Method for raising chicken by using paeonia lactiflora and feed additive for improving egg quality

Abstract

The application discloses a method for improving egg quality by using peony and a feed additive, and belongs to the field of animal husbandry. The method for improving egg quality comprises adding 0.75-1.5% of peony stem and leaf powder in the basic daily ration of laying hens. The method can significantly improve the production performance of laying hens in the later production stage, and the effect is better than that of aureomycin. Meanwhile, the method can also significantly enhance the antioxidation ability of the body, improve the enrichment of MUFA, gamma-linolenic acid and arachidonic acid in eggs, and has the potential to replace feed antibiotics.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for improving egg quality, in particular, a method for improving egg quality by using peony to raise chickens and a feed additive. BACKGROUND

[0002] The research on chicken feed additives has always been an important topic in the field of agriculture and animal husbandry, aiming to improve the growth performance, health status and production efficiency of chickens. The following are some common chicken feed additives: (1) Antibiotic alternatives: As concerns about antibiotic overuse increase, researchers are looking for alternatives to maintain the health of poultry. Prebiotics, probiotics, plant extracts and other natural ingredients are being studied as antibiotic alternatives to promote gut health and immune system function. (2) Enzyme preparations: Enzyme preparations are added to feed to enhance the ability of chickens to absorb nutrients in feed. This helps to improve feed utilization, reduce feed costs, and improve the growth performance of chickens. (3) Antioxidants: Antioxidants can help reduce problems caused by stress and oxidative stress in chickens, such as illness and growth retardation. Vitamins, minerals and other natural antioxidants are being studied for use in feed. (4) Amino acid supplementation: Amino acids are the building blocks of proteins, and proper amino acid supply is essential for the growth and meat and egg production of chickens. Researchers adjust the content of amino acids in feed to meet the nutritional needs of chickens. (5) Fatty acid addition: Specific fatty acids, such as omega-3 fatty acids, are being studied to improve the health and production performance of chickens while improving the quality of meat and eggs. (6) Antiviral and immune enhancers: Some additives are being studied to enhance the immune system function of chickens and reduce the risk of disease. This may include vitamins, minerals and other natural immune enhancers.

[0003] However, there are currently the following problems with chicken feed additives: (1) Antibiotic overuse: For a long time, antibiotics have been widely added to feed to promote the growth of chickens and prevent disease. However, antibiotic overuse can lead to drug resistance problems, affecting human and animal health. Therefore, it is particularly important to find antibiotic alternatives and more sustainable methods. (2) Residual substances: Feed additives may leave residual substances in chicken meat and eggs, which may raise concerns about food safety and human health. It is crucial to ensure that the use of feed additives complies with food safety standards and is harmless to consumer health. (3) Environmental impact: The use of feed additives can increase waste and emissions in the rearing environment, affecting the surrounding environment. This may include problems such as pollution of water bodies, soil and air. Reducing environmental impact and adopting more environmentally friendly rearing practices are crucial for sustainable agriculture. (4) Animal welfare: Certain feed additives may affect the welfare of chickens, such as affecting the behavior, health and comfort of chickens. (5) Cost-effectiveness: The use of additives may increase the cost of rearing, thereby affecting the price of chicken meat and eggs. SUMMARY

[0004] Therefore, the present application provides a method for improving egg quality by using peony to raise chickens and a feed additive.

[0005] The technical solution of the present application is as follows:

[0006] The present application provides a method for improving egg quality by adding 0.75-1.5% of peony stem and leaf powder to the basic daily ration of laying hens.

[0007] Optionally, the peony stem and leaf powder is added to the basic daily ration of laying hens in a proportion of 1.5% by mass.

[0008] Optionally, the basic daily ration is composed of the following ingredients in the following proportions by weight: corn 62.0%, soybean meal 24.5%, stone powder 8.0%, calcium hydrogen phosphate 1.2%, sodium chloride 0.3%, premix 4.0%; wherein the premix contains 10000IU of vitamin A, 3000IU of vitamin D3, 25IU of vitamin E, 2.5mg of vitamin B1, 5mg of vitamin B2, 0.02mg of vitamin B12, 0.1mg of biotin, 1mg of folic acid, 12mg of pantothenic acid, 30mg of nicotinic acid, 3.5mg of pyridoxine, 10mg of copper, 60mg of iron, 80mg of manganese, 70mg of zinc, and 0.2mg of selenium per kilogram.

