Cod Liver Oil Supplementation Research Articles

Extreme decrease of linoleic acid in renal medulla from rats after a diet supplemented with cod liver oil

Spontaneously hypertensive (SHR) and normotensive rats were fed a diet supplemented with linseed oil or cod liver oil for 22 weeks. The most remarkable finding was an extreme fall of linoleic acid in lipids from renal medulla after cod liver oil supplementation. In free fatty acids (FFA) eicosatrienoic acid (C 2): 3n-9) appeared increased as a sign of essential fatty acid (EFA) deficiency.

Effects of dietary fish oil supplementation on polymorphonuclear leukocyte inflammatory potential.

Polymorphonuclear leukocytes (PMNLs) are an important contributor to inflammation and are thus a part of the pathophysiology of many human diseases. We assessed the effect of fish oil on PMNL inflammatory potential by measuring chemiluminescence and superoxide production before and after six weeks of daily cod liver oil ingestion by healthy volunteers. Phagocytosing PMNLs demonstrated a 27% decrease in chemiluminescence (P less than 0.05) and a 64% decrease in superoxide production (P less than 0.01), following the cod liver oil supplementation. Analysis of PMNL and platelet fatty acids revealed the appearance of eicosapentaenoic acid and a significant decrease in arachidonic acid in both types of cells.

Altered physiological responsiveness and decreased cyclic AMP levels in rat atria after dietary cod liver oil supplementation and its possible association with an increased membrane phospholipid [formula omitted] fatty acid ratio

Rats were given a cod liver oil supplemented diet and a standard diet for 4 months. The cod liver oil supplementation resulted in a marked increase in the 20:5( n−3) and 22:6( n−3) fatty acids and a marked decrease in the 20:4( n−6) fatty acid in phosphatidylcholine and ethanolamine of the atrial membrane. Atria from the cod liver oil treated rats showed a marked decrease in contractile force, heart rate and cyclic AMP (cAMP) levels under basal conditions. Stimulation with noradrenaline (1·10 −6 M) during high oxygen saturation and reoxygenation resulted in an equal increase in the mechanical responses of the two groups in spite of the significantly different levels of cAMP, whereas in hypoxia, both the cAMP level and the contractile force were significantly lower in the cod liver oil treated group. These results indicate that changes in the fatty acid composition of heart membrane phospholipids is associated with changes in adenylate cyclase activity and physiological function of the rat heart and that an increase in the n−3 n−6 fatty acid ratio in membrane phospholipids of the heart results, when oxygen is abundant in enhanced cAMP-independent contractile activity.

Alteration and recovery of bleeding times, platelet aggregation and fatty acid composition of individual phospholipids in platelets of human subjects receiving a supplement of cod-liver oil.

The effect of supplementation with cod-liver oil containing eicosapentaenoic acid (EPA), 20:5 omega 3, on bleeding times, thrombin-induced platelet aggregation, platelet protein, platelet cholesterol, and the level and fatty acid composition of individual phospholipids in the platelets of human subjects was determined. Measurement of these parameters was conducted before the subjects received the supplement (day 0), after they received the supplement for 14 days (day 14), and 14 days after the supplement was terminated (day 28) so as to monitor recovery. The mean bleeding times exhibited a marked increase (by 81%) with supplementation and returned to near basal (day 0) values within 14 days after the supplement was terminated. Cod-liver oil supplementation significantly reduced thrombin-induced platelet aggregation with a partial recovery being exhibited by day 28. The content of phospholipid, cholesterol and protein (microgram/10(9) platelets) was not significantly different (P greater than 0.05) when isolated from the subjects at day 0, 14 and 28, as neither were the composition of individual phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI) and sphingomyelin (SPH)] given as % of total phospholipid. However, the fatty acid compositions of all platelet phospholipids were altered significantly by the fish oil supplement. In PC, EPA rose from 0.3 to 2.9% of total fatty acids and docosahexaenoate from 0.7 to 1.8% concomitant with a drop in arachidonate (from 14.1 to 9.6%) and linoleate (from 10.2 to 7.9%); these levels approached basal levels 14 days after supplementation was terminated.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of variations in dietary protein and of supplements of cod-liver oil on energy digestion and microbial synthesis in the rumen of sheep fed hay and concentrates

