Trace elements and organochlorine pollutants in selected fish species from Lake Phewa, Nepal

The content of metals in fish fillet is an important criterion for food safety and nutritional benefits. Fish fillet is composed of both white and red muscles, but the standard method only detects metal content in white muscle. The true metal content in fish fillet can be underestimated due to this approach. So far, metal content in different types of muscle tissue of freshwater fish remains virtually unstudied. The aim of the present research was to study the metal content in red and white muscles of roach Rutilus rutilus, bream Abramis brama and pike Esox lucius that live in the Krasnoyarsk reservoir. Twenty metals were measured in the dry mass of red and white muscles of three fish species using inductively coupled plasma (ICP-OES) spectrometry. The contents of macronutrients such as K, Ca and Mg were higher in white muscle fibers and Na – in red fibers. Of the 16 metals regarded as trace elements, the highest contents in the muscles were noted for Fe (20.5-177.8 μg/g), Zn (26.7-79.0 μg/g), and Al (15.2- 67.2 μg/g), regardless of the fish species and type of tissue. Li (0.01-0.09 μg/g) and Cd (0.01-0.03 μg/g) had the lowest concentrations. Among trace elements, the contents of Cu and Fe were significantly higher in the dry biomass of red muscle compared with white muscle for the three fish species. The content of Zn was higher in the red muscle of bream and pike. Almost all other trace elements also tended to accumulate in higher concentrations in the red muscle. Differences between red and white muscles in the contents of trace elements such as Pb and Sr were species-specific. The distribution of metals between the two types of muscle fibers demonstrated by the freshwater species examined in this study was similar to the distribution of metals in marine fish, except the distribution of Sr. Thus, the greater capacity of the red muscle for accumulating most heavy metals confirmed in the present study may indicate a greater risk to health in eating this type of tissue

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The use of essential trace elements in the juvenile rearing of barramundi (Lates calcarifer

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/57/1956 ◽

2014 ◽

pp. 33-38

Author(s):

Milán Fehér ◽

Edina Baranyai ◽

Edina Simon ◽

Péter Juhász ◽

Éva Csorvasi ◽

...

Keyword(s):

Trace Elements ◽

Growth Performance ◽

Fish Species ◽

Optimal Growth ◽

Predatory Fish ◽

Combined Treatments ◽

Lates Calcarifer ◽

Diet Supplements ◽

Essential Trace Elements ◽

Dry Diet

Barramundi (Lates calcarifer L.) is a predatory fish species native in Southeast Asia and Australia. Based on the geothermal potentiality of Hungary the warm-water fish can be reared successfully. Zooplankton in the wild contains minerals in a higher concentration than the usually fed newly hatched Artemia nauplii, therefore essential trace elements, such as cobalt, zinc and manganese play an important role in the larviculture of barramundi. Cobalt is vital in trace amount for many living functions of vertebrates, however, lower number of papers are available considering the nutritional aspects. Nevertheless. improved growth performance was observed in cases of some fish species when diet was supplemented with CoCl2. Zinc and manganese are also vital for optimal growth and accordingly are investigated and applied diet supplements in aquaculture. The main aim of the recent study is to investigate the effects of cobalt, manganese and zinc on the growth performance and homogeneity of fish when a commercially available dry diet is supplemented with trace elements individually and in combined treatments. A total of 6 treatments were set in a randomized blocked design where the concentrations of the applied elements were 50 mg kg-1 for CoCl2, for ZnSO4 and for MnCl2 individually, as well as for CoCl2 along with ZnSO4 and for CoCl2 along with MnCl2 in combination. Although the production parameters of larval barramundi were positively affected by the addition of trace elements when the retention of minerals occurred through nourishment living organisms, statistically no differences were found between the treatments considering the growth performance of barramundi juveniles either when dry feed was supplemented with cobalt, manganese or zinc (p>0.05). While the use of cobalt and manganese in combined treatments produced a less uniform larvae in size and as a consequence of increased heterogeneity, survival was significantly reduced by the cannibalism, the sizes distribution of barramundi juveniles wasn’t affected by the dry diet supplementation of these elements.

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