[0009] Optionally, before adding 0.75-1.5% of peony stem and leaf powder to the basic daily ration of laying hens, the method further comprises the following steps: drying the peony stem and leaf in a drying oven at 50-65°C until constant weight, completely crushing the peony stem and leaf using a crusher, and then passing the crushed peony stem and leaf through a 60-100 mesh sieve to obtain the peony stem and leaf powder.

[0010] Optionally, the improvement of egg quality is to improve one or more of the following indicators:

[0011] Egg production rate; feed to egg ratio; serum total antioxidant capacity of laying hens; serum total superoxide dismutase level of laying hens; serum glutathione peroxidase level of laying hens; malondialdehyde content in serum of laying hens; serum antioxidant capacity of laying hens; unsaturated fatty acid content in egg yolk; γ-linolenic acid content in egg yolk; eicosatrienoic acid content in egg yolk; arachidonic acid content in egg yolk.

[0012] The improvement of the above indicators is as follows (1) or (2) or (3):

[0013] (1) improving the egg production rate of laying hens in the later production period and reducing the feed to egg ratio;

[0014] (2) improve the total antioxidant capacity of serum, the total superoxide dismutase and glutathione peroxidase levels in serum of laying hens in the later production period, reduce the content of malondialdehyde in serum of laying hens, and improve the antioxidant capacity of serum of laying hens;

[0015] (3) improve the content of unsaturated fatty acids, gamma-linolenic acid, eicosatrienoic acid and arachidonic acid in the yolk of laying hens in the later production period.

[0016] Optionally, the peony is Paeonia lactiflora 'Fen Yu Nu'.

[0017] The application further provides a feed additive for laying hens, which contains 0.75%-1.5% of peony stem and leaf powder by mass percentage.

[0018] Optionally, the feed additive for laying hens contains 1.5% of peony stem and leaf powder by mass percentage.

[0019] Optionally, the peony stem and leaf powder is obtained by drying peony stems and leaves in a drying oven at 50-65 DEG C to constant weight, completely crushing the peony stems and leaves by using a crusher, and then sieving the peony stems and leaves through a 60-100 mesh sieve.

[0020] Optionally, the peony is Paeonia lactiflora 'Fen Yu Nu'.

[0021] Beneficial effects:

[0022] Adding 1.5% of peony stem and leaf powder to the basic daily ration of laying hens can significantly improve the T-AOC, T-SOD and GSH-Px levels in serum of laying hens in the later production period, significantly reduce the content of MDA in serum of laying hens, improve the antioxidant capacity of serum of laying hens, and effectively improve the oxidative damage of laying hens, which may be related to the fact that the peony stem and leaf contains a variety of compounds with strong antioxidant activity. Adding 0.75% of peony stem and leaf to the basic daily ration of laying hens can significantly improve the content of MUFA, gamma-linolenic acid, eicosatrienoic acid and arachidonic acid in the yolk of laying hens in the later production period; adding 1.5% of peony stem and leaf powder can improve the content of MUFA in the yolk of laying hens, and significantly improve the content of gamma-linolenic acid and arachidonic acid.

[0023] In summary, adding 1.5% of peony stem and leaf to the basic daily ration of laying hens can significantly improve the production performance of laying hens in the later production period, and the effect is better than that of aureomycin, and at the same time, it can significantly enhance the antioxidant capacity of the body, improve the enrichment of MUFA, gamma-linolenic acid and arachidonic acid in eggs, and has the potential to replace feed antibiotics. DETAILED DESCRIPTION

[0024] Method for improving egg quality of chicken by using paeonia lactiflora and feed additive

[0025] I. Materials and methods

[0026] 1. Test materials

[0027] The stems and leaves of 'Fen Yu Nu' paeonia lactiflora used in the test (Yuehua, Shichunhong. Comparison of main photosynthetic characteristics of paeonia lactiflora 'Fen Yu Nu' and wild species [J]. North Horticulture, 2010(6): 127-130.) were collected from Jining Jiaxiang County Xiangyang Nursery Planting Professional Cooperative, placed in a 65℃ drying oven to constant weight, completely pulverized using a pulverizer, and then passed through a 60-mesh sieve before being sealed and dried for storage.

