The effect of dietary n-3 polyunsaturated fatty acids supplementation of rams on semen quality and subsequent quality of liquid stored semen

Flaxseed oil modulates testicular biometrics, hormone, libido, antioxidant and semen profiles in endangered Teressa goat of Andaman and Nicobar Islands

Teressa goat is a unique goat breed in Andaman and Nicobar Islands (ANI) of India. Effects of Flaxseed oil (FSO) supplementation in body weight (BW), scrotal circumference (SC), testicular volume (TV) and testicular weight (TW), endocrinological profiles, sex behavioural profiles (SBPs), oxidative stress markers and semen production and its quality profiles in rainy and dry summer season were studied in Teressa goat. Male goats (n = 12) of 3-4 years old were equally divided into control and treated groups. Treated animals received 25 mL FSO per day. Oral drenching of FSO was done in the morning before feeding the concentrate ration. Body weight, scrotal circumference, TV and TW were measured in bucks of FSO treated and untreated during rainy and dry summer seasons. Blood follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), cortisol and prolactin, total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA) were measured in bucks of FSO treated and untreated during rainy and dry summer seasons. Libido score (LS), mating ability score (MAS) and sex behavioural score (SBS) were estimated at time of semen collection in bucks of FSO treated and untreated during rainy and dry summer seasons. Semen samples (n = 100; 50 semen samples from each season; each 25 semen samples from control and treatment groups per season) were collected and analysed for semen quality profiles. One-way ANOVA (control rainy, control dry, treated rainy and treated dry) revealed that BW, SC, TV and TW, FSH, LH, testosterone, TSH, T3 and T4 were higher (P < 0.05) and cortisol and prolactin were lower (P < 0.05) in FSO treated bucks of rainy season followed by untreated bucks of rainy season, FSO treated bucks of dry summer season and were lower (P < 0.05) in untreated bucks of dry summer season. Similarly, TAC, CAT, SOD and GSH, LS, MAS and SBS, and volume, pH, sperm concentration, mass activity, total motility (TM), viability, acrosomal integrity (AcI), plasma membrane integrity (PMI) and nuclear integrity (NI) were higher (P < 0.05) and MDA and TSA were lower (P < 0.05) in FSO treated bucks of rainy season followed by FSO treated bucks of dry summer season, untreated bucks of rainy season and were lower (P < 0.05) in untreated bucks of dry summer season. The results of the present study indicated that the breeding bucks suffered physiological stress (higher cortisol), oxidative stress (higher MDA and deficiency of antioxidants), hormonal imbalance (higher prolactin and cortisol and deficiency of gonadotropins, gonadal hormone and thyroid hormones) and infertility due to poor libido and poor semen production and its quality profiles during dry summer season. Thus, dry summer was more stressful season compared to rainy season for the goat bucks. FSO supplementation mitigated these stresses and improved the scrotal and testicular biometrics, libido, antioxidants, hormones and semen quality profiles in Teressa goat bucks. The current study concluded that FSO effectively improved the hormones, libido, antioxidant profiles, and scrotal and testicular biometrics with cascading beneficial effects on semen quality profiles in Teressa goat bucks under humid tropical island ecosystem of Andaman and Nicobar Islands.

Moringa oleifera leaf ethanolic extract benefits cashmere goat semen quality via improving rumen microbiota and metabolome

Background

Artificial insemination (AI) is an effective reproductive technique to improve the performance of cashmere goats and prevent the spread of diseases, and the quality of the semen determines the success of AI. The potential of Moringa oleifera leaf powder (MOLP) and Moringa oleifera leaf ethanolic extract (MOLE) to improve semen quality has been reported, but the underlying mechanisms remain unclear. For the purpose, 18 mature male cashmere goats were randomly assigned into three groups: the control (CON), MOLP, and MOLE groups. The CON group received distilled water orally; the MOLP group was orally treated with 200 mg/kg body weight (BW) MOLP; and the MOLE group was orally treated with 40 mg/kg BW MOLE.

Results

Results showed that MOLE contained long-chain fatty acids and flavonoids. Treatment with MOLP and MOLE increased the activities of the serum catalase, superoxide dismutase, and glutathione peroxidase (P < 0.05), enhanced the total antioxidant capacity (P < 0.05), and reduced the serum malondialdehyde level (P < 0.05). At the same time, MOLE increased the contents of serum gonadotropin releasing hormone and testosterone (P < 0.05). Moreover, MOLE significantly increased sperm concentration, motility, and viability (P < 0.05). Meanwhile, MOLE raised the Chao1 index (P < 0.05) and altered the composition of the rumen microbiota; it also raised the relative abundance of Treponema (P < 0.05) and Fibrobacter (P < 0.05) and reduced the relative abundance of Prevotella (P < 0.1). Correlation analysis revealed the genus Prevotella was significantly negatively correlated with sperm concentration, as well as sperm motility and viability. Furthermore, MOLE significantly increased the rumen levels of the steroid hormones testosterone and dehydroepiandrosterone (P < 0.05), as well as the polyunsaturated fatty acids (PUFAs) alpha-Linolenic acid, gamma-Linolenic acid, docosapentaenoic acid, and 9-S-Hydroperoxylinoleicacid (P < 0.05).

Conclusions

Oral MOLE supplementation can improve semen quality by increasing the antioxidant capacity and altering the rumen microbiota and metabolites of cashmere goats. Moreover, the MOLP supplementation could enhance the antioxidant capacity of cashmere goats.

