Fish lipids factors affecting

OCPs paralyze the nerves of fish, which leads to disruptions in coordination and in the feeding reflex this in turn causes the fish to become emaciated. OCPs also disrupt the metabolizing of carbohydrates, proteins and lipids, and affect the reproductive cycle. All of these factors lead to many fish species weakening and dying out [6]. 

Most fish lipids contain FA. The main groups of FA can be saturated (SFA), monoun-saturated (MUFA), or polyunsaturated fatty acids (PUFA). The proportion of each FA group in the total lipid content from fish tissnes differs and depends primarily on the total lipid content (and hence lipid class composition) and can be affected by numerous biological factors. The total lipids of 25 Antarctic fish had on average 23.5, 37.7, 38.1% SFA, MUFA, and PUFA, respectively 253 temperate Australasian fish had on average... 

It was also found that the bio concentration potential is dependent on the age, sex, and species of the aquatic organisms. Many of these factors can be eliminated if the test is performed under identical conditions with the organisms of the same species, strain, sex, age, etc. or if the bio concentration factor is related to the lipid content of the organism (see Sect. 5.4). Some other important factors which may affect the bio concentration potential of chemicals in fish and other aquatic organisms are the toxic effects, bio availability, concentration of the chemicals in water, pH of the water, and especially the lipid content of the organisms. These factors will be discussed in more detail in the following sections. 

Because so many factors in addition to lipid composition can affect POP accumulation (discussed above), some researchers currently favor using whole body lipid and POP measurements to estimate risk of effects from POP exposure. This is essentially a lipid-adjusted CBR. A recent example of this approach is shown in detail by Meador et al.122. These authors used a number of studies from the literature on appropriate life stages of salmon to determine a lipid-adjusted threshold for effects for a wide range of endpoints after PCB exposure. This threshold number was then compared to levels of PCBs measured in wild juvenile salmon from a contaminated estuary, and many of the fish, on the lipid-adjusted basis, were determined to be at risk of effects from environmental exposure to PCBs. 

There are many interacting external (temperature, salinity, food availability) and internal factors, including species, sex, physiological status (gonad maturity, condition, age), that determine and affect the lipid content and composition of aquatic organisms. The (n-3) PUFA are essential for the normal development of embryos, larvae, and the nervous system, and for the proper functioning of the sense organs of marine and freshwater fish. 

In this paper we have discussed the factors that may affect the linear correlation between bioconcentration factors in fish and the 1-octanol/water partition coefficient. Since a lipid/water partitioning process is the principal process controlling the uptake of organic chemicals from the water, the same factors may also affect other QSARs in aquatic toxicology. 

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