A method for improving the egg-laying performance of Huaixiang chicken breeders under high temperature environment

Abstract

A method for improving the egg-laying performance of Huaixiang chicken breeders in a high temperature environment. By measuring the egg-laying rate of Huaixiang chicken breeders, the number of ovarian follicles of different grades, and the reproductive hormones of serum and ovaries, the action pathway of cantharicin on the ovaries of Huaixiang chicken breeders can be further analyzed, and the effect of cantharicin on the ovaries of Huaixiang chicken breeders can be further explained. For the first time, we focus on the regulatory effect of cantharicin on the ovarian tissue structure and function of Huaixiang chicken breeders in a high temperature environment, and explore the mechanism of the influence of cantharicin on the egg-laying rate and follicle development of female Huaixiang chicken breeders in a cyclic high temperature environment.

Description

Technical Field

[0001] The invention relates to the field of laying hen breeding, and in particular to a method for improving the egg-laying performance of Huaixiang chicken breeders under a high temperature environment. Background Art

[0002] The color of cantharidin is not affected by pH value, and it is also quite stable to sunlight and not easy to fade. Natural products exist in some mushrooms, crustaceans, fish, algae, eggs, blood, liver, etc.

[0003] In recent years, due to the increasing demand for free-range eggs, Cantharidin is often used as a feed additive for laying hens. The yolks of eggs laid by laying hens fed with Cantharidin have a darker color. Currently, people have mixed opinions about it; however, there have been no specific reports of harmful effects. Based on this, it is particularly necessary to conduct in-depth research on its mechanism of action in laying hens, so as to provide a scientific, reasonable and effective method to improve egg-laying performance in a high-temperature environment. Summary of the invention

[0004] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method for improving the egg-laying performance of Huaixiang chicken breeder hens in a high temperature environment, linking the egg-laying performance, the number of ovarian follicles of different grades, the reproductive hormones of serum and ovaries, etc., and deeply exploring the effects of Cantharidin on the egg-laying performance and ovarian physiological function of Huaixiang chicken breeder hens in a high temperature environment and its mechanism.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A method for improving the egg-laying performance of Huaixiang chicken breeders under a high temperature environment, specifically comprising adding cantharidin during feeding.

[0007] Furthermore, the dosage of Canthaxanthin is 8 mg / kg.

[0008] Furthermore, the specific steps are: divide the Huaixiang chicken breeders into a normal temperature group and a high temperature group, randomly divide into multiple groups and repeat, add cantharidin to the diet for 28-36 weeks, record the egg-laying performance, and then collect serum and ovarian homogenate to determine the effect of cantharidin on the egg-laying performance and ovarian physiological function of Huaixiang chicken breeders in a high temperature environment.

[0009] Furthermore, the egg-laying performance specifically includes: average daily feed intake, egg-laying rate, average egg weight, and soft egg rate.

[0010] Furthermore, the temperature of the high temperature group is 32±2°C; and the temperature of the normal temperature group is 25±2°C.

[0011] Furthermore, Cantharidin increased the average daily feed intake of Huaixiang chicken breeders, the egg production rate and average egg weight, and reduced the rate of broken soft eggs.

[0012] Furthermore, Cantharidin increased the number of follicles, SYF, LYF, SWF and LWF of Huaixiang chicken breeders.

[0013] Furthermore, Cantharidin increased the serum FSH level, serum LH level, serum E2 level, and serum P4 level of Huaixiang chicken breeders.

[0014] Furthermore, Cantharidin increased the ovarian FSH level and ovarian LH level of Huaixiang chicken breeders; and could increase the ovarian P4 level of Huaixiang chicken breeders.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] The present invention focuses for the first time on the regulatory effect of Cantharidin on the follicle development of Huaixiang chicken breeder hens in a high temperature environment, and explores the influence mechanism of Cantharidin on the egg-laying performance and ovarian physiological function of female Huaixiang chicken breeder hens in a high temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Flow chart of the method of the present invention. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0019] like Figure 1 As shown, a method for improving the egg-laying performance of Huaixiang chicken breeders in a high temperature environment.

[0020] Test example:

[0021] Research content

[0022] To explore the effects of adding Cantharidin to the diet on follicle development and egg-laying performance of Huaixiang breeder chickens in a high temperature environment.

[0023] Effect of Cantharidin on the number of graded follicles, SWF, SYF, LWF and LYF of Huaixiang chicken breeders in high temperature environment.

[0024] Effects of Cantharidin on egg-laying performance of Huaixiang breeder hens in high temperature environment.

[0025] During the experiment, eggs were collected at 6:00 p.m. every day, and the average daily feed intake (g / d. egg), egg production rate (%), average egg weight (g), and breakage rate (%) of each replicate were calculated weekly.

[0026] To explore the effect of adding Cantharidin to the diet on reproductive hormones of Huaixiang chicken breeders grown in a high temperature environment.

[0027] Effects of Cantharidin on serum reproductive hormones of Huaixiang breeder chickens in a high temperature environment.

[0028] Effect of Cantharidin on the levels of (follicle stimulating hormone FSH, luteinizing hormone LH, estradiol E2, progesterone P4) in the serum of Huaixiang chicken breeders under high temperature environment, ELISA (enzyme-linked immunosorbent assay).

