Diet for determining endogenous amino acid loss in poultry and use thereof

Abstract

This invention relates to the field of poultry feed technology, and more particularly to a diet for determining the loss of endogenous amino acids in poultry and its application. The diet provided by this invention, by mass percentage, comprises 12-14% total amino acids, 17-22% hydrolyzed casein, 16-20% glucose, 18-21.6% amylose, and 30-37.4% amylopectin, wherein the ratio of glucose to starch is 0.30-0.40, and the ratio of amylose to amylopectin is 0.55-0.65. This invention can effectively detect the loss of endogenous amino acids in the ileum of broilers while ensuring normal weight gain and digestive physiological status, thereby improving the accuracy of calculating standard ileal amino acid digestibility, helping to reduce the waste of protein feed resources in broilers, and achieving precision nutrition.

Description

Technical Field

[0001] This invention relates to the field of poultry feed technology, and in particular to a diet for measuring the loss of endogenous amino acids in poultry and its application. Background Technology

[0002] Precision nutrition is a manifestation of refined management in modern animal husbandry and a crucial guarantee for maximizing breeding efficiency. In the poultry feed industry, accurately measuring the amino acid digestibility of feed ingredients is of great significance for implementing precision feed formulation. Although feed formulation based on apparent ileal amino acid digestibility has been widely used for a long time, the apparent ileal amino acid digestibility is easily affected by endogenous amino acids, leading to lower measured values.

[0003] Broiler feed formulations based on standard ileal amino acid digestibility take into account the loss of endogenous amino acids in the ileum, thus more accurately and reasonably reflecting the poultry's ability to digest feed amino acids and reducing nitrogen excretion. Therefore, accurately measuring endogenous nitrogen loss in poultry is of great significance for the precise design of feed formulations, especially for the formulation of low-protein diets.

[0004] Currently, nitrogen-free diets are most widely used to determine basal endogenous amino acid loss due to their simplicity and cost-effectiveness. In this method, animals ingest a diet free of exogenous protein, and the amino acids collected from the ileal digesta are considered to originate from endogenous secretion or loss. However, nitrogen-free diets provided by existing technologies often fail to accurately measure endogenous amino acid loss.

[0005] On the one hand, insufficient energy in nitrogen-free diets leads to a decrease in the activity of intestinal digestive enzymes. On the other hand, excessive starch content in nitrogen-free diets causes starch malabsorption, inhibits feed intake, and affects the digestive physiology of broilers. Since the standard ileal amino acid digestibility represents the state of normal-producing broilers, an ideal method for detecting endogenous amino acid loss needs to be under normal digestive physiological conditions. Therefore, the determination of endogenous amino acid loss in broilers requires a diet that meets the normal digestive physiology of broilers and does not affect the amino acid residue in the broiler intestines. Summary of the Invention

[0006] To address the aforementioned deficiencies, this invention provides a diet for measuring the loss of endogenous amino acids in poultry and its application. The diet provided by this invention enables the measurement of endogenous amino acid loss in broilers under normal digestive physiological conditions.

[0007] The composition and nutrient content of the diet affect the digestive physiology of broilers. Broilers must obtain amino acids from the diet to maintain normal feed intake, body weight, intestinal flora homeostasis, and the secretion of digestive enzymes and mucins, thereby ensuring normal digestive physiology.

[0008] Existing technologies for detecting endogenous amino acid loss in poultry using nitrogen-free diets often fail to meet the animal's needs, leading to alterations in the normal physiological state of intestinal cells and consequently affecting the flow of endogenous amino acids. Even if the amino acid content in the diet is the same as in a normal diet, while meeting the animal's needs and maintaining normal intestinal cell function, the digestion and metabolism of amino acids can affect the accuracy of endogenous amino acid detection.

[0009] Existing research on starch and glucose in diets suggests that different ratios of starch to glucose in the diet can affect the loss of endogenous amino acids, but it does not clarify whether different ratios of starch to glucose affect the digestive physiology of broilers. This invention, for the first time, proposes that the concentration of glucose, the concentration of amylopectin and amylose in the starch, and the protein level in the diet can all affect the digestive physiology of poultry.

