Absorption Of Polyunsaturated Fatty Acids Research Articles

Polyunsaturated Fatty Acids (PUFAs): Sources, Digestion, Absorption, Application and Their Potential Adjunctive Effects on Visual Fatigue.

When the eyes are exposed to the environment, they are easily affected by strong light stimulation and harmful substances. At the same time, prolonged use of the eyes or incorrect eye habits can cause visual fatigue, which mainly manifests as eye dryness, soreness, blurred vision, and various discomforts. The main reason for this is a decline in the function of the eye, especially the cornea and retina on the surface of the eye, which have the greatest impact on the normal function of the eye. Research has found that supplementation with appropriate foods or nutrients can effectively strengthen the eye against external and internal stimuli, thereby alleviating or avoiding visual fatigue. Among these, supplementation with polyunsaturated fatty acids has been found to be effective at protecting eye health and relieving visual fatigue. This article summarizes the sources of polyunsaturated fatty acids (including the main dietary sources and internal synthesis), the mechanisms of digestion and absorption of polyunsaturated fatty acids in the body and the safety of polyunsaturated fatty acid applications. It also reviews the mechanism of action of polyunsaturated fatty acids in aiding the relief of visual fatigue based on the mechanism of impaired function or structure of the ocular surface and fundus in the hope of providing some reference and insight into the development and application of polyunsaturated fatty acids in functional foods for the relief of visual fatigue.

Soybean lecithin as an alternative energy source for grower and finisher broiler chickens: impact on performance, fatty acid digestibility, gut health, and abdominal fat saturation degree.

An experiment was performed to assess the inclusion of soybean lecithin (SL) in the replacement of soybean oil (SO), for grower and finisher broiler chicken diets (up to 15 d of life), and its effects on performance, fatty acid (FA) absorption, gut health, and saturation degree of the abdominal fat pad (AFP). A total of 1,440 female Ross-308 chickens were distributed in 60 pens and were fed 5 experimental diets. The control diet (T1) was supplemented with SO (grower and finisher diets at 2.00%), and 4 levels of SL were included in replacement: T2 (0.25% in grower and 0.50% in finisher diets), T3 (0.50% in grower and 1.00% in finisher diets), T4 (0.75% in grower and 1.50% in finisher diets), and T5 (1.00% in grower and 2.00% in finisher diets). At day 39, titanium dioxide was added to finisher diets at 5 g/kg to perform a digestibility balance. At day 46, AFP, tissue, and gut digesta samples were collected to characterize FA digestibility, adipose saturation degree, microbial groups, and histomorphometry. No effects were associated with SO replacement by SL on performance (P > 0.05), ileal digestibility of total, saturated and monounsaturated FA (P > 0.05), nor jejunal morphology (P > 0.05). Total replacement of SO by SL reduced ileal absorption of polyunsaturated FA (P < 0.02) and increased jejunal Lactobacillus spp. counts (P = 0.049). Higher levels of SL inclusion (T4 and T5) lowered polyunsaturated FA concentration of the AFP (P = 0.002) and, thus, slightly reduced its unsaturated-to-saturated FA ratio (P = 0.005). Soybean lecithin inclusion did not modify performance parameters, total FA absorption, nor jejunal morphology, however caused changes on polyunsaturated FA absorption, jejunal microbiota, and saturation degree of the AFP. The study demonstrates that soybean lecithin can be included, in combination with or in replacement of soybean oil, as an alternative energy source for grower (up to a 1%) and finisher broiler diets (up to 2%).

Maternal Immunoglobulins in Infants-Are They More Than Just a Form of Passive Immunity?

In the present review, we highlight the possible “extra-immunological” effects of maternal immunoglobulins (Ig) transferred to the blood circulation of offspring, either via the placenta before birth or via the colostrum/milk across the gut after birth in different mammalian species. Using the newborn pig as a model, since they are naturally born agammaglobulinemic, intravenously (i.v.) infused purified serum Ig rapidly improved the vitality, suckling behavior, and ensured the survival of both preterm and term piglets. In further studies, we found that proper brain development requires i.v. Ig supplementation. Studies have reported on the positive effects of i.v. Ig treatment in children with epilepsy. Moreover, feeding newborn pigs an elementary diet supplemented with Ig improved the gut structure, and recently a positive impact of enteral or parenteral Ig supplementation on the absorption of polyunsaturated fatty acids (PUFAs) was observed in the newborn pig. Summarized, our own results and those found in the literature, indicate the existence of important extra-immune effects of maternal Ig, in addition to the classical protective effects of transferred maternal passive immunity, including effects on the development of the brain, gut, and possibly other organ systems in the neonate. These additional properties of circulating Ig could have an impact on care guidelines for human neonates, especially those born prematurely with low plasma Ig levels.

Manipulation of Omega-3 PUFAs in Lamb: Phenotypic and Genotypic Views.

