Feeding method for Yunong black pigs in fattening period

Abstract

The invention belongs to the technical field of animal feeding, and particularly relates to a feeding method for Yunong black pigs in the fattening period. The method includes the following steps that the fattening period of the Yunong black pigs is divided into three stages according to the weights of the Yunong black pigs, and the three stages are the fattening earlier stage, the fattening middle stage and the fattening later stage; fitting to obtain a precise protein demand quantity model; screening to obtain the preliminary protein demand amount of the Yunong black pigs in the later stage of fattening, and determining the precise protein demand amount of the Yunong black pigs in the later stage of fattening; according to the precise protein demand amount of the Yunong black pigs in the late fattening period, a daily ration formula is determined, daily ration is prepared, and feeding is conducted. According to the feeding method for the Yunong black pigs in the fattening period, the optimal additive amount of protein of the Yunong black pigs in the fattening period (75-100 kg) is explored through animal feeding, digestion and metabolism tests, slaughtering tests and the like, the feeding method for the Yunong black pigs in the fattening period is provided, the using amount of soybean meal in feed is reduced by adding low-protein daily ration, and then the feeding cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of animal husbandry technology, specifically relating to a feeding method for Henan black pigs during the fattening period. Background Technology

[0002] In recent years, with consumers' increasing demands for pork quality, the breeding of local pig breeds in my country has ushered in new opportunities. my country's local pig breeds are abundant, have low lean meat percentages and slow weight gain, but their pork is of high quality and has distinctive characteristics, possessing a huge potential market. However, current research on the nutritional needs of my country's local pigs is limited, and relevant feeding standards are lacking.

[0003] Protein is an essential nutrient for animals and a raw material in livestock and poultry feed that directly affects feed costs. Yu Nong Black Pig, a high-quality and efficient black pig breed newly developed by our team based on local Henan pig breeds, is characterized by strong reproductive capacity, robust physique, tolerance to roughage, stress resistance, and excellent meat quality. However, in current production, the protein requirements in feed formulations are mainly based on the nutritional requirements of imported pig breeds such as Landrace and Large White. This borrowed formulation does not fully match the actual nutritional needs of the new Yu Nong Black Pig breed. Currently, there are no reports on the optimal protein requirements for the fattening period of the new Yu Nong Black Pig breed. Therefore, research on feeding methods for the fattening period of Yu Nong Black Pig is urgently needed. Summary of the Invention

[0004] To conduct research on the feeding methods of Yuzhong Black Pigs during the fattening period and to address the lack of reports in existing technologies regarding the optimal protein requirements of the feed for the new breed of Yuzhong Black Pigs during the fattening period, this invention provides a feeding method for Yuzhong Black Pigs during the fattening period. To achieve the above objective, this invention adopts the following technical solution.

[0005] The purpose of this invention is to conduct research on the feeding methods of Yuzhong Black Pigs during the fattening period, and to provide a feeding method for Yuzhong Black Pigs during the fattening period, including the following steps: Feeding pigs in stages according to their body weight during the fattening period is one of the core technologies of modern scientific pig farming. The fundamental reason for this is that pigs have different physiological characteristics, nutritional needs, and growth priorities at different growth stages. This refined management approach can maximize growth performance, improve feed utilization efficiency, reduce feeding costs, and ensure the health of the pig herd.

[0006] Therefore, based on the weight of the Yu Nong Black Pig, the fattening period of the Yu Nong Black Pig is divided into three stages: early fattening stage: 25kg~50kg, middle fattening stage: 50kg~75kg, and late fattening stage: 75kg~100kg.

[0007] In the late fattening stage (75kg to slaughter, the high-weight stage): During this stage, the pig's muscle growth rate slows significantly, while its fat deposition capacity greatly increases. Energy requirements reach their peak to support substantial fat synthesis. Protein requirements decrease significantly. Continuing to use the high-protein feed from the earlier stage not only wastes expensive protein resources (excess protein is deaminated and converted into energy, which is inefficient and increases the burden on the liver and kidneys), but also limits fat deposition due to insufficient energy, affecting weight gain and backfat thickness at slaughter. The Yu Nong Black Pig is a new breed developed by Henan Agricultural University in conjunction with pig farms. It features strong reproductive capacity, robust physique, tolerance to roughage, stress resistance, and excellent meat quality. However, its current nutritional requirements still rely on standards from exogenous pig breeds (such as Landrace and Large White pigs).

[0008] Dietary formulations with different gradient protein levels were developed and fed to multiple late-stage fattening Yu Nong Black Pigs to obtain parameters such as daily weight gain, feed conversion ratio, and different traits; among which, different traits included body size traits, carcass traits, and meat quality.

[0009] Based on the parameters of daily weight gain, feed conversion ratio, and protein level corresponding to diet formulations with different gradient protein levels, a precise protein requirement model is fitted. Then, based on the precise protein requirement model, the protein level corresponding to the optimal daily weight gain and feed conversion ratio parameters of Yuzhong black pigs in the late fattening stage is selected, and the preliminary protein requirement of Yuzhong black pigs in the late fattening stage is screened. The precise protein requirement model includes the fitted curve of daily weight gain and the fitted curve of feed conversion ratio of Yuzhong black pigs in the late fattening stage.

[0010] The optimal protein levels in the diet formulations corresponding to the parameters of body size, carcass traits, and meat quality were selected. The optimal body size trait was defined as the lowest backfat thickness (17.30mm ± 4.83mm) and the deepest eye muscle depth (44.84mm ± 8.15mm) among live Yu Nong Black Pigs. The optimal carcass traits were defined as the highest lean meat percentage (60.69% ± 8.98%) and the largest eye muscle area (3949.52mm²) among Yu Nong Black Pigs. 2 ±616.80mm 2 The optimal conditions for meat quality are the highest pH value (a core indicator for meat preservation) within 24 hours, and the lowest shear force (the best tenderness).

