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首页> 外文期刊>Aquaculture >Dietary carbohydrate composition can change waste production and biofilter load in recirculating aquaculture systems.
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Dietary carbohydrate composition can change waste production and biofilter load in recirculating aquaculture systems.

机译：膳食碳水化合物的组成可以改变循环水产养殖系统中的废物产生和生物滤池负荷。

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This study investigated the effect of dietary carbohydrate composition on the production, recovery and degradability of fecal waste from rainbow trout (Oncorhynchus mykiss) in recirculating aquaculture systems (RAS). Dietary carbohydrate composition was altered by substituting starch with non-starch polysaccharides (NSP) while keeping the diets isonitrogenous and isoenergetic. We tested a high starch, low NSP (LNSP) and a low starch, high NSP (HNSP) diet in six identical, small-scale RAS (V=460 L). Each diet was tested in three independent systems over a period of six weeks. Shifting dietary carbohydrates from starch to NSPs resulted in a 50% increase in the production of chemical oxygen demand (COD) based on digestibility. Fecal waste recovery showed a 40% increase in HNSP treatments when compared with LNSP. Consequently, the COD output from HNSP systems doubled from 91 g to 194 g of COD per kg feed when compared with LNSP. Although COD production was higher in HNSP systems, the COD load on the biofilters was significantly lower when compared with LNSP systems. COD-to-nitrogen (COD/N) ratios in the biofilter load were 1.7+or-0.2 and 2.2+or-0.2 g COD/g N for HNSP and LNSP, respectively. Shifting the dietary carbohydrate composition from starch to NSPs decreased the biodegradability of fecal COD from 66.3% to 43.7% (P<0.001). Fiber analyses revealed that approximately 40% of the COD in HNSP feces came from cellulose and hemicellulose. The increased COD production of HNSP diets could be exploited by using fecal COD as an internal carbon source in denitrification. Full denitrification would be theoretically possible with a measured COD/N ratio of 7.2 in the waste stream of HNSP systems. However, it is not clear if the low COD bioavailability of HNSP feces could be a limiting factor. This study shows that COD/N ratios in the biofilter load and system output can be manipulated by changing dietary carbohydrate composition. Although an increased dietary NSP content increased COD production, it also increased COD recovery, decreased COD load on the biofilters and generated sufficient carbon for denitrification on internal sources.
机译：这项研究调查了膳食碳水化合物成分对循环水产养殖系统（RAS）中虹鳟（Oncorhynchus mykiss）粪便产生，回收和降解的影响。通过用非淀粉多糖（NSP）代替淀粉，同时保持饮食中的等氮和等能，改变了饮食中碳水化合物的组成。我们在六个相同的小规模RAS（V = 460 L）中测试了高淀粉，低NSP（LNSP）和低淀粉，高NSP（HNSP）饮食。每种饮食在三个独立的系统中进行了为期六周的测试。将膳食碳水化合物从淀粉转变为NSP导致基于消化率的化学需氧量（COD）产量增加​​了50％。与LNSP相比，粪便废物回收率显示HNSP处理增加了40％。因此，与LNSP相比，HNSP系统的COD输出量从每公斤饲料91g的COD翻了一番，达到194g。尽管HNSP系统中的COD产量较高，但与LNSP系统相比，生物滤池上的COD负载要低得多。对于HNSP和LNSP，生物滤池负载中的COD /氮（COD / N）比分别为1.7+或-0.2和2.2+或-0.2 g COD / gN。饮食中碳水化合物的组成从淀粉转移到NSPs，粪便COD的生物降解能力从66.3％降低到43.7％（P <0.001）。纤维分析表明，HNSP粪便中大约40％的COD来自纤维素和半纤维素。通过将粪便COD用作反硝化过程中的内部碳源，可以利用HNSP饮食中增加的COD产量。从理论上讲，HNSP系统废物流中的COD / N比值为7.2时，完全脱氮是可能的。但是，尚不清楚HNSP粪便的低COD生物利用度是否可能是限制因素。这项研究表明，可通过改变饮食中碳水化合物的含量来控制生物滤池负荷和系统产量中的COD / N比。尽管日粮中NSP含量的增加增加了COD的产生，但它也增加了COD的回收率，降低了生物滤池中COD的负荷，并产生了足够的碳用于内部来源的反硝化。

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