Docosahexaenoic Fatty Acid Research Articles

N-3 Enrichment of Chicken Meat. 1. Use of Very Long-Chain Fatty Acids in Chicken Diets and Their Influence on Meat Quality: Fish Oil

We assessed the effect of a diet supplemented with fish oil (FO) on the performance, fatty acid (FA) composition, quality, and sensory traits of broiler meat. Diets enriched with 0, 2, or 4% FO plus tallow (T) up to 8% added fat (T1, T2, and T3, respectively) were given to the birds throughout a 38-d growth period. T3 was replaced by a mixture of FO, linseed oil (LO), and T (1, 3, and 4% respectively) for 1 wk (T4) or 2 wk (T5) before slaughter. Meat quality, taste, and FA profile were determined. Higher final weights were recorded for birds fed T3, although feed efficiency was not affected. Other performance or objective meat quality parameters did not show significant differences among treatments. High FO concentrations decreased the saturated and monoenoic FA contents in the thigh samples. The amount of polyunsaturated fatty acids (PUFA) increased when added to the diet (FO diets), mainly as long-chain n-3 FA [eicosapentaenoic fatty acid (EPA), docosapentaenoic fatty acid (DPA), and docosahexaenoic fatty acid (DHA)]. On the other hand, levels of total n-6 FA resulted in slight changes, mostly in linoleic acid (LA). By replacing the FO diet with the experimental mixture (T4, T5), the n-3 and n-6 FA contents increased, mainly in the form of linolenic acid and LA, respectively, only 1 wk later. After 1 wk of T4, the DHA levels in chicken decreased. Sensory panelists could not identify the meats from T4 and T5 as being different from the control diet (T1).

Fatty acids specifically related to the anisotropic properties of plasma membrane from rat urothelium

Four different luminal surfaces of rat urothelium differing in their fatty acid composition were prepared by dietary induction. In order to induce lipid changes, each of four groups of rat received a basal diet rich in one of the unsaturated n-3, n-6 or n-9 fatty acid families and a commercial (control) diet. The effects of the dietary regime on the fatty acid composition of luminal urothelial membranes and their relation to the mobility of fluorescent probes were studied. In comparison with the control diet membrane, all three fatty acid-rich diets induced a decrease of the percentage amount of saturated fatty acid while that of the unsaturated fatty acids was increased. Accordingly, all three diets increased the unsaturation index in comparison with the control diet. The anisotropy across each membrane fraction was assessed using the n-(9-anthroyloxy) fatty acid fluorescent probes 3-AS, 7-AS and 12-AS, which locate at different depths in the membrane. Two different anisotropy profiles were observed. One profile showed the highest anisotropy at the C7 depth, whereas the other exhibited a continuous decrease of the anisotropy from the surface to the center of the bilayer. The molecular properties (isomerization) of 18:2 n-9 fatty acid may account, at least in part, for the observed V-shaped profile (the ascending trend) of the membrane anisotropy values as a function of the respective 18:2 n-9 fatty acid contents. Nevertheless, the minimum value of the profile did not correspond to the minimum 18:2 n-9 fatty acid content, but rather to the higher amount of docosahexaenoic (22:6 n-3) fatty acid. Thus, a modulating role of the 22:6 n-3 fatty acid on the rigidifying effect of 18:2 n-9 fatty acid is suggested, possibly mediated by relationships between fatty acid composition, saturated and unsaturated chain lengths, and freedom of motion of the phospholipid acyl chains.

Incorporation of Docosahexaenoic Fatty Acid into the Lipids of a Cestode of Marine Elasmobranchs

Callibothrium verticillatum, a cestode from the spiral intestine of the dogfish, Mustelus canis, incorporated a characteristic polyunsaturated fatty acid of marine organisms (22:6 03) without conversion or degradation. The tapeworm was incubated in vitro with [14C] 22:6 w3. Its labeled lipids were fractionated and their radioactivities assayed by column and thin-layer radiochromatography nlethods. Triglyceride (50% of dpm collected) and unesterified fatty acids (28%) were the most radioactive fractions. Sterol ester, wax ester, diacylglyceryl ether, diglyceride, monoglyceride, cardiolipin, phosphatidylethanolamine, phosphatidylserine, and phosphatidylcholine also were radioactive. 22:6 ca3 and the other fatty acids of the tapeworm were collected by preparative gas-liquid radiochromatography from the total fatty acids, hydrogenated total fatty acids, triglyceride fatty acids, and unesterified fatty acids. Only 22:6 w3 was radioactive. Lipids were 25% of the dry weight of C. verticillatum. The major lipids were triglyceride (54 wt% of total) and phosphatidylcholine (25%). The polyunsaturated fatty acids of the neutral lipids were mostly eicosenoic (20:5 w3 was 25% of total), and of the polar lipids were docosenoic (22:6 w3 was 30%). The fatty acid composition of the tapeworm, the contents of the spiral intestine, and the fluids and tissues of the dogfish were strikingly similar. It is concluded that polyunsaturates may be passed intact from one trophic level to another in marine food chains, and that tapeworms can be used to monitor lipids in the food chains in which the hosts participate. Polyunsaturated C20 and C22 fatty acids are characteristic components of the storage and membrane lipids of most marine organisms; for example, planktonic unicellular algae (except blue-greens and the Chlorophyceae) (Kates and Volcani, 1966; Ackman et al., 1968; Chuecas and Riley, 1969; Holz, 1969; Lee and Loeblich, 1971), benthic multicellular algae (except Chlorophyceae) (Wagner and Pohl, 1965; Chuecas and Riley, 1966; Pohl et al., 1968; Radunz, 1968; Jamieson and Reid, 1972), protozoa (Uronema sp., Labyrinthula sp.) (Harrington, G. W., and Holz, G. G., Jr., unpublished), phycomycete fungi (Ellenbogen et al., 1969), invertebrates (Ackman and Eaton, 1966, 1967; Ackman et al., 1970; Culkin and Morris, 1970a, b; Lee et al., 1971), and vertebrates (Kayama et al., 1963a, b; Ackman, 1967; Ackman et al., 1971; Malins and Wekell, 1970). They are synthesized de novo by the photosynthetic planktonic and benthic algae. Marine animals incorporate them intact from their diet, and also biosynthesize them by elongating and desaturating C18 acids such as 18:2 o6, 18:3 w3, and 18:4 o3. Some invertebrates may obtain C20 and C22 polyunsaturates and/or their precursors from seawater directly Received for publication 20 March 1973. through their body surfaces (Testerman, 1972). Heterotrophic algae, protozoa, and the fungi may supply themselves with the C20 and C22 polyunsaturates by de novo synthesis, by direct incorporation from the environment, and by elongation and desaturation of the Cis fatty acids. The most typical marine polyunsaturates are o)3 eicosapentaenoic and docosahexaenoic acids with methylene-interrupted double bonds of the cis configuration; i.e., all-cis, 5,8,11,14, 17-20:5 and 4,7,10,13,16,19-22:6 (Ackman, 1964; Hinchcliffe and Riley, 1971). The cestodes of sharks contain these fatty acids (Buteau et al., 1969, 1971) and it has been assumed that they acquire them from their immediate environment, the contents of the spiral intestine. We have tested the possibility of direct incorporation, by exposing a tetraphyllidean of sharks to [14C] 22:6 o3 and then performing a radiochemical analysis of the lipids of the tapeworm to determine the distribution of the polyunsaturate. Cestodes were chosen as particularly favorable material for an experiment on direct incorporation of 22:6 oj3 since they neither oxidize nor biosynthesize fatty acids de novo (Meyer et al., 1966).