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Evaluation of the performance of abalone foods available in the market Shin-ichi Yasuda, Hirofumi Kotani, Jun Kono, and Takashi Hara*
29 March 2004
Abstract
* Oita Ocean Research Centre
1 Background
AA share in Australian abalone foods market is 90 %. They have originally been producing the foods for greenlip Haliotis laevigata which lives in Australia. In Japan, JIFAS have used AA in their test enterprise in collaboration with Hokkaido University. As of the end of 2001, AA's food is sold in Australia at A$3 per 1 kg (which is 4080 JPY for 20 kg at 1 AUD = 68 JPY), approximately half of Japanese abalone foods. This price di_erence motivated us to evaluate the performance of three different abalone foods on Ezoawabi; one is from AA, other two are from Japanese market (Cosmo Ocean Pasture and Japan Agriculture Industry). Table 1: General composition analysis. Bracketed values were equivalent dry weight percentage.
2 Material and Methods 2.1 Material On 10th June 2003, five hundred abalone (length 2 cm each) fry were purchased from Kamiho Branch, Oita Bureau of Fishery. In summer when sea weeds are of plenty, Arame Eisenia bicyclis, Aosa Ulva pertusa, and theabalone foods produced by Cosmo Ocean Pasture were used. In winter just prior to the test, only the abalone foods were used. Just before the test, each abalone weighed 19.58_3.50 g with the shell length is 54.91_2.90 mm. Ten individuals were kept in a flume and two flumes (20 individuals) were employed for each condition. In the present test, each abalone is labeled with a number. A piece of TEPRA PRO tape with printed number is attached to the abalone shell with an adhesive. During the measurements, 2.4% ethanol was used for anaesthesia.
2.2 Foods
Among the three kinds of foods, the abalone food from Cosmo Ocean Pasture ("COP", henceforth) was purchased from Oita Bureau of Fishery along with the abalone fry. Abalone food of Japan Agriculture Industry ("2N", henceforth) was provided by Shizuoka Prefecture Fishery Institute. A&A’s 7 mm chip was purchased via JIFAS. Plate 1 shows the photograph of AA and Table 1 is the result of general composition analysis. The general composition analysis has been performed in Japan Food Analysis Center. The methods used were the room pressure heated dry method for water, Kerdaar (with nitrogen protein conversion coeficient 6.25) method, the acid decomposition diethylether distillation method for fat, the filltering method for fibre, the direct ash-ize method for ash. The dissolve non-nitrogen is 100-(water+protein+fat+fibre+ash).
It can be seen that AA has less protein, less-than-half fat, fibre, and ash than the other two. On the other hand, dissolve non-nitrogen is higher, more than 50 %.
Plate 1 A&A 7mm Chip
Table 2: Conditions for Ezoawabi
2.3 Devices and conditions
Plastic flumes were used (40x60x30cm(H), 55 litre). As shelters, two of 25 cm piece of PCV gutter were placed inside. Table 2 shows the conditions. The test started on 1st Feb 2004 and finished on 22nd March with final measurements. During the test, the water temperature was approximately at 14oC, which is somewhat below the generally agreed appropriate temperature for abalone of 15oC to 23oC. Abalone's growth was, however, satisfactory.
2.4 Feeding method
In this test, the abalones were fed once in the afternoon to evening, 2g to 3g per one flume. The residue was cleaned in the next morning. 2N was consumed more than the other two and when no residue was found, the feeding amount is increased as 2g® 2.5g® 3g per flume. COP and AA were always fed at 2g per flume. The residual food and excreta were cleaned every morning with a thin PCV pipe and 30 mesh basket. The excreta on the net were collected manually with a pair of tweezers and stored frozen. Every 10 days, the stored excreta were processed with vacuum dry freezer and weighed.
Table 3: Evaluation of market food Weight (g) Shell length (mm)
2.5 Food consumption
The amount of food consumption is calculated by (food consumption) = (food (dry)) - (excreta (dry)). Feed conversion efficiency (FCE) is calculated by (FCE) = (weight increase (wet g)) / (food consumption (dry g)) x 100 (%). Meat increase coefficient is given by (MIC) = (food consumption (dry g)) / (weight increase (wet g)).
