Dietary choline and phospholipid supplementation enhanced docosahexaenoic acid enrichment in egg yolk of laying hens fed a 2% Schizochytrium powder-added diet

Harnessing oleaginous protist Schizochytrium for docosahexaenoic acid: Current technologies in sustainable production and food applications

Docosahexaenoic acid (DHA) exerts versatile roles in nutrition supplementation and numerous health disorders prevention. Global consumption demand for DHA has also been consistently increasing with enhanced health awareness. Oleaginous marine protist Schizochytrium is praised as a potential DHA source due to short growth cycle, convenient artificial culture, harmless to the human body, and easy manipulation of the DHA synthesis pathway. However, factors including strain performances, fermentation parameters, product harvest and extraction strategies, safety and stability maintenance, and also application limitations in health and functional properties affect the widespread adoption of Schizochytrium DHA products. This review provides a comprehensive summary of the current biotechnologies used for tackling factors affecting the Schizochytrium DHA production, with special focuses on Schizochytrium strain improvement technologies, fermentation optimization projects, DHA oil extraction strategies, safety evaluations and stability maintenance schemes, and DHA product application approaches in foods. Inspired by systematic literature investigations and recent advances, suggestive observations composed of improving strain with multiple breeding technologies, considering artificial intelligence and machine learning to optimize the fermentative process, introducing nanoparticles packing technology to improve oxidation stability of DHA products, covering up DHA odor defect with characteristic flavor foods, and employing synthetic biology to construct the structured lipids with DHA to exploit potential functions are formed. This review will give a guideline for exploring more Schizochytrium DHA and propelling the application development in food and health.

Comprehensive Lipidomic Analysis of Three Edible Microalgae Species Based on RPLC-Q-TOF-MS/MS

Microalgae, integral to marine ecosystems for their rich nutrient content, notably lipids and proteins, were investigated by using reversed-phase liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (RPLC-Q-TOF-MS/MS). This study focused on lipid composition in three commonly used microalgae species (Spirulina platensis, Chlorella vulgaris, and Schizochytrium limacinum) for functional food applications. The analysis unveiled more than 700 lipid molecular species, including glycolipids (GLs), phospholipids (PLs), sphingolipids (SLs), glycerolipids, and betaine lipids (BLs). GLs (19.9-64.8%) and glycerolipids (24.1-70.4%) comprised the primary lipid. Some novel lipid content, such as acylated monogalactosyldiacylglycerols (acMGDG) and acylated digalactosyldiacylglycerols (acDGDG), ranged from 0.62 to 9.68%. The analysis revealed substantial GLs, PLs, and glycerolipid variations across microalgae species. Notably, S. platensis and C. vulgaris displayed a predominance of fatty acid (FA) 18:2 and FA 18:3 in GLs, while S. limacinum exhibited a prevalence of FA 16:0, collectively constituting over 60% of the FAs of GLs. In terms of PLs and glycerolipids, S. platensis and C. vulgaris displayed elevated levels of arachidonic acid (AA) and eicosapentaenoic acid (EPA), whereas S. limacinum exhibited a significant presence of docosahexaenoic acid (DHA). Principal component analysis (PCA) revealed MGDG (16:0/18:1), DG (16:0/22:5), Cer (d18:1/20:0), and LPC (16:1) as promising lipid markers for discriminating between these microalgae samples. This study contributes to a comprehensive understanding of lipid profiles in three microalgae species, emphasizing their distinct biochemical characteristics and potentially informing us of their high-value utilization in the food industry.