"Fine feathers make fine birds" - The mammalian sperm plasma membrane lipid composition and effects on assisted reproduction

The sperm plasma membrane is important in modulating many sperm functions. The sperm membrane is composed of a complex mixture of lipids including phospholipids, glycolipids and sterols. There are differences of sperm membrane composition among mammalian species with two groups differing in the most abundant polyunsaturated fatty acid (PUFA), either docosahexaenoic (ω-3 PUFA) or docosapentaenoic acid (ω-6 PUFA). During testicular and epididymal maturation, composition of the sperm plasma membrane evolves with spermatozoa gaining the capacity for fertilization. The importance of fatty acid metabolism for complete spermatogenesis has been elucidated using gene knockout mice. During epididymal transit cholesterol content decreases and PUFA content increases, conferring more fluidity properties to the sperm membrane. The relatively lesser content of antioxidant enzymes and the relatively larger content of PUFA make the spermatozoa particularly susceptible to lipid peroxidation during sperm preservation. In numerous studies, there was adding of PUFA and antioxidants to the diet of animals or to semen extenders with the aim to improve sperm membrane integrity. This review highlights the current knowledge on the sperm membrane composition and effects on sperm function in mammalian domestic animals.

Combined Effect of Flaxseed Oil and Vitamin E Supplementation During Bull Semen Cryopreservation on Sperm Characteristics

The present study was performed to investigate the effects of supplementing flaxseed oil (FO) or vitamin E (VE) or their combination to an extender for Simmental bull semen cryopreservation. In experiment 1, different concentrations of FO (0, 10, 100, and 1000 ng/mL) and VE (0.05, 0.1, and 0.2 mg/mL) were added to the extenders. In experiment 2, FO, VE, and FO + VE were added and a control group was included. Sperm viability, motility, motion parameters, acrosome integrity and membrane integrity, endogenous antioxidant indices, reactive oxygen species, and malondialdehyde levels were evaluated after semen thawing. A higher percentage of viability, motion parameters, endogenous antioxidant indices, and membrane integrity was observed after supplementation with 10 ng/mL FO or 0.1 mg/mL VE compared with the control group (p < 0.05). Also, combined supplementation of 10 ng/mL FO +0.1 mg/mL VE further improved the quality of frozen-thawed sperm by regulating viability, motion parameters, membrane integrity, and endogenous antioxidant indices compared with the FO or VE alone (p < 0.05). These results indicated that FO (10 ng/mL) + VE (0.1 mg/mL) could further improve the protective effects on bull sperm post-thaw.

Flaxseed Oil as a Source of Omega n-3 Fatty Acids to Improve Semen Quality from Livestock Animals: A Review

Simple Summary

In response to the conservation of threatened livestock species, different strategies to improve semen quality have been developed. However, spermatozoa remain sensitive to cryopreservation damages especially that of avian species, thus limiting the use of reproductive biotechnologies such as artificial insemination in the conservation programs. Improving semen quality through dietary inclusion of long-chain polyunsaturated fatty acids sources mainly omega n-3 has received research interest. This review explains the role of flaxseed oil as a source of omega n-3 fatty acids to improve semen quality. Comprehensive information elaborated in this review is believed to promote the use of flaxseed oil as an alternative source of omega n-3 fatty acids to fish oil. This is because fisheries are over-exploited and could collapse.

Abstract

The demand to conserve indigenous species through the cryo-gene bank is increasing. Spermatozoa remain sensitive to cryopreservation damages especially that of avian species thus limiting the use of reproductive biotechnologies such as artificial insemination in the conservation programs. Long-chain polyunsaturated fatty acid (LCPUFAs), specifically omega n-3, expanded a research interest to improve animal reproductive efficiency through improving spermatozoa quality. This is driven by the fact that mammals cannot synthesize omega-3 de-novo because they lack delta-12 and delta-15 desaturase enzymes thus supplemented in the diet is mandatory. Delta-12 and delta-15 add a double bond at the 12th and 15th carbon-carbon bond from the methyl end of fatty acids, lengthening the chain to 22 carbon molecules. Fish oil is a pioneer source of omega n-3 and n-6 fatty acids. However, there is a report that numerous fisheries are over-exploited and could collapse. Furthermore, processing techniques used for processing by-products could complement alterations of the amino acid profile and reduce protein retrieval. Alternatively, flaxseed oil contains ±52–58% of total fatty acids and lignans in the form of α-linolenic and linoleic acid. Alpha-linolenic acid (ALA,18:3n-3) is enzymatically broken-down de-novo by delta-6 desaturase and lengthened into a long-chain carbon molecule such as eicosapentaenoic acid (C20:5n-3). Nevertheless, controversial findings following the enrichment of diet with flaxseed oil have been reported. Therefore, this paper is aimed to postulate the role of flaxseed oil as an alternative source of omega n-3 and n-6 fatty acids to improve semen quality and quantity from livestock animals. These include the interaction between docosahexaenoic acid (DHA) and spermatogenesis, the interaction between docosahexaenoic acid (DHA) and testicular cells, and the effect of flaxseed oil on semen quality. It additionally assesses the antioxidants to balance the level of PUFAs in the semen.

