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Description:
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Long -chain polyunsaturated fatty acids (LCPUFA ) are essential for proper neural and retinal development in many mammalian species . One objective of this research was to investigate the effects of dietary & #945 ; -linolenic acid (ALA ) and LCPUFA on the fatty acid composition of canine plasma phospholipids (PL ) and milk during the gestation and lactation periods . The fatty acid composition of plasma PL and the retinal development of puppies reared on the same experimental diets as their mothers were also investigated .
Enriching the canine gestation /lactation diet with ALA (6 .8 % DM ) does not result in enrichment of docosahexaenoic acid (DHA ) in the milk . From this data it can be inferred that peroxisomal elongation and desaturation of LCPUFA does not occur in canine mammary tissue . Dose responses of linoleic acid (LA ) , ALA and DHA were observed in the plasma of adult dogs during gestation and lactation and in puppies during both the suckling and post -weaning periods . Plasma PL fatty acid data from puppies indicate that canine neonates are capable of synthesizing LCPUFA from ALA , but that plasma enrichment of the newly -synthesized DHA does not compare with that obtained from preformed DHA in the diet .
Visual function was assessed via electroretinography (ERG ) in 12 -wk old canines . One -way ANOVA revealed significantly better visual performance in dogs fed the highest amounts of n -3 LCPUFA . Puppies in this group demonstrated the greatest rod response as measured by the amplitude and implicit time of the a -wave . Neonates reared on the lowest dietary levels of both ALA and n -3 LCPUFA exhibited the poorest visual function . A novel parameter devised in this study was the threshold intensity , which was the initial intensity at which the a -wave was detectable . Again , puppies consuming the greatest concentrations of n -3 LCPUFA responded significantly sooner , i .e . exhibited greater rod sensitivity , than other diet groups .
The findings of this research underscore the importance of preformed n -3 LCPUFA in the diet , rather than ALA , as a means of enriching neural tissues in DHA during the developmental period . Moreover , dietary DHA appears to be related to improved visual performance in developing canines . |