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Fish Oils, Omega-3 Fatty Acids and Male Fertility
Abstract
Over the last three decades, the potential role of omega-3 polyunsaturated fatty acids on health and disease has been a worldwide center of attention. In the western typical diet, the omega-6 to omega-3 fatty acid ratio is at least 10 to 1, likely due to the high prevalence of vegetable oils (such as soybean oil, corn oil and sunflower oil) rich in omega-6 fatty acid. Since excessive amounts of omega-6 fatty acids contribute to rising incidence of many chronic diseases such as cardiovascular disease and whereas increasing omega-3 fatty acid intake cause a protective effect, a more balanced omega-6 to omega-3 fatty acid ratio is recommended (omega-6 to omega-3 fatty acid ratio between 1 to 1 and 3 to 1). A good natural source of omega-3 polyunsaturated fatty acid is seafood and particularly fish oil. Fish and marine products contain two major omega-3 polyunsaturated fatty acids - eicosapentaenoic acid (EPA) and docosahexaemoic acid (DHA) - both of which appear to be beneficial for cardiovascular prevention, immune function, inflammatory response, infant development and mental health. Fish oils may also improve female fertility (ovulatory processes, premature birth and lactation). Although there is a large amount of information available on fish oil, omega-3 fatty acid supplement and their pleiotropic beneficial effects on global health, it is sometimes misleading and not always support by scientific findings, in particular in the case of male reproductive health. Therefore, this review considers the role played by fish oils supplement in male fertility, with large references to human and various animal models (pig, horse, cattle, fowl, rabbit and sheep). Many of the male fertility problems can be related to oligospermia (a low sperm count) or a poor sperm quality (cell with abnormal shape or low motility). In the management of male fertility, omega-3 polyunsaturated fatty acids like others nutrients (vitamins, minerals, zinc, etc.) play a key role in reproductive health. Sperm cells require highly polyunsaturated fatty acids, in particular a high proportion of DHA to provide optimal cell membrane fluidity essential to sperm motility and fertilization success (acrosomal reaction and oocyte penetration). Some studies have suggested that subfertility could be related to the low DHA sperm content. As reported in human, in pig, and several others animal models, fish oil diet can alter significantly sperm fatty acid composition by increasing DHA and EPA content and modify omega-6 to omega-3 fatty acid ratio. Some studies have underlined the potential benefit of fish oil supplement on sperm count. However this effect is more controversial since a diet rich in energy or in proteins also increase sperm production. In fact, dietary omega-3 polyunsaturated fatty acids can affect male fertility directly by modifying sperm membrane composition but also indirectly through various mechanisms: prostaglandin synthesis, steroid metabolism and gene expression. In parallel to the benefit of consuming fish oil is the concern about potential harmful effects on male reproductive health. Because of his high polyunsaturated fatty acid content, sperm cells have a strong oxidative potential. In normal conditions, there is a balance between the generation of oxidants and antioxidant defense mechanisms. Dietary fish oil can induce an additional oxidative stress to the cell which is detrimental for sperm membrane fluidity and DNA integrity. In fact, it is suggested that any fish oil supplementation should be accompanied by antioxidants like vitamins E and C.There is also evidence that adding omega-3 polyunsaturated fatty acid to the diet can influence prostaglandin synthesis which could have an effect on testosterone secretion. Because chemicals such as PCB, pesticides, and sex hormones are fat-soluble, fish and fish oil can also be a dietary source of contaminants that may have deleterious effect on male reproduction. In conclusion, dietary fish oil may help to improve male fertility by increasing omega-3 polyunsaturated fatty acids in sperm cells and would be most beneficial with sperm of initial poor quality. However, a particular attention must be taken in regard to antioxidant supplementation.
Rabbits are classified as obligate herbivores. However, under natural conditions, some members of the family Leporidae incorporate animal products into their diets. Therefore, it seems biologically justified to supplement the diets of farmed rabbits with feeds of animal origin as sources of protein, fat and minerals. The aim of this review was to describe, from a historical perspective, the use of various feeds of animal origin in rabbit nutrition. The applicability of by-products from mammal, poultry, fish and invertebrate processing for rabbit feeding was evaluated, including the future prospects for their use. A review of the available literature revealed that various animal-based feeds can be valuable protein sources in rabbit diets, but their inclusion levels should not exceed 5-10%. Studies investigating their efficacy have been conducted since the 1970s. In some regions of the world, the use of animal-derived protein in livestock feeds was prohibited due to the risk of spreading bovine spongiform encephalopathy (BSE). However, the interest in animal by-products as protein sources in livestock diets is likely to increase since the above ban has been lifted.
The aim of the study was to investigate the effect of dietary fish oil supplementation on the semen characteristics of the Markhoz buck. Sixteen bucks were randomly allocated into 4 groups and received four different diets: unsupplemented control diet, supplemented with fish oil at 2.50% dry matter (DM), supplemented with fish oil (2.50% DM) and vitamin E (0.30 g/kg DM), and supplemented with vitamin E (0.30 g/kg DM). All experimental diets were formulated according to AFRC (1998). Semen was collected at 14 d intervals from June 17, 2006 to September 2, 2006. Semen characteristics were evaluated. Significant effects (p
To assess the effects of dietary fat source on semen quality and fertility, either poultry fat or menhaden oil (MO) was included in broiler breeder male diets. Males received diets containing either poultry fat or MO from 0 to 65 wk of age. When males were 47 wk of age, hens were inseminated every third week through 65 wk with 7.5 × 10⁷ sperm. Fertility and hatch data were collected by incubating eggs laid during each 2-wk post-insemination (WPI) period. The approximate number of sperm that penetrated the perivitelline membrane of the ovum was determined from eggs laid on the eighth day post-insemination. Sperm mobility index was measured at 60 and 63 wk of age from all males producing semen.
When males were provided MO, fertility and hatchability of eggs set from the second WPI were greater by 6.4 and 6.9%, respectively. Testis weight, sperm mobility index, sperm holes in the ovum, and the number of males producing semen were similar between treatments. Although most reproductive characteristics were similar, fertility during the second WPI was significantly enhanced by providing dietary MO. This suggests that sperm from males consuming MO may have persisted in sperm storage tubules for longer periods.
