Abstract:In response to growing worldwide market demand, intensive shrimp farming, based on high feed, has developed over the past decade. The nitrogenous compounds mainly generated by animal excretion can cause deterioration of water quality and produce chronic or even acute toxicity to aquatic animals. As prevention, theoretical safety levels have been estimated from acute toxicity tests and they are traditionally used to prevent toxic effects on biota. However, are those concentrations of nitrogenous compounds reall… Show more
“…For example, in the tanks with Penaeus vannamei, which contained up to 10 individuals of 10.7 g average weight, receiving 6.2 g of food per day, it was observed pH decrease if compared with the fasting treatment water completely clear (in the absence of food and almost also of wastes), where pH was significantly more alkaline (8.06), although within the normal range for cultivation. Nitrite reached 0.56 mg L -1 N-NO2in the mixed fasting treatment, but this concentration is much lower than what considered unsafe for the cultivation of another species of penaeid, F. paulensis, of 2.55 mg L -1 NO2 - (Wasielesky et al, 2017). However, the fact that this treatment lasted much less time (38 days to the harvest of the last tank) than the other five treatments (60 days), evidently also affected this comparison.…”
To compare the zootechnical performance of the Brazilian native shrimp Penaeus schmitti and the exotic shrimp Penaeus vannamei, juveniles were grown under controlled conditions. Both species were simultaneously cultivated (monoculture) in separate 70 L plastic tanks at two different densities: 30 and 50 ind m-2. Also, in the other two treatments, both species were cultivated together (mixed), with and without feeding, at 30 ind m-2. During the experiment, P. vannamei generally showed a greater interest in food and voracity than P. schmitti. At harvest, for both stocking densities of monoculture treatments, the mean growth rate observed for P. vannamei was 1.0 g week-1, while P. schmitti achieved only 0.1 g week-1. The mean final weight was 10.4 ± 2.0 g; 10.7 ± 2.1 g for P. vannamei and 2.8 ± 0.3 g; 3.2 ± 0.3 g for P. schmitti, for respective densities of 50 and 30 ind m-2. In the mixed treatment with feeding, while P. vannamei reached 11.9 ± 1.4 g, P. schmitti reached only 2.6 ± 0.4 g in the same tank. The observed differences were 3.7 and 3.4 higher in favor of P. vannamei in the monoculture treatment, and up 4.5 times higher in the mixed treatment. Under strict fasting conditions, both species practiced predation/cannibalism among themselves. The results reflected the zootechnical advantages of P. vannamei, but also corroborated the negative effect that high densities and lack of natural food can exert over native species. The potential for P. schmitti cultivation and the possible impact of the escape of P. vannamei into the natural environment is discussed.
“…For example, in the tanks with Penaeus vannamei, which contained up to 10 individuals of 10.7 g average weight, receiving 6.2 g of food per day, it was observed pH decrease if compared with the fasting treatment water completely clear (in the absence of food and almost also of wastes), where pH was significantly more alkaline (8.06), although within the normal range for cultivation. Nitrite reached 0.56 mg L -1 N-NO2in the mixed fasting treatment, but this concentration is much lower than what considered unsafe for the cultivation of another species of penaeid, F. paulensis, of 2.55 mg L -1 NO2 - (Wasielesky et al, 2017). However, the fact that this treatment lasted much less time (38 days to the harvest of the last tank) than the other five treatments (60 days), evidently also affected this comparison.…”
To compare the zootechnical performance of the Brazilian native shrimp Penaeus schmitti and the exotic shrimp Penaeus vannamei, juveniles were grown under controlled conditions. Both species were simultaneously cultivated (monoculture) in separate 70 L plastic tanks at two different densities: 30 and 50 ind m-2. Also, in the other two treatments, both species were cultivated together (mixed), with and without feeding, at 30 ind m-2. During the experiment, P. vannamei generally showed a greater interest in food and voracity than P. schmitti. At harvest, for both stocking densities of monoculture treatments, the mean growth rate observed for P. vannamei was 1.0 g week-1, while P. schmitti achieved only 0.1 g week-1. The mean final weight was 10.4 ± 2.0 g; 10.7 ± 2.1 g for P. vannamei and 2.8 ± 0.3 g; 3.2 ± 0.3 g for P. schmitti, for respective densities of 50 and 30 ind m-2. In the mixed treatment with feeding, while P. vannamei reached 11.9 ± 1.4 g, P. schmitti reached only 2.6 ± 0.4 g in the same tank. The observed differences were 3.7 and 3.4 higher in favor of P. vannamei in the monoculture treatment, and up 4.5 times higher in the mixed treatment. Under strict fasting conditions, both species practiced predation/cannibalism among themselves. The results reflected the zootechnical advantages of P. vannamei, but also corroborated the negative effect that high densities and lack of natural food can exert over native species. The potential for P. schmitti cultivation and the possible impact of the escape of P. vannamei into the natural environment is discussed.
