JP7804629B2 - Formula feed that improves back fat thickness in pork pigs - Google Patents

Description

The present invention relates to a compound feed for fattening pork that improves back fat thickness in pork pigs.

Pig farms in Japan are increasingly introducing genetically improved breeding pigs (hereinafter referred to as prolific sows) from overseas. Compared to breeding pigs traditionally raised domestically, prolific sows not only produce a significantly higher number of piglets per farrowing, but also significantly improve the piglets' own weight gain rate. However, piglets from prolific sows have significantly thinner backfat at the time of shipping than traditional domestic pigs. This has created a major problem: a high proportion of pigs are judged to be "thin fat" during carcass grading by the Japan Meat Grading Association, resulting in a lower grade and lower carcass price. If the backfat thickness of piglets from prolific sows can be improved while maintaining their high weight gain performance using compound feed, it would greatly contribute to improving the productivity of pig farmers.

Patent Document 1 describes a pig feed additive containing 50% by weight or more of glycerides with a saturated fatty acid composition of C14-16:0. Adding the additive to a 0.5% by weight compound feed is said to improve body weight gain and feed conversion ratio, and increase backfat thickness. However, this invention is targeted at piglets with thick backfat, with an average backfat thickness of 2.5 cm or more, not thin-fat piglets with a backfat thickness of 1.2 cm or less.

Non-Patent Document 1 found that adding rice and non-standard soybeans to commercially available feed increased backfat thickness, but a decline in weight gain was observed in Test Group 3, where backfat thickness increased compared to the control group fed only commercial feed, and the authors only state that rice and non-standard soybeans can be used without affecting weight gain or meat quality up to the proportions in Test Group 2, where there was no difference in backfat thickness. In Non-Patent Document 2, palm oil was added to the feed at a maximum of 7% by weight, increasing the energy content (total amount of digestible nutrients) in the feed by approximately 10% by weight compared to the control group, and although this resulted in improved weight gain, no increase in backfat thickness was observed.

Japanese Patent Application Laid-Open No. 2005-6584

The effect of feeding feed rice and non-standard soybeans to fattening pigs on growth and meat quality, Hoshikawa et al., Yamagata Prefecture Agricultural Research Report No. 12, pp. 45-52, 2020. The effect of adding palm oil to a mixture of feed rice, barley, and tea processing residues on the feeding performance and meat quality of pigs in the late summer fattening stage, Wakiya et al., Journal of the Japanese Society of Swine Science, Vol. 51, pp. 207-212, 2014.

The objective of the present invention is to solve the problems of the conventional technology described above and to provide a compound feed that can improve back fat thickness, which has high commercial value, while maintaining high weight gain in fattening pigs.

As mentioned above, piglets from prolific sows have significantly thinner backfat thickness at the time of shipping than traditional domestic pigs, and a large proportion of pigs are judged to be "thin fat" during carcass grading by the Japan Meat Grading Association, resulting in a lower grade and a drop in carcass price, which is a major problem. In addition, as Non-Patent Document 1 states, attempts to increase backfat thickness through feed are accompanied by a decline in weight gain, so reduced productivity is also an issue. Furthermore, piglets from prolific sows are slow to respond to feed that increases backfat thickness, and simply increasing the energy content of the feed has not solved the problem of thin fat.

After extensive research, the inventors discovered that by keeping the crude fat content of compound feed for fattening swine low and increasing the energy content through the use of grains, using net energy as an indicator of energy content, and keeping the crude protein content of the feed low while maintaining a constant level of amino acid content through the use of crystalline amino acids, it is possible to increase backfat thickness while maintaining weight gain performance, even in piglets from prolific sows, and reduce the risk of lower grading grades due to thin fat, thereby completing the present invention.

In other words, by not only increasing the energy content of the feed but also decreasing the crude protein content, it became possible to improve pigs' feed intake and dramatically increase their daily energy intake. In this case, by using net energy instead of the conventional total digestible nutrient content as the energy content of the feed, it became possible to more accurately evaluate and control the energy content in the feed and the pigs' daily energy intake. In addition, it was discovered that decreasing the crude protein content of the feed not only contributes to an increase in net energy in the feed, but also has the effect of increasing feed intake.
A decrease in crude protein also leads to a decrease in pig growth performance, but by using crystalline amino acids to maintain a constant level of amino acid content in the feed, it is possible to prevent a decrease in growth performance.Even in piglets from prolific sows, where it was difficult to increase backfat thickness, it was possible to increase backfat thickness while maintaining growth performance, thereby improving quality at the time of shipment.