The fatty acid composition of sperm affects the fertilization rate. The objective was to investigate the effects of dietary fish oil (as a source of n-3 fatty acids) on semen quality and sperm fatty acid composition in sheep. Eight Zandi fat-tailed rams were randomly allocated into two groups and fed either a control diet or a diet supplemented with fish oil. Both diets were isocaloric and isonitrogenous and were fed for 13 weeks, starting in the middle of the breeding season. Semen samples were collected weekly and their characteristics evaluated by standard methods, whereas samples collected at the start and end of the study were assessed (gas chromatography) for sperm lipid composition. Mean (±s.e.m.) sperm concentrations (4.3 × 109 ± 1.3 × 108 v. 3.9 × 109 ± 1.3 × 108 sperm/ml and percentages of motile (77.25 ± 3.34 v. 60.8 ± 3.34) and progressively motile sperm (74.13 ± 1.69 v. 62.69 ± 1.69) were significantly higher in the fish oil group than control. Dietary fish oil increased the proportion of docosahexaenoic acid (DHA, C22:6 n-3) in sperm fatty acid composition. We concluded that feeding fish oil as a source of n-3 fatty acids attenuated seasonal declines in semen quality in rams, perhaps through increased DHA in sperm.
Fish oil supplements have become a popular means of increasing one's dietary intake of essential polyunsaturated fatty acids. However, there is growing concern that the levels and potential health effects of lipophilic organic contaminants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) may diminish some of the health benefits associated with the daily consumption of fish oil supplements. In this study, ten over-the-counter fish oil supplements available in the United States were analysed for PCBs and PBDEs and daily exposures calculated. Based on manufacturers' recommended dosages, daily intakes of PCBs and PBDEs ranged from 5 to 686 ng day(-1) and from 1 to 13 ng day(-1), respectively. Daily consumption of fish oil supplements expose consumers to PCBs and PBDEs. However, in comparison with fish ingestion, fish supplements may decrease daily PCB exposure and provide a safer pathway for individuals seeking to maintain daily recommended levels of polyunsaturated fatty acids.
The aim of this study was to evaluate the effects of dietary supplementation with different fish oils (rich in PUFA) vs. hydrogenated animal fat (SFA) on semen production and quality, fatty acid composition, and preservation properties in boars under controlled and commercial conditions. In Exp. 1 (in a research station), 44 boars, allocated to 4 dietary treatments, received daily 2.5 kg of basal diet with a supplement of 1) 62 g of hydrogenated animal fat (AF, n = 12); 2) 60 g of menhaden oil containing 18% docosahexanoic acid (DHA) and 15% eicosapentanoic acid (EPA; MO, n = 11); 3) 60 g of tuna oil containing 33% DHA and 6.5% EPA (TO, n = 11); and 4) 60 g of menhaden oil and 2 mg/kg of biotin (MO+B, n = 10). Biotin is a critical factor in the elongation of PUFA. Semen was collected according to 3 successive phases: phase 1 (twice per week for 4 wk); phase 2 (daily collection for 2 wk); and phase 3 (twice per week for 10 wk). Experiment 2 was conducted in commercial conditions; 222 boars were randomly allocated to AF, MO, and TO treatments. Semen was collected twice weekly over a 6-mo period. All diets were balanced to be iso-energetic and provided an equivalent of 989 mg of vitamin E per day. Classical measurements of sperm quantity and quality were done for both experiments. Experiment 1 showed, after 28 wk of supplementation, a massive transfer of n-3 PUFA into sperm from boars fed fish oil diets (MO and TO). No differences were observed among dietary treatments for libido (P > 0.30), sperm production (P > 0.20), or percentage of motile cell (P > 0.20). Unexpectedly, MO+B diet reduced the percentage of normal sperm compared with the other treatments (P < 0.03). In conclusion, although it modified the fatty acid composition of sperm, supplementation of boars with dietary fish oils, rich in long chain n-3 fatty acids, did not influence semen production or quality postejaculation.
The present work aimed to compare the effect of dietary flax with other oil sources on rooster sperm membranes and on semen characteristics. White Leghorn roosters (16 per diet) were fed 1 of 4 treatments: control diet (CON), or a diet containing corn oil (CORN), fish oil (FISH), or flax seed (FLAX) as the lipid source. Semen from 4 birds (30 wk old) of each treatment was pooled, the sperm head (HM) and body membranes (BM) were isolated, and lipids were extracted and analyzed. Aspects of lipid composition tested were as follows: percentage of individual fatty acids (C14:0 to C24:1) in total fatty acids, percentage of fatty acid categories [saturated, monounsaturated, polyunsaturated (PUFA), n-3 and n-6 PUFA, and n-6:n-3 ratio] within total fatty acids, and percentage of phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol, phosphatidylserine, and sphingomyelin] in total phospholipids. Sperm characteristics evaluated were as follows: volume, concentration, viability, percentage of motile cells, average path velocity, track speed, progressive velocity, lateral head displacement, straightness, and linearity. Diet did not affect membrane phospholipid ratios in either membrane but modified major fatty acids within certain phospholipids. Birds fed FISH and CORN showed, respectively, the highest and the lowest n-3 in sperm, causing reciprocal significant changes in n-6:n-3 ratio. Feeding FLAX caused intermediate effects in n-3, with values significantly lower than FISH but higher than CORN in HM (PC, PE, and phosphatidylinositol) and PC in BM (P < 0.05). In the PE phospholipids, FISH, followed by FLAX, increased n-3 in BM and decreased n-6 PUFA in HM. Sperm concentration was specifically correlated with the amount of 20:4n-6 in FLAX and 22:4n-6 in CON. In FLAX diets, straightness correlated with C18:0, n-3, and n-6:n-3 ratio. Diets containing distinct lipid sources differentially modify the lipid contents of HM and BM, with minor effects on sperm characteristics. Flax seed produced changes similar to fish oil and could be used as a substitute.
Chicken and turkey spermatozoal lipids were separated into acidic and non-acidic fractions by DEAE cellulose column chromatography. The phospholipid composition of each fraction was examined by thin-layer chromatography, followed by phosphorus analysis.
Chicken sperm phospholipid comprised 38.21% phosphatidyl choline, 9.04% phosphatidal choline, 12.62% phosphatidyl ethanolamine, 8.04% phosphatidal ethanolamine, 8.28% sphingomyelin, 9.76% phosphatidyl serine, 6.56% phosphatidyl inositol, and 7.49% cardiolipin.
Turkey sperm phospholipid comprised 34.15% phosphatidyl choline, 7.14% phosphatidal choline, 15.61% phosphatidyl ethanolamine, 11.34% phosphatidal ethanolamine, 9.91% sphingomyelin, 8.83% phosphatidyl serine, 4.80% phosphatidyl inositol, and 8.22% cardiolipin.