Effects of Hydroxylated Lecithin on Growth Performance, Serum Enzyme Activity, Hormone Levels Related to Lipid Metabolism and Meat Quality in Jiangnan White Goslings

The objective of the present study was to evaluate the effects of hydroxylated lecithin on growth performance, serum enzyme activity, hormone levels related to lipid metabolism and meat quality in Jiangnan White goslings. Six hundred 1-day-old goslings were randomly divided into five treatments with six replicates and 20 for each replicate. The control group (CG) was fed the basal diet, while the experimental group was fed the basal diet with 50, 100, 200 mg/kg hydroxylated lecithin and 100 mg/kg soy lecithin (HLG50, HLG100, HLG200, and LG100, respectively) in the form of powder. Feed and water were provided ad libitum for 32 days. Compared with the CG, (a) the average daily feed intake was higher (P < 0.05) in HLG100, the final body weight and average daily gain were higher (P < 0.05), and the feed conversion ratio was lower in the HLG200; (b) the alanine aminotransferase, malate dehydrogenase, leptin, glucagon, thyroid hormone, Triiodothyronine contents in the HLG200 were lower (P < 0.05); (c) The breast muscle water holding capacity was higher (P < 0.05) in groups with hydroxylated lecithin, the breast muscle shear force and fiber diameter were lower (P < 0.05) in the HLG100; (d) the inositic acid, intramuscular fat, phospholipid contents were higher (P < 0.05), the triglyceride content was lower (P < 0.05) in HLG100 of the breast muscle; (e) the relative expression of sterol regulatory element-binding protein-1 genes were higher (P < 0.05) in the treated groups of muscles, the phosphorylase kinase gamma subunit 1 gene expression was shown an opposite trend. In comparison with LG100, (a) the feed conversion ratio was lower (P < 0.05) in HLG200; (b) the alanine aminotransferase and adiponectin contents were higher (P < 0.05), the malondialdehyde and free fatty acid contents were lower (P < 0.05) in HLG200; (c) the water holding capacity and intramuscular fat contents in the breast and leg muscles were higher (P < 0.05) in HLG200. The hydroxylated lecithin concentration of 200 mg/kg improved the growth performance, serum enzyme activity, hormone levels related to lipid metabolism, and the meat quality of Jiangnan White goslings.

Dietary microalgae on poultry meat and eggs: explained versus unexplained effects

Different types and sources of microalgae are used to feed broiler chickens and laying hens. This review provides a concise update on various impacts of feeding these novel ingredients on physical, chemical, and nutritional attributes of the resultant meat and eggs. Some of the observed effects may be associated with biochemical and molecular mechanisms derived from unique chemical compositions and nutritional values of microalgae. However, the full potential and the accurate mechanism of microalgae in producing health-promoting poultry foods remain to be explored.

Astaxanthin improved the storage stability of docosahexaenoic acid-enriched eggs by inhibiting oxidation of non-esterified poly-unsaturated fatty acids

This study assessed the potential and mechanism of action of astaxanthin, to improve the stability of docosahexaenoic acid (22:6(n-3); DHA) enriched egg products, during storage at 4 °C. The reduction in DHA content after 42 days of storage in astaxanthin-DHA eggs (from hens fed supplemental astaxanthin and DHA) was <3%, whereas the reduction in regular-DHA eggs (hens fed DHA only) was over 17%. Astaxanthin also decreased production of oxidation products including 4-hydroxy-2-hexenal, 4-hydroxy-2-nonenal and malondialdehyde in eggs during storage, thus markedly improving the oxidative stability of DHA-enriched eggs. The yolk lipidomic profile showed higher intensities for most DHA-containing lipids, especially DHA-phosphatidylcholine, DHA-phosphatidylethanolamine and DHA-non-esterified fatty acid, compared with regular-DHA eggs. Astaxanthin acts primarily by suppressing oxidation of DHA-non-esterified fatty acid, which minimizes the degradation of DHA and appears to be the primary protection mode of yolk DHA during storage.

Effect of Oils in Feed on the Production Performance and Egg Quality of Laying Hens

With the development of a large-scale and intensive production industry, the number of laying hens in China is rapidly increasing. Oils, as an important source of essential fatty acids, can be added to the diet to effectively improve the production performance and absorption of other nutrients. The present review discusses the practical application of different types and qualities of oils in poultry diets and studies the critical effects of these oils on production performance, such as the egg weight, feed intake, feed conversion ratio (FCR), and various egg quality parameters, including the albumen height, Haugh units, yolk color, and saturated/unsaturated fatty acids. This article reviews the effects of different dietary oil sources on the production performance and egg quality of laying hens and their potential functional mechanisms and provides a reference for the selection of different sources of oils to include in the diet with the aim of improving egg production. This review thus provides a reference for the application of oils to the diets of laying hens. Future studies are needed to determine how poultry products can be produced with the appropriate proper oils in the diet and without negative effects on production performance and egg quality.

