Method for increasing hatched weight of chicks and promoting early growth and development and application

Abstract

The invention belongs to the technical field of poultry early nutrition in the livestock breeding industry, and relates to a method for increasing the hatched weight of chicks and promoting early growth and development and application of the method. Through observation of indexes such as hatching time, hatching performance, growth performance, organ indexes, transport and absorption of nutrient substances in yolk sacs, blood biochemistry and the like, the hatching time of chicks is advanced after TCA is added into embryo eggs, the hatching time is shortened, the embryo weight of the chicks when the chicks are E16 and the weight of the hatched chicks are remarkably increased, and the survival rate of the chicks is increased. The growth of the broiler chickens is remarkably promoted in the feeding period after hatching, and the leg muscle yield is remarkably increased. In addition, TCA is added into the embryo egg, and the transport of lipid in YSC to YSM is accelerated by up-regulating expression of E16YSM and lipid transport related genes. Results show that the effect of adding taurocholic acid into the embryo eggs to promote the growth of broiler chickens and laying hens in the hatching period and the growth of hatched broiler chickens is exact and reliable.

Description

Technical Field

[0001] The invention belongs to the technical field of early poultry nutrition in animal husbandry, and relates to a method and application for increasing the hatching weight of chicks and promoting early growth and development. Background Art

[0002] Since the 1950s, the age of broilers at slaughter has decreased by about 40% and the slaughter weight has more than doubled. In broiler production, the incubation period accounts for about one-third of the entire life cycle. Disturbances during embryonic development can affect the entire production cycle and cause irreversible losses to broiler producers, so the importance of the incubation period has increased. The chicken embryo is completely dependent on the nutrients in the egg, mainly water, lipids and proteins. During the first week of incubation, glucose reserves are used to maintain metabolism. As the embryo develops and the chorioallantoic membrane is formed, lipids become the main energy source. After hatching, the chick must quickly adapt from using egg nutrition to an exogenous diet of protein and carbohydrates. In addition, the chick is usually fasted for 48 hours after hatching until it is sent to the farm. Delayed feed access can lead to problems such as increased mortality and developmental delays. In-egg access is an alternative to provide essential nutrients to the chick embryo during this critical and challenging period. By providing nutrients during embryonic development, the negative effects of post-hatching fasting and transition periods are minimized, thereby ensuring maximum expression of genetic potential throughout the production cycle. The improved nutritional status and physiological changes following the addition of embryonated eggs can resonate throughout the entire rearing period, resulting in significant health and economic benefits.

[0003] In the prior art, for example, the patent with publication number CN 107173262 A discloses a method for adding bile acid into embryonated eggs to promote the growth of hatched chicks. The bile acid solution is directly injected into embryonated eggs hatched to 3 embryonated ages, which can significantly promote the muscle development of chicken embryos and the growth of chickens after hatching. However, the bile acid used is a mixed acid, and it is not proved which bile acid is specifically effective. Moreover, it is dissolved with DMSO (dimethyl sulfoxide, a sulfur-containing organic compound) and diluted with PBS, which has a great stimulation on embryonic development and affects the hatching rate. At the same time, it is injected into embryonated eggs of 3 embryonated ages, and the air chamber of embryonated eggs of 0 to 4 embryonated ages is too small, the injection volume is limited, and further hatching of embryonated eggs is affected. In addition, there are some mixed nutrients composed of β-hydroxy-β-methylbutyric acid, N-carbamyl-L-glutamic acid or glutamine, taurine, and γ-aminobutyric acid in embryonated eggs, but these nutrients have limited ability to increase the weight of chicks after hatching and promote early growth and development, and it is difficult to meet the needs of the chicken farming industry for increasing production and increasing breeding benefits. Summary of the invention

[0004] The purpose of the present invention is to provide a method and application for increasing the hatching weight of chicks and promoting early growth and development, which promotes the development of chicken embryos by adding taurocholic acid to embryonated eggs, promotes the absorption and utilization of yolk lipids, increases the hatching weight of chicks, and improves the growth performance and feed conversion efficiency of broiler chickens during the breeding period.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] In a first aspect, the present invention provides a method for increasing the hatching weight of chicks and promoting early growth and development, wherein a taurocholic acid solution is added into the air chamber of a chicken embryo.

[0007] The inventors have found in animal experiments that bile acid can effectively improve fat absorption and increase egg production by promoting pancreatic lipase activity in laying hens fed a high-fat diet. The primary free bile acid synthesized in the liver is connected to taurine to form taurine-conjugated bile acid. The main source of nutrition during the development of chicken embryos is lipids in the yolk sac. Bile acids can reduce the surface tension of fat and water phases, thereby promoting the digestion, absorption and transport of lipids. Therefore, it is of great significance to take measures during the incubation period to enable chicken embryos to better absorb and utilize yolk lipids, thereby increasing the weight of chicks and their growth after hatching. Taurocholic acid (TCA), as one of the most abundant conjugated bile acids in broiler serum, liver and intestines, plays an important role in lipid absorption and transport. TCA can promote the absorption of lipids in the digestive tract.

[0008] In some other embodiments, the taurocholic acid solution is a sterile saline solution of taurocholic acid.

