The low location lighting is an unique system that allows all evacuation routes to stay illuminated, thereby communicating a clear, continuous and unambigous 'means of escape' message which lead to a safe place. The locations of fire fighting equipment are also clearly marked as part of the system along the escape routes. This reduces possible confusion and panic, factor that hamper the safe egress from occupied areas.
Luminous Lll System,Lll System,Photoluminescent Lll System,Glow In The Dark Lll System JINAN REALGLOW CO.,LTD , https://www.realglowsign.com
The maintenance of metabolism of proteins and amino acids is complex and has been one of the difficulties in animal nutrition research. Maintaining the need as a basic research has an important role in exploring nutrient requirements with universal significance and comparing the nutritional needs of different animals or animals of the same species under different conditions. The article briefly expounds on the significance and ways of maintaining amino acids in poultry amino acids, research methods and research status of maintaining amino acid requirements. Keywords: poultry; proteins; amino acids; maintenance metabolism studies have shown that the amino acid patterns used by animals for maintenance and growth are different, which have different degrees of influence on ideal protein patterns (Fuller et al., 1989). With the in-depth study of the ideal protein model of poultry, scholars at home and abroad pay more and more attention to the research on the maintenance of amino acid metabolic pathways, requirements and models of poultry. The research on maintaining the protein and amino acid nutrition of poultry, the revision of laying standards for laying hens, establishing the ideal protein model of poultry dynamics, better meeting the nutritional needs of poultry, fully exploiting genetic potential, improving the production performance of poultry, and reducing nitrogen The consumption of amino acids and the maintenance of amino acids, the reduction of nitrogen emissions, the conservation of protein raw materials, and the reduction of environmental pollution all have very important significance. 1 Ways to Maintain Metabolism of Poultry Amino Acids Maintenance of amino acid requirements is the minimum amount of amino acids that can balance animals in positive nitrogen (Baker, 1965). Sakomura et al. (1999) defined the requirement of maintaining amino acids as the balance of nitrogen, ie, a dynamic equilibrium in which the nitrogen ingestion amount is equal to the sum of the nitrogen loss and the body nitrogen remains unchanged. The maintenance needs of amino acids in laying hens are summarized nutritively to maintain the normal physiology of laying hens without producing amino acids (Fisher, 1956). Studies have shown that the patterns of amino acids used for maintenance and growth are significantly different. Therefore, total animal requirements must depend on the ratio of maintenance and tissue protein deposition to total requirements (Fuller et al., 1989). The animal always meets its nutritional needs first to ensure the normal physiological metabolism of the body, and methionine is the first limiting amino acid in poultry, mainly due to the relatively high maintenance requirement for methionine in poultry. The nitrogen used by poultry for maintenance is finally metabolized by metabolically manure nitrogen, endogenous urinary nitrogen, and body surface nitrogen. Metabolic fecal nitrogen mainly includes saliva, digestive enzymes, and nitrogen contained in cells that are shed in the digestive tract. Endogenous urine nitrogen mainly refers to the nitrogen necessary for the net catabolism of the minimal body protein in the urine during life-sustaining. The body protein is in the dynamic equilibrium of decomposition and synthesis. Some of the decomposed amino acids are recombined with the body protein, and the other part is oxidized and decomposed to produce urea or uric acid which is excreted in the urine. This part is the net catabolism of the body protein. Nitrogen losses on the surface include hair, hooves, feathers, and skin lost nitrogen. Feather and skin renewal require very little protein and are generally negligible. The maintenance metabolism of amino acids is mainly involved in the renewal of body proteins, protein synthesis of normal loss of animal skin, feathers, and intestinal epithelial shedding, followed by conversion of hormones, enzymes, vitamins, and other biologically active substances. Moreover, amino acid substitutions are also available. Used for certain amino acid consumption, such as cystine can replace 20% of methionine for maintenance needs; tyrosine can replace 50% of phenylalanine for maintenance needs (Leveille et al., 1960). The amino acids used for poultry maintenance need to mainly consider the amino acid losses caused by the excretion of endogenous nitrogen, including nitrogen excretion in the form of amino