[0028] The test animals were provided by Jining Jiaxiang County Xiangyang Nursery Planting Professional Cooperative, and 300 healthy, 85-week-old Hy-Line White laying hens with similar body weight and egg production performance were selected.

[0029] 2. Reagents and instruments

[0030] Reagents: Boron trifluoride methanol solution was purchased from Shanghai Anpu Experimental Technology Co., Ltd.; methyl undecanoate, anhydrous methanol of chromatographic purity, and n-hexane were purchased from Shanghai McLean Biochemical Technology Co., Ltd.; reagents of analytical purity, such as potassium hydroxide and sodium chloride, were purchased from Beijing Chemical Reagent Co., Ltd., a national pharmaceutical group; total antioxidant capacity (T-AOC) kit, glutathione peroxidase (GSH-Px) kit, total superoxide dismutase (T-SOD) kit, peroxidase (POD) kit, catalase (CAT) kit, and malondialdehyde (MDA) kit were purchased from Nanjing Jianshen Biological Engineering Institute.

[0031] Instruments: Electronic digital vernier caliper was purchased from Ningbo Deli Office Supplies Co., Ltd.; ultra-precision electronic analytical balance was purchased from METTLER TOLEDO, Switzerland; eggshell strength tester and chicken egg full-function tester were purchased from ORKA, USA; vacuum freeze dryer was purchased from Beijing Songyuan Huaxing Technology Development Co., Ltd.; Milli-Q ultrapure water instrument was purchased from Millipore, USA; multifunctional enzyme label instrument and high-speed refrigerated centrifuge were purchased from Thermo Fisher, USA; ultraviolet spectrophotometer was purchased from Shanghai Yuanzhi Instrument Co., Ltd.; digital constant-temperature water bath was purchased from Shanghai Zhicheng Analytical Instrument Manufacturing Co., Ltd.; gas chromatograph was purchased from Agilent Technologies, USA.

[0032] 3. Test method

[0033] 3.1 Test grouping and basal diet

[0034] In this test, a single factor random grouping design was used. 300 healthy, 85-week-old Hyline white laying hens with similar body weight and egg production performance were randomly divided into 5 groups, with 6 replicates in each group and 10 hens in each replicate. The negative control group was fed with the basal diet; the positive control group was fed with the basal diet supplemented with 50 mg / kg aureomycin; the test groups I, II and III were fed with the basal diet supplemented with 0.75%, 1.5% and 3% of 'Powder Yunu' Paeonia suffruticosa stem and leaf powder, respectively. The pre-test period was 7 days, and the formal test period was 56 days. The basal diet was a corn-soybean meal type diet, which was composed of the following ingredients in percentage by weight: corn 62.0%, soybean meal 24.5%, stone powder 8.0%, dicalcium phosphate 1.2%, sodium chloride 0.3%, premix 4.0%, wherein the premix contained per kilogram: vitamin A 10000 IU, vitamin D3 3000 IU, vitamin E 25 IU, vitamin B1 2.5 mg, vitamin B2 5 mg, vitamin B12 0.02 mg, biotin 0.1 mg, folic acid 1 mg, pantothenic acid 12 mg, nicotinic acid 30 mg, pyridoxine 3.5 mg, copper 10 mg, iron 60 mg, manganese 80 mg, zinc 70 mg, selenium 0.2 mg; the nutritional levels were as follows: crude protein ≥ 16.0%, crude fiber ≤ 6.0%, crude ash ≤ 15.0%, 3.0% ≤ calcium ≤ 4.4%, total phosphorus ≥ 0.4%, 0.3% ≤ sodium chloride ≤ 0.8%, moisture ≤ 14.0%, 0.32% ≤ methionine ≤ 0.9%.

[0035] 3.2 Feeding and management

[0036] The test was conducted in Jining Jiaxiang County Xiangyang Nursery Planting Professional Cooperative. All the laying hens in each group were scattered under the gold leaf compound leaf Acer plantation. The area was surrounded by double-layer iron wire, which was divided into 30 small areas, corresponding to 30 replicates of hens. The hens were fed twice a day at 8:00 and 16:00, and they could freely eat and drink water. Eggs were collected at 9:00 and 17:00. The health status of the flock was monitored daily, and the number of dead and culled hens and the reasons were recorded. The henhouse was disinfected regularly.