[0010] Based on this, in a first aspect, the present invention provides a diet in which, by mass percentage, the total amino acid content is 12-14%, the hydrolyzed casein content is 17-22%, the glucose content is 16-20%, the amylose content is 18-21.6%, and the amylopectin content is 30-37.4%, wherein the ratio of glucose to starch is 0.30-0.40, and the ratio of amylose to amylopectin is 0.55-0.65.

[0011] The diet provided by this invention not only meets the amino acid nutritional needs of broilers, achieves normal digestive enzyme secretion, intestinal mucosal renewal, and maintains the normal physiological level of endogenous nitrogen flow in the entire intestine, but also allows for accurate detection of endogenous amino acid loss in poultry due to the appropriate ratio of glucose to starch, amylose to amylopectin, and amino acid content in the diet.

[0012] In this invention, amino acids are provided by hydrolyzed casein. The hydrolyzed casein used in this invention has a small molecular weight, is easily absorbed, and leaves minimal residue in the intestine. The amino acids (>10 kDa) in the precipitate and residue produced by centrifugation of the ileal chyme are unrelated to hydrolyzed casein and can represent the endogenous amino acid loss of the chyme.

[0013] The diet provided by this invention also includes: cellulose.

[0014] In ordinary diets, since the raw materials used contain substances such as cellulose, there is no need to add extra cellulose to maintain the normal digestive physiology of poultry. However, in the diet provided by this invention, cellulose needs to be added.

[0015] The diet provided by this invention also includes one or more of the following: soybean oil, dicalcium phosphate, limestone powder, sodium chloride, choline chloride, vitamin premix, trace element premix, and titanium dioxide.

[0016] Titanium dioxide is used as an indicator.

[0017] As a preferred embodiment of the present invention, the dietary metabolizable energy provided by the present invention is 3600-3800 kcal / kg, with glucose accounting for 16-20%, amylose accounting for 18-21.6%, and amylopectin accounting for 30-37.4%, wherein the glucose / starch ratio is 0.33, and the amylose / amylose ratio is 0.60. Hydrolyzed casein accounts for 20% of the dietary diet. Furthermore, the vitamin premix and trace element premix are for broiler chickens and can be formulated or purchased commercially.

[0018] The diet provided by this invention, by weight, comprises 17-22% hydrolyzed casein, 16-20% glucose, 30-36% amylose product, 18-23% waxy corn starch, 3-5% cellulose, 2-4% soybean oil, 1-3% dicalcium phosphate, 0.8-1.2% limestone powder, 0.2-0.4% sodium chloride, 0.06-0.1% choline chloride, 0.01-0.03% vitamin premix, 0.1-0.3% trace element premix, and 0.4-0.6% titanium dioxide; the amylose product contains 60% amylose and 40% amylopectin.

[0019] Waxy corn starch contains >98% amylopectin, so it can be considered that waxy corn starch is amylopectin.

[0020] The amylose product used in this invention contains 60% amylose and 40% amylopectin. The advantage of using starch with 60% amylose and 40% amylopectin is that 100% amylose easily forms resistant starch, which is difficult to digest and can easily affect experimental results; moreover, pure amylose is not readily available. Furthermore, the diet of this invention requires amylopectin, and the purchased amylose containing a certain amount of amylopectin can provide amylopectin to the diet.

[0021] In the experimental investigation of this invention, it was finally determined that when the cellulose was sodium carboxymethyl cellulose, the digestive physiological state of poultry after feeding was closest to that of a normal diet.

[0022] Secondly, the present invention provides the application of the above-mentioned diet in maintaining the normal digestive physiological state of poultry.

[0023] The normal digestive physiological state of poultry described in this invention refers to the normal feed intake, body weight, intestinal flora homeostasis, and secretion of digestive enzymes and mucins in poultry.

[0024] Furthermore, the application of the aforementioned diet in enhancing the activity of α-amylase, sucrase, and chymotrypsin in ileal chyme.

[0025] Furthermore, the application of the aforementioned diet in maintaining the normal physiological state of poultry ileal cells, wherein the poultry ileal cells are goblet cells.

[0026] Furthermore, the application of the aforementioned diet in improving the accuracy of detecting endogenous amino acid loss in the ileum of broilers.