acids, nitrogen excretion in the form of non-amino acids, and nitrogen excretion in the form of creatinine; skin coverings such as feathers and dander are caused by shedding. Surface amino acid loss. Hurwitz et al. (1983) classified amino acid loss into the intestinal loss mainly in the digestive tract excretion fluid and mucosal epithelium shedding when studying the amino acid maintenance needs of turkeys; surface loss mainly due to feather and dander shedding; Acid anhydride-induced loss of methionine, glycine, and arginine. It assumes that in addition to several kinds of special irreversible amino acid metabolism (such as proline hydroxylation, histidine methylation, etc.), tissue renewal does not cause any net amino acid loss. However, different turnover rates of amino acids are different in the turnover process of body proteins. The utilization of different amino acids in anabolism is also different. As the activities of the enzymes involved in amino acid metabolism are different, some amino acids are oxidatively decomposed and eventually excreted in the form of urine nitrogen. . He Jianhua et al. (1996) reported that the following amino acid net loss was considered when studying the need for maintenance of amino acids in adult ducks: loss of intestinal tract, dander loss, loss of glycine, arginine, and methionine due to creatine creatinine excretion. (1 mol of glycine, arginine, and methionine are each consumed to form 1 mol of creatine creatinine). It is assumed that the body weight of the adult male duck does not change when it feeds on low-nitrogen diets, that is, it is in a maintained state, and the loss of excrement nitrogen when eating nitrogen-free diets is the loss of endogenous nitrogen. Low-nitrogen diets were used to determine the total amount of creatine creatinine excretion and nitrogen loss from dander. The mode of maintenance of amino acids in meat ducks is based on the ratio of endogenous nitrogen excretion to nitrogen loss from dander shedding, the amino acid pattern of endogenous amino acids and dander in adult ducks (assuming the same pattern as feathers) and creatine. The loss of creatinine, arginine, and methionine from creatinine was determined. Moughan (2002) believes that animal nitrogen metabolism loss includes: loss of skin surface nitrogen loss caused by loss of skin cover; loss of urinary nitrogen to reflect the ineffectiveness of body protein turnover; loss of nitrogen caused by intestinal mucosa, cell loss and bile, digestive enzyme secretion Loss caused by mandatory synthesis of essential non-proteinaceous nitrogenous substances; Loss caused by irreversible changes in amino acid chemistry (eg lysine to hydroxyl lysine); Loss of free amino acids in urine; Proportion of the last 3 losses Smaller, therefore, usually ignored when assessing animal protein and amino acid needs. Li et al. (2003) used the amino acid composition of fecal urine excretion as the amino acid composition of urine nitrogen when studying the amino acid requirement of Taihe Silky Fowl, but the amino acids in fecal urine excretion were mainly derived from digestive tract secretions and Shedding mucosa and epithelium; 80% of the amino acids involved in the synthesis of proteins in body protein turnover are derived from the degradation of body tissue proteins. The loss of endogenous nitrogen is the single most important factor for nitrogen maintenance needs (Nyachoti et al., 1997). 2 Methods for Maintaining Poultry Amino Acid Maintenance Needs The maintenance of poultry amino acids needs to be more difficult to determine, and the methods used by various scholars are not the same (Smith, 1978; Hurwitz et al., 1983). 2.1 Nitrogen balance method The initial study on the need for amino acid maintenance was carried out by Professor Rose of the University of Illinois on the need for human maintenance and nitrogen balance. The nitrogen balance method is based on the difference between ingested nitrogen and nitrogen excreted through feces and urine. The minimum maintenance requirement is the amount of amino acids that can maintain the animal's zero nitrogen balance. Because the nitrogen balance method has many inherent problems, such as feed waste, and it is impossible to guarantee complete collection of fecal material, the results measured by Rose and his researchers are considered to be low (Yong and Pellett, 1991; Fuller and Garlick, 1994). Many scholars subsequently adopted this method for the study of poultry maintenance needs (Leveille and Fisher, 1958, 1959, 1960; Leveille et al., 1960). Ishibashi (1973) and Burnham et al. (1992) also used nitrogen balance tests on adult cocks to determine the isoleucine maintenance requirement in chickens. Kim et al. (1997a,b,c) used nitrogen balance methods to determine the amino acid maintenance needs of growing chickens. Hruby et al. (1998) used nitrogen balance tests on broiler breeds, but the results all indicated that lysine maintenance needs could not be measured. 