Effect of dietary omega-3 fatty acids on red blood cell lipid composition and plasma metabolites in the cockatiel, Nymphicus hollandicus

Comparison of Lipoprotein Analysis Using Gel-Permeation High-Performance Liquid Chromatography and a Biochemistry Analyzer in Normolipidemic and Dyslipidemic Quaker Parrots (Myiopsitta monachus)

Lipid accumulation disorders are common in psittacine birds and can be associated with changes in plasma lipoproteins, most notably low-density lipoprotein (LDL) and high-density lipoprotein (HDL). However, lipoprotein analysis by standard laboratory analyzers or an indirect method, such as the Friedewald formula, has not been validated in parrots. A research colony of 12 Quaker parrots (Myiopsitta monachus) were used to compare plasma values from the Roche Cobas c501 biochemistry analyzer for total cholesterol, total triglycerides, LDL, and HDL to gel-permeation high-performance liquid chromatography (GP-HPLC). To increase sample size and broaden the analytical range to include dyslipidemic samples, 2 cross-over studies were performed on a 0.3% cholesterol diet and a 20% fat diet. Agreement between methods was assessed by linear mixed models and Bland and Altman plots. The LDL concentrations calculated by the Friedewald formula and alternative formulas, and the effects of triglycerides on the biases, were also evaluated. Forty-five plasma samples were used. The cholesterol diet induced a marked increase in cholesterol and all lipoproteins, whereas the fat diet did not lead to dyslipidemia. Direct and indirect LDL measurements obtained with the clinical analyzer were not in clinical agreement with GP-HPLC, whereas HDL had acceptable agreement for normotriglyceridemic samples. Hypertriglyceridemic plasma samples were found to interfere with lipoprotein measurements. This study found LDL measured by the Roche Cobas c501 biochemistry analyzer and indirect estimations cannot be recommended in the Quaker parrot, and non-HDL cholesterol should be used instead. Lipoprotein panels obtained from hypertriglyceridemic samples should be interpreted with care.

Treatment of Pain in Birds

This article provides an overview of the current understanding of evidence-based clinical analgesic use in birds. The field of avian analgesia has dramatically expanded during the last 20 years, affording more options for alleviating both acute and chronic pain. These options include opioids, nonsteroidal anti-inflammatory drugs, local anesthetics, and/or other drugs like gabapentin, amantadine, and cannabinoids, acting at different points in the nociceptive system thereby helping to provide greater pain relief while reducing the risk of adverse effects when combined.

Blood Lipid Diagnostics in Psittacine Birds

Lipids are the main biomolecular constituents of plasma and occupy a central place in the pathophysiology of several common diseases of parrots. Dyslipidemias frequently occur in psittacine birds in relation to a variety of lipid accumulation disorders and female reproductive disorders. The five main lipid classes in the plasma are sterols, fatty acyls, glycerolipids, glycerophospholipids, and sphingolipids. Most lipids are transported in the blood within lipoproteins. Lipidologic diagnostic tests to characterize dyslipidemias and risk factors of lipid disorders include routine biochemical tests such as cholesterol and triglycerides, lipoprotein testing, and newer comprehensive techniques to assess whole lipid pathways using lipidomics.

Effects of a 0.3% cholesterol diet and a 20% fat diet on plasma lipids and lipoproteins in Quaker parrots (Myiopsitta monachus)

BACKGROUND

Lipid disorders are common in captive psittacine birds, but associated changes in blood lipids and lipoproteins have not been well characterized. The Quaker parrot is prone to dyslipidemia and has been extensively used as an experimental model.

OBJECTIVES

We aimed to study the effects of a 0.3% cholesterol diet and a 20% fat diet on plasma lipids and lipoproteins in Quaker parrots.

METHODS

Two crossover studies were performed with each diet. During each study, 12 parrots were divided into two groups fed the treatment or control diet for 2 weeks. After a 2-month wash-out period, the groups were reversed. At the end of each period, plasma lipidomics and lipoprotein profiling were performed. Data were analyzed by univariate tests adjusted for false discovery rates, volcano plots, and enrichment analyses.

RESULTS

The cholesterol diet induced changes in many plasma lipids and lipoproteins. Total cholesterol and cholesteryl esters were significantly and markedly elevated. Ceramides were the second subclass of lipids that were elevated. Several glycerophosphocholines, sphingomyelins, and one diacylglycerol were also significantly elevated, albeit to a lesser magnitude. All lipoproteins were elevated, with the greatest increase seen in non-HDL. The fat diet mainly resulted in a decrease in plasma glycerolipids and an increase in acylcarnitines. Lipoprotein plasma levels remained unchanged.

CONCLUSIONS

Quaker parrots fed a 0.3% cholesterol diet showed profound and complex dyslipidemic changes that could be used to further study lipid disorders and their management in psittacine birds. A 20% fat diet higher in n-6 polyunsaturated fatty acids did not lead to dyslipidemia.

Baseline Insulin Resistance Is a Determinant of the Small, Dense Low-Density Lipoprotein Response to Diets Differing in Saturated Fat, Protein, and Carbohydrate Contents

Individual responses to diet vary but causes other than genetics are poorly understood. This study sought to determine whether baseline values of homeostasis model assessment (HOMA-IR) was related to changes in small, dense low-density lipoprotein (sdLDL, i.e., LDL4, d = 1.044-1.063 g/mL) amounts quantified by isopycnic density profiling, in mildly hypercholesterolemic subjects (n = 27) consuming one of three low saturated fatty acid (SFA) diets: Dietary Approaches to Stop Hypertension (DASH), Beef in an Optimal Lean Diet (BOLD) and BOLD plus extra protein (BOLD+) when compared to a higher-SFA healthy American diet (HAD). The diets were consumed in random order for 5 wk, with 1 wk between diets. BOLD+ reduced fractional abundance (%) LDL4 (p < 0.05) relative to HAD, DASH and BOLD, and reductions in % LDL4 correlated with reductions in triglycerides (p = 0.044), total cholesterol (p = 0.014), LDL cholesterol (p = 0.004) and apolipoprotein B (p < 0.001). Responses to the four diets were similar (~12% decrease in % LDL4, p = 0.890) in the lower (<2.73 median) HOMA-IR subgroup but differed across diet conditions in the higher HOMA-IR subgroup (p = 0.013), in which % LDL4 was reduced with BOLD+ (-11%), was unchanged in BOLD and increased with the HAD (8%) and DASH (6%) diets (p < 0.05 for BOLD+ vs. HAD). Individual responses to diet interventions are influenced by presence and degree of insulin resistance as measured by HOMA-IR.

Omega-3 fatty acids accelerate fledging in an avian marine predator: a potential role of cognition

Consuming omega-3 fatty acids (n-3 LCPUFAs) during development improves cognition in mammals, but the effect remains untested in other taxa. In aquatic ecosystems, n-3 LCPUFAs are produced by phytoplankton and bioaccumulate in the food web. Alarmingly, the warming and acidification of aquatic systems caused by climate change impair n-3 LCPUFA production, with an anticipated decrease of 80% by the year 2100. We tested whether n-3 LCPUFA consumption affects the physiology, morphology, behaviour and cognition of the chicks of a top marine predator, the ring-billed gull. Using a colony with little access to n-3 LCPUFAs, we supplemented siblings from 22 fenced nests with contrasting treatments from hatching until fledging; one sibling received n-3 LCPUFA-rich fish oil and the other, a control sucrose solution without n-3 LCPUFAs. Halfway through the nestling period, half the chicks receiving fish oil were switched to the sucrose solution to test whether n-3 LCPUFA intake remains crucial past the main growth phase (chronic versus transient treatments). Upon fledging, n-3 LCPUFAs were elevated in the blood and brains of chicks receiving the chronic treatment, but were comparable to control levels among those receiving the transient treatment. Across the entire sample, chicks with elevated n-3 LCPUFAs in their tissues fledged earlier despite their morphology and activity levels being unrelated to fledging age. Fledging required chicks to escape fences encircling their nest. We therefore interpret fledging age as a possible indicator of cognition, with chicks with improved cognition fledging earlier. These results provide insight into whether declining dietary n-3 LCPUFAs will compromise top predators' problem-solving skills, and thus their ability to survive in a rapidly changing world.

The plasma lipidome of the Quaker parrot (Myiopsitta monachus)

Dyslipidemias and lipid-accumulation disorders are common in captive parrots, in particular in Quaker parrots. Currently available diagnostic tests only measure a fraction of blood lipids and have overall problematic cross-species applicability. Comprehensively analyzing lipids in the plasma of parrots is the first step to better understand their lipid metabolism in health and disease, as well as to explore new lipid biomarkers. The plasma lipidome of 12 Quaker parrots was investigated using UHPLC-MS/MS with both targeted and untargeted methods. Targeted methods on 6 replicates measured 432 lipids comprised of sterol, cholesterol ester, bile acid, fatty acid, acylcarnitine, glycerolipid, glycerophospholipid, and sphingolipid panels. For untargeted lipidomics, precursor ion mass-to-charge ratios were matched to corresponding lipids using the LIPIDMAPS structure database and LipidBlast at the sum composition or acyl species level of information. Sterol lipids and glycerophospholipids constituted the majority of plasma lipids on a molar basis. The most common lipids detected with the targeted methods included free cholesterol, CE(18:2), CE(20:4) for sterol lipids; PC(36:2), PC(34:2), PC(34:1) for glycerophospholipids; TG(52:3), TG(54:4), TG(54:5), TG(52:2) for glycerolipids; SM(d18:1/16:0) for sphingolipids; and palmitic acid for fatty acyls. Over a thousand different lipid species were detected by untargeted lipidomics. Sex differences in the plasma lipidome were observed using heatmaps, principal component analysis, and discriminant analysis. This report presents the first comprehensive database of plasma lipid species in psittacine birds and paves the way for further research into blood lipid diagnostics and the impact of diet, diseases, and drugs on the parrot plasma lipidome.

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

BACKGROUND

Lipid accumulation disorders, such as atherosclerosis and hepatic lipidosis, are common in psittacine birds and associated with various dyslipidemias. Gel-permeation high-performance liquid chromatography (GP-HPLC) is a reference method for advanced lipoprotein profiling based on particle size separation, followed by an analysis of lipid contents.

OBJECTIVES

The objectives were to (a) characterize Quaker parrot lipoproteins using a commercial GP-HPLC method (Liposearch panel), and (b) obtain preliminary information on the reliability of the Friedewald formula for low-density lipoprotein-cholesterol (LDL-C) measurements.

METHODS

Plasma samples were collected from 12 fasted healthy Quaker parrots. Cholesterol concentrations, triglyceride concentrations, particle sizes, and particle numbers were determined by GP-HPLC for four classes and 20 sub-fractions of lipoproteins. The LDL-C concentrations obtained using the Friedewald formula and direct measurements were compared with Bland-Altman plots. Alternate formulas were determined using multiple linear regression.

RESULTS

High-density lipoprotein (HDL) was the predominant lipoprotein in Quaker parrots, and most particles were of medium-to-small sizes belonging to two sub-fractions (average size, 10.6 nm). LDL was the second most common lipoprotein and included large-to-small particles belonging to three sub-fractions (average size, 24.9 nm). Very-low-density lipoproteins (VLDL) and portomicrons were present in low concentrations. The Friedewald formula underestimated LDL-C concentrations with a significant bias of 0.44 mmol/L. An alternate formula was proposed: LDL-C = 0.75*Non-HDL-C.

CONCLUSIONS

GP-HPLC allowed unprecedented characterization of plasma lipoproteins in Quaker parrots. Characterizing psittacine lipoprotein is useful for validation and interpretation of routine clinical tests as well as for use in epidemiologic and experimental research on psittacine lipid accumulation disorders.

Clinical Management of Avian Renal Disease

Treatment of avian renal disease relies on supportive care, such as fluid therapy and nutritional support. Analgesia and adaptations of the environment are indicated in cases of renal disease associated with painful joints. Other treatments vary with the underlying etiology and may include systemic antibiotics, antifungal therapy, vitamin A supplementation, or chelation therapy.

