Al-Ashhab Ashraf, Alexander-Shani Rivka, Avrahami Yosef, Ehrlich Roberto, Strem Rosa Ines, Meshner Shiri, Shental Noam, Sharon Galit
Dead Sea and Arava Science Center, 8698000, Masada, Israel.
Ben Gurion University of the Negev, Eilat Campus, Beersheba, Israel.
Anim Microbiome. 2022 Jun 21;4(1):42. doi: 10.1186/s42523-022-00191-y.
The welfare of farmed fish is influenced by numerous environmental and management factors. Fish skin is an important site for immunity and a major route by which infections are acquired. The objective of this study was to characterize bacterial composition variability on skin of healthy, diseased, and recovered Gilthead Seabream (Sparus aurata) and Barramundi (Lates calcarifer). S. aurata, which are highly sensitive to gram-negative bacteria, were challenged with Vibrio harveyi. In addition, and to provide a wider range of infections, both fish species (S. aurata and L. calcarifer) were infected with gram-positive Streptococcus iniae, to compare the response of the highly sensitive L. calcarifer to that of the more resistant S. aurata. All experiments also compared microbial communities found on skin of fish reared in UV (a general practice used in aquaculture) and non-UV treated water tanks.
Skin swab samples were taken from different areas of the fish (lateral lines, abdomen and gills) prior to controlled infection, and 24, 48 and 72 h, 5 days, one week and one-month post-infection. Fish skin microbial communities were determined using Illumina iSeq100 16S rDNA for bacterial sequencing. The results showed that naturally present bacterial composition is similar on all sampled fish skin sites prior to infection, but the controlled infections (T 24 h post infection) altered the bacterial communities found on fish skin. Moreover, when the naturally occurring skin microbiota did not quickly recover, fish mortality was common following T (24 h post infection). We further confirmed the differences in bacterial communities found on skin and in the water of fish reared in non-UV and UV treated water under healthy and diseased conditions.
Our experimental findings shed light on the fish skin microbiota in relation to fish survival (in diseased and healthy conditions). The results can be harnessed to provide management tools for commercial fish farmers; predicting and preventing fish diseases can increase fish health, welfare, and enhance commercial fish yields.
养殖鱼类的健康受到众多环境和管理因素的影响。鱼皮是免疫的重要部位，也是感染的主要途径。本研究的目的是表征健康、患病和康复的金头鲷（Sparus aurata）和尖吻鲈（Lates calcarifer）皮肤细菌组成的变异性。对高度敏感的革兰氏阴性菌的金头鲷用哈维氏弧菌进行攻毒。此外，为了提供更广泛的感染情况，两种鱼类（金头鲷和尖吻鲈）均感染革兰氏阳性海豚链球菌，以比较高度敏感的尖吻鲈与抗性更强的金头鲷的反应。所有实验还比较了在紫外线（水产养殖中的常用做法）处理和未处理的水箱中饲养的鱼皮肤微生物群落。
在控制感染前，以及感染后24、48和72小时、5天、1周和1个月，从鱼的不同部位（侧线、腹部和鳃）采集皮肤拭子样本。使用Illumina iSeq100 16S rDNA对细菌进行测序，确定鱼皮肤微生物群落。结果表明，感染前所有采样的鱼皮肤部位天然存在的细菌组成相似，但控制感染（感染后24小时）改变了鱼皮肤上发现的细菌群落。此外，当天然存在的皮肤微生物群不能迅速恢复时，感染后（感染后24小时）鱼类死亡很常见。我们进一步证实了在健康和患病条件下，非紫外线和紫外线处理的水中饲养的鱼皮肤和水中发现的细菌群落的差异。
我们的实验结果揭示了与鱼类生存（患病和健康状况）相关的鱼皮肤微生物群。这些结果可用于为商业养鱼户提供管理工具；预测和预防鱼类疾病可提高鱼类健康、福利并提高商业鱼产量。