[0011] Based on the preliminary protein requirements of Yu Nong Black Pigs in the later stages of fattening, and combined with the protein levels in the diet formulas corresponding to the parameters of optimal body size, carcass traits, and meat quality, the precise protein requirements of Yu Nong Black Pigs in the later stages of fattening are determined.

[0012] Based on the precise protein requirements of the Yu Nong Black Pigs in the later stages of fattening, the diet formula was determined, the diet was prepared, and the pigs were fed.

[0013] This invention aims to study the feeding methods of Yuzhong Black Pigs during their fattening period and provides a feeding method for these pigs. By constructing fitting curves for the daily weight gain and feed conversion ratio of Yuzhong Black Pigs in the later fattening stage, this invention establishes a precise protein requirement model, determines the optimal protein supplementation range during the fattening period (75kg~100kg), and formulates an optimal low-protein diet formula that meets the growth needs of Yuzhong Black Pigs. This provides a feeding method for Yuzhong Black Pigs during their fattening period (75kg~100kg). Based on the breed characteristics of Yuzhong Black Pigs (body size traits, carcass traits, and meat quality in the later fattening stage) and a precise growth model (precise protein requirement model), this method significantly reduces the crude protein level in the diet (compared to NRC standards or conventional empirical formulas) while precisely meeting their protein requirements at specific growth stages. This effectively solves the problem of inaccurate protein addition caused by the reliance on general models or empirical formulas in traditional methods. While maintaining or even improving the growth performance (daily weight gain) and feed conversion efficiency (feed to weight ratio) of Yuzhong black pigs, it significantly reduces the amount of expensive protein raw materials (soybean meal) in the feed, significantly reduces feed costs, and reduces nitrogen emissions, thus alleviating environmental pollution pressure.

[0014] Furthermore, the precise protein requirement model includes a fitting curve for the daily weight gain of Yuzhong Black Pigs in the late fattening stage and a fitting curve for the feed conversion ratio of Yuzhong Black Pigs in the late fattening stage; the fitting result of the fitting curve for the daily weight gain of Yuzhong Black Pigs in the late fattening stage is: y = -0.0208x 2 +0.5072x-2.4418 (R²=0.9963), where y is the daily weight gain and x is the protein level; the fitted curve of the feed conversion ratio of Yu Nong Black Pigs in the late fattening stage is: y=0.1208x 2 -2.8843x+20.681 (R²=0.8589), where y is the daily weight gain and x is the protein level.

[0015] Furthermore, the initial protein requirement for Yu Nong Black Pigs in the later stages of fattening is 11.94% to 12.2%. The initial protein requirement of 11.94% for Yu Nong Black Pigs in the later stages of fattening is determined by selecting the protein level corresponding to the optimal daily weight gain parameter based on the fitted curve of the daily weight gain of Yu Nong Black Pigs in the later stages of fattening. The initial protein requirement of 12.2% for Yu Nong Black Pigs in the later stages of fattening is determined by selecting the protein level corresponding to the optimal feed conversion ratio parameter based on the fitted curve of the feed conversion ratio of Yu Nong Black Pigs in the later stages of fattening.

[0016] Furthermore, the optimal protein level in the diet corresponding to the parameters of body size, carcass traits, and meat quality was 11%. Specifically: 1) The protein level in the diet corresponding to the lowest backfat thickness (17.30mm±4.83mm) and the deepest eye muscle depth (44.84mm±8.15mm) of the Yuzhong Black Pig was selected, resulting in a protein level of 11% (the backfat thickness measured at 11% protein level was significantly lower than other protein level groups by 18.6%~23.7%, while the eye muscle depth was excellent, significantly better than the high-protein group (14.76% at 40.78mm) and the low-protein group (10.4% at 40.83mm)). 2) The highest lean meat percentage (60.69%±8.98%) and the largest eye muscle area (3949.52mm) of the Yuzhong Black Pig were selected among the carcass traits. 2 ±616.80mm 2 The protein level in the diet under the specified parameters (conditions) was determined to be 11% (the lean meat percentage measured at the 11% protein level was significantly higher than the 50.63% in the 13% group). P The percentage of positive ocular muscle tissue was ≤0.05, which was 2.14% higher than the second-best group (10.4% to 58.55%); at the same time, the ocular muscle area was the largest, significantly higher than all other groups by 39% to 41%. P ≤0.05). 3) Select the protein level in the diet corresponding to the parameter (condition) with the highest 24-hour pH value (the core indicator of meat preservation) and the lowest meat shear force (the best meat tenderness). The protein level in the diet was found to be 11% (the 24-hour pH value of the meat measured at the 11% protein level was 5.56±0.11, which was significantly higher than the 5.31 of the 14.76% group). P ≤0.05 (pH>5.4 effectively inhibits dripping water loss), indicating better water retention at this level; simultaneously, at the 11% protein level, the meat exhibited the lowest shear force, 44.02±3.74 N, which was 25.6%~34.3% lower than all other groups. P ≤0.05 indicates that the meat has the best tenderness at this level.

[0017] Furthermore, the different protein levels in the dietary formulations with different protein gradients are different values ​​selected within the range of 10% to 14%. Specifically, the values ​​are 10%, 11%, 12%, 13%, and 14%, respectively.

[0018] Furthermore, the precise protein requirement of the Yu Nong Black Pig in the later stage of fattening is obtained by combining the preliminary protein requirement of the Yu Nong Black Pig in the later stage of fattening with the protein level in the diet formula corresponding to the optimal body size traits, carcass traits and meat quality parameters, taking the intersection and removing the decimal points, and obtaining a numerical index with only integers.

[0019] Furthermore, the precise protein requirement of the Yuzhong Black Pig after fattening is 11%-12%. This is a numerical indicator with only integers obtained by combining the preliminary protein requirement of the Yuzhong Black Pig in the later stage of fattening with the protein level in the diet corresponding to the body size, carcass, and meat quality parameters, taking the intersection value, and removing the decimal part of the value.