“…Through the improvement of aquaculture techniques, cultivation conditions have intensified by increasing the production of this crustacean. However, one of the limiting factors for their production is the generation and accumulation of nitrogenous residues, mainly ammonia, originated from animal excretion, degradation of food residues and decomposition of organic debris in culture systems (Jia et al, 2015;Romano & Zeng, 2013;Wasielesky, Poersch, Martins, & Miranda-Filho, 2017).…”
Section: Introductionmentioning
confidence: 99%
“…High concentrations of ammonia tend to accumulate in body fluids of aquatic organisms, including shrimp (Liang et al, 2016), causing sublethal or lethal toxic effects. Among these, osmoregulatory disorders (Romano & Zeng, 2013), increased oxygen consumption (Barbieri, 2010), decreased growth rates and increased mortality (Campos, Furtado, D'incao, Poersch, & Wasielesky, 2015;Wasielesky et al, 2017), Krebs cycle suppression and decoupling of oxidative phosphorylation (Ding et al, 2017), changes and histological lesions (Dutra et al, 2017), decreased antioxidant capacity and oxidative stress (Jia et al, 2015) have been reported.…”
This study investigated the effects of the use of the inclusion of açaí on the diet of shrimp Litopenaeus vannamei on antioxidant and histopathological responses after exposure to ammonia. The shrimps were fed two experimental diets: control and with 10% of açaí inclusion (W/W), for 35 days. Afterwards, the organisms were exposed at four concentrations of ammonia (0.01‐control; 0.26; 0.48 and 0.91 mg NH3‐N L−1) for 96 hr. The total antioxidant capacity (ACAP) of the gills decreased significantly in both diets when exposed to ammonia, whereas in the muscle, the açaí promoted an increase in ACAP. Concomitantly, lipid peroxidation levels increased in the gills and decreased in muscle. After exposure to ammonia, glutathione‐S‐transferase activity increased in hepatopancreas in shrimps fed with açaí facilitating the detoxification of lipid peroxidation by‐products, and the concentration of protein sulfhydryl groups decreased in the gills and muscle of the shrimp of the control diet, evidencing protein damage, an unobserved response in shrimps that received the açaí diet. Histopathological changes decreased in açaí‐fed shrimps about the control diet after exposure to ammonia. It is concluded that açaí mitigated ammonia‐induced histopathological changes, improved the antioxidant defence system (gills and muscle) and attenuated the lipid damage in the muscle.
“…As a result, nitrite causes a decrease in the oxygen affinity of the shrimp hemolymph, eliminating its normal oxygen carrying capacity, and eventually resulting in asphyxiation (Jiann-Chu and . Indeed, it has been reported that nitrite has serious deleterious effects on shrimp growth (Wasielesky et al, 2017), immunity (Tseng and Chen, 2004), and survival (Wasielesky et al, 2017;Valencia-Castaneda et al, 2018. Therefore, low aquatic nitrite concentrations must be maintained for successful shrimp farming.…”
Nitrite is a major environmental toxin in aquaculture systems that disrupts multiple physiological functions in aquatic animals. Although nitrite tolerance in shrimp is closely related to successful industrial production, few genetic studies of this trait are available. In this study, we constructed a high-density genetic map of Litopenaeus vannamei with 17,242 single nucleotide polymorphism markers spanning 6,828.06 centimorgans (cM), with an average distance of 0.4 cM between adjacent markers on 44 linkage groups (LGs). Using this genetic map, we identified two markers associated with nitrite tolerance. We then sequenced the transcriptomes of the most nitrite-tolerant and nitritesensitive individuals from each of four genetically distinct L. vannamei families (LV-I-4). We found 2,002, 1,983, 1,954, and 1,867 differentially expressed genes in families LV-1, LV-2, LV-3, and LV-4, respectively. By integrating QTL and transcriptomics analyses, we identified a candidate gene associated with nitrite tolerance. This gene was annotated as solute carrier family 26 member 6 (SLC26A6). RNA interference (RNAi) analysis demonstrated that SLC26A6 was critical for nitrite tolerance in L. vannamei. The present study increases our understanding of the molecular mechanisms underlying nitrite tolerance in shrimp and provides a basis for molecular-marker-assisted shrimp breeding.
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