Juvenile spotted babylon (Babylonia areolata) were obtained from a commercial private
hatchery in Prachuabkirikhan province, Southern Thailand and maintained in the hatchery
at the Research Unit for Completed Commercial Aquaculture of Spotted Babylon, Chulalongkorn
University, Petchaburi province, prior to the feeding experiments. Homogenous
groups of 750 juveniles (initial mean body weight of 1.48 ± 0.06 g per snail) were distributed
randomly into 15 plastic aquaria of 50.0 9 30.0 9 30.0 cm (3 tanks/diet) at a
practical commercial stocking density of 300 snails per m2 (50 snails per tank). Each
rearing tank was supplied with flow-through seawater, and the flow rate was adjusted to
150 l/h. The bottom of the rearing tank was covered with coarse sand of 3.0 cm thickness.
Water depth in the rearing tanks was 20 cm. Each tank was provided with an air stone, and
water was aerated daily for 20 h. to maintain dissolved oxygen levels at or near saturation.
Water temperature and salinity were controlled at 29–31C and 30 ppt, respectively. A
natural photoperiod of 12-h light: 12-h dark was provided. The aquaria and sand substrata
were cleaned biweekly to remove excess food and fecal matter and by scrubbing the sides
of the aquarium. No chemical or antibiotic agent was used during the experiment. Size
grading was not performed throughout the experimental period. The feeding trial was
conducted for 4 months. At the beginning of the feeding trials, each experimental diet was
fed to three replicate groups of snails for 4 months. Juveniles were hand-fed with the
experimental diets once a day (10:00 h) to apparent visual satiation. All groups were fed
their respective diets at the same fixed rate, initially 5% of body weight per day for the first
Table 1 Composition and proximate composition of experimental diets fed to juvenile spotted babylon,
Babylonia areolata
Ingredients (% dry weight) Trash fish Formulated diet
Fish meal – 40.0
Soybean meal – 18.0
Shrimp meal – 3.0
Wheat flour – 17.0
Wheat gluten – 7.0
Tuna oil – 7.0
Vitamin mixa – 2.0
Mineral mixb – 2.0
b-cellulose – 3.0
Proximate composition
Crude protein 19.81 40.31
Crude lipid 1.30 9.18
Ash 1.31 13.71
Carbohydrate 0 4.78
Moisture 77.4 11.17
APD diet animal protein–based diet, VPD diet vegetative protein–based diet, respectively
a Vitamins (% kg-1 diet): vitamin A 107 IU, vitamin D 106 IU, vitamin E 0.01%, vitamin K 0.001%,
vitamin B1 0.0005%, vitamin B6 0.01%, Methionin 0.016%
b Minerals (% kg-1 diet): dicalcium phosphate 14.7%, phosphorus 14.7%, manganese oxide 1.0%, copper
sulfate 0.36%, iron sulfate 0.20%, potassium iodide 0.10%, cobalt sulfate 0.10%, selenium oxide 0.006%
Aquacult Int (2011) 19:865–872 867 2 month and gradually reduced to 3% for the last 2 month. The amount of food was
adjusted weekly based on the amount of food consumed by snails within 0.5 h of the
previous day to ensure that only a minimal amount of food was left. Apparent satiation was
determined from observation of the point at which snails ceased active feeding, moved
away from the feeding area, and buried in the sand substratum. Uneaten food was siphoned
out daily after the snails stopped eating to prevent contamination of water and sand
substratum. The amount of feed eaten was recorded daily for calculation of food conversion
ratios.
Juvenile spotted babylon (Babylonia areolata) were obtained from a commercial private
hatchery in Prachuabkirikhan province, Southern Thailand and maintained in the hatchery
at the Research Unit for Completed Commercial Aquaculture of Spotted Babylon, Chulalongkorn
University, Petchaburi province, prior to the feeding experiments. Homogenous
groups of 750 juveniles (initial mean body weight of 1.48 ± 0.06 g per snail) were distributed
randomly into 15 plastic aquaria of 50.0 9 30.0 9 30.0 cm (3 tanks/diet) at a
practical commercial stocking density of 300 snails per m2 (50 snails per tank). Each
rearing tank was supplied with flow-through seawater, and the flow rate was adjusted to
150 l/h. The bottom of the rearing tank was covered with coarse sand of 3.0 cm thickness.
Water depth in the rearing tanks was 20 cm. Each tank was provided with an air stone, and
water was aerated daily for 20 h. to maintain dissolved oxygen levels at or near saturation.
Water temperature and salinity were controlled at 29–31C and 30 ppt, respectively. A
natural photoperiod of 12-h light: 12-h dark was provided. The aquaria and sand substrata
were cleaned biweekly to remove excess food and fecal matter and by scrubbing the sides
of the aquarium. No chemical or antibiotic agent was used during the experiment. Size
grading was not performed throughout the experimental period. The feeding trial was
conducted for 4 months. At the beginning of the feeding trials, each experimental diet was
fed to three replicate groups of snails for 4 months. Juveniles were hand-fed with the
experimental diets once a day (10:00 h) to apparent visual satiation. All groups were fed
their respective diets at the same fixed rate, initially 5% of body weight per day for the first
Table 1 Composition and proximate composition of experimental diets fed to juvenile spotted babylon,
Babylonia areolata
Ingredients (% dry weight) Trash fish Formulated diet
Fish meal – 40.0
Soybean meal – 18.0
Shrimp meal – 3.0
Wheat flour – 17.0
Wheat gluten – 7.0
Tuna oil – 7.0
Vitamin mixa – 2.0
Mineral mixb – 2.0
b-cellulose – 3.0
Proximate composition
Crude protein 19.81 40.31
Crude lipid 1.30 9.18
Ash 1.31 13.71
Carbohydrate 0 4.78
Moisture 77.4 11.17
APD diet animal protein–based diet, VPD diet vegetative protein–based diet, respectively
a Vitamins (% kg-1 diet): vitamin A 107 IU, vitamin D 106 IU, vitamin E 0.01%, vitamin K 0.001%,
vitamin B1 0.0005%, vitamin B6 0.01%, Methionin 0.016%
b Minerals (% kg-1 diet): dicalcium phosphate 14.7%, phosphorus 14.7%, manganese oxide 1.0%, copper
sulfate 0.36%, iron sulfate 0.20%, potassium iodide 0.10%, cobalt sulfate 0.10%, selenium oxide 0.006%
Aquacult Int (2011) 19:865–872 867 2 month and gradually reduced to 3% for the last 2 month. The amount of food was
adjusted weekly based on the amount of food consumed by snails within 0.5 h of the
previous day to ensure that only a minimal amount of food was left. Apparent satiation was
determined from observation of the point at which snails ceased active feeding, moved
away from the feeding area, and buried in the sand substratum. Uneaten food was siphoned
out daily after the snails stopped eating to prevent contamination of water and sand
substratum. The amount of feed eaten was recorded daily for calculation of food conversion
ratios.
การแปล กรุณารอสักครู่..