[0027] The beneficial effects of this invention are as follows:

[0028] This invention can effectively detect the loss of endogenous amino acids in the ileum of broilers while ensuring that the weight and digestive physiological state of broilers are normal. This improves the accuracy of calculating the standard ileal amino acid digestibility, helps reduce the waste of protein feed resources in broilers, and achieves precision nutrition.

[0029] This invention improves upon traditional nitrogen-free diets by adjusting the ratio of glucose to starch and amylose to amylopectin in the diet, and by adding a specific proportion of hydrolyzed casein, thus obtaining a diet that maintains the normal digestive physiological state of poultry.

[0030] The diet provided by this invention can maintain the normal physiological state of poultry ileal cells. When fed with the diet of this invention, the activities of α-amylase, sucrase, and chymotrypsin in the poultry ileum are consistent with those when fed with a normal diet. Therefore, the diet provided by this invention can accurately detect the loss of endogenous amino acids in the ileum of poultry, especially broilers. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This invention relates to the morphology, intestinal barrier function, and gene expression indicators of the broiler intestine. In the figure, (a) shows AB-PAS staining of goblet cells in the ileum villi. The goblet cells were stained purple by the Alixylene-Periodic Acid-Schiff reaction. The number of goblet cells in eight villi per section was counted and expressed as the average number of stained goblet cells per 100 μm villus length. The scale bar is 20 μm. (b) shows the height of the ileum villi. (c) shows the depth of the ileum crypts. (d) shows the ratio of ileum villi height to crypt depth. (e) shows the D-lactate content in portal vein serum. (f) shows the diamine oxidase content in portal vein serum. (g) shows the endotoxin content in portal vein serum. (h) shows the expression of genes related to cell differentiation. (i) shows the expression of genes related to endoplasmic reticulum stress. Different letters on the bar chart represent significant differences (P < 0.05). Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] In this embodiment of the invention, all components of the diet are available for purchase. The hydrolyzed casein used in this invention was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. (batch number C822594).

[0035] The hydrolyzed casein used in this invention was analyzed by liquid chromatography-tandem mass spectrometry (Shanghai Meiji Biomedical Technology Co., Ltd.) to determine the molecular weight of its peptides. Approximately ≥99% of the peptides had a molecular weight <4000 Da.

[0036] The vitamin premix and trace element premix used in the embodiments of the present invention were purchased from broiler trace element and vitamin production enterprises, and no specific manufacturer is required.

[0037] Example 1

[0038] 1. Experimental design, diet formulation and sample collection

[0039] One hundred and sixty-eight one-day-old AA broiler chickens of similar body condition were randomly divided into four groups, with six replicates per treatment group and seven chickens per replicate. The four treatment groups were a nitrogen-free diet group, a nitrogen-free diet + 10% hydrolyzed casein group, a nitrogen-free diet + 20% hydrolyzed casein group, and a normal broiler diet group as a reference for normal digestive physiology.

[0040] All broiler chickens were fed a basal diet from 1 to 27 days of age, and an experimental diet from 28 to 30 days of age. All experimental diets were pelleted using a feed pelleting machine, and 0.5% titanium dioxide was added as an indicator. The diets contained waxy corn starch (amylose content >98%) and amylose (amylose content 60%, amylopectin content 40%). Hydrolyzed casein was analyzed by liquid chromatography-tandem mass spectrometry (Shanghai Meiji Biomedical Technology Co., Ltd.), and approximately ≥99% of the peptides had a molecular weight <4000 Da, meeting the requirements for enzymatic casein hydrolysis. The composition and nutrient levels of the experimental diets are shown in Table 1. At 31 days of age, the production performance of broiler chickens aged 28–30 days was assessed, and serum, ileal digesta, and ileal tissue samples were collected.

[0041] Table 1. Composition and nutrient levels of feed ingredients

[0042]

[0043]

[0044] Note: 1) Nutrient levels of broiler diet: metabolizable energy 2950 kcal / kg, crude protein 22.50%, Ca 1%, nonphytate phosphorus 0.45%.

[0045] 2. Indicator Measurement

[0046] (1) Growth performance: Chickens were weighed on days 28 and 31 in replicates, and feed intake was recorded for each replicate. Average body weight, average body weight gain and average feed intake were calculated.