Effect of feeding linseed diet on testis development, antioxidant capacity, and epididymal cauda sperm concentration in Chinese Hu lamb

Polyunsaturated fatty acids (PUFAs) are essential for mammalian testis development and sperm function. However, PUFAs that are contained in linseed oil are easily oxidized in the diet and biohydrogenated in the rumen. In this study, we investigated the effect of linseed as a source of PUFAs on the antioxidant capacity and testis development in Hu lamb. Seventy-five 3-month-old lambs were randomly assigned to three groups. Within each treatment group, 25 lambs were allocated to five pens (five lambs per pen). The lambs in the control group were fed a control diet without linseed for 42 days from D22 to D63. Group I (BS28) was fed a control diet from D22 to D35 and 8% linseed diet from D36 to D63. Group II (BS42) was fed an 8% linseed diet for 42 days from D22 to D63. After 63-day feeding trial, all lambs except the heaviest and lightest in each pen were humanely slaughtered and investigated. Results revealed that feeding linseed did not affect the body weight, scrotal circumference, and testis weight, whereas feeding linseed for 42 days increased the epididymis weight (37.85 ± 1.61 g vs. 32.09 ± 1.06 g, P < 0.05) compared with the control group. Feeding lambs with linseed for 42 days also significantly upregulated the expression of antioxidative (glutathione peroxidase 4 and copper-zinc superoxide dismutase), steroidogenesis (3β-hydroxysteroid dehydrogenase and steroid acute regulatory protein), and PUFA metabolism-related genes (fatty acid desaturase 2 and elongation of very long-chain fatty acid protein 2) and proliferating cell nuclear antigen mRNA (P < 0.05). It also increased the relative expression of mitochondrial DNA (P < 0.05), total antioxidant capacity (0.230 ± 0.019 mmol/mgprot vs. 0.175 ± 0.011 mmol/mgprot, P < 0.05), and superoxide dismutase (1661.467 ± 147.117 U/mgprot vs. 1158.891 ± 98.850 U/mgprot, P < 0.05) in testicular tissue but decreased the cholesterol concentration (0.331 ± 0.073 mmol/mgprot vs. 0.671 ± 0.092 mmol/mgprot, P < 0.05) compared with the control group. Therefore, feeding lambs with linseed for 42 days stimulated seminiferous tubule development and increased the number of Sertoli cells (20.71 ± 0.89 vs. 17.6 ± 0.73, P < 0.05), epididymal cauda lumina diameter (638.26 ± 22.32 μm vs. 444.41 ± 34.80 μm, P < 0.05), and the number of sperm in the epididymal cauda (68.91 ± 7.06 × 10⁸/g vs. 36.61 ± 7.50 × 10⁸/g). All these results suggested that feeding linseed in the early reproductive development stage of lambs upregulated the expression of antioxidative, steroidogenesis, and PUFA metabolism-related genes; increased the antioxidant capacity in lamb's testis; and contributed to testis development and spermatogenesis.

Effect of dietary supplementation of omega-3 rich oils on seminal characteristics, oxidative stress and plasma testosterone levels in Beetal bucks

The objective of the present study was to evaluate the efficacy of dietary supplementation of omega-3 rich oils, chia seed oil (CSO; Salvia hispanica) and linseed oil (LSO; Linum usitatissimum), on seminal characteristics, and plasma testosterone levels in Beetal bucks. The bucks were fed diet supplemented with either LSO or CSO @1% on dry matter basis or un- supplemented diet for 100 days. Daily intake of omega-3 fatty acids was 0.60 (control diet), 4.04 (diet supplemented with LSO) and 4.57 g (diet supplemented with CSO). Ultrasonography revealed no significant improvement in the testicular size yet the growth rate was much high in animals fed omega-3 supplemented diet. Ejaculate volume, individual motility, viability, sperm concentration, plasma membrane and acrosome integrity were significantly higher in bucks fed CSO supplemented diet as compared to LSO and control diet. The percentage of abnormal spermatozoa was significantly less in bucks fed CSO and LSO diet than control. Melanoaldehyde (MDA, μmole/109 sperm) concentration was lowest in bucks fed CSO diet followed by LSO and control diet. Activity of superoxide dismutase, glutathione reductase and catalase was significantly higher in spermatozoa of bucks fed CSO and LSO diet as compared to control. Bucks fed CSO and LSO supplemented diet had nonsignificantly higher plasma testosterone concentrations than control. These findings indicated that CSO supplementation in the diets may be helpful in improving the process of spermatogenesis, sperm output, quality and fertility of bucks.

Dietary omega-3 fatty acids from linseed oil improve quality of post-thaw but not fresh sperm in Holstein bulls

Docosahexaenoic acid (DHA), a member of the n-3 fatty acid family present in fish oil, has several positive effects on bovine sperm, including membrane integrity, motility and viability, as well as cold sensitivity. Our objective was to investigate effects of varying amounts of omega-3 fatty acids from linseed oil, administered orally, on quality of fresh and frozen-thawed bull sperm. Twenty fertile Holstein bulls (874 ± 45.38 kg) were randomly and equally assigned to four groups and received encapsulated (rumen-protected) fats for 12 weeks, as follows: group P, 300 g palm oil; group Pl, 200 g palm oil + 100 g linseed oil; group pL, 100 g palm oil + 200 g linseed oil; and group L, 300 g linseed oil. Sperm quality of fresh and frozen-thawed semen was evaluated by routine assays including sperm motion characteristics (CASA), membrane integrity (eosin-nigrosin), membrane activity (hypo-osmotic swelling test; HOST) and malondialdehyde (MDA) content. There were no significant differences among groups in semen volume, sperm concentration or sperm quality parameters in fresh semen. However, after freezing-thawing, total and progressive motility in group P (59.61 ± 1.95 and 40.19 ± 2.48%, respectively; LSM ± SEM) were lower (P < 0.05) than in groups Pl (66.06 ± 1.95 and 47.53 ± 2.48%), pL (65.67 ± 1.95 and 47.48 ± 2.48%) and L (65.36 ± 1.95 and 47.62 ± 2.48)%, with no significant differences among the latter three groups. Furthermore, membrane integrity (eosin-nigrosin) and activity (HOST) were lower (P < 0.05) in group P (55.79 ± 2.15 and 42.19 ± 2.17%) compared to groups Pl (62.73 ± 2.15 and 48.93 ± 2.17%), pL (64.06 ± 2.15 and 50.01 ± 2.17%) and L (64.47 ± 2.15 and 49.68 ± 2.17%), with no significant differences among the latter three. Furthermore, there were more (P < 0.05) morphologically abnormal sperm in group P (25.99 ± 1.62%) than in groups Pl, PL and L (21.55 ± 1.62, 21.69 ± 1.62 and 20.90 ± 1.62%). In conclusion, feeding Holstein bulls 100-300 g linseed oil daily improved sperm cryotolerance.