[0020] Furthermore, the diet formula is obtained based on the precise protein requirements of the Yu Nong Black Pigs in the later stages of fattening.

[0021] The diet, by weight, is made from the following ingredients: 70.1 to 72.4 parts corn, 2.685 to 5.2 parts high-fat DDGS, 3.35 to 7 parts soybean meal, 15.38 to 17.08 parts wheat bran, 0.05 parts ethoxyquinoline, 0.05 parts preservative, 0.02 parts enzyme preparation, 3.5 parts premix, 0.29 to 0.355 parts lysine, 0.13 to 0.17 parts threonine, 0.03 to 0.05 parts methionine, 0.05 to 0.055 parts tryptophan, and 0.15 to 0.19 parts valine.

[0022] Further, the diet, by weight, is made from the following ingredients: 70.1 parts corn, 5.2 parts high-fat DDGS, 3.35 parts soybean meal, 17.08 parts wheat bran, 0.05 parts ethoxyquinoline, 0.05 parts preservative, 0.02 parts enzyme preparation, 3.5 parts premix, 0.29 parts lysine, 0.13 parts threonine, 0.03 parts methionine, 0.05 parts tryptophan, and 0.15 parts valine.

[0023] Furthermore, the preservative includes clotrimazole.

[0024] Furthermore, the enzyme preparation includes thermostable phytase 10000.

[0025] Furthermore, the nutritional composition of the premix is ​​as follows: Vitamin A ≥ 120 KIU / kg, Vitamin D3 ≥ 45 KIU / kg, Vitamin E ≥ 3400 mg / kg, Vitamin K3 ≥ 84 mg / kg, Vitamin B1 ≥ 48 mg / kg, Vitamin B2 ≥ 120 mg / kg, Vitamin B6 ≥ 85 mg / kg, Nicotinamide ≥ 600 mg / kg, Pantothenic Acid ≥ 300 mg / kg, Iron ≥ 2800 mg / kg, Copper ≥ 220 mg / kg, Zinc ≥ 1500 mg / kg, Manganese ≥ 2300 mg / kg, and Selenium ≥ 8 mg / kg.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1. To conduct research on the feeding methods of Yuzhong Black Pigs during the fattening period, this invention provides a feeding method for Yuzhong Black Pigs during the fattening period. This invention establishes a precise protein requirement model by constructing fitting curves for the daily weight gain and feed conversion ratio of Yuzhong Black Pigs in the later fattening stage, determining the optimal protein addition range during the fattening period (75kg~100kg), and formulating an optimal low-protein diet formula that meets the growth needs of Yuzhong Black Pigs. This provides a feeding method for Yuzhong Black Pigs during the fattening period (75kg~100kg). This method, based on the breed characteristics of Yuzhong Black Pigs (body size traits, carcass traits, and meat quality in the later fattening stage) and a precise growth model (precise protein requirement model), significantly reduces the crude protein level of the diet (compared to NRC standards or conventional empirical formulas) while precisely meeting the protein requirements of its specific growth stage. This effectively solves the problem of inaccurate protein addition caused by the reliance on general models or empirical formulas in traditional methods. While maintaining or even improving the growth performance (daily weight gain) and feed conversion efficiency (feed to weight ratio) of Yuzhong black pigs, it significantly reduces the amount of expensive protein raw materials (soybean meal) in the feed, significantly reduces feed costs, and reduces nitrogen emissions, thus alleviating environmental pollution pressure.

[0027] 2. To address issues such as "unmet needs of local breeds and low efficiency," a feeding method for Yuzhong Black Pigs during the fattening period (75kg~100kg) is provided. This method overcomes the shortcomings of existing general feeding standards or diets formulated based on other pig breed models that are not specifically tailored to Yuzhong Black Pigs by precisely matching the unique nutritional needs (especially protein requirements) of this local breed in the later stages of fattening. Applying this feeding method can more fully tap the growth potential of Yuzhong Black Pigs, achieving better daily weight gain and a lower feed conversion ratio in the later stages of fattening (75kg~100kg), thereby significantly improving the fattening efficiency and economic benefits of Yuzhong Black Pig farming.

[0028] 3. To address issues such as low protein utilization efficiency and poor cost-effectiveness, a feeding method for Yuzhong Black Pigs in the fattening stage (75kg~100kg) is provided. This method significantly improves the utilization efficiency of protein in the diet by scientifically determining the optimal protein addition range and optimizing the low-protein diet formula. Compared with traditional high-protein diets, while ensuring the ideal growth rate (daily weight gain) of Yuzhong Black Pigs in the later fattening stage, this feeding method can effectively reduce feed consumption per unit weight gain (feed weight ratio) and protein consumption, and significantly improve the economic value of slaughter (thinner backfat, increased eye muscle area, and improved meat quality), thereby optimizing the input-output ratio of the breeding process and improving overall economic benefits.

[0029] In summary, the feeding method provided by this invention is based on a precisely constructed growth model of the Henan Black Pig, scientifically determining the optimal protein supplementation range in the later stages of fattening, and formulating a high-efficiency, low-protein diet accordingly. Compared to traditional feeding methods that rely on general models or empirical formulas, the feeding method provided by this invention has the following advantages:

[0030] (1) Significantly reduce feed costs: By precisely meeting the demand, the crude protein level of the diet is controlled near the lower limit of the optimal range, which greatly reduces the amount of high-priced protein raw materials such as soybean meal.

[0031] (2) Effectively improve breeding efficiency: While reducing protein levels, the optimal amino acid balance ensures the ideal daily weight gain of Yu Nong Black Pigs at this stage and effectively improves feed conversion efficiency (reducing feed conversion ratio).

[0032] (3) Significantly reduced environmental pollution: The invention significantly reduced the crude protein content of the diet and improved protein utilization, thereby greatly reducing nitrogen excretion in fattening pigs and alleviating the environmental pressure faced by the livestock industry. This invention provides scientific and reliable technical support for large-scale, environmentally friendly and efficient breeding of Henan black pigs. Attached Figure Description

[0033] Figure 1 This is the breeding process of Henan black pigs in this invention.

