A method for supplementing pregnant sows with reverse double selenium sources in stages

Abstract

The application discloses a kind of pregnant sow stage reverse double selenium source supplementary feeding method, belong to livestock and poultry feed nutrition regulation technical field, including in the whole gestation period with basal diet as matrix supplementing constant selenium amount selenium, the selenium is provided by inorganic selenium premix and organic selenium premix, and inorganic selenium and organic selenium ratio is 3:7 in the middle of gestation, and the ratio is switched to 7:3 in the later period of gestation.The application adopts the above-mentioned pregnant sow stage reverse double selenium source supplementary feeding method, by adjusting the ratio of double selenium source in stages reversely, makes the selenium supplement method more suitable for the physiological needs of different stages of pregnancy under the premise of constant total selenium supplement level, improves the utilization efficiency of selenium nutrition, improves the sow antioxidant capacity and reproductive performance, improves the piglet selenium reserve and growth performance.The application is simple to operate, and can be directly used in the feed processing and feeding process of large-scale pig farm.

Description

Technical Field

[0001] This invention relates to the field of livestock and poultry feed nutrition regulation technology, and in particular to a method for staged reverse dual selenium source supplementation for pregnant sows. Background Technology

[0002] Selenium is an essential trace element for animal organisms and an important component of various selenoproteins. It plays a vital role in antioxidant regulation, maintaining immune homeostasis, ensuring reproductive performance, and in embryonic and fetal development. For pregnant sows, the maternal selenium nutritional status not only affects their own health and reproductive performance but also influences placental nutrient transport, selenium reserves in newborn piglets, and early growth and antioxidant capacity after birth.

[0003] Currently, selenium supplementation in pregnant sows involves using either single-source inorganic or single-source organic selenium, or a combination of inorganic and organic selenium to balance cost and bioavailability. Specifically, a certain amount of selenium is added to the basal diet of pregnant sows, provided by sodium selenite and yeast selenium in a fixed ratio that remains constant throughout the gestation period. Selenium supplementation programs typically focus on the formula itself, the composition of premixes, or fortification during late gestation. In production, the selenium source is premixed and added to the complete feed, starting after mating confirmation of pregnancy and continuing until farrowing.

[0004] However, current selenium supplementation methods only use a single, fixed ratio of two selenium sources, failing to differentiate the nutritional needs of pregnant sows at different physiological stages. Specifically, from mating to day 85 of gestation, sows mainly undergo embryo implantation, placental establishment, and maternal nutrient reserves. During this stage, organic selenium has unique advantages in placental transport and accumulation in embryonic tissues. From day 86 of gestation to farrowing, sows enter a period of rapid fetal growth and farrowing preparation, during which immune load and metabolic stress increase. Inorganic selenium is effective in rapidly increasing glutathione peroxidase activity. Current selenium supplementation methods maintain a constant ratio of sodium selenite to yeast selenium throughout gestation, failing to fully utilize the tissue deposition advantages of organic selenium in the early and mid-stages of gestation, and also failing to fully utilize the rapid antioxidant regulatory effects of inorganic selenium in late gestation. This results in insufficient matching of selenium supplementation programs with the physiological processes of different stages of gestation, limiting the utilization of selenium nutrition.

[0005] Therefore, there is an urgent need to propose a more targeted method for staged reverse dual-source selenium supplementation in pregnant sows to address the problems of insufficient consideration of the correspondence between differences in pregnancy stages, differences in selenium source characteristics, and stage-appropriate supplementation in existing selenium supplementation methods, as well as the inadequate matching degree between selenium supplementation programs and the physiological processes of pregnancy. Summary of the Invention

[0006] The purpose of this invention is to provide a method for staged reverse dual-selenium supplementation for pregnant sows to solve the above-mentioned problems.