A number of studies have shown that dietary omega-6 and omega-3 long-chain fatty acids can be incorporated into muscle tissue of ruminants despite the biohydrogenation of dietary fatty acids in the rumen. The main focus of this review is on eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) fatty acids because health authorities around the world consider the sum of these fatty acids as the basis of classifying a food as a source or good source of omega-3 polyunsaturated fatty acids (PUFAs). A high proportion of polyunsaturated fatty acids are hydrogenated in the rumen, leading to a higher concentration of 18:0, but some escapes the rumen to be absorbed intact by the small intestine. Feeding strategies for ruminants have been successfully applied to increase the absorption of PUFAs in the small intestine and therefore to increase the levels of PUFAs in muscle tissue. Protected fats and algae are strong candidates to improve the nutritional value of red meat in ruminants in terms of health-claimable omega-3 fatty acids. Efforts to understand the genetic basis of fatty acid metabolism have been underway. The knowledge of the main genes which control the output of omega-3 fatty acids is still lacking, but gene expression studies have helped to explain the deposition of these acids in muscle, liver, and subcutaneous fat.

Characterization of the n-3 polyunsaturated fatty acid enrichment in laying hens fed an extruded flax enrichment source

The time required to reach a plateau of n-3 polyunsaturated fatty acid (PUFA) concentration in plasma and egg yolk and dynamics of the enrichment process were examined in laying hens. A group of 75 Lohmann White Leghorn layers (65 wk) were fed one of 3 diets: control, moderate, or high n-3 PUFA-enriched diet for 18 d. Diets provided similar ME and CP and contained 0, 7.5%, or 15% LinPRO (source of n-3 PUFA), respectively. Prior to dietary treatment, baseline values were established for the BW, fatty acid composition in egg yolk on a whole-egg basis, and in plasma. These measurements were repeated at 6, 12, and 18 d of feeding. Enzymatic conversion rates of linolenic acid (LNA) to long-chain fatty acids were calculated. Data were analyzed with Proc Mixed of SAS, and broken stick analysis was used to determine n-3 PUFA plateau using the NLIN procedure of SAS (P < 0.05). The total egg yolk n-3 PUFA reached a plateau of 343.7 mg/egg and 272.9 mg/egg after 6.6 and 5.9 d on the high and moderate diets, respectively. In blood plasma, the n-3 PUFA concentrations reached saturation in 7.2 d with 0.93 mg/mL and 0.67 mg/mL on high and moderate diets, respectively. The transfer efficiency of total n-3 PUFA from the diet to the egg yolk was calculated as 55.6% in control birds, 30.5% in moderate birds, and 22.2% in high birds, demonstrating reduced transfer efficiency of n-3 PUFA as inclusion in the feed increases. Final egg yolk n-3 PUFA concentrations had a CV of 16.5% compared with 28.5% for plasma. After 12 d, the long-chain n-3 PUFA [eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA)] were significantly higher in egg yolk from hens on the moderate and high enriched diets compared with those from hens fed the control diet, whereas in plasma values did not differ. Broken stick analysis of egg enrichment indicated that high birds reached the target threshold of 300 mg of total n-3 PUFA/egg in 5 d. A significant increase in EPA, DPA, and DHA and reduction in arachidonic acid content in egg yolks from hens fed enriched diets compared with the control diet confirms competition for enzymes during postabsorptive modification of these fatty acids. This work contributes to the understanding of individual hen effects on n-3 PUFA absorption and the effect of level of dietary enrichment with an extruded flax product on final yolk n-3 PUFA concentration.

Effects of season and reproductive state on lipid intake and fatty acid composition of gastrointestinal tract contents in the European hare

We investigated lipid content and fatty acid (FA) composition of gastrointestinal tract contents in free-living, herbivorous European hares (Lepus europaeus). Mean crude fat content in hare stomachs and total gastrointestinal (GI) tracts was higher than expected for typical herbivore forages and peaked in late fall when hares massively deposited body fat reserves. Changes of FA proportions in different parts of the GI-tract indicated a highly preferential absorption of polyunsaturated fatty acids (PUFA). A further reduction of PUFA content in the caecum, along with the appearance of odd-chained FAs in caecum, caecotrophes, and colon content, pointed to a biohydrogenation of PUFA in the hare’s hindgut. GI-tract contents showed significant seasonal changes in their FA composition. Among PUFA, α-linolenic acid peaked in spring while linoleic acid was predominant in late summer and fall, which probably reflected changes in the plant composition of forage. However, independent of seasonal changes, GI-tracts of lactating females showed a significantly (+33%) higher content of linoleic acid, a FA that is known to increase reproductive performance in European hares. This finding suggests that lactating females actively selected dietary plants rich in linoleic acid, a PUFA that may represent a limited resource for European hares.