[0029] Effects of Cantharidin on reproductive hormones in ovarian tissue of Huaixiang breeder chickens in high temperature environment.

[0030] Effect of Cantharidin on the contents of (follicle stimulating hormone FSH, luteinizing hormone LH, estradiol E2, progesterone P4) in ovarian tissue of Huaixiang chicken breeders under high temperature environment, ELISA (enzyme-linked immunosorbent assay).

[0031] At the 3rd, 6th and 9th weeks, one chicken was randomly selected from each replicate, killed by neck dislocation and the ovaries were quickly removed. The surface blood stains were treated with DEPC, quickly frozen in liquid nitrogen, and then stored in a -80℃ refrigerator for the preparation of tissue homogenate.

[0032] To explore the effect of adding Cantharidin to the diet on the number of follicles at various levels in the ovary of Huaixiang breeder chickens grown in a high temperature environment.

[0033] At the 3rd, 6th and 9th weeks, one chicken was randomly selected from each replicate, killed by neck dislocation, and the ovaries were quickly removed. Follicles with a diameter greater than 1 mm were quickly peeled off with ophthalmic forceps and weighed. The number of normal graded follicles, small yellow follicles and large white follicles was observed and recorded under the naked eye.

[0034] 1 Materials and methods

[0035] 1.1 Experimental animals

[0036] A total of 216 one-day-old female Huaixiang breeder chickens were purchased from Guangzhou Lilin Ecological Agriculture Co., Ltd. and raised to 26 weeks of age.

[0037] Cantharidin: purchased from DSM Vitamin Trading (Shanghai) Co., Ltd. of France, with a Cantharidin content of 10%.

[0038] 1.2 Feeding and management

[0039] The test site is in the chicken house of Guangdong Ocean University Animal Hospital. The chickens are kept in three-tiered cages, evenly distributed, and fed twice a day, at 8:00 a.m. and 18:00 p.m. The water trough and feed trough are cleaned once a week, and the chickens are disinfected once every half a month. A combination of natural light and artificial lighting is used. The light intensity during the test period is 10-15lux, and the light is controlled for 16h (16L:8D). The ambient temperature is strictly controlled by air conditioning, heat lamps, etc., so that the normal temperature group keeps the chicken house at (25±2℃), and the high temperature group uses a circulating high temperature of 32±2℃ for 8h (9:00-17:00). With the help of air conditioning, dehumidifiers, etc., the humidity of each group is ensured to be within the range of 65%-75%.

[0040] 1.3 Experimental design

[0041] 216 healthy Huaixiang breeder chickens of 26 weeks of age and similar weight were selected and randomly divided into 6 groups, with 6 replicates in each group and 6 chickens in each replicate. The temperature was maintained at 32±2℃ and the humidity in each group was maintained at 65-75%. The pre-test period was 2 weeks (26-27 weeks) and the full test period was 9 weeks (28-36 weeks). During the pre-test period, various environmental indicators were adjusted to meet the test requirements. The test groups are shown in Table 3.

[0042] Table 3 Experimental groups

[0043]

[0044]

[0045] 1.4 Experimental diet

[0046] Referring to the feeding standards for yellow-feathered broiler breeders in the "Professional Standards of the People's Republic of China", the diet was designed based on the breed and local conditions. A corn-soybean meal diet was used. The experimental basic diet formula is shown in Table 4.

[0047] Table 4 Composition and nutritional level of the experimental basal diet

[0048] Note: The nutritional level of the feed is a calculated value. The premix provides VA9000IU, VD 2500IU, VE20IU, VB1212μg, VK2.4 mg per kilogram of diet; trace elements Mn 100mg, Zn 60mg, Fe 25mg, Cu 5mg, Co 0.1mg (trace elements are added in the form of sulfate); and Se (N2SeO3·5H2O) 0.2mg, I (KI) 0.5mg.

[0049] 1.5 Main test reagents

[0050] Cantharidin: purchased from DSM Vitamin Trading (Shanghai) Co., Ltd. of France, with a Cantharidin content of 10%.

[0051] 1.6 Sample collection and determination

[0052] 1.6.1 Serum

[0053] One mouse was randomly selected from each replicate at 7:00, 8:00, and 9:00 on the day of the 3rd, 6th, and 9th week of the experiment. 5 mL of blood was collected using a heparin negative pressure tube. The mice were starved for 12 hours before blood collection and stored at -20°C. The blood was measured using a kit and an enzyme-labeled instrument.

[0054] 1.6.2 Ovarian tissue

[0055] On the 3rd, 6th and 9th week of the experiment, one chicken was randomly selected from each replicate, killed by neck dislocation and the ovaries were removed. The graded follicles were quickly peeled off, and the remaining part was weighed and then divided into two parts: one part was made into 10% tissue homogenate and stored at -20℃.

[0056] 2.2 Statistics

[0057] The experimental data were preliminarily sorted using WPS2019, and then spss23.0 was used for one-way analysis of variance, and the LSD method was used for multiple comparisons.

