Application of L-malic acid in simultaneously improving growth performance and muscle quality of Hunan village black pigs in fattening period

Abstract

The invention discloses application of L-malic acid in simultaneously improving growth performance and muscle quality of Hunan village black pigs in a fattening period. The addition amount of the L-malic acid is 0.5% of the weight of feed for the Hunan village black pigs in the fattening period.

Description

Technical Field

[0001] The present invention belongs to the technical field of animal nutrition, and particularly relates to the application of L - malic acid in simultaneously improving the growth performance and muscle quality of Xiangcun black pigs during the fattening period. Background Art

[0002] Existing research on adding L - malic acid to the diet mostly focuses on the weaned piglet stage, and its main functions are to regulate the intestinal flora, promote the absorption of nutrients and improve the growth performance. For example, adding 1% of L - malic acid to the diet of weaned piglets significantly reduces the intestinal inflammatory level, increases the villus height of the jejunum, and improves intestinal health. Adding 0.2% of L - malic acid to the diet of weaned piglets can significantly improve the survival rate and daily weight gain of piglets. There are also research reports that adding a mixture of L - malic acid to the diet of weaned piglets can improve the pork quality by regulating the transformation of skeletal muscle fiber types and increasing the proportion of oxidative muscle fibers. However, the diet compositions in the piglet stage and the fattening stage are significantly different. Whether the effect of regulating meat quality in the piglet stage can continue after the fattening stage is unknown. Therefore, it is necessary to consider regulating meat quality in the fattening stage. However, whether adding L - malic acid to the diet of fattening pigs can improve meat quality has not been reported, and whether it can have a positive impact on growth performance while improving meat quality has not been reported either. There is also no report on using L - malic acid to regulate the growth performance and pork quality of local pig breeds. Summary of the Invention

[0003] The present invention aims to overcome the deficiencies of the prior art and provides the application of L - malic acid in simultaneously improving the growth performance and muscle quality of Xiangcun black pigs during the fattening period.

[0004] To achieve the above object, the technical solution provided by the present invention is as follows:

[0005] Adding L - malic acid equivalent to 0.5% of the weight of the diet for Xiangcun black pigs during the fattening period to the diet for Xiangcun black pigs during the fattening period can simultaneously improve the growth performance and muscle quality of Xiangcun black pigs during the fattening period. The diet for Xiangcun black pigs during the fattening period consists of a basal diet plus L - malic acid.

[0006] Preferably, the improvement of the growth performance of Xiangcun black pigs during the fattening period is achieved by increasing the daily weight gain and reducing the feed - to - gain ratio to improve the growth performance of Xiangcun black pigs during the fattening period; the improvement of the muscle quality of Xiangcun black pigs during the fattening period is achieved by simultaneously increasing the intramuscular fat content, changing the composition of muscle free amino acids, increasing the content of flavor nucleotides and regulating the muscle fiber type to improve the muscle quality of Xiangcun black pigs during the fattening period.

[0007] Preferably, the fattening period is 120 to 180 days of age.

[0008] Preferably, the purity of the L - malic acid > 99%.

[0009] The present invention will be further described below:

[0010] Xiangcun black pigs are new livestock and poultry breeds approved through national variety certification. The female parent is the local Hunan breed, Taoyuan black pig, and the male parent is the lean-type Duroc pig. They have good growth performance, high feed conversion rate, and excellent meat quality.

[0011] L-malic acid is added to the diet of Xiangcun black pigs at an addition amount of 0.5%, that is, 5 kg / t. The purity of L-malic acid is greater than 99%, and the addition stage is from 120 to 180 days of age. The test results show that L-malic acid can regulate muscle metabolism and fat deposition through its metabolic regulation function, thereby improving the growth performance and muscle quality of Xiangcun black pigs (increasing the daily weight gain during the fattening period of Xiangcun black pigs, reducing the feed-to-weight ratio during the fattening period, and improving the growth performance of fattening pigs; and improving the pork quality by increasing the intramuscular fat content, changing the composition of free amino acids in muscle, increasing the content of flavor nucleotides, and regulating the composition of muscle fiber types), providing technical support for improving the production efficiency of live pigs in China and the quality of pork. Description of the Drawings