Experiments were conducted to assess whether changing dietary fat composition altered phospholipid composition of rat testicular plasma membranes in a manner that altered receptor-mediated action of luteinizing hormone (LH)/human chorionic gonadotropin (hCG). Weanling rats were fed diets that provided high or low cholesterol intakes and that were enriched with linseed oil, fish oil or beef tallow for 4 wk. Feeding diets high in (n-3) fatty acids decreased plasma and testicular plasma membrane 20:4(n-6) content. A marked reduction of the 22:5(n-6) content and an increase in the 22:6(n-3) content of testicular plasma membrane was found only in animals fed fish oil. A decrease in binding capacity of the gonadotropin (LH/hCG) receptor in the plasma membrane, with no change in receptor affinity, was observed for animals fed either linseed oil or fish oil diets. Dietary treatments that raised plasma membrane cholesterol content and the cholesterol to phospholipid ratio in the membrane were associated with increased binding capacity of the gonadotropin receptor. Feeding diets high in 18:3(n-3) vs. those high in fish oil altered receptor-mediated adenylate cyclase activity in a manner that depended on the level of dietary cholesterol. Feeding diets high in cholesterol or fish oil increased basal and LH-stimulated testosterone synthesis relative to that in animals fed the low cholesterol diet containing linseed oil. It is concluded that changing the fat composition of the diet alters the phospholipid composition of rat testicular plasma membranes and that this change in composition influences membrane-mediated unmasking of gonadotropin receptor-mediated action in testicular tissue.
The oxidative metabolic capability of mature boar spermatozoa has been determined in vitro. The high rate of oxidation of fructose, glucose, glycerol, glycerol-3-phosphate and lactate to CO2 and the optimization of incubation conditions indicates that these cells could constitute a model system for investigating the anti-glycolytic activity of potential male anti-fertility agents. The effects of several chemical agents on the oxidative metabolism of boar spermatozoa are reported.
Lipid and fatty acid analyses have been made on the testes of 16 human subjects obtained at orchidectomy. About 60% of the total lipid was phosphatide, 12% triglyceride, 6% free cholesterol and 2% esterified cholesterol. Phosphatidyl choline was the chief phosphatide present, followed by phosphatidyl ethanolamine. Other phosphatides were phosphatidyl serine, phosphatidyl inositol and sphingomyelin. The major saturated fatty acids found in the total lipids were palmitic and stearic while the major monoenoic acid was oleic. A 20 carbon triene of the linoleic acid family (20:3 w6) was present in significant quantities together with arachidonate and 22:6 w3. Only small amounts of 22:5 were present and isomers of both the linoleic and linolenic acids were present in this fraction. Histological studies revealed active spermatogenesis in over 50% of the testes analysed. In 5 cases with marked tissue degeneration, the concentration of total phosphatides was lower than in the other samples. In 4 of these, the concentration of 22:6 was lower than in the other samples. It is suggested that this polyenoic acid may be associated with the testicular germinal cells.
Spermatological investigations were performed in volunteers treated with fish oil 9 g/die for 28 days and compared with results after 4 and 12 weeks. Fish oil causes no decrease of sperm quality or quantity in the tested dosage, so there is no evidence of toxicity in respect of spermatogenesis. After 12 weeks sperm density was increased (2α = 0,1), while the number of spermatozoa per ejaculate increased significantly (2α = 0,01). This increase cannot be regarded as a therapeutic effect, since there is coincidence with annual changes.
Crude fish oil is an important ingredient in fish feed for fish farming; it can be used as functional food or neutraceutical (cod liver oil, EPA/DHA concentrates) or incorporated in healthy foods after refining. Major components of fish oil have positive nutritional properties. Polyunsaturated fatty acids can go up to 40% with variable proportions of EPA (C20:5) and DHA (C22-6) [ω-3 fatty acids]. Content of fat soluble vitamins is usually high. Unfortunately, fish oil is also sensitive to degradation products (polymeric and oxidized fat, increased polar content, off-flavor problems⋯). The beneficial nutritional properties of fish oil are in great contrast with the presence of heavy metals and persistent organic pollutants (POPs) such as polychlorinated dibenzo-dioxins and-furans (PCDDs/PCDFs) and polychlorinated biphenyls (PCBs), mainly originating from the environment. Usual steps for fish oil refining are neutralization, bleaching, winterization (optional) and deodorization. Processing difficulties consist in finding the best operating conditions for an effective removal of unwanted contaminants and a maximal preservation of the nutritional qualities (processing duality). In this work, different adsorbents (filter aid, silica powder, bleaching earth and active carbon) were tested for the best removal of PCDDs/PCDFs and PCBs; it was shown that filter aid, silica and bleaching earth have no significant effect on decontamination while removal of majority non ortho PCBs and PCDDs/PCDFs was possible with active carbon. Mono-ortho PCBs were significantly less absorbed by active carbon. Deodorization was further investigated. Processing temperature had a very pronounced effect on the reduction of PCDDs/PCDFs and PCBs. Already at 210 °C, all of them were removed efficiently to a level below the limit set by European Legislation. But temperature increase was limited by the risk of degradation of EPA/DHA (ω-3). Combination of active carbon treatment and deodorization was shown to be the best compromise to remove majority of the contaminants and to preserve the nutritional quality of fish oil. At low active carbon dosage and deodorization temperature below 200 °C, the total contamination level of PCDDs/PCDFs and PCBs can be reduced below level imposed by European Legislation.
The aim of the present study was to examine the role of several polyunsaturated fatty acids (PUFA) in the control of steroidogenesis in the goldfish testis. The release of fatty acids from testis tissue in response to the protein kinase C activator phorbol-12-myristate-13-acetate (PMA) and calcium ionophore A23187 was studied. After a 2-h incubation, goldfish testis tissue released detectable amounts of several fatty acids, particularly docosahexaenoic acid (DHA). Treatment with PMA (100 nM) and A23187 (1 microM) increased the release of arachidonic acid (AA) and, to a lesser extent, of eicosapentaenoic acid (EPA). Further experiments showed that AA (100 and 400 microM) and, to a lesser extent, eicosatrienoic acid (ETA; 400 microM)--but not EPA or DHA (both 400 microM)--stimulated testicular testosterone (T) production via an indomethacin (INDO; 40 microM)--sensitive pathway, suggesting that these effects may be mediated through conversion to prostaglandins (PG). E-series PGs formed directly from ETA, AA, or EPA (PGE1, PGE2, or PGE3, respectively) all stimulate T production, with relative potencies of PGE2 > PGE1 > PGE3. The inability to detect ETA release from testis incubates and the limited effect of EPA on steroid production suggest that PGE2 represents the predominant E-series PG formed under physiological conditions in the goldfish testis. The steroidogenic action of AA was blocked by treatment with EPA or DHA, and this effect is due, partly, to inhibition of PGE2 formation from AA.(ABSTRACT TRUNCATED AT 250 WORDS)
The effect of reaction conditions on transesterification of tuna oil with n-3 fatty acid methyl ester (n-3 FAME) using sodium methoxide as catalyst was studied. The lipid and fatty acid composition of the reaction products were analyzed. The time course of the reaction indicated that the highest incorporation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) occurred after 5 h, and did not change significantly during the next 20 h (P > 05). The catalyst concentration of 1.5% w/w of reactants
showed the highest incorporation of EPA and DHA. Incorporation of EPA and DHA were increased with increasing reaction temperature (P < 0:05) and the highest incorporation was observed at 80C. The highest EPA and DHA incorporation occurred at a mole ratio of tuna oil and n-3 FAME of 1:4. The recovery of triglyceride was decreased with the increasing of all reaction factors. Tuna oil enriched with n-3 fatty acids was successfully produced by chemical interesterification.
