80 mesh, 100 mesh sieved peanut meal to measure their digestion and absorption rate. The results showed that the protein digestion and absorption rate of the peanut meal with 18 mesh sieve was reduced to below 80%, which is obviously because the granules are too coarse and the digestive liquid is difficult to infiltrate; peanut cake powder sieved from 40 mesh to 100 mesh, which There is no significant difference in protein digestion and absorption rate, and it is basically at the same level. The relationship between grain size and digestibility of white fishmeal was studied in rice leaves and wild rainbow trout with a weight of 10 g and 100 g. It was observed that the particles were large and the digestibility was poor. The smaller the particles, the better the digestion. If it was too fine, no difference.
(4) Effects of different drying methods: There was no significant difference in protein digestibility between the peanut meal fed with the dried, dried, and far-infrared drying at 60°C. The digestibility was about 91%. Dryers at 60°C were slightly higher than those who drank; those dried at 100°C decreased their digestibility to 88.9%. In addition, it was found that dried peanut meal dried at 105°C was anorectic to shrimps, which may be caused by high temperature treatment, denaturalization of proteins, structural changes, and indigestion. Far-infrared dried peanut cake, its amino acid digestibility compared with 60 °C dried, threonine and proline increased slightly, the remaining amino acid digestibility difference is not.
Heating for a long time will denature proteins and produce products that are not affected by digestive enzymes. This is because the heat treatment causes a browning reaction between tryptophan, lysine, phenylalanine, methionine, and sugar, and this browning reaction product is difficult to decompose by digestive enzymes, so that the rate of digestion and absorption of the protein is reduced.
(5) Influence of digestion time: The extent to which the protein is digested in the digestive tract depends on the time when the digestive enzyme acts, but also on the concentration of the digestive enzyme, the pH of the enzyme's environment, and the temperature. When the enzyme action time is different, the digestion and absorption rate will change. From feeding to excretion, all the required digestion time varies depending on the type of fish and shrimp. When the bait is re-ingested, the contents of the digestive tract move sharply. Therefore, the time for digesting the first bait is shortened, and the digestion and absorption rate is reduced. That is to say, the time for feeding the feed should be taken into consideration, and the residence time of the fish and shrimp in the digestive tract after feeding is taken into account.
(6) Effect of added sugars: The addition of 10% sucrose to shrimps in peanut cakes can cause a significant decrease in protein digestibility, with the greatest reduction in lysine. In peanut meal, 10% glucose was added. In addition to serine and glutamic acid, the other 13 amino acids all decreased in varying degrees, but except for a large decrease in proline, the others were not significant. Sen (1989) reported that.
The extent to which protein is added to the diet to cause a decrease in protein digestion and absorption rate varies depending on the type of fish. Chih Chih (1955) found that the casein content was 40-20% and the apparent starch digestion rate was 97-95% when the starch content was 50-70%. It is basically the same, but when the casein content is 10%, and the starch is added to 80%, the apparent digestion and absorption rate is reduced to 89%.
Freshwater salmon, although carnivorous, can also make good use of starch. The protein digestion and absorption rate of seawater carnivorous fish and fish, when the starch is increased, the digestibility is decreased. The fish is a typical carnivorous fish with strong protease activity and very weak amylase activity. Due to its extremely weak amylase activity, it does not decompose the starch well and leaves the starch paste in the intestine, hindering the digestion of the protein.
(7) The effect of adding vitamins: Vitamins have a significant impact on digestion and absorption, such as the lack of B vitamins, such as the lack of vitamins A and C, can lead to indigestion. Vitamin B6 as a coenzyme participates in many metabolic reactions and plays an important role in amino acid metabolism, which can promote the rate of amino acid entry into cells. The addition of B6 to the feed increases the digestibility of the protein from 91.9% to 93.6%; the digestibility of leucine, isoleucine, phenylalanine, lysine, histidine and arginine With significant improvements, B6 is also an indispensable vitamin in the nutritional study of Japanese shrimp.
(8) The effect of adding cellulose: When adding a small amount of cellulose to the bait, cellulose can cause feces to form and stimulate intestinal peristalsis to promote digestion. However, if cellulose is added in excess, it will affect the rate of protein digestion and absorption. Reduces growth and can cause fecal clogging and death. The tolerable amounts of cellulose and chitin indigestibles in different fish feeds are different, and catfish and the like can tolerate considerable amounts. The cellulose content in the feed is greater than 4.5% and the growth of shrimp will be affected.
(9) Effect of adding trypsin: The digestion and absorption rate of protein in Peruvian fishmeal was significantly improved by using trypsin. For amino acids, except for proline, the absorption rate of other amino acids has different degrees. improve. Of the essential amino acids, the increase in threonine, methionine, leucine, isoleucine, lysine, arginine, and histidine is significant. Treatment of peanut cake with trypsin increased its protein digestion and absorption rate by 95.5%, which is close to the digestion and absorption rate of fresh shellfish meat. For amino acids, except for methionine, the digestibility of other amino acids has increased significantly. In particular, the increase in lysine was even greater, with an absolute value of 8.8%. The original absorption rate of threonine and methionine was low. After trypsin treatment, the absorption rate reached more than 90%. It can be seen that treatment with trypsin is a good way to improve the utilization of feed.
(10) Effect of adding alginate: Alginate or kelp (mainly brown algae) is one of the commonly used binders for shrimp. There was no difference in the protein digestibility between the peanut cakes with alginate and those without algin, except that the digestibility of lysine and proline decreased to some extent, but there was no significant difference in other amino acids. Qian Jing Jian (1964) used 5% alginate-bound feed to feed shrimp, and the protein digestibility declined significantly. This may be due to excessive use or treatment associated with the use of calcium chloride.
(11) Effect of Addition of Free Amino Acids: The experiments of Meadson (1987) pointed out that most of the free amino acids in the feed were absorbed by the midgut glands before entering the intestine. After the addition of free amino acids, the digestion and absorption rates of threonine, glycine, valine, leucine, isoleucine, phenylalanine and lysine in the protein in the midgut have decreased significantly. Free amino acids not only can not be absorbed simultaneously with the bound amino acids, but also seriously affect the synchronization of the absorption of other essential amino acids, so that amino acids can not be balanced and complementary, thus affecting the binding rate of free amino acids and the protein efficiency of the entire beverage, which is in the compound feed The reason why the effect of directly adding free amino acid feeds is not ideal. The experimental results also show that the utilization rate of free lysine in the continuous feeding group is higher than that of the one-time feeding group. Because continuous feeding provides a chance for lysine to be absorbed synchronously with other amino acids, so as to achieve a balanced complement of amino acids, it can be seen that an appropriate increase in the number of feedings helps increase the binding rate of free amino acids.
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