Toxicity, physiological, histopathological, handling, growth and antiparasitic effects of the sodium chloride (salt) in the freshwater fish aquaculture

Abstract

This paper provides the currently available knowledge in the literature regarding the use of sodium chloride (NaCl) in freshwater fish aquaculture and aquaria as related to toxicity, growth performance, transportation, physiology, immunity, histomorphology and antiparasitic treatment. This review assessed and discussed all of these factors, as well as the potential strategies available to be used in fish farming. Acute toxicity to NaCl varies widely among fish species (3.5-150.0 g L −1 ) depending on some environment factors, and many fish species are sensitive to concentrations near those required for their development, growth or for controlling and treating parasites. Acute exposure to NaCl may lead to mortality in different fish species, cause changes in feeding and swimming behaviour, as well as in growth performance and histomorphology of gills, while sublethal concentrations are less harmful. To reduce stress during transport of freshwater fish, concentrations of 1.0-10.0 g L −1 of NaCl in water have been tested for some fish species. Data have shown that survival, body growth of fish, food intake and stimulation of food conversion are affected by the NaCl concentration.Moreover, the effects of NaCl on the immune system, physiology and behaviour must also be considered. Sodium chloride may be a chemotherapeutic for controlling and treating ectoparasite diseases in farmed freshwater fish because of its effectiveness and low cost, but this compound may not be used in high or extreme toxic concentrations, since the maximum tolerance may be near the therapeutic doses. Therefore, this chemical product should be used with parsimony in fish farming. K E Y W O R D Saquaculture, blood, fish, growth, parasites, treatment | ACUTE TOXICITY OF NaCl IN FRESHWATER FISH SPECIESKnowledge on the tolerance limits of freshwater fish to NaCl is of ecological significance in assessing fish distribution and their impact on ecosystems, as well as for management practices in fish farms.The most common laboratory measure of NaCl tolerance is the concentration that is lethal to 50% of individuals (LC 50 ) over periods of 24-96 h. Such determinations are experimental and establish a causal link between the salinity and mortality. Some species of freshwater fish tolerate high concentrations of NaCl for longer periods when compared with other freshwater fish species (Table 1), and concentrations may be near the lethal concentration for the fish species. However, they lack consideration of other changes in the water quality that may occur with an increased salinity. Thus, it is necessary to know beforehand the mean lethal concentration (LC 50 ) for each species of fish as well as the environmental conditions for exposure to NaCl.How to cite this article: Tavares-Dias, M. (2022). Toxicity, physiological, histopathological, handling, growth and antiparasitic effects of the sodium chloride (salt) in the freshwater fish aquaculture.

Efficacy of chlorine, sodium chloride and trichlorfon baths against monogenean Dawestrema cycloancistrium parasite of pirarucu Arapaima gigas

“…The lethal concentration to kill 50% of individuals (LC 50 ) over 24 to 96 h is the most common laboratory measure of toxicity in fish and contributes to the determination of concentrations and exposure times for in vivo testing (Tavares‐Dias, 2021; Zucker, 1985). The LC 50–96 h values of sodium chloride and trichlorfon for juvenile pirarucu were 9.9 g/L and 9.73 mg/L, respectively.…”

“…Regarding sodium chloride, values close to LD 50–96 h (11.88 g/L) were found for the beta fish Betta splendens (Zuanon et al, 2009). The LD 50 values of sodium chloride can vary greatly depending on the exposure time, species, temperature, and other environmental conditions (Tavares‐Dias, 2021). For example, Araújo da Silva et al (2018) found that pirarucu larvae (183.1 ± 41.2 mg; 3.4 ± 0.3 cm) can be reared for 15 days in salinities of up to 4% (4 g/L) with increased fish survival and growth, indicating that A. gigas shows some tolerance to sodium chloride.…”

“…Efficacy was found in the sodium chloride baths. The mechanism of action of salt in monogeneans has not yet been elucidated (Treves‐Brown, 2000), but it may be similar to its effect in fish, which comprises alterations in osmotic and energetic balance (Tavares‐Dias, 2021). Regarding trichlorfon, there is a diversity of treatments that vary in exposure time and use of high or low doses.…”

“…Sodium chloride (NaCl) is a versatile product widely adopted in aquaculture worldwide to reduce osmotic stress in fish, reduce nitrite toxicity, and control various diseases. It stands out for its affordable value and ease of purchase and is a safe compound for use in fish that will be consumed by humans (Tavares‐Dias, 2021; Treves‐Brown, 2000; Woo, 2006). It can be adopted in pirarucu larviculture to increase the survival of Artemia nauplii during the feeding training period without compromising larval survival (Araújo Da Silva et al, 2018), and in rearing and fattening to reduce transport stress (Gomes et al, 2006).…”

Sodium chloride against Dawestrema cycloancistrium in juvenile Arapaima gigas

“…Some records concerning therapeutic and prophylactic treatments for pirarucu are available, including the use of chemicals applied in therapeutic baths for monogenoid control, i.e., formaldehyde (Andrade-Porto et al 2017) and herbal medicines, such as essential Mentha piperita (Malheiros et al 2016) and Piper aduncum (Corral et al 2018) oils and aqueous P. aduncum extracts (Queiroz et al 2020). In addition, sodium chloride (NaCl), a natural product widely employed in aquaculture activities, has been reported as a promising alternative concerning pirarucu growth and survival, due to its various bene ts and low costs (Silva et al 2019;Tavares-Dias, 2021).…”