[0007] This invention provides a method for staged reverse dual-selenium source supplementation for pregnant sows. Throughout the entire gestation period, a constant total selenium content is supplemented using the basal diet as a substrate. The selenium includes an inorganic selenium premix and an organic selenium premix. The inorganic and organic selenium premixes are mixed with a carrier to prepare a composite selenium source premix, which is then added to the basal diet. In the early and mid-gestation periods, the ratio of selenium provided by the inorganic selenium premix to that provided by the organic selenium premix is ​​3:7; in the late gestation period, the ratio of selenium provided by the inorganic selenium premix to that provided by the organic selenium premix is ​​7:3.

[0008] Preferably, the total selenium content is constant at 0.5 mg / kg.

[0009] Preferably, during the first and second trimesters of pregnancy, the inorganic selenium premix provides 0.15 mg / kg of selenium, and the organic selenium premix provides 0.35 mg / kg of selenium; during the third trimester of pregnancy, the inorganic selenium premix provides 0.35 mg / kg of selenium, and the organic selenium premix provides 0.15 mg / kg of selenium.

[0010] Preferably, the inorganic selenium premix is ​​a feed-grade selenium premix using sodium selenite as the selenium source, and the organic selenium premix is ​​a feed-grade yeast selenium.

[0011] Preferably, the effective selenium content of the inorganic selenium premix is ​​0.5% to 5.0%, more preferably 1.0%; the effective selenium content of the organic selenium premix is ​​0.1% to 0.5%, more preferably 0.2%; the effective selenium content is based on the value indicated on the product label or the actual test value.

[0012] Preferably, the carrier is wheat bran, and the inorganic selenium premix and the organic selenium premix are thoroughly mixed with wheat bran to obtain a composite selenium source premix.

[0013] Preferably, based on 100 parts of the total weight of the composite selenium source premix, the total amount of inorganic selenium premix and organic selenium premix is ​​0.1 to 10 parts, the amount of wheat bran is 90 to 99.9 parts, the total amount of inorganic selenium premix and organic selenium premix is ​​preferably 1 to 5 parts, and the amount of wheat bran is preferably 95 to 99 parts.

[0014] Preferably, the switching time between the early and mid-pregnancy period and the late pregnancy period is set between the 80th and 90th day of pregnancy.

[0015] Therefore, the present invention employs the above-described method for staged reverse dual-selenium source supplementation in pregnant sows, which has the following beneficial effects: (1) Under the premise of keeping the total selenium supplementation level constant at 0.5 mg / kg, organic selenium is mainly used in the early and mid-pregnancy period, i.e., the embryo implantation and placental establishment period, taking advantage of its high deposition rate and easy passage through the placenta; inorganic selenium is mainly used in the late pregnancy period, i.e., the rapid growth period of the fetus, taking advantage of its ability to rapidly increase glutathione peroxidase activity. By switching the ratio in reverse, the selenium nutrient supply can be precisely adapted to the physiological needs of different stages. At the same time, organic selenium is mainly used in the early and mid-pregnancy period to give full play to its high bioavailability; inorganic selenium is mainly used in the late pregnancy to take advantage of its low cost and wide availability. The phased combination of the two can control feed costs while ensuring the effect, and improve the overall economic efficiency of the dual selenium source supplementation program.

[0016] (2) Without changing the total selenium supplementation level, the absorption, metabolism and deposition efficiency of selenium can be optimized by adjusting the proportion in stages, avoiding the increased cost or potential toxicity risks caused by blindly increasing the amount added. This method only requires switching between two different selenium source ratios in the feed around the 85th day of gestation, without changing the basic diet formula and routine feeding management process. No special equipment or additional labor input is required, making it easy to apply directly in large-scale production.

[0017] (3) By supplementing selenium in stages, the maternal selenium nutritional status is improved, the placental selenium transport efficiency and the selenium content in colostrum / normal milk are increased, thereby increasing the selenium reserves in the piglets' liver and blood at birth, which helps to enhance the piglets' antioxidant capacity and growth performance after birth.