2.2 Mathematical model studies have shown that the maintenance requirements for amino acids can be obtained through mathematical models. This is a more classical method of mathematical speculation. Shin et al. (1990) applied the mathematics model to divide the methionine requirement into a maintenance-need part based on metabolic body weight and a growth requirement part based on body weight gain or nitrogen weight gain, and the formula is: I=1/a(R-BW0.75) Medium: I - amino acid intake; R - dependent variable; BW 0.75 - maintenance requirement per kilogram of metabolic body weight; 1/a - weight gain per gram or weight gain per milligram of nitrogen. Many scholars have applied this mathematical model to determine the amino acid requirements of various animals (Yang et al., 1997a,b,c). Kim et al. (1997) believe that this model is more practical for determining the maintenance and growth of a single amino acid in broiler chickens. However, it is difficult to determine amino acids in hens. McDonald et al. (1985) used a reading model to synthesize various published data to propose the need for amino acid maintenance. Since these models are static and cannot be changed with the nutritional needs and environmental changes of laying hens, and these models do not take into account the digestibility of amino acids, it is believed that the ingested amino acids are used to maintain the same efficiency as protein synthesis, etc. Problems have limited the application of these models, but the proposed models have played an important role in the research of poultry's amino acid nutritional needs. 2.3 isotope labeling method isotope labeling method for the determination of amino acid maintenance needs of the principle is to determine the oxidation of L-[1-14C] phenylalanine as dietary protein or amino acid content increases. Ball and Bayley (1986) studied the effect of changes in dietary protein levels on phenylalanine oxidation in piglets, feeding piglets diets containing a certain concentration of intact protein (skim milk), different free amino acid concentrations, or feeding Diets containing a certain amount of free amino acids and different skimmed milk content, when the weight of the pig reached 2.5 kg, the amount of 14 CO2 consumed was determined in addition to the measurement of radioactive substances in the liver. The results showed that the decomposition of [14C]phenylalanine decreased linearly as the dietary nitrogen content increased from 19.2 g/kg to 38.4 g/kg, while the nitrogen content continued to increase to 49.2 g/kg. There is no effect. When the dietary protein content was increased from 160 g/kg to 280 g/kg by adding dried skim milk, the reduction in phenylalanine degradation was also observed, but considering this method has poor operability, high measurement costs, and environmental Having a certain influence, as well as the existing technological conditions, have limited the use of this method. 2.4 Amino acid gradient diets use diets formulated as a gradient diet in the absence of the state. Baker et al. (1996) proposed another method to determine the need to maintain amino acids - the amino acid gradient diet method. That is, broilers are fed diets with 5% to 95% of the different proline levels that meet the requirements for maximum growth performance, and then use the amount of proline deposited for proline. The amount of ingested food and protein deposition were subjected to regression analysis. The intercept value of the Y axis was the valine maintenance requirement obtained by two different methods. Edwards et al. (1997) also used a threonine gradient diet (5% to 95% of the threonine requirement for maximum performance) to study the growth requirement for threonine in growing chickens. At present, the amino acid gradient diet method is considered to be a better method for determining the maintenance of amino acids in poultry. 2.5 Factorial approach He Jianhua et al. (1996) believe that the use of factorial methods to estimate the amino acid requirements of growing animals is based on the following two hypotheses: 1 The amino acid requirement is mainly composed of maintenance needs and growth needs; 2 different The growth of animals of both age and weight gains only a quantitative increase in protein deposition, while the amino acid patterns of the constituent proteins do not change, ie the amino acids used for growth need to be estimated from the quantity and quality of the deposited proteins. Based on the above hypothesis, the amino acid requirement for maintenance (MAA) is established when the amino acid requirement pattern of the mallard duck is established. The following formula is used: MAA=PRMAAm+C where: PRM=ABW2/3PRM is the protein requirement for maintenance; AAm The amino acid pattern used for maintenance; C is the loss of methionine, arginine, and glycine due to creatine and creatinine excretion; A is the coefficient needed to maintain the protein; BW is body