College of Fisheries, Guangdong Ocean University, Zhanjiang, China.
College of Fisheries and Life Science, Dalian Ocean University, Dalian, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Hubei Hongshan Laboratory, The Innovation Academy of Seed Design, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
Fish Shellfish Immunol. 2023 Aug;139:108924. doi: 10.1016/j.fsi.2023.108924. Epub 2023 Jul 4.
The effects of different stocking densities on Litopenaeus vannamei were investigated from the aspects of growth performance, immune response and transcriptome in this experiment. L. vannamei (initial body weight: 0.30 ± 0.02 g) were reared for 8 weeks at three stocking densities of 100 (LSD), 200 (MSD) and 300 (HSD) shrimp/m³, respectively. The results showed that the survival rate (SR), final body weight (FBW), weight gain rate (WGR), specific growth ratio (SGR) and protein efficiency ratio (PER) of L. vannamei significantly decreased, while the feed factor (FCR) significantly increased with the increase of stocking density. After Vibrio parahemolyticus infection, the SR of L. vannamei in the HSD group was significantly lower than that in the LSD and MSD groups. Increasing stocking density significantly increased the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lysozyme (LYS) while significantly decreased the activities of catalase (CAT) and phenol oxidase (PO) in the serum of L. vannamei. Similar changes of the gene expression as the activities of immune enzymes were found in the hemocytes. Pairwise comparison between the LSD, MSD and HSD group in the transcriptome analysis identified that there were 304, 1376 and 2083 differentially expressed genes (DEGs) in LSD vs MSD, MSD vs HSD and LSD vs HSD, respectively. Among them, most of the immune-related DEGs were down-regulated and metabolism-related DEGs were up-regulated with the increasing stocking density. In addition, KEGG enrichment pathway analysis revealed that several immune and metabolic related pathways including PI3K-Akt signaling pathway and AMPK signaling pathway were significantly enriched. Of these, the PI3K-Akt signaling pathway had the most DEGs and was also the most significantly enriched pathway. Furthermore, 16 DEGs (such as FOXO, PCK2 and CTSC, etc.) and partial immune enzyme activity (such as AST, CAT and PO, etc.) changes were closely correlated with the increase of stocking density when partial immune-related DEGs and immune-related enzymes were analyzed jointly. All these results indicated that changes in stocking density had a significant effect on the growth performance, immunity and transcriptome of L. vannamei.
本实验从生长性能、免疫反应和转录组水平研究了不同放养密度对凡纳滨对虾（Litopenaeus vannamei）的影响。凡纳滨对虾（初始体重：0.30±0.02g）分别在 100（LSD）、200（MSD）和 300（HSD）尾/m³三个放养密度下养殖 8 周。结果表明，随着放养密度的增加，凡纳滨对虾的存活率（SR）、终末体重（FBW）、体重增重率（WGR）、特定生长率（SGR）和蛋白质效率比（PER）显著降低，而饲料系数（FCR）显著增加。在感染副溶血弧菌后，HSD 组的 SR 显著低于 LSD 和 MSD 组。随着放养密度的增加，凡纳滨对虾血清中天冬氨酸转氨酶（AST）、丙氨酸转氨酶（ALT）和溶菌酶（LYS）的活性显著升高，而过氧化氢酶（CAT）和酚氧化酶（PO）的活性显著降低。在血细胞中也发现了与免疫酶活性相似的基因表达变化。在转录组分析中，LSD、MSD 和 HSD 组之间的两两比较表明，LSD 与 MSD 比较、MSD 与 HSD 比较和 LSD 与 HSD 比较分别有 304、1376 和 2083 个差异表达基因（DEGs）。其中，随着放养密度的增加，大多数免疫相关的 DEGs 下调，代谢相关的 DEGs 上调。此外，KEGG 富集通路分析显示，包括 PI3K-Akt 信号通路和 AMPK 信号通路在内的几条免疫和代谢相关通路显著富集。其中，PI3K-Akt 信号通路的 DEGs 最多，也是最显著富集的通路。此外，当部分免疫相关 DEGs 和免疫相关酶一起分析时，16 个 DEGs（如 FOXO、PCK2 和 CTSC 等）和部分免疫酶活性（如 AST、CAT 和 PO 等）的变化与放养密度的增加密切相关。所有这些结果表明，放养密度的变化对凡纳滨对虾的生长性能、免疫和转录组有显著影响。
