Vitamins A₁and A₂in hepatic tissue and subcellular fractions in mink feeding on fish‐based diets and exposed to Aroclor 1242

Abstract

Two-month-old female mink were fed diets based on either Baltic herring (Clupea harengus membras) or freshwater smelt (Osmerus eperlanus) for 21 weeks. A portion of the smelt-fed mink were exposed orally to polychlorinated biphenyls (PCBs), Aroclor 1242 (1 mg/d). Retinol (vitamin A1), 3,4-didehydroretinol (vitamin A2), and their different fatty acyl esters were studied in hepatic tissue, microsomes, and cytosol by argentated reversed-phase high-performance liquid chromatography. As a result of Aroclor exposure, concentrations of the fatty acyl esters of vitamins A1 and A2 were about one-tenth and those of unesterified A2 one-fourth those of the control levels. In the fatty acyl esters, percentages of stearates (A1--18:0 and A2--18:0) increased at the expense of the other fatty acyl esters. The Aroclor exposure decreased concentrations of alcoholic and esterified forms of the A2 analog more than those of the corresponding A1 analog. In microsomes. Aroclor decreased the alcoholic and esterified vitamin analogs to the same extent (to 9-17%). In the cytosol compared to the control, the concentrations of the vitamin esters fell below 10%, but the alcoholic analogs remained at 30 to 40%. Despite equal dietary supply, in mink fed on Baltic herring, the hepatic levels of vitamin A, were only about one-third of the values found in the smelt-fed mink. The organochlorines also altered hepatic lipid composition and impaired breeding and kit growth. In the kits of the females fed on Baltic herring, blood hemoglobin was decreased.

Adipose tissue fatty acids suggest spatial and temporal dietary differences in great cormorants of the Baltic Sea area

“…The contribution of true freshwater prey to seabird diet may be studied by determining the molar ratio of the freshwater specific analogue of the fat-soluble vitamin A, i.e. A 2 (3,4-didehydroretinol) to the marine and brackish water analogue A 1 (retinol) (Käkelä et al, 2002a(Käkelä et al, , 2002b.…”

“…The contribution of true freshwater prey to seabird diet may be studied by determining the molar ratio of the freshwater specific analogue of the fat-soluble vitamin A, i.e. A 2 (3,4-didehydroretinol) to the marine and brackish water analogue A 1 (retinol) (Käkelä et al, 2002a(Käkelä et al, , 2002b. The procedure of sampling superficial adipose tissue on the knee of the birds by biopsy is not unduly invasive, and the sampling of subcutaneous adipose tissue has not been found to harm the birds (Iverson et al, 2007;Käkelä et al, 2010;Owen et al, 2010;Rocha et al, 2016).…”

Analysis of Hepatic Vitamins A1, A2, Their Fatty Acyl Esters, and Vitamin E for Biomonitoring Mammals Feeding on Freshwater Fish

“…Consequently, no commercial standards exist. We have found that the different forms of vitamin A-alcoholic versus esterified vitamins and A 1 versus A 2 analogs-are decreased to a different extent in mink exposed to PCBs [5,29]. Thus, in biomonitoring, detailed retinoid analysis of the tissues of freshwater fish-feeding mammals is needed.…”