3 Result and discussion
3.1 Market food and growth
After 50 days of experiment, the growth is described in Table 3 and Figures 1 and 2. (Figures 1 and 2 omitted.) All abalone survived. Therefore it is confirmed that it is possible to raise abalone in Oita Marine Science Center even in the middle of winter. From the above Table and Figures, it is concluded that 2N promotes the growth most, and the performances of COP and AA are almost equal. Because sample Ezoawabi had been fed with COP until just before the tests, it was feared that they did not feed on AA, but it is found that they do feed on AA sufficiently.
3.2 Market food and efficiency
In each flume, the food conversion efficiency (FCE) and meat increase coefficient (MIC) are calculated and shown in Table 4. Table 4: Evaluation of market food (1 Feb 2004 | 22 Mar 2004)
It is remarkable that FCE of AA is as high as 96 %, which shows that the quality abalone food of ADAM & AMOS is as good as the domestic food such as COP and 2N.
Japan Agriculture Industry started marketing the abalone food since 1977, or 27 years ago. They sold approximately 300 tons of the abalone food in 1993. It has been reported that the abalone food of Japan Agriculture Industry is superior in food consumption and growth rate to the abalone food from Deakin University (Australia) in the test with blacklip Haliotis rubra - a kind of abalone. In the present test, the food of Japan Agriculture Industry showed clearly more consumption and more growth rate than those of ADAM & AMOS and Cosmo Ocean Pasture.
There have been known 70 kinds of abalone in the world oceans and 20 of them are industrially important. In Japan, Ezoawabi is found mainly in the north of Ibaraki Prefecture and Kuroawabi in the south of Chiba Prefecture. Since Ezoawabi is resistant to diseases and fry production is easy, they have been cultivated in Oita since around 1988. In Australia, blacklip and greenlip are well-known. The latter grows faster and it is believed that greenlips sell better in Chinese markets. The blacklip and greenlip are found from South Australia to Tasmania. The abalone catch in Australia is more than 5000 tons, of which Japan imports about 500 tons (537 tons in 2000). The abalone catch in Japan is approximately 2000 tons. A statistics shows that nearly 3000 tons of abalone are consumed in Japan in one year. In Oita prefecture, the abalone catch in 2001 is 43 tons. The amount of reseeded fry increases, but the catch is decreasing. Today's situation is often said as "no increase even if discharged". The decrease of the domestic catch is covered by the increase of cheap imported abalone. The distribution of world abalone coincides with that of kelp. In the northern hemisphere, the east coast of Asian continent, the west coast of North America, and the west coast of Europe continent. In the southern hemisphere, the southern coast of Australia, the coast of New Zealand, and the southern tip of Africa. Abalones feed on kelps (Konbu, Wakame, Arame, and Giant Kelp), and they also need rocks and rolling stones to dwell, which limits their distribution. The appropriate temperature for abalones are between 15 oC to 23o, of which the range between 17oC to 20o is best for growth. Japanese coastal seas are not ideal for abalone cultivation because they are too cold in north in winter and too warm in south in summer. Moreover, Japanese production of abalone fry is often aimed at reseeding or intermediate growth, thus difficult to change to cultivation. The reason for "no increase even if reseeded" is believed to be threefold; over-predation, illegal fishing, and over-fishing. The success of the abalone cultivation depends on 1. appropriate temperature and quality of water, 2. economical food, 3. broodstock of good quality, and 4. prevention of disease. The economical food is often a "binder", that is, the food easy to consume and hard to dissipate. It is well-known that growth is better with artificial food than with the natural kelp. Abalone's MIC (meat increase coefficient) is 15 to 20 with the natural kelp, i.e., for 1 kg of the abalone growth, as much as 15 kg to 20 kg of kelp is necessary. In addition, the kelp is available only in certain seasons. The food of ADAM & AMOS which has 90 % share in the Australian market is priced at 4080 JPY for 20 kg, while domestic food is more than 10000 JPY for 20 kg. Japanese successful cultivators of abalone use plenty of local and natural kelp and use minimum artificial food only when natural kelp is unavailable, probably because the cost would be excessive if only the artificial foods were used. It seems essential in Japan to develop economical artificial food that not only enables high consumption and high growth rate, but also supports the abalone cultivation industry which produces abalone of top quality.
Acknowledgements The authors thank Mrs. Taniguchi and Mozquiera from JIFAS for providing us with the ADAM & AMOS abalone food. References See Japanese version. |
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