Conversion of α‐linolenic acid to long‐chain omega‐3 fatty acid derivatives and alterations of HDL density subfractions and plasma lipids with dietary polyunsaturated fatty acids in Monk parrots (Myiopsitta monachus)

Abstract

The effect of α-linolenic acid from a flaxseed (FLX)-enriched diet on plasma lipid and fatty acid metabolism and possible atherosclerosis risk factors was studied in Monk parrots (Myiopsitta monachus). Twenty-four Monk parrots were randomly assigned to diets containing either 10% ground SUNs or 10% ground FLXs. Feed intake was calculated daily. Blood samples, body condition scores and body weights were obtained at -5 weeks, day 0, 7, 14, 28, 42 and 70. Plasma samples were analysed for total cholesterol, free cholesterol, triacylglycerols and lipoproteins. Phospholipid subfraction fatty acid profiles were determined. By day 70, the FLX group had significantly higher plasma phospholipid fatty acids including 18:3n-3 (α-linolenic acid), 20:5n-3 (eicosapentaenoic acid) and 22:6n-3 (docosahexaenoic acid). The sunflower group had significantly higher plasma phospholipid levels of 20:4n-6 (arachidonic acid). By day 70, the high-density lipoprotein (HDL) peak shifted resulting in significantly different HDL peak densities between the two experimental groups (1.097 g/ml FLX group and 1.095 g/ml SUN group, p = 0.028). The plasma fatty acid results indicate that Monk parrots can readily convert α-linolenic acid to the long-chain omega-3 derivatives including docosahexaenoic acid and reduce 20:4n-6 accumulation in plasma phospholipids. The reason for a shift in the HDL peak density is unknown at this time.

Altered lipoprotein profiles in cats with hepatic lipidosis

“…Later, this technique was used to analyze lipoprotein profiles in dogs, 10 as well as other species. 32,33 In the present study, electron microscopic examination showed that feline lipoproteins were spherical and the diameters of the majority of lipoproteins that fell into the LDL density range were larger than those that fell into the HDL density range as has also been reported in humans and dogs. 34,35 In addition, feline lipoproteins in this study were smaller in diameter than what has previously been reported for lipoproteins in humans and dogs.…”

Lipoprotein characterization in Quaker parrots (Myiopsitta monachus) using gel‐permeation high‐performance liquid chromatography

“…Portomicrons first target the liver, unlike chylomicrons, which first target extra‐hepatic tissues 6 . Lipoprotein subtypes have also been identified in birds, but are poorly characterized in terms of relative abundance, composition, and clinical value 7,8 . Avian apolipoproteins also differ from mammals, and birds lack apoE and apoB‐48.…”

“…This technique is extremely time‐consuming, requiring 6‐30 hours of very high‐speed centrifugation with specialized equipment 16 . It is not offered commercially for animals, but has been used for research in pigeons, chickens, quails, geese, Quaker parrots, and cockatiels 6‐9,17‐20 . While this method allows separation and isolation of lipoprotein classes and subclasses, it does not allow the determination of lipoprotein particle numbers and sizes.…”

“…To analyze the content of lipid lipoprotein classes, a relatively large blood volume is also needed, and each fraction must be carefully collected from the centrifugal tubes prior to analysis; therefore, ultracentrifugation of small volumes to obtain a lipoprotein panel, typically by analytical ultracentrifugation, can only allow the determination of the relative distributions (% of total lipids). Absolute values are then determined from the total blood cholesterol levels and are not directly measured from each lipoprotein fraction 7‐9 . High centrifugal forces can also alter lipoprotein structure and composition 21 .…”

“…The Quaker parrot ( Myiopsitta monachus ) is a small parrot species that is highly susceptible to dyslipidemia and lipid accumulation disorders 10,14 . Thus, this parrot species is used in research to explore lipid metabolism and diseases of psittacine birds 7,8,12 . The objectives of this descriptive study were to characterize plasma lipoproteins of Quaker parrots using GP‐HPLC and to provide preliminary information on a wide range of plasma lipoprotein parameters in this species.…”