[0009] In some other embodiments, the concentration of the taurocholic acid solution is 5-25 mg / mL; preferably, the concentration of the taurocholic acid solution is 12.5 mg / mL.

[0010] In some other embodiments, the amount of the taurocholic acid solution added is 0.1-0.5 mL; preferably, the amount of the taurocholic acid solution added is 0.2 mL.

[0011] In some other embodiments, the chicken embryo is a chicken embryo hatched to 9-11 embryonic ages; preferably, the chicken embryo is a chicken embryo hatched to 11 embryonic ages.

[0012] The inventors found in the research process that the air chamber of chicken embryos at 0 to 4 embryonic ages is too small, the injection volume is limited and will affect the further hatching of the embryo eggs; as the embryo develops, injection into the air chamber after 15 embryonic ages will reduce the effect due to the weakening of osmotic effect. Therefore, the time of air chamber injection is generally between 5 and 14 days of incubation. The present invention found through research on the appropriate injection time that injecting taurocholic acid into the air chamber at 11 embryonic ages has a low mortality rate for chicken embryos and the most significant effect.

[0013] In some other embodiments, the taurocholic acid solution is further sterilized by filtration before being added; preferably, the filtration sterilization is performed using a 0.22 μm sterile filter.

[0014] In a second aspect, the present invention provides a use of taurocholic acid in increasing the hatching weight of chicks and promoting early growth and development.

[0015] In some other embodiments, the increasing the hatching weight of chicks and promoting early growth and development are to shorten the hatching time, improve hatching performance, improve growth performance, improve organ index, improve the transport and absorption of nutrients in the yolk sac or reduce blood lipid levels.

[0016] In a third aspect, the present invention provides a method for increasing the hatching weight of chicks and promoting early growth and development by using taurocholic acid, wherein the method for increasing the hatching weight of chicks and promoting early growth and development as described in the first aspect is used, and taurocholic acid is added to the air chamber of the chicken embryo.

[0017] In a fourth aspect, the present invention provides a use of taurocholic acid in the preparation of a product for increasing the hatching weight of chicks and promoting early growth and development.

[0018] Beneficial effects of the present invention:

[0019] (1) In the process of hatching embryonated eggs, the present invention adds taurocholic acid (TCA) solution to the air chamber of the chicken embryo, and observes the hatching time, hatching performance, growth performance, organ index, transport and absorption of nutrients in the yolk sac, and blood biochemistry, etc. It is found that after adding TCA to the embryonated eggs, the hatching time of the chicks is advanced, the hatching time is shortened, the embryo weight at E16 and the weight of the chicks after hatching are significantly increased, and the growth of broilers is significantly promoted during the feeding period after hatching, and the leg muscle production is significantly increased. In addition, the addition of TCA to the embryonated eggs accelerates the transport of lipids from YSC to YSM by upregulating the expression of genes related to E16 YSM and lipid transport. The above results all show that the effect of adding taurocholic acid to embryonated eggs to promote the growth of broilers and laying hens during the hatching period and the growth of broilers after hatching is accurate and reliable.

[0020] (2) The taurocholic acid (TCA) solution proposed by the present invention is added to the air chamber of the embryo egg, which has little stimulation on the development of the chicken embryo, is easy to operate, and has high efficiency, and is suitable for large-scale utilization in production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] Figure 1 This is the operation process of adding taurocholic acid to embryonated eggs in the embodiment of the present invention; wherein Figure 1 (1) is the tool used for embryo egg injection. Figure 1 (2) is a small electric drill that drills holes at the end of the air chamber. Figure 1 The middle (3) is the small hole drilled at the end of the air chamber. Figure 1 (4) shows the insertion of a sterile syringe into the drilled hole and the depth of insertion. Figure 1 (5) is the process of slowly injecting taurocholic acid into the embryo egg air chamber. Figure 1 Middle (6) is the egg hole sealed with paraffin;

[0023] Figure 2 The effects of adding different doses of taurocholic acid to embryonated eggs of different embryonic ages on hatching rate, yolk sac specific gravity and chick weight in the embodiments of the present invention are shown; Figure 2 (A) is the hatching rate, Figure 2 Middle (B) is the specific gravity of E16 yolk sac, Figure 2 Middle (C) is the specific gravity of the yolk sac at D0, Figure 2 Middle (D) is the weight of E16 chicken embryo. Figure 2 Middle (E) is the weight of chicks at D0, data are expressed as Mean±SD (n=8), *P<0.05;

[0024] Figure 3 The effect of adding taurocholic acid to embryonated eggs on the hatching time of Hy-Line brown laying hens and AA broilers in the examples of the present invention; wherein Figure 3 The middle (A) is a Hy-Line brown laying hen; Figure 3 Middle (B) is AA broiler;

[0025] Figure 4 The effect of adding taurocholic acid to embryonated eggs on the lipid content of yolk sac membrane (YSM) and yolk sac contents (YSC) of Hy-Line Brown laying hens in the examples of the present invention is shown; Figure 4 (A) is triglyceride (TG), Figure 4 (B) is free fatty acid (NEFA), Figure 4 (C) is glycerol. Figure 4 The middle (D) is total cholesterol (TCH), Figure 4 The middle (E) is free cholesterol (FCH), Figure 4 Middle (F) is cholesterol ester (CE); data are expressed as Mean±SD (n=8), *P<0.05;

