The Observations On Water Stability And Feeding Effect Of Artificial Diet Of Abalone

Purpose:It is necessary to keep water stability of artificial diet of Abalone for more than 4 days. Two artificial diets with sheet shaped of Abalone were studied, the one (diet 1) was manufactured with calender process, the other (diet 2) was manufactured with extrusion technology, and nutritional level were as the same.Therefore, area, volume, mass,dissolved loss rate and swelling rate of two artificial diets of Abalone were observed under seawater with 30‰ of salinity. And ammonia and nitrite nitrogen content of the seawater after soating the diets were measured at 20℃. At the same time, with the two kinds of the feeding trials of abalone were studied that weight, shell length, feed conversion ratio and survival rate of abalone were measured. The main purpose was to detect abalone artificial diets stability in water, to provide information on the environmental impacts of seawater, and to evaluate feeding effect of the diets.Experiment 1:The diet 1 and diet.2 of abalone were placed into the natural seawater respectively and each of six pieces, the seawater conditions for 18℃, thirty percent salinity,30 mm in height. We used vernier calipers measurement the length, width, thickness of abalone artificial feed before 2h、4h、6h、8h、10h、12h、14h、 16h、24h、32h、40h、48h、72h、96h soaking water and after, and calculated the area, volume and quality of feed. The results showed that:with the increase of seawater immersion time, the area, volume and quality of two kinds of abalone artificial diet also will increase, eventually stabilized. Meanwhile, according to the Bertlanffy model analysis about area volume quality changes over time, with the increase of seawater immersion time, the 2nd sheet-extruded feed with increasing immersion time, area, volume and quality of growth are much larger than the 1st calendered sheet-feed, and its breakup time significantly earlier than 1st calendered sheet-feed.Experiment 2:Tests the feed sokaing loss rate and swelling rate in the natural seawater after soaking 8h,16h,24h,32h,40h,48h,72h,96h, the seawater conditions for 15℃,20℃ and 25℃ respectively and thirty percent salinity. Two kinds of feed each set three parallel groups. The results showed that:with the increase of the feed soaking time, two kinds of abalone artificial feed dissolution loss rate and swelling rate rised, rised rapidly within 8h, then leveling off. In terms of dissolution loss rate, in the 15℃ and 20 ℃, the 2nd time flaky puffed feed inflection point time appeared at 3.673 (h) and 2.976 (h), respectively, relative to the first. In terms of time swelling rate, in the 15℃ and 20 ℃, the 1st calendered sheet-feed inflection point time appeared at respectively 1.492 (h),1.388 (h), it was the earliest occurrence time; in the 25℃, on the 1st and the 2nd feed turning point time was 2.820 (h) and 2.665 (h).Experiment 3:Under the conditions of temperature for 20℃, two kinds of abalone artificial feed were weighed 35g in the natural seawater of thirty percent salinity, setted eight gradient time, respectively:Oh,8h,16h,24h,32h,40h; 48h,72h. Two kinds of feed each set of three parallel groups, according to the measured experimental data to establish standard curve. The results showed that:ammonia nitrogen content in the water rised along with the increase of feed soaking time, the rising trend of the second sheet extruded feed was more obvious than the 1st calendered sheet-feed in 0 to 8h. Nitrite nitrogen concentration also increased with the increase of artificial feed immersion time. In 0 to 8h, nitrite nitrogen concentration in seawater increased significantly with the increase of two kinds of models feed immersion time, but after 16h of the soaking time, the concentration of the nitrite nitrogen remained unchanged.Experiment 4:Take a abalone aquaculture farms ranked as the test site, the two kinds of feed in the net two rows of lateral and central, according to a Latin square (1,2,3; 2,3,1 and 3,1,2) for arrangement, each feed set three groups of repetition, each repetition sets six layers breeding cage design, then setted three groups of density gradient box abalone farming a group (string) in six layers, each 100 abalone; 3d to 4d to feed one time, each layer of feeding seven pieces of feed, cleaned up the bait, recorded the death abalone. Trial period for 70 days, Timing observations daily water temperature, salinity, water transparency and other physical and chemical factors, and sampleing measured the 30 youth abalone body weight and shell length every ten days. The results showed that feeding diet 1, the weight of abalone growth rate is 1.15%; Feeding diet 2, the weight of abalone growth rate is 1.00%; The survival rate were 92.7% and 91.8% respectively.Conclusion:Abalone artificial feed immersed in natural seawater, as the change of time, area, volume and quality are increased, eventually stabilised at the same conditions of temperature and salinity; change the soaking temperature under the same conditions of salinity, feed rate and swelling rate of dissolution loss will change with immersion time, the inflection of loss rate of dissolution and the swelling rate exhibits related characteristics; put feed in seawater can increase the content of ammonia nitrogen and nitrite nitrogen, eventually stabilised; abalone artificial feeding promote the growth and development of abalone at a larger degree. The results of the study provide guidance for the improvement of production requirements in abalone artificial feed and daily practice of feeding farmed abalone artificial feed.