Page 61 - 《水产学报》2025年第8期

石今朝，等 水产学报, 2025, 49(8): 089405

Chronic potential of low concentration aqueous deltamethrin to
intestinal histology and gut microbiota in Eriocheir sinensis

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SHI Jinzhao , TAO Xianji 1,2,3* , JIANG Xiaodong , CHENG Yongxu 1,2,3 , WU Xugan 1,2,3*
1. Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources,
Shanghai Ocean University, Shanghai 201306, China;
2. Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai 201306, China;
3. National Demonstration Center for Experimental Fisheries Science Education,
Shanghai Ocean University, Shanghai 201306, China

Abstract: Deltamethrin (DM) has been used in aquaculture as pests defender, parasites remover, salmon delouser, ponds
cleanser, and so on. The low-dose DM, less than safety concentration (SC) in surface water is ubiquitous and lasts for the whole
agricultural period because of frequent use. To understand the chronic stress of deltamethrin below SC on Eriocheir sinensis
intestine, this research acquired the SC as 0.190 μg/L calculated from the data of acute experiments with Turubell formula, and
then investigated on juvenile E. sinensis exposed to 0, 0.024, 0.095 and 0.380 μg/L DM for 30 days. Two samples were taken
from each level at 0 d and 30 d, and examined intestinal histological structures on the slices stained with H.E. and also ana-
lyzed gut microbiota based on the sequence (after DNA extraction, amplification and library construction). The main results
showed that ① Histological examination showed DM damaged the intestine histological structure of juvenile E. sinensis，
whose adverse effects increased with the increment of DM concentration. Exposed to DM of 0.380 μg/L, the mucosal epithelial
cells were collapsed, in which the mucous layer separated from the submucous layer; the villi were destructed, in which the
cuticle layer separated from the mucous layer, even intestinal glands messed up. Exposed to DM of 0.095 μg/L, some part of
the mucous layers were collapsed, mucous layer cells were partly degraded, and intestinal glands were partly messed up.
Exposed to both 0.024 and 0 μg/L DM, there were no observable effects. ② The gut microbiota equilibrium was broken in the
intestine of E. sinensis exposed to DM of chronic concentration. Ace and Chao1 indexes decreased with the increment of DM
concentration, which indicated DM decreased the microbial diversity in intestine ecology. ③ In phylum-level analysis, the
beneficial bacteria was decreased and pathogenic bacteria was increased in the intestinal microbiota of juvenile E. sinensis
exposed to DM below the SC. DM increased the relative abundances of Proteobacteria in 0.380 μg/L treatment (P<0.01), and
Bacteroidota in 0.095 μg/L treatment (P<0.05), decreased the relative abundances of Tenericutes in 0.095 and 0.380 μg/L treat-
ments (P<0.05), and Firmicutes in 0.024, 0.095 and 0.380 μg/L treatments (P<0.05). ④ In genus-level analysis, DM increased
the relative abundances of Acinetobacter, Bacteroides, and Wolbachia in all treatments (P<0.05), even resulted in some patho-
genic bacteria of Pseudomonas, Shewanella, Chryseobacterium, and Flavobacterium in 0.380 μg/L treatment. In summary, DM
of SC caused E. sinensis intestine in chronic stress, which damaged the intestine histological structure, broke the equilibrium of
beneficial microbiota, and increased the relative abundances of pathogenic bacteria. The calculated safety concentration is not
truly safe, which indicates that real DM safety concentration for juvenile E. sinensis needs more trials in aquaculture.
Key words: Eriocheir sinensis; deltamethrin; intestinal health; safety concentration

Corresponding authors: TAO Xianji. E-mail: xjtao@shou.edu.cn;
WU Xugan. E-mail: xgwu@shou.edu.cn

Funding projects: Chinese Agriculture Research System (CARS-48); Ministry of Foreign Affairs Cooperation Funds Projects
in Asia (125A0607); the “JBGS” Project of Seed Industry Revitalization in Jiangsu Province (JBGS[2021]127); Shanghai
Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture Animals (2021-KJ-02-12)

中国水产学会主办 sponsored by China Society of Fisheries https://www.china-fishery.cn
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