The present study investigated the effect of dietary Zn deficiency during sexual maturation on sperm integrity and testis phospholipid fatty acid composition. Male weanling Sprague -Dawley rats were randomised into four dietary groups for 3 weeks: Zn control (ZC; 30 mg Zn/kg); Zn marginally deficient (ZMD; 9 mg Zn/kg); Zn deficient (ZD; ,1 mg Zn/kg); pair fed (PF; 30 mg Zn/kg) to the ZD group. Morphology of cauda epididymal sperm and lipid profiles of testis phospholipids were analysed. The rats fed the ZD diet had a lower testis weight (P, 0·02). Seminal vesicles and prostate weight were also lower in the ZD and PF groups. Rats fed the ZD diet, but not the ZMD diet, had 34 -35 % more abnormal spermatozoa and 24 % shorter sperm tail length than the ZC and PF rats (P, 0·001). Testis cholesterol concentration was higher in the ZD rats compared with the ZC and PF rats (P,0·04). Testes were highly enriched with n-6 fatty acids by showing n-6 : n-3 fatty acid ratios of 27:1 in phosphatidylcholine (PC) and 23:1 in phosphatidylethanolamine (PE). The dominant fatty acid in testes was docosapentaenoic acid (22 : 5n-6), comprising 15 and 24 % of PC and PE, respectively. This fatty acid was significantly lower in the ZD rats, whereas 18 : 2n-6 was higher compared with the rats in the other diet groups. These results demonstrate that severe Zn deficiency adversely affects sperm integrity and modulates testis fatty acid composition by interrupting essential fatty acid metabolism. This suggests that Zn deficiency-associated abnormal testicular function is perhaps preceded by altered membrane fatty acid composition, especially of a major fatty acid, 22 : 5n-6.
Highly enriched DHA and n-3 VLCFA in the retina lead to supernormal scotopic and photopic ERGs and increases in Müller cell reactivity and oxidative stress in photoreceptors. The regulation of n-3 fatty acids levels and of the n-6/n-3 fatty acid ratio are essential in preserving retinal integrity.
The present study investigated whether fatty acid compositions of testes are affected by the obese condition and dietary n-3 long-chain fatty acid (LCFA) intake. Male lean and obese Zucker rats were fed a 15 % (w/w, total diet) fat diet containing either 0 or 5·0 % (w/w, total fatty acids) n-3 LCFA for 8 weeks. Reproductive organ weights, sperm morphology and fatty acid composition of phosphatidylcholine (PC), and phosphatidylethanolamine (PE) of testes were analysed. The obese rats had significantly (P, 0·0001) smaller epididymides and seminal vesicles, larger prostates and abundant underdeveloped testes compared with lean rats. Diet treatment did not affect the sex organ weights. The effect of genotype on fatty acid composition was minor in PC and PE except for DHA (22 : 6n-3). The n-3 LCFA diet significantly (P, 0·0001) elevated 22 : 6n-3 and reduced arachidonic acid (20 : 4n-6) and DPA (22 : 5n-6) in testicular PC and PE of lean and obese rats compared with the control diet. The acylation of dietary n-3 LCFA into 22 : 6n-3 was 2-fold higher in obese rat testes than in lean rats fed the same diet. Underdeveloped testes had 70 % less 22 : 5n-6 in PC and PE than normal-size testes. Results indicate that testicular fatty acid composition is sensitive to dietary fat modulations and especially obese rats responded more to dietary n-3 LCFA than their lean counterparts. The selective reduction in 22 : 5n-6 in underdeveloped testes indicates that 22 : 5n-6 is important in male reproduction in rats and requires further study to define the role of elongation and desaturation in testicular development.
Lower body fat percentage is positively associated with climbing performance. This may lead climbers to practice unhealthy diet restriction when no sport-specific nutrition information exists. This study examined whether prolonged diet restriction affects body composition, oxidative stress, or other potential health risks in outdoor rock climbers. Two healthy male climbers conducted a 5 week rock climbing trip with a limited food budget ($1 each per day). Subjects underwent an energy restriction of approximately 40%. Loss of body weight and fat mass at week 5 were 5.8% and 16.1%, respectively, and were accompanied by significant subcutaneous fat loss in the iliac crest and abdomen. Triacylglycerols (TG), free fatty acids and C-reactive protein (CRP) dramatically decreased from baseline to week 2, and then maintained the lower level until week 5. Plasma vitamin C was below the normal range, and F2-isoprostanes, a marker of oxidative stress, continuously increased to week 5. Superoxide dismutase and glutathione peroxidase increased to week 2, but had returned to baseline levels at week 5. These results indicate that prolonged reduced energy intake while climbing may have an impact on weight loss and fat mass loss, which may contribute to low circulating TG and CRP, indicating improvements in markers of cardiovascular risk, and may lead to increased oxidative stress and reduced circulating antioxidants. Further studies are warranted to determine whether antioxidant supplementation or increased energy intake reduce oxidative stress.
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