Flaxseed oil modulates semen production and its quality profiles, freezability, testicular biometrics and endocrinological profiles in mithun

Mithun (Bos frontalis) is a unique domestic free range bovine species of North Eastern Hilly (NEH) regions of India. Effect of feed supplementation of Flaxseed oil (FSO) on semen production and its quality profiles, freezability, oxidative stress, apoptotic sperm percentage and subsequently on endocrinological profiles & scrotal and testicular biometrics in different seasons was studied in mithun. The experimental animals were divided into two groups, Gr I: Control (n = 3) and Gr II: Treatment (n = 3; Flaxseed oil @ 150 mL/day). FSO was supplemented through oral drench in the morning hours just before concentrate feeding. A total of 80 semen samples (n = 80; 20 semen samples from each season; each 10 semen samples from control and treatment groups per season) were collected, not more than twice per week in winter, spring, autumn and summer seasons. Semen quality profiles (SQPs) such as volume, sperm concentration, motility (forward progressive and total), motility & velocity profiles by computer assisted sperm analyser (CASA), viability, total sperm abnormality, acrosome integrity, plasma membrane & nuclear abnormality and apoptotic sperm percentage were estimated in fresh semen. Along with SQPs measured in fresh semen, motility in estrus bovine cervical mucus (bovine cervical mucus penetration test; BCMPT) and mitochondrial membrane potential (MMP) by JC-1 stain were determined in the post-thawed semen samples. Biochemical profiles (aspartate aminotransferase; AST, alanine aminotransferase; ALT, total cholesterol; CHO), antioxidant profiles (superoxide dismutase; SOD, catalase; CAT, glutathione; GSH, total antioxidant capacity; TAC) and oxidative stress profile (malondialdehyde; MDA) were estimated in fresh semen whereas AST, ALT, lactate dehydrogenase (LDH), TAC and MDA were estimated in the frozen thawed semen samples. Endocrinological profiles such as follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, cortisol and thyroxin and scrotal circumference (SC) & testicular biometrics were measured in both groups in different seasons. Result revealed a significant (p < 0.05) improvement in motility (total & forward progressive, motility & velocity by CASA and vanguard distance in cervical mucus), viability, intactness of acrosome & plasma membrane, MMP, antioxidant profiles and reduction in total sperm and nuclear abnormalities, reduction in leakage of intracellular enzymes and reduction in oxidative stress profile and reduction of apoptotic sperm percentage were observed in FSO supplemented than in un-supplemented control group accordingly in fresh and post thawed semen samples. Blood FSH, LH, testosterone and thyroxin concentration were significantly (p < 0.05) increased and cortisol concentration was significantly (p < 0.05) decreased in FSO supplemented group than in unsupplemented control group. Similarly, SC and testicular biometrics were increased significantly (p < 0.05) in supplemented than unsupplemented group for different seasons and significantly (p < 0.05) higher in winter and spring than in summer season in the experimental groups. It can be concluded from the study that supplementation of FSO can effectively be utilized to improve the antioxidant profiles, reduction of oxidative stress with cascading beneficial effects on SQPs and fertility status of the mithun bull.

The influence of dietary sunflower oil, rich in n-6 polyunsaturated fatty acids, in combination with vitamin C on ram semen parameters, sperm lipids and fertility

BACKGROUND

Dietary fats, fed to ruminant animals, have been observed to improve reproductive function. Sunflower oil is one of the richest sources of polyunsaturated fatty acids (PUFAs), over 60% of which is linoleic acid (C18:2). With regard to recommendations for increased consumption of PUFAs, special emphasis has been given to the importance of consuming more antioxidants to prevent lipid peroxide formation. This study evaluated the effects of dietary n-6 PUFAs and vitamin C (VC) in rams - in particular, on semen quality, blood metabolites, sperm lipids and overall fertility.

RESULTS

Diets supplemented with SFO and VC increased the proportion of motile sperms and their progressive motility improved (P < 0.01). Rams fed a diet containing SFO had an increased proportion of sperms with normal acrosomes in their semen samples (P < 0.01). The highest levels of lactate dehydrogenase activity (LDH) enzyme were found in control rams (2.60 U mL^-1 ). Feeding SFO significantly affected blood triglyceride and cholesterol concentrations (P < 0.05). Diets containing SFO increased the proportion of C18:2c, C20:4, C20:3 and C22 in the sperm lipid composition (P < 0.05). Semen of SFO and VC-fed rams was more fertile than that of control rams when it was artificially inseminated to ewes.