Performance and Egg Quality of Laying Hens Fed Diets Containing Raw, Hydrobarothermally-Treated and Fermented Rapeseed Cake

The present study was conducted to investigate how raw rapeseed cake (RRC), hydrobarothermally-treated rapeseed cake (HRC) and fermented rapeseed cake (FRC) fed to laying hens over a period of 12 weeks affected their performance, and the quality, fatty acid (FA) profile and oxidative stability of eggs. A total of 304 Hy-Line Brown laying hens at 36 weeks of age were distributed in a completely randomized design to four treatment groups with 38 replicates per treatment and two hens per replicate. The birds had ad libitum access to feed and water throughout the study. During the experiment, the birds were fed isonitrogenous and isocaloric diets in mash form, with various protein sources. In the control group (C), soybean meal (SBM) was the main source of dietary protein, whereas the experimental groups were fed diets containing 20% of RRC, HRC or FRC. Hydrobarothermal treatment and fermentation decreased the glucosinolate (GLS) content of RC, and fermentation reduced the concentration of phytate phosphorus (PP). In comparison with the RRC group, layers from the HRC and FRC groups were characterized by higher laying performance, comparable with that in group C. Irrespective of its physical form, RC added to layer diets adversely affected eggshell quality in all experimental groups, whereas albumen quality was highest in the FRC group. In comparison with group C, diets containing RRC, HRC and HRC led to a significant decrease in the content of saturated fatty acids (SFAs), an increase in the proportion of n-3 and n-6 polyunsaturated fatty acids (PUFAs) in the total FA pool in egg yolks, and a decrease in the n-6/n-3 PUFA ratio. The inclusion of RRC, HRC and FRC in layer diets decreased the activity of superoxide dismutase (SOD) in egg yolks, relative to group C. Group FCR eggs were characterized by the highest activity of catalase (CAT) and the lowest lipid peroxides LOOH concentration, compared with the remaining groups. The addition of RC to layer diets did not compromise the sensory quality of eggs, and eggs produced in group FRC received the highest overall score. It can be concluded that the inclusion of 20% RRC, HRC and FRC in layer diets does not compromise the sensory quality of eggs and has a beneficial influence on the FA profile and antioxidant potential of egg yolks. The use of FRC is recommended because it contributes to the highest laying performance, superior albumen quality and the highest sensory quality of eggs, relative to RRC and HRC.

Dietary rumen-protected choline supplementation regulates blood biochemical profiles and urinary metabolome and improves growth performance of growing lambs

This study aimed to assess the growth performance and blood metabolites, as well as metabolic profiles in the urine of lambs fed on dietary rumen-protected choline (RPC). Thirty-six Dorper × Hu lambs weighing approximately 20 kg were equally assigned to three groups, and fed on three diets supplemented with different RPC concentrations (0, 0.25% and 0.75%) for 45 days. Supplementation of RPC significantly increased average daily gain (ADG) and decreased feed-to-gain ratio (F/G) of lambs (p < 0.05). Dietary RPC was significantly associated with elevated plasma high-density lipoprotein (HDL) and suppressed low-density lipoprotein (LDL) levels when compared to the control group (p < 0.05). Moreover, concentrations of very-low-density lipoprotein (VLDL) exhibited an increasing trend (p = 0.065), whereas β-hydroxybutyrate (BHBA) levels decreased (p = 0.086) in plasma. Analysis of urine metabolome revealed that RPC supplementation significantly suppressed urinary concentrations of pyruvate (p < 0.05), while increased urinary concentrations of trimethylamine oxide, p-cresol, phenylacetylglycine and hippurate (p < 0.05). These findings suggest that RPC supplementation can promote weight gain, alter plasma lipid metabolism and modify urinary metabolome which is correlated with energy metabolism, lipid metabolism and intestinal microbial metabolism in lambs. In conclusion, based on our findings, we recommend 0.25% RPC as a supplement for growing lambs.