[0058] 2.2.1 Effect of Cantharidin on egg-laying performance of Huaixiang breeder hens in a cyclic high temperature environment

[0059] Table 5 Effects of Cantharidin on egg-laying performance of Huaixiang breeder chickens in a cyclic high temperature environment

[0060]

[0061] Note: Different lowercase letters in the same row indicate significant differences (P<0.05), and no letters or the same letters indicate no significant differences (P>0.05).

[0062] (1) Effect of Cantharidin on the average daily feed intake of Huaixiang breeder chickens in a cyclic high temperature environment

[0063] As shown in Table 5, in the early stage of the experiment, compared with the NC group, the average daily feed intake of the breeder chickens in the HC group was significantly reduced by 15.63% (P<0.05); compared with the HC group, the average daily feed intake of each HT group increased, but the difference was not significant (P>0.05). In the middle stage of the experiment, compared with the NC group, the average daily feed intake of the breeder chickens in the HC group was significantly reduced by 14.50% (P<0.05); compared with the HC group, the average daily feed intake of each HT group increased, but the difference was not significant (P>0.05).

[0064] In the later stage of the experiment, compared with the NC group, the average daily feed intake of the breeder chickens in the HC group was significantly reduced by 14.11% (P<0.01); compared with the HC group, the average daily feed intake of each HT group increased, among which the average daily feed intake of the breeder chickens in the HT4 group increased the most, significantly increasing by 14.14% (P<0.05), indicating that the addition of 10 mg / kg of canthaxanthin in the later stage can increase the feed intake of breeder chickens in a circulating high temperature environment. Compared with the NC group, the average daily feed intake of the breeder chickens in the HT4 group decreased by 1.96% (P>0.05), indicating that the addition of canthaxanthin can alleviate the adverse effects of circulating high temperature on the feed intake of breeder chickens, and the difference was not significant at the level close to normal temperature.

[0065] (2) Effect of Cantharidin on the egg production rate of Huaixiang breeder chickens in a cyclic high temperature environment

[0066] As shown in Table 5, in the early stage of the experiment, compared with the NC group, the egg production rate of the HC group was significantly reduced by 23.85% (P<0.01); compared with the HC group, the egg production rate of the breeders in each HT group increased, among which the egg production rate of the HT3 group increased the most, significantly increasing by 23.90% (P<0.01), indicating that the addition of 8 mg / kg of cantharidin in the early stage can improve the egg production rate of breeders in a circulating high temperature environment. Compared with the NC group, the egg production rate of the breeders in the HT3 group was significantly reduced by 5.65% (P<0.01), indicating that the addition of cantharidin in the early stage cannot completely eliminate the adverse effects of high temperature on egg production.

[0067] In the middle of the experiment, compared with the NC group, the egg production rate of the HC group was significantly reduced by 19.86% (P<0.01); compared with the HC group, the egg production rate of the breeders in each HT group increased, among which the egg production rate of the HT4 group increased the most, significantly increasing by 13.06% (P<0.05), indicating that the addition of 10 mg / kg of cantharidin in the middle period will increase the egg production rate of breeders in a circulating high temperature environment. Compared with the NC group, the egg production rate of the breeders in the HT4 group decreased by 9.40% (P>0.05), indicating that cantharidin can alleviate the adverse effects of high temperature on egg production, and the difference was not significant at the level close to normal temperature.

[0068] In the later stage of the experiment, compared with the NC group, the egg production rate of the HC group was significantly reduced by 22.80% (P<0.01); compared with the HC group, the egg production rate of each HT group was improved, among which the egg production rate of the HT4 group was the largest, significantly increased by 14.77% (P<0.05), indicating that adding 10 mg / kg of cantharidin in the later stage can improve the egg production rate of breeders in a circulating high temperature environment. Compared with the NC group, the egg production rate of the HT4 group was significantly reduced by 11.40% (P<0.01), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on egg production.

[0069] (3) Effect of Cantharidin on the average egg weight of Huaixiang breeder chickens in a cyclic high temperature environment

[0070] As shown in Table 5, in the early stage of the experiment, compared with the NC group, the average egg weight of the HC group was significantly reduced by 9.41% (P<0.01); compared with the HC group, the average egg weight of each HT group increased, among which the average egg weight of the HT3 group was the largest, significantly increased by 6.61% (P<0.05), indicating that the addition of 8 mg / kg of cantharidin in the early stage can increase the average egg weight of the breeders in the circulating high temperature environment. Compared with the NC group, the average egg weight of the HT3 group of breeders decreased significantly by 3.42% (P<0.01), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on the average egg weight.

[0071] In the middle of the experiment, compared with the NC group, the average egg weight of the HC group was significantly reduced by 13.09% (P<0.01); compared with the HC group, the average egg weight of each HT group increased, among which the average egg weight of the HT3 group was the largest, significantly increased by 9.46% (P<0.05), indicating that adding 8mg / kg of cantharidin in the middle period can increase the average egg weight of the breeders in the circulating high temperature environment. Compared with the NC group, the average egg weight of the HT3 group of breeders decreased significantly by 4.87% (P<0.01), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on the average egg weight.

