Dietary polyunsaturated fatty acid supplementation of young post-pubertal dairy bulls alters the fatty acid composition of seminal plasma and spermatozoa but has no effect on semen volume or sperm quality.

The aim of this study was to examine the effects of dietary supplementation with rumen protected n-6 or n-3 polyunsaturated fatty acids (PUFA) on the quantity and quality of semen from young post-pubertal dairy bulls. Pubertal Holstein-Friesian (n = 43) and Jersey (n = 7) bulls with a mean ± s.e.m. age and bodyweight of 420.1 ± 5.86 days and 382 ± 8.94 kg, respectively, were blocked on breed, weight, age and semen quality (based on the outcomes of two pre-trial ejaculates) and randomly assigned to one of three treatments: (i) a non-supplemented control (CTL, n = 15), (ii) rumen-protected safflower (SO, n = 15), (iii) rumen-protected n-3 PUFA-enriched fish oil (FO, n = 20). Bulls were fed their respective diets, ad libitum for 12 weeks; individual intakes were recorded using an electronic feeding system for the initial 6 weeks of the feeding period. Semen was collected via electro-ejaculation at weeks -2, -1, 0, 7, 10, 11 and 12 relative to the beginning of the trial period (week 0). On collection, semen volume, sperm concentration and progressive linear motility (PLM) were assessed. On weeks -2, -1, 0, 10, 11, 12, semen was packaged into 0.25 mL straws and frozen using a programmable freezer. On weeks -1, 7 and 11; a sub-sample of semen was separated into sperm and seminal plasma, by centrifugation and stored at - 20 °C until analysis of lipid composition. Semen from 10 bulls per treatment were used for post-thaw analysis at weeks 10, 11 and 12 (3 straws per ejaculate). Sperm motility was analysed by computer assisted semen analysis (CASA). In addition, membrane fluidity, acrosome reaction and oxidative stress were assessed using flow cytometry. Sperm from bulls fed SO had a 1.2 fold higher total n-6 PUFA content at week 11 compared to week -1 (P < 0.01) while bulls fed FO had a 1.3 fold higher total n-3 PUFA content, in sperm by week 11 (P < 0.01). There was no effect of diet on semen volume, concentration or PLM of sperm when assessed either immediately following collection or post-thawing. Membrane fluidity and oxidative stress of sperm were also not affected by diet. The percentage of sperm with intact-acrosomes was lower in CTL bulls compared to those fed SO (P < 0.01). In conclusion, while the lipid composition of semen was altered following dietary supplementation with either n-6 or n-3 based PUFA, this did not lead to measurable improvements in the quantity or quality of semen produced by young post-pubertal dairy bulls.

Byrne CJ ，Fair S ，English AM ，Holden SA ，Dick JR ，Lonergan P ，Kenny DA ... -  《-》

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

The objective of this study was to examine the effect of dietary n-3 polyunsaturated fatty acid (PUFA) supplementation of rams on semen quality and subsequent sperm function of liquid stored semen. Mature rams of proven fertility were individually housed and were blocked according to breed, body weight, and body condition score and randomly allocated within block to one of two dietary treatments (N = 7 per treatment). Rams were offered a base diet of hay and concentrate, with the concentrate enriched with either: (1) saturated palmitic acid (CON) or (2) high n-3 PUFA fish oil (FO) supplements. Both lipid supplements were added at 2% (wt/wt) of the total diet as fed and both were partially rumen-protected. The animals were fed their respective diets for a total of 9 weeks and blood samples were collected on weeks 0 (pre-experimental), 4, and 9, relative to initial allocation of diet (week 0), for measurement of plasma concentration of fatty acids, metabolites, insulin like growth factor 1 (IGF-1) and insulin. Semen was collected from each ram (on 1 day in each week) in weeks 4, 5, 7, 8, and 9, and each ejaculate was assessed for volume, wave motion, and concentration of sperm, after which it was diluted in a skim milk-based extender and stored at 4 °C. A second ejaculate was collected on weeks 4, 7, and 9, centrifuged, and the sperm frozen for subsequent lipid analysis. A sample of semen from each ram was assessed at 24, 48, and 72 hours after collection for sperm progressive linear motion, ability to penetrate artificial mucus, and the ability to resist lipid peroxidation (at 24 and 48 hours only) using the thiobarbituric acid reactive substances assay. There was no effect of diet on plasma insulin concentrations or on any of the metabolites measured, however, there was a diet by week interaction for plasma IGF-1 concentration (P < 0.05). This was manifested as the FO supplemented rams having higher IGF-1 concentrations on week 9 compared with the control treatment (P < 0.05), but not at the earlier sampling dates. Compared with the pre-experimental values, supplementation with FO increased plasma concentrations of total n-3 PUFAs by 3.1-fold and decreased n-6 PUFA concentrations by 1.84-fold. Consequently, the ratio of n-6 to n-3 PUFA was decreased in the FO-supplemented rams (P < 0.001). Dietary supplementation with FO increased the concentration of eicosapentaenoic acid in sperm from week 4 to 9 by 2.7-fold (P < 0.05) leading to a 1.5-fold increase in total n-3 PUFA in the same period. Ejaculates collected from rams supplemented with FO yielded a higher semen concentration (P < 0.05), however, there was no difference between diets on any of the other semen quality parameters including semen volume, wave motion, progressive linear motion, ability to penetrate artificial mucus, or ability to resist lipid peroxidation. In conclusion, dietary supplementation of rams with n-3 PUFA successfully increased the n-3 PUFA content of plasma and sperm but has limited effects on the quality of liquid stored semen.