That is, the embodiments of the present invention are as follows.
[1] A compound feed for fattening pork intended for thin-fat pigs with a back fat thickness of 1.2 cm or less, containing a crude protein content of 11.5% by weight or less, a crude fat content of 3.0% by weight or less, a total digestible nutrient content of 79.0% by weight or more, a net energy content of 2,650 kcal or more per kg of feed, and lysine in the range of 0.60 to 0.90% by weight in the total feed.
[2] A compound feed for fattening pork pigs according to [1], in which the total proportion of grains in the total feed is 80% by weight or more.

The compound feed for fattening swine of the present invention can increase backfat thickness and reduce the percentage of pigs that are judged to be thin-fat at the time of shipping. Although the feed has a low crude protein content, it retains sufficient amino acids, making it possible to maintain previous weight gain figures. As a result, it is possible to improve the grade and price of carcasses without reducing pig productivity, contributing to improved profits for pig farms.

The compound feed for fattening swine of the present invention is a feed containing a total of 80% by weight or more of grains such as corn, polished rice, brown rice, wheat, wheat flour, barley, rye, milo, breadcrumbs, and sweet potato. Other grain ingredients may or may not be included.

The crude protein content of the feed is 11.5% by weight or less, preferably 11.0% by weight or less, more preferably 10.5% by weight or less, even more preferably 10.0% by weight or less, and most preferably 9.5% by weight or less. There are no particular restrictions on the type of protein source, such as vegetable oil cakes, animal feed, or cornstarch, and raw materials commonly used in compound feed for fattening swine may be used. Specific examples include, but are not limited to, soybean oil cake, rapeseed oil cake, corn gluten meal, corn jam meal, fish meal, pork/chicken meal, chicken meal, pig blood meal, and corn distiller's grain solubles.

The lysine content in the feed is 0.60 to 0.90% by weight, preferably 0.65 to 0.80% by weight. If the lysine content exceeds 0.90% by weight, fat deposition will be inhibited and the effects of the present invention will not be obtained. The lysine used here is not particularly limited, and raw materials commonly used in compound feed for fattening swine may be used. When using crystalline lysine, either L-lysine hydrochloride or L-lysine sulfate may be used, as long as it is approved as a feed additive. The lysine in the present invention is a value that includes not only the crystalline lysine in the feed, but also all lysine contained in other raw materials.

The crude fat content in the feed is 3.0% by weight or less, preferably 2.5% by weight or less, more preferably 2% by weight or less, even more preferably 1.5% by weight or less, and most preferably 1.0% by weight or less. Fats and oils may be added, but in order to achieve a grain content of 80% by weight or more and a crude fat content of 3.0% by weight or less, it is desirable to add no fats or oils. Note that the crude fat content in this invention includes not only the fats and oils in the feed but also all fats contained in other ingredients.

The energy content of the feed is 79.0% by weight or more, preferably 80.0% by weight or more, more preferably 81.0% by weight or more, and most preferably 82.0% by weight or more, in terms of the total amount of digestible nutrients. The total amount of digestible nutrients is a value calculated by multiplying the digestible protein, digestible carbohydrate, and digestible crude fat by 2.25 for each raw material used in the feed, and the total amount of digestible nutrients in the feed is this total value.

The energy content of the feed is at least 2,650 kcal net energy per kg of feed, and may be, for example, at least 2,700 kcal, at least 2,750 kcal, or at least 2,800 kcal. Net energy refers to the energy used for body maintenance and growth, remaining after subtracting the energy excreted in feces, urine, and heat production from the total energy contained in the feed ingredients (energy generated when burned). The net energy of each feed ingredient in this invention is based on the value for NE growing pig (kcal) in the INRAE-CIRAD-AFZ Feed tables provided by INRA in France, and the net energy in the feed is the total value.

The breed of pig is not particularly limited, and includes Landrace, Large Yorkshire, Duroc, Middle Yorkshire, Berkshire, and crossbreeds thereof. Particularly preferred examples include pork pigs produced from high-performing sows (prolific sows) recently introduced from overseas.

The feed of the present invention is fed during the fattening period of pork pigs (from when the pigs weigh approximately 70 kg until they are shipped).

The effects of the present invention are demonstrated in the following examples, but the present invention is not limited to these.

Demonstration experiment 1
(1) Test contents The growth and shipping performance of piglets born from prolific sows imported from overseas was confirmed. The feed was a commercially available compound feed for fattening pork, which was given ad libitum. A total of 63 pigs were used in the test, with 12 replicates (4-6 pigs per replicate). The growth performance of piglets ranging in weight from approximately 70 kg to 115 kg and the values on the carcass grading specifications issued at the time of shipping were confirmed.
In addition, even if the back fat thickness is 1.2 cm or more, the carcass grading may be downgraded as it is judged to have a "thin belly," and even if the back fat thickness is 1.2 cm or less, if there is a downgrading factor of "heavy weight," the "thin back" may not be listed in the carcass grading specification, so the number of downgraded heads and the number of head with a back fat thickness of 1.2 cm or less do not necessarily match.

