College of Engineering and Technology, Tianjin Agricultural University, Tianjin, 300384, China.
College of Agronomy and Resource and Environment, Tianjin Agricultural University, Tianjin, 300384, China.
Ecotoxicol Environ Saf. 2020 Apr 1;192:110323. doi: 10.1016/j.ecoenv.2020.110323. Epub 2020 Feb 15.
The black soldier fly larvae (BSFL) have become a promising candidate for waste disposal and are an ideal feed source for animal nutrition. The uptake of heavy metals could influence the growth of BSFL, but the effects of heavy metal pressures on the gut microbiota of BSFL are largely uncharacterized. Here, we examine the influences of Cu and Cd on the growth and gut microbiota of BSFL as well as the distribution of accumulated heavy metals in the larvae and their feces. Exposure to Cu (from 100 to 800 mg/kg) and Cd (from 10 to 80 mg/kg) did not significantly inhibit the weight gain of BSFL. With elevated exposure doses, the contents of both Cu and Cd accumulated in the bodies and feces of BSFL were remarkably increased. In the BSFL feces, Cu mainly existed as residues, while Cd mainly existed as either water-soluble states (in the low-exposure groups) or residues (in the high-exposure groups). Cd was more readily enriched (47.1%-91.3%) than Cu (<30%) in vivo. More importantly, exposure to Cu and Cd remarkably altered the gut microbiota of BSFL, particularly in the phyla Proteobacteria, Firmicutes and Bacteroidetes. High exposure to the metals (i.e., Cu-800 and Cd-80 groups) substantially decreased the abundances of most of the dominant families, but significantly stimulated the enrichment of Brucellaceae, Enterobacteriaceae, Alcaligenaceae, Campylobacteraceae, and Enterococcaceae. Moreover, the bacterial diversity in the BSFL gut was significantly reduced following high exposure to the metals. These results may fill a gap in our knowledge of the effects of heavy metals on the intestinal microbiome of BSFL.
黑蝇幼虫（BSFL）已成为一种很有前途的废物处理候选者，也是动物营养的理想饲料来源。重金属的摄取可能会影响 BSFL 的生长，但重金属压力对 BSFL 肠道微生物群的影响在很大程度上尚未得到阐明。在这里，我们研究了 Cu 和 Cd 对 BSFL 生长和肠道微生物群的影响，以及重金属在幼虫及其粪便中的积累分布。暴露于 Cu（100-800mg/kg）和 Cd（10-80mg/kg）并没有显著抑制 BSFL 的体重增加。随着暴露剂量的增加，BSFL 体内和粪便中 Cu 和 Cd 的含量都显著增加。在 BSFL 粪便中，Cu 主要以残渣形式存在，而 Cd 主要以水溶性状态（在低暴露组中）或残渣形式（在高暴露组中）存在。Cd 的体内富集程度（47.1%-91.3%）高于 Cu（<30%）。更重要的是，Cu 和 Cd 的暴露显著改变了 BSFL 的肠道微生物群，特别是在变形菌门、厚壁菌门和拟杆菌门。金属的高暴露（即 Cu-800 和 Cd-80 组）显著降低了大多数优势科的丰度，但显著刺激了布鲁氏菌科、肠杆菌科、产碱杆菌科、弯曲杆菌科和肠球菌科的富集。此外，金属的高暴露显著降低了 BSFL 肠道中的细菌多样性。这些结果可能填补了我们对重金属对 BSFL 肠道微生物群影响的认识空白。
