Impact of microalgal feed supplementation on omega-3 fatty acid enrichment of hen eggs

Microalgae as a Sustainable Source of Antioxidants in Animal Nutrition, Health and Livestock Development

Microalgae are a renewable and sustainable source of bioactive compounds, such as essential amino acids, polyunsaturated fatty acids, and antioxidant compounds, that have been documented to have beneficial effects on nutrition and health. Among these natural products, the demand for natural antioxidants, as an alternative to synthetic antioxidants, has increased. The antioxidant activity of microalgae significantly varies between species and depends on growth conditions. In the last decade, microalgae have been explored in livestock animals as feed additives with the aim of improving both animals' health and performance as well as product quality and the environmental impact of livestock. These findings are highly dependent on the composition of microalgae strain and their amount in the diet. The use of carbohydrate-active enzymes can increase nutrient bioavailability as a consequence of recalcitrant microalgae cell wall degradation, making it a promising strategy for monogastric nutrition for improving livestock productivity. The use of microalgae as an alternative to conventional feedstuffs is becoming increasingly important due to food-feed competition, land degradation, water deprivation, and climate change. However, the cost-effective production and use of microalgae is a major challenge in the near future, and their cultivation technology should be improved by reducing production costs, thus increasing profitability.

Egg production, egg quality, and fatty acids profiles in eggs and tissues in Lohmann LSL lite hens fed algal oils rich in docosahexaenoic acid (DHA)

Enriching eggs with omega-3 fatty acids (n-3 FA), such as docosahexaenoic acid (DHA), is a well-accepted practice that benefits the egg industry and consumers. However, issues around cost, sustainability, and product acceptance have necessitated the search for alternatives to feeding hens fish oil for DHA enrichment. The effects of feeding 2 algal oils on egg production and DHA enrichment in eggs and selected tissues were investigated. The algal oils were: 1) OmegaPro (OPAO) standardized algal oil for DHA content and 2) Crude algal oil (CAO). A total of 400, 46-wk-old Lohmann LSL lite hens were housed in enriched cages (10 birds/cage) and allocated 5 diets (n = 8) for a 12-wk trial. The iso-caloric and -nitrogenous diets were a standard corn and soybean meal diet, standard plus 0.25 or 0.76% OPAO and standard plus 0.23 or 0.69% CAO; algal oils diets supplied similar DHA at each level. Egg production indices (hen day egg production, feed intake, FCR, egg weight, egg mass, and eggshell quality) were monitored for 10 wk. Diet samples were analyzed for fatty acids (FA) on wk 1, 6, and 12 and eggs on wk 4, 5, 6, 9, and 12. At the end of the trial, one hen/cage was weighed and dissected for liver, breast and thigh for FA and long bones for ash content analyses. Concentration of omega-6 to omega-3 FA ratio was 12.9, 6.64, 3.48, 6.96, and 3.59 for standard, 0.23 and 0.76% OPAO, 0.25 and 0.69% CAO, respectively. Algal oils increased (P ≤ 0.046) eggshell thickness linearly. The concentration of DHA in the eggs from the birds fed the standard, 0.23 and 0.76% OPAO, 0.25 and 0.69% CAO was 84, 195, 286, 183, and 297 mg/100g egg, respectively, and algal oils enriched eggs with DHA linearly and quadratically (P ≤ 0.01). In conclusion, algal oils increased the concentration of DHA in eggs and had no adverse effects on egg production and eggshell quality.

Enhancement of Rabbit Meat Functionality by Replacing Traditional Feed Raw Materials with Alternative and More Sustainable Freshwater Cladophora glomerata Macroalgal Biomass in Their Diets

Today's challenges in the animal husbandry sector, with customers' demand for more beneficial products, encourage the development of strategies that not only provide more sustainable production from the field to the table but also ensure final product functionality. Thus, the current research was aimed at replacing some traditional feed raw materials in rabbit diets with C. glomerata biomass to improve the functionality of meat. For this purpose, thirty weaned (52-d-old) Californian rabbits were assigned to 3 dietary treatments: standard compound diet (SCD), SCD + 4% C. glomerata (CG4), and SCD + 8% C. glomerata (CG8). At the end of the feeding trial, 122-d-old rabbits were slaughtered, longissimus dorsi (LD) and hind leg (HL) muscles were dissected post-mortem, and moisture, protein, and lipid profiles were determined. Results revealed that CG4 treatment can increase protein (22.17 g/kg), total (192.16 g/kg) and essential (threonine, valine, methionine, lysine, and isoleucine) amino acid levels in rabbit muscles. Both inclusions gradually reduced fat accumulation in muscles (CG8 < CG4 < SCD) but improved the lipid profile's nutritional value by decreasing saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) and increasing polyunsaturated fatty acids (PUFA). As the dose of C. glomerata increased, the level of lipid oxidation decreased. Biomass supplementation enhanced PUFA/SFA and h/H levels while decreasing thrombogenicity index (TI) and atherogenic index (AI) levels in rabbit muscles, potentially contributing to the prevention of heart disease. Overall, dietary supplementation with C. glomerata biomass may be a more beneficial and sustainable nutritional approach to functionally enhancing rabbit meat.

