Dietary supplementation with linseed oil improves semen quality, reproductive hormone, gene and protein expression related to testosterone synthesis in aging layer breeder roosters

Dietary composition influences sperm quality and testis damage via endoplasmic reticulum stress in lambs

BACKGROUND

The metabolic impacts of including soya meal, wheat gluten and corn gluten in the diet of male lambs could influence their reproductive performance.

OBJECTIVES

An experiment was carried out to assess the effects of corn gluten, wheat gluten and soya meal on the reproductive system of male lambs.

METHODS

Twenty-four male Morkaraman lambs, aged 9 months, were utilized in this study and were fed experimental diets for 56 days. The lambs were divided into a control group (soybean meal + safflower meal), a corn group (corn gluten) and a wheat group (wheat gluten).

RESULTS

The serum follicle-stimulating hormone level of the control group was significantly higher and tumour necrosis factor-alpha (TNF-α) level was lower than the wheat and corn gluten groups (p < 0.05). The lowest malondialdehyde level in testicular tissue was observed in the control group, whereas the highest was in the wheat gluten group (p < 0.05). The glutathione level in the control group was significantly higher than in the other groups (p < 0.05). The corn gluten group showed the highest CHOP and IRE1 levels; the lowest Bcl-2 levels and the highest IL-1B and P2 × 7R levels were found in the wheat group; and the lowest TNF-α levels were in the control group (p < 0.05). Additionally, the study revealed that diet had a significant impact on spermatological parameters of the testis such as diameter, volume and weight (p < 0.05).

CONCLUSIONS

These results concluded that the inclusion of different protein sources in the diet of reproductive male lambs affects the metabolism of testicular tissue.

Novel underlying genetic markers for asthenozoospermia due to abnormal spermatogenesis and reproductive organ inflammation

Asthenozoospermia, a male fertility disorder, has a complex and multifactorial etiology. Moreover, the effectiveness of different treatments for asthenozoospermia remains uncertain. Hence, by using bioinformatics techniques, the present study aimed to determine the underlying genetic markers and pathogenetic mechanisms associated with asthenozoospermia due to abnormal spermatogenesis and inflammation of the reproductive tract. GSE160749 dataset was downloaded from the Gene Expression Omnibus database, and the data were filtered to obtain 1336 differentially expressed genes (DEGs) associated with asthenozoospermia. These DEGs were intersected with the epithelial mesenchymal transition datasets to yield 61 candidate DEGs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed, and the results revealed that these candidate DEGs were significantly enriched in the enzyme-linked receptor pathway and the thyroid hormone pathway. A protein-protein interaction network was constructed to identify the key genes of asthenozoospermia. A total of five key genes were identified, among which SOX9 was significantly upregulated, while HSPA4, SMAD2, HIF1A and GSK3B were significantly downregulated. These findings were validated by conducting reverse transcription-quantitative PCR for clinical semen samples. To determine the underlying molecular mechanisms, a regulatory network of transcription factors and miRNA-mRNA interactions was predicted. The expression levels of HSPA4, SMAD2 and GSK3B were positively associated with several related etiological genes of asthenozoospermia. In total, five key genes were closely associated with the level and type of immune cells; higher levels of activated B cells and CD8 T cells were observed in asthenozoospermia. Thus, the findings of the present study may provide clues to determine the underlying novel diagnostic genetic markers and treatment strategies for asthenozoospermia.

α-Linolenic acid-regulated testosterone biosynthesis via activation of the JNK-SF-1 signaling pathway in primary rooster Leydig cells

As a functional fatty acid, α-linolenic acid (ALA) is essential in promoting animal testosterone biosynthesis. This study investigated the effects of ALA on testosterone biosynthesis and the possible mechanism underlying the signaling pathway in primary Leydig cells of the rooster.