CONCLUSION

Feeding rams with supplemental SFO and VC increased semen quality and improved fertility rates. © 2019 Society of Chemical Industry.

Review: The effect of nutrition on timing of pubertal onset and subsequent fertility in the bull

The advent of genomic selection has led to increased interest within the cattle breeding industry to market semen from young bulls as early as possible. However, both the quantity and quality of such semen is dictated by the age at which these animals reach puberty. Enhancing early life plane of nutrition of the bull stimulates a complex biochemical interplay involving metabolic and neuroendocrine signalling and culminating in enhanced testicular growth and development and earlier onset of sexual maturation. Recent evidence suggests that an enhanced plane of nutrition leads to an advancement of testicular development in bulls at 18 weeks of age. However, as of yet, much of the neuronal mechanisms regulating these developmental processes remain to be elucidated in the bull. While early life nutrition clearly affects the sexual maturation process in bulls, there is little evidence for latent effects on semen traits post-puberty. Equally the influence of prevailing nutritional status on the fertility of mature bulls is unclear though management practices that result in clinical or even subclinical metabolic disease can undoubtedly impact upon normal sexual function. Dietary supplements enriched with various polyunsaturated fatty acids or fortified with trace elements do not consistently affect reproductive function in the bull, certainly where animals are already adequately nourished. Further insight on how nutrition mediates the biochemical interaction between neuroendocrine and testicular processes will facilitate optimisation of nutritional regimens to optimise sexual maturation and subsequent semen production in bulls.

Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies

BACKGROUND

Infertility is a global public health issue, affecting 15% of all couples of reproductive age. Male factors, including decreased semen quality, are responsible for ~25% of these cases. The dietary pattern, the components of the diet and nutrients have been studied as possible determinants of sperm function and/or fertility.

OBJECTIVE AND RATIONALE

Previous systematic reviews have been made of the few heterogeneous low-quality randomized clinical trials (RCTs) conducted in small samples of participants and investigating the effect of specific nutrients and nutritional supplements on male infertility. However, as yet there has been no systematic review of observational studies.

SEARCH METHODS

A comprehensive systematic review was made of the published literature, from the earliest available online indexing year to November 2016, in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. We have included cross-sectional, case-control and prospective and retrospective studies in which fertile/infertile men were well defined (men with sperm disorders, sperm DNA damage, varicocele or idiopathic infertility). The primary outcomes were semen quality or fecundability. With the data extracted, we evaluated and scored the quality of the studies selected. We excluded RCTs, animal studies, review articles and low-quality studies.

OUTCOMES

A total of 1944 articles were identified, of which 35 were selected for qualitative analysis. Generally, the results indicated that healthy diets rich in some nutrients such as omega-3 fatty acids, some antioxidants (vitamin E, vitamin C, β-carotene, selenium, zinc, cryptoxanthin and lycopene), other vitamins (vitamin D and folate) and low in saturated fatty acids and trans-fatty acids were inversely associated with low semen quality parameters. Fish, shellfish and seafood, poultry, cereals, vegetables and fruits, low-fat dairy and skimmed milk were positively associated with several sperm quality parameters. However, diets rich in processed meat, soy foods, potatoes, full-fat dairy and total dairy products, cheese, coffee, alcohol, sugar-sweetened beverages and sweets have been detrimentally associated with the quality of semen in some studies. As far as fecundability is concerned, a high intake of alcohol, caffeine and red meat and processed meat by males has a negative influence on the chance of pregnancy or fertilization rates in their partners.

WIDER IMPLICATIONS

Male adherence to a healthy diet could improve semen quality and fecundability rates. Since observational studies may prove associations but not causation, the associations summarized in the present review need to be confirmed with large prospective cohort studies and especially with well-designed RCTs.

Polyunsaturated Fatty Acids in Male Ruminant Reproduction - A Review

Fatty acids such as n-3 and n-6 polyunsaturated fatty acids (PUFA) are critical nutrients, used to improve male reproductive performance through modification of fatty acid profile and maintenance of sperm membrane integrity, especially under cold shock or cryopreservation condition. Also, PUFA provide the precursors for prostaglandin synthesis and can modulate the expression patterns of many key enzymes involved in both prostaglandin and steroid metabolism. Many studies carried out on diets supplemented with PUFA have demonstrated their capability to sustain sperm motility, viability and fertility during chilling and freezing as well as improving testis development and spermatogenesis in a variety of livestock species. In addition to the type and quantity of dietary fatty acids, ways of addition of PUFA to diet or semen extender is very crucial as it has different effects on semen quality in male ruminants. Limitation of PUFA added to ruminant ration is due to biohydrogenation by rumen microorganisms, which causes conversion of unsaturated fatty acids to saturated fatty acids, leading to loss of PUFA quantity. Thus, many strategies for protecting PUFA from biohydrogenation in rumen have been developed over the years. This paper reviews four aspects of PUFA in light of previous research including rumen metabolism, biological roles, influence on reproduction, and strategies to use in male ruminants.