[0047] (2) Loss of endogenous amino acids in the ileum: Before analyzing the amino acids in the ileal chyme, the chyme sample was redissolved in physiological saline and fractionated by differential centrifugation. In short, the dissolved chyme was centrifuged at 4°C and 250g for 15 minutes, the supernatant was retained, the precipitate was washed with 10 mL of physiological saline, and then centrifuged at 1450g and 4°C for 30 minutes. The precipitates obtained from both steps were stored at -20°C. The supernatants from both steps were combined and ultrafiltered using an Ultracel-10 regenerated cellulose membrane (molecular weight cutoff filter, 10000 Da; Millipore Co., USA). The precipitate (>10000 Da) from the ultrafiltration step was added to the precipitate obtained from the first two steps, and the mixed precipitate was then freeze-dried for amino acid content analysis. The titanium dioxide content in rice and feed was determined using a spectrophotometer. The digesta and feed were then pretreated according to GB / T18246-2019. Amino acid concentrations were then measured using an amino acid analyzer (A-300, Membrapure, Germany). Ileal endogenous amino acid loss was calculated based on the amino acid flow per kilogram of dry matter intake. All data were calculated on a dry matter basis, using the following formula:

[0048] Loss of endogenous amino acids in the ileum (mg / kg dry matter intake)

[0049]

[0050] (3) Digestive physiological characteristics of broilers

[0051] Digestive enzyme activity: Protein concentration in the mucosa was detected using a BCA protein quantification kit (CW0014, Kangwei Century, China). The activities of α-amylase, sucrase, and chymotrypsin in the digesta were then determined according to the instructions of commercial assay kits (C016-1-1, A082-21, A080-3-1, Nanjing Jiancheng Biotechnology Institute, China).

[0052] Ileum PAS staining: Tissue sections of the ileum and AB-PAS staining were prepared by the company (Seville Biotechnology Co., Ltd., China).

[0053] Serum indicators: A diamine oxidase / lactic acid / bacterial endotoxin joint detection kit (JY-Po-Color-DLT, Beijing中生金域Diagnostic Technology Co., Ltd.) was used.

[0054] Ileum gene expression: Total RNA in the ileum was extracted using an animal tissue / cell total RNA extraction kit (DP451, Beijing Tiangen Biotechnology Co., Ltd., China), and the concentration and purity of each sample were measured at 260 / 280 nm. Then, 1 μg of total RNA was reverse-transcribed into cDNA using the Prime Script TM RTreagent Kit with gDNA Eraser (RR047A, Takara, Japan). Each real-time fluorescence quantitative reaction was carried out using the SYBR Premix ExTaq kit (RR420A, Takara, Japan). Gene-specific primers were synthesized by Sangon Biotech (Shanghai) Co., Ltd., and β-actin was used as an internal reference gene. The relative expression levels of each gene were statistically analyzed by the -ΔΔCt method.

[0055] 3. Data statistics

[0056] Data were analyzed using SPSS version 20.0 (SPSS, IBM, USA). The data distribution was checked by the Shapiro Wilk test. Normally distributed data were compared between groups by one-way ANOVA, and then the Duncan post hoc test was performed. The data are shown as the mean and standard error (SEM). P>0.05 indicates no significant difference, 0.05<P<0.01 indicates a trend of difference, P<0.05 indicates a significant difference, and P<0.01 indicates a highly significant difference.

[0057] 4. Results and analysis

[0058] The basal endogenous amino acid losses of broilers fed a nitrogen-free diet or a diet containing hydrolyzed casein were detected, and the results are shown in Table 2. From the results in Table 2, it can be seen that except for Cys, as the dietary amino acid level increased, the basal endogenous amino acid losses of the remaining 17 amino acids increased significantly (P<0.05), with the highest endogenous amino acid losses in the 20% hydrolyzed casein addition group, followed by the 10% hydrolyzed casein addition group, and the lowest endogenous amino acid losses in the ileum of broilers fed a nitrogen-free diet (P<0.05).

[0059] The above results indicate that the loss of endogenous amino acids in the ileum of broilers is affected by the dietary amino acid content, and the nitrogen-free diet method underestimates the endogenous amino acid loss when broilers normally consume nitrogen-containing diets. Since the basic endogenous amino acids in animals are mainly affected by dry matter intake, and their main components are mucin secreted by goblet cells, intestinal digestive enzymes, and apoptotic cells, the above-mentioned related indicators are used to explain the changes in the loss of basic endogenous amino acids in broilers.