Evaluation of Phenolic Compounds and Pigments in Freshwater Cladophora glomerata Biomass from Various Lithuanian Rivers as a Potential Future Raw Material for Biotechnology

Freshwater macroalgae produces a wide range of bioactive compounds, and interest in utilizing its biomass is growing rapidly. Meanwhile, exploiting renewable sources for biomass collection could lead to more sustainable biotechnological chains. The aim of this study was to investigate Cladophora glomerata biomass from Lithuanian rivers as a potential raw material for biotechnology. For this reason, phenolic compound profiles, antioxidant activity and pigment concentrations were determined in macroalgal biomass samples collected from the following four Lithuanian rivers: Dubysa (B1), Šventoji (B2), Nevėžis (B3) and Jūra (B4). The highest total phenolic compound content was determined in B3 (1.32 mg GAE/g). Three phenolic acids were identified, namely gallic (12.94–35.13 µg/g), p-hydroxybenzoic (23.97–29.05 µg/g) and p-coumaric (1.79–6.46 µg/g). The results indicate significant C. glomerata antioxidant activity; the highest reducing power reached 0.737 AU (B3), the total antioxidant content was 1.47 mg Trolox/g (B3), DPPH and ABTS radical scavenging was 11.09% (B3) and 97.86% (B1) and FRAP activity 20.86 µmol/L (B3). The content of pigments ranged from 0.56-0.74, 0.39–0.57, 0.17–0.23 to 0.11–0.17 mg/g in chlorophyll a, b, carotenoids, and lutein, respectively. To conclude, C. glomerata macroalgal biomass may have the potential to act as a functional raw material, as several groups of bioactive compounds and antioxidant activities were observed.

Enriching table eggs with n-3 polyunsaturated fatty acids through dietary supplementation with the phototrophically grown green algae Nannochloropsis limnetica: effects of microalgae on nutrient retention, performance, egg characteristics and health parameters

The fatty acid content of microalgae, especially the high content of omega-3 fatty acids such as eicosapentaenoic acid (EPA, C20:5) and docosahexaenoic acid (DHA, C22:6), could enrich eggs when fed to laying hens. Moreover, the properties and bioactive components of omega-3 fatty acids could positively influence the health and production performance of laying hens. In this study, the effects of dried Nannochloropsis limnetica inclusions in diets on yolk omega-3 fatty acid content, laying hen performance, nutrient retention, intestinal morphometry and systemic inflammatory markers were measured. A total of 240 twenty-five-wk-old laying hens were randomly assigned to 5 treatments distributed among 30 pens. Treatment A received the reference diet, while diets in treatments B, C, and D contained the control diet with 1, 2, and 3% microalgae added, respectively. In treatment E, a portion of ingredients of the control diet was replaced with rapeseed meal to induce a mild nutritional challenge, along with an inclusion of 3% microalgae. Compared to the control group the rate of lay increased by approximately 5% (P = 0.039) when birds were fed 2 or 3% microalgae. Furthermore, inclusion of 2 and 3% microalgae resulted in higher feed intake compared to the control group (126, 125, and 119 g/hen/d respectively; P = 0.001). Other performance parameters such as nutrient retention and egg characteristics were not affected by the dietary treatments. The EPA and DHA content of the yolk increased with increasing microalgae inclusion level (P < 0.001). A 2% algal inclusion resulted in 58.3 (EPA) and 603 (DHA) mg per 100 g dry yolk, respectively. Plasma haptoglobin levels of laying hens in both treatments receiving 3% microalgae were almost 3 times lower compared to the control group (1.25 and 1.62 vs. 5.60; P < 0.001), regardless of the inclusion of rapeseed in the diet. Based on these results, it can be concluded that the inclusion of N. limnetica enriches the egg yolk without negatively affecting the performance of laying hens and egg characteristics. Due to the positive effect on feed intake, microalgae in the diet provide nutritional benefits for laying hens. However, the positive effects of microalgae, especially on the health of laying hens, warrants further research.

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.

Microalgal-based feed: promising alternative feedstocks for livestock and poultry production

There is an immediate need to identify alternative sources of high-nutrient feedstocks for domestic livestock production and poultry, not only to support growing food demands but also to produce microalgae-source functional foods with multiple health benefits. Various species of microalgae and cyanobacteria are used to supplement existing feedstocks. In this review, microalgae have been defined as a potential feedstock for domestic animals due to their abundance of proteins, carbohydrates, lipids, minerals, vitamins, and other high-value products. Additionally, the positive physiological effects on products of animals fed with microalgal biomass have been compiled and recommendations are listed to enhance the assimilation of biomolecules in ruminant and nonruminant animals, which possess differing digestive systems. Furthermore, the role of microalgae as prebiotics is also discussed. With regards to large scale cultivation of microalgae for use as feed, many economic trade-offs must be considered such as the selection of strains with desired nutritional properties, cultivation systems, and steps for downstream processing. These factors are highlighted with further investigations needed to reduce the overall costs of cultivation. Finally, this review outlines the pros and cons of utilizing microalgae as a supplementary feedstock for poultry and cattle, existing cultivation strategies, and the economics of large-scale microalgal production.

