Effects of chronic high stocking density on liver proteome of rainbow trout (Oncorhynchus mykiss)

Abstract

The main aim of the present study was to assess the effects of chronic high stocking density on liver proteome of rainbow trout. Rainbow trout juveniles (42.6 ± 2.3 g average body weight) were randomly distributed into six tanks at two stocking densities (low stocking density (LD) = 20 kg m and high stocking density (HD) = 80 kg m). Both treatments were performed in triplicate tanks for a period of 60 days. High stocking density caused a reduction in the growth performance compared with LD fish. Lysozyme activity increased with stocking density, while serum complement activity presented the opposite pattern. Serum cortisol and total protein levels did not show significant differences (P > 0.05) between experimental groups. The fish reared at high stocking density showed significantly lower osmolality and globulin values but higher albumin level. The HD group had significantly higher activities of catalase, glutathione peroxidase and superoxide dismutase, and malondialdehyde content in the liver when compared to the LD group. Comparative proteomics was used to determine the proteomic responses in livers of rainbow trout reared at high stocking density for 60 days. Out of nine protein spots showing altered abundance (>1.5-folds, P < 0.05), eight spots were successfully identified. Two proteins including apolipoprotein A-I-2 precursor and mitochondrial stress-70 protein were found to increase in HD group. The spots found to decrease in the HD group were identified as follows: 2-peptidylprolyl isomerase A, two isoforms of glyceraldehydes-3-phosphate dehydrogenase, an unnamed protein product similar to fructose-bisphosphate aldolase, 78 kDa glucose-regulated protein, and serum albumin 1 protein.

Protein changes as robust signatures of fish chronic stress: a proteomics approach to fish welfare research

“…Cortisol is the most commonly used physiological indicator of the primary response to stress [21]. However, it has been shown that this corticosteroid is not a reliable biomarker of long-term stress exposure [27,[35][36][37]. In this study, Gilthead seabream that endured high stocking densities over 54 days showed a possible reconfiguration of the cortisol response.…”

Interactive effects of dietary Nano selenium and vitamin E on growth, haematology, innate immune responses, antioxidant status and muscle composition of rainbow trout under high rearing density

“…The results of this study also demonstrated that high rearing density without dietary supplementation (Control group) produced a chronic stressful situation. The stress caused by high‐density activates metabolic changes (activation of the catabolic pathways and mobilization of energy stores) to cope with the higher energy requirements (Lupatsch, Santos, Schrama, & Verreth, ; Suárez et al, ; Vijayan et al, ) therefore accelerates the metabolic rate of fish (Barton & Iwama, ) and suppresses fish growth (Naderi et al, ; Suárez et al, ; Vijayan et al, ).…”

“…Thus, rearing density is an important topic for the productivity and profitability of rainbow trout farms. We previously found that chronic high rearing density (80 kg/m 3 ) can negatively affect the growth performance, humoral immune responses and liver antioxidant status of rainbow trout (Naderi, Keyvanshokooh, Salati, & Ghaedi, ). High rearing density can produce undesired side‐effects and activate stress response (Wendelaar Bonga, ).…”

Protein changes as robust signatures of fish chronic stress: a proteomics approach in fish welfare research

“…Cortisol has been the most commonly used physiological indicator of the primary response to stress (21). However, there is a shred of evidence indicating that this corticosteroid is not a reliable biomarker of long-term stress exposure (27,(35)(36)(37). In this study, Gilthead seabream exposed to high stocking densities during 54 days showed a possible reconfiguration of the cortisol response.…”