[0012] Figure 1 Effect of adding 0.5% L-malic acid to the diet on the composition of muscle fiber types in the longissimus dorsi muscle of 180-day-old Xiangcun black pigs; among them, (A) immunofluorescence staining was used to label slow-twitch oxidative and fast-twitch glycolytic muscle fiber types in the longissimus dorsi muscle sections (slow-twitch oxidative muscle fibers, MYH7+; fast-twitch glycolytic muscle fibers, MYH1+), and (B) the percentages of slow-twitch oxidative and fast-twitch glycolytic muscle fibers and the cross-sectional area of muscle fibers were statistically analyzed. Detailed Embodiments

[0013] Example 1:

[0014] Sixteen 120-day-old Xiangcun black pigs with similar body weights (60.01 ± 0.264 kg) were selected for the test and randomly divided into 2 groups, with 8 pigs in each group. They were fed individually in single pens and given a basal diet and a diet supplemented with L-malic acid (5 kg / t, 0.5%) respectively. The composition of the basal diet and the nutritional level are shown in Table 1. The L-malic acid was all purchased from Great Wall Biochemical Engineering Co., Ltd., and the purity of L-malic acid was greater than 99%.

[0015] The test animals were allowed to eat and drink freely. The test period was 60 days. They were slaughtered and sampled at 180 days of age to evaluate the growth performance, meat quality-related indicators, conventional components of muscle tissue, content of free amino acids in the longissimus dorsi muscle, content of flavor nucleotides in the longissimus dorsi muscle, and composition of muscle fiber types in the longissimus dorsi muscle of the test pigs.

[0016] Table 1 Composition of the basal diet and nutritional level of Xiangcun black pigs (%, fed on the basis)

[0017]

[0018] Nutritional components

[0019]

[0020] Note: The premix provides per kilogram of feed: vitamin A, 10800 IU; vitamin D3, 4000 IU; vitamin E, 40 IU; vitamin K3, 4 mg; vitamin B1, 6 mg; vitamin B2, 12 mg; vitamin B6, 6 mg; vitamin B12, 0.05 mg; biotin, 0.2 mg; folic acid, 2 mg; niacin, 50 mg; D-pantothenic acid, 25 mg; copper, 60 mg; iron, 60 mg; manganese, 10 mg; zinc, 40 mg; iodine, 0.1 mg; selenium, 0.2 mg.

[0021] As can be seen from Table 2, compared with the control group, adding 0.5% L-malic acid to the diet significantly increased the average daily gain of Xiangcun black pigs from 120 to 180 days of age (P<0.05), and adding 0.5% L-malic acid to the diet significantly reduced the feed-to-gain ratio at this stage (P<0.05).

[0022] Table 2 Effects of adding 0.5% L-malic acid to the diet on the growth performance of Xiangcun black pigs (n = 8)

[0023]

[0024] As can be seen from Table 3, compared with the control group, adding 0.5% L-malic acid to the diet significantly reduced the yellowness value of the longissimus dorsi muscle at 45 minutes and 24 hours after slaughter of 180-day-old Xiangcun black pigs (P<0.05), and there was a tendency to increase the redness value of the longissimus dorsi muscle at 45 minutes after slaughter (P = 0.057). Adding 0.5% L-malic acid to the diet significantly reduced the cooking loss (P<0.05) and drip loss (P<0.05) of the longissimus dorsi muscle, and significantly increased the marbling score of the longissimus dorsi muscle (P<0.01). Therefore, adding 0.5% L-malic acid to the diet can improve the meat quality of 180-day-old Xiangcun black pigs.

[0025] Table 3 Effects of adding 0.5% L-malic acid to the diet on the meat quality of Xiangcun black pigs (n = 8)

[0026]

[0027]

[0028] As can be seen from Table 4, compared with the control group, adding 0.5% L-malic acid to the diet significantly increased the crude protein content of the longissimus dorsi muscle of 180-day-old Xiangcun black pigs (P<0.05), significantly increased the intramuscular fat content of the longissimus dorsi muscle and soleus muscle (P<0.05), and there was also a tendency to increase the intramuscular fat content in the psoas major muscle (P<0.1).