[0072] In the later stage of the experiment, compared with the NC group, the average egg weight of the HC group was significantly reduced by 7.05% (P<0.01); compared with the HC group, the average egg weight of each HT group increased, among which the average egg weight of the HT3 group was the largest, significantly increased by 4.47% (P<0.05), indicating that adding 8mg / kg of cantharidin in the later stage can increase the average egg weight of the breeders in the circulating high temperature environment. Compared with the NC group, the average egg weight of the HT3 group of breeders decreased by 2.89% (P>0.05), indicating that cantharidin can eliminate the adverse effects of high temperature on the average egg weight, and the difference is not significant when it is close to the normal temperature level.

[0073] (4) Effect of Cantharidin on the breakage rate of Huaixiang chicken eggs in a circulating high temperature environment

[0074] As shown in Table 5, in the early stage of the experiment, compared with the NC group, the egg breakage rate of the HC group was significantly increased by 374.42% (P<0.01); compared with the HC group, the egg breakage rate of each HT group decreased, but the difference was not significant (P>0.05). In the middle stage of the experiment, compared with the NC group, the egg breakage rate of the HC group was significantly increased by 431.11% (P<0.01); compared with the HC group, the egg breakage rate of each HT group decreased, among which the egg breakage rate of the HT3 group decreased the most, significantly decreasing by 17.15% (P<0.05), indicating that the addition of 8 mg / kg of cantharidin in the middle stage can reduce the egg breakage rate of breeder hens in a circulating high temperature environment. Compared with the NC group, the egg breakage rate in the HT3 group was significantly increased by 340.00% (P<0.01), indicating that cantharidin cannot completely alleviate the adverse effects of high temperature on the egg breakage rate.

[0075] In the later stage of the experiment, compared with the NC group, the egg breakage rate of the HC group was significantly increased by 435.84% (P<0.01); compared with the HC group, the egg breakage rate of each HT group decreased, among which the egg breakage rate of the HT3 group decreased the most, significantly decreasing by 19.01% (P<0.05), indicating that the addition of 8 mg / kg of cantharidin in the later stage can reduce the egg breakage rate of breeder hens in a circulating high temperature environment. Compared with the NC group, the egg breakage rate in the HT3 group was significantly increased by 333.96% (P<0.01), indicating that cantharidin cannot completely alleviate the adverse effects of high temperature on the egg breakage rate.

[0076] 2.2.2 Effects of Cantharidin on follicular development of Huaixiang breeder chickens in a cyclic high temperature environment

[0077] Table 6 Effects of Cantharidin on follicle development of Huaixiang breeder chickens in a cyclic high temperature environment

[0078]

[0079]

[0080] (1) Effect of Cantharidin on the ovarian weight of Huaixiang breeder chickens in a cyclic high temperature environment

[0081] As shown in Table 6, in the early stage of the experiment, the ovarian weight of the HC group breeder chickens was significantly reduced by 32.62% (P<0.05) compared with the NC group. Compared with the HC group, the ovarian weight of the breeder chickens in each HT group increased, among which the HT4 group increased significantly by 33.33% (P>0.05). Compared with the NC group, the ovarian weight of the HT4 group decreased by 10.15% (P<0.05), close to the normal temperature level, and the difference was not significant. In the middle and late stages of the experiment, compared with the NC, the ovarian weight of the breeder chickens in the HC group decreased, but the difference was not significant (P>0.05).

[0082] (2) Effect of Cantharidin on the number of follicles in Huaixiang breeder chickens in a cyclic high temperature environment

[0083] As shown in Table 6, in the early stage of the experiment, compared with the NC group, the number of grade follicles in the HC group was significantly reduced by 39.49% (P<0.01); compared with the HC group, the number of grade follicles in each HT group increased, among which the increase in the number of grade follicles in the HT3 group was the largest, significantly increasing by 34.98% (P<0.05), indicating that the addition of 8 mg / kg of Cantharidin in the early stage can increase the number of grade follicles in the breeder chickens in the circulating high temperature environment. Compared with the NC group, the number of grade follicles in the HT3 group decreased by 18.32% (P<0.05), indicating that Cantharidin can partially alleviate the adverse effects of high temperature on the number of grade follicles.

[0084] In the middle and late stages of the experiment, the number of graded follicles in the HC group was lower than that in the NC group (P>0.05). There was no significant difference in the number of graded follicles in the breeder chickens in each HT group compared with the HC group (P>0.05).

[0085] (3) Effect of Cantharidin on the SWF number of Huaixiang breeder chickens in a cyclic high temperature environment

[0086] As shown in Table 6, in the early stage of the experiment, compared with the NC group, the SWF number of the HC group breeder chickens was significantly reduced by 34.46% (P<0.01); compared with the HC group, the SWF number of the HT4 group breeder chickens was significantly reduced by 25.56% (P<0.05), indicating that the addition of 10 mg / kg of cantharidin in the early stage reduced the SWF number of breeder chickens in the circulating high temperature environment. Compared with the NC group, the SWF number of the HT4 group breeder chickens was significantly reduced by 51.27% (P<0.01), indicating that cantharidin cannot eliminate the adverse effects of high temperature on the SWF number.