[0026] Figure 5 The effect of adding taurocholic acid to embryonated eggs on the lipid content of yolk sac membrane (YSM) and yolk sac contents (YSC) of AA broiler chickens in the examples of the present invention; wherein Figure 5 (A) is triglyceride (TG), Figure 5 (B) is free fatty acid (NEFA), Figure 5(C) is glycerol. Figure 5 (D) is total cholesterol (TCH), Figure 5 (E) is free cholesterol (FCH), Figure 5 Middle (F) is cholesterol ester (CE), data are expressed as Mean±SD (n=8), *P<0.05, **P<0.05;

[0027] Figure 6 The effect of adding taurocholic acid to embryonated eggs on the expression of genes related to lipid transport in E16 yolk sac membrane (YSM) in the embodiments of the present invention; Figure 6 The middle (A) is a Hy-Line brown laying hen. Figure 6 Middle (B) is AA broiler chicken, data are expressed as Mean±SD (n=8), *P<0.05, **P<0.001;

[0028] Figure 7 The effect of adding taurocholic acid to embryonated eggs on the growth performance of AA broiler chickens after hatching in the embodiment of the present invention; Figure 7 (A) is the average weight, Figure 7 Middle (B) is the average daily weight gain, Figure 7 (C) is the average daily feed intake. Figure 7 Middle (D) is feed weight ratio, data are expressed as Mean±SEM (n=6), *TCA group is significantly different from NC group P<0.05, *TCA group is significantly different from PC group P<0.05;

[0029] Figure 8 The effect of adding taurocholic acid to embryonated eggs on the organ index of AA broiler chickens after hatching in the embodiment of the present invention;

[0030] in Figure 8 (A) is the liver index, Figure 8 Middle (B) is the chest muscle index, Figure 8 Middle (C) is the leg muscle index, data are expressed as Mean±SD (n=6), *P<0.05;

[0031] Fig. 9 The effect of adding taurocholic acid to embryonated eggs on the mRNA level of leg muscle proliferation and differentiation-related regulatory factors in the embodiments of the present invention; Fig. 9 Where (A) is D0, Fig. 9 (B) is D21, where Fig. 9 Middle (C) is D42, data are expressed as Mean±SD (n=6), *P<0.05, **P<0.001, ***P<0.0001. DETAILED DESCRIPTION

[0032] Example 1

[0033] (1) Method for adding taurocholic acid into the air chamber of embryonated eggs

[0034] The steps for adding taurocholic acid to the air chamber of embryonated eggs are as follows: Figure 1 As shown: At the 11th embryonic age of the embryonic egg incubation, the air chamber insertion position is determined by egg lighting and transferred to a clean bench. The embryonic egg insertion position is disinfected with 75% alcohol, and a small electric drill is used to drill a small hole with a diameter of about 1 mm at the end of the air chamber (drill diameter: 1 mm) ( Figure 1 Use a 1 mL sterile injector to insert the needle into the drilled hole to a depth of about 0.5 cm ( Figure 1 In step (4)), taurocholic acid is slowly injected into the air chamber of the embryo egg at a dosage of 0.2 mL ( Figure 1 After the addition is complete, immediately seal the egg hole with paraffin wax ( Figure 1 Step (6)), and transfer to an incubator for incubation according to normal incubation procedures. The incubation procedures are: 1-3 embryos: temperature 38.0°C, relative humidity 60-75%; 4-18 embryos: temperature 37.8°C, relative humidity 50-65%; 19-21 embryos: temperature 37.3°C, relative humidity 65-75%.

[0035] Example 2

[0036] Study on the appropriate time and dosage of adding taurocholic acid into embryonated eggs

[0037] The experiment selected 180 fertilized eggs of similar weight (egg weight 55-65g, average egg weight 60.8g) for hatching, and the embryo egg addition test was carried out at the 9th embryonic age (E9) and the 11th embryonic age (E11) of hatching, and the embryo egg addition operation was carried out according to the method described in Example 1. Each treatment group had 20 chicken embryos, and the experimental treatments were respectively:

[0038] (I) Negative control group (NC): no treatment was added;

[0039] (II) Positive control (PC): add 0.2 mL of physiological saline solution;

[0040] (III) 1 mg TCA: add 0.2 mL of 5.0 mg / mL TCA;

[0041] (IV) 2.5 mg TCA: add 0.2 mL of 12.5 mg / mL TCA;

[0042] (V) 5 mg TCA: add 0.2 mL of 25 mg / mL TCA.

[0043] At the 16th embryonic age (E16) of chicken embryo incubation, each group selected eggs with similar egg weight, separated the yolk sac and liver, weighed and calculated the organ index. On the day of hatching (D0), each group selected chicks with a weight close to the average weight of the group, counted the weight, killed the chicks by neck dislocation, separated the yolk sac and liver, weighed and calculated the organ index. Organ index = organ weight / live weight × 100%.