The major polyunsaturate in phospholipids of chicken spermatozoa is docosatetraenoic acid, 22:4n-6, which is positively correlatable with sperm motility and fertility. The potential for dietary manipulation of sperm fatty acid in order to improve male fertility has been extensively studied in the chicken. The effects of diets enriched in n-3 and n-6 long chain polyunsaturates have been investigated in different trials using different oil sources and levels of oil inclusion.The 22:6n-3 and 22:5n-3 content of avian spermatozoa is increased by supplementing the feed with fish oil (rich in 22:6n-3) and linseed oil (rich in 18:3n-3) respectively. The 22:4n-6 content is also increased by supplementing the feed with evening primrose oil (rich in 18:3n-6) in association with high level of vitamin E (200 mg/kg) and with arasco oil (rich in 20:4n-6). The effects of these fatty acid manipulations on sperm quality and/or fertility are reviewed. Both n-3 and n-6 rich diets showed a positive effect on sperm movement during the reproductive period and an age-dependent positive effect on fertility. Reported effects of n-6 rich diets on semen production have been variable with 20:4n-6 rich diet having a positive effect on semen volume and thus on total sperm number and 18:3n-6 rich diets having a negative effect on semen concentration. Spermatozoa enriched in 22:5n-3, or 22:6n-3 or 22:4n-6 result in significantly higher fertility values following artificial insemination compared to control spermatozoa; however, such a positive effect is age dependent and observed at 37 to 42 weeks, but not in older birds.The n-6 fatty acid composition of chicken spermatozoa is recognised as a specie-specific characteristic. The fundamental relation between dietary lipid, spermatozoa fatty acid composition and thus sperm quality and fertility can be seen as having a potential commercial application.
Total phospholipid concentration in stallion sperm was 1.17 ± 0.05 μmole/109 spermatozoa (mean ± S.D., n = 33). Six identified phospholipid components included phosphatidyl choline (27%), sphingomyelin (13%), choline plasmalogen (12%), phosphatidyl ethanolamine (13%), ethanolamine plasmalogen (6%) and cardiolipin (5%).Of the saturated fatty acids, palmitic acid was in highest concentration (22%) with lower concentrations of tridecanoic (6%), myristic (7%), pentadecanoic (11%), stearic (6%), arachidic (1%) and behenic (1%). Unsaturated fatty acids in highest concentration were arachidonic (18%), docosapentaenoic acid (17%), oleic (5%) and docosahexaenoic (8%). The overall ratio of unsaturated to saturated fatty acids in the phospholipids of stallion sperm was 0.90.The concentration (mean ± S.D.) of total phospholipid and glycerylphosphorylcholine (GPC) in stallion seminal plasma were 28.4 ± 20.2 μmole/100 ml and 55.8 ± 30.3 mg/100 ml, respectively.
Der Gehalt an mehrfach ungesättigten Fettsäuren in Relation zur Motilität der Spermatozoen
Die absoluten Mengen der in den Phospholipiden gebundenen Fettsäuren wurden bei Fertilitätsstörungen gaschromatographisch analysiert.
Unsere Ergebnisse zeigen, daß zwischen dem Gehalt an Docosahexaensäure (22:6) und der Spermatozoendichte sowie der Motilität eine signifikante Beziehung besteht.
Diese Erkenntnisse lassen vermuten, daß die Peroxidbildung eine Ursache für den niedrigen Gehalt an Docosahexaensäure in Spermatozoen mit einer schlechten Motilität ist.
The objective was to determine the effect of long-term dietary supplementation of two types of fish oil on lipid composition and steroidogenesis in adult pig testis. Twenty-four Duroc boars, aged 204.5 ± 9.4 d (body weight 128.1 ± 16.7 kg) received daily 2.5 kg of an iso-caloric basal diet supplemented with: 1) 62 g of hydrogenated animal fat (AF); 2) 60 g of menhaden oil (MO) containing 16% of eicosapentaenoic acid (EPA) and 18% of docosahexaenoic acid (DHA); or 3) 60 g of tuna oil (TO) containing 7% of EPA and 33% of DHA. After these diets were consumed for 7 mo, testicular hormones, phospholipid content, and fatty acid composition of individual phospholipids in testis were determined. Body and reproductive organ weights were not significantly affected by dietary treatments. Testicular tissue from boars fed a TO diet, followed by those receiving MO and AF diets, had the lowest level of phosphatidylethanolamine (TO < MO < AF; P < 0.01) but the highest sphingomyelin (TO > MO > AF; P < 0.01). For each phospholipid, boars fed either the MO or TO diet had increased total omega-3 fatty acids, particularly DHA (P < 0.01), by reciprocal replacement of total omega-6 fatty acids (20:4n-6, 22:5n-6). The MO diet increased EPA more than the other diets. Testicular concentrations of testosterone and estradiol were lower in boars fed a TO diet than a MO diet (P < 0.02). In conclusion, long-term dietary supplementation of fish oil, regardless of the EPA/DHA ratio, modified the fatty acid compositions in testis and affected steroid production of healthy adult boars, which may represent a promising models for future studies on fertility.