[0029] Table 4 Effects of 0.5% L - malic acid supplementation in diet on the conventional composition of muscles of Xiangcun black pigs (n = 8)

[0030]

[0031] As can be seen from Table 5, compared with the control group, supplementation of 0.5% L - malic acid in the diet significantly increased the content of essential amino acid histidine in the longissimus dorsi muscle of 180 - day - old Xiangcun black pigs (P < 0.01), and decreased the contents of leucine and methionine (P < 0.01). Supplementation of 0.5% L - malic acid in the diet had a tendency to increase the content of serine in the longissimus dorsi muscle of 180 - day - old Xiangcun black pigs (P < 0.1), and significantly decreased the content of aspartic acid (P < 0.01). Therefore, supplementation of 0.5% L - malic acid in the diet significantly changed the composition of free amino acids in the longissimus dorsi muscle of 180 - day - old Xiangcun black pigs.

[0032] Table 5 Effects of 0.5% L - malic acid supplementation in diet on the content of free amino acids in the longissimus dorsi muscle of Xiangcun black pigs (n = 8)

[0033]

[0034]

[0035] As can be seen from Table 6, compared with the control group, supplementation of 0.5% L - malic acid in the diet significantly increased the content of flavor nucleotide IMP in the longissimus dorsi muscle of 180 - day - old Xiangcun black pigs (P < 0.01), increasing the umami of pork.

[0036] Table 6 Effects of 0.5% L - malic acid supplementation in diet on the content of flavor nucleotides in the longissimus dorsi muscle of Xiangcun black pigs (n = 8)

[0037]

[0038] From Figure 1 it can be seen that, compared with the control group, supplementation of 0.5% L - malic acid in the diet significantly increased the percentage of oxidative muscle fibers (MYH7 + ) in the longissimus dorsi muscle of 180 - day - old Xiangcun black pigs (P < 0.0001), and at the same time significantly decreased the percentage of glycolytic muscle fibers (MYH1 + ) (P < 0.0001). Supplementation of 0.5% L - malic acid in the diet significantly decreased the cross - sectional area of muscle fibers in the longissimus dorsi muscle of 180 - day - old Xiangcun black pigs (P < 0.001).

[0039] In summary, the following conclusions can be drawn: 1. Adding 0.5% L-malic acid to the diet of Xiangcun black pigs aged 120 to 180 days can increase the daily weight gain, reduce the feed-to-meat ratio, and improve the growth performance of Xiangcun black pigs during the fattening period. 2. Adding 0.5% L-malic acid to the diet of Xiangcun black pigs aged 120 to 180 days can improve the meat color, water-holding capacity, and intramuscular fat content of Xiangcun black pigs at 180 days of age, and improve the pork quality. 3. Adding 0.5% L-malic acid to the diet of Xiangcun black pigs aged 120 to 180 days can regulate the composition of free amino acids in the longissimus dorsi muscle of Xiangcun black pigs at 180 days of age and increase the content of flavor nucleotides, improving the flavor of pork. 4. Morphological analysis found that adding 0.5% L-malic acid to the diet of Xiangcun black pigs aged 120 to 180 days can improve the muscle fiber type composition, increase the proportion of slow-twitch oxidative muscle fibers, and reduce the cross-sectional area of muscle fibers.

[0040] Therefore, adding 0.5% L-malic acid to the diet during the fattening period can improve the breeding efficiency of Xiangcun black pigs and simultaneously improve the application effect of pork quality.

Claims

1. Application of L-malic acid in simultaneously improving growth performance and muscle quality of Xiangcun black pigs during the fattening period, characterized in that, The addition amount of the L-malic acid is 0.5% of the weight of the diet for Xiangcun black pigs during the fattening period.

2. Use of L-malic acid in simultaneously improving growth performance and muscle quality of Xiangcun black pigs during the fattening period, characterized in that, The diet for Xiangcun black pigs during the fattening period is a basal diet plus L-malic acid.

3. The application of L-malic acid in simultaneously improving the growth performance and muscle quality of Xiangcun black pigs during the fattening period as described in claim 1, characterized in that, The improvement of the growth performance of Xiangcun black pigs during the fattening period is to increase the daily weight gain while reducing the feed-to-gain ratio; the improvement of the muscle quality of Xiangcun black pigs during the fattening period is to increase the intramuscular fat content, change the composition of free amino acids in the muscle, increase the content of flavor nucleotides and regulate the muscle fiber type at the same time.

4. Use of L-malic acid in simultaneously improving the growth performance and muscle quality of Xiangcun black pigs during the fattening period, characterized in that, The fattening period is 120 to 180 days of age.

5. The application of L-malic acid in simultaneously improving the growth performance and muscle quality of Xiangcun black pigs during the fattening period as claimed in claim 1, characterized in that, The purity of the L-malic acid > 99%.

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