[0044] Example 3

[0045] Experimental study on the effect of adding taurocholic acid into the air chamber of embryonated eggs to increase the weight of laying hens

[0046] The experiment selected 300 Hy-Line Brown commercial fertilized eggs of similar weight for incubation (egg weight 50-60g, average egg weight 57.6g), randomly divided into 3 groups, and carried out embryo egg addition test on the 11th day of incubation period, and the experimental treatments were as follows: negative control group: no treatment; positive control group: adding 0.2mL of physiological saline; taurocholic acid (TCA) group: adding 0.2mL of 12.5mg / mL taurocholic acid solution to the air chamber. The embryo egg addition method and incubation procedure are the same as in Example 1.

[0047] At E16 of chicken embryo incubation, each group selected eggs with similar egg weight, separated yolk sac, liver, breast muscle and leg muscle, weighed and calculated organ index. At D0, each group selected chicks with a weight close to the average weight of the group, counted the weight, killed the laying hens by neck dislocation, separated yolk sac, liver, breast muscle and leg muscle, weighed and calculated organ index. Organ index = organ weight / live weight × 100%. Collect yolk sac content (YSC) and yolk sac membrane (YSM) tissue samples, put them into 2mL cryopreservation tubes, put them in liquid nitrogen for quick freezing, and store them at -80℃ for testing.

[0048] Example 4

[0049] Experimental study on the effect of adding taurocholic acid into the air chamber of embryonated eggs to increase the weight of broilers out of the shell

[0050] The experiment selected 240 AA commercial fertilized eggs of similar weight for incubation (egg weight 50-60g, average egg weight 55.0g), randomly divided into 3 groups, each group 6 replicates, and carried out embryo egg addition test on the 11th day of incubation period, and the experimental treatments were as follows: negative control group: no treatment; positive control group: adding 0.2mL of physiological saline; taurocholic acid (TCA) group: adding 0.2mL of 12.5mg / mL taurocholic acid solution to the air chamber. The embryo egg addition method and incubation procedure are the same as in Example 1.

[0051] At the 16th embryonic age (E16) of chicken embryo incubation, each group selected eggs with similar egg weight, separated the yolk sac, liver, breast muscle and leg muscle, weighed and calculated the organ index. On the day of hatching (D0), each group selected chicks with a weight close to the average weight of the group, counted the weight, killed the broilers by neck dislocation, separated the yolk sac, liver, breast muscle and leg muscle, weighed and calculated the organ index. Organ index = organ weight / live weight × 100%. Collect yolk sac content (YSC) and yolk sac membrane (YSM) tissue samples, put them into 2mL cryopreservation tubes, put them in liquid nitrogen for quick freezing, and store them at -80℃ for testing.

[0052] Example 5

[0053] Experimental study on the effect of adding taurocholic acid to embryonated eggs to promote early growth of broiler chickens after hatching

[0054] 1. Animal Experiment Design

[0055] The experiment selected 540 AA commercial generation fertilized eggs of similar weight for hatching (egg weight 50-60g, average egg weight 55.1g), randomly divided into 3 groups, each group 6 replicates, and carried out embryo egg addition test on the 11th day of the incubation period, and the experimental treatments were: negative control group: no treatment; positive control group: adding 0.2mL of physiological saline; taurocholic acid (TCA) group: adding 0.2mL of 12.5mg / mL taurocholic acid solution to the air chamber. The embryo egg addition method and hatching procedure are the same as in Example 1.

[0056] After the broilers hatched, 96 chicks with similar weight and hatching time were selected from each treatment. Each treatment was randomly divided into 6 replicates, with 16 chickens in each replicate. The chicks were raised according to the standardized feeding procedure until 42 days, divided into the early stage of 1-21 days (0-3wk) and the late stage of 21-42 days (3-6wk). During the experiment, the broilers had free access to food and water, and the production performance was statistically analyzed every week. The composition of the experimental diet is shown in Table 1. On the day of hatching (D0), 21 days of age (D21), and 42 days of age (D42), broilers with similar weight to the average weight of the group were selected from each group, and the weight was calculated. Blood was collected from the wing vein, and plasma was separated by centrifugation at 3,000 rpm for 15 minutes at 4°C, and the plasma was divided into centrifuge tubes at -20°C for testing. The chickens were killed by neck dislocation, and the liver, breast muscle and leg muscle were separated and weighed. The organ index = organ weight / live weight × 100%. Biceps femoris tissue samples were collected, placed in 2 mL cryovials, quickly frozen in liquid nitrogen, and stored at -80°C for testing.

[0057] Table 1 Composition and nutritional level of experimental diets

[0058]

[0059]

[0060] 1 The premix provides per kg of feed: VA, 8000IU; VD3, 1000IU; VE, 20IU; VK, 0.5mg; VB1, 2mg; VB2, 8mg; VB3, 35mg; VB5, 10mg; VB6, 3.5mg; VB12, 0.01mg; biotin, 0.18mg; folic acid, 0.55mg; choline, 1300mg; iron, 100mg; zinc, 100mg; manganese, 120mg; copper, 8mg; iodine, 0.7mg; selenium, 0.3mg;

[0061] 2 The premix provides per kg of feed: VA, 6000IU; VD3, 750IU; VE, 10IU; VK, 0.5mg; VB1, 2mg; VB2, 5mg; VB3, 30mg; VB5, 10mg; VB6, 3mg; VB12, 0.01mg; biotin, 0.15mg; folic acid, 0.55mg; choline, 1000mg; iron, 80mg; zinc, 80mg; manganese, 100mg; copper, 8mg; iodine, 0.7mg; selenium, 0.3mg;

[0062] 3 Measured values ​​of nutrient composition.