To evaluate the influence of dietary supplementation of omega-3 polyunsaturated fatty acids (n-3 PUFA) on storage of boar semen, three experiments were conducted: two involved long-term, fresh semen storage (Exp. 1 and Exp. 2), whereas the other involved cryopreservation (Exp. 3). Boars were allocated randomly to three dietary treatments (for 6-7 mo). In addition to a daily allowance of 2.5 kg of a basal diet, they received: 1) 62 g of hydrogenated animal fat (AF); 2) 60 g of menhaden oil (MO), containing 18% docosahexanoic acid (DHA) and 15% eicosapentanoic acid (EPA); or 3) 60 g of tuna oil (TO), containing 33% DHA and 6.5% EPA. In Experiment 1 (n = 26) and Experiment 2 (n = 18), semen was cooled and stored in vitro for several days at 17 °C before assessment, whereas in Experiment 3 (n = 18), viability, motility, acrosomal integrity, susceptibility to peroxidation (LPO), and DNA fragmentation were determined in fresh and frozen-thawed sperm. In Experiment 1, sperm from boars fed TO had better resistance to fresh storage; even after 7 or 9 d of storage at 17 °C, there were more (P = 0.03) motile sperm in boars fed TO (>60%) than in those fed AF or MO. In Experiment 2, fish oil supplementation did not influence any aspect of sperm quality during semen storage (P > 0.10). In Experiment 3, cryopreservation decreased the proportion of motile and viable frozen-thawed sperm as well as acrosomal integrity and increased DNA fragmentation and LPO (P < 0.01) relative to fresh semen, although sperm quality was unaffected by treatments (P > 0.09). In conclusion, although adding fish oil to the diet failed to significantly improve the quality of cryopreserved boar sperm, inconsistent responses of long-term storage of cooled sperm to dietary n-3 PUFA supplementation warrant further investigation.
The aim of the current study was to investigate the effect of feeding a DHA-enriched nutriceutical on the in vitro quality and sperm motility parameters of fresh and frozen-thawed bull semen assessed by CASA. Samples were obtained from nineteen Holstein bulls used for semen collection at Semen Production Center, Karaj, Iran. Control group (n = 10) were fed a standard concentrate feed while treatment group bulls (n = 9) had this standard feed top dressed with 100 g of a commercially available DHA-enriched nutriceutical. Semen quality was assessed on ejaculates collected at the baseline and after 5, 9, and 12 weeks of supplementation. Classical semen evaluation, assessment of sperm motility (subjective and computer-assisted), viability (eosin-nigrosin), and hypo-osmotic swelling test (HOST) were conducted. Semen volume, sperm concentration, and consequently total sperm output were not affected by dietary treatment (P > 0.05). Feeding the nutriceutical was indeed found to affect sperm motility parameters assessed by CASA after 9 weeks of trial. The treatment has improved total motility (P < 0.01), progressive motility (P < 0.05), average path velocity (P < 0.05), HOST-positive (P < 0.01), and proportion of rapid spermatozoa (P < 0.01) in the fresh semen of bulls. Moreover, the proportion of viable spermatozoa increased (P < 0.05) in the ejaculates collected from nutriceutical-fed bulls compared to the control after 12 weeks of feeding trial. The post-thawed HOST and sperm motility data obtained by CASA did not differ between two groups (P > 0.05). On the other hand, dietary supplementation did not affect body weight, BCS and scrotal circumference. Consequently, it can be concluded that dietary DHA supplementation or its precursors, improve in vitro quality and motility parameters of fresh semen assessed by CASA in Holstein bulls. However, this effect was not pronounced in frozen-thawed semen.
The consumption of fish and shrimp containing omega-3 fatty acids can result in protective health effects including a reduced risk of cardiovascular disease, stroke, and diabetes. These protective effects may be decreased by the presence of mercury in the muscle tissue of fish and shellfish. Mercury can increase the risk of cardiovascular problems and impede neurological development. The objective of this project was to determine appropriate consumption amounts of selected fish species and shrimp based on mercury levels and recommended intake levels of omega-3 fatty acids. Species that are high in omega-3s and low in mercury include salmon, trout, and shrimp. Species with both high levels of mercury and omega-3 fatty acids include tuna, shark, and halibut, swordfish, and sea bass.
During the last years, consumption of health supplements has increased in our society. They are recommended as an additional source of minerals, vitamins, omega-3 and omega-6 fatty acids, in the diet. A lot of these supplements contain oils among their components (fish oils or vegetable oils), especially those recommended for their omega-3 content. Due to their persistence and lipophilic characteristics, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (PCBs), marker PCBs, and polybrominated diphenyl ethers (PBDEs) bioaccumulate in fat tissues, especially in those animals, as fish, which show low metabolic capability. Therefore, the consumption of nutritional supplements with oil components can increase the intake of persistent organic pollutants (POPs) through the diet. The aim of this study was to analyse 15 of these supplements commercialized in Spain to determinate their POPs concentrations and their intake for their consumers. Concentrations of POPs in the dietary supplements studied (PCDD/Fs: 0.04-2.4 pg TEQ g(-1); dl-PCBs: 0.01-12.1 pg TEQ g(-1); marker PCBs: 0.17-116 ng g(-1); and PBDEs: 0.07-18.2 ng g(-1)) were in the low-medium range of those reported in literature for other countries. Vegetable oil and mineral-based supplements showed concentrations of POPs clearly lower than those based on fish oil. Among these, those based on cod liver oil presented the highest concentrations detected in the study, exceeding the maximum levels established in European regulations for marine oils for human consumption. In general, the intake of POPs via the consumption of these supplements would be lower than the intake derived from fish consumption.
It has been known that fish oils are prone to contamination by polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs). In this study, the removal of contaminants from fish oil by countercurrent supercritical CO(2) extraction (CC-SCE) and activated carbon treatment was investigated. Fish oil was treated by CC-SCE at 70 degrees C and 30MPa and with a CO(2)/oil ratio of 72; this resulted in a 93% reduction in the sum of PCDDs, PCDFs and DL-PCBs concentration level by and 85% reduction in toxic equivalency (TEQ). CC-SCE uses 40% less CO(2) and yields 30% more refined oil than semi-batch-type processes. Subsequent treatment by activated carbon reduced the concentration level by 94% and TEQ by 93%. CC-SCE is effective for the removal of DL-PCBs, whereas activated carbon treatment is effective for the removal of PCDD/Fs. These results reveal that the combination of CC-SCE and activated carbon treatment is applicable to the removal of PCDD/Fs and DL-PCBs from fish oil.
Organochlorine chemicals are present in the environment worldwide; however, populations living in the Far North are particularly at risk because their traditional diets are mainly composed of contaminated animals (fish, seals, whales, and polar bears). It has been suggested that male fertility is globally declining, possibly because of chronic, low-level exposure to environmental contaminants. This study was designed to assess the effects on fresh sperm fertility parameters using the porcine model of 1) an environmentally relevant mixture of 15 organochlorines and 2) the metabolized extract of this mixture. In the first experiment, the organochlorine mixture (at relative concentrations of 10.5, 14.7, and 21 microg/mL polychlorinated biphenyls [PCBs]) reduced sperm total motility, progressive motility, and viability, and increased capacitation, spontaneous acrosome reaction rates, and cytosolic calcium levels, suggesting that the mixture alters the sperm membrane and is detrimental to sperm function. In the second experiment, the metabolized extract of this organochlorine mixture (at relative concentrations of 0.9, 1.8, 2.7, 3.6, and 4.5 microg/L OH-PCBs) tended to decrease only sperm total motility. In an in vitro porcine model, the mixture of organochlorines, as found in the Arctic food chain, was rapidly detrimental to sperm function at concentrations above environmental levels. In contrast, short and physiologically relevant exposure to the metabolized extract of this mixture induced only limited adverse effects on sperm motility.
