by
ABSTRACK
The experiment was conducted in 60 liters aquaria filtered seawater at the Research Institute for Coastal Water Karangantu Serang, West Java on August 1981 and May 1982.
The aim of this study was to clarify the optimum level of protein contents by making a rearing experiment using feed of different contents of protein.
Four kinds diets of different protein contents namely : 58 %, 46 %, 35% and 29% were provided and offered to the Siganus javus of 4.79 g and Siganus canaliculatus of 0.49 g in average body weight, respectively. Feed were given to a satiation four times daily.
During the six weeks experiment, the water temperature was ranged of 28.3 – 29.4°C and pH of sea water was ranged of 7.70 – 8.02. Siganus javus showed better growth in feed containing the protein of 35% to 46%. However, Siganus canaliculatus, fed by 58% protein contents showed rapid growth from the begining of experiment.
INTRODUCTION
The food requirement of siganids in mariculture had been investigated by TSUDA and BRYAN (1973) : VON WESTERNHAGEN (1973).
In order to develop methods for large scale culture of Siganids, which are highly esteemed food fish in the Indo - Pacific region, it is essential to determine feeding and rearing techniques under culture conditions (VON WESTERNHAGEN et al. 1976). VON WESTERNHAGEN (1974b), VON WESTERNHAGEN and ROSENTHAL (1975) reported on the primarily trials using commercial foods, resulted that, a good survival and growth of experimental rabbitfish which were fed hourly for nine hours a day with pelleted mixed with chicken and rabbid feeds.
Siganids fishes are herbivorous species and can be cultured by feeding food containing lower protein contents as compared with the other fish species and attention has been paid to them as object fish for mariculture.
The study was aimed to clarify the optimum level of protein in terms of their growth by food of different crude protein.
MATERIALS AND METHODS
Fish fry for the experiment were obtained from the Bojonegara zosterazone. These fry were used for rearing experiment after they had been preliminarly reared in the net cage by feeding in the mixed feed containing diet for carp and minced fish.
1) Research Institure for Coastal Aquaculture, Karangantu - Serang.
2) Expert of Japan International Cooperation Agency (JICA).
The experiment was used two kinds of siganus species, on the first trials was Siganus javus of 4.79 gram in average body weight, and for the second trials was Siganus canaliculatus of 0.49 gram in average body weight. (Table 1).
Table 1. The number and size of Siganus javus and Siganus canaliculatus used in the experiment fed by different protein contents.
| FOOD NO. | S. javus | S. canaliculatus | ||||||
| 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 | |
| FISH No. | 20 | 20 | 20 | 20 | 33 | 33 | 33 | 33 |
| A.B.W. (g) | 4.69 | 4.74 | 5.29 | 4.43 | 0.48 | 0.49 | 0.46 | 0.52 |
| T.B.W. (g) | 93.80 | 94.80 | 105.80 | 88.60 | 15.84 | 16.17 | 15.18 | 17.16 |
A 60 - liters aquaria with circulating filtration system was used for rearing the fish fry in four treatments. A mixture of sodium bicarbonate (NaHCO3) and sodium carbonate (Na2CO3) was added to control the pH of sea water.
The feed used for experiment was provided in four kinds of crude protein level, these feeds were made from the Japanese diets for sea breams and mixed up with wheat flour (50%), tapioka starch (25%) and sagu starch (25%). To which a mixture of vitamins and minerals was added. (Table 2).
Table 2. The composition of feed used in the experiment for Siganus javus and S. canaliculatus
| Ingredient (g) | Feed No. | Total (g) | |||
| 1 | 2 | 3 | 4 | ||
| Compound feed | 1000 | 750 | 530 | 420 | 2700 |
| for Sea bream | (100%) | (75%) | (53%) | (42%) | |
| Flour *) | - | 250 | 470 | 580 | 1300 |
| (25%) | (47%) | (58%) | |||
| Vitamin | 20 | 20 | 20 | 20 | 80 |
| (2%) | (2%) | (2%) | (2%) | ||
*) Composition of Flour is : Wheat flour 50%
Tapioka starch 25 %
Sagu starch 25 %
The compound feed was then analysed chemically by the Research Institute for Freshwater in Bogor. (Table 3). Those compound feed was made into crumbles of about 1 mm, 1.5 mm and 2 mm in diameter by using a sieve.