METHODS

Primary rooster Leydig cells were treated with ALA (0, 20, 40, or 80 μmol/L) or pretreated with a p38 inhibitor (50 μmol/L), a c-Jun NH2-terminal kinase (JNK) inhibitor (20 μmol/L), or an extracellular signal-regulated kinase (ERK) inhibitor (20 μmol/L) before ALA treatment. Testosterone content in the conditioned culture medium was detected using an enzyme-linked immunosorbent assay (ELISA). The expression of steroidogenic enzymes and JNK-SF-1 signaling pathway factors was detected using real-time fluorescence quantitative PCR (qRT-PCR).

RESULTS

Supplementation with ALA significantly increased testosterone secretion within culture media (P < 0.05), and the optimized dose was 40 μmol/L. Compared with the control group, steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc), and 3β-hydroxysteroid dehydrogenase (3β-HSD) mRNA expression significantly increased (P < 0.05) in the 40 μmol/L ALA group; 17-hydroxylase/c17-20 lyase (P450c17) and p38 mRNA expressions were not significantly different in the 40 μmol/L ALA group; ERK and JNK mRNA expressions were significantly upregulated (P < 0.05) in 40 μmol/L ALA group. In the inhibitor group, testosterone levels were significantly downregulated (P < 0.05). Compared with the 40 μmol/L ALA group, StAR, P450scc, and P450c17 mRNA expressions were significantly decreased (P < 0.05), and 3β-HSD mRNA expression in the p38 inhibitor group did not change; StAR, P450scc, and 3β-HSD mRNA expressions were significantly decreased (P < 0.05), and P450c17 mRNA expression in ERK inhibitor group did not change; StAR, P450scc, 3β-HSD, and P450c17 mRNA expressions were significantly decreased (P < 0.05) in JNK inhibitor group. Additionally, the increased steroidogenic factor 1 (SF-1) gene expression levels induced by ALA were reversed when the cells were pre-incubated with JNK and ERK inhibitors. The levels in the JNK inhibitor group were significantly lower than those in the control group (P < 0.05).

CONCLUSION

ALA may promote testosterone biosynthesis by activating the JNK-SF-1 signaling pathway to upregulate StAR, P450scc, 3β-HSD, and P450c17 expression in primary rooster Leydig cells.

Can Dietary n-3 Polyunsaturated Fatty Acids Affect Apelin and Resolvin in Testis and Sperm of Male Rabbits?

Apelin and other novel adipokines have been associated with normal and pathological reproductive conditions in humans and animals. In this paper, we used a rabbit model to investigate if apelin and resolvin (RvD1) in testis and sperm are associated with the oxidative status of semen and serum testosterone of rabbits fed different diets enriched with flaxseed (alpha-linolenic acid, ALA) or with fish oil (eicosapentaenoic acid, EPA, docosapentaenoic acid, DPAn-3, and docosahexaenoic acid, DHA). Apelin and RvD1 were detected by ELISA and apelin and the apelin receptor by immunofluorescence. Increased levels of apelin in testes from both enriched diets were shown, particularly in the interstitial tissue of the FLAX group. The FLAX diet enhanced serum testosterone, and both enriched diets showed higher levels of malondialdehyde and RvD1 in the testis. In ejaculated sperm, apelin and its receptor were localized in the entire tail of the control and both treated groups. The ryanodine receptor was investigated in rabbit testis; the fluorescent signal was increased in mature elongated spermatids of the FLAX group. In conclusion, this data seems to indicate that FLAX increases the amount of apelin in testis, suggesting an involvement of this adipokine in male reproduction and probably a role in the resolution of the inflammatory status.

