JP7254275B2 - Farmed fish feed and farmed fish farming method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a feed for farmed fish and a farming method for farmed fish.

Traditionally, aquaculture of farmed fish such as yellowtail has been actively carried out, and yellowtail has a good fat content and is very delicious, so it is highly evaluated in overseas markets. However, in general, about 48 hours after tightening, the change in meat color of yellowtail, especially the color change from bright red to brown (browning) of the bloody muscle, becomes remarkable, and the commercial value is greatly reduced.

In addition, in recent years, various feeds have been developed to improve the meat quality of farmed fish and promote the growth of farmed fish.

For example, Patent Literatures 1 and 2 below disclose farmed fish feed that can suppress browning after landing and processing by feeding farmed fish.

JP 2016-149964 A JP 2018-29616 A

The farmed fish feeds disclosed in Patent Documents 1 and 2 are feeds containing melon fruits, citrus fruits, hot peppers, etc., but there are also problems such as availability and cost, and it is difficult to give them to farmed fish. Development of a new feed for farmed fish that has an effect of suppressing browning is continuously demanded.

The present invention has been made in view of such problems, and an object of the present invention is to provide a new feed for farmed fish and a method for cultivating farmed fish that can strongly suppress the browning of farmed fish after landing.

In order to solve the above problems, the feed for farmed fish according to the present invention contains 1.5% by mass or more and 5% by mass or less of cacao butter in terms of mass ratio , and is characterized by suppressing browning of farmed fish after landing processing. .

Further, in the method for cultivating farmed fish according to the present invention, a predetermined amount of farmed fish feed containing 1.5% by mass or more and 5% by mass or less of cacao butter and suppressing browning after landing processing of farmed fish is applied to farmed fish. The cacao butter feeding step is characterized by comprising a cacao butter feeding step which is divided into at least 10 days and performed within two months immediately before landing of the farmed fish.

According to the feed for farmed fish according to the present invention, by feeding farmed fish as a feed for farmed fish, it is possible to provide farmed fish in which browning of farmed fish after landing is greatly suppressed.

Further, according to the method for cultivating cultured fish according to the present invention, it is possible to provide cultured fish in which browning after landing is greatly suppressed.

FIG. 1 is a diagram showing measurement results of changes in meat color in each test group in breeding test 1 (20 times of feeding) according to an embodiment of the present invention. FIG. 2 is a diagram showing measurement results of changes in meat color in each test group in breeding test 2 (five times of feeding) according to the embodiment of the present invention. FIG. 3 is a diagram showing measurement results of changes in meat color in each test group in breeding test 2 (10 times of feeding) according to the embodiment of the present invention. FIG. 4 is a diagram showing measurement results of changes in meat color in each test group in breeding test 2 (feeding frequency: 20 times) according to the embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In the present embodiment, a case in which chocolate and cacao butter are mixed with yellowtail farmed fish feed (moist pellets) will be described. Cocoa butter and chocolate containing cocoa butter contain cacao polyphenols, which are polyphenols derived from cacao beans. By mixing these with feed for farmed fish, browning of farmed fish after tightening can be greatly suppressed. can.

(Breeding test 1)
First, breeding test 1 using Example 1 according to the present embodiment will be described. Table 1 shows the composition of Example 1, Comparative Example 1 and Comparative Example 2 of feed for cultured fish used in breeding test 1. Example 1 is a feed containing chocolate, Comparative Example 1 is a feed containing Iyokan pericarp, and Comparative Example 2 is a conventional general farmed fish feed without additives such as chocolate.

Example 1 contains 40% by mass of mixed feed (powder), 40% by mass of raw fish (sand eel), 2% by mass of vitamin preparation (SD Mirame), 8% by mass of feed oil (fish oil), and chocolate. It is a moist pellet produced by mixing 10% by mass. Here, chocolate is a mixture of cocoa butter, sugar, wheat flour, etc., and contains 30% by mass of cocoa butter.

In Comparative Example 1, instead of the chocolate of Example 1, the remaining peel after squeezing the Iyokan fruit juice was crushed and mixed as it was. In Comparative Example 1, the mass ratio is 40% by mass of mixed feed (powder), 40% by mass of raw fish (sand eel), 2% by mass of vitamin preparation (SD slime), 8% by mass of feed oil (fish oil), Iyo Moist pellets produced by mixing 10% by mass of citrus peel.

Comparative Example 2 is a conventional general farmed fish feed without additives such as those in Example 1 and Comparative Example 1, and contains 40% by mass of compound feed (powder) and raw fish (sand eel) in mass ratio. Moist pellets produced by mixing 50% by mass, 2% by mass of vitamin preparation (SD slime), and 8% by mass of feedil (fish oil).