Microalgal Cell Biofactory-Therapeutic, Nutraceutical and Functional Food Applications

Microalgae are multifaceted photosynthetic microorganisms with emerging business potential. They are present ubiquitously in terrestrial and aquatic environments with rich species diversity and are capable of producing significant biomass. Traditionally, microalgal biomass is being used as food and feed in many countries around the globe. The production of microalgal-based bioactive compounds at an industrial scale through biotechnological interventions is gaining interest more recently. The present review provides a detailed overview of the key algal metabolites, which plays a crucial role in nutraceutical, functional foods, and animal/aquaculture feed industries. Bioactive compounds of microalgae known to exhibit antioxidant, antimicrobial, antitumor, and immunomodulatory effects were comprehensively reviewed. The potential microalgal species and biological extracts against human pathogens were also discussed. Further, current technologies involved in upstream and downstream bioprocessing including cultivation, harvesting, and cell disruption were documented. Establishing microalgae as an alternative supplement would complement the sustainable and environmental requirements in the framework of human health and well-being.

Biotechnological production of lipid and terpenoid from thraustochytrids

As fungus-like protists, thraustochytrids have been increasingly studied for their faster growth rates and high lipid content. In the 1990s, thraustochytrids were used as docosahexaenoic acid (DHA) producers for the first time. Thraustochytrids genera, such as Thraustochytrium, Schizochytrium, and Aurantiochytrium have been developed and patented as industrial strains for DHA production. The high DHA yield is attributed to its unique and efficient polyketide-like synthase (PKS) pathway. Moreover, thraustochytrids possess a completed mevalonate (MVA) pathway, so it can be used as host for terpenoid production. In order to improve strain performance, the metabolic engineering strategies have been applied to promote or disrupt intracellular metabolic pathways, such as genetic engineering and addition of chemical activators. However, it is difficult to realize industrialization only by improving strain performance. Various operation strategies were developed to enlarge the production quantities from the laboratory-scale, including two-stage cultivation strategies, scale-up technologies and bioreactor design. Moreover, an economical and effective downstream process is also an important consideration for the industrial application of thraustochytrids. Downstream costs accounts for 20-60% of the overall process costs, which represents an attractive target for increasing the cost-competitiveness of thraustochytrids, including how to improve the efficiency of lipid extraction and the further application of biomass residues. This review aims to overview the whole lipid biotechnology of thraustochytrids to provide the background information for researchers.

Microalgae as source of functional ingredients in new-generation foods: challenges, technological effects, biological activity, and regulatory issues

Microalgae feasibility as food ingredients or source of nutrients and/or bioactive compounds and their health effects have been widely studied. This review aims to provide an overview of the use of microalgae biomass in food products, the technological effects of its incorporation, and their use as a source of health-promoting bioactive compounds. In addition, it presents the regulatory aspects of commercialization and consumption, and the main trends and market challenges Microalgae have stood out as sources of nutritional compounds (polysaccharides, proteins, lipids, vitamins, minerals, and dietary fiber) and biologically active compounds (asthaxanthin, β-carotene, omega-3 fatty acids). The consumption of microalgae biomass proved to have several health effects, such as hypoglycemic activity, gastroprotective and anti-steatotic properties, improvements in neurobehavioral and cognitive dysfunction, and hypolipidemic properties. Its addition to food products can improve the nutritional value, aroma profile, and technological properties, with important alterations on the syneresis of yogurts, meltability in cheeses, overrun values and melting point in ice creams, physical properties and mechanical characteristics in crisps, and texture, cooking and color characteristics in pastas. However, more studies are needed to prove the health effects in humans, expand the market size, reduce the cost of production, and tighter constraints related to regulations.

Comprehensive Lipidomics Analysis Reveals the Effects of Different Omega-3 Polyunsaturated Fatty Acid-Rich Diets on Egg Yolk Lipids

Dietary supplementation with omega-3 polyunsaturated fatty acids (n-3 PUFAs) for laying hens enriches eggs with these essential fatty acids. However, the enrichment patterns and changes to intact lipids in egg yolk have not been sufficiently revealed. Herein, egg yolk lipids from hens fed with diets supplemented with flaxseed, Schizochytrium sp. residue, or their mixture were comprehensively analyzed using ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). A total of 335 individual lipid species covering 23 (sub)classes were identified and quantified. Distinct n-3 PUFA-lipid profiles were revealed among different groups. Dietary α-linolenic acid (ALA) was mainly deposited in the TAG fraction, whereas synthesized or preformed docosahexaenoic acid (DHA) predominantly existed in the glycerophospholipid form. Furthermore, different lipid species were identified and related lipid pathways after dietary supplementation were analyzed. Collectively, these findings provide us with new knowledge for production, nutritional evaluation, authentication, and application of n-3 PUFA-enriched eggs.

The role of microalgae in the bioeconomy

The bioeconomy is a new and essential paradigm for reducing our dependence on natural resources and responding to the environmental threats that the Earth is currently facing. In this regard