(2) Test Results Tables 1 and 2 show the raw material composition and nutritional value of the test feed. Tables 3 and 4 show the test results. Growth performance during the test period was 1,064g/day gain, 3,087g/day feed intake, and a feed conversion ratio of 2.89. Furthermore, the carcass grading specifications issued at the time of shipment showed that the overall average backfat thickness was 1.32cm, with 1.41cm for castrated males and 1.27cm for females. Approximately half of the 63 piglets (29 pigs) were downgraded due to thin fat (thin back and thin belly). Thirty of the 63 piglets had backfat thicknesses of 1.2cm or less, below the "high" grade range. This test confirmed that piglets born to prolific sows have high weight gain, but low backfat thickness and low carcass grade due to thin fat are a major problem.
In addition, since slight differences were observed in the average back fat thickness between castrated males and females, in the following demonstration experiments, the ratio of castrated males to females in the test and control groups was made as uniform as possible.

Demonstration experiment 2
(1) Test details: The control group was fed a diet similar to commercially available compound feed for fattening swine, while the test group was fed a diet with roughly the same net energy content, crude protein, and lysine content, a crude fat content of 3% by weight or less, and a grain ingredient content of 80% by weight or more. Feed was available ad libitum. A total of 24 piglets from prolific sows were used in the test, with 12 piglets in each group divided into two replicates of 6 pigs each. Growth performance from body weights of approximately 65 kg to 110 kg was compared with the number of pigs judged to be backfat thick and thin-fat, as determined by the carcass grading specifications issued at the time of shipping.

(2) Test Results The raw material composition and nutritional value of the test feed are shown in Tables 5 and 6. The test results are shown in Tables 7 and 8. During the test period, there was almost no difference in growth performance between the test group and the control group in terms of weight gain, feed intake, and daily net energy intake. Furthermore, a comparison was made of the number of animals with backfat thickness and thin fat determined in the carcass grading specifications for 9 of the 12 animals in each group. The test group had slightly lower backfat thickness and a higher number of animals determined to be thin fat. These results suggest that simply increasing the grain content of the feed to 80% by weight or more and the crude fat content to 3% by weight or less will be insufficient to improve backfat thickness or thin fat percentage.

Demonstration experiment 3
(1) Study Contents: The control group received a swine fattening formula feed primarily composed of corn and soybean oil meal. The test group received the same diet, but with crude protein reduced by 3% by weight to 11.5% or less, and lysine supplemented with crystalline amino acids. The net energy content of the diet was slightly higher in the test group. Feed was available ad libitum. A total of 32 piglets from prolific sows were used in the study, with 16 piglets divided into three groups of 5-6 piglets each. Growth performance from approximately 70 kg to 115 kg (until shipment) was compared with the values on the carcass grading sheet issued at shipment. Growth performance from approximately 70 kg to 115 kg was compared with the backfat thickness and number of pigs with thin fat determined on the carcass grading sheet issued at shipment.

(2) Test Results The raw material composition and nutritional value of the test feed are shown in Tables 9 and 10. The test results are shown in Tables 11 and 12. Growth performance during the test period showed higher body weight gain, feed intake, and daily net energy intake in the test group compared to the control group. Furthermore, the back fat thickness and lean fat percentage in the carcass grading specification at the time of shipping showed slightly higher back fat thickness in the test group. On the other hand, the proportion of animals judged as lean fat was higher in the test group. These results suggest that reducing the crude protein content in the diet increases feed intake, which in turn increases body weight gain and daily net energy intake, potentially improving back fat thickness, although not enough to affect the lean fat rating.

Demonstration experiment 4
(1) Test details: A total of 18 prolific sow piglets were fed a diet that contained more than 90% grain by weight and had significantly reduced crude protein and lysine compared to commercially available mixed feed for fattening swine, to confirm whether backfat thickness and the number of pigs judged to be thin fat would improve. The test was conducted twice, with 7 pigs and 11 pigs, and the growth performance from a weight of approximately 70 kg and the carcass grading statement issued by the shipping destination when the pigs were shipped at an average weight of around 115 kg were confirmed.

(2) Test Results The raw material composition and nutritional value of the test feed are shown in Tables 13 and 14. The test results are shown in Tables 15 and 16. Weight gain during the test period was lower than in Demonstration Test 3, confirming that reducing lysine to the level of this test would result in a decline in weight gain. Furthermore, the animals were shipped at an average weight of approximately 115 kg. The backfat thickness and grading criteria in the issued carcass grading specifications showed an average backfat thickness of 1.32 cm, with half of the animals (9 animals) being rated as thin-fat. These results confirm that reducing lysine while simultaneously reducing crude protein in the feed would only worsen weight gain and would not lead to improvements in backfat thickness or carcass grade.