[0018] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0019] To better understand the above technical solutions, a detailed description of the specific implementation methods will be provided below. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0021] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0022] This invention provides a method for staged reverse dual-selenium source supplementation for pregnant sows. Throughout the entire gestation period, a constant total selenium content is supplemented into the basal diet, which includes an inorganic selenium premix and an organic selenium premix. The inorganic and organic selenium premixes are thoroughly mixed with wheat bran to prepare a composite selenium source premix, which is then added to the basal diet. Based on 100 parts of the total weight of the composite selenium source premix, the total amount of the inorganic and organic selenium premixes is 0.1 to 10 parts, and the amount of wheat bran is 90 to 99.9 parts.

[0023] The total selenium content is constant at 0.5 mg / kg. During the first and second trimesters of pregnancy, the ratio of selenium provided by the inorganic selenium premix to that provided by the organic selenium premix is ​​3:7; that is, the inorganic selenium premix provides 0.15 mg / kg of selenium, and the organic selenium premix provides 0.35 mg / kg of selenium. During the third trimester of pregnancy, the ratio of selenium provided by the inorganic selenium premix to that provided by the organic selenium premix is ​​7:3; that is, the inorganic selenium premix provides 0.35 mg / kg of selenium, and the organic selenium premix provides 0.15 mg / kg of selenium. The inorganic selenium premix is ​​a feed-grade selenium premix using sodium selenite as the selenium source, and the organic selenium premix is ​​a feed-grade yeast selenium premix. The effective selenium content of the inorganic selenium premix is ​​0.5%–5.0%; the effective selenium content of the organic selenium premix is ​​0.1%–0.5%; the effective selenium content is based on the value indicated on the product label or the actual measured value. The period from mating to the 85th day of pregnancy is considered the first and second trimesters, while the period from the 85th day of pregnancy to delivery is considered the third trimester.

[0024] This invention maintains a constant total selenium supplementation level of 0.5 mg / kg, and adjusts the ratio of inorganic to organic selenium supply in reverse according to the physiological characteristics of pregnant sows at different stages. Its mechanism of action is as follows: During the early to mid-pregnancy period, from mating to day 85 of gestation, organic selenium is the primary source of nutrients. This stage is crucial for embryo implantation, placental formation, and maternal nutrient reserves. Selenium in yeast selenium primarily exists in the form of selenomethionine, which has the same absorption pathway as methionine, high bioavailability, and is easily transported across the placenta to the fetus, accumulating in embryonic tissues and providing ample selenium reserves for early fetal development. Simultaneously, selenomethionine can non-specifically integrate into body proteins, forming a selenium reserve that can be released and utilized later in pregnancy or during lactation when needed. Therefore, increasing the proportion of organic selenium (70%) during this stage helps ensure embryonic development and placental function, and improves the selenium nutritional levels of both the mother and fetus.

[0025] During the late stages of pregnancy, from day 86 to delivery, inorganic selenium is the primary source of nutrients. At this stage, the fetus enters a period of rapid growth, and the maternal metabolic load and oxidative stress levels increase significantly. Sodium selenite exists as an inorganic salt, and after absorption, it is rapidly converted into selenoproteins with antioxidant activity primarily through the glutathione peroxidase (GSH-Px) synthesis pathway. This can rapidly enhance the GSH-Px activity in maternal blood and tissues, effectively scavenging lipid peroxides and alleviating perinatal oxidative stress. Furthermore, inorganic selenium is less expensive, and using it as the primary selenium source at this stage can control feed costs while ensuring antioxidant effects.

[0026] Organic selenium's reserve function is suitable for the early stages of pregnancy. During the early and mid-stages, selenium reserves are needed for the entire pregnancy and lactation period, and the slow-release properties of organic selenium better meet this need. Inorganic selenium's immediate function is suitable for the later stages, when rapid response to oxidative stress and the rapidly growing selenium requirements of the fetus are needed. Inorganic selenium is converted into selenoproteins more quickly. Maintaining a total selenium supplementation level of 0.5 mg / kg, which is near the upper limit of the NRC recommended range, can meet the needs of high-producing sows without increasing selenium supplementation costs. By reversing the ratio of "organic before inorganic," a precise match between selenium nutrition supply and the physiological needs of the pregnancy stage is achieved. This optimizes selenium absorption, metabolism, and utilization efficiency without increasing the total selenium dosage, thereby improving the selenium nutritional status and antioxidant capacity of sows and piglets.