[0034] Figure 2 This is a fitted curve showing the effect of different feed protein levels on the daily weight gain of Yu Nong Black Pigs during the fattening period in this invention.

[0035] Figure 3 This is a fitted curve showing the effect of different feed protein levels on the feed-to-weight ratio of Yu Nong Black Pigs during the fattening period, as described in this invention. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings, but this should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following embodiments are commercially available unless otherwise specified.

[0037] The Yu Nong Black Pigs used in the following examples were sourced from the Yu Nong Black Pig Breeding Farm of Henan Yifa Animal Husbandry Co., Ltd. For details, please refer to the article "Xue Yahui. Genome-wide association analysis and genome matching strategy study of growth traits in Yu Nong Black Pigs [D]. Henan Agricultural University, 2021. DOI:10.27117 / d.cnki.ghenu.2021.000752."

[0038] Among them, the Yuzhong Black Pig is a new local breed developed through three stages: crossbreeding multiple superior local black pig breeds (maternal line) with Duroc (paternal line), followed by selection of breeding materials, crossbreeding for seed production, and generational selection. The breeding process of the Yuzhong Black Pig... Figure 1 As shown.

[0039] Example 1: A feeding method for Yuzhong Black Pigs during the fattening period I. Based on the weight of Yu Nong Black Pigs, the fattening period was divided into three stages: early fattening stage (25kg~50kg), mid-fattening stage (50kg~75kg), and late fattening stage (75kg~100kg). Dietary formulas with different gradient protein levels were established. The different protein levels in these formulas were selected from different values ​​within the range of 10% to 14%. Specifically, the values ​​were 10%, 11%, 12%, 13%, and 14%, respectively. Details are as follows:

[0040] One hundred fattening Yuzhong Black Pigs (75kg-80kg) of uniform health were selected as experimental pigs and randomly divided into 5 groups, with 4 replicates per group and 5 pigs per replicate. Groups 1 to 5 were fed diets with protein content (w / w) of 10.4%, 11%, 12%, 13%, and 14.8%, respectively. Group 5 was the control group, and the other groups were the experimental groups.

[0041] The five groups were designated as CP13, CP12, CP11, CP10, and a control group, respectively. The trial period included a 5-day pre-feeding period and a 40-day regular feeding period.

[0042] The diets were designed according to the NRC (2012) standard, with protein levels set at 10% (CP10 group), 11% (CP11 group), 12% (CP12 group), 13% (CP13 group), and 14% (control group), respectively, based on the w / w protein ratio in the feed. Furthermore, the energy, amino acid, trace element, and vitamin levels in the diets of the above five groups were kept consistent.

[0043] All experimental pigs were managed according to the fattening pig procedures at a farm, including daily disinfection of the pigpens and environmental management. Under the same feeding and management conditions, the experimental and control groups were fed complete pelleted feed with different protein ratios (experimental diets, Table 1), twice a day, at 8:30 and 15:00 respectively. The amount of complete pelleted feed was adjusted according to the daily feed intake of the experimental pigs, and they had free access to water. Throughout the experiment, the pigpens were cleaned regularly to ensure that the experimental pigs maintained a good rearing environment.

[0044] Table 1 Experimental Diet Formulations Note: " / " indicates that it has not been added.

[0045] Table 2. Nutritional levels of the experimental diets (air-dried basal level) II. Dietary formulations with different gradient protein levels were established and fed to multiple late-stage fattening Yuzhong Black Pigs to obtain daily weight gain and feed conversion ratio parameters. Based on the daily weight gain and feed conversion ratio parameters corresponding to the dietary formulations with different gradient protein levels, a precise protein requirement model was fitted. Then, based on the precise protein requirement model, the protein level corresponding to the optimal daily weight gain and feed conversion ratio parameters for late-stage fattening Yuzhong Black Pigs was selected, and the preliminary protein requirement for late-stage fattening Yuzhong Black Pigs was obtained. The precise protein requirement model includes the fitted curves of daily weight gain and feed conversion ratio for late-stage fattening Yuzhong Black Pigs. Details are as follows:

[0046] (1) At the beginning and end of the experiment, the experimental pigs were weighed after fasting for 12 hours. The daily feed intake of the experimental pigs during the experiment was also recorded. The relevant indicators for daily weight gain and feed conversion ratio were calculated using the following formulas.

[0047] The specific calculation formula is as follows: Average Daily Gain (ADG): Reflects the average daily weight gain of experimental pigs. The calculation formula is: ADG = (weight of experimental pigs after the experiment - weight of experimental pigs before the experiment) / experiment time; In the above formula, the unit of ADG is g / d; Average daily feed intake (ADFI): Reflects the average amount of feed consumed per pig per day. ADFI = Feed intake during each repeated trial period / (Trial time × Number of pigs per group). In the above formula, the unit of ADFI is g / (d·head); Feed conversion ratio (F / G): This represents the amount of feed consumed by pigs for each unit of weight gain. F / G = Total feed consumption during the trial period / Total weight gain during the trial period.

[0048] (2) The results of the daily weight gain and feed conversion ratio corresponding to different protein levels were obtained by calculating the above formula, as shown in Table 3.

[0049] Table 3. Effects of protein levels in different experimental diets on the growth performance of Yuzhong Black Pigs during the fattening period. As shown in Table 3, the 13% protein group had the highest daily weight gain, at 0.62 kg / d, which was significantly higher than the control group. P <0.05); the 11% protein group had the lowest feed conversion ratio at 3.32, significantly lower than the control group ( P <0.05. There was no significant difference in feed intake among the groups ( P>0.05).