weight. Although the methods used by He Jianhua's experiment are reliable, they are still controversial (Simon, 1960). Yin Qingqiang (1995) used the factorial method to determine the amount and pattern of digestible amino acid maintenance in laying hens. 2.6 Dose Response Test Dose response test is also a method for determining the need for amino acid maintenance (Fisher and Morris, 1970). The amino acid ingestion quantity is regressed using the growth performance index as a variable. The intercept of the Y axis is valine. Maintain demand. Owens et al. (1985) conducted dose-response experiments on growing chickens. The results showed that the maintenance iseucine requirement per kg body weight of growing chickens was 203 mg/d. 3 Research Progress on Maintaining Needs for Poultry Amino Acids Maintenance of essential amino acids in poultry requires the study of amino acid needs and ideal protein patterns. Initially some scholars often ignored the need to maintain the need for overall needs, which is unreasonable and unscientific (Moughan, 1988). Block et al. (1985) reported that the method for estimating amino acids proposed by using only eggs and amino acids constitutes a neglected requirement for the maintenance of amino acids. Leveille et al. (1960) found that the maintained amino acid requirement pattern is highly related to the amino acid composition pattern of chicken feathers. It is recommended to use the layered amino acid pattern of laying hens as a maintenance-required mode, but due to the high proportion of cystine in feathers, especially For chickens fed a corn-soybean meal diet, methionine is the first limiting amino acid, and the ratio of methionine to cystine is very important. Therefore, the pattern of amino acids in feathers is used instead of maintaining the required amino acid composition pattern. The credibility is not high and has certain limitations. Fisher et al. (1983) and McDonald et al. (1985) proposed to use the maintenance amino acid requirement model of adult cocks instead of laying hens to maintain the required model. The available data are also mostly test results for adult cocks, but due to male and female chickens. There is a certain difference between the physiological metabolism and the basal metabolic rate. Therefore, such replacement will lead to greater errors. Michell (1962) found that females need 10% lower amino acid maintenance than males. Studies have shown that the maintenance, growth, and amino acid requirements and patterns of the three parts of the egg (flesh or milk) are different (Fuller, 1989) and have different degrees of influence on the ideal protein model. Hurwitz et al. (1973) thought that the maintenance of amino acids in laying hens needs about 25% of the total needs; Hu Dixian (1985) believes that the maintenance of amino acids in laying hens needs about 15% to 30% of the overall needs; Yin Qingqiang (1995) believes that The maintenance needs of amino acids in laying hens accounted for 18%~25% of the overall needs, which is higher than the 4.2% of the total needs of pigs. The amino acid requirement and the ideal protein model during the laying period of laying hens have high dynamics. Changes in laying hens' egg production levels or maintenance requirements will inevitably bring about changes in the ratio of their egg production needs to their maintenance needs. Changes in the ideal protein pattern of laying hens under different production performance conditions. Therefore, it is of great significance to study the requirement and pattern of maintaining amino acids in laying hens. The maintenance of amino acid in chickens requires basic metabolism from various organs and tissues of the body. During the egg protein synthesis process of eggs, there is also the consumption of non-productive amino acids, which also belong to the part of amino acids. However, due to the different amounts of protein in tissues and organs of various parts of the body, even if the amount of protein is the same, the metabolic intensity of protein (or amino acid) is also different. Therefore, the proportion of amino acids required for the maintenance of each part of tissues and organs is very different. However, for the time being, the estimate of chicken amino acid maintenance needs is also an estimate of the chicken's overall average value. In the growth phase, the proportion of maintenance needs in the total amino acid requirement is small, but as the age increases, the proportion increases (Li et al., 2003). The body weight, egg production performance, and weight gain vary greatly among different layer breeds, and there are differences in the amino acid requirements for maintenance, egg production, and weight gain. The available data indicate that the determination of the amino acid maintenance needs of broiler chickens and roosters is based on the body weight or metabolic weight of the birds. However, for animals, maintaining body fat reserves does not consume