[0027] To more clearly and in detail introduce the method for staged reverse dual-selenium source supplementation for pregnant sows provided by the present invention, the following description will be based on specific embodiments and comparative examples.

[0028] Example 1 A method for staged reverse dual-selenium supplementation in pregnant sows is implemented according to the following steps: Thirty healthy sows that had completed mating and confirmed pregnancy were selected and fed a standard complete feed for pregnant sows as their base diet.

[0029] Preparation of selenium source premixes: Inorganic selenium premixes use feed-grade sodium selenite as the selenium source, with an effective selenium content of 1.0%. Organic selenium premixes use feed-grade yeast selenium, with an effective selenium content of 0.2%. The above effective selenium content is subject to the value indicated on the product label.

[0030] Preparation of the composite selenium source premix: Inorganic selenium premix and organic selenium premix are thoroughly mixed with wheat bran to obtain the composite selenium source premix. Based on a total weight of 100 kg of the composite selenium source premix, the total amount of inorganic and organic selenium premix used is 2 kg, and the amount of wheat bran used is 98 kg.

[0031] Formulate phased feeds: According to the different needs of the early and mid-pregnancy period (from mating to day 85 of gestation) and the late pregnancy period (day 86 of gestation to farrowing), add the above-mentioned compound selenium source premix to the complete compound feed for pregnant sows and mix evenly to formulate early and mid-pregnancy feeds and late pregnancy feeds respectively.

[0032] During the first and second trimesters of pregnancy, the inorganic selenium premix provides 0.15 mg / kg of selenium, while the organic selenium premix provides 0.35 mg / kg of selenium. The ratio of inorganic to organic selenium is 30:70, and the total selenium content is 0.5 mg / kg.

[0033] In late pregnancy, the inorganic selenium premix provides 0.35 mg / kg of selenium, the organic selenium premix provides 0.15 mg / kg of selenium, the ratio of inorganic selenium to organic selenium is 70:30, and the total selenium content is 0.5 mg / kg.

[0034] Feeding and Management: The compound selenium source premix was added to the basal diet in a stepwise expansion mixing manner and mixed evenly. Two-stage feeds were prepared according to the above-mentioned addition amount. All sows were housed in individual pens with free access to water.

[0035] In this embodiment, the switching date from pre- and mid-gestation feed to late-gestation feed is day 85 of gestation. That is, the pre- and mid-gestation feed is fed from mating to day 85, and the late-gestation feed is switched from day 86 onwards. Depending on production needs, the switching date can also be any day between day 80 and day 90 of gestation, such as day 82 or day 88.

[0036] Other feeding and management practices, such as immunization, disinfection, and farrowing, are carried out according to the standard procedures of the pig farm.

[0037] Comparative Example 1 The following is a complete organic selenium supplementation program: The preparation method of the selenium source and selenium source premix is ​​the same as in Example 1, but only organic selenium premix, namely yeast selenium, is used throughout the gestation period, and no inorganic selenium premix is ​​added. Based on the effective selenium content, the total amount of organic selenium supplemented in the basal diet is kept constant at 0.5 mg / kg. No feed switching is performed throughout the gestation period; the same diet is fed continuously. All other operations are the same as in Example 1.

[0038] Comparative Example 2 The entire process of inorganic selenium supplementation is adopted, as detailed below: The preparation method of the selenium source and selenium source premix is ​​the same as in Example 1, but only the inorganic selenium premix, i.e., sodium selenite, is used throughout the entire gestation period; no organic selenium premix is ​​added. Based on the effective selenium content, the total amount of inorganic selenium supplemented in the basal diet is kept constant at 0.5 mg / kg. No feed changes are made throughout the gestation period; the same diet is fed continuously. All other operations are the same as in Example 1.