[0050] (3) Based on the precise protein requirement model, the protein levels corresponding to the optimal daily weight gain and feed conversion ratio parameters of Yu Nong Black Pigs in the later stage of fattening were selected, and the preliminary protein requirements of Yu Nong Black Pigs in the later stage of fattening were obtained as follows: Figure 2 The fitted curves for the effect of protein levels in different feeds (experimental diets) on the daily weight gain of Yuzhong Black Pigs during the fattening period are shown. The fitting result is: y = -0.0208x 2 +0.5072x-2.4418 (R²=0.9963); where y is the daily weight gain and x is the protein level. The curve shows that the highest daily weight gain of Yu Nong Black Pigs during the fattening period was 0.65 kg / d when the feed protein concentration was 12.2%.

[0051] Figure 3 The fitted curve for the effect of different feed protein levels on the feed conversion ratio of Yuzhong Black Pigs during the fattening period is shown. The fitting result is: y = 0.1208x 2 -2.8843x + 20.681 (R² = 0.8589); where y is the daily weight gain and x is the protein level. The curve shows that when the feed protein concentration is 11.94%, the feed conversion ratio for Yu Nong Black Pigs during the fattening period is the lowest, at 3.46.

[0052] As shown above, the initial protein requirement of the selected late-stage fattening Henan black pigs is 11.94%~12.2%.

[0053] The initial protein requirement of 11.94% for Yu Nong Black Pigs in the later stage of fattening was determined by selecting the protein level corresponding to the optimal daily weight gain parameter based on the fitted curve of the daily weight gain of Yu Nong Black Pigs in the later stage of fattening. The initial protein requirement of 12.2% for Yu Nong Black Pigs in the later stage of fattening was determined by selecting the protein level corresponding to the optimal feed conversion ratio parameter based on the fitted curve of the feed conversion ratio of Yu Nong Black Pigs in the later stage of fattening.

[0054] III. Dietary formulations with different gradient protein levels were established and fed to multiple late-finishing Yuzhong Black Pigs to obtain parameters for different traits, including body size, carcass characteristics, and meat quality. The effects of dietary formulations with different gradient protein levels on body size, carcass characteristics, and meat quality of late-finishing Yuzhong Black Pigs were evaluated. The protein levels in the corresponding dietary formulations under the optimal parameters (conditions) for body size, carcass characteristics, and meat quality were selected, as detailed below:

[0055] 1) The effects of different protein level dietary formulations on body size, carcass traits, and meat quality indicators of Yuzhong Black Pigs in the late fattening stage were tested. The specific methods are as follows:

[0056] (1) Digestion and metabolism test Seven days before the end of the experiment, three healthy pigs of near-average weight were randomly selected from each group and housed individually in metabolic cages for the metabolic experiment. Feed intake and defecation / urination patterns were observed. Feces and urine were collected for five days using the total fecal and urine collection method, and daily feed intake, fecal volume, and urine volume were calculated. The diets for the digestive and metabolic experiment corresponded to and were completely identical to those for each group in the feeding experiment.

[0057] Sample Collection: During the digestion and metabolism experiment, the feed intake and uneaten feed volume of each replicate pig were recorded. Feces and urine from all pigs were collected three times daily: 8:00 AM, 12:00 PM, and 5:00 PM. The total weight of feces and the total volume of urine were accurately recorded daily. After mixing, one-quarter of the total feces and urine were sampled. For each replicate, 100g of the mixed feces sample and 100mL of the urine sample were taken, and 10mL of 10% sulfuric acid (by volume) was added to each sample for nitrogen fixation. This was used to determine the crude protein content in fresh feces and urine. The remaining feces samples were weighed and recorded, then dried in a 65℃ constant-temperature drying oven to constant weight. After rehydration at room temperature for 24 hours, the samples were weighed again to calculate the initial moisture content. The air-dried feces samples were pulverized and passed through a 40-mesh sieve for storage. Similarly, feed samples were collected at each stage. The feed and digestion and metabolism samples were stored in a desiccator, and the contents of dry matter, crude protein, crude fat, and crude ash in the samples were uniformly determined.

[0058] (2) Measurement of body size characteristics Body length measurements of experimental pigs should be taken while they are standing naturally. The method involves starting at the atlanto-occipital joint (where the neck and head meet) and measuring along the backline with a soft measuring tape close to the pig's body to the tail root. For back and loin length measurements, precise skeletal landmarks must be located, typically starting at the top of the spinous process of the first thoracic vertebra (roughly above the front edge of the scapula) and ending at the top of the spinous process of the last lumbar vertebra. The measurement line must be straight and accurately positioned to reflect the actual length of the pig's back and loin. The cannula circumference is measured on the left forelimb. The narrowest point above the carpal joint must be located. A soft measuring tape is then used to measure the circumference horizontally around the limb. Care must be taken to ensure the tape is neither too loose nor too tight, as this will affect the accuracy of the data. The measurement of backfat thickness and eye muscle depth needs to be completed using a B-ultrasound instrument: the measurement point for backfat thickness is selected between the fourth rib from the bottom, 5cm away from the back midline. During the operation, the probe needs to be closely attached to the pig's body surface to read the thickness of the subcutaneous fat layer; the eye muscle depth is measured vertically at the position of the longissimus dorsi muscle, 6cm away from the back midline, in the same rib area. The entire process must ensure accurate instrument positioning and standardized operation.

[0059] (3) Determination of carcass traits After the feeding trial ended and the pigs fasted for 12 hours, their fasting weight was measured. Slaughter measurements and sampling were conducted according to the "Technical Regulations for Performance Testing of Lean-Type Breeding Pigs" (GB846-87). After slaughter, carcass weight, dressing percentage, muscle weight, fat weight, bone weight, eye muscle area (area at the 10th rib), backfat thickness (average of backfat thickness at the 1st rib, 6th rib, and last lumbar vertebra), carcass oblique length, and carcass straight length were measured. After cutting, the weights of lean meat, fat, skin, and bone were measured separately, and the lean meat percentage, fat percentage, skin percentage, and bone percentage were calculated.