During the six weeks, feed were offered to satiation four times daily at 08 : 00, 11 : 00, 13 : 00 and 17 : 00 respectively. Water temperature and pH were observed daily at 08 : 00 and 13 : 00.
The total length and body weight were measured every two weeks, in case of body weight measurement was used and analytical balance (Libror E.D - 200 Shimadzu).
Table 3. The chemical analysis of compound feeds, which were used in the experiment.
| INGREDIENT (%) | FEED NO. | |||
| 1 | 2 | 3 | 4 | |
| Moisture | 12.42 | 12.25 | 11.94 | 12.45 |
| (0.8758) | (0.875) | (0.8806) | (0.8755) | |
| Crude protein | 58.79 | 46.63 | 35.26 | 29.64 |
| (51.49) | (40.80) | (31.05) | (25.95) | |
| Fat | 2.67 | 2.67 | 2.00 | 2.00 |
| (2.34) | (2.33) | (1.76) | (1.75) | |
| Ash | 16.23 | 12.29 | 8.81 | 4.59 |
| (14.22) | (10.75) | (7.76) | (4.42) | |
| Crude fibre | 0.12 | 1.86 | 0.88 | 0.50 |
| (0.11) | (1.63) | (0.77) | (0.49) | |
| Calcium | 0.80 | 0.79 | 0.83 | 1.70 |
| (0.70) | (0.69) | (0.73) | (0.61) | |
| Phosphate | 2.40 | 1.81 | 1.44 | 1.27 |
| (2.10) | (1.58) | (1.27) | (1.11) | |
Those in brackets are the wet base value.
RESULTS AND DISCUSSION
Siganus javus fry showed better growth in feed containing the protein contents of 35% to 46 %, despite the fact that feed of high protein contents showed comparatively good results at the initial stage of the experiment. However, that of Siganus canaliculatus fed by diets containing 58% protein was better in growth. Their growth become dull according they grew. Feeding activity was inactive among fish by the feed of high protein content since the beginning of the experiment.
According to TSUDA and BRYAN (1974), their experiment showed that Siganus canaliculatus after 42 weeks fed by Entermorpha and trout chow (containing 40% protein) increased in weight from 0.5 g to 65 g. Those was nearly double the weight of those fishes fed by diet consisting only of Enteromorpha (containing of about 11 – 27 % protein).
In these study may be similar to those phenomenon, for Siganus canaliculatus their growth faster by food containing 58% protein than those fed by diet containing only 29% protein. However, their feeding activity was inactive. In term of growth it may be different by species, Figure 1 showing the growth of S.javus; fishes fed by 58 % protein was lower than those fed by 35 % or 46 % protein.
During the experiment the water temperature ranged of 28.3 – 29.4°C. and pH of sea water ranged of 7.70 – 8.02.