[0037] 3.3 Determination of production performance indicators

[0038] The daily records of each repeat egg weight, egg number, broken soft egg number and the number of chickens, once a week to cut the material weighing, statistics of feed consumption, calculate the average egg weight, egg production rate (including broken eggs), broken soft egg rate, dead rate, average daily intake and feed ratio (including broken eggs). The formula: average egg weight (g / egg) = the number of eggs produced during the statistical period / the number of eggs produced during the statistical period; egg production rate (%) = total number of eggs during the statistical period / (number of test chickens x number of days in the statistical period) x 100; broken soft egg rate (%) = the number of broken soft eggs during the statistical period / the total number of eggs during the statistical period x 100; dead rate (%) = the number of dead chickens during the statistical period / the total number of chickens x 100; average daily intake (g / day / only) = total intake during the statistical period / (number of test chickens x number of days in the statistical period); feed ratio = feed consumption (kg) during the statistical period / egg weight (kg) during the statistical period.

[0039] 3.4 Egg quality index determination

[0040] On the 14th, 28th, 42nd and 56th days of the formal test, egg samples were collected, 3 eggs were randomly selected from each repeat, labeled and measured in time. Vernier caliper was used to measure the longitudinal diameter and transverse diameter of the egg samples, and the egg shape index was calculated. Eggshell strength tester was used to measure the eggshell strength. Thickness of the tip, middle and blunt end of the eggshell after removing the shell membrane was measured by micrometer, and the eggshell thickness was calculated. Egg white height, Haugh unit and yolk color were measured by egg full function tester. First, the egg weight was measured by electronic analytical balance, then the eggshell weight, yolk weight and egg white weight were measured after separating the egg white and yolk by yolk separator, and the relative weight of eggshell, yolk and egg white was calculated. The formula: egg shape index = longitudinal diameter / transverse diameter; eggshell thickness (mm) = (tip thickness + middle thickness + blunt end thickness) / 3; relative weight of eggshell (%) = eggshell weight / egg weight x 100; relative weight of yolk (%) = yolk weight / egg weight x 100; relative weight of egg white (%) = egg white weight / egg weight x 100.

[0041] 3.5 Serum antioxidant performance index determination

[0042] On the day of the end of the formal test, 3 chickens were randomly selected from each repeat, 18 chickens per group, and 3mL of blood was collected from the subclavian vein after 12h of water deprivation and placed in a heparin sodium anticoagulant tube. The serum was separated by centrifugation at 2800r / min for 8min at 4℃, the supernatant was aspirated into a 2mL centrifuge tube, numbered and temporarily stored in an ice box, then transferred to a-80℃ freezer for storage, and ready for inspection. Serum total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), malondialdehyde (MDA) were measured using the corresponding kits from Nanjing Jiancheng Biological Engineering Institute according to the instructions, and the results were calculated after measurement on the enzyme marker. Serum glutathione peroxidase (GSH-Px), catalase (CAT), peroxidase (POD) were also measured using the corresponding kits from the company according to the instructions, and the results were calculated after measurement on the ultraviolet spectrophotometer.

[0043] 3.6 Determination of fatty acid content in egg yolk

[0044] 3.6.1 Collection and processing of egg samples

[0045] On the day of the end of the formal test, egg samples were collected, 1 egg was randomly selected from each replicate, 6 eggs per group, and labeled and stored in a 4°C refrigerator for testing. The egg white and egg yolk of the egg samples were separated using an egg yolk separator, the egg yolk was placed in a vacuum freeze dryer and freeze-dried for 72 h, then taken out and ground and sieved using a high-throughput tissue grinder, sealed and stored in a -80°C refrigerator for testing.

[0046] 3.6.2 Sample pretreatment

[0047] The egg yolk sample was taken out and thawed, 0.50 g of the sample was weighed into a 15 mL screw cap glass bottle, 1.2 mL of methyl undecanoate n-hexane internal standard was added, mixed well, then 2.0 mL of 0.5 mol / L potassium hydroxide methanol solution was added, shaken well, heated in a 90°C water bath for 12 min, and then cooled to room temperature. After cooling, 2.0 mL of 14% boron trifluoride methanol was added, mixed well, heated in a 90°C water bath for 12 min, and then cooled to room temperature. 4 mL of saturated sodium chloride solution was added, mixed gently, centrifuged at 2500 rpm for 3 min, the upper organic phase was aspirated and filtered through a 0.22 μm organic filter into a sample bottle, and tested on the instrument.