[0087] In the middle of the experiment, compared with the NC group, the SWF number of breeder chickens in the HC group was significantly reduced by 47.25% (P<0.01); compared with the HC group, the SWF number of breeder chickens in each HT group increased, among which the SWF number of breeder chickens in the HT2 group increased the most, significantly increasing by 65.62% (P<0.05). This shows that the addition of 6 mg / kg of cantharidin in the middle period increased the SWF number of breeder chickens in the circulating high temperature environment. Compared with the NC group, the SWF number of breeder chickens in the HT2 group decreased by 12.63% (P>0.05), indicating that cantharidin can partially alleviate the adverse effects of high temperature on the SWF number.

[0088] In the later stage of the experiment, compared with the NC group, the SWF number of breeder chickens in the HC group was significantly reduced by 10.27% (P<0.01); compared with the HC group, the SWF number of breeder chickens in each HT group was not significantly different (P>0.05).

[0089] (4) Effect of Cantharidin on SYF number of Huaixiang breeder chickens in a cyclic high temperature environment

[0090] As shown in Table 6, in the early stage of the experiment, compared with the NC group, the SYF number of the HC group breeder chickens was significantly reduced by 71.03% (P<0.01); compared with the HC group, the SYF number of the breeder chickens in each HT group increased, among which the SYF number of the breeder chickens in the HT4 group increased the most, significantly increasing by 172.47% (P>0.05), indicating that the addition of 10 mg / kg of cantharidin in the early stage increased the SYF number of the breeder chickens in the circulating high temperature environment. Compared with the NC group, the SYF number of the breeder chickens in the HT4 group decreased by 22.05% (P>0.05), indicating that the addition of 10 mg / kg of cantharidin in the early stage can partially alleviate the adverse effects of high temperature on the SYF number of the breeder chickens. In the middle and late stages of the experiment, compared with the NC group, there was no significant difference in the SYF number of the Huaixiang chicken breeder chickens in each group (P>0.05).

[0091] In summary, cyclic high temperature will reduce the SYF number of breeder chickens. In the early stage of the experiment, with the increase of cantharidin dosage, the SYF number of breeder chickens showed an upward trend, and the optimal dosage was 10 mg / kg.

[0092] (5) Effect of Cantharidin on LWF number of Huaixiang breeder chickens in a cyclic high temperature environment

[0093] As shown in Table 6, before and after the experiment, there was no significant difference in the number of LWF of breeder chickens in each HT group compared with the NC group (P>0.05). In the middle of the experiment, compared with the NC group, the number of LWF of breeder chickens in the HC group was significantly reduced by 20.81% (P<0.01); compared with the HC group, there was no significant difference in the number of LWF of breeder chickens in each HT group (P>0.05).

[0094] (6) Effect of Cantharidin on LYF number of Huaixiang chicken breeders in a cyclic high temperature environment

[0095] As shown in Table 6, in the early and middle stages of the experiment, the number of LYF of the breeder chickens in the HC group was significantly reduced by 57.08% (P<0.01) and 38.71 (P<0.01) respectively compared with the NC group; during the entire experiment, there was no significant difference in the number of LYF of the breeder chickens in each HT group compared with the HC group (P>0.05).

[0096] 2.2.4 Effects of Cantharidin on Serum Reproductive Hormone Levels in Huaixiang Breeders in Cyclic High Temperature Environment

[0097] Table 7 Effects of Cantharidin on serum reproductive hormone levels of Huaixiang chicken breeders in a cyclic high temperature environment

[0098]

[0099] (1) Effect of Cantharidin on serum FSH levels of Huaixiang breeder chickens in a cyclic high temperature environment

[0100] As shown in Table 7, in the early stage of the experiment, compared with the NC group, the serum FSH level of the breeder chickens in the HC group was significantly reduced by 35.28% (P<0.01); compared with the HC group, the serum FSH level of the breeder chickens in each HT group increased, among which the serum FSH level of the breeder chickens in the HT3 group increased the most, significantly increasing by 27.55% (P<0.01), indicating that the addition of 8 mg / kg of cantharidin in the early stage can improve the serum FSH level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the serum FSH level of the breeder chickens in the HT3 group was significantly reduced by 17.45% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on serum FSH levels.

[0101] In the middle of the experiment, compared with the NC group, the serum FSH level of the breeder chickens in the HC group was significantly reduced by 31.20% (P<0.01); compared with the HC group, the serum FSH level of the breeder chickens in each HT group increased, among which the serum FSH level of the breeder chickens in the HT3 group increased the most, significantly increasing by 19.59% (P<0.05), indicating that the addition of 8mg / kg of cantharidin in the middle period can improve the serum FSH level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the serum FSH level of the breeder chickens in the HT3 group decreased significantly by 17.72% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on serum FSH levels.

[0102] In the later stage of the experiment, compared with the NC group, the serum FSH level of the breeder chickens in the HC group was significantly reduced by 30.02% (P<0.01); compared with the HC group, the serum FSH level of the breeder chickens in each HT group increased, among which the serum FSH level of the breeder chickens in the HT3 group increased the most, significantly increasing by 20.29% (P<0.05), indicating that the addition of 8 mg / kg of cantharidin in the later stage can improve the serum FSH level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the serum FSH level of the breeder chickens in the HT3 group decreased significantly by 15.82% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on serum FSH levels.