Metabolomics and Proteomics Characterizing Hepatic Reactions to Dietary Linseed Oil in Duck

The imbalance in polyunsaturated fatty acid (PUFA) composition in human food is ubiquitous and closely related to obesity and cardiovascular diseases. The development of n-3 PUFA-enriched poultry products is of great significance for optimizing fatty acid composition. This study aimed to improve our understanding of the effects of dietary linseed oil on hepatic metabolism using untargeted metabolomics and 4D label-free proteome analysis. A total of 91 metabolites and 63 proteins showed differences in abundance in duck livers between the high linseed oil and control groups. Pathway analysis revealed that the biosynthesis of unsaturated fatty acids, linoleic acid, glycerophospholipid, and pyrimidine metabolisms were significantly enriched in ducks fed with linseed oil. Meanwhile, dietary linseed oil changed liver fatty acid composition, which was reflected in the increase in the abundance of downstream metabolites, such as α-linolenic acid (ALA; 18:3n-3) as a substrate, including n-3 PUFA and its related glycerophospholipids, and a decrease in downstream n-6 PUFA synthesis using linoleic acid (LA; 18:2n-6) as a substrate. Moreover, the anabolism of PUFA in duck livers showed substrate-dependent effects, and the expression of related proteins in the process of fatty acid anabolism, such as FADS2, LPIN2, and PLA2G4A, were significantly regulated by linseed oil. Collectively, our work highlights the ALA substrate dependence during n-3 PUFA synthesis in duck livers. The present study expands our knowledge of the process products of PUFA metabolism and provides some potential biomarkers for liver health.

Natural Astaxanthin Improves Testosterone Synthesis and Sperm Mitochondrial Function in Aging Roosters

Spermatogenesis, sperm motility, and apoptosis are dependent on the regulation of glandular hormones and mitochondria. Natural astaxanthin (ASTA) has antioxidant, anti-inflammatory, and anti-apoptotic properties. The present study evaluates the effects of ASTA on testosterone synthesis and mitochondrial function in aging roosters. Jinghong No. 1 layer breeder roosters (n = 96, 53-week old) were fed a corn−soybean meal basal diet containing 0, 25, 50, or 100 mg/kg ASTA for 6 weeks. The levels of plasma reproductive hormones and the mRNA and protein levels of molecules related to testosterone synthesis were significantly improved (p < 0.05) in the testes of the ASTA group roosters. In addition, antioxidant activities and free radical scavenging abilities in roosters of the ASTA groups were higher than those of the control group (p < 0.05). Mitochondrial electron transport chain complexes activities and mitochondrial membrane potential in sperm increased linearly with dietary ASTA supplementation (p < 0.05). The levels of reactive oxygen species and apoptosis factors decreased in roosters of the ASTA groups (p < 0.05). Collectively, these results suggest that dietary ASTA may improve testosterone levels and reduce sperm apoptosis, which may be related to the upregulation of the testosterone synthesis pathway and the enhancement of mitochondrial function in aging roosters.

Research Note: Dietary supplementation with pyrroloquinoline quinone disodium (PQQ.Na2) improves oxidative status and semen quality in aging layer breeder roosters

As the antioxidant capacity of sperm declines with age in roosters, the objective of the present study was to determine the effects of different levels of pyrroloquinoline quinone disodium (PQQ.Na₂) on antioxidative and sperm quality parameters of aging layer breeder roosters. A total of ninety-six 63-wk-old Jinghong No. 1 layer breeder roosters were randomly assigned to 4 treatments (0, 0.5, 1, 2 mg/kg PQQ.Na₂) for 6 wk. Antioxidant activity and semen parameters were assessed biweekly. The dietary administration of PQQ.Na₂ significantly increased semen quality (semen volume, sperm motility, straightness, progressive motility, curvilinear velocity, straight-line velocity, and amplitude of lateral head displacement) and antioxidant capacity (T-SOD, GSH-Px, hydroxyl radical scavenging ability, and/or superoxide scavenging capacity) in seminal plasma in aging layer breeder roosters. Whereas, PQQ.Na₂ supplementations significantly decreased malondialdehyde (MDA) concentration in seminal plasma in aging layer breeder roosters. Supplementation with 1 mg/kg dietary PQQ.Na₂ as an antioxidant supplement could increase sperm quality and antioxidant activity of aging layer breeder roosters, while a higher dose (2 mg/kg) did not result in further increment.