In this breeding test 1, about 5.5 kg 1-year-old yellowtail was divided into 3 test groups of 20 each, and in each test group, the farmed fish feeds of Example 1 and Comparative Examples 1 and 2 were fed once a day. A total of 20 feedings (approximately 5 times per week) were fed over 4 weeks. The feeding amount was 2.6 kg/time in each test group, and the feeding amount/time for one fish corresponded to 2% of the fish body weight in mass ratio. Even with the farmed fish feed of Example 1 mixed with chocolate, yellowtail's appetite for the feed did not decrease.

In addition, in this breeding test 1, after the 4th week (20 times of feeding) after the start of feeding, after landing (3 fish sampled), yellowtail was cut into fillets and stored under refrigerated storage conditions at about 4 ° C. Changes in muscle color were measured. Specifically, the Lab value was measured using a colorimeter (manufactured by Konica Minolta: CR-13), and the degree of browning was evaluated by the b/a value. Measurements were taken every day until 7 days after landing, except for the 6th day.

Next, the results of this breeding test 1 will be described with reference to FIG. In FIG. 1, the horizontal axis indicates the number of days (days) elapsed since the landing, and the vertical axis indicates the b/a value, showing the measurement results of the color change of the landed yellowtail. The b/a value is a value that increases with the progress of browning of the chiai muscle of yellowtail, and it is generally said that a b/a value of 0.8 or less is a guideline for eating raw.

As shown in FIG. 1, in all test plots of Example 1 and Comparative Examples 1 and 2, the b/a value increases as the number of days after the landing process elapses, but the b/a value is less than 0.8. In Example 1, it exceeds 7 days after landing, whereas in Comparative Example 1 it exceeds 5 days and in Comparative Example 2 it exceeds 2 days.

Thus, the yellowtail fed with the farmed fish feed of Example 1 exhibited a meat color (bright red) suitable for eating raw until at least 5 days after landing, and browning could be greatly suppressed. ing.

Browning of Chiai muscle occurs when myoglobin contained in Chiai muscle changes to metmyoglobin (metmyoglobin) through an oxidation reaction. Since this chemical reaction is a kind of oxidation reaction, it can be suppressed by accumulating a certain amount of antioxidant substances in the tissue of the blood vessel.

The chocolate contained in the farmed fish feed of Example 1 contains cacao butter, and the cacao polyphenol contained in this cacao butter has a strong antioxidant effect. Therefore, it is thought that cacao polyphenols taken into the bodies of yellowtails as feed are accumulated in the tissues of the bloody muscle, thereby strongly suppressing browning.

Also in Comparative Example 1, browning was greatly suppressed as compared with Comparative Example 2. This is considered to be due to the antioxidant action of β-cryptoxanthin contained in the Iyokan peel.

Here, looking at the domestic distribution of edible fish, in many cases, it takes about 3 to 4 days from landing to reach the final consumer. If browning can be suppressed for more than one day, it can greatly contribute to distribution in overseas markets.

(Breeding test 2)
Subsequently, breeding test 2 using Examples 1 and 2 according to the present embodiment will be described. Table 2 shows the composition of Example 1, Example 2 and Comparative Example 2 used in breeding test 2. Example 2 is a feed containing cacao butter, and Example 1 and Comparative Example 2 are the same as the feed of Example 1 and Comparative Example 2 used in the breeding test 1 described above.

In Example 2, the mass ratio is 40% by mass of mixed feed (powder), 40% by mass of raw fish (sand eel), 2% by mass of vitamin preparation (SD slime), 8% by mass of feed oil (fish oil), and cacao. Moist pellets produced by mixing 10% by mass of butter.

In this breeding test 2, about 6.5 kg of 2-year-old yellowtail fish were divided into 3 test groups of 20 each, and in each test group, the farmed fish feeds of Examples 1 and 2 and Comparative Example 2 were fed once a day. Each was fed 20 times (approximately 5 times per week) over 4 weeks. The feeding amount was 2.6 kg/time in each test group, and the feeding amount/time for one fish corresponded to 2% of the fish body weight in mass ratio. Even with the farmed fish feed of Example 2 mixed with cacao butter, yellowtail's appetite for the feed did not decrease.

In addition, in this breeding test 2, after the start of feeding, the fish were landed (3 samples) in the 1st week (5 times of feeding), 2nd week (10 times of feeding), and 4th week (20 times of feeding). After that, the yellowtail was cut into fillets and stored under refrigerated storage conditions at about 4°C, and the change in color of the blood muscle was measured. Specifically, the Lab value was measured using a colorimeter (manufactured by Konica Minolta: CR-13), and the degree of browning was evaluated by the b/a value. Measurements were taken every day until 7 days after landing, except for the 6th day.

