Real crabs (Brachyura) come from various environments such as land, fresh water, estuaries, mangroves and marine habitats, and are a very successful group of crustaceans. Their victory is closely related to their life cycle, especially their reproductive strategies. These strategies are crucial for the survival of this species and play an important role in the evolution and development of crabs. Mastering these reproductive systems and strategies is key to understanding crab phylogenetics and biology.
A team of Shantou University has made a large-scale advancement of the complex reproductive process of mud crabs (Scylla paramamosain). Leaded by Professor MA and joined by Professor Dahe Wang, Yang Yu, Weifeng Gao, Zifei Xiang, Zilin Zhao, Zilin Zhao, Hanafiah Fazhan, Khor Waiho and Mhd Ikhwanuddin, the team has combined their expertise. Form a final dispersion. Their findings featured in the aquaculture report, providing key insights into enhancing crab breeding methods.
In this pioneering study, a total of 60 crabs were carefully selected near the adult pubertal females, with careful selection near the adolescent Moorian females. The crabs are from Guangdong Province, China and are kept alone at Shantou University, where they are paired to mate in a controlled environment. This setup is essential for obtaining precise data while following ethical animal treatment standards.
The research team used a series of detailed and mild examination methods to study crab tissue. These tissues are treated with special solutions, stored, and then prepared for microscopic examination. The process allows researchers to closely examine the cellular structures in the crab’s reproductive organs.
In addition, the team also used advanced digital scanning technology to capture highly detailed images of the crab’s reproductive organs at all stages of development. This state-of-the-art scan allows for depth viewing in different levels of amplification.
To delve into the structural aspect, tiny tissue samples were carefully crafted for electron microscopy, which allowed the observation of tiny details. These samples were treated, dehydrated and embedded in resin medium and then sliced for detailed inspection. This approach provides profound insights into the structure and changes of sperm and reproductive organs. In addition, the surface of the sperm surface was prepared using a scanning electron microscope, allowing researchers to view the sperm in incredible details.
The collected data was analyzed in an organized manner using various software tools to ensure statistical accuracy and reliability. The research team used statistical analytics to compare the data to ensure that the results were significant and reliable.
Professor Hongyu MA, the principal investigator of the study, shared the main findings: “After mating, sperm and sperm mass show significant changes in the semen socket. This includes rupture of the sperm wall, the formation of large amounts of sperm mass, and sperm in multiple ovulation events. “Our study revealed dynamic transitions in sperm throughout the reproductive cycle of mud crabs, including sperm creation, transit and dispersion phases. In addition, we observed the keys of sperm in its preparation of fertilization Changes, such as the expansion of protective caps, the accumulation of specific substances, and the reduction of chromatin density in the nucleus. These insights greatly contribute to our understanding of the mud crab reproductive process”.
This study represents an important step forward in aquaculture, especially for species such as mud crabs that are economically and ecologically important. The insights of Shantou University team not only enhance our scientific understanding of crab reproductive biology; they also pave the way for advances in breeding practices and are crucial to maintaining and enhancing mud crab populations in aquaculture.
Journal Reference
Dahe Wang, Yang Yu, Weifeng Gao, Zifei Xiang, Zilin Zhao, Hanafiah Fazhan, Khor Waiho, Mhd Ikhwanuddin, Hongyu MA. “Dynamic changes in sperm during mud crab reproduction (Scylla paramamosain): From sperm formation, transport to dispersion”. Aquaculture Report, 2023. DOI: https://doi.org/10.1016/j.aqrep.2023.101866.
About the Author
Doctoral Master’s Degree He serves as Director of the Joint Research Center of the International Joint Research Center, focusing on important horse breeding varieties in the South China Sea region, and serves as Director of the Joint Shellfish Research Laboratory of Stu-UMT. He is the vice chairman of the China Mud Crab Industry Technology Innovation Platform, a member of the board of directors of the China Association of Young Scientists and Technicians, and is also the director of the Agricultural Science and Technology Professional Committee of the Guangdong Association of Young Scientists. He is also a visiting professor at the University of Mumbai, Malaysia and a visiting assistant at the California Institute of Technology. Professor MA is committed to solving key scientific and technical issues in marine biotechnology, breeding and aquaculture. Over the past decade, he has led a team (1) to map high-quality entire genomes on the chromosome layer of mud crab chromosome layer and reveal structural features. He identified the sex-specific SNP loci and mapped them on high-density genetic maps and further discovered the ZZ/ZW gender determination mechanism of mud crabs. He also elucidates the mechanisms of gender determination and differentiation through phenotype and NCRNA/gene perspectives. (2) He first developed genome selection technology based on liquid SNP chips and GWAS, and obtained new crab strains with fast growth rates and gentle aggressive behavior. He also first constructed specific hybridization techniques for crabs and cultivated two hybrid combinations with rapid growth rates and strong disease resistance. In addition, he created production and nursery techniques for indoor and outdoor artificial hatcheries and integrated multinutrient aquaculture techniques in pond and land-based terrestrial three-dimensional circular aquaculture techniques. The above achievements have strongly promoted the genetics of marine crustaceans and the development of aquaculture industries.