Digestion and absorption of polyunsaturated fatty acids

Polyunsaturated fatty acids play an important part in the structure and function of cellular membranes and are precursors of lipid mediators which play a key role in cardiovascular and inflammatory diseases. Dietary sources of essential fatty acids are vegetable oils for either linoleic or alpha-linolenic acids, and sea fish oils for eicosapentaenoic and docosahexaenoic acids. Because of the specificity of the pancreatic lipid hydrolases, triglyceride fatty acid distribution is an essential parameter in the digestibility of fats. The efficiency of the intestinal uptake depends on the hydrolysis and especially on their micellarization. n-3 polyunsaturated fatty acid ethyl ester digestion is recognized to be impaired, but n-3 polyunsaturated fatty acid triglyceride hydrolysis remains a controversial point, and to some authors explains differences observed between vegetable and fish oil absorption. So additional studies are required to investigate this intestinal step. In enterocytes, morphological and biochemical absorption processes involve reesterification of long-chain fatty acids and lipoprotein formation. At this level, specific affinity of I- and L-FABPc (cytosolic fatty acid binding proteins) to polyunsaturated fatty acids requires further investigation. A better understanding of the role of these FABPc might bring to light the esterification step, particularly the integration of polyunsaturated fatty acids into phospholipids. With reference to differences published between fish and vegetable oil absorption, longer-term absorption studies appear essential to some authors. Polyunsaturated fatty acid absorption is thought to be not very dissimilar to that of long-chain mono-unsaturated fatty acid absorption. However, several digestion and absorption specific steps are worth studying with reference to the crucial role of polyunsaturated fatty acids in the organism, and for example adaptation of possible dietary supplements.

Evidence for selective absorption of polyunsaturated fatty acids during digestion in the tobacco budworm, Heliothis virescens F.

Heliothis virescens F., the tobacco budworm, were reared individually on a semi-defined diet. The 5th and 6th instar larvae digested and absorbed approx. 72% of the available dietary lipid. Analysis of the fatty acid composition of total lipid in the diet and that remaining in the faeces indicated that the polyunsaturated fatty acids, linoleate and linolenate, were preferentially absorbed as compared to saturated and monoenoic fatty acids.

未熟児における脂肪吸収に関する研究

The fat metabolism has been studied in premature infants fed with several formula. In this study the auther has analized fatty acid components of several kinds of dried milk powder, the trade marks of which were M., L., E., P., S. and N., and also examined the relationship between their fat absorption and the growth of the premature infants.The results of this study are summarized as follows:1) The fat content was 18.0% in M.,17.0% in L.,14.0% in E.,6.6% in P.,27.6% in S. and 24.0% in N. milk powder.2) The linoleic acid content in the fat of each milk powder was 11.5% in M.,12.7% in L.,1.6% in E.,2.4% in P.,19.4% in S. and 12.7% in N., respectively.These linoleic acid content occupy 3.0%,3.3%, O.3%, O.2%,6.6% and 3.8% of the total calory of each milk powder.3) The components of the fatty acid in the feces were noted to be influenced by the components of the fatty acid in the milk powder taken by the infants. The fatty acid components in the feces were different in some extent among each individual, even though they were fed with the same milk powder. However, any significant difference was not found in a single case when the fatty acid components of the feces were assayed according to the course of days after birth.4) Some different results were observed between the weight method and the chrom green method to measure the rate of fat absorption. From the results obtained, it is concluded that the chrom green method should be performed to obtain an exact result.5) The rate of fat absorption was not influenced by both age and body weight of the premature infants, but it decreased markedly when more fat was given to them. However, as for the absolute quantity of fat absorbed, it increased when more fat was taken by the infants.6) The rate of fatty acid absorption was not connected with both age and body weight of the premature infants, and the rate of fat absorption was pararell,, neniethitehrer with the rate of absorption of oleic acid nor with that of linoleic acid..7) As the fat contents of feces did not show any marked change even after the intestinal flora was suppressed by administration of antibiotics, the intestinal bacilli were not considered to give a significant influence upon the fat absorption.8) The rate of absorption of poly-unsaturated fatty acids including linoleic acid was not so high, comparing with the rate of fat absorption.9) Both the rate and absolute quantity of absorption were very low as far as the linoleic acid of E. milk was concerned, while the rate of fat absorption of E. milk was the highest among the examined milk. On the other hand, those of the linoleic acid of L. milk were most excellent.10) The increase of body weight was most excellent in the premature infants fed with M. milk or L. milk, while it was not so good in the premature infants fed with E. milk. The latter fed with E. milk, however, did not show any significant clinical signs which might be caused by essential fatty acid deficiency such as anorexia, abnormal changes of the feces, or appearance of the dermal symptomes did not occur.11) Many attempts are being tried to improve the dried milk powder at present, the ideal of which is the breast milk, but the fatty acid components of the breast milk are not always the same; they are found to be varied according to the differences of race, climate, food and the course of days after the delivery. It is one of important problems, in which percentage the fatty acid of the milk should be contained.The auther has made it certain that milk powder which contained linoleic acid in 3 to 4 per cent of whole milk calory braught the most excellent growth in the premature infants whose birth weight were over 1500g.