Choline and methionine supplementation in layer hens fed flaxseed: effects on hen production performance, egg fatty acid composition, tocopherol content, and oxidative stability

Choline is an essential nutrient in laying hen diets and is needed for the formation of phosphatidylcholine (PC), that serves as a rich source of long chain (≥20 C) n-3 fatty acids (FA) in eggs. Methionine (Met) is the first limiting amino acid in layer hen diets and serves as a lipotropic agent with antioxidant properties. The objectives of the current study is based on the hypothesis that choline and Met supplementation will enhance egg PC and n-3 FA status, lipid stability, and production indices in layer hens fed flaxseed. Ninety-six, 40-wk-old laying hens (W-36 White Leghorns) were randomly allocated to 4 treatment groups, with 6 replicates containing four hens per cage. Hens were fed corn-soybean meal-based diet containing 0% flaxseed (Control), 15/100 g flaxseed (Flax), Flax+50% more methionine requirement for W-36 White Leghorns (Flax+Met), or Flax+0.15g/100g choline chloride (Cho) (Flax+Cho). All experimental diets were isocaloric and isonitrogenous and fed for a period of 120 d. Egg production and egg mass (g/hen/d) was higher for Flax+Met and Flax+Cho when compared to Flax and Control (P < 0.05). Egg weight was greater (P < 0.05) among hens fed the Control and Flax+Cho diets compared to Flax diet. Feeding flaxseed to hens led to over 6-fold increase in total n-3 FA. Choline supplementation increased egg α-tocopherol content (P < 0.05) while reducing lipid oxidation products measured as thiobarituric acid reactive substances in egg yolk (P < 0.05). Neither Met nor Cho had any impact on docosahexaenoic (22:6 n-3) acid concentration in eggs from hens fed flaxseed. However, addition of Met and Cho to layer diets increased docosapentaenoic acid (22:5 n-3) levels in eggs from hens fed flaxseed (P < 0.05). The PC content was lower in Control and Flax+Met (P < 0.05) when compared to Flax+Cho group. No difference was found in total lipid or phosphatidylethanolamine content of eggs (P > 0.05). The results from the current study suggest that n-3 FA content of egg yolk can be greatly increased by feeding flaxseed but reduced egg production. However, dietary Met and Cho can improve production performance in hens fed flaxseed-containing diets. Addition of Cho to flaxseed increased in egg weight, yolk α-tocopherol levels, PC content and oxidative stability of eggs when compared to hens fed flaxseed. Met and choline could be used in flaxseed (>15%) to increase egg production and egg mas.

Comparative characterization of lipids and volatile compounds of Beijing Heiliu and Laiwu Chinese black pork as markers

Chinese black pork is preferred by consumers due to its unique organoleptic characteristics, which are closely related to lipids and volatiles. The primary aim of this study was to reveal key lipids and volatiles for the differentiation of Duroc × (Landrace × Yorkshire) (DLY), and Beijing Heiliu and Laiwu black (BHLB) pork. Here, lipid and volatile profiles were comprehensively characterized and compared using untargeted lipidomic and volatilomic analysis. The BHLB pork showed higher intramuscular fat content (p < 0.05). The content of total monounsaturated fatty acids, along with C16:1, C17:1, C18:1, and C20:1, was higher in BHLB pork compared with DLY pork (p < 0.05). Lipidomic analysis showed that DLY and BHLB pork significantly differed in lipids at the class and molecular levels. The BHLB pork had significantly more triglyceride and less lysophosphatidylcholine compared with DLY pork (p < 0.05). In positive and negative modes, 34 and 21 potential lipid markers, respectively, were selected for the discrimination of DLY and BHLB pork. In addition, volatilomic analysis showed that DLY and BHLB pork were well distinguished, and 13 volatiles were considered as potential discriminatory markers. Our findings provide a comprehensive lipidomic and volatilomic profiles characteristic of BHLB pork and will hopefully provide an important basis for the effective identification of Chinese black pork.