[0103] (2) Effect of Cantharidin on serum LH levels in Huaixiang breeder chickens in a cyclic high temperature environment

[0104] As shown in Table 7, in the early stage of the experiment, compared with the NC group, the serum LH level of the breeder chickens in the HC group was significantly reduced by 21.04% (P<0.01); compared with the HC group, the serum LH levels of each group increased, but the difference was not significant (P<0.05).

[0105] In the middle of the experiment, compared with the NC group, the serum LH level of the breeder chickens in the HC group was significantly reduced by 24.03% (P<0.01); compared with the HC group, the serum LH level of the breeder chickens in each HT group increased, among which the serum LH level of the breeder chickens in the HT3 group increased the most, significantly increasing by 15.17% (P<0.05), indicating that the addition of 8 mg / kg of cantharidin in the middle period can increase the serum LH level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the serum LH level of the breeder chickens in the HT3 group was significantly reduced by 12.51% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on serum LH levels.

[0106] In the later stage of the experiment, compared with the NC group, the serum LH level of the breeder chickens in the HC group was significantly reduced by 27.25% (P<0.01); compared with the HC group, the serum LH level of the breeder chickens in each HT group was increased, among which the serum LH level of the breeder chickens in the HT3 group increased the most, significantly increasing by 18.12% (P<0.05), indicating that the addition of 8 mg / kg of cantharidin in the later stage can improve the serum LH level of breeder chickens in a circulating high temperature environment; compared with the NC group, the serum LH level of the breeder chickens in the HT3 group was significantly reduced by 14.07% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on serum LH levels.

[0107] (3) Effects of Cantharidin on serum E2 levels in Huaixiang breeder chickens in a cyclic high temperature environment

[0108] As shown in Table 7, in the early stage of the experiment, compared with the NC group, the serum E2 level of the HC group breeder chickens was significantly reduced by 35.06% (P<0.01); compared with the HC group, the serum E2 level of the breeder chickens in each HT group increased, among which the serum E2 level of the breeder chickens in the HT4 group increased the most, significantly increasing by 33.75% (P<0.01), indicating that the addition of 10 mg / kg of cantharidin in the early stage can improve the serum E2 level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the serum E2 level of the HT4 group decreased significantly by 13.14% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on serum E2 levels.

[0109] In the middle of the experiment, compared with the NC group, the serum E2 level of the HC group was significantly reduced by 31.13% (P<0.01); compared with the HC group, the serum E2 levels of the breeder chickens in each HT group were increased, but the differences were not significant (P<0.05).

[0110] In the later stage of the experiment, compared with the NC group, the serum E2 level of the breeder chickens in the HC group was significantly reduced by 20.31% (P<0.01); compared with the HC group, the serum E2 level of the breeder chickens in each HT group increased, among which the serum E2 level of the breeder chickens in the HT3 group increased the most, significantly increasing by 17.95% (P<0.01), indicating that the addition of 8 mg / kg of cantharidin in the later stage can improve the serum E2 level of the breeder chickens in the circulating high temperature environment. Compared with the NC group, the serum E2 level of the breeder chickens in the HT3 group decreased by 6.00% (P>0.05), indicating that cantharidin can alleviate the adverse effects of high temperature on the serum E2 level, and the difference was not significant when it was close to the normal temperature level.

[0111] (4) Effect of Cantharidin on Serum P4 Levels in Huaixiang Breeder Chickens in Cyclic High Temperature Environment

[0112] As shown in Table 7, in the early stage of the experiment, there was no significant difference in the serum P4 level of each group of breeder chickens compared with the NC group (P>0.05). In the middle stage of the experiment, compared with the NC group, the serum P4 level of the breeder chickens in the HC group was significantly reduced by 18.99% (P<0.05); compared with the HC group, the serum P4 level of the breeder chickens in each HT group increased, among which the serum P4 level of the breeder chickens in the HT4 group increased the most, significantly increasing by 23.44% (P<0.05), indicating that the addition of 10 mg / kg of cantharidin in the middle stage can increase the serum P4 level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the serum P4 level of the breeder chickens in the HT4 group was not significantly different (P>0.05), and returned to the normal temperature level. This shows that cantharidin can eliminate the adverse effects of high temperature on serum P4 levels, close to the normal temperature level, and the difference is not significant.

[0113] In the later stage of the experiment, compared with the NC group, the serum P4 level of the breeder chickens in the HC group was significantly reduced by 23.21% (P<0.05); compared with the HC group, the serum P4 levels of the breeder chickens in the HT group were increased, among which the serum P4 level of the breeder chickens in the HT3 group increased the most, significantly increasing by 24.86% (P<0.05). This shows that the addition of 8 mg / kg of cantharidin in the later stage can improve the serum P4 level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the serum P4 level of the breeder chickens in the HT3 group decreased by 4.12% (P>0.05), indicating that cantharidin can alleviate the adverse effects of high temperature on serum P4 levels, and the difference was not significant when approaching the normal temperature level.

