Association between dietary polyunsaturated fatty acids and their concentration in blood plasma, red blood cell, and semen of dogs.

Background: In dogs, dietary omega 3 polyunsaturated fatty acids (n-3 PUFA) affect the fatty acid (FA) profile of blood plasma, erythrocyte membrane (EM), and semen, but their correlation has not yet been investigated. Aim: In this study, we evaluated the association between dietary PUFA and their profile in blood plasma, EM, and semen of dogs, with the possibility to predict the semen profile using the values of the three first. Methods: Twelve male dogs received the same standard commercial diet for 4 weeks. The FA profile was analyzed by gas chromatography in paired diet, blood (plasma and EM determinations), and semen samples. Data were analyzed with SAS Proc Corr version 9.4. Pearson´s correlation coefficient (significant if p < 0.05) was used to assess the association of dietary FA profiles with those in blood plasma, EM, and semen. Results: There was a positive correlation between dietary eicosapentaenoic acid (EPA) and blood plasma (r = 0.97), EM (r = 0.94) and semen (r = 0.92) EPA, and between dietary docosahexaenoic acid (DHA) and arachidonic acid (ARA) and semen DHA (r = 0.93) and ARA (r = 0.92), respectively. There was a negative correlation between dihomo-gamma-linolenic acid (DGLA) in the diet and EM DGLA (r = -0.94). Conclusion: The dietary EPA is correlated with blood plasma, EM, and semen EPA concentrations, and dietary DHA and ARA are associated with semen DHA and ARA concentrations in dogs. These findings suggest that dietary EPA, DHA, and ARA concentrations could be helpful to predictive markers for such concentrations in the semen of dogs.

Effect of fish oil and vitamin E on sperm lipid peroxidation in dogs.

The objective was to evaluate the effects of dietary fish oil (FO) and vitamin E (VE) supplementation on sperm sensitivity to lipid peroxidation (LP) in dogs. Using an incomplete replicate 3 × 3 Latin square design, five dogs were allocated into three groups. One of the squares was incomplete and had two dogs that were used with three treatments. The dogs were assigned to three different treatments, fed a control diet of balanced commercial food (control group; CG), control diet supplemented with 54 mg FO/kg body weight0·75 per d (FO group; FG) and FO plus 400 mg VE per d (FO and VE group; FEG) for 60 d. Semen samples were collected on days 0 and 60 and divided into two halves, peroxidised and control, with or without ascorbate-Fe2+, respectively. LP was measured in both halves by chemiluminescence as counts per min/mg protein. Fatty acid profile was determined by GC. Data were analysed using the mixed procedure (SAS). On day 0, LP increased in all groups in the peroxidised samples (P < 0·05). However, on day 60 LP decreased in peroxidised samples of both the FG and FEG (P < 0·05), but there were no differences between the FG and FEG (P > 0·1). Additionally, on day 60 total n-3 was higher in the FG and FEG compared with the CG (P < 0·05). Supplementation with FO alone or together with VE decreased LP in peroxidised samples. These results could indicate a protective effect of n-3 on sperm. More studies are needed to understand the mechanism whereby FO and/or FO plus VE decrease LP in dogs' sperm.