[0063] 2. Determination indicators and methods

[0064] (1) Hatching performance: Count the hatching rate; count the weight of each chick on the day of hatching and calculate the average weight;

[0065] (2) Starting from 480 hours after incubation, the time when all chicks are out of the eggshell is recorded.

[0066] (3) Growth performance: body weight, daily weight gain, feed intake, feed-to-weight ratio, and mortality rate were recorded on a weekly basis during the feeding period;

[0067] (4) Organ index: On the day of hatching, 21 days of age (D21) and 42 days of age (D42), one broiler with a body weight close to the average was selected from each replicate, blood was collected from the wing vein and then bled out of the neck, and the liver, breast muscle and leg muscle were separated, weighed and the organ index was calculated. Organ index = organ weight / live weight × 100%.

[0068] (5) Determination of lipid content: According to the instructions of the kit (Nanjing Jiancheng Bioengineering Institute), the contents of triglycerides (TG) and free fatty acids (NEFA) in YSC and YSM were determined by spectrophotometry. The contents of glycerol, total cholesterol (TCH) and free cholesterol (FCH) in YSC and YSM were detected using a glycerol colorimetric assay kit (E-BC-K340-M, Elabscience), a total cholesterol colorimetric assay kit (E-BC-K109-M, Elabscience) and a free cholesterol colorimetric assay kit (E-BC-K004-M, Elabscience). Cholesterol ester (CE) = TCH-FCH.

[0069] (6) Blood biochemical indicators: Blood was collected from the wing vein, centrifuged at 3,000 rpm for 15 min at 4°C to separate plasma, and then dispensed into centrifuge tubes and stored at -20°C for testing. The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin (ALB), total protein (TP), TG, TCH, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were measured using an automatic biochemical analyzer. The kit was purchased from Wako Pure Chemical Industries, Ltd., Japan. NEFA was tested according to the kit instructions and purchased from Nanjing Jiancheng Bioengineering Institute.

[0070] (7) Detection of YSM gene mRNA level: Total RNA was extracted from YSM using TRIzol reagent (NCM Biotech). The RNA concentration and quality were measured using a NanoDrop spectrophotometer (DeNovix) and then reverse transcribed to obtain cDNA. Primers were designed using Primer5.0 software (SPS Inc., CA, USA) and synthesized by Sangon Biotechnology (Shanghai, China). The mRNA values ​​were normalized to the expression of chicken GAPDH mRNA and compared using 2 -ΔCT Methods Gene expression levels were determined.

[0071] (8) Statistics

[0072] The data were analyzed using the SAS (Version 8c, SAS Institute, 1998) statistical software ANOVA method. The single-factor ANOVA model was used to analyze the regulatory effect of adding taurocholic acid to embryonated eggs on broiler hatching performance, growth performance, lipid content, gene expression and blood biochemical indicators. Duncan's method was used for multiple comparisons. The experimental data were expressed as mean ± standard deviation (Mean ± SD), and P < 0.05 was considered significant.

[0073] 3. Test results

[0074] (1) Study on the appropriate time and dosage of adding TCA to embryonated eggs

[0075] Effects of adding different concentrations of taurocholic acid at different embryo ages on hatchability, yolk sac density and chick weight Figure 2 As shown, Figure 2 (A) is the hatching rate, Figure 2 Middle (B) is the specific gravity of E16 yolk sac, Figure 2 Middle (C) is the specific gravity of the yolk sac at D0, Figure 2 Middle (D) is the weight of E16 chicken embryo. Figure 2 (E) is the weight of chicks at D0; it can be seen that the hatching rate of different concentrations of TCA added at E9 is lower than that at E11. The hatching rate of adding 2.5 mg TCA at E9 is 25% lower than that of adding 2.5 mg TCA at E11. At E16, the yolk sac gravity of E11 after adding 2.5 mg TCA was significantly lower than that of the PC group, and the chicken embryo weight was significantly higher than that of the NC group (P<0.05). At D0, the yolk sac gravity of E11 after adding 2.5 mg TCA was significantly reduced, and the chick weight was significantly higher than that of the NC group (P<0.05). Based on the above results, adding 2.5 mg / piece TCA at E11 has the best effect on chicken embryo yolk sac absorption, weight gain and hatching rate.

[0076] (2) Effect of adding taurocholic acid to embryonated eggs on the hatching time of chicks

[0077] Effect of adding taurocholic acid to embryonated eggs on the hatching time of chicks Figure 3 As shown in the figure, it can be seen that after adding TCA to the eggs of Hy-Line brown laying hens, the peak of hatching is about 495 hours after incubation, while the peak of hatching of chicks in the NC group and PC group is about 500 hours after incubation. The hatching time of AA broiler chickens in the PC group and the TCA group has a similar incubation time trend, with the peak of hatching being about 500 hours after incubation, while the peak of hatching in the NC group is about 510 hours after incubation. In summary, the addition of TCA to embryonated eggs significantly advances the hatching time, shortens the incubation time, and improves the breeding efficiency.

