Comparison of lipid metabolism between broodstock and hybrid offspring in the hepatopancreas of juvenile shrimp (Macrobrachium nipponense): Response to chronic ammonia stress

Abstract

Ammonia nitrogen is a major pollutant that causes great physiological harm to crustaceans in culture. In this study, we conducted a 28 day chronic ammonia nitrogen stress experiment with broodstock populations (Dianshan, DS) and hybrid offspring populations (DS ♀ × CD (Changjiang ♂ × Dongting ♀), SCD) exposed to 0, 1 and 10 mg/L of ammonia concentrations. A 28 day feeding trial and chronic ammonia nitrogen stress were used to investigate the effects on the growth performance, histological structure and lipid metabolism of juvenile shrimp, Macrobrachium nipponense. Our results indicated that survival rates in the SCD groups were significantly higher than those in the DS groups, whereas weight and length gain rates were not significantly different between the groups (p > 0.05). Histological structure results showed that the number of vacuoles in the DS group was significantly higher than that in the SCD group and hepatopancreas cell structures were disrupted in the ammonia treatment groups. The results of oil red staining showed that the number of lipid droplets increased significantly with the increase in ammonia concentration. As the ammonia concentration increased, fatty acid contents, lipid enzyme activities and lipid metabolism‐related gene expression all tended to rise. In conclusion, ammonia nitrogen exposure caused damage to the hepatopancreas structure of juvenile shrimp and disturbed the lipid metabolism of the hepatopancreas. In addition, the SCD population had stronger stress resistance than the DS population when subjected to the same concentration of ammonia nitrogen stress.

Differential Toxicity Responses between Hepatopancreas and Gills in Litopenaeus vannamei under Chronic Ammonia-N Exposure

“…Compared to the control groups, a common feature in the hepatopancreas was moderate-to-high vacuolation in R cells. Similar results have been found with Marsupenaeus japonicus [40] and M. nipponense [38]. This suggests that ammonia-N caused damage to the hepatopancreas structure, leading to a reduction in R cells, and then secretion and exretion of toxic substances through B cells, resulting in an increase in B cells.…”

“…R cells have many small lipid-filled vacuoles for the synthesis of lipoproteins and their export to other organs, heavy metal detoxification, and uric acid excretion. B cells are regarded as an important lipid reserve in tissues because of their functions of producing, secreting, and recycling fat emulsifiers [38]. In addition, they take charge of the accumulation and transport nutrients, which are also sensitive to toxic substances and other stresses [39].…”