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.

Natural astaxanthin enhanced antioxidant capacity and improved semen quality through the MAPK/Nrf2 pathway in aging layer breeder roosters

Background

Natural astaxanthin (ASTA) has strong antioxidant properties and has been widely used as a health product to improve human health. However, the effects of ASTA on the reproductive performance of aging roosters have been poorly studied. We aimed to investigate the effects of dietary ASTA on semen quality and antioxidant capacity in aging roosters and to explore the potential mechanism of semen quality change via anti-oxidation defense system.

Methods

In the present study, 96 53-week-old Jinghong No. 1 layer breeder roosters were fed a corn-soybean meal basal diet containing 0, 25, 50, or 100 mg/kg ASTA for 6 weeks.

Results

Semen quality in the ASTA groups remarkably improved than that in the control group, and antioxidant activities, the abilities to scavenge hydroxyl radicals and superoxide anions, increased gradually with ASTA addition (P < 0.05). In addition, the mRNA levels of antioxidant enzymes as well as the mRNA and protein levels of the mitogen-activated protein kinase (MAPK) and nuclear factor-erythroid 2-related factor 2 (Nrf2) were markedly increased in the 50–100 mg/kg ASTA group (P < 0.05).

Conclusions

Collectively, these results demonstrate that dietary ASTA may improve semen quality by increasing antioxidant enzyme activities and the ability to scavenge hydroxyl radicals, which may be related to upregulation of the MAPK/Nrf2 pathway.

Prolonging photoperiod promotes testosterone synthesis of Leydig cells by directly targeting local melatonin system in rooster testes

The study investigated the effects of prolonging photoperiod on the synthesis of testosterone and melatonin in roosters, and the effect of melatonin on testosterone synthesis in rooster Leydig cells as well as its molecular mechanisms. We randomly divided one hundred and twenty 20-week-old roosters into three groups and provided 6, 12.5 and 16 h light, respectively. The results showed that prolonging photoperiod promoted testosterone synthesis, decreased melatonin production, and inhibited the expression of melatonin membrane receptors MEL1A, MEL1B, MEL1C, and aralkylamine n-acetyltransferase (AANAT) in rooster testes. Subsequently, rooster Leydig cells were isolated and treated with 0, 0.1, 1, 10, and 100 ng/mL melatonin for 36 h. The results suggested that melatonin inhibited testosterone synthesis in rooster Leydig cells, and silencing MEL1A and MEL1B relieved the inhibition of melatonin on testosterone synthesis. Additionally, melatonin reduced the intracellular cyclic adenosine monophosphate (cAMP) level and the phosphorylation level of cAMP-response element binding protein (CREB), and CREB overexpression alleviated the inhibition of melatonin on testosterone synthesis. Furthermore, pretreatment with cAMP activator forskolin or protein kinase A (PKA) activator 8-bromo-cAMP blocked the inhibition of melatonin on CREB phosphorylation and testosterone synthesis. These results indicated that prolonging photoperiod promoted testosterone synthesis associated with the decrease in melatonin production and membrane receptors and biosynthetic enzyme of melatonin in rooster testes, and melatonin inhibited testosterone synthesis of rooster Leydig cells by inhibiting the cAMP/PKA/CREB pathway via MEL1A and MEL1B. This may be evidence that prolonging photoperiod could promote testosterone synthesis through the inhibition of the local melatonin pathway in rooster testes.

Effects of Gossypium spp., Balanites aegyptiaca, and Sesamum indicum seeds oils on quality of chilled and frozen-thawed ram semen

Background and Aim:

Essential oils found frequently in plants are well known for their activities against bacteria, viruses, and fungi, and antioxidant properties. This study aimed to analyze egg yolk replacement by seed oils of Gossypium spp. (cotton), Balanites aegyptiaca (desert date), and Sesamum indicum (sesame) in semen extender, on ram sperm quality chilled at 4°C and frozen-thawed.