Dietary n-6:n-3 ratio and Vitamin E improve motility characteristics in association with membrane properties of boar spermatozoa

This study was aimed to evaluate the effects of dietary n-6:n-3 ratio and Vitamin E on the membrane properties and motility characteristics of spermatozoa in boars. Forty Duroc boars were randomly distributed in a 2 × 2 factorial design with two n-6:n-3 ratios (14.4 and 6.6) and two Vitamin E levels (200 and 400 mg kg⁻¹). During 16 weeks of treatment, fresh semen was collected at weeks 0, 8, 12, and 16 for measurements of motility characteristics, contents of fatty acids, membrane properties (membrane fluidity and membrane integrity), and lipid peroxidation of the spermatozoa. The semen was diluted in Beltsville Thawing Solution (BTS) extender and stored at 17°C, and the sperm motility was assessed at 12, 36, 72, and 120 h of storage. The 6.6 n-6:n-3 dietary ratio increased the contents of n-3 polyunsaturated fatty acids (PUFAs) and docosahexaenoic acid (DHA) and improved the membrane integrity and membrane fluidity of the spermatozoa, resulting in notably increased total motility, sperm progressive motility, and velocity parameters of fresh semen. Feeding diet with Vitamin E (400 mg kg⁻¹) prevented sperm lipid peroxidation, and resulted in higher total motility and sperm progressive motility in fresh and liquid stored semen. In conclusion, the adjustment of n-6:n-3 ratio (6.6) and supply of Vitamin E (400 mg kg⁻¹) successfully improved sperm motility characteristics and thus may be beneficial to the fertility of boars, which might be due to the modification of the physical and functional properties of spermatozoa membrane in response to dietary supplementation.

In vitro addition of docosahexaenoic acid improves the quality of cooled but not frozen-thawed stallion semen

The aim of the present study was to assess the effect of the addition of docosahexaenoic acid (DHA) on the in vitro quality of cooled and frozen-thawed stallion semen. In Experiment 1, semen from 10 stallions was collected (three ejaculates per stallion). Semen was diluted to 100×10⁶ spermatozoa mL^-1 with 0.02mM vitamin E (VE) and 0, 1, 10 or 20ng mL^-1 DHA and frozen. Semen was thawed and total motility (TM), rapid progressive motility (PM), acrosome integrity, membrane fluidity and morphology were assessed. In Experiment 2, semen from three stallions was collected (three ejaculates per stallion) and frozen as in Experiment 1, but VE and DHA were added after thawing. TM and PM were assessed at 30, 60 and 120min and viability, acrosome integrity and membrane fluidity were evaluated at 30min. In Experiment 3, semen from five stallions was collected (one to three ejaculates per stallion), diluted to 20×10⁶ spermatozoa mL^-1 and stored at 4°C. After 1, 24, 48 and 72h, TM, PM, viability, membrane fluidity and lipid peroxidation were assessed. The addition of DHA had no effect on frozen semen (Experiments 1 and 2) but improved TM, PM and membrane fluidity in cooled stallion semen.

Effects of supplemental conjugated linoleic acids (CLA) on fresh and post-thaw sperm quality of Holstein bulls

This study was designed to investigate the effects of feeding-protected conjugated linoleic acid (CLA) on the semen production and sperm freezability in Holstein bulls. Twelve bulls were randomly assigned to two groups (n = 6 per group). Bulls received the normal diet (control group) or the normal diet top-dressed with 50 g of CLA (treated group) for 10 weeks. The control group received 40 g/day calcium soap of fatty acid. Fresh and post-thaw semen quality was assessed on ejaculates collected at the 0, 4, 6, 8 and 10 week of supplementation. Semen evaluations including sperm concentration, motion characteristics (subjective and computer-assisted), viability (Eosin-Nigrosin), membrane integrity (hypo-osmotic swelling test) and abnormality were conducted. Semen volume, sperm concentration and total sperm output were not affected by dietary treatment (p > .05). The proportion of spermatozoa with abnormal morphology in fresh semen significantly increased (p < .05) in the CLA-fed group compared to control group. Also, in CLA-fed group, the proportion of post-thaw spermatozoa with abnormal morphology at week 10 of trial was significantly higher in CLA than control group (p < .05). Progressive motility tended to be increased in the CLA-fed group, although dietary supplementation did not affect other CASA parameters or viability in fresh and frozen-thawed sperm. In this study, CLA supplementation had little positive effect on fresh or post-thaw sperm quality of Holstein bulls.

Effect of docosahexanoic acid on quality of frozen–thawed bull semen in BioXcell extender

This study was conducted to investigate the effect of docosahexanoic acid (DHA) supplementation in BioXcell extender on the quality of frozen–thawed bull semen. Twenty-four ejaculates were collected from three bulls (eight from each bull). Ejaculates with motility ≥70% and normal morphology ≥80% were extended into BioXcell extender to which 0 (control), 3, 5, 10 or 15 ng mL–1 DHA was added. The supplemented semen samples were incubated at 37°C for 15 min for DHA uptake by spermatozoa. Later, samples were cooled for 2 h at 5°C and packaged into 0.25-mL straws, frozen in liquid nitrogen for 24 h and subsequently thawed for evaluation. Results are presented as percentages ± s.e.m. Supplementation with DHA at 3 ng mL–1 significantly improved sperm functional parameters including sperm motility, normal morphology, viability, acrosome integrity and membrane integrity when compared with other supplemented groups and the control. Lipid peroxidation increased as the incorporation of DHA supplementation increased. In conclusion, 3 ng mL–1 concentration of DHA resulted in superior quality of frozen–thawed bull spermatozoa and is suggested as the optimum level of DHA to be added into BioXcell extender.