The effects of fish oil (FO) and vitamin E (vE) dietary supplementation on semen quality, sperm susceptibility to lipid peroxidation, tocopherols content and fatty acid profiles were studied in rabbits. Fifty-two rabbit bucks randomly divided in four groups received a control diet and enriched diets containing either FO (1.5%, w/w), vE (200mg/kg) or both. Semen volume, concentration, motility and viability were analysed at various time-points and the lipid composition was assessed on sperm cells. The phospholipid fatty acid profile was determined: n-6 PUFA were the major fatty acids found, with a proportion of 42%, whereas the n-3 PUFA accounted for nearly 1%, mainly represented by C22:6n-3 (docosahexaenoic acid, DHA). FO supplementation produced a seven-fold increase in the content of DHA in sperm phospholipids and a comprehensive rearrangement of the phospholipid fatty acid composition, while an unexpected negative effect of feeding high level of vE on the proportion of total PUFA was found. Despite the remarkable changes observed in sperm lipid composition, semen quality parameters were not affected by the dietary treatments and the interaction between the two dietary supplements had a significant effect only on sperm concentration. An increase in semen production by ageing and a concomitant rise in sperm susceptibility to in vitro peroxidation was found. alpha- and delta-tocopherol, present in rabbit sperm in similar amount, were not affected by dietary treatment. delta-tocopherol content had a significant linear negative regression with age and showed a significant negative correlation with the susceptibility to peroxidation values.
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In adult rats, 22:6(n - 3) dietary deficiency does not affect brain membranes, but has a significant effect on some other visceral organs. 60-day-old male rats fed a diet containing sufficient amounts of both linoleic and alpha-linolenic acid were divided into three groups. One group continued the same diet; the second was fed a diet containing 2% sunflower oil, the third was fed 10% sunflower oil (sunflower oil contains linoleic acid, but trace amount of alpha-linolenic acid). Animals were killed different times after receiving the new diets (1 to 31 weeks). For animals fed the diets containing only sunflower oil, deficiency in cervonic acid content (DHA, docosahexaenoic acid, 22:6(n - 3)) was not detected in whole brain, myelin or nerve endings within 31 weeks. In contrast, this acid progressively declined in liver, heart and testes up to 3 weeks and remained nearly stable thereafter. In parallel to the reduction of cervonic acid content, 22:5(n - 6) content increased in liver and heart, but not in testes. It also increased in brain, nerve endings and myelin from week 3, 6 and, 9 respectively. These results suggest that brain cervonic acid is highly preserved or is maintained at the expense of other organs.
Five homogenates of human sperm cells were separately incubated with [14C]arachidonic acid in the presence of reduced glutathione, L-tryptophan, and haematin as cofactors. The cyclooxygenase products of arachidonic acid metabolism were extracted, separated, and measured for their radioactivity. The rate of formation of prostaglandin (PG)D2, PGE2, PGF2 alpha, 6-keto PGF1 alpha, and thromboxane (TX)B2 were 18.0 +/- 1.11, 10.9 +/- 0.68, 5.8 +/- 0.21, 3.9 +/- 0.13 and 6.6 +/- 0.52 pmol/10(6) cells/min, respectively. These results are discussed in relation to the hypothesis that cyclooxygenase metabolites of certain polyunsaturated fatty acids play an important part in the sperm acrosome reaction and fertilization.
The fatty acids in the human retina and the macular region were measured quantitatively (mole percent) by gas chromatography. The major fatty acids of the human retina and macula were palmitic, stearic, oleic, arachidonic, and docosahexaenoic. Surprisingly, there was much less docosahexaenoic acid in the macular region (15.9% of total) than in the peripheral retina (22.3% of total). There was a group of "other fatty acids," not any of the five major fatty acids, that were relatively more abundant in the macula (21.0% of total) than in the peripheral retina (10.7% of total). These results indicate that the human macula has a unique biochemical composition, which differs substantially from the peripheral retina. Establishment of the biochemical composition of the macula may be important for helping recognize possible changes associated with diseases such as age-related macular degeneration.
The objective of this study was to determine the efficacy of linolenic acid [18:3(n-3)], compared with the long-chain (n-3) fatty acids in fish oil, in suppressing arachidonic acid [20:4(n-6)] metabolism in rat testis. Six groups of rats were fed three levels of 18:3(n-3) or fish oil, and the fatty acid composition of testis parenchyma lipids and prostaglandin (PG) I2 synthesis by tunica were determined after 12 wk. Levels of docosapentaenoic acid [22:5(n-6)], the major 22-carbon fatty acid in rat testis lipids, were significantly depressed compared with the control by both linolenic acid and fish oil; however, testis weights were not affected significantly. Arachidonic acid levels also were depressed significantly in testis lipids by dietary (n-3) fatty acids, but the decreases were not as pronounced as those observed in other tissues. The synthesis of PGI2 was significantly reduced compared with the control by (n-3) fatty acid feeding, but there were no differences among the experimental groups. Both 18:3(n-3) and the longer-chain (n-3) fatty acids from fish oil reduce levels of 20:4(n-6) and 22:5(n-6) in testis lipids and the capacity of the tunica to synthesize PGI2, but these fatty acids seem to cause no defect in testicular development as indicated by weight.
Marine oils may offer cardiovascular benefits, but inhibition of prostaglandin E and prostaglandin F synthesis by fish oil has been found in animal studies, and such effects could alter physiological responses in man to a clinically significant degree. Since greater amounts of E and F-type prostaglandins are made in human seminal vesicles than in the rest of the body combined, the influence of n-3 supplements upon semen prostaglandins was assessed in 10 subjects before and after one month of taking 50 ml menhaden oil daily. Prostaglandins E1, E2 and their 19-hydroxy derivatives were measured by HPLC-UV as PGB's, and prostaglandin E3, 19-OH PGE3, and analogous PGF's by gas chromatography/mass spectrometry. Fish oil ingestion reduced concentrations of one- and two series prostaglandins (mean reduction in PGE's = 37%, in PGF's = 20%, p less than 0.05), while more than doubling the low amounts of PGE3 and PGF3 alpha, and their previously undescribed 19-hydroxy derivatives. Semen phospholipids were enriched in eicosapentaenoic acid after dietary fish oil, but sperm counts and motility were not altered during the study. Since dietary fish oil reduces prostaglandin concentration in semen, clinical trials of n-3 fatty acids should also evaluate other possible results of in vivo cyclooxygenase inhibition.
