JPS6335223B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a feed for young flounder in the early stage of hatching, and its purpose is to provide a feed for young flounder that allows for good growth, less occurrence of malformations, and a high survival rate. The present invention relates to a feed for young flounder fish, which is made by supplementing phospholipids with animal and plant plankton and yeast, which are biological feeds. In recent years, artificial seedling production technology for fish and shellfish has been developed, and it has become possible to produce artificial seedlings for various aquatic animals such as red sea bream, sweetfish, prawn, flounder, sea bream, tiger puffer, menada, flatfish, rock flounder, rockfish, rabbitfish, yellowtail, etc. In particular, flounder, like sweetfish, red sea bream, and prawns, is being produced in large quantities by artificial seedlings, and is now being fully farmed. However, this is also due to the mass production of young fish, which are seeds immediately after hatching, and the growth of young fish,
Yield (survival rate) is affected by the growth of healthy seedlings without deformed fish. In the production of these artificial seedlings, most of the initial feed relies on so-called biological feed such as living zooplankton such as the rotifer (hereinafter referred to as rotifer), Artemia, and other microscopic crustaceans, as well as chlorella and diatoms. Cultivation of primary biological feed not only involves problems in terms of management such as facilities, costs, and labor, but also the produced rotifers, Artemia, etc. are nutritionally defective, often resulting in malformations and mass mortality. Rotifers can be produced as high-quality biological feed in a relatively stable manner by multiplying them using highly nutritious marine chlorella.However, there are also problems with culturing marine chlorella, so rotifers are used instead of baker's yeast and marine chlorella. Attempts have been made to mass culture rotifers.
This yeast rotifer has qualitative problems, and in order to improve its nutritional value, attempts have been made to subculture baker's yeast rotifer with marine chlorella for 3 to 12 hours, and to enrich it with ω3 polyunsaturated fatty acids (ω3HUFA). Methods include cultivating rotifers with yeast (fatty yeast enriched with squid liver oil, etc.), and enriching rotifers by emulsifying squid liver oil, which is rich in ω3HUFA, and feeding it directly to rotifers at the same time as baker's yeast. The same method is used for other rotifers such as Artemia. However, the current situation is that there are still problems such as mass mortality and deformed fish in the cultivation of biological feeds such as rotifers and in the production of young fish using biological feeds. Recently, an initial feed containing artificial fine particles has been developed for raising these young fish, and it has been used for sweetfish by administering it alone or in combination with biological feed about 10 days after hatching.
Digestive enzymes are not present in young fish immediately after hatching, and these feeds are not digested and absorbed, causing nutritional problems, and compared to biological feeds, both growth and survival rates seem to be inferior, especially in the early stages. Currently, even biological feed such as rotifers and Artemia,
Further, there is a need for much knowledge regarding the improvement of the growth, survival rate, and malformation rate of young flounder using fine particle initial feeds. As a result of intensive research aimed at improving these conditions, the present inventors found that the growth, survival rate, and malformation rate of young flounder fish fed biological feed such as rotifers and Artemia and yeasts supplemented with phospholipids were significantly improved. I found out that it can be done. Rotifers enriched with ω3HUFA-rich squid liver oil, etc.
The growth and survival rate of young flounder treated with Artemia etc. was also significantly improved compared to the untreated biological feed, but these biological feeds enriched with phospholipids still showed superior growth, It was discovered that the survival rate was shown to be high. In other words, phospholipids can be indirectly used as biological feed by cultivating rotifers and the like with yeast that has been fortified using the method described above, or by feeding rotifers directly to enrich them. By feeding young flounder with supplementary feeding on zooplankton and yeast, extremely excellent effects are shown. Addition of phospholipids is particularly effective for early stage fry when digestive yeasts have not yet developed. Phospholipids are common components of animal and plant cells, are widely distributed in living organisms such as animals, plants, and microorganisms, and are substances that are attracting attention for their physiological effects within the body. As for phospholipids, both chicken egg lecithin and soybean lecithin show excellent growth and survival rates, and all other phospholipids, regardless of animal or plant origin, such as fish eggs and clams, are effective. In particular, excellent effects have been seen with the phospholipid so-called soybean lecithin, which is industrially produced from soybeans at extremely low cost and in large quantities. The amount of phospholipid added varies depending on the feed composition, phospholipid content, etc., but it is preferably 0.001 to 0.02% in terms of phospholipid weight based on the weight of the culture solution of the biological feed. Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Test Examples. Example 1 Chicken egg lecithin and soybean lecithin were each enriched with Artemia, a biological feed, to obtain a biological feed for young flounder. That is, the enrichment was carried out by immersing Artemia hatched larvae for 20 to 24 hours in Rover seawater to which lecithin was emulsified and dissolved together with an emulsifier at a rate of 0.1 ml/ml.
This was done by collecting only Artemia.
(Tested for comparative test) Example 2 3000 Shiomizu rotifers/in a secondary culture tank
ml of bread yeast and squid liver oil,
Soybean lecithin was administered and enriched. i.e. culture solution
100 g of live yeast, 40 ml of squid liver oil, and 40 ml of soybean lecithin were emulsified and administered with an emulsifier per 1 ton, and after subculture for 8 hours, a phospholipid-enriched young flounder fish biological feed from which only rotifers were collected was obtained. Comparative Test Example 1 1000 juvenile flounder fish with a total length of 6 mm were housed in 100 aquariums, and Artemia enriched with chicken egg lecithin from Example 1, Artemia enriched with squid liver oil in the same manner, and untreated Artemia were placed in 100 aquariums. Each was administered and reared for 30 days, and a comparative test was conducted. It is shown in Table 1.

[Table] Comparative test example 2 1,500 young flounder with a total length of 3.4 mm were housed in 30 aquariums, and rotifers enriched with soybean lecithin from Example 2 and rotifers treated with no lecithin were fed and reared for 16 days for comparison. Tested. It is shown in Table 2.

[Table] Comparative Test Example 3 500 young flounder with a total length of 5 mm were housed in 50 aquariums, and the soybean lecithin-enriched rotifers of Example 2 were administered for 10 days, and then the soybean lecithin of Example 1 was administered. Artemina enriched with was administered for 24 days and kept for a total of 34 days. Similarly, a comparative test was carried out by administering untreated Shirtemia for 10 days and then administering untreated Shirtemia for 24 days.

【table】

Claims (1)

[Claims] 1. Feed for young flounder fish, which is made by supplementing phospholipids with animal and plant plankton and yeast, which are biological feeds.