[0078] (3) Effects of adding taurocholic acid to embryonated eggs on embryonic development of Hy-Line Brown laying hens during incubation

[0079] The effect of adding taurocholic acid to embryonated eggs on the embryonic growth performance of Hy-Line Brown laying hens during incubation is shown in Table 2. As shown in Table 2, adding TCA to embryonated eggs significantly increased the embryo weight at E16 (P<0.05). At E16, the yolk sac index of the TCA group was significantly reduced compared with the NC group (P<0.05). However, there was no significant difference in the liver, breast muscle and leg muscle index between the TCA group and the control group (P>0.05).

[0080] Table 2 Effects of adding TCA to embryonated eggs on body weight and organ indexes of E16 Hy-Line Brown laying hens

[0081]

[0082] Note: Data are expressed as Mean±SD (n=8). a,b Items marked with different letters indicate significant differences (P<0.05).

[0083] The effects of adding taurocholic acid to embryonated eggs on the hatchability and organ indexes of Hy-Line Brown laying hens after hatching are shown in Table 3. Figure 3 The middle (A) is a Hy-Line brown laying hen; Figure 3 Middle (B) is AA broiler; the hatchability of each treatment group was above 90%, indicating that the addition of TCA to the air chamber at embryonic age E11 would not have a negative impact on the hatchability and mortality of Hy-Line Brown laying hens. At D0, the weight of chicks in the TCA group was significantly higher than that in the PC group (P<0.05). Compared with the NC and PC groups, the yolk sac index in the TCA group was significantly lower (P<0.05), the liver index in the TCA group was significantly higher than that in the PC group (P<0.05), the leg muscle index in the TCA group was significantly higher than that in the NC and PC groups (P<0.05), and there was no significant difference in the breast muscle index among the treatment groups (P>0.05).

[0084] In summary, adding TCA to the air chamber at embryonic age E11 did not affect the hatchability and mortality of Hy-Line Brown laying hens, reduced the yolk sac index of broiler chickens at embryonic age E16 and after hatching, significantly increased the body weight of chicks at embryonic age E16 and after hatching, and significantly increased the leg muscle index after hatching.

[0085] Table 3 Effects of adding TCA to embryonated eggs on hatchability and weight and organ indexes of Hy-Line Brown laying hens at D0

[0086]

[0087] Note: Data are expressed as Mean±SD (n=8). a,b Items marked with different letters indicate significant differences (P<0.05).

[0088] (4) Effect of adding taurocholic acid to embryonated eggs on embryonic development of AA broiler chickens during incubation

[0089] The effect of adding taurocholic acid to embryonated eggs on the growth performance of AA broiler embryos during incubation is shown in Table 4. As shown in Table 4, the addition of TCA to embryonated eggs significantly increased the embryo weight at E16 (P<0.05). At E16, the yolk sac index of the TCA group was significantly reduced compared with the NC and PC groups (P<0.05). Compared with the PC group, the liver index of the TCA group was significantly increased (P<0.05), and the breast muscle index in the TCA group was significantly higher than that in the NC group (P<0.05), but there was no significant difference in the leg muscle index between the TCA group and the control group (P>0.05).

[0090] Table 4 Effects of adding TCA to embryonated eggs on body weight and organ indexes of E16 broilers

[0091]

[0092] Note: Data are expressed as Mean±SD (n=8). a,b Items marked with different letters indicate significant differences (P<0.05).

[0093] The effects of adding taurocholic acid to embryonated eggs on the hatchability and organ indexes of AA broilers after hatching are shown in Table 5. As shown in Table 5, the hatchability of each treatment group was above 90%, and the hatchability of the TCA group was higher than that of the NC group and the PC group, indicating that the addition of taurocholic acid to the air chamber at embryonic age 11 had no negative impact on the hatchability and mortality of broilers. At D0, the weight of chicks in the TCA group was significantly higher than that in the PC group (P<0.05). Compared with the NC and PC groups, the yolk sac index of the TCA group was significantly lower (P<0.05), and the leg muscle index in the TCA group was significantly higher than that in the PC group (P<0.05), while there was no significant difference in the liver index and breast muscle index among the treatment groups (P>0.05).

[0094] In summary, adding taurocholic acid to the air chamber at embryonic age E11 did not affect the hatchability and mortality of broiler chickens, reduced the yolk sac index of broiler chickens at embryonic age E16 and after hatching, significantly increased the body weight of chicks at embryonic age E16 and after hatching, and significantly increased the leg muscle index of chicks after hatching.

[0095] Table 5 Effects of adding TCA to embryonated eggs on hatchability and D0 broiler body weight and organ indexes

[0096]

[0097] Note: Data are expressed as Mean±SD (n=8). a,b Items marked with different letters indicate significant differences (P<0.05).

[0098] (5) Effect of adding taurocholic acid to embryonated eggs on lipid transport in the yolk sac of chicken embryos

[0099] Effect of adding taurocholic acid to embryonated eggs on lipid content in yolk sac of Hy-Line Brown laying hens Figure 4 .like Figure 4 As shown, Figure 4 (A) is triglyceride (TG), Figure 4 (B) is free fatty acid (NEFA), Figure 4 (C) is glycerol. Figure 4 The middle (D) is total cholesterol (TCH), Figure 4 The middle (E) is free cholesterol (FCH), Figure 4(F) is cholesterol ester (CE); in YSC, TG in TCA group was significantly lower than that in NC group (P<0.05), and compared with PC group, NEFA, glycerol, TCH and FCH contents in TCA group were significantly lower (P<0.05). In YSM, NEFA content in TCA group was significantly higher than that in PC group (P<0.05).

