Microscopical analysis of the hepatopancreas in whiteleg shrimp (PhD summary)

Microscopical analysis of the hepatopancreas in whiteleg shrimp (PhD summary)

The aquaculture of penaeid shrimp has grown from its experimental beginnings three decades ago into a major industry. Almost from the start, diseases and adverse environmental conditions were recognized as threats to the shrimp industry. Current methods to assess health and nutritional status in shrimp mainly rely on clinical examination followed by laboratory investigations and evaluation of growth performance. One of the key indicators of health in shrimp is the perigastric organ (formerly known as the hepatopancreas), making it one of the most useful to examine. Feeding regime affects the perigastric organ. Under starvation and refeeding conditions, beneficial lipid droplets are rapidly depleted and haemocytes (comparable to the white blood cells in mammals) are recruited to mitigate degenerative processes and inflammation occurring in the organ. Haemocyte infiltration in the intertubular spaces of the perigastric organ is also observed in instances of tissue damage (traumatic or due to infection), toxicity and environmental stress.

In current practice, histological analysis of the perigastric organ is based on qualitative features interpreted by pathologists. Pathologists’ quantification is generally time-consuming and poorly objective, with significant discrepancies in scoring results reported between observers. This has motivated the development of computer-assisted image analysis (CAIA) methods for producing unbiased, objective, reproduc-ible, and reliable data. The basic principle of automated image analysis for histology is the use of a series of mathematical algorithms to process images, enabling the segmentation of picture elements into regions of interest based on their colour, texture and/or context.

The main findings of this study can be considered as a starting base to implement image analysis in the shrimp histology labs for diagnosis purposes and to start collecting reference values of the developed morphological parameters to be used for screening health and nutritional status in crustaceans. The development of specific indices (inflammatory and nutritional) will be used in the future to collect reference values for monitoring health, assess the impact of different diets and feeding regimes, facilitate early diagnosis of diseases and study the pathophysiology of the perigastric organ.

 

References:

  • Cervellione, F., McGurk, C., Silva, P., Owen, MAG & Van den Broeck, W. (2016) Optimization of fixation methods for image analysis of the hepatopancreas in whiteleg shrimp, Penaeus vannamei (Boone). Journal of Fish Diseases, doi:10.1111/jfd.12531. 
  • Cervellione, F., McGurk, C., Berger Eriksen, T. & Van den Broeck, W. (2016) Use of computer-assisted image analysis for semi-quantitative histology of the hepatopancreas in whiteleg shrimp Penaeus vannamei (Boone). Journal of Fish Diseases, doi:10.1111/jfd.12599.
  • Cervellione, F., McGurk, C. & Van den Broeck, W. (2017) Effect of starvation and refeeding on the hepatopancreas of whiteleg shrimp Penaeus vannamei (Boone) using computer-assisted image analysis. Journal of Fish Diseases, doi:10.1111/jfd.12599.
  • Cervellione, F., McGurk, C. & Van den Broeck, W. (2017) “Perigastric organ”: a replacement name for the “hepatopancreas” of Decapoda. Journal of Crustacean Biology, doi: 10.1093/jcbiol/rux020.
  • Cervellione, F., McGurk, C. & Van den Broeck, W. (2017) Effect of starvation and refeeding on the ultrastrucutre of the perigastric organ (hepatopancreas) in whiteleg shrimp Litopenaeus vannamei (Boone, 1931) (Decapoda: Caridea: Penaeidae). Journal of Crustacean Biology, doi: 10.1093/jcbiol/rux085.