Physiological Response of Asian Seabass Reared in Recirculating Aquaculture System under Different Stocking Densities (original) (raw)
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Fish Physiology and Biochemistry, 1999
High stocking density has been shown to produce a wide variety of effects on cultured fish populations, such as alterations in behavior and poor feed utilization, resulting in mortality and poor growth. High stocking density has also been reported to produce chronic stress and mobilization of energy sources in fish. There are few studies focusing on the effect of high stocking density on one of the most important marine fish species for Mediterranean aquaculture, gilthead seabream (Sparus aurata). Consequently, this study investigates the effect of high stocking density on juveniles of this species, focusing on effects of stocking density on growth, biochemical composition, immune status and hematology. The results of this study showed that high stocking density produced a chronic stress situation. Plasma cortisol levels increased up to 16.25 ng ml−1 in fish held at high stocking; this value was 4 fold that of fish held at low stocking; density (3.91 ng ml−1 ). As a consequenceof this stressful situation, there was both haemoconcentration and a decrease in alternative complement pathway (ACP), an important component of the immune system of fish (from 167.23 U ml−1 down to 146.37 U ml−1). Haematocrit, haemoglobin concentration and red blood cell count were significantly higher in fish held at high stocking density (43.87%, 10.76 9dl−1 and 3.36 ×106 mm−3, respectively) compared with those fish held at low stocking density (37.21%, 9.32 g/dlg−1 and 2.82 ×106 mm−3, respectively). In addition, high stocking density produced a decrease in hepatosomatic index (from 2.26 down to 2.04) and altered liver fatty acid composition. Oleic acid (18: 1n-9) decreased in liver total lipids of fish held at high stocking density and arachidonic acid (20: 4-n6) and n-3 high unsaturated fatty acids (n-3 HUFA) were reduced in liver polar lipids of those fish. These alterations reflect the effect of stocking density on lipid metabolism to help meet the increased energy demand.
Aquaculture Research , 2021
The Asian seabass Lates calcarifer mostly familiar as barramundi or seabass is a commercially important species. Asian seabass is naturally distributed in the Indo-west Pacific region and cultured from the Persian Gulf, Arabian Gulf, southeast Asia and Australia (FAO, 2020). Asian seabass is extremely carnivorous and can tolerate high salinity variations (Rimmer and Russell, 1998). High fecundity, captive breeding and rapid growth rate make this species a suitable candidate for aquaculture (de Jesus-Ayson & Ayson, 2014; Venkatachalam et al., 2018). The ability to tolerate crowding, high turbidity, varying salinities and temperature makes it a relatively hardy species (Boonyaratpalin, 1997; Yue
Brazilian Journal of Biology, 2024
Salinity is one of the most critical environmental parameters regarding fish physiology, modifying food intake and growth performance in many fish species. The present study has investigated the effects of different salinity levels on growth performance, feeding and survival of Asian seabass Lates calcarifer juveniles. Asian seabass juveniles were reared at 0 (T1), 5 (T2), 22 (T3), 36 (T4), and 42 (T5) ppt salinity. Approximately eight hundred thirty fish individuals with an average weight of 1.24±0.52 g were randomly distributed (166 fish/Tank) in 5 concrete tanks (each tank 30×6×4 ft, volume 19,122 L) for forty days. Juveniles were initially fed 42% crude protein-containing diets at a rate of 6% of their body weight per day. The results showed that salinity level had a significant effect on the weight gain (WG), average daily weight gain (ADWG), specific growth rate (SGR), feed conversion ratio (FCR), survival rate (SR), total biomass and health indices (p<0.05). The highest WG...
Consequences of High-Density Fish Culture.pdf
Alexandria Journal of Veterinary Sciences, 2017
An experiment was performed to appraise the biological performances and ingestive behavior of Nile tilapia (Oreochromis niloticus). In this respect, we examined three tilapia stocking densities; low density (LD, 100 fish m-3), medium density (MD, 200 fish m-3) and high density (HD, 400 fish m-3). Lately, Aeromonas hydrophila defied fish evaluated through calculating the cumulative mortality (%). Stocking density had no influence on survival rate while, the final weight markedly reduced with increased density. The ingestive behavior was higher in MD- reared fish than the LD-reared group, however, fish at HD had a higher feed intake (%) and feed conversion ratio. Fish at LD showed marked higher levels of total protein, albumin and globulin compared with those reared at HD. The plasma glucose and cortisol levels elevated in HD-raised fish contrast to LD and MD groups. LD-raised fish had more elevated RBCs and WBCs parallel to MD and HD. Similarly, lymphocytes, neutrophils, and monocytes (%) decreased with increasing density. Also, Serum antioxidant and lysozyme enzymes were considerably (P<0.05) higher in LD compared with MD and HD groups. Meanwhile, the Phagocytic index expressively increased in MD-raised fish compared with LD and HD groups. Finally, the HD -raised fish showed a markedly higher cumulative mortality (%) (χ2= 6.257**) than the MD and LD-raised fish. In light of these results, a high-density culture evolved chronic stress in Oreochromis niloticus and consequently altered the biological performances, ingestive behavior with a subsequent immune depressive effect as displayed by the cumulative mortality (%).
Gene, 2004
The worldwide decline of ocean fisheries stocks has provided a rapid growth in fish farming and the problems connected to animal welfare in aquaculture gained importance. In this context, we have looked for molecular markers among those genes whose expression could reasonably result modified by the different farming conditions. With this purpose, we have evaluated, in liver and brain of sea basses, grown for 3 months at different biomass density (&amp;amp;amp;amp;amp;amp;amp;lt;10, 80 and 100 kg/m3), the expression of those genes coding for proteins related to stress such as Heat Shock Proteins (HSPs), Metallothioneins (MTs) and Cytochrome P4501A (CYP4501A). In liver, the expression of MT and CYP4501A mRNA resulted induced in animals reared at 80 and 100 kg/m3. Inducible HSP70 appeared significantly over expressed only at the biomass of 100 kg/m3, while apparently, no induction was detectable for HSP90. In brain tissue instead, MT and HSP90 were induced already at 80 kg/m3; CYP4501A and HSP70 were influenced only at the higher population density of 100 kg/m3. In the last three decades, there has been an exponential increase in the interest concerning the description, classification and functional significance of stress-related proteins, in particular HSPs. These proteins represent precious biomarkers to evaluate the welfare conditions when they are still recoverable; detecting their mRNA by PCR is fast, easy and relatively inexpensive. Therefore, we propose this method as a good alternative to monitor fish welfare.