The enrichment of eggs with docosahexaenoic acid and eicosapentaenoic acid through supplementation of the laying hen diet

The enrichment and transformation of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) enriched phospholipids for eggs deserve attention. The aim of the present study was to elucidate the comparative effects of DHA and EPA enriched phospholipids and triacylglycerols on egg fortification by determining the fatty acid composition of egg yolk after intervention with fish oil (15 g/kg) and krill oil (15 and 30 g/kg) for three consecutive weeks. The results indicated that laying hens could incorporate over 300 mg DHA and EPA into one egg. Greater retention efficiency of DHA and EPA in eggs was observed in fish oil supplementation compared with krill oil at equivalent dietary levels. DHA and EPA were prone to locate at the sn-2 position of phosphatidylcholine. Consequently, fish oil possessed high DHA content and conversion rate, and krill oil could raise the proportion of DHA-containing phospholipids in eggs.

Perspective: The Potential Role of Circulating Lysophosphatidylcholine in Neuroprotection against Alzheimer Disease

Alzheimer disease (AD), the most common cause of dementia, is a progressive disorder involving cognitive impairment, loss of learning and memory, and neurodegeneration affecting wide areas of the cerebral cortex and hippocampus. AD is characterized by altered lipid metabolism in the brain. Lower concentrations of long-chain PUFAs have been described in the frontal cortex, entorhinal cortex, and hippocampus in the brain in AD. The brain can synthesize only a few fatty acids; thus, most fatty acids must enter the brain from the blood. Recent studies show that PUFAs such as DHA (22:6) are transported across the blood-brain barrier (BBB) in the form of lysophosphatidylcholine (LPC) via a specific LPC receptor at the BBB known as the sodium-dependent LPC symporter 1 (MFSD2A). Higher dietary PUFA intake is associated with decreased risk of cognitive decline and dementia in observational studies; however, PUFA supplementation, with fatty acids esterified in triacylglycerols did not prevent cognitive decline in clinical trials. Recent studies show that LPC is the preferred carrier of PUFAs across the BBB into the brain. An insufficient pool of circulating LPC containing long-chain fatty acids could potentially limit the supply of long-chain fatty acids to the brain, including PUFAs such as DHA, and play a role in the pathobiology of AD. Whether adults with low serum LPC concentrations are at greater risk of developing cognitive decline and AD remains a major gap in knowledge. Preventing and treating cognitive decline and the development of AD remain a major challenge. The LPC pathway is a promising area for future investigators to identify modifiable risk factors for AD.

Choline supplementation alters egg production performance and hepatic oxidative status of laying hens fed high-docosahexaenoic acid microalgae

The purpose of the current study was to investigate the effect of choline as a means of increasing docosahexaenoic acid (22:6 n-3, DHA) deposition in egg yolks of hens fed a high-DHA microalgae product. Fifty-six, 26-wk-old, White Leghorn hens were kept in individual cages and randomly allocated to 1 of 4 dietary treatments, each with 7 replicate groups of 2 hens (n = 7 per treatment). The experimental diets were corn and soybean meal based, with 0% microalgae (control), 1% microalgae and no additional choline chloride (Alg), and Alg plus choline chloride at 0.1% (Ch0.1) and 0.2% (Ch0.2). The feeding trial lasted 16 wk. The data were fit as a general linear mixed model to generate least square means in response to diet. Variables measured multiple times during the study were fit as repeated measures. Using orthogonal contrasts, Alg was compared to control, and Ch0.1 and Ch0.2 were compared separately to Alg. Ch0.1 increased hen day egg production (P < 0.05) and Haugh unit (P < 0.05), and reduced feed conversion ratio (P < 0.05) compared to Alg, but Ch0.2 did not. Alg increased egg DHA (P < 0.001), phosphatidylethanolamine (P < 0.05), and phosphatidylcholine (P < 0.001) compared to control, but Ch0.1 or Ch0.2 had no effect compared to Alg (P > 0.05). In the liver, Alg increased lipid peroxidation products compared to control (P < 0.01), and Ch0.1 reduced them compared to Alg (P < 0.01). Both Ch0.1 and Ch0.2 increased hepatic concentrations of γ- (P < 0.05; P < 0.001) and α-tocopherol (P < 0.01; P < 0.001), and Ch0.1 increased γ-tocopherol concentration in eggs compared to Alg (P < 0.05). The results from the current study suggest that supplemental choline chloride in hen diets containing microalgae can improve production performance and egg quality, and protect the liver from oxidative stress.