[0039] The following samples were collected and measured from the sows of Example 1 and Comparative Examples 1-2: On day 85 of gestation and 24 hours postpartum, 10 mL of fasting blood was collected from sows via the anterior vena cava. The blood was placed in vacuum blood collection tubes without anticoagulants, allowed to stand at room temperature for 30 minutes, and then centrifuged at 3000 rpm for 15 minutes to separate the serum. The serum was aliquoted into cryovials and stored at -20°C for later analysis. The collected sow serum samples were used to determine the following indicators: serum selenium concentration was determined by atomic fluorescence spectrometry or inductively coupled plasma mass spectrometry, expressed in μg / L; glutathione peroxidase (GSH-Px) activity was determined by the dithiodinitrobenzoic acid colorimetric method, expressed in U / mL; total antioxidant capacity (T-AOC) was determined by the ferric reduction method or ABTS free radical scavenging method, expressed in U / mL; malondialdehyde (MDA) content was determined by the thiobarbituric acid method, expressed in nmol / mL; and reactive oxygen species (ROS) levels were determined by chemiluminescence or fluorescent probe methods. The results are shown in Table 1 below.

[0040] Table 1. Effects of different selenium supplementation regimens on serum antioxidant indices in pregnant sows.

[0041] Comparative Example 1 showed higher serum selenium concentrations at 85 days of gestation and within 24 hours postpartum, indicating that yeast selenium has good in vivo deposition characteristics. Example 1 showed serum selenium levels close to Comparative Example 1 at 85 days of gestation, suggesting that increasing the proportion of yeast selenium in the early and mid-stages of gestation is beneficial for maintaining maternal selenium reserves. Regarding antioxidant indicators within 24 hours postpartum, Example 1 showed higher levels of GSH-Px and T-AOC, and lower levels of MDA and ROS. These results indicate that increasing the proportion of sodium selenite in late gestation helps enhance the activity of the sow's antioxidant enzyme system and reduce lipid peroxidation and reactive oxygen species levels. Therefore, Example 1 can provide good nutritional support for the progressive oxidative stress in late gestation while maintaining the maternal selenium nutritional status.

[0042] Milk samples were collected from sows within 24 hours postpartum (colostrum), on day 7 of lactation, and on day 21 of lactation. Before collection, the sow's udder was washed with warm water and dried. Approximately 20 mL of milk was manually expressed into sterile centrifuge tubes and centrifuged at 3000 rpm for 10 minutes. After removing the fat layer, the whey fraction was aliquoted, frozen, and stored at -20°C for analysis. The milk samples were used to determine the selenium concentrations in colostrum, selenium in normal milk at day 7 of lactation, and selenium in normal milk at day 21 of lactation. The determination method was the same as for serum selenium, and the units are expressed in μg / L. The results are shown in Table 2 below.

[0043] Table 2. Effects of different selenium supplementation regimens on selenium content in sow milk.

[0044] Comparative Example 1 showed high selenium content in colostrum, milk from 7 days of lactation, and milk from 21 days of lactation, consistent with the characteristic that organic selenium is more easily deposited and transferred through milk. Example 1 showed lower selenium content in milk than Comparative Example 1, but significantly higher than Comparative Example 2, indicating that Example 1, even with a higher proportion of yeast selenium in the early and mid-pregnancy stages, still maintained a good level of selenium transfer in milk. Therefore, Example 1 did not simply aim for the highest selenium content in milk, but rather, while maintaining a good level of selenium in milk, increased the proportion of selenium from sodium selenite in late pregnancy, thus addressing both the antioxidant needs of sows in late pregnancy and the selenium nutrition supply to piglets in early pregnancy.

