Increased stocking density causes changes in expression of selected stress- and immune-related genes, humoral innate immune parameters and stress responses of XXXX ( @entity5660 ).

@entity14555 @entity5660 @entity25073 @entity1678 @entity70024 @entity701 @entity880
UNASSIGNED: The present study investigated the effects of various stocking densities on the health status (stress and immune responses) of @entity5660 ( @entity5660 ). Juvenile @entity5660 were acclimated, placed in circular tanks under stocking densities of 10, 40 and 80  kg  m(-3) and reared for 30 days. The relative expression of genes involved in stress and immunity such as @entity70024 , LyzII, TNF-1a, @entity14555 , @entity25073 and IFN-y1 in the head kidney was determined. Serum @entity701 , ACTH, total antioxidant capacity, osmolality and @entity880 were measured after 30 days of culture at different stocking densities (D1:10  kg  m(-3), D2: 40  kg  m(-3) and D3: 80  kg  m(-3)) as indices of stress responses. In addition, the effects of stocking densities on serum complement, bactericidal activity, agglutinating antibody titers, serum IgM, anti-protease activity, serum total protein and alkaline phosphatase of the fish were measured. @entity70024 gene expression was significantly density-dependent upregulated in D2 and D3 densities compared to D1 (P  <  0.05). Also, there was significant downregulation in expression of LyzII, TNF-1a, @entity14555 , @entity25073 and IFN-y1 in fish reared at density of either D2 or D3 (P  <  0.05). In terms of stress responses, serum ACTH, @entity701 and @entity880 level showed significant density-dependent increase (P  <  0.05) while serum osmolality and total antioxidant capacity showed significant decline (P  <  0.05) in fish reared at higher densities (D2 and D3) compared to fish reared at lower density (D1) (P  <  0.05). Concordant with the expression of the immune-related genes, the serum complement and bactericidal activity as well as specific antibody titer against @entity1678 , IgM and anti-protease activity decreased along with elevation of stocking density from D1 to D3 (P  <  0.05). However, different stocking densities had no significant effect on serum total protein level and alkaline phosphatase activity. These results suggested that elevation of stocking densities and crowding resulted in the increase in @entity70024 gene expression and the levels of selected stress responses in the serum. However, there was down-regulation of immune genes expression and decreased innate immune responses in the fish. The mRNA expression of the genes and immune parameters that were measured in this study could be helpful in monitoring the health status and welfare of the fish in aquaculture systems particularly in relation to increased stocking densities.