Materials and Methods:

Ejaculates were collected from adult rams and refrigerated at 4°C in a Tris-based extender containing 1.25%, 2.5%, 5%, and 10% of Gossypium spp., B. aegyptiaca, and S. indicum seed oils, to evaluate which were the two best extenders for comparison with BIOXcell, a commercial extender for deep freezing ram semen.

Results:

The data showed that sperm movements analyzed by the CASA system were faster in extenders supplemented with 2.5-5% of cottonseed oil and 1.25-10% of sesame oil, whereas in the extender containing B. aegyptiaca oil, all seminal parameters studied had the worst values. During the sperm-freezing process, 5% of cottonseed oil and 5% sesame seed oil were selected from the first study, with sesame oil reaching the best sperm quality. Thus, sperm motility and velocity were 44.14±13.99%, 24.44±12.6%, and 25.92±11.50%; and 20.26±9.56%, 8.76±6.38%, and 9.42±5.40%, respectively, for sesame oil, cottonseed oil, and BIOXcell.

Conclusion:

In summary, 2.5-10% of cottonseed oil and 1.25-10% of sesame seed oil can replace egg yolk in a Tris–egg yolk–based extender. Moreover, a Tris-based extender supplemented with 5% sesame seed oil could be an alternative for deep freezing ram semen, even though these results need to be confirmed with semen collected from rams with appropriate sexual rest.

Dietary supplementation of pumpkin seed oil and sunflower oil along with vitamin E improves sperm characteristics and reproductive hormones in roosters

This study evaluates the effects of pumpkin seed oil and sunflower oil along with vitamin E on the reproductive characteristics of aged roosters. Thirty Ross breeder roosters (45-wk-old) were assigned into 6 groups (5 birds/group) with the following diets: 1) control group (basal diet), 2) basal diet with 2% pumpkin seed oil as omega-3 fatty acid (PSO group), 3) basal diet with 2% sunflower oil as omega-6 fatty acid (SFO group), 4) basal diet with 200 mg/kg vitamin E (Control + vitE group), 5) basal diet and 2% pumpkin seed oil along with 200 mg/kg vitamin E (PSO + vitE group) and 6) basal diet and 2% sunflower oil along with 200 mg/kg vitamin E (SFO + vitE group). Roosters were fed on the experimental diets for 60 d and different characteristics of sperm characteristics including routine semen analysis and several sperm functional tests in every 20 d were examined. Reproductive hormones were also evaluated in 0 d and at the end of the trial. Semen volume and morphology were not affected by any of the diets. The roosters fed with pumpkin seed oil + vitE showed the higher percentage of sperm concentration, total motility, progressive motility, viability and membrane integrity and the lower lipid peroxidation (P ≤ 0.05). The group 5 (PSO + vitE) had numerically the lowest sperm with fragmented DNA (DNA Fr⁺) at 0 of the experiment and sperm with non-fragmented DNA (DNA Fr⁻) was lowest in group 6 (SFO + vitE) on da 40 the experiment. Testosterone level was not affected by the experimental diets (P > 0.05), however other hormones (LH and FSH) were affected. Based on the results, the supplementation of aged roosters’ diet with pumpkin seed oil + vitE improves reproductive performance which can be an appropriate strategy to preserve the reproductive performance of aged roosters.

Effects of increasing intake of soybean oil on synthesis of testosterone in Leydig cells

Background

Soybean oil is a very common edible oil in daily life. With the changes in the dietary composition, the intake of soybean oil increased. However, the effects of dietary intake of soybean oil on testosterone production are still unclear.

Methods

In order to study the effects of increasing intake of soybean oil on the synthesis of testosterone in Leydig cells, we fed male C57BL/6 mice on the diet which added 20% soybean salad oil (SOY group). We detected the hormone levels by enzyme-linked immunosorbent assay (ELISA) kits and serum fatty acid composition by gas chromatography, and analyzed the expression of steroidogenic enzymes by Real-Time PCR or immunoblotting analysis.