[0048] 3.6.3 Detection conditions

[0049] Chromatographic column: Agilent DB-23 chromatographic column (60 mm x 0.25 mm x 0.25 μm); injection mode: split (30:1), injection volume: 1 μL; detector: flame ionization detector (FID), 250°C; carrier gas: nitrogen; temperature program: 50°C (3 min), temperature increased to 175°C at 25°C / min and maintained for 3 min, temperature increased to 200°C at 3°C / min and maintained for 20 min, temperature increased to 210°C at 2°C / min, temperature increased to 230°C at 6°C / min and maintained for 2 min.

[0050] 3.7 Statistical analysis of data

[0051] The experimental data were statistically analyzed using Microsoft Excel 2016 software. One-way analysis of variance (ANOVA) and correlation analysis were performed using spss 25.0 software. Multiple comparisons were made using the least significant difference (LSD) and Duncan's method. The final results were expressed as "mean ± standard deviation". P<0.05 was considered statistically significant. Mass spectrometry results were analyzed using Agilent Masshunter Workstation Qualitative Analysis Software B.08.00 software.

[0052] II. Results and analysis

[0053] 1. Effect of Paeonia lactiflora leaves on the production performance of laying hens

[0054] As shown in Table 1, the laying rate of the positive control group and the test group II was significantly higher than that of the negative control group (P<0.05), increasing by 4.17% and 3.28%, respectively. The laying rate of the test group I increased by 2.21% compared to the negative control group, but the difference was not significant (P>0.05). There was no significant difference in laying rate among the positive control group, test group I, and test group II (P>0.05). The laying rate of the test group III was significantly lower than that of the negative control group and the positive control group (P<0.05), decreasing by 10.50% and 14.67%, respectively. The average daily feed intake of the test groups was lower than that of the negative control group and the positive control group. The feed-to-egg ratio of the test group I and the test group II was lower than that of the negative control group and the positive control group, but the difference was not significant (P>0.05). The feed-to-egg ratio of the test group III was significantly higher than that of the other four groups (P<0.05). The average egg weight of the positive control group and the test groups was lower than that of the negative control group, but there was no significant difference (P>0.05). The broken and soft egg rate of the test groups was lower than that of the negative control group and the positive control group, but the difference was not significant (P>0.05). The cull rate of the test group I and the test group II was lower than that of the negative control group and the positive control group, but there was no significant difference (P>0.05).

[0055] In summary, the addition of 1.5% Paeonia lactiflora leaves to the diet significantly increased the laying rate of laying hens and reduced the feed-to-egg ratio. The addition of 0.75% Paeonia lactiflora leaves had no significant effect on the laying rate, average daily feed intake, feed-to-egg ratio, average egg weight, broken and soft egg rate, and cull rate of laying hens. The addition of 3% Paeonia lactiflora leaves reduced the laying rate and average daily feed intake of laying hens and increased the feed-to-egg ratio.

[0056] Table 1 Effect of Paeonia lactiflora leaves on the production performance of laying hens

[0057]

[0058] Note: The same row data without letters or with the same letters means no significant difference (P>0.05), and different letters means significant difference (P<0.05).

[0059] 2. Effects of Paeonia stem and leaf on egg quality of laying hens

[0060] From Table 2, compared with the basic diet, the addition of aureomycin and Paeonia stem and leaf in the diet of laying hens had no significant effect on egg shape index, eggshell thickness, eggshell strength, egg white height, Haugh unit and yolk color (P>0.05). In terms of egg physical composition, there was no significant difference in eggshell relative weight among groups (P>0.05). Compared with the other four groups, the relative weight of egg yolk in test group III was significantly lower (P<0.05), while there was no significant difference among the other groups (P>0.05). The relative weight of egg white in test group III was significantly higher than that in the other groups (P<0.05), and the relative weight of egg white in test group I was lower than that in the other groups, while there was no significant difference among the negative control group, the positive control group and test group II (P>0.05).