[0060] Table 2. Loss of endogenous amino acids in the ileum of broilers (mg / kg dry matter intake)

[0061]

[0062]

[0063] Note: Different superscript letters for the average data in the same row indicate significant differences (P<0.05).

[0064] Table 3 shows the production performance and digestive enzyme activity of broilers in different diet groups. Broilers fed nitrogen-free diets experienced a significant decrease in body weight, while the addition of 10% and 20% hydrolyzed casein to nitrogen-free diets significantly increased body weight, with the weight gain transitioning from negative to positive values.

[0065] Further analysis revealed that, compared with the nitrogen-free diet group, the activities of α-amylase, sucrase, and chymotrypsin in the ileum were all increased after the addition of 10% and 20% hydrolyzed casein. In particular, the activities of sucrase and chymotrypsin in the nitrogen-free diet with the addition of 20% hydrolyzed casein were not significantly different from those in broilers fed a normal broiler diet, indicating that the addition of 20% hydrolyzed casein is beneficial to maintaining the normal physiological level of digestive enzyme activity.

[0066] Table 3 Production performance and digestive enzyme activity

[0067]

[0068] Note: Different superscript letters for the average data in the same row indicate significant differences (P<0.05).

[0069] After feeding different diet groups, the number of goblet cells in the ileum of broilers was as follows: Figure 1 As shown in Figure a, PAS staining of ileal goblet cells revealed a lower density of purple-stained goblet cells in the nitrogen-free diet group, while the density increased after adding 10% and 20% hydrolyzed casein. However, compared to the control group, the ileal villus height was significantly reduced in the 10% hydrolyzed casein group. Figure 1 (b, P<0.05). Since the number of goblet cells has changed, the secretion of mucin and the barrier function of the mucus layer will also be affected.

[0070] Therefore, the levels of diamine oxidase, D-lactic acid, and bacterial endotoxin in the serum of chicken wings were further examined. Compared with the control group, the serum D-lactic acid levels in the nitrogen-free diet group were significantly lower. Figure 1 e), diamine oxidase ( Figure 1 f), and bacterial endotoxins ( Figure 1 The levels of diamine oxidase (D-lactic acid) in broiler serum were significantly increased (P<0.05), but the levels of D-lactic acid and bacterial endotoxin in broiler serum were significantly lower than those in the nitrogen-free diet group after the addition of 20% hydrolyzed casein (P<0.05), and there was no significant difference compared with the control group (P>0.05). This indicates that the nitrogen-free diet damaged the intestinal barrier function and caused bacterial translocation, which could be effectively improved by the addition of 20% hydrolyzed casein.

[0071] In addition, such as Figure 1 As shown in h, compared with the control group, the expression of Notch-1, a gene related to intestinal stem cell differentiation in broilers, was significantly increased in the nitrogen-free diet group, indicating that intestinal stem cells improved cell stemness and inhibited differentiation into secretory cells. In addition, the expression levels of KLF-4, a transcription factor that regulates terminal differentiation of goblet cells, and Mucin-2, a mucin secretion gene, were significantly decreased in the nitrogen-free diet group. Combined with the results of PAS staining, this indicates that the nitrogen-free diet inhibited the differentiation of goblet cells, thereby affecting the secretion of mucin.

[0072] In addition, since the secretory function of goblet cells is closely related to the endoplasmic reticulum, endoplasmic reticulum stress indicates protein misfolding, which affects mucin secretion and cell viability.

[0073] like Figure 1 As shown in Figure i, compared with the control group, the expression levels of the endoplasmic reticulum stress signaling pathways Grp-78 and ATF-4, as well as the apoptosis gene Caspase-3, were significantly increased in the ileum of broilers fed a nitrogen-free diet (P<0.05). This indicates that endoplasmic reticulum stress occurred in the ileum of broilers fed a nitrogen-free diet, and the ability of intestinal goblet cells to secrete mucin was impaired. This may also be one of the reasons for the decline in intestinal barrier function and the large amount of endotoxin entering the bloodstream. However, after adding 20% ​​hydrolyzed casein to the nitrogen-free diet, the expression of Notch-1, KLF-4, Mucin-2, and Caspase-3 was not significantly different from that in the control group. KLF-4 is a Kruppel-like factor; Grp-78 is glucose-regulated protein-78; and ATF-4 is activated transcription factor-4. The results of this study demonstrate that adding 20% ​​hydrolyzed casein can effectively alleviate the adverse effects caused by NFD.