Results

After the 16-week feeding period, serum linoleic acid (LA) and α-linolenic acid (ALA) significantly increased and serum palmitic acid (PA) significantly decreased in SOY group mice. Compared to the normal diet (ND group), increasing intake of soybean oil raised the luteinizing hormone (LH) levels and up-regulated luteinizing hormone/chorionic gonadotropin receptor (LHCGR), steroidogenic acute regulatory protein (StAR) and cytochrome P450 family 11 subfamily A member I (CYP11A1). Testosterone levels in SOY group were higher than that in the ND group, and significantly difference showed.

Conclusions

Increasing intake of soybean oil could raise the serum LA and ALA levels and decrease serum PA levels. This could activate the LH/LHCGR pathway and improve the function of steroid synthesis in Leydig cells, and finally lead to the elevated testosterone levels.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-021-00580-1.

Reproductive characteristics, semen quality, seminal oxidative status, steroid hormones, sperm production efficiency of rabbits fed herbal supplements

Today, orthodox medicine has almost exceeded its limits in resolving subfertility problems in animals, thus making phytomedicine a primary tool in the treatment of infertility. In this work, three herbal supplements obtained from freshly air-dried Moringa oleifera, Phyllanthus amarus and Viscum album leaves were evaluated to ascertain their comparative effect on the reproductive potentials of bucks. Sixty bucks were allotted four diets made up of standard grower rabbit ration without supplement and with 5% Moringa, Mistletoe and Phyllanthus supplementation for 84 days. Semen samples were collected from all bucks using artificial vagina, for semen quality and seminal oxidative stress markers. The organ weights, testicular and epididymal spermatozoa reserves were assessed to determine sperm production potentials using standard procedures. The result obtained revealed that spermatozoa concentration, progressive motility, curvilinear velocity, average path velocity and the amplitude of lateral head was significantly (p < 0.05) higher in the group fed with mistletoe supplemented diet compared to that recorded in the control groups. The inclusion of herbal supplements linearly (p < 0.05) increased the seminal total antioxidant activity with a corresponding decrease in the seminal lipid peroxidation across the herbal supplemented treatments compared to the control. The gonadal and extra-gonadal sperm reserves of bucks fed on the herbal supplements were depleted compared to bucks on control. Bucks on mistletoe supplementation rivalled the superior daily sperm production and testicular sperm reserve in bucks without herbal supplements. In conclusion, Viscum album supplements in bucks' diets encouraged daily sperm production, testicular sperm reserves, testosterone, as well as spermatozoa kinetics. The three herbal supplements did enhance semen oxidative stability.

Peroxisome proliferator-activated receptors (PPARs) as a mediator of dietary fatty acids affects reproductive performance in broiler breeder roosters

This study analyzed the effects of dietary sources of omega-3 and omega-6 fatty acids on semen parameters and fertility potential in broiler breeder roosters. The mRNA and protein profiles of peroxisome proliferator-activated receptors-γ (PPAR-γ) expression in sperm as potential mediator of FAs were considered. Roosters were categorized into three groups and received their diets for 24 weeks as follows: 1) control diet received a basal diet (CTRL); 2) Fish oil based diet (FO) received the basal diet supplemented with 15 g/kg of diet fish oil; and 3) sunflower oil based diet (SO) received the basal diet supplemented with 15 g/kg of diet sunflower oil. While the different diets had significant effects on semen parameters, the effect of sampling time was not significant. The effect of the diets on sperm parameters were significantly higher in the SO and FO groups in total motility, progressive motility, amplitude of lateral head displacement, linearity, straightness, wobble and viability (P ≤ 0.05). Fertility rate was significantly improved in the FO and SO groups (P = 0001). The highest value for PPAR-γ mRNA was observed in the SO group compared to other groups (P ≤ 0.05). Moreover, supplementation of the roosters' diets with FO and SO increased PPAR-γ protein expression compared to the control. It seems that PPAR-γ could be a strong potential mediator of the underlying mechanism of improvement in semen parameters and reproductive performance of roosters under the effects of both dietary omega-3 and omega-6 polyunsaturated fatty acids.