Demonstration experiment 5
(1) Test Details: In contrast to the control group, which received a swine fattening formula feed primarily composed of corn and soybean oil meal, the test group received the same diet, with grain content of 80% by weight or more, crude fat content of 3% by weight or less, total digestible nutrients of 79.0% by weight or more, net energy content of 2,650 kcal/kg or more, crude protein content of 11.5% by weight or less, and lysine supplemented with crystalline amino acids. Feed was available ad libitum. A total of 26 piglets from prolific sows were used in the test, with 13 piglets divided into two groups of 6-7 pigs each. Growth performance from a body weight of approximately 70 kg was compared with the backfat thickness and number of pigs with lean fat determined on the carcass grading specifications issued at the time of shipment.

(2) Test Results The raw material composition and nutritional value of the test diets are shown in Tables 17 and 18. The test results are shown in Tables 19 and 20. During the test period, the test group showed slightly higher body weight gain and higher feed intake than the control group. As a result, the test group showed significantly higher net energy intake per day. Furthermore, the backfat thickness in the carcass grading specifications issued at the time of shipment was approximately 0.5 cm higher on average in the test group than in the control group, and a statistically significant difference was confirmed. Furthermore, no pigs in the test group were judged to be too thin. These results confirmed that the test diet conditions can improve backfat thickness while maintaining body weight gain, and reduce the decline in carcass grade due to thin fat, even in pigs produced by prolific sows with high body weight gain and thin backfat.

Demonstration experiment 6
(1) Test details In Demonstration Experiment 5, it was confirmed that by feeding piglets from prolific sows a compound feed for fattening swine with a diet containing 80% by weight or more of grain, a crude fat content of 3% by weight or less, a total digestible nutrient content of 79.0% by weight or more, a net energy content of 2,650 kcal/kg or more, and a crude protein content of 11.5% by weight or less, it was possible to improve backfat thickness while maintaining weight gain and reduce the decline in carcass grade due to thin fat. In the additional test, for the purpose of confirming reproducibility, it was confirmed whether the same results as in Demonstration Experiment 5 could be obtained if the compounding design was within the scope of the claims. The negative control group was fed a standard swine fattening formula feed consisting primarily of corn and soybean meal, while the positive control and test groups were fed a swine fattening formula feed that met the following requirements: grain content of 80% by weight or more, crude fat content of 3% by weight or less, total digestible nutrients of 79.0% by weight or more, net energy content of 2,650 kcal/kg or more, and crude protein content of 11.5% by weight or less. A total of 69 piglets from prolific sows were used in the test, with 19-20 piglets divided into three groups of 6-7 piglets each. Growth performance from a body weight of approximately 70 kg was compared with the backfat thickness and number of pigs with thin fat determined from the carcass grading specifications issued at the time of shipment.
(2) Test Results The raw material composition and nutritional value of the test diets are shown in Tables 1 and 2. The test results are shown in Tables 3 and 4. During the test period, the positive control and test groups demonstrated higher body weight gain and feed intake than the negative control group. As a result, the positive control and test groups demonstrated significantly higher daily net energy intake. Furthermore, backfat thickness, as measured by the carcass grading specifications issued at the time of shipment, was approximately 0.24 to 0.28 cm higher on average in the positive control and test groups compared with the negative control group. Statistically significant differences were also confirmed between the negative control and positive control groups and between the negative control and test groups. Furthermore, fewer pigs in the positive control and test groups were judged to be low in fat compared with the negative control group. These results confirm that the positive control and test groups' dietary conditions can improve backfat thickness while maintaining body weight gain, even in pigs produced by prolific sows with high body weight gain and low backfat, and reduce the decline in carcass grade due to low fat. This demonstrates the reproducibility of Experiment 5.

<Summary>
By feeding pigs a diet with the following characteristics during the meat pig stage, it is possible to increase backfat thickness while maintaining weight gain, and reduce the decline in carcass grade due to thin fat.
・The proportion of grain ingredients in the compound feed must be 80% by weight or more. ・The crude fat content in the compound feed must be 3% by weight or less, the total digestible nutrient content must be 79.0% by weight or more, and the net energy content must be 2,650 kcal/kg or more. ・The crude protein content in the compound feed must be 11.5% by weight or less, and the lysine content must be 0.60 to 0.90% by weight.

Claims (2)

Formula feed for fattening pork intended for thin-fatted pigs with a backfat thickness of 1.2 cm or less, containing a crude protein content of 11.5% by weight or less, a crude fat content of 3.0% by weight or less, a total digestible nutrient content of 79.0% by weight or more, a net energy content of 2,650 kcal or more per kg of feed, and lysine in the range of 0.60-0.90% by weight. 2. The compound feed for fattening swine according to claim 1, wherein the total proportion of grains in the total feed is 80% by weight or more.