[0074] The experimental results of Example 1 show that adding 20% ​​hydrolyzed casein to a nitrogen-free diet for broilers can alleviate the decrease in broiler weight and feed intake caused by feeding a nitrogen-free diet alone, as well as the decrease in digestive enzyme activity and goblet cell number. It also helps maintain the normal mucin secretion function of ileal goblet cells and improves the accuracy of endogenous amino acid loss detection.

[0075] Therefore, compared with nitrogen-free diets, the diet of this invention, when fed to broilers, more closely resembles the digestive physiology of broilers with normal digestive physiology. Consequently, the diet provided by this invention allows for the determination of endogenous amino acid loss under normal digestive physiology conditions, providing a more representative measure of endogenous amino acid loss in broilers and achieving precision nutrition.

[0076] Comparative Example 1: Other nitrogen-free diets combined with hydrolyzed casein as a diet

[0077] This comparative study provides the production performance and digestive enzyme activity of broilers when hydrolyzed casein is added to other nitrogen-free diets.

[0078] In this comparative example, the various indicators were tested according to the method in Example 1. The average body weight gain, average feed intake, α-amylase (U / mgprot), sucrase (U / mgprot), and chymotrypsin (U / mgprot) of broilers were the main indicators tested. The results are shown in Table 4.

[0079] The formula for nitrogen-free diet 1 in Table 4 is as follows: glucose 48.88%, corn starch 40%, sodium carboxymethyl cellulose 4%, soybean oil 3%, dicalcium phosphate 1.9%, limestone powder 1%, salt 0.3%, choline chloride 0.2%, vitamin premix 0.02%, trace element premix 0.2%, and titanium dioxide 0.5%.

[0080] The formula for nitrogen-free diet 2 is as follows: glucose 48.88%, amylose 11.12%, amylopectin 28.88%, sodium carboxymethyl cellulose 4%, soybean oil 3%, dicalcium phosphate 1.9%, limestone powder 1%, salt 0.3%, choline chloride 0.2%, vitamin premix 0.02%, trace element premix 0.2%, and titanium dioxide 0.5%.

[0081] Table 4 Production performance and digestive enzyme activity

[0082]

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A diet for determining endogenous amino acid loss in broiler chickens, characterized in that, The hydrolyzed casein accounts for 17-22% by mass percentage, the glucose accounts for 16-20%, the amylose product accounts for 30-36%, the waxy corn starch accounts for 18-23%, the cellulose accounts for 3-5%, the soybean oil accounts for 2-4%, the calcium hydrogen phosphate accounts for 1-3%, the stone powder accounts for 0.8-1.2%, the sodium chloride accounts for 0.2-0.4%, the choline chloride accounts for 0.06-0.1%, the vitamin premix accounts for 0.01-0.03%, the trace element premix accounts for 0.1-0.3%, and the titanium dioxide accounts for 0.4-0.6% in the diet; the amylose content is 60% and the amylopectin content is 40% in the amylose product, wherein the glucose to starch ratio is 0.30-0.40, and the amylose to amylopectin ratio is 0.55-0.65; The cellulose is sodium carboxymethyl cellulose; the amylopectin content in the waxy corn starch is greater than 98%, and 99% of the peptide segment in the hydrolyzed casein has a molecular weight less than 4000 Da.

2. Application of the diet in claim 1 in maintaining the normal digestive physiological state of broilers.

3. Application of the diet in claim 1 in improving the activities of ileum chyme alpha-amylase, sucrase and pepsin of broilers.

4. Application of the diet in claim 1 in maintaining the normal physiological state of ileum cells of broilers, wherein the ileum cells are goblet cells.

5. Application of the diet in claim 1 in improving the detection accuracy of endogenous amino acid loss in the ileum of broilers.

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