[0100] Effect of adding taurocholic acid to embryonated eggs on lipid content of yolk sac in AA broiler chickens Figure 5 .like Figure 5 As shown, Figure 5 (A) is triglyceride (TG), Figure 5 (B) is free fatty acid (NEFA), Figure 5 (C) is glycerol. Figure 5 (D) is total cholesterol (TCH), Figure 5 (E) is free cholesterol (FCH), Figure 5 (F) is cholesterol ester (CE); in YSC, TG in TCA group was significantly lower than that in NC and PC groups (P<0.05), and CE content in TCA group was significantly lower than that in NC group (P<0.05). In YSM, NEFA content in TCA group was significantly higher than that in PC group (P<0.05).

[0101] Effects of adding taurocholic acid to embryonated eggs on the mRNA levels of genes related to lipid transport in the yolk sac membrane of chicken embryos are shown in Figure 6 ,in Figure 6 The middle (A) is a Hy-Line brown laying hen. Figure 6 Middle (B) is AA broiler; the experimental results show that in Hy-Line Brown laying hens YSM, adding TCA to embryonated eggs can upregulate the expression of lipid transport-related genes such as FABP3, APOA1 and MTP. In AA broiler YSM, adding TCA to embryonated eggs can upregulate the expression of lipid transport-related genes such as FABP1, FABP3 and APOB.

[0102] The above results indicate that adding TCA to embryonated eggs can promote the transport of lipids from YSC to YSM by upregulating the expression of mRNA of genes related to lipid transport in YSM, thereby promoting embryonic growth and development, shortening the incubation time, and increasing the weight of chicks.

[0103] (6) Effect of adding taurocholic acid to embryonated eggs on the growth performance of broiler chickens

[0104] Effects of adding taurocholic acid to embryonated eggs on the growth performance of broiler chickens after hatching Figure 7 and Table 6. From Table 6 and Figure 7 ,in Figure 7 (A) is the average weight, Figure 7 Middle (B) is the average daily weight gain, Figure 7 (C) is the average daily feed intake. Figure 7 (D) is the feed-to-weight ratio; it can be seen that the hatching rate of each treatment group is about 88%. The addition of TCA to embryonated eggs significantly increased the weight of chicks after hatching (P<0.05). During the entire feeding period (1-42 days of age), the weight of TCA broilers was significantly higher than that of the PC group (P<0.05), and at 7 days, 14 days and 21 days of age, the weight of the TCA group was significantly higher than that of the PC group and the NC group (P<0.05). At 7 days and 14 days of age, the average daily weight gain of broilers in the TCA group was significantly higher than that of the NC group (P<0.05), and the average daily weight gain of broilers in the 1-21 day age stage was significantly higher in the TCA group than in the PC group and the NC group (P<0.05). Compared with the PC group, the average daily weight gain of the 21-42 day age stage and the entire 1-42 day age stage was significantly higher in the TCA group (P<0.05). Compared with the NC group, TCA treatment significantly reduced the feed-to-weight ratio in the 1-21 day age stage and the 1-42 day age stage (P<0.05), and the feed weight in the 21-42 day age stage showed a decreasing trend (P=0.066). There was no significant difference in feed intake and mortality rate between the groups in the 1-42 day age stage (P>0.05), and the mortality rate was lower in the TCA group.

[0105] In summary, adding taurocholic acid to embryonated eggs at the E11 embryonic age will not affect the hatching rate of broiler chickens, but will significantly increase the weight of chicks after hatching and the weight of broilers during the entire feeding period of 1-42 days of age, reduce the feed-to-weight ratio, significantly increase the average daily weight gain, and there is no significant change in the average daily feed intake and mortality rate.

[0106] Table 6 Effect of adding TCA to embryonated eggs on hatchability and growth performance of broiler chickens

[0107]

[0108]

[0109] Note: Data are expressed as Mean ± SEM (n = 6). a,b Items marked with different letters indicate significant differences (P<0.05).

[0110] (7) Effect of adding taurocholic acid to embryonated eggs on broiler organ index

[0111] Effects of adding taurocholic acid to embryonated eggs on organ indices of broiler chickens after hatching Figure 8 ,in Figure 8 (A) is the liver index, Figure 8 Middle (B) is the chest muscle index, Figure 8 (C) is the leg muscle index; Figure 8It can be seen that at D0, there were no significant differences in the liver, pectoral muscle and leg muscle indexes among the three groups (P>0.05). At E21 days of age, the pectoral muscle weight in the TCA group was significantly higher than that in the NC group (P<0.05), but there were no significant differences in the liver and leg muscle indexes between the TCA group, the PC group and the NC group (P>0.05). At E42 days of age, the liver index in the TCA group was significantly lower than that in the NC group (P<0.05), on the contrary, the leg muscle index in the TCA group was significantly higher than that in the NC group (P<0.05), and there was no significant difference in the pectoral muscle index among the groups (P>0.05).