amino acids, and maintenance needs should be expressed as a requirement for body protein gain. Therefore, the use of adult roosters to determine amino acid maintenance needs to largely avoid The errors caused by large changes in egg production and body fat and difficulties in determination. Some scholars believe that the maintenance of chicken amino acid needs to be related to the amount of body protein (non-feathers) of chickens rather than the weight of chickens, that is, the animal needs to maintain amino acids and its body protein content is more relevant (Baker et al., 1996 Edwards et al., 1997). Fuller (1994) showed that the lysine maintenance requirement obtained by the nitrogen balance method is lower than that obtained by Batterham et al. (1990) based on the measurement of total protein and amino acid deposition, respectively. The lysine maintenance requirement obtained when the deposition of the amino acid was used as the reaction variable was 50% higher than the requirement of using the zero protein deposition as the variable. The existing data on the maintenance of amino acids are mostly based on the total amino acid requirement, while ignoring the influence of endogenous amino acid metabolism on maintenance needs, making the results lack of comparability. Studies have shown that the determination of endogenous amino acid metabolism and maintenance of amino acid needs and models can not be ignored. De lange et al. (1995) believe that the loss of endogenous nitrogen is the largest proportion of the nitrogen requirement in livestock and poultry. Therefore, it is more practical to determine the available amino acids to maintain the needs and patterns. There are many factors that affect the maintenance needs of the animal's amino acids and the entire ideal protein model, such as genetic type (variety), environment and other nutrients. Edwards (1999) showed that differences in broiler breeds resulted in differences in protein deposition ability. For the same fat accumulation rate of broilers of the same sex and breed, the higher the protein deposition rate, the higher the requirement for essential amino acids. It is also the reason that meat cocks need higher amino acids than meat hens, that is, gender differences affect the amino acid requirement of broilers (Han and Baker, 1991, 1993, 1994). Baker (1995) believes that genetics, gender, variable criteria for the basis, dietary energy concentration, and statistical methods all affect the lysine requirement of pigs; at the same time, the stocking density, ambient temperature, and disease stress also have an impact. Its demand, these external conditions also affect the test method itself. Kim et al. (1997) reported that dietary nutrient composition, age, sex, production potential, physiological status, and environmental conditions influence the growth and maintenance needs of methionine, thereby affecting the maximum growth performance and feed intake of poultry. Yin Qingqiang (1995) showed that as the egg production of laying hens increases, the proportion of each essential amino acid requirement for maintenance needs is relatively low, which is of great significance in guiding production practice. Maintaining nutritional needs, whether in absolute or relative terms, is not fixed, but increases or decreases with many factors, such as environmental temperature, stocking density, and disease stress. The difference in gender also affects the amino acid requirement of broilers (Baker, 1994). 4 Summing up the research needed to maintain amino acids is an important part of poultry protein and amino acid nutrition. Relative to pigs, the maintenance of metabolic and nutritional needs of poultry amino acids is even more important. The research on the maintenance needs of amino acids in different poultry or different species under the same conditions has very important significance in determining the amino acid requirement and ideal protein model of poultry, saving protein raw materials and reducing environmental pollution. However, due to the complexity of maintaining amino acid metabolism, it has brought great difficulties to the study of the maintenance needs of amino acids in poultry. Domestic and foreign scholars have relatively little research work in this area. However, in view of the current tight market for protein raw materials, poultry Farming tends to be more scaled. It is very urgent and necessary to study the amino acid digestibility of feedstuffs, the maintenance of essential amino acids in poultry, and the utilization efficiency of protein deposition in transformed body. Therefore, the discussion and research on the maintenance of metabolic pathways, nutritional needs, and ideal protein patterns in poultry are still in-depth and need to be further developed. This will provide reference for determining the amino acid requirement of poultry and the rational application of the ideal protein model under current culture conditions. .