SUMMARYEstimates have been made of the amount of energy fermented and the amounts of microbial protein and total fatty acids synthesized in the rumen of sheep given various rations of hay and concentrates. The sheep had re-entrant cannulas in the proximal duodenum. The amount of protein synthesized was calculated from the flow of RNA-N at the duodenum. The change in the amount of total fatty acids between the food and the proximal duodenum was also measured.In Expt 1, six sheep were given a low-protein basal diet and the same diet supplemented with a vegetable protein concentrate with or without tannin treatment. Some 72% of the digestible energy was apparently digested in the rumen and an estimated 150–170 g microbial protein were synthesized per kg organic matter apparently digested in the rumen. Differences due to the dietary treatments in the amount of energy digested and the amount of microbial protein synthesized were small and non-significant.In Expt 2, the effect of a supplement of 20 g/day of cod-liver oil (CLO) on digestion of a mixed diet of hay and concentrates was examined in five sheep. Despite a marked fall in the ratio of acetic acid to propionic acid in the rumen volatile fatty acids when CLO was added, there were no clear differences in the amount of energy fermented in the rumen, which averaged 64% of the digestible energy, or in the efficiency of microbial protein synthesis, which averaged 200 g/kg organic matter apparently digested in the rumen. On the basal diet an increase of 6·7 g total fatty acid/day occurred in the stomach. This was presumably synthesized in the rumen. However when CLO was added to the diet, a decrease of 4·1 g total fatty acid/day was measured.

Response of laying hens fed on a restricted isocaloric intake basis to oil supplementation of a low‐fat ration

AbstractDept. of Agricultural Chemistry, Queen's University, Belfast and Ministry of Agriculture, N. IrelandTwo experiments are described in which varying levels of corn oil or cod liver oil were added to the diet of birds previously maintained from one day old on a low‐fat cornflour‐based diet containing 0–35% linpleic acid. All diets were fed at three different metabolisable energy (ME) intake levels, the birds being fed a weighed quantity of food daily.Neither ME intake nor dietary corn oil or cod liver oil supplementation had any significant influence on egg size. Increasing levels of dietary ME increased the number of eggs laid, the response being very rapid and occurring within the first 28 days. Any effect of dietary com oil was exerted mainly through the size of eggs laid, although these differences in egg size were not great enough to attain statistical significance. The response to dietary corn oil was not as rapid as the response to dietary ME and no significant effect of corn oil was observed until the second 28‐day period. Dietary corn oil increased the efficiency of conversion of dietary ME to egg product but dietary cod liver oil was without effect.

Effect of Feeding Egg Yolk on Liver Lipids of Rats

The deposition of fat and sterol-ester in the livers of animals fed diets rich in cholesterol has been reported by a number of workers. The following is a report of one of a series of experiments made to determine the influence of other dietary constituents than sterol on this lipid deposition in the livers of rats. The experimental diet fed contained dried egg yolk powder 25.3%, extracted casein 12.6%, agar 4%, Osborne Mendel salts 3%, starch 55.1% with supplements of yeast and cod liver oil. This represented egg yolk protein 8.4%, egg yolk lipids 16%, of which 1/16 was cholesterol, 1/4 lecithin. For the control diet the egg yolk powder was first extracted with alcohol-ether and the egg yolk lipid replaced by Crisco. Each experimental group consisted of 8 rats, while there were 12 in the control group, littermates of the experimental animals. The rats were placed on the diet at weaning time. Both experimental and control groups grew extremely well. They were killed after approximately 60 days on the diet. The livers of the experimental animals presented the typical whitish coloration of sterol-fed animals. The average total fatty acid content of the livers was for the males of the experimental group, 9.3%; for the females, 11.7%. For the control groups the corresponding figures were: males 7.5%; females 7.4%. Total cholesterol (digitonid precipitation) for the males of the experimental group was 2.58%; for the females 3.86%. For the control groups the corresponding figures were: males .48%; females .30%. There was very little difference in the free cholesterol in the control and experimental groups. The average for both groups was approximately 0.3%. Likewise the figures for lecithin were not very different, the average for males in both groups being 2.7% and for females in both groups 2.25%. It was noted, however, that the odor of choline, presumably from decomposition of lecithin, was very strong in the tissues of the animals of the experimental group and absent in those of the control group.

