Luận văn Nghiên cứu phương thức thay thế thức ăn chế biến trong Ương cá Lóc đen

The experiments were conducted to find out the efficient weaning methods from live food to artificial food in rearing snakeheadmurrel larvae. The first experiment was set up to determine the period of time and methods for effectively weaning artificial food in rearing snakehead murrel larvae. The experiment was randomly set up with 7 treatments with 3 replications. In the control treatment, Moinawas gradually replaced by trash fish with 20% amount of trash fish increase per day. In the other treatments Moina(or trash fish) were gradually replaced by artificial food with 10% or 20% amount of artificial food increase per day, starting on days 10, 17 and 24 post-hatch. The experiment lasted for 5 weeks. The results showed that snakehead murrel larvae can be weaned artificial food at day 17 post-hatch with the replacing method which increased 10% amount of artificial food per day reached survival rate (64,7%) and specific growth rate (SGR=8,89%/ngày) was not significantly (p>0,05) compared to the control. The second experiment based on the optimal results from the first experiment. The objectives of the experiment were to investigate the effects of different attractants on the effective utilization of artificial food at fry stage. The experiment included 4 treatments with 3 replications. The control treatment was done by feeding diet without attractant supplementation. The treatments (2, 3 and 4) were fed diets adding 2% fish protein hydrolysate, 2% squid liver oil and 2% earthworm liquid, respectively. The experiment lasted for 4 weeks. The results showed that 2% fish protein hydrolysate supplied as attractants had significantly higher survival rate (79,3%) and specificgrowth rate (SGR=8,89%/ngày) compared to theother treatments