[0112] (8) Effects of adding taurocholic acid to embryonated eggs on blood biochemical parameters of broiler chickens

[0113] The effects of adding taurocholic acid to embryonated eggs on the blood biochemical parameters of broiler chickens at E21 days of age are shown in Table 7. As shown in Table 7, at E21 days of age, compared with the NC group, the content of ALB in plasma in the TCA group was significantly reduced (P<0.05), compared with the NC and PC groups, the content of TG, TCH and HDL-C in plasma in the TCA group was significantly reduced (P<0.05), and compared with the PC group, the content of LDL-C and NEFA in the TCA group was significantly reduced (P<0.05). However, there were no significant differences in the content of ALT, AST and TP in plasma among the groups (P>0.05).

[0114] Table 7 Effects of adding TCA to embryonated eggs on plasma biochemical parameters of broiler chickens at E21

[0115]

[0116] Note: Data are expressed as Mean±SD (n=6). a,b Items marked with different letters indicate significant differences (P<0.05).

[0117] The effect of adding taurocholic acid to embryonated eggs on the blood biochemical indexes of broilers at E42 days of age is shown in Table 8. As shown in Table 8, at E42 days of age, compared with the NC group, the levels of TCH and HDL-C in plasma in the TCA group were significantly reduced (P<0.05), but there were no significant differences in the levels of ALT, AST, ALB, TP, TG, LDL-C and NEFA in plasma among the groups (P>0.05). In summary, the addition of taurocholic acid to embryonated eggs significantly reduced the blood lipid content of broilers.

[0118] Table 8 Effects of adding TCA to embryonated eggs on plasma biochemical parameters of broiler chickens E42

[0119]

[0120]

[0121] Note: Data are expressed as Mean±SD (n=6). a,b Items marked with different letters indicate significant differences (P<0.05).

[0122] (9) Effect of adding taurocholic acid to embryonated eggs on the mRNA levels of regulatory factors related to proliferation and differentiation of broiler leg muscles

[0123] Effects of adding taurocholic acid to embryonated eggs on the mRNA levels of regulatory factors related to proliferation and differentiation of broiler leg muscles Fig. 9 ,in Fig. 9 Where (A) is D0, Fig. 9 (B) is D21, where Fig. 9 (C) is D42. Fig. 9 As shown in the figure, at D0, the mRNA expression levels of leg muscle proliferation and differentiation-related regulatory factors MyoD, MyoG, Myf5, PAX3, PCNA and MRF4 were significantly increased in the TCA group compared with the PC group (P<0.05). At 21 days of age, the mRNA expression of MyoD, Myf5 and PAX3 in the leg muscle of the TCA group was significantly higher than that of the PC group (P<0.05). At D42 days of age, the mRNA expression of MyoG, Myf5 and PAX3 in the leg muscle of the TCA group was significantly higher than that of the NC and PC groups (P<0.05). In summary, the addition of TCA to embryonic eggs promotes muscle development and improves meat production by upregulating the mRNA levels of leg muscle proliferation and differentiation-related regulatory factors at D0, D21 and D42.

[0124] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for increasing the weight of chicks out of the shell and promoting early growth and development, characterized in that: Taurocholic acid solution was added into the air cells of chick embryos.

2. The method for increasing the hatching weight of chicks and promoting early growth and development according to claim 1, characterized in that: The taurocholic acid solution is a sterile physiological saline solution of taurocholic acid.

3. The method for increasing the hatching weight of chicks and promoting early growth and development according to claim 1, characterized in that: The concentration of the taurocholic acid solution is 5-25 mg / mL; preferably, the concentration of the taurocholic acid solution is 12.5 mg / mL.

4. The method for increasing the hatching weight of chicks and promoting early growth and development according to claim 1, characterized in that: The amount of the taurocholic acid solution added is 0.1-0.5 mL; preferably, the amount of the taurocholic acid solution added is 0.2 mL.

5. The method for increasing the hatching weight of chicks and promoting early growth and development according to claim 1, characterized in that: The chicken embryos are chicken embryos hatched to 9-11 embryonic ages; preferably, the chicken embryos are chicken embryos hatched to 11 embryonic ages.

6. The method for increasing the hatching weight of chicks and promoting early growth and development according to claim 1, characterized in that: The method further comprises filtering and sterilizing before adding the taurocholic acid solution; preferably, the filtering and sterilizing is performed by using a 0.22 μm sterile filter.

7. Use of taurocholic acid in increasing the hatching weight of chicks and promoting early growth and development.

8. The use of taurocholic acid in increasing the hatching weight of chicks and promoting early growth and development according to claim 7, characterized in that: The method of increasing the hatching weight of chicks and promoting early growth and development is to shorten the incubation time, improve the incubation performance, improve the growth performance, improve the organ index, improve the transport and absorption of nutrients in the yolk sac or reduce the blood lipid level.

9. A method for increasing the hatching weight of chicks and promoting early growth and development by using taurocholic acid, characterized in that: The method for increasing the hatching weight of chicks and promoting early growth and development as described in any one of claims 1 to 6 is adopted, and taurocholic acid is added into the air chamber of the chicken embryo.

10. Use of taurocholic acid in the preparation of a product for increasing the hatching weight of chicks and promoting early growth and development.

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