Effects of sterilization at different temperatures and addition of probiotics on the number of marine sediment colonies and nutrient diffusion flux
In the cultivation of shrimp,the use of sandworms as high quality bait often carry pathogenic Vibrio and lead to outbreaks of shrimp disease;therefore,the risk of carrying pathogenic Vibrio is expected to be reduced by sterilizing the aquaculture environment of sandworms.Based on the biological characteristics of the pathogenic Vibrio,this study was conducted to explore the sterilization effects on sediment at different temperatures(65 ℃for 30 min,100 ℃ for 30 min,and 121 ℃ for 20 min)and the effects of adding probiotics on the physical and chemical indexes of sediment.The results showed that the immediate sterilization results of each temperature sterilization group were good.The sterilization rate of the total colonies in the sediment was 57.5％for 65 ℃-30 min,99.45％for 100 ℃-30 min,and 99.99％for 121 ℃-20 min,respectively.This showed that with an increase in sterilization temperature,the sterilization rate gradually increased,and the sterilization rate for the pathogen Vibrio reached 100％.Analysis of the physicochemical indexes of the sediment showed that with the increase in sampling time,the influence of the sterilization treatment on the nitrogen-phosphorus diffusion flux at the sediment-overlying interface decreased,and the addition of probiotics could reduce the NO3-and PO43-concentrations in the water and sediment.There were significant differences in the NO3-and PO43-diffusion flux between the probiotic and non-probiotic groups at the same sampling time(P＜0.05).The study showed that all Vibrio bacteria in the sediment could be killed at 65 ℃ for 30 min,and no pathogenic Vibrio colonies were detected during the whole experiment.The addition of probiotics could optimize the sediment colony structure,inhibit the increase in total colony number,and affect the nitrogen-phosphorus diffusion flux at the sediment-overlying interface.These findings provide a reference for the application of sediment sterilization and probiotic preparation in aquaculture.
temperature treatmentsterilizationprobioticssedimentation
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