[0114] 2.2.5 Effects of Cantharidin on ovarian reproductive hormone levels in Huaixiang breeder chickens in a cyclic high temperature environment

[0115] Table 8 Effects of Cantharidin on ovarian reproductive hormone levels of Huaixiang chicken breeders in a cyclic high temperature environment

[0116]

[0117] (1) Effect of Cantharidin on FSH levels in the ovaries of Huaixiang breeder chickens in a cyclic high temperature environment

[0118] As shown in Table 8, in the early stage of the experiment, compared with the NC group, the ovarian FSH level of the HC group was significantly reduced by 46.53% (P<0.01); compared with the HC group, the ovarian FSH levels of each HT group were increased, among which the ovarian FSH level of the HT3 group increased the most, significantly increasing by 52.51% (P<0.01), indicating that the early addition of 8 mg / kg of cantharidin can improve the ovarian FSH level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the ovarian FSH level of the HT3 group was significantly reduced by 18.46% (P<0.05), indicating that cantharidin cannot completely alleviate the adverse effects of high temperature on ovarian FSH levels.

[0119] In the middle of the experiment, compared with the NC group, the ovarian FSH level of the HC group was significantly reduced by 53.03% (P<0.01); compared with the HC group, the ovarian FSH level of each HT group increased, among which the ovarian FSH level of the HT3 group increased the most, significantly increasing by 56.08% (P<0.01), indicating that the addition of 8 mg / kg of cantharidin in the middle period can improve the ovarian FSH level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the ovarian FSH level of the HT3 group was significantly reduced by 26.70% (P<0.05), indicating that cantharidin cannot completely alleviate the adverse effects of high temperature on ovarian FSH levels.

[0120] In the later stage of the experiment, compared with the NC group, the ovarian FSH level of the HC group was significantly reduced by 50.21% (P<0.01); compared with the HC group, the ovarian FSH level of each HT group increased, among which the ovarian FSH level of the HT3 group increased the most, significantly increasing by 75.30% (P<0.01), indicating that the addition of 8 mg / kg of cantharidin in the later stage can improve the ovarian FSH level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the ovarian FSH level of the HT3 group was significantly reduced by 12.73% (P<0.05), indicating that cantharidin cannot completely alleviate the adverse effects of high temperature on ovarian FSH levels.

[0121] (2) Effect of Cantharidin on LH levels in the ovaries of Huaixiang breeder chickens in a cyclic high temperature environment

[0122] As shown in Table 8, in the early stage of the experiment, compared with the NC group, the ovarian LH level of the HC group was significantly reduced by 38.96% (P<0.01); compared with the HC group, the ovarian LH level of each HT group increased, among which the ovarian LH level of the HT3 group increased the most, significantly increasing by 43.23% (P<0.01), indicating that 8 mg / kg of cantharidin can improve the ovarian LH level of breeder chickens in a circulating high temperature environment in the early stage. Compared with the NC group, the ovarian LH level of the HT3 group was significantly reduced by 12.57% (P<0.05), indicating that cantharidin partially alleviated the adverse effects of high temperature on ovarian LH level.

[0123] In the middle of the experiment, compared with the NC group, the ovarian LH level of the HC group was significantly reduced by 36.18% (P<0.01); compared with the HC group, the ovarian LH level of each HT group increased, among which the HT3 group had the largest increase, significantly increasing by 24.57% (P<0.01), indicating that 8 mg / kg of cantharidin can improve the ovarian LH level of breeder chickens in a circulating high temperature environment in the middle period. Compared with the NC group, the ovarian LH level of the HT3 group was significantly reduced by 20.50% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on ovarian LH level.

[0124] In the later stage of the experiment, compared with the NC group, the ovarian LH level of the HC group was significantly reduced by 40.48% (P<0.01); compared with the HC group, the ovarian LH level of each HT group increased, and the ovarian LH level of the HT3 group increased the most, significantly increasing by 33.04% (P<0.01), indicating that in the later stage, 8 mg / kg of cantharidin can improve the ovarian LH level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the ovarian LH level of the HT3 group was significantly reduced by 20.81% (P<0.05), indicating that cantharidin partially alleviated the adverse effects of high temperature on ovarian LH levels.

[0125] (3) Effects of Cantharidin on E2 levels in the ovaries of Huaixiang breeder chickens in a cyclic high temperature environment

[0126] As shown in Table 8, in the early stage of the experiment, compared with the NC group, the ovarian E2 level of the HC group was significantly reduced by 45.15% (P<0.01); compared with the HC group, the ovarian E2 level of each HT group increased, among which the HT3 group had the largest increase, significantly increasing by 63.15% (P<0.01), indicating that the early addition of 8 mg / kg of cantharidin can improve the ovarian E2 level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the ovarian E2 level of the HT3 group decreased significantly by 10.52% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on the ovarian E2 level.