[0061] Table 2 Effects of Paeonia stem and leaf on egg quality

[0062]

[0063] Note: The same row data without letters or with the same letters means no significant difference (P>0.05), and different letters means significant difference (P<0.05)

[0064] 3. Effects of Paeonia stem and leaf on serum antioxidant capacity of laying hens

[0065] From Table 3, the levels of T-AOC, GSH-Px and T-SOD in serum of Group II were significantly higher than those of other groups (P<0.05). Specifically, the levels of T-AOC, GSH-Px and T-SOD in Group II were 20.83%, 480.00%, 81.25%, 625.00% higher than those of the negative control group, the positive control group, Group I and Group III, respectively; the levels of GSH-Px were 11.16%, 41.21%, 15.07%, 42.73% higher, respectively; and the levels of T-SOD were 7.71%, 39.41%, 10.94%, 41.77% higher, respectively. The levels of T-AOC, GSH-Px and T-SOD in serum of the positive control group and Group III were significantly lower than those of the other three groups (P<0.05), but there was no significant difference between the positive control group and Group III (P>0.05). The levels of POD and CAT in serum of Group II were significantly higher than those of the positive control group and Group III (P<0.05), but there was no significant difference between Group II and the negative control group (P>0.05). Specifically, the level of POD in Group II was 16.78% and 21.58% higher than those of the positive control group and Group III, respectively; and the level of CAT was 87.68% and 50.57% higher, respectively. The content of MDA in serum of Group II was the lowest, which was significantly lower than that of other groups (P<0.05). Specifically, the content of MDA in Group II was 17.20%, 31.23%, 20.69% and 31.23% lower than those of the negative control group, the positive control group, Group I and Group III, respectively. The contents of MDA in serum of the positive control group and Group III were significantly higher than those of the other three groups (P<0.05), but there was no significant difference between the positive control group and Group III (P>0.05).

[0066] Table 3 Effects of Paeonia stem and leaf on antioxidant capacity of serum of laying hens

[0067]

[0068] Note: The same row data without letters or with the same letters means no significant difference (P>0.05), and the letters completely different means significant difference (P<0.05).

[0069] 4. Effects of Paeonia stem and leaf on fatty acid content in egg yolk of laying hens

[0070] 4.1 Effects of Paeonia stem and leaf on saturated fatty acid content in egg yolk of laying hens

[0071] From Table 4, the saturated fatty acids (SFA) content in each group of egg yolk from high to low was palmitic acid (C16:0), stearic acid (C18:0), myristic acid (C14:0), heptadecanoic acid (C17:0), heneicosylic acid (C21:0), pentadecanoic acid (C15:0) and arachidic acid (C20:0). Among them, the contents of palmitic acid, stearic acid and myristic acid in the positive control group, test group I and test group II were higher than those in the negative control group; the contents of palmitic acid and myristic acid in test group III were higher than those in the negative control group; the content of heptadecanoic acid in the positive control group and test group I was significantly lower than that in the negative control group (P<0.05), and there was no significant difference between test group II and test group III and the negative control group (P>0.05). The content of pentadecanoic acid in the negative control group was significantly higher than that in the positive control group and test group I (P<0.05), and there was no significant difference with test group II (P>0.05). The content of heneicosylic acid in the negative control group was significantly lower than that in the positive control group, test group II and test group III (P<0.05), and there was no significant difference with test group I (P>0.05). Overall, the total content of SFA in the positive control group, test group I and test group II was significantly higher than that in the negative control group (P<0.05), which increased by 7.49%, 11.02% and 9.89% respectively, and there was no significant difference between test group III and the negative control group (P>0.05).

[0072] Table 4 Effect of Paeonia stem and leaf on the content of saturated fatty acids (SFA) in egg yolk (mg / g)

[0073]

[0074] Note: The same row data without letters or with the same letters means no significant difference (P>0.05), and the letters are completely different, which means significant difference (P<0.05)

[0075] 4.2 Effect of Paeonia stem and leaf on the content of unsaturated fatty acids in egg yolk

[0076] As shown in Table 5, oleic acid (C18:1n9c) accounted for the highest proportion of monounsaturated fatty acids (MUFA) in egg yolk. The content of oleic acid, palmitoleic acid (C16:1) and myristoleic acid (C14:1) in the test group I was significantly higher than that in the other groups (P < 0.05), and the content of palmitoleic acid in the negative control group was significantly lower than that in the other groups (P < 0.05). The content of eicosapentaenoic acid (C20:1n9) in the test group II was the highest, which was significantly higher than that in the other groups (P < 0.05). The content of heptadecenoic acid (C17:1) in the positive control group and the test groups was significantly lower than that in the negative control group (P < 0.05). In addition, except for the test group III, the total content of MUFA in the other groups was higher than that in the negative control group. Specifically, the total content of MUFA in the test group I was the highest, which was significantly higher than that in the other groups (P < 0.05), and it was increased by 7.24% compared with the negative control group; the total content of MUFA in the positive control group and the test group II was increased by 3.20% and 0.83% respectively compared with the negative control group. The total content of MUFA in the test group III was significantly decreased by 4.78% compared with the negative control group (P < 0.05).