Intramuscular administration of methylmercury (MeHg) into mice at doses of 10 and 20 micrograms per day and animal for 30 days exerts toxic effects on the epididymal histoarchitecture, sperm motility, sperm count and sperm energy metabolism. Scanning electron microscopic study showed changes in the cauda epididymal sperm morphology. All these factors contributed finally to a failure of the fertility in MeHg treated mice as evidenced by a significant reduction in the average number of implantation sites or their absence in females cohabited with treated males. The decline in the serum testosterone levels by high dose indicates a decreased testicular androgen synthesis.
Three cyclooxygenase (prostaglandin synthetase) inhibitors, indomethacin, phenylbutazone, and oxyphenbutazone, decreased fertilization in vitro when mixed with capacitated mouse spermatozoa before addition of the treated gametes to oocytes. Fertilization was inhibited whether the oocytes were intact, follicle cell-free, or both follicle cell-free and zona-free. At various concentrations of inhibitor, no effect was observed on the motility or forward progression of the spermatozoa. These cyclooxygenase inhibitors also decreased the guinea pig acrosome reaction. Inhibition of the acrosome reaction did not occur when a mixture of the prostaglandins (PGE2 or PGF2 alpha) and one of the inhibitors was added to the spermatozoa. Alone, these prostaglandins tended to enhance the rate at which the acrosome reaction took place. Lowered calcium levels reduced the occurrence of the acrosome reaction, an effect that could be reversed at least partially by the addition of PGE2. Even in the nominal absence of calcium, some acrosome reaction took place when PGE2 was present in the medium. These results support an essential role for cyclooxygenase and arachidonic acid metabolites, including prostaglandins, in the events leading to the acrosome reaction and fertilization.
The aim of the present study was to evaluate the effect of addition of physiologic amounts of different prostaglandins normally present in semen, on sperm motility, on sperm penetration capacity in cervical mucus in vitro, and on the adenosine triphosphate (ATP) concentration in semen. Semen samples were obtained from volunteers who were attending the fertility outpatient clinic. Sperm motility was measured on a video recorder with a built-in timer, sperm penetration by the Kremer test, and ATP by bioluminescence assay. The addition of 19-hydroxy prostaglandin (PG) E to ejaculates positively stimulated sperm motility and sperm penetration capacity. The opposite effect was observed with 19-hydroxy PGF. PGE1, PGE2, and PGF2 alpha had no effect on either parameter, while PGF1 alpha reduced the sperm motility. The addition of 19-hydroxy PGE to ejaculates increased and the addition of 19-hydroxy PGF reduced semen concentrations of ATP. However, only the last-mentioned effect was statistically significant (P less than 0.05). It is suggested that, in particular, 19-hydroxy PGE and 19-hydroxy PGF are important regulators of sperm motility and that the effect may be mediated via effects on the ATP content in the spermatozoa.
These studies were performed to investigate the effects of MeHg on testicular function in Macaca fascicularis monkeys. In an in vivo study involving oral treatment of adult males Macaca fascicularis monkeys with MeHg for 20 weeks, changes in spermatozoal production, motility and morphology and in serum testosterone were followed before, during and after treatment. MeHg treatment significantly decreased % motile spermatozoa and scores for sperm speed and forward progression and increased % abnormal sperm tail forms, at sub-neurotoxic levels. The MeHg-induced increase in semen abnormalities was not accompanied by any significant changes in serum levels of testosterone. No consistent histological abnormalities were detected in testicular biopsies from the treated animals at the end of the treatment period. A good recovery pattern was observed for the MeHg effects on sperm motility while this was unclear for the effects on sperm morphology.
The effect of prostaglandin biosynthesis inhibition has been studied in two groups of infertile oligozoospermic patients with high or normal-low seminal prostaglandin (PG) levels. PGE and 19-OH PGE were assayed by means of a gas chromatographic method and the most important seminal parameters (volume, concentration, motility and morphology of spermatozoa) were evaluated in basal conditions and at the end of indomethacin treatment, at a daily oral dose of 100 mg for thirty days. A drop in prostaglandin levels following indomethacin was observed in both groups of patients but only in the group with high concentrations of prostanoid derivates the prostaglandin inhibition was correlated with a significant improvement in sperm count and motility.
The incorporation of 14C labelled myristic, palmitic, stearic, oleic and linoleic acids in vitro into the lipids of ovine spermatozoa was followed at time intervals from 2 min to 2 hr. Diglycerides readily incorporated fatty acids; 1,2 and 1,3 diglyceride fractions showed preferential specificities for palmitic and myristic acids, respectively, but stearic acid was poorly metabolized by both components. The lower incorporation of acids into total phospholipids reflected the relative metabolic stability of the major phospholipid fractions in ovine spermatozoa, but the minor phospholipids, particularly phosphatidylinositol, showed comparatively high metabolic activity. Compositional analyses, showed that myristic acid was the major component of diglycerides, whereas docosahexaenoic acid was the principal fatty acid of the major phospholipid classes. These findings have been compared with previous work on fatty acid metabolism in bovine spermatozoa.
1.1. The incorporation of [I-14C]myristic, -palmitic, -stearic, -oleic and -linoleic acids in vitro into the lipids of bovine testicular tissues was measured after incubation for 2 hours. Tissue slices from the testes of adult, 4-month and 2-week-old animals were used.2.2. The mature testis incorporated less of each substrate than immature testes, but each tissue incorporated linoleic acid to the greatest extent.3.3. Phosphatidylinositol and diglycerides were metabolically more active than other major phospholipid and neutral lipid fractions in the mature testis, and the metabolism of cholesteryl esters was also significant at this stage.4.4. With the immature testes a more general metabolism was apparent, reflecting the lack of functional specialization in these tissues.5.5. Incorporated linoleic acid was readily desaturated, with maximal desaturase activity occurring in the testis tissue from the 4-month-old calf. Fatty acid incorporations were not related to the endogenous fatty acid concentrations of testis lipids.6.6. The lipid fractions of all tissues contained very little docosapentaenoic acid, but considerable amounts of docosahexaenoic acid, particularly in the ethanolamine phosphoglycerides. Within the phospholipids, docosahexaenoic acid content increased with maturation, whereas arachidonic acid content decreased. PIasmalogenic aldehydes were more saturated in character in the mature testis.