| Period Food no | Aug 24 th 1981 | Sep 7 th 1981 | Sep 21 th 1981 | Oct 4 th 1981 | ||||||||||||
| 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 | |
| Fish no | 20 | 20 | 20 | 20 | 19 | 20 | 20 | 20 | 19 | 20 | 20 | 20 | 19 | 20 | 20 | 20 |
| A.B.W. (g) | 4.69 | 4.74 | 5.29 | 4.43 | 6.90 | 7.10 | 7.14 | 6.06 | 9.49 | 10.08 | 10.00 | 8.60 | 11.50 | 12.75 | 13.00 | 10.50 |
| T.B.W. (g) | 93.90 | 94.80 | 105.90 | 88.70 | 131.30 | 142.90 | 142.90 | 121.30 | 180.40 | 201.60 | 200.00 | 173.70 | 218.50 | 255.00 | 260.00 | 210.00 |
| Mortality | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | ||||
| Total food (g) | 50.00 | 61.00 | 74.10 | 66.00 | 91.40 | 113.20 | 132.20 | 124.50 | 100.30 | 120.20 | 140.70 | 121.60 | ||||
| F.C.R. | 1.34 | 1.29 | 2.00 | 2.02 | 1.86 | 1.90 | 2.32 | 2.30 | 2.63 | 2.25 | 2.34 | 3.35 | ||||
| D.F.R. | 3.16 | 3.60 | 4.26 | 4.49 | 4.08 | 4.71 | 5.51 | 6.03 | 3.59 | 3.76 | 4.37 | 4.53 | ||||
| D.G.R. | 2.72 | 2.85 | 2.13 | 2.22 | 2.26 | 2.40 | 2.80 | 2.54 | 1.37 | 1.67 | 1.86 | 1.35 | ||||
Remarks : A.B.W. = Average body weight
T.B.W. = Total body weight
F.C.R. = Food conversion ratio
D.G.R. = Daily growth
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| Period Food no | May 6th 1982 | May 24 th 1982 | June 7 th 1982 | June 24 th 1982 | ||||||||||||
| 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 | |
| Fish no | 33 | 33 | 33 | 33 | 32 | 32 | 30 | 32 | 32 | 31 | 28 | 32 | 25 | 26 | 28 | 29 |
| A.B.W. (g) | 0.40 | 0.49 | 0.46 | 0.52 | 1.30 | 1.10 | 0.97 | 0.92 | 3.16 | 2.55 | 2.19 | 1.79 | 4.26 | 3.74 | 3.30 | 2.71 |
| T.U.W. (g) | 41.74 | 35.20 | 29.05 | 29.59 | 101.00 | 78.00 | 60.14 | 57.30 | 106.50 | 97.74 | 77.79 | 78.67 | ||||
| Mortality | 1 | 1 | 3 | 1 | 0 | 1 | 2 | 0 | 7 | 5 | 5 | 3 | ||||
| Total food (g) | 26.42 | 25.01 | 23.14 | 27.26 | 80.03 | 67.54 | 57.57 | 60.52 | 123.30 | 107.40 | 97.10 | 103.30 | ||||
| F.C.R. | 1.03 | 1.36 | 1.69 | 2.21 | 1.34 | 1.55 | 1.05 | 2.10 | 1.16 | 1.10 | 1.25 | 1.29 | ||||
| D.F.R. | 5.07 | 5.54 | 5.78 | 6.47 | 8.01 | 8.39 | 9.09 | 9.97 | 6.86 | 7.05 | 8.18 | 8.68 | ||||
| D.G.R. | 5.12 | 4.26 | 3.96 | 3.07 | 5.96 | 5.67 | 5.40 | 4.59 | 1.74 | 2.22 | 2.62 | 2.40 | ||||
Figure 1. The growth of Siganus javus, reared in 60 - liters aquaria fed by diets of different protein contents.
Figure 2. The growth of Siganus canaliculatus, reared in 60 liters aquaria fed by diets of different protein contents.
REFERENCES
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MAY ROBERT C. DAN POPPER and JAMES P.Mc. VEY. 1974. Rearing and larval development of Siganus canaliculatus (Park) Pisces; Siganidae). Micronesia 10 (2); 225 – 298.
TOBTAS W.J., PATRICK G. BRYAN, WILLIAM. J. FITZGERALD, Jr. 1976. Studies on the genus Siganus (Rabbitfish) in Guam waters. University of Guam Marine laboratory. Technical report no. 37.
TSUDA ROY T., PATRICK G. BRYAN. 1974. Juvenile-Adult rearing of Siganus (Pisces : Siganidae) in Guam. University of Guam Marine Laboratory. 19 – 25.
VON WESTERNHAGEN, H. 1973. The natural food of the rabbitfish Siganus oramin and Siganus striolata, Marine Biology 22; 267–370.
VON WESTERNHAGEN, H. 1974. Food preferences in cultured Rabbitfishes (Siganidae). Aquaculture 3 ; 109 – 117.
VON WESTERNHAGEN, H. and ROSENTHAL, H. 1976. Induced multiple spawning of reared Siganus oramin (Schneider) (= S. canaliculatus Park). Aquaculture, 7; 193 – 1986.