[0077] The polyunsaturated fatty acids (PUFA) with high content in egg yolk were linoleic acid (C18:2n6c), arachidonic acid (C20:4n6), α-linolenic acid (C18:3n3) and docosahexaenoic acid (C22:6n3, DHA). Among them, the content of α-linolenic acid and DHA in each group was significantly lower than that in the negative control group (P < 0.05). The content of α-linolenic acid in the positive control group, the test group I, the test group II and the test group III was decreased by 75.00%, 56.41%, 65.38% and 48.72% respectively, and the content of DHA was decreased by 45.86%, 21.02%, 25.48% and 33.76% respectively. Among other polyunsaturated fatty acids, the content of γ-linolenic acid (C18:3n6) and eicosatrienoic acid (C20:3n6) in the test groups was higher than that in the negative control group and the positive control group. The content of eicosapentaenoic acid (C20:5n3) in the negative control group was the highest, which was significantly higher than that in the other groups (P < 0.05), and the content of eicosapentaenoic acid in the positive control group was the lowest, which was significantly lower than that in the other groups (P < 0.05). The content of farnesidic acid (C20:2) in the positive control group, the test group II and the test group III was significantly higher than that in the negative control group and the test group I, and the content of farnesidic acid in the test groups increased with the increase of the proportion of Paeonia stem and leaf added.

[0078] Table 5 Effect of Paeonia stem and leaf on the content of unsaturated fatty acids (UFA) in egg yolk of laying hens (mg / g)

[0079]

[0080]

[0081] Note: The same row data without letters or with the same letters means no significant difference (P>0.05), and the letters are completely different, which means significant difference (P<0.05).

[0082] Overall, the ω-6 PUFA content of each group was not significantly different (P>0.05). The ω-3 PUFA content of each group was significantly lower than that of the negative control group (P<0.05), and the positive control group, test group I, test group II, and test group III decreased by 60.44%, 38.94%, 45.48%, and 41.43%, respectively. The ω-6 / ω-3 ratio of each group was significantly higher than that of the negative control group (P<0.05), and the positive control group, test group I, test group II, and test group III increased by 144.33%, 62.27%, 83.74%, and 67.94%, respectively. The PUFA content of each group was significantly lower than that of the negative control group (P<0.05), and the positive control group, test group I, test group II, and test group III decreased by 10.52%, 5.81%, 6.06%, and 6.59%, respectively. The PUFA content of the test groups was significantly higher than that of the positive control group (P<0.05), and test groups I, II, and III increased by 5.26%, 4.99%, and 4.39%, respectively.

[0083] The above results show that the addition of 1.5% of Paeonia stem and leaf to the diet can significantly improve the egg laying rate of laying hens in the later production period, reduce the feed egg ratio, and improve the production performance of laying hens, and its effect is better than that of aureomycin. This may be due to the active ingredients in Paeonia stem and leaf playing a role. The addition of 0.75% of Paeonia stem and leaf has no significant effect on the production performance of laying hens. The addition of 3% of Paeonia stem and leaf can significantly reduce the egg laying rate of laying hens, increase the feed egg ratio, and have a negative impact on the production performance of laying hens. This may be related to the excessive addition of Paeonia stem and leaf, and the anti-nutritional factors (such as tannin) contained in Paeonia stem and leaf are not conducive to the intake of nutrients by laying hens, thereby affecting the production of laying hens.

[0084] The addition of 0.75% and 1.5% of Paeonia stem and leaf to the diet has no significant effect on egg quality indicators such as egg shape index, eggshell thickness, eggshell strength, egg white height, Haugh unit, and egg yolk color, and does not significantly change the egg quality. The addition of 3% of Paeonia stem and leaf can significantly reduce the relative weight of egg yolk, to a certain extent, reducing the egg quality. This may be due to the excessive addition of Paeonia stem and leaf, and the anti-nutritional factors contained in Paeonia stem and leaf affect the in vivo utilization rate of minerals and trace elements, thereby reducing the relative weight of egg yolk.