Excerpt
Department of Veterinary Physiology, University of Sydney, N.S. W. 2006, Australia
(Received 3rd May 1974)
Recent work has established the composition of phospholipids and phospholipid-bound fatty acid esters and aldehydes in ram, bull, boar, human and rabbit spermatozoa (Scott, Voglmayr & Setchell, 1967; Pursel & Graham, 1967; Neill & Masters, 1972, 1973; Johnson, Pursel & Gerrits, 1972; Poulos & White, 1973; Poulos, Darin-Bennett & White, 1973; Darin-Bennett, Poulos & White, 1973b). These data led Poulos, Darin-Bennett & White (1973) to suggest that the spermatozoa of these species could be allocated to two groups on the basis of the ratio of the phospholipid-bound polyunsaturated:saturated fatty acids, which could be correlated with sensitivity to cold-shock. Thus, the ratio for the spermatozoa of ram, bull and boar, which are known to be very susceptible to cold-shock, is approximately three times the ratio found for the less sensitive spermatozoa of the rabbit and human
Male Wistar rats were administered single daily doses of 0, 1, 2.5 and 5 mg Hg2+ (as methyl mercuric chloride)/kg po for 7 consecutive days. After dosing was discontinued, 14 sequential mating trials were conducted, each trial consisting of individual males being caged with 2 untreated virgin females for 5 days. A dose-related reduction in mean litter size per pregnancy attributable to preimplantation losses occurred at all doses during days 5–20 of post-treatment. In a long-term experiment, male rats were dosed po daily throughout a maximum of 21 mating trials, each of 5 days duration. From 30 days onward at 1 mg/kg/day and from 90 days onward at 0.5 mg/kg/day, a reduction in average litter size due to preimplantation losses was noted. Such an effect was not observed at 0.1 mg/kg/day. Male rats dosed for 7 days had a dose-related reduction in incidence of fertile matings. This effect was not apparent during chronic treatment. Male mice administered daily doses po of up to 5 mg Hg2+/kg for 5 or 7 consecutive days and then sequentially mated for 5–7 trials produced no postimplantation losses or reduction of fertility. There was an indication of slight reduction in average number of viable embryos possibly resulting from preimplantation loss.
1.1. The phospholipid-bound fatty acids of ram, bull, boar, rabbit and human spermatozoa contained high levels of polyunsaturated fatty acids. Values ranged from 70 per cent by weight of the total fatty acid fraction in the boar to approximately 40 per cent in both human and rabbit.2.2. Docosahexaenoic acid (22:6) was quantitatively the most important fatty acid found in all species except the rabbit.3.3. The major saturated fatty acid found in mammalian spermatozoa was palmitic acid.4.4. The predominant fatty aldehyde was palmitaldehyde (16:0) and values ranged from 91·2 per cent in ram to 51·1 per cent in human spermatozoa.
To determine the effect of a linoleic acid deficiency on the fertilizing capacity of the chicken, White Leghorn males were fed a vitamin-free casein-gelatin basal diet practically devoid of linoleic acid from 4 weeks of age. Corn oil was used as a source of linoleic acid. On the basis of one insemination (0.05 cm³ undiluted semen) per hen per 3-week period, a linoleic acid deficiency significantly decreased the average fertility of males. No differences in fertility were observed between the groups fed the linoleic acid-supplemented diet and a practical diet. There were no differences in percentage of dead germs, pipped eggs, or chicks hatched among the dietary treatments. The fertilizing capacity, as measured by the decline in number of fertilized eggs after a single insemination, indicated that the linoleic acid deficiency resulted in a decrease of fertility below 90% on day 4 after insemination as contrasted with day 9 for the linoleic acid-supplemented diet. Linoleic acid deficiency had no effect on body weight maintenance, feed consumption, semen volume, sperm motility, and sperm count. Fatty acid determinations of semen and blood indicated a much lower value for linoleic acid in the linoleic acid-deficient group than for the supplemented groups. Two fatty acids tentatively identified as docosadienoic and docosatetraenoic were found in semen lipid. The percentages of docosadienoic and docosatetraenoic were 6 times larger and 6 times less, respectively, in the deficient semen than in the nondeficient semen. The significance of these findings remains to be elucidated.
1.1. Of eight species, guinea pig testis had the highest total lipid content (3·4 per cent) and the human had the lowest (1·6 per cent). Phospholipids ranged from 64 to 86 per cent of testicular total lipids in dog, mouse, rat, rabbit, chicken and hamster while guinea pig had 41 per cent and human 56 per cent.2.2. Total fatty acid patterns, especially the twenty-two-carbon polyunsaturated acids, were characteristic for most species. Rat, hamster, rabbit and dog testes had high 22:5 (11–16 per cent) and low 22:6. Mouse and guinea pig had low but similar amounts of these acids. Human testis had 8·5 per cent 22:6 and negligible 22:5. Chicken testis contained 22:4 and no 22:5 or 22:6 acids.3.3. Large variations in amount of dietary linoleic acid had little effect on the polyunsaturated acids of rat testis. Essential fatty acid deficiency or the feeding of only linoleic or linolenic acids produced distinctive fatty acid patterns.
To study the effects of essential fatty acid deficiency upon rabbits, especially upon spermatogenesis, five immature, male, New Zealand rabbits were fed a purified diet devoid of fat for 14 weeks. The fatty acids of the testes showed a marked increase of 5,8,11-eicosatrienoic acid and a decrease in the members of the linoleate family of fatty acids. Gross evidence of essential fatty acid (EFA) deficiency included diminished growth and feed efficiency, and loss of hair. Total lipids, phospho- lipids, and free cholesterol of testes were found to be decreased, whereas triglycérides followed the reverse pattern. No qualitative or quantitative differences in the fatty acid composition of seminal vesicles were found in the deficient and control groups. Testes of deficient animals showed an extensive degenerative change in the seminifer ous tubules; no stage beyond secondary spermatocyte was evident. Glucose 6-phosphate dehydrogenase and A5-3/3-hydroxysteroid dehydrogenase activity of Leydig cells in both groups showed that these enzymes were present. Male accessory gland weights were significantly reduced in the deficient animals, indicating reduced androgen secretion. Histological examination of the anterior pituitary gland showed signs of degenerative changes in PAS-positive basophilic cells, which appeared to be shrunken and partially degranulated in EFA-deficient rabbits, suggesting that EFA deficiency is accompanied by diminished secretion of the anterior pituitary. There was also an increase in the number of chromophobes and a decrease in acidophil cells. These observations suggest that the degeneration of gonads observed during essential fatty acid deficiency may be due to primary impairment of anterior hypophyseal function.