Dietary Selenium Requirement of Fingerling Channel Catfish

Abstract

Two experiments were conducted in aquaria to determine the minimum dietary selenium requirement of fingerling channel catfish (Ictalurus punctatus). Casein-gelatin diets containing graded levels of supplemental selenium (as Na2SeO3) ranging from 0 to 15 mg/kg were fed to catfish for 15 weeks in experiment 1 to broadly define their selenium requirement and toxicity levels. Although growth of catfish was affected by dietary selenium level, significant differences in weight gain were not easily discernible due to variability among the groups of fish. Weight gain data generally indicated that the basal diet containing 0.06 mg Se/kg diet caused growth depression, and a supplemental selenium level of 15 mg/kg also caused a reduced growth response, which indicated selenium toxicity. Selenium concentrations in edible muscle tissue increased almost linearly with increasing dietary selenium levels. Liver and plasma selenium-dependent glutathione peroxidase (Se GSH-Px) activities indicated the selenium requirement of fingerling channel catfish was between 0.1 and 0.5 mg Se/kg diet. In experiment 2, casein-gelatin diets containing incremental levels of supplemental selenium were fed to catfish for 14 weeks to more precisely determine their minimum dietary selenium requirement. Growth data and liver and plasma Se GSH-Px activities indicated that the minimum selenium requirement of fingerling channel catfish fed adequate vitamin E was 0.25 mg Se/kg dry diet. Based on these data, it appears that selenium supplementation of commercial catfish feeds is warranted.

The effects of dietary selenium on growth performances, oxidative stress and tissue selenium concentration of gibel carp (Carassius auratus gibelio)

“…The positive relationships between GPx activities and tissue Se concentrations have been reported in rainbow trout (Hilton et al 1980;Ku¨c¸u¨kbay et al 2009), channel catfish (Gatlin & Wilson 1984), grouper (Lin & Shiau 2005) and African catfish (Abdel-Tawwaba et al 2007). This is in accordance with the present results of a linear regression relationship between hepatic GPx activity and hepatic Se concentration or whole body Se concentration in gibel carp.…”

“…Various forms of Se have different bioavailability (Wang & Lovell 1997) and this affects the Se requirement for fish. The forms of Se used in two earlier studies (Hilton et al 1980;Gatlin & Wilson 1984) were sodium selenite, whereas Lin & Shiau (2005) and Abdel-Tawwaba et al (2007) adopted organic Se as in this study. The waterbone Se concentration in the two earlier studies ranged from 0.4 to 2.5 lg Se L )1 , whereas Se concentration of the rearing water in the recent two studies was not detectable.…”

The effects of organic selenium on performance and oxidative level in rainbow trout (<i>Oncorhynchus mykiss</i>, Walbaum, 1792) fed a high-fat diet

“…Studies on Se requirements led to quantification of this element in a number of fish species, e.g., rainbow trout (Hilton et al, 1980), channel catfish (Gatlin and Wilson, 1984) and juvenile grouper (Lin and Shiau, 2005). An increase in the fat content of the diet may lead to a higher level of non-enzymatic antioxidants, thereby increase the Se requirement.…”

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“…Catfish fed Se from organic sources had better growth than those fed Se from inorganic sources at suboptimal levels but not at levels above the minimum dietary requirement 30 . Se deficiency is associated with decreased activities of Se-dependent antioxidant enzymes such as glutathione peroxidase (GPx) and thioredoxin reductase that have been linked to the occurrence, virulence, or disease progression of some viral infections 1,31 .…”