生物絮团系统(BFT)中PHBV为碳源对斑点叉尾鮰生长、水质及硝化反应的影响

Effect of PHBV on growth,water quality and nitrification of Ictalurus punctatus in biofloc technology system(BFT)

为了研究生物絮团系统(BFT)中以3-羟基丁酸-co-3-羟基戊酸共聚物(PHBV)为碳源对斑点叉尾鮰(Ictalurus punctatus)生长、养殖水质及对硝化过程反应速率及硝化酶的影响,设置不添加PHBV组(CL组)和挂袋300 g PHBV颗粒组(PHBV组)进行29 d的养殖实验,每4 d检测水质、絮团指标。实验结束检测鱼体生长指标,取实验末养殖水进行10 mg/L NH+4降解连续监测,取特征点总氨氮(TAN)最高(A),亚硝酸盐(NO2^--N)最高(B1/B2)及硝酸盐(NO3^--N)最高(C)时的絮团样检测氨单加氧酶(AMO)、羟氨氧化还原酶(HAO)及亚硝酸氧化还原酶(NOR)含量。结果显示:两组的成活率、增重率、特定增长率以及饲料系数均无显著差异,PHBV对斑点叉尾鮰鱼苗生长促进不显著。整个养殖过程中两组TAN、NO2^--N均处于安全范围,硝酸盐、磷酸盐、总氮、总磷及总固体悬浮物与絮团体积均呈现不断积累的趋势,且两组将10 mg/L NH4^+转化为NO3^--N均需约28 h,表明两组生物絮团性能良好。硝化酶结果显示,PHBV组的AMO、HAO及NOR含量均显著大于CL组,但其硝化速率并未显著提高。两组游离菌的AMO、HAO、NOR含量均显著低于固着菌,且CL组游离菌中AMO、HAO及NOR含量与PHBV组差异不显著。

This experiment was divided into two groups to study the effect on water quality,nitrifying rate and enzyme after adding PHBV to biofloc technology system(BFT).The first group was CL group without PHBV,the second group was PHBV group,which hung PHBV(300 g)with bags.The Ictalurus punctatus fingerlings were cultured for 29 days.During the experiment,the water quality and floc index were detected every four days,at the end of experiment weight the fish and the final culturing water was taken for continuous monitoring of degradation of 10 mg/L nitrogen.The content of AMO,HAO and NOR was detected by floc samples when TAN was the highest(A),NO2^- -N was the highest(B 1/B 2)and NO3^- -N was the highest(C).The results showed that there was no significant difference in survival rate,weight gain rate,specific growth rate and feed coefficient between the two groups.PHBV had no significant effect on the growth of I.punctatus.Both of TAN and NO2^- -N were at a low level in the whole culturing process,and NO3^- -N,PO4^3-,TN,TP,TSS and FV of the two groups showed a trend of continuous accumulation.It took about 28 hours for the two groups to convert 10 mg/L NH4^+ into NO3^- -N,indicating that the flocs of two groups had excellent performance.The results of the nitrifying enzyme showed that the content of AMO、HAO and NOR in PHBV group was significantly higher than that in CL group,but the nitrification rate was not significantly increased.Besides,the content of AMO,HAO and NOR in the free bacteria of the two groups were significantly lower than that of the fixed bacteria,and the content of AMO,HAO and NOR in the free bacteria of the CL group were no significant difference with PHBV group.