Study On PH And Salinity Control Technologies Of Biofloc-based Shrimp Culture Environment

This paper preliminary studies the influence of environment change on breeding effect in BFT, in order to establish a reasonable and efficient bio-floc shrimp farming environmental control technology. Besides, a study on the impact of reducing bait for the vannamei farming in BFT in large pood outdoor. Mainly discussed (1) Research on the pH regulation technology of bio-floc environment in BFT; (2) Research on the salinity regulation technology of bio-floc environment in BFT; (3) Research feeding levels on the application effect of shrimp (Litopenaeus vannamei) farming with BFT. The main results were as follows:1 Study on the pH regulation technology of biofloc environment in BFTThis paper studied effects of the control of pH on water quality, bio-floc nutrition, active substances, extracellular enzymes, growth and the health status of shrimp (L. vannamei) reared in zero-water exchange biofloc-based culture tanks. In order to establish the pH control technology in BFT, to provide scientific references for vannamei farming in BFT. Experimental setup for the five treatment groups:Four pH treatments and one control were compared:TO—control, T1—pH 7.6—NaHCO3, T2—pH 7.6—Na2CO3, T3—pH 8.1—NaHCO3, T4—pH 8.1—Na2CO3, and each treatment consisted of three repeats. The results show that:The water quality, bio-floc nutrition, active substancesthe, extracellular enzymes, the growth and the health status of shrimp (L. vannamei) had a significant difference between among treatments in control of pH in BFT. Thus, the control of pH in BFT has a significant impact on water quality, bio-floc nutrition, active substances, extracellular enzymes, growth and the health status of shrimp. It is necessary to adjust the pH and alkalinity in the BFT, and a higher pH and alkalinity for shrimp growth and the stability of the BFT are more favorable.2 Study on the salinity regulation technology of biofloc environment in BFTThis paper studied effects of the control of salinity on water quality, bio-floc nutrition, active substancesthe, extracellular enzymes, growth and the health status of shrimp (L. vannamei) reared in zero-water exchange biofloc-based culture tanks. In order to establish the salinity control technology in BFT, to provide scientific references for vannamei farming in BFT. Experimental setup for the three treatment groups:the salinity of control group was 31, the aquaculture water salinity from 31 mutation to 25 and 22 by adding the boldness of drinking water, then adjusted to 31 as the amplitude of increase 2/and 3/d, respectively, and stabled at 31 for 3 days, the change process was repeated three times. The results show that:The water quality, bio-floc nutrition, active substances, extracellular enzymes, the growth and the health status of shrimp (L. vannamei) had a significant difference between treatments and control in control of salinity in BFT. Thus, the control of salinity in BFT has a significant impact on water quality, bio-floc nutrition, active substances, extracellular enzymes, growth and the health status of shrimp. It is best to maintain a relatively stable salinity in BFT and mutations of salinity do not exceed 6, otherwise the growth of shrimp and stability farming systems will be impacted badly.3 Study feeding levels on the application effect of L. vannamei farming with BFTThis paper studied effects of different feeding levels on shrimp (L. vannamei) framing actual in large outdoor pool with BFT. Carbon source was added in the aquaculture water (molasses) to develop biological floccules, and control the C/N to 12. Experimental setup for the two treatment groups:100% bait casting group,70% bait casting group, and each treatment group set up two parallel groups. The results show that:Reducing the bait casting of biological floccules breeding had no significant effects on water quality, growth of prawn, physical health and farming efficacy. Thus, Reducing the bait casting for lower feed conversion rates reasonable in farming vannamei shrimp with bio-floc can not only maintain normal growth, but also to maintain normal physiological health of shrimp, or even slightly higher. Besides, it also can improve the input-output ratio and increase economic benefits of aquaculture. Therefore, a reasonable reduction in the amount of feeding will not affect the farming vannamei actual production with bio-floc.