Nutritional modulation of fertility in male poultry

The increased consumption of protein derived from poultry demands greater poultry production, but increased poultry production (meat and eggs) is dependent on the fertility of the parent flocks. Clearly, the fertility of poultry flocks is associated with the fertility of both males and females, but the low numbers of males used for natural or artificial insemination mean that their role is more important. Thus, enhancing the semen volume, sperm concentration, viability, forward motility, and polyunsaturated fatty acids in sperm, as well as protecting against oxidative damage, could help to optimize the sperm membrane functionality, mitochondrial activity, and sperm-egg penetration, and thus fertility. Therefore, this review summarizes the nutritional factors that could improve the fertility of poultry males as well as their associated mechanisms to allow poultry producers to overcome low-fertility problems, especially in aging poultry males, thereby obtaining beneficial impacts on the poultry production industry.

An integrated analysis of testis miRNA and mRNA transcriptome reveals important functional miRNA-targets in reproduction traits of roosters

The reproductive efficiency of roosters is an important trait in poultry production; however, the molecular mechanisms underlying this trait are not clearly understood. Here, we compared the mRNA and microRNA (miRNA) transcriptomes of testis from roosters with divergent sperm motility. A total of 302 differentially expressed genes (DEGs), including 182 upregulated genes and 120 downregulated genes, were identified in high sperm motility groups compared with low sperm motility groups. A subset of these DEGs related to steroid hormone biosynthesis and thus could be important for spermatogenesis. Additionally, we detected 13 differentially expressed miRNAs (DEMs) between two groups, and target gene prediction indicated seven of these could be associated with spermatogenesis. Based on a comprehensive analysis of these transcriptomes, miRNA-mRNA interaction networks were constructed. Six DEGs were predicted to be regulated by DEMs. Subsequently, we validated the negative regulation of family with sequence similarity 84, member A (FAM84A) by miR-215 using a dual-luciferase reporter system. These results provide new insights into the molecular profile of the testis and identify genes that may determine sperm motility in chickens.

Comparative transcriptome analysis digs out genes related to antifreeze between fresh and frozen-thawed rooster sperm

The objective of this study was to investigate differences in mRNA expression between fresh and frozen–thawed sperm in roosters. In trial 1, gene expression profiles were measured using microarray with Affymetrix GeneChip Chicken Genome Arrays. The results showed that 2,115 genes were differentially expressed between the 2 groups. Among these genes, 2,086 were significantly downregulated and 29 were significantly upregulated in the frozen–thawed sperm group. Gene Ontology (GO) analysis showed that more than 1,000 differentially expressed genes (DEG) of all significantly regulated genes were involved in GO terms including biological processes, molecular function, and cellular component. Kyoto Encyclopedia of Genes and Genomes analysis showed that DEG were significantly (P < 0.05) enriched on ribosome, oxidative phosphorylation, proteasome, cell cycle, oocyte meiosis, and spliceosome pathways. In trial 2, ejaculated semen was collected from 18 roosters and divided into 5 recombinant HSP90 protein–supplemented groups (0.01, 0.1, 0.5, 1, or 2 μg/mL) and one control group with no recombinant HSP90 protein supplementation to evaluate the effect of recombinant HSP90 protein in the extender on post-thaw quality of rooster semen. The results showed that post-thaw sperm viability and motility was significantly improved (P < 0.05) in the extender containing 0.5 and 1 μg/mL of recombinant HSP90 protein compared with the control. Our preliminary results will provide a valuable basis for understanding the potential molecular mechanisms of cryodamage in frozen–thawed sperm and theoretical guidance to improve the fertility of frozen–thawed chicken sperm.