[0060] (4) Slaughter test Slaughter and sample collection were conducted at the slaughterhouse. Six pigs of similar size were selected for each group. Before slaughter, all 30 Yuzhong Black Pigs were fasted for 24 hours and deprived of water for 8 hours according to sampling requirements. Following anatomical methods, organs such as the heart, liver, spleen, lungs, and kidneys were dissected. Membranes, connective tissue, and surrounding fat were removed from the organs. Residual blood was washed off, and the organs were dried with filter paper and weighed using an electronic scale. Slaughter rate and corresponding organ indices were calculated. Sample collection was conducted within 60 minutes after slaughter. Samples from each slaughtered Yuzhong Black Pig carcass were placed in clean sampling bags and stored in a refrigerated container. All samples were sent for testing after collection.

[0061] (5) Meat quality determination The methods for determining drip loss, acidity (pH 45 min, pH 24 h), and meat color are as specified in the "Technical Specifications for Determination of Pig Muscle Quality".

[0062] Drip loss: Trim and weigh the sample (W1), then tie one end of the meat sample with a thin wire and place it in a safety bag, keeping the sample suspended and not in contact with the bag wall. After sealing the bag, suspend it in a 4℃ incubator for 24 hours. After removing the meat sample, wipe off the liquid on the surface of the meat sample with filter paper and weigh it (W2). Calculate the drip loss according to the formula shown below: Drip loss = [(W1W2) / W1] × 100%; In the above formula, the unit for water loss is %.

[0063] pH value: Insert the pH electrode directly into the middle puncture hole of the longissimus dorsi muscle sample to a depth of not less than 1 cm, completely burying the electrode tip in the meat sample. After the value stabilizes, read the pH value at 45 min (accurate to 0.01). After storing the meat sample in a 4℃ refrigerator for 24 h, measure the pH value at 24 h.

[0064] Flesh color: The color of the eye muscles was measured using a whiteness colorimeter, and the L, a, and b values ​​were read. The L value represents brightness, ranging from 0 to 100, with a higher value indicating greater brightness; the a value represents redness, and the b value represents yellowness. The differences in flesh color were determined based on the measured L, a, and b values.

[0065] 45min L1, a1, b1: represent the brightness, redness, and yellowness of the meat at 45 minutes, respectively.

[0066] 24H L1, a1, b1: These represent the brightness, redness, and yellowness values ​​after 24 hours, respectively.

[0067] The results of the above experiment are as follows: 2) The results of testing different protein level diet formulations on body size traits, carcass traits, and meat quality indicators of Yuzhong Black Pigs in the late fattening stage are as follows: (1) Effects of different feed protein levels on the nutrient digestibility of Henan black pigs As shown in Table 4, with 12% feed protein in water, the protein feed digestibility of Yu Nong Black Pig is the highest, at 67.14%. Table 4. Effects of protein levels in different experimental diets on nutrient digestibility of Yuzhong black pigs during the fattening period. (2) Effects of different dietary protein levels on body size traits Table 5 shows the effects of different feed protein levels on body size traits of Yuzhong Black Pigs during the fattening period. Specifically, when the feed protein level was 10.4% and 11%, the back and loin length of Yuzhong Black Pigs during the fattening period was significantly lower than that of the control group. P <0.05); When the feed protein level was 11%, the backfat thickness of the Yuzhong Black Pigs during the fattening period was the lowest, significantly lower than that of the other groups ( P <0.05).

[0068] Table 5. Effects of different dietary protein levels on body size traits of Yuzhong Black Pigs during the fattening period. (3) Effects on carcass traits Table 6 shows the effects of different feed protein levels on carcass traits of Yuzhong Black Pigs during the fattening period. Specifically, when the feed protein level was 11%, the carcass backfat thickness and fat percentage of Yuzhong Black Pigs during the fattening period were the lowest, significantly lower than the other groups. Furthermore, the eye muscle area of ​​Yuzhong Black Pigs with a protein level of 11% was significantly higher than that of the other groups.

[0069] Table 6. Effects of different dietary protein levels on carcass traits of Yuzhong Black Pigs during the fattening period. (4) Effects of different feed protein levels on meat quality Table 7 shows the effects of different feed protein levels on the quality of Yu Nong black pork during the fattening period.

[0070] Drip loss: Drip loss fluctuated between 1.25% and 2.65% under different feed protein levels, with no significant differences between levels. P =0.406). 45-minute pH: values ​​ranged from 6.25 to 6.47, with no significant differences among protein levels. P =0.551). 24h pH: There were significant differences in pH values ​​over 24 hours under different dietary protein levels ( P <0.05). Among them, the pH value was 5.32±0.11 when the feed protein content was 14.8%, significantly lower than other groups. There were no significant differences in L1, a1, and b1 values ​​among different protein levels at 45 min. There were also no significant differences in L1, a1, and b1 values ​​among different protein levels at 24 h, indicating that the feed protein level had little effect on the color parameters of pork after 24 hours. However, numerically, the L1 value tended to decrease gradually with decreasing protein levels, the a1 value was lowest at a protein content of 11%, and the b1 value fluctuated less.

[0071] Overall, feed protein levels have a certain impact on the meat quality of Yu Nong Black Pigs during the fattening period, with a significant impact on 24-hour pH value and a smaller impact on drip loss and colorimeter parameters.

