Abstract
In the practical farming of Litopenaeus vannamei, the intensive culture system and environmental pollution usually results in a high concentration of ammonia, which usually brings large detrimental effects to shrimp, such as increasing the susceptibility to pathogens, reducing growth, decreasing osmoregulatory capacity, increasing the molting frequency, and even causing high mortality. However, little information is available on the molecular mechanisms of the detrimental effects of ammonia stress in shrimp. In this study, we performed comparative transcriptome analysis between ammonia-challenged and control groups from the same family of L. vannamei to identify the key genes and pathways response to ammonia stress. The comparative transcriptome analysis identified 136 significantly differentially expressed genes that have high homologies with the known proteins in aquatic species, among which 94 genes are reported potentially related to immune function, and the rest of the genes are involved in apoptosis, growth, molting, and osmoregulation. Fourteen GO terms and 6 KEGG pathways were identified to be significantly changed by ammonia stress. In these GO terms, 13 genes have been studied in aquatic species, and 11 of them were reported potentially involved in immune defense and two genes were related to molting. In the significantly changed KEGG pathways, all the 7 significantly changed genes have been reported in shrimp, and four of them were potentially involved in immune defense and the other three were related to molting, defending toxicity, and osmoregulation, respectively. In addition, majority of the significantly changed genes involved in nitrogen metabolisms that play an important role in reducing ammonia toxicity failed to perform the protection function. The present results have supplied molecular level support for the previous founding of the detrimental effects of ammonia stress in shrimp, which is a prerequisite for better understanding the molecular mechanism of the immunosuppression from ammonia stress.
Highlights
The Pacific white shrimp, Litopenaeus vannamei, is one of the most important farmed penaeid shrimp species in the world, which currently provides about 52% of the total penaeid shrimp production in the world [1, 2]
The present study represents the first analysis for the identification of key genes and metabolic pathways response to ammonia stress at whole transcriptome level in shrimp
Our results revealed a total of 136 significantly differentially expressed genes that have strong homologies with known proteins in aquatic species, among which 94 genes were reported potentially related to immune function
Summary
The Pacific white shrimp, Litopenaeus vannamei, is one of the most important farmed penaeid shrimp species in the world, which currently provides about 52% of the total penaeid shrimp production in the world [1, 2]. In order to pursue more production value, semi-intensive and intensive culture systems are usually used for L. vannamei culture in many countries These culture behaviors often result in degradation of the culture water from waste products of the shrimps and uneaten food. Combining with the variable and deteriorated aquaculture environments, the toxicity from the degraded culture water factors is playing an important role in the high mortality of shrimp, which has significantly affected the yield and quality of L. vannamei [3,4,5,6]. The frequent outbreak of high mortality in the shrimp farms might be related to the enhanced toxicity of the ammonia from other multiple factors (such as higher temperature and low salinity by frequent rains in summer)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