Fair S ，Doyle DN ，Diskin MG ，Hennessy AA ，Kenny DA ... -  《-》

Dietary n-3 PUFAs improve fresh and post-thaw semen quality in Holstein bulls via alteration of sperm fatty acid composition.

The goal of this study was to investigate the effect of fish oil-supplemented diet on fresh and post-thaw semen quality and sperm lipid composition in bulls. Bulls were randomly assigned to two groups (n = 6). Six bulls were used as the control group and six received the fish oil (1.2% dry matter of total diet) for 11 weeks. Semen was individually collected from each bull and frozen biweekly. Semen volume, sperm concentration, viability, progressive motility, and fatty acid profile of sperm were measured in 1st, 3rd, 5th, 7th, 9th, and 11th week of experiment. Viability, progressive motility, and fatty acid profile of post-thaw sperm were also measured in 3rd, 5th, 9th, and 11th week of experiment. Data were analyzed with using Proc GLM or MIXED (for repeated measurement data) in SAS program. The fish oil-supplemented diet increased the semen volume and sperm concentration. The fish oil-supplemented diet also altered the viability, progressive motility, and fatty acid profile of fresh and post-thaw sperm. In conclusion, feeding a fish oil-enriched diet via alteration of fatty acid profile of sperm lipid could improve in vitro quality of fresh and post-thaw sperm in Holstein bulls.

Khoshvaght A ，Towhidi A ，Zare-Shahneh A ，Noruozi M ，Zhandi M ，Dadashpour Davachi N ，Karimi R ... -  《-》

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.

Karimi R ，Towhidi A ，Zeinoaldini S ，Rezayazdi K ，Mousavi M ，Safari H ，Martinez-Pastor F ... -  《-》

Dietary inclusion of fish oil changes the semen lipid composition but does not improve the post-thaw semen quality of ram spermatozoa.

The aim of this study was to investigate the effects of dietary fish oil (FO) time-response on the fatty acid profile, cholesterol levels and sperm cryosurvival in ram semen. Criollo Araucano rams were randomly assigned to two groups (n=4) according to the type of supplementation: a control group without FO and a supplemented group fed a diet with 3% FO for 8 weeks. The semen lipid profile and post-thaw sperm quality were analyzed at weeks 0 (pre-supplementation), 4, 8, 12 and 16 (post-supplementation) to evaluate the effects of FO supplementation by time interaction. Post-thaw sperm quality was determined by CASA and flow cytometry. In spermatozoa, the supplemented group increased the linoleic acid (C18:2n6c) and docosahexaenoic acid (DHA; C22:6n3) with levels higher at week 16 (P<0.05). The effect of FO on cholesterol concentration in sperm was significant at the end of the experiment (week 16). In seminal plasma, statistical differences of butyric acid (C4:0), palmitic acid (C16:0), stearic acid (C18:0), eicosatrienoic acid (C20:3n3) and DHA were observed at week 12. The cholesterol concentration was not affected by dietary treatments (P>0.05). However, the post-thaw sperm quality of the FO treatment group decreased. Motility percentage decreased 50% and spermatozoa with permeable plasma membrane and reacted acrosome were higher (63%) at week 16 than the control group. These results showed that DHA was effectively incorporated into semen through dietary supplementation with FO, but evaluations of post-thaw sperm quality confirm alteration specificity related to the structure of the lipid bilayer.

Díaz R ，Torres MA ，Paz E ，Quiñones J ，Bravo S ，Farías JG ，Sepúlveda N ... -  《-》