[0072] Table 7. Effects of different feed protein levels on the quality of Yuzhong black pork during the fattening period. 3) The optimal protein level in the diet for body size, carcass traits, and meat quality was 11%. Specifically, 1) the protein level in the diet corresponding to the lowest backfat thickness (17.30mm±4.83mm) and deepest eye muscle depth (44.84mm±8.15mm) among the body size traits of the Yuzhong Black Pig was selected, resulting in a protein level of 11%. (The backfat thickness measured at 11% protein level was significantly lower than other protein level groups by 18.6%~23.7%, while the eye muscle depth was excellent, significantly better than the high-protein group (14.76% at 40.78mm) and the low-protein group (10.4% at 40.83mm)). 2) Among the carcass traits, the highest lean meat percentage (60.69%±8.98%) and largest eye muscle area (3949.52mm) were selected for the Yuzhong Black Pig. 2 ±616.80mm 2 The protein level in the diet under the specified parameters (conditions) was determined to be 11% (the lean meat percentage measured at the 11% protein level was significantly higher than the 50.63% in the 13% group). P≤0.05), which is 2.14% higher than the second-best group (10.4% of 58.55%); at the same time, the eye muscle area is the largest, significantly higher than all other groups by 39%~41%, P≤0.05). 3) Select the protein level in the diet corresponding to the parameter (condition) with the highest 24-hour pH value (the core indicator of meat preservation) and the lowest meat shear force (the best meat tenderness) in meat quality. The protein level in the diet was found to be 11% (the 24-hour pH value of meat measured at the 11% protein level was 5.56±0.11, significantly higher than the 5.31 of the 14.76% group). P ≤0.05 (pH>5.4 effectively inhibits dripping water loss), indicating better water retention at this level; simultaneously, at the 11% protein level, the meat exhibited the lowest shear force, 44.02±3.74 N, which was 25.6%~34.3% lower than all other groups. P ≤0.05 indicates that the meat has the best tenderness at this level.

[0073] IV. Based on the preliminary protein requirements of Yuzhong Black Pigs in the late fattening stage, and combined with the protein levels in the corresponding diet formulas under the optimal body size, carcass, and meat quality parameters (conditions), the precise protein requirements of Yuzhong Black Pigs in the late fattening stage are determined as follows: The results above show that the optimal protein requirement for Yu Nong Black Pigs during the fattening stage is 11%–12%, a significantly lower percentage than other imported pig breeds. At this protein intake level, Yu Nong Black Pigs outperform the control group in daily weight gain, feed conversion ratio, and backfat thickness. Therefore, it is recommended that the protein content of the diet for Yu Nong Black Pigs during the fattening period be set at approximately 12%. At this level, all performance indicators of Yu Nong Black Pigs are superior to those of diets with a traditional 14.8% protein level. Adopting this protein level can effectively reduce costs and improve efficiency. Specifically, the precise protein requirement for Yu Nong Black Pigs after fattening is 11%–12%. This is determined by combining the initial protein requirement of Yu Nong Black Pigs in the later fattening stage with the protein levels in the corresponding diets under optimal body size, carcass traits, and meat quality parameters (conditions), taking the intersection of these values, and dividing the decimal point to obtain a single integer value.

[0074] 5. Based on the precise protein requirements of the Yu Nong Black Pigs in the later stages of fattening, determine the diet formula, prepare the diet, and feed them.

[0075] The obtained diet formula was based on the precise protein requirements of Yuzhong Black Pigs in the late fattening stage. The diet, by weight, is made from the following ingredients: 70.1 parts corn, 5.2 parts high-fat DDGS, 3.35 parts soybean meal, 17.08 parts wheat bran, 0.05 parts ethoxyquin, 0.05 parts preservative, 0.02 parts enzyme preparation, 3.5 parts premix, 0.29 parts lysine, 0.13 parts threonine, 0.03 parts methionine, 0.05 parts tryptophan, and 0.15 parts valine.

[0076] The preservatives include clotrimazole.

[0077] The enzyme preparation includes thermostable phytase 10000.

[0078] The nutritional composition of the premix is ​​as follows: Vitamin A 120 KIU / kg, Vitamin D3 45 KIU / kg, Vitamin E 3400 mg / kg, Vitamin K3 84 mg / kg, Vitamin B1 48 mg / kg, Vitamin B2 120 mg / kg, Vitamin B6 85 mg / kg, Nicotinamide 600 mg / kg, Pantothenic Acid 300 mg / kg, Iron 2800 mg / kg, Copper 220 mg / kg, Zinc 1500 mg / kg, Manganese 2300 mg / kg, and Selenium 8 mg / kg.

[0079] Therefore, the feeding method for Yuzhong black pigs during the fattening period provided by this invention has the following important value: 1. Disruptive restructuring of protein demand This invention is the first to clearly define the optimal protein level for the fattening period of Henan black pigs as 11%-12%, which is more than 20% lower than the traditional diet (14.8%). This breaks through the high-protein feeding paradigm of foreign pig breeds and fills the gap in precision nutrition for local pig breeds.

[0080] 2. Excellent growth performance and feed efficiency Daily weight gain increased by 18%: the 12% protein group achieved a daily weight gain of 0.59 kg / day (vs. 0.50 kg / day in the control group). P <0.05) Feed conversion ratio decreased by 18.6%: the feed conversion ratio of the 11% protein group was 3.32 (compared to 4.41 in the control group). P <0.05), saving 1.09 kg of feed for every 1 kg of weight gain.

[0081] 3. Revolutionary improvement in carcass quality Backfat thickness decreased sharply: the 11% group had the lowest live backfat thickness (17.31 mm) and carcass backfat thickness (23.11 mm) across the entire event, a reduction of 17%~31% compared to the control group. P <0.05).

[0082] Excellent muscle development: The ocular muscle area of ​​the 11% group increased by 39.7% (3949.52 mm² vs. 2826.54 mm² in the control group). P <0.05).

[0083] The fat percentage decreased by 31.7%: the fat percentage in the 11% group was only 16.74% (vs. 24.50% in the control group). P <0.05).

[0084] The results of this invention in terms of growth performance, feed cost, and carcass production revenue are shown in Table 8.

[0085] Table 8. Comparison of the benefit improvement of this invention compared to the control group (14.76%) Note: Based on a fattening period weight gain of 80 kg / head and a soybean meal price of ¥3200 / ton, the feed cost per ton is reduced by ¥80-120. "-" indicates not included in the statistics. "↓" indicates a decrease, and "↑" indicates an increase.

[0086] It can be seen that the feeding method for the fattening period of Yu Nong Black Pig provided by this invention has achieved a quadruple breakthrough in accelerating growth, reducing feed consumption, upgrading carcasses, and reducing costs by precisely controlling the dietary protein level at 12%. It is the first time that a low-carbon and high-efficiency fattening technology system adapted to the new breed - Yu Nong Black Pig has been established.