Next, the results of this breeding test 2 will be described with reference to FIGS. 2 to 4. FIG. In Figures 2 to 4, as in Figure 1, the horizontal axis indicates the number of days elapsed since landing (days), and the vertical axis indicates the b/a value. 3 shows the measurement results of the yellowtail landed in the second week, and FIG. 4 shows the measurement results of the color change of the yellowtail landed in the fourth week.

Referring to FIG. 4 showing the results of feeding 20 times, which is the same as in breeding test 1, the condition where the b/a value exceeds 0.8, which is a flesh color not suitable for raw consumption, is in the test group of comparative example 2. is after the 2nd day after landing, whereas in the test plots of Examples 1 and 2, it is after the 7th day.

That is, in the same manner as in breeding test 1 above, the yellowtail fed with the farmed fish feeds of Examples 1 and 2 exhibited a flesh color (bright red) suitable for eating raw until at least 5 days after landing. It is possible to greatly suppress browning.

Further, referring to FIG. 4, it is considered that the browning suppressing effects of Examples 1 and 2 are almost the same. The chocolate according to the present embodiment contains about 30% by mass of cacao butter, and in Example 1, about 3% by mass of cacao butter is contained in the feed for cultured fish.

In general, the amount of cocoa polyphenols absorbed into the body per day is limited, and even if a large amount of cocoa polyphenols is ingested at one time, it is only excreted from the body. It is

Therefore, it is sufficient that the content of cacao butter, which has an effect of suppressing browning, in feed for farmed fish is about 3% by mass, and the content of cocoa butter in Example 2 (10% by mass) is excessive. I understand.

Furthermore, as will be described later with reference to FIG. 3, in view of the fact that even 10 feeds of the feed for farmed fish according to Examples 1 and 2 exhibit a sufficient effect of suppressing browning, the content of cacao butter in the feed for farmed fish is is 1.5% by mass or more, it is considered that a sufficient effect of suppressing browning can be obtained.

On the other hand, regarding the upper limit of the content of cacao butter in feed for farmed fish, if it is contained in excess, it will only be discharged wastefully, and the amount of mixed feed and raw fish will be relatively small, resulting in growth of farmed fish. For example, it is preferably 20% by mass or less, more preferably 5% by mass or less.

Subsequently, referring to FIG. 3 showing the results of feeding 10 times, in the test plots of Examples 1 and 2, the b/a value exceeds 0.8 on the 4th to 5th days after landing, Even if the frequency of feeding is 10 times in 2 weeks, browning of yellowtail after landing can be sufficiently suppressed by using a cacao polyphenol-containing feed for cultured fish.

In addition, referring to FIG. 2 showing the results of feeding five times, in the test plots of Examples 1 and 2, the b/a value exceeds 0.8 on the third day after landing, and the feeding frequency is 1. In the case of 5 times a week, it can be seen that the absorption of cacao polyphenols is still small, and the effect of suppressing browning is small.

From the above, it is desirable to feed the cultured fish feeds of Examples 1 and 2 10 times or more (10 days or more) in order to obtain a sufficient effect of suppressing browning. By feeding 10 times or more, it is possible to suppress the variation in the intake amount among individuals.

In addition, if the timing of feeding the farmed fish feed added with cacao polyphenols is earlier than the day of landing, there is a risk that the cacao polyphenols that have been absorbed into the fish body and accumulated in muscles, etc., may disappear. Preferably within two months immediately before landing.

As described above, according to the present embodiment, by using a cultured fish feed containing a predetermined amount of cacao butter, it is possible to strongly suppress the browning of yellowtail after landing and processing without inhibiting the growth of yellowtail. It is possible to maintain the product value of the product for a long time.

Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above embodiments, and various modifications are possible without departing from the gist of the present invention. For example, the composition and ratio of the feed for farmed fish can be changed as appropriate, and the timing, amount, frequency, etc. of feeding the feed for farmed fish can also be changed as appropriate.

Further, in the above embodiment, yellowtail was described as an example of farmed fish, but the present invention can be appropriately applied to other fish species such as trout, amberjack, and tuna.

Claims (2)

A farmed fish feed characterized by containing 1.5% by mass or more and 5% by mass or less of cacao butter and suppressing browning of farmed fish after being landed and processed . A cocoa butter feeding step in which a predetermined amount of farmed fish feed containing 1.5% by mass or more and 5% by mass or less of cocoa butter and suppressing browning after landing processing of farmed fish is provided to farmed fish, the step of feeding the farmed fish for at least 10 days. Divided into the above, the farmed fish farming method is characterized by comprising a cocoa butter feeding step performed within two months immediately before landing of the farmed fish.

Images