Fundamental Food Requirements for Growth of Rat. V. Influence of Fat in Diet.

Evans and Burr have postulated the existence of a new vitamin, (F), revealed in part by subnormal growth of rats fed synthetic diets extremely low in fat, and containing sucrose as the source of carbohydrate. Although the first report of their work indicates that the casein and sucrose employed as sources of protein and energy require special purification in order to demonstrate the existence of the new vitamin, later, more detailed, reports show that little improvement is secured with commercial casein and sucrose. However, great improvement in growth is noted when fat is included in the diet or when liver or lettuce is fed in addition to the usual supplements of yeast and cod liver oil. Evans and Lepkovsky have offered a partial explanation of these results in the hypothesis of a sparing action of fat on the antineuritic vitamin requirement for growth, but this view does not explain the beneficial effects of the lettuce and liver. We present here the results of several experiments with rats fed diets containing various proportions of fat without lettuce or liver supplements. Data are given for both sexes. The casein was in all cases the highly purified product described elsewhere. Commercial sucrose was used in the sugar diets. The dextrin was tapioca autoclaved at 260° F. for at least 6 hours. All the fat diets contained at least 9% butterfat, the remainder of the fat being crisco or lard. Salt mixture, either McCollum's No. 185 or Osborne and Mendel's, comprised 4% of the diets. Except for Groups No. 4 and No. 9 each rat received separately each day pure dry yeast (Northwestern Yeast Company) and cod liver oil. The daily quantity of yeast was 600 mg. for Groups Nos. 2, 3, 5, 6, 8, and 10, 400 mg. for Group No. 9, 250 mg. for Group No. 1. The quantity of cod liver oil fed was 160 mg. for Groups Nos. 2, 3, 5, 6, 8, and 10, and 500 mg. for Group No. 9.

Relation of the Antirachitic Factor to Reproduction in Birds.

Some years ago it was shown that hen's eggs are especially rich in the antirachitic factor, an observation which has been confirmed repeatedly. We have since found that the eggs of other animals, for example those of various fish and of serpents, likewise contain a large amount of this specific factor, the concentration varying considerably. In the hen the concentration is greater in the egg than in the liver. Several investigators have shown that the content of the antirachitic factor in hen's eggs varies according to their diet and the degree of exposure to ultra-violet rays, and furthermore than when this factor is notably deficient a marked lack of hatchability results. This failure to hatch has been attributed to defective absorption of calcium from the shell into the yolk. From last summer until this spring one group of hens has been placed on a diet devoid of the antirachitic factor (a grain mixture, including yellow corn, also meat scrap and 1 part of sodium chloride) but otherwise complete, whereas another group has been given daily supplements of cod liver oil. Our experience may be summarized by the statement that the group on the deficient diet laid comparatively few eggs even during the productive period of March and April, that these eggs contained very little of the antirachitic factor, that fertile eggs failed to hatch, and that the livers of these hens were also lacking in this substance. It should be added, however, that the blood serum of both groups of hens was found to contain a high percentage of calcium in the spring, that is during the productive season, in spite of the fact that one of the groups was laying and hatching normally, whereas the other was almost inactive in this respect.