Effect of dietary fish oil with or without vitamin E supplementation on fresh and cryopreserved ovine sperm

This study was carried out to determine whether dietary fish oil (FO) with or without vitamin E (VE) supplementation would have a beneficial effect on characteristics of fresh and cryopreserved ovine sperm. Sixteen rams were allotted to four groups and fed one of the four diets: control diet (CON; without FO and VE supplementation), VE diet supplying 200 IU VE/day.ram, FO diet containing 2.5% (dry matter basis) FO, and OVE diet containing FO and VE. Semen samples were collected at Weeks 7, 9 and 11 for evaluation of seminal quality. Frozen samples from Weeks 9 and 11 were subjected to computer-assisted semen analysis (CASA). Seminal volume, percentage of sperm with normal morphology and intact acrosome and seminal concentration of malondialdehyde were increased in FO rams (P < 0.05). In VE rams, semen volume and percentage of morphologically normal sperm were higher compared with CON rams; however, in OVE rams these attributes were not different from those in CON rams. Other traits in fresh semen were not affected by the diet. Fish oil alone negatively affected the sperm viability, but not motility, of the frozen–thawed semen; however, simultaneous supplementation with FO and VE resulted in increased percentage of morphologically normal sperm, motility, and viability. The percentages of CASA type A (showing rapid progressive motility) and type B (showing medium progressive motility) sperm were higher in OVE compared with other groups. Vitamin E supplementation decreased the beat-cross frequency values compared with other groups. Other CASA parameters were not affected by the diets. In conclusion, dietary FO and VE in the breeding season of ram, generally, do not cause significant changes in fresh sperm quality but, for cryopreservation of sperm, supplementation of the diet with an antioxidant such as VE may be beneficial when polyunsaturated fatty acids are added to the diet.

The effect of dietary supplementation of algae rich in docosahexaenoic acid on boar fertility

The objective of this study was to assess the effects of dietary supplementation of a commercial algal product rich in docosahexaenoic acid (DHA) on boar fertility as assessed in vitro and in vivo. Boars were fed one of three experimental diets for 19 weeks: (i) Control (Ctl) diet (n = 31), (ii) Ctl diet plus 75g All-G-Rich per day (n = 31) or (iii) Ctl diet plus 150g All-G-Rich per day (n = 30). Parameters assessed were (i) raw semen quality; volume, sperm concentration, total motility and morphology (ii) liquid semen quality; progressive motility, viability, hypotonic resistance and acrosomal integrity (iii) frozen-thawed semen quality; motility, thermal stress, viability, membrane fluidity and mitochondrial activity (iv) sperm and seminal plasma (SP) fatty acid composition (FAC) (v) total antioxidant capacity (TAC) of SP and (vi) farrowing rates and litter sizes of sows (n = 1158) inseminated with liquid semen. Boars consuming 75g All-G-Rich had a larger semen volume (P < 0.05) and a higher total sperm number (P < 0.01) than the Ctl treatment, however, there was no effect of treatment on any other semen quality parameter (P > 0.05). There was no effect of dietary treatment on the FAC and TAC of SP or on farrowing rate and litter size (P > 0.05). There was an effect of dietary treatment on the FAC of sperm, represented by an 1.72 and 1.60 fold increase in the DHA content for 75 and 150g treatments, respectively, compared to the Ctl treatment. In conclusion, a significant increase in semen volume and total sperm number in boars supplemented 75g All-G-Rich daily, resulted in an increase in production of 3 to 4 more doses per ejaculate, thus, indicating that the feeding regime described within this study has the potential for increasing the output of boar studs.

Dietary supplementation with docosahexaenoic acid (DHA) improves seminal antioxidant status and decreases sperm DNA fragmentation

The purpose of this study was to evaluate the effect of docosahexaenoic acid (DHA) dietary supplementation on semen quality, fatty acid composition, antioxidant capacity, and DNA fragmentation. In this randomized, double blind, placebo-controlled, parallel-group study, 74 subjects were recruited and randomly assigned to either the placebo group (n=32) or to the DHA group (n=42) to consume three 500-mg capsules of oil per day over 10 weeks. The placebo group received 1,500 mg/day of sunflower oil and the DHA group 1,500 mg/day of DHA-enriched oil. Seminal parameters (semen volume, sperm concentration, motility, morphology, and vitality), total antioxidant capacity, deoxyribonucleic acid fragmentation, and lipid composition were evaluated prior to the treatment and after 10 weeks. Finally, 57 subjects were included in the study with 25 in the placebo group and 32 in the DHA group. No differences were found in traditional sperm parameters or lipid composition of the sperm membrane after treatment. However, an increase in DHA and Omega-3 fatty acid content in seminal plasma, an improvement in antioxidant status, and a reduction in the percentage of spermatozoa with deoxyribonucleic acid damage were observed in the DHA group after 10 weeks of treatment.