[0045] Two newborn piglets (half male and half female) of similar weight from each litter were selected. 5 mL of blood was collected from the anterior vena cava immediately after birth and before the piglets consumed colostrum. Serum was separated and used to determine the serum selenium concentration of the newborn piglets, expressed in μg / L. After blood collection, the piglets were euthanized, and approximately 5 g of liver tissue was collected. The liver tissue was rinsed with physiological saline to remove blood, blotted dry with filter paper, and then aliquoted and frozen. The liver selenium content was determined using atomic fluorescence spectrometry or inductively coupled plasma mass spectrometry, expressed in mg / kg. At 21 days of age, two piglets (half male and half female) from the same litter as at birth were selected again, and 5 mL of blood was collected from the anterior vena cava. Serum was separated, and the serum selenium concentration of the 21-day-old piglets was determined, expressed in μg / L. The results are shown in Table 3 below.

[0046] Table 3. Effects of different selenium supplementation regimens on the selenium nutritional status of piglets.

[0047] Comparative Example 1 showed higher levels of selenium in the serum of newborn piglets, liver of newborn piglets, and serum of 21-day-old piglets, indicating that yeast selenium has certain advantages in selenium transfer between the mother and piglets and selenium deposition in piglets. Although the selenium nutritional indicators of piglets in Example 1 were slightly lower than those in Comparative Example 1, they were all significantly higher than those in Comparative Example 2. This shows that increasing the proportion of selenium from yeast selenium sources in Example 1 during the early and mid-stages of gestation helps in the formation of maternal selenium reserves and provides a better selenium nutritional foundation for piglets during birth and early lactation. Furthermore, switching to a higher proportion of sodium selenite in late gestation did not significantly weaken the selenium nutritional status of piglets, indicating that this phased switching method is feasible.

[0048] At farrowing, the total number of piglets born, the number of live piglets, and the number of healthy piglets (healthy piglets are defined as those with a birth weight of not less than 0.8 kg, no deformities, and normal vitality) were recorded for each litter. Simultaneously, the birth weight of each piglet was weighed, and the litter weight at birth was calculated. At weaning at 21 days of age, each piglet was weighed again, and the 21-day-old piglet weight and litter weight were recorded. The average daily weight gain during lactation was calculated based on the birth weight and 21-day-old weight using the formula: (21-day-old weight - birth weight) ÷ 21 × 1000, expressed in g / d. The number of piglets that died between birth and weaning at 21 days of age was also recorded, and the lactation mortality rate was calculated using the formula: (number of dead piglets ÷ number of live piglets) × 100%. All biochemical indicators were measured using commercially available kits, following the instructions, using an ELISA reader or spectrophotometer. Two parallel samples were prepared for each sample, and the average value was taken as the result. The results are shown in Table 4 below.

[0049] Table 4. Effects of different selenium supplementation regimens on sow reproductive performance and piglet growth performance.

[0050] Example 1 and Comparative Examples 1-2 showed little difference in total litter size, live litter size, and piglet birth weight, indicating that the effects of different selenium source treatments on basic reproductive performance were relatively limited. Example 1 showed better performance in terms of healthy piglet count, birth litter weight, 21-day-old piglet weight, 21-day-old litter weight, and daily weight gain during lactation. This phased dual-selenium source supplementation method is beneficial for improving piglet growth performance during lactation. In terms of health indicators, Example 1 showed lower rates of diarrhea and mortality during lactation, and higher survival rates. Combining the antioxidant indicators and milk selenium results of sows 24 hours after farrowing, Example 1 improved the health status and growth performance of piglets during lactation by maintaining maternal selenium reserves in the early and mid-pregnancy stages and alleviating oxidative stress in the late pregnancy stages. In summary, Example 1 demonstrates a comprehensive advantage over the single organic or single inorganic selenium supplementation methods used in Comparative Examples 1-2 throughout the entire lactation period.