[0127] In the middle of the experiment, compared with the NC group, the ovarian E2 level of the HC group was significantly reduced by 42.64% (P<0.01); compared with the HC group, the ovarian E2 level of each HT group increased, among which the HT3 group increased the most by 52.99% (P<0.01), indicating that the addition of 8 mg / kg of cantharidin in the middle period can improve the ovarian E2 level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the ovarian E2 level of the HT3 group decreased significantly by 12.24% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on ovarian E2 level.

[0128] In the later stage of the experiment, compared with the NC group, the ovarian E2 level of the HC group was significantly reduced by 41.57% (P<0.01); compared with the HC group, the ovarian E2 level of each group increased, among which the ovarian E2 level of the HT3 group increased the most, significantly increasing by 67.91% (P<0.01), indicating that the addition of 8 mg / kg of cantharidin in the later stage can improve the ovarian E2 level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the ovarian E2 level of the HT3 group decreased by 1.90% (P>0.05), indicating that cantharidin can eliminate the adverse effects of high temperature on the ovarian E2 level, and the difference close to the normal temperature level was not significant.

[0129] In summary, cyclic high temperature reduced the ovarian E2 level of breeder chickens. In the same period, as the dosage of cantharidin increased, the ovarian E2 level of breeder chickens showed an upward trend. The optimal dose was 8 mg / kg in the early, middle and late stages. Based on the optimal doses of the early, middle and late stages, it can be seen that the optimal dose of cantharidin remained unchanged over time. As time went by, the ovarian E2 level of the optimal dose group increased from 506.59 pg / mL in the early stage to 549.30 pg / mL in the middle stage and then decreased to 536.57 pg / mL in the late stage, showing a trend of first increasing and then decreasing.

[0130] (4) Effects of Cantharidin on P4 levels in the ovaries of Huaixiang breeder chickens in a cyclic high temperature environment

[0131] As shown in Table 8, in the early stage of the experiment, compared with the NC group, the ovarian P4 level of the HC group was significantly reduced by 41.15% (P<0.01). Compared with the HC group, the ovarian P4 level of each HT group increased, among which the ovarian P4 level of the HT4 group increased the most, significantly increasing by 44.08% (P<0.05), indicating that the addition of 10 mg / kg of cantharidin in the early stage can improve the ovarian P4 level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the ovarian P4 level of the HT4 group was significantly reduced by 20.33% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on the ovarian P4 level.

[0132] In the middle of the experiment, compared with the NC group, the ovarian P4 level of the HC group was significantly reduced by 35.66% (P<0.05); compared with the HC group, the ovarian P4 level of each HT group increased, among which the ovarian P4 level of the HT3 group increased the most, significantly increasing by 44.96% (P<0.05), indicating that the addition of 8 mg / kg of cantharidin in the middle period can improve the ovarian P4 level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the ovarian P4 level of the HT3 group decreased by 6.74% (P>0.05), indicating that cantharidin can eliminate the adverse effects of high temperature on the ovarian P4 level, and the difference was not significant when it was close to the normal temperature level.

[0133] In the late stage of the experiment, compared with the NC group, the ovarian P4 level of the HC group was significantly reduced by 44.57% (P<0.05); compared with the HC group, the ovarian P4 level of each HT group increased, among which the ovarian P4 level of the HT3 group increased the most, significantly increasing by 56.67% (P<0.01), indicating that the addition of 8 mg / kg of cantharidin in the mid-term can improve the ovarian P4 level of breeder chickens in a circulating high temperature environment. Compared with the NC group, the ovarian P4 level of the HT3 group decreased by 13.15% (P<0.05), indicating that cantharidin cannot completely eliminate the adverse effects of high temperature on the ovarian P4 level.

[0134] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that are not conceived through creative work should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined in the claims.

Claims

1. A method for improving the egg-laying performance of Huaixiang chicken breeders under high temperature environment, characterized in that: Add canthaxanthin to feeding; The dosage of cantharidin is 8 mg / kg daily diet; cantharidin increases the number of follicles, SYF, LYF, SWF and LWF of Huaixiang chicken breeders; Cantharidin increased the serum FSH level, serum LH level, serum E2 level, and serum P4 level of Huaixiang chicken breeders; Cantharidin increases the ovarian FSH level and ovarian LH level of Huaixiang chicken breeders; increases the ovarian P4 level of Huaixiang chicken breeders.

2. The method according to claim 1, characterized in that: The specific steps are: divide Huaixiang chicken breeders into a normal temperature control group, a high temperature control group, and a high temperature treatment group, and randomly divide them into multiple groups for repetition. Add cantharidin to the diet and feed them for 28-36 weeks. Record the egg production rate, and then collect serum and ovarian homogenate to determine the effect of cantharidin on the egg production rate and follicle development of Huaixiang chicken breeders under high temperature environment.

3. The method according to claim 2, characterized in that: The egg-laying performance specifically includes: average daily feed intake, egg-laying rate, average egg weight, and soft egg rate.

4. The method according to claim 2, characterized in that: The temperature of the high temperature control group and the high temperature treatment group was 32±2°C; the temperature of the normal temperature control group was: 25±2°C.

5. The method according to claim 2, characterized in that: Cantharidin increased the average daily feed intake, egg production rate, average egg weight, and reduced the rate of soft-egg breakage of Huaixiang chicken breeders.

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