[0087] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

[0088] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A feeding method for Yuzhong Black Pigs during the fattening period, characterized in that, Includes the following steps: Based on the weight of the Yu Nong Black Pig, the fattening period of the Yu Nong Black Pig is divided into three stages: early fattening stage: 25kg~50kg, middle fattening stage: 50kg~75kg, and late fattening stage: 75kg~100kg. Dietary formulations with different gradient protein levels were set up and fed to multiple late-stage fattening Yu Nong Black Pigs to obtain parameters such as daily weight gain, feed conversion ratio, and different traits; among which, different traits included body size traits, carcass traits, and meat quality. Based on the parameters of daily weight gain, feed conversion ratio, and protein level corresponding to diet formulations with different protein gradients, a precise protein requirement model is fitted. Then, based on the precise protein requirement model, the protein level corresponding to the optimal daily weight gain and feed conversion ratio parameters for Yuzhong black pigs in the late fattening stage is selected, and the preliminary protein requirement for Yuzhong black pigs in the late fattening stage is obtained. The precise protein requirement model includes the fitted curve of daily weight gain and the fitted curve of feed conversion ratio for Yuzhong black pigs in the late fattening stage. Select the protein level in the diet formulation corresponding to the parameters of optimal body size, carcass traits, and meat quality; Based on the preliminary protein requirements of Yu Nong Black Pigs in the later stages of fattening, and combined with the protein levels in the diet formula corresponding to the parameters of optimal body size, carcass traits, and meat quality, the precise protein requirements of Yu Nong Black Pigs in the later stages of fattening are determined. Based on the precise protein requirements of the Yu Nong Black Pigs in the later stages of fattening, the diet formula was determined, the diet was prepared, and the pigs were fed.

2. The feeding method according to claim 1, characterized in that, The fitting curve for the daily weight gain of Yuzhong Black Pigs in the later fattening stage is: y = -0.0208x 2 +0.5072x-2.4418, where y is the daily weight gain and x is the protein level; the fitted curve of the feed conversion ratio of Yu Nong Black Pigs in the later stage of fattening is: y=0.1208x 2 -2.8843x+20.681, where y is the daily weight gain and x is the protein level.

3. The feeding method according to claim 1, characterized in that, The initial protein requirement for Yuzhong black pigs in the later fattening stage is 11.94%~12.2%; The initial protein requirement of 11.94% for Yu Nong Black Pigs in the later stage of fattening was determined by selecting the protein level corresponding to the optimal daily weight gain parameter based on the fitted curve of the daily weight gain of Yu Nong Black Pigs in the later stage of fattening. The initial protein requirement of 12.2% for Yu Nong Black Pigs in the later stage of fattening was determined by selecting the protein level corresponding to the optimal feed conversion ratio parameter based on the fitted curve of the feed conversion ratio of Yu Nong Black Pigs in the later stage of fattening.

4. The feeding method according to claim 1, characterized in that, The optimal body size, carcass characteristics, and meat quality parameters correspond to a protein level of 11% in the diet.

5. The feeding method according to claim 1, characterized in that, Different gradient protein levels in dietary formulations refer to different values ​​selected within the range of 10% to 14%.

6. The feeding method according to claim 1, characterized in that, The precise protein requirement of Yu Nong Black Pigs in the later fattening stage is obtained by combining the preliminary protein requirement of Yu Nong Black Pigs in the later fattening stage with the protein level in the diet formula corresponding to the parameters of optimal body size, carcass traits and meat quality, taking the intersection and removing the decimal part of the values, and obtaining a numerical index with only integers.

7. The feeding method according to claim 6, characterized in that, The precise protein requirement for Yu Nong Black Pigs in the later stages of fattening is 11%-12%.

8. The feeding method according to claim 7, characterized in that, The diet formula is obtained based on the precise protein requirements of the Yu Nong Black Pigs in the later stages of fattening. The diet, by weight, is made from the following ingredients: 70.1 to 72.4 parts corn, 2.685 to 5.2 parts high-fat DDGS, 3.35 to 7 parts soybean meal, 15.38 to 17.08 parts wheat bran, 0.05 parts ethoxyquinoline, 0.05 parts preservative, 0.02 parts enzyme preparation, 3.5 parts premix, 0.29 to 0.355 parts lysine, 0.13 to 0.17 parts threonine, 0.03 to 0.05 parts methionine, 0.05 to 0.055 parts tryptophan, and 0.15 to 0.19 parts valine.

9. The feeding method according to claim 8, characterized in that, The diet, by weight, is made from the following ingredients: 70.1 parts corn, 5.2 parts high-fat DDGS, 3.35 parts soybean meal, 17.08 parts wheat bran, 0.05 parts ethoxyquinoline, 0.05 parts preservative, 0.02 parts enzyme preparation, 3.5 parts premix, 0.29 parts lysine, 0.13 parts threonine, 0.03 parts methionine, 0.05 parts tryptophan, and 0.15 parts valine.

10. The feeding method according to claim 9, characterized in that, The preservative includes clotrimazole; The enzyme preparation includes thermostable phytase 10000; The nutritional composition of the premix is ​​as follows: Vitamin A ≥ 120 KIU / kg, Vitamin D3 ≥ 45 KIU / kg, Vitamin E ≥ 3400 mg / kg, Vitamin K3 ≥ 84 mg / kg, Vitamin B1 ≥ 48 mg / kg, Vitamin B2 ≥ 120 mg / kg, Vitamin B6 ≥ 85 mg / kg, Nicotinamide ≥ 600 mg / kg, Pantothenic Acid ≥ 300 mg / kg, Iron ≥ 2800 mg / kg, Copper ≥ 220 mg / kg, Zinc ≥ 1500 mg / kg, Manganese ≥ 2300 mg / kg, and Selenium ≥ 8 mg / kg.

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