Effect of omega-3 and omega-6 polyunsaturated fatty acid enriched diet on plasma IGF-1 and testosterone concentration, puberty and semen quality in male buffalo

The objective of the present study was to evaluate the effect of omega-3 and omega-6 PUFA enriched diet on plasma IGF-1 and testosterone concentrations, puberty, sperm fatty acid profile and semen quality in male buffalo. Eighteen male buffalo calves were distributed randomly in three different groups and fed concentrate mixture along with green fodder and wheat straw in 50:40:10 ratios as per requirements. Basis ration of animals in group I was supplemented with 4% of prilled fat (PFA), while in group II and group III were added 4.67% of Calcium salt from Soybean (CaSFA) and Linseed oil (CaLFA), respectively. Male buffalo fed omega-3 PUFA high diet significantly increased concentrations of IGF-1 and testosterone in plasma as compared to two other diets (p<0.05). The age of puberty and scrotal circumference significantly increased by dietary fat effect (p<0.05) of which n-3 PUFA enriched diet (CaLFA) had the largest influence as compared to other diets (PFA and CaSFA). Feeding of n-3 PUFA rich diet significantly increased the DHA (C22:6n-3) content in sperm (p<0.05), which contributed to increased fluidity of plasma membrane, elevated quality of sperm (motility, viability) and in vitro fertility (plasma membrane integrity, acrosome integrity) in both fresh and post-thawing semen. These findings indicate that feeding of n-3 PUFA enriched diet increased IGF-1 and testosterone secretion, reduced pubertal age and improved both fresh and post-thawing semen quality in male buffalo.

Effect of supplementation of feed with Flaxseed (Linumusitatisimum) oil on libido and semen quality of Nilli-Ravi buffalo bulls

Background

The current study was designed to investigate the effect of supplementation of Flaxseed (Linumusitatisimum) oil on libido and semen quality of Nilli-Ravi buffalo bulls.

Methods

In this study, 12 adult healthy bulls kept at the Semen Production Unit, Qadirabad district Sahiwal, were used. These bulls were divided into three equal groups, A, B and C. Group A was kept as control, while in groups B and C supplementation of feed was provided by using flaxseed oil @125 ml/day and 250 ml/day,respectively for 12 weeks. Two ejaculates per animal were collected at 0 day then 5th, 6th, 7th, 8th, 9th, 10th, 11th and 12th week of treatment. In this way a total 216 samples were taken, and each semen sample was evaluated for color, volume, mass activity, percent motility, sperm cell concentration per ml, percentage of live sperm, and plasma membrane integrity. Libido of bulls was also evaluated before every collection.

Results

Analysis of data revealed that these parameters were significantly (P < 0.01) increased in flax oil treated animals as compared to control.

Conclusion

It was concluded from the present study that flax seed oil has beneficial effects on reproductive health of buffalo bull.

Fatty acid composition of spermatozoa is associated with BMI and with semen quality

High body mass index (BMI) is negatively associated with semen quality. In addition, the composition of fatty acids of spermatozoa has been shown to be important for their function. The aim of the study was to examine the association between BMI and the composition of spermatozoa fatty acids in men spanning a broad BMI range. We also analysed the relation between fatty acid composition of spermatozoa and semen characteristics, and the relationship between serum fatty acids and spermatozoa fatty acids. One hundred forty-four men with unknown fertility status were recruited from the general population, from couples with identified female infertility and from morbid obesity centres. Standard semen analysis (WHO) and sperm DNA integrity (DFI) analysis were performed. Fatty acid compositions were assessed by gas chromatography. When adjusted for possible confounders, BMI was negatively associated with levels of sperm docosahexaenoic acid (DHA) (p < 0.001) and palmitic acid (p < 0.001). The amount of sperm DHA correlated positively with total sperm count (r = 0.482), sperm concentration (r = 0.469), sperm vitality (r = 0.354), progressive sperm motility (r = 0.431) and normal sperm morphology (r = 0.265). A negative association was seen between DHA levels and DNA fragmentation index (r = -0.247). Levels of spermatozoa palmitic acid correlated positively with total sperm count (r = 0.227), while levels of linoleic acid correlated negatively (r = -0.254). When adjusted for possible confounders, only the levels of arachidonic acid showed positive correlation between spermatozoa and serum phospholipids (r = 0.262). Changes in the fatty acid composition of spermatozoa could be one of the mechanisms underlying the negative association between BMI and semen quality. The relationship between fatty acids of spermatozoa and serum phospholipids was minor, which indicates that BMI affects fatty acid composition of spermatozoa through regulation of fatty acid metabolism in the testis. The role of dietary intake of fatty acids on the spermatozoa fatty acid composition remains to be elucidated.

Dietary fatty acids affect semen quality: a review

Mammalian spermatozoa are characterized by a high proportion of polyunsaturated fatty acids (PUFA) which play a crucial role in fertilization. This review focuses on analysis of sperm fatty acid profiles and the effects of omega-3, saturated and trans dietary and sperm fatty acids on sperm parameters. Two major points have been pivotal points of investigation in the field of sperm fatty acid profiles: first, the comparison between fatty acid profiles of fertile and infertile men and second, the effect of dietary fatty acids on sperm fatty acid profiles as well as sperm quality and quantity. Docosahexaenoic acid (DHA, C22:6n-3), and palmitic acid (C16:0) are the predominant PUFA and saturated fatty acids, respectively, in human sperm cells. Higher levels of DHA are concentrated on the sperm's head or tail varying among different species. However, the human sperm head contains a higher concentration of DHA. Dietary fatty acids influence on sperm fatty acid profiles and it seems that sperm fatty acid profiles are most sensitive to dietary omega-3 PUFA. Although improvements in sperm parameters are a response to omega-3 sources after more than 4 weeks of supplementation in the male diet, time-dependent and dose-dependent responses may explain the failure in some experiments. In human spermatozoa, elevated saturated or trans fatty acid concentration and a low DHA level is a concern. The regulations of the sperm fatty acid mean melting point as well as expression regulation of peroxisome proliferator-activated receptor gamma (PPARG) alongside with spermatozoon assembly, anti-apoptosis effects, eicosanoid formation, and hormone activity are the putative key factors that induce a response by inclusion of omega-3 PUFA.