Effect of dietary supplementation of whole flaxseed on sperm traits and sperm fatty acid profile in aged broiler breeder roosters

The objective of this study was to evaluate the effect of dietary supplementation of whole flaxseed on sperm traits and sperm fatty acid profile in aged broiler breeder roosters. Twelve Ross 308 broiler breeder roosters (age: 52 weeks; weight: 4,900 ± 210 g) haphazardly allotted to three dietary treatments (each treatment contained four replicates and one bird in each replicate) for six weeks. Treatments were different levels of flaxseed (0% flaxseed [GFL0], 2% flaxseed [GFL2] and 4% flaxseed [GFL4]). The feed intake quadratically decreased (p < .05) with increasing whole flaxseed levels for the period (58 to 60 weeks). Sperm traits (semen volume and sperm concentration, sperm total and forward motility, sperm viability and morphology, sperm plasma membrane functionality) were evaluated every two weeks (four times), and sperm fatty acid profile was assessed at the end of the experiment. Semen volume, sperm concentration and sperm morphology were not affected by treatments. On week 60, GFL2 group showed a significantly lower percentage of total and progressive sperm motility and sperm membrane functionality in comparison with the control and GFL4 groups. Also, sperm viability was lower in GFL2 group compared with other groups on week 58 (p < .05). In terms of sperm fatty acid profile, GFL2 group significantly reduced the percentage of linoleic acid (C18:2 [n-6]) in comparison with other groups. However, any of the other fatty acids were not affected by dietary flaxseed. In conclusion, dietary supplementation of whole flaxseed could not improve the quality of aged broiler breeder roosters' sperm in this study, nor it could alter the sperm fatty acid profile; thus, it seems necessary to use some antioxidants such as vitamin E in the diet of aged broiler breeder roosters, when supplementing the diets with oils or oilseeds such as flaxseed.

Effect of Dietary n-3 Source on Rabbit Male Reproduction

In the last two decades, the human sperm count linearly decreased in Western countries. Health problems, lifestyle, pollutants, and dietary behaviours are considered as the main risk factors, and the unbalance of dietary n‐6/n‐3 fatty acids is one of the most relevant. The aim of the present research is to study the effect of different dietary sources of n‐3 polyunsaturated fatty acids (PUFA) on reproductive traits using rabbit buck as the animal model. Fifteen rabbit bucks were assigned to three experimental groups: the control group, the FLAX group fed 10% extruded flaxseed, and the FISH group fed 3.5% fish oil for 110 days (50-day adaptation and 60-day experimental periods). Semen samples were collected weekly, whereas blood was collected every two weeks for the analytical determination of semen traits, oxidative status, fatty acid profiles, isoprostanes, neuroprostanes, and the immunocytochemistry of docosahexaenoic acid (DHA) and eicosapentaenoic (EPA) acid. At the end of the trial, the rabbits were killed and the testes were removed and stored for the analysis of fatty acid profile and immunocytochemistry. Results showed that dietary administration of n‐3 PUFA improved the track speed of the sperm and increased the n‐3 long-chain PUFA mainly confined in the sperm tail. Seminal plasma increased the thiobarbituric reactive substances (TBARs) by three times in the groups fed supplemental n‐3, whereas the F₂-isoprotanes (F₂-IsoPs) and F₄-neuroprostanes (F₄-NeuroPs) were lower and higher, respectively, in both supplemented groups than in the control. The testes and sperm showed a higher DHA and EPA distribution in rabbits from the n‐3 supplemented groups compared with the control. In conclusion, supplemental dietary n‐3 PUFA improved sperm motion traits and resulted in an enrichment of membrane fatty acid in the sperm and testes of the rabbits. However, such an increased amount of PUFA negatively affected the sperm oxidative status, which was mainly correlated with the generation of F₄-NeuroPs with respect to F₂-IsoPs. Accordingly, the latter cannot be considered a good marker of oxidation when diets rich in n‐3 PUFA are provided.