[0051] Therefore, this invention employs the aforementioned method of phased reverse dual-selenium supplementation for pregnant sows. While maintaining a constant total selenium supplementation level of 0.5 mg / kg, organic selenium is primarily used during the early to mid-pregnancy period (embryo implantation and placental establishment), leveraging its high deposition rate and easy placental passage. During the late pregnancy period (rapid fetal growth), inorganic selenium is primarily used, utilizing its advantage of rapidly increasing glutathione peroxidase activity. By switching the proportions in reverse, selenium nutrient supply is precisely tailored to the physiological needs of different stages. Simultaneously, the use of organic selenium during the early to mid-pregnancy period fully utilizes its high bioavailability, while the use of inorganic selenium during the late pregnancy leverages its low cost and wide availability. This phased combination of both methods ensures effectiveness while controlling feed costs, thus improving the overall economic efficiency of the dual-selenium supplementation program.

[0052] Without changing the total selenium supplementation level, the absorption, metabolism, and deposition efficiency of selenium can be optimized through phased ratio adjustments, avoiding increased costs or potential toxicity risks from blindly increasing the amount added. This method only requires switching between two different selenium source ratios in the feed around day 85 of gestation, without changing the basic diet formula or routine feeding management procedures. No special equipment or additional labor is required, making it easy to apply directly in large-scale production. By supplementing selenium in stages, the maternal selenium nutritional status is improved, increasing placental selenium transport efficiency and selenium content in colostrum / regular milk, thereby increasing selenium reserves in the liver and blood of newborn piglets, which helps enhance the antioxidant capacity and growth performance of piglets after birth.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for staged reverse dual-selenium source supplementation in pregnant sows, characterized in that, Throughout the sow's gestation period, a constant total selenium content is supplemented into the basal diet, which includes both inorganic and organic selenium premixes. The inorganic and organic selenium premixes are mixed with a carrier to prepare a composite selenium source premix, which is then added to the basal diet. During the early and mid-gestation periods, the ratio of selenium provided by the inorganic to organic selenium premixes is 3:7; during late gestation, the ratio is 7:

3.

2. The method for staged reverse dual-selenium source supplementation in pregnant sows according to claim 1, characterized in that, The total selenium content is constant at 0.5 mg / kg.

3. The method for staged reverse dual-selenium source supplementation in pregnant sows according to claim 1, characterized in that, During the first and second trimesters of pregnancy, the inorganic selenium premix provides 0.15 mg / kg of selenium, while the organic selenium premix provides 0.35 mg / kg. During the third trimester of pregnancy, the inorganic selenium premix provides 0.35 mg / kg of selenium, while the organic selenium premix provides 0.15 mg / kg.

4. The method for staged reverse dual-selenium source supplementation in pregnant sows according to claim 1, characterized in that, The inorganic selenium premix is ​​a feed-grade selenium premix with sodium selenite as the selenium source, and the organic selenium premix is ​​a feed-grade yeast selenium premix.

5. The method for staged reverse dual-selenium source supplementation in pregnant sows according to claim 1, characterized in that, The effective selenium content of the inorganic selenium premix is ​​0.5% to 5.0%; the effective selenium content of the organic selenium premix is ​​0.1% to 0.5%.

6. The method for staged reverse dual-selenium source supplementation in pregnant sows according to claim 1, characterized in that, The carrier is wheat bran. The inorganic selenium premix and the organic selenium premix are thoroughly mixed with wheat bran to obtain a composite selenium source premix.

7. The method for staged reverse dual-selenium source supplementation in pregnant sows according to claim 1, characterized in that, Based on a total weight of 100 parts of the compound selenium source premix, the total amount of inorganic selenium premix and organic selenium premix is ​​0.1 to 10 parts, and the amount of wheat bran is 90 to 99.9 parts.

8. The method for staged reverse dual-selenium source supplementation in pregnant sows according to claim 1, characterized in that, The transition time between the early and mid-pregnancy period and the late pregnancy period is set between the 80th and 90th day of pregnancy.

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