[0085] Adding 1.5% of Paeonia stem and leaf in the diet can significantly improve the levels of T-AOC, T-SOD and GSH-Px in serum of laying hens in the later production period, significantly reduce the content of MDA in serum of laying hens, improve the antioxidant capacity of serum of laying hens, and effectively improve the oxidative damage of laying hens, which may be related to the fact that Paeonia stem and leaf contains a variety of compounds with strong antioxidant activity; adding 0.75% of Paeonia stem and leaf has no significant effect on the antioxidant capacity of serum of laying hens; and adding 3% of Paeonia stem and leaf can significantly reduce the levels of T-AOC, GSH-Px, T-SOD, CAT and POD in serum of laying hens, significantly increase the content of MDA, and have a negative impact on the antioxidant capacity of laying hens. It is speculated that the effect of Paeonia stem and leaf on the antioxidant capacity of serum of laying hens is related to the addition level, and the anti-nutritional factor tannin in Paeonia stem and leaf may play a certain role.

[0086] Adding 0.75% of Paeonia stem and leaf in the diet can significantly increase the contents of MUFA, γ-linolenic acid, eicosatrienoic acid and arachidonic acid in the yolk of laying hens in the later production period; adding 1.5% of Paeonia stem and leaf can increase the content of MUFA in the yolk of laying hens, and significantly increase the contents of γ-linolenic acid and arachidonic acid; adding 3% of Paeonia stem and leaf can significantly increase the content of γ-linolenic acid in the yolk of laying hens.

[0087] In summary, adding 1.5% of Paeonia stem and leaf in the diet can significantly improve the production performance of laying hens in the later production period, which is better than aureomycin, and can also significantly enhance the antioxidant capacity of the body, increase the enrichment of MUFA, γ-linolenic acid and arachidonic acid in eggs, and has the potential to replace feed antibiotics.

[0088] The above detailed description does not constitute a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the scope of the present application.

Claims

1. A method of improving the quality of chicken eggs, characterized by: The Paeonia lactiflora stem and leaf powder is added into the basic daily ration of the laying hens in a proportion of 0.75%-1.5% by mass percentage; the basic daily ration is composed of the following ingredients in percentage by mass: corn 62.0%, soybean meal 24.5%, stone powder 8.0%, calcium hydrogen phosphate 1.2%, sodium chloride 0.3%, premix 4.0%; wherein the premix contains, per kilogram, vitamin A 10000 IU, vitamin D3 3000 IU, vitamin E 25 IU, vitamin B1 2.5 mg, vitamin B2 5 mg, vitamin B12 0.02 mg, biotin 0.1 mg, folic acid 1 mg, pantothenic acid 12 mg, nicotinic acid 30 mg, pyridoxine 3.5 mg, copper 10 mg, iron 60 mg, manganese 80 mg, zinc 70 mg, selenium 0.2 mg; The improvement of the egg quality is to improve one or more of the following indexes: The content of γ-linolenic acid in the yolk; the content of eicosatrienoic acid in the yolk; the content of arachidonic acid in the yolk.

2. The method of improving the quality of chicken eggs according to claim 1, characterized in that: The Paeonia lactiflora stem and leaf powder is added into the basic daily ration of the laying hens in a proportion of 1.5% by mass percentage.

3. The method of improving the quality of chicken eggs according to claim 1, characterized in that: Before the Paeonia lactiflora stem and leaf powder is added into the basic daily ration of the laying hens in a proportion of 0.75%-1.5% by mass percentage, the method further comprises the following steps: drying the Paeonia lactiflora stem and leaf in a drying oven at 50-65°C until the weight is constant, completely crushing the Paeonia lactiflora stem and leaf by using a crusher, and then sieving the Paeonia lactiflora stem and leaf through a 60-100 mesh sieve to obtain the Paeonia lactiflora stem and leaf powder.

4. The method of improving the quality of chicken eggs according to any one of claims 1 to 3, characterized in that: The peony is 'Pink Princess' peony (Paeonia lactiflora 'Pink Princess') Paeonia lactiflora ‘Fen Yu Nu’ ).

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