Reproductive Characteristics of Cockatiels (Nymphicus hollandicus) Maintained in Captivityand Receiving Madagascar Cockroach (Gromphadorhina portentosa) Meal

The aim of this study was to evaluate the use of a Madagascar cockroach (Gromphadorhina portentosa) meal in the feed of cockatiels (Nymphicus hollandicus) in captivity and its influence on the reproductive characteristics of these birds. Twelve pairs of birds were used during two subsequent reproductive cycles of 130 days each, with time divided into four phases: laying, incubation, rearing of chicks until 30 days of age, and return to the new laying phase. The pairs were divided into two groups: a control group, which received a commercial diet for psittacines + a mixture of seeds, and a test group, which received the same diet as the control group except for the addition of a Madagascar cockroach meal in a ratio of 14 g of commercial food to 1 g of cockroach meal (6.6%). After hatching, chicks remained with their parents until 30 days of age. Subsequently, the chicks were transferred to another room and monitored until the 90th day of life. The inclusion of cockroach meal did not influence (p > 0.05) the intake of commercial food and mixture of seeds during the reproductive phases evaluated, except for feed intake, which was increased relative to control values (p = 0.02) in the return-to-laying phase. Yolk cholesterol content, egg width and egg shape index were increased with the inclusion of the cockroach meal, whereas the number of days to return to the new laying phase was reduced compared to the control (p = 0.02). The number of eggs laid decreased (p < 0.05) with the inclusion of the cockroach meal; however, the percentage of hatching was higher in the test group than in the control group (p < 0.05). No significant effect (p > 0.05) of dietary treatment was observed on the number of viable chicks at 1, 30 and 90 days of age or on the contents of most fatty acids present in the yolk. The findings of this study indicate that a Madagascar cockroach meal can be used as an alternative feedstuff in the diets for cockatiels and can lead to minor improvements in reproductive characteristics when replacing 6.6% of the commercial pelleted diet.

Cluster of atherosclerosis in a captive population of black kites (Milvus migrans subsp.) in France and effect of nutrition on the plasma lipid profile

From January 2010 to March 2013, a captive colony of 83 black kites (Milvus migrans subsp.) in France experienced increased mortality related to atherosclerosis with an incidence of 4.4% per year. On histopathology, all kites had advanced atherosclerotic lesions, with several birds presenting abdominal hemorrhage and aortic rupture. In January 2012, a dietary change was instituted and consisted of introducing fish into the kites' diet. During the following 15 mo, the plasma lipid profile was monitored as well as body weight, food offered, and flight activity. Total and low-density lipoprotein cholesterol initially increased, but in December 2012 and March 2013, an overall decrease from initial values was observed. High-density lipoprotein cholesterol also increased during this period. Despite positive plasma lipid changes induced by dietary modifications, there was no decrease in mortality from atherosclerosis, which was probably associated with the severity of the atherosclerotic lesions at time of dietary management. However, owing to the long and progressive development of atherosclerotic lesions, long-term beneficial effects are probable. This report suggests that black kites are particularly susceptible to atherosclerosis and aortic dissection in captivity. To prevent degenerative diseases associated with captivity in birds of prey, species-specific lifestyle and dietary requirements and susceptibility to these diseases should be considered.

Manipulation of culture conditions alters lipid content and fatty acid profiles of a wide variety of known and new oleaginous yeast species

Oleaginous yeasts have been studied for oleochemical production for over 80 years. Only a few species have been studied intensely. To expand the diversity of oleaginous yeasts available for lipid research, we surveyed a broad diversity of yeasts with indicators of oleaginicity including known oleaginous clades, and buoyancy. Sixty-nine strains representing 17 genera and 50 species were screened for lipid production. Yeasts belonged to Ascomycota families, Basidiomycota orders, and the yeast-like algal genus Prototheca. Total intracellular lipids and fatty acid composition were determined under different incubation times and nitrogen availability. Thirteen new oleaginous yeast species were discovered, representing multiple ascomycete and basidiomycete clades. Nitrogen starvation generally increased intracellular lipid content. The fatty acid profiles varied with the growth conditions regardless of taxonomic affiliation. The dominant fatty acids were oleic acid, palmitic acid, linoleic acid, and stearic acid. Yeasts and culture conditions that produced fatty acids appropriate for biodiesel were identified.