Metabolomic Evaluation of Scenedesmus sp. as a Feed Ingredient Revealed Dose-Dependent Effects on Redox Balance, Intermediary and Microbial Metabolism in a Mouse Model

Scenedesmus is a common green algae genus with high biomass productivity, and has been widely used in biofuel production and waste water management. However, the suitability and metabolic consequences of using Scenedesmus as an animal feed ingredient have not been examined in detail. In this study, the influences of consuming Scenedesmus on the metabolic status of young mice were investigated through growth performance, blood chemistry, and liquid chromatography-mass spectrometry (LC-MS)-based metabolomics. Compared to the control diet, feeding a diet containing 5% Scenedesmus improved growth performance while the diet containing 20% Scenedesmus suppressed it. Among common macronutrients-derived blood biochemicals, serum triacylglycerols and cholesterol levels were dramatically decreased by feeding the 20% Scenedesmus diet. Metabolomic analysis of liver, serum, feces, and urine samples indicated that Scenedesmus feeding greatly affected the metabolites associated with amino acid, lipid, purine, microbial metabolism, and the endogenous antioxidant system. The growth promotion effect of feeding the 5% Scenedesmus diet was associated with elevated concentrations of antioxidants, an expanded purine nucleotide cycle, and modified microbial metabolism, while the growth suppression effect of feeding the 20% Scenedesmus diet was correlated to oxidative stress, disrupted urea cycle, upregulated fatty acid oxidation, and an imbalanced lipidome. These correlations among Scenedesmus dietary inclusion rate, individual metabolite markers, and growth performance suggest the need to define the dietary inclusion rate threshold for using Scenedesmus and other microalgae supplements as feed ingredients, and also warrant further mechanistic investigations on the biological processes connecting specific constituents of Scenedesmus with the metabolic effects observed in this study.

Dual functions of eicosapentaenoic acid-rich microalgae: enrichment of yolk with n-3 polyunsaturated fatty acids and partial replacement for soybean meal in diet of laying hens

Microalgae (Nannochloropsis sp., NS), with high contents of eicosapentaenoic acid (EPA) and crude protein, may be one of the important n-3 polyunsaturated fatty acid (PUFA) sources and potential protein feed ingredient. The purposes of this study were to enrich yolk with n-3 PUFA by dietary EPA-rich NS supplementation and to evaluate whether it is feasible to partly substitute for soybean meal in laying hens diet. A total of 360 37-wk-old healthy Lohmann Brown laying hens, with similar laying rate and body weight, were randomly allotted to 5 groups (6 replicates, 12 birds/replicate) and fed 5 experimental diets (0, 1, 2, 4, and 8% NS) for 4 wk. The hen performance and egg quality (except yolk color) were not affected (P > 0.05) by the NS supplemental diets. Yolk color score was increased as NS supplementation in diets (P < 0.001), and peaked on about the seventh day in all NS supplemental groups. The concentration of total n-3 PUFA was increased (P < 0.001), while total n-6 PUFA and n-6/n-3 ratio were decreased (P < 0.001) in yolk with increasing NS levels in diets. The 8% NS group had highest docosahexaenoic acid (DHA) and total n-3 PUFA levels, reaching 111.6 mg DHA and 148.6 mg total n-3 PUFA per egg. Maximum DHA, total n-3 PUFA, very long-chain (LC-) n-3 PUFA, and LC-PUFA levels were all observed at day 13 of NS supplementation. In conclusion, dietary NS supplementation enriched yolk with n-3 PUFA (especially DHA) and enhanced yolk color score without adverse effects on performance and egg quality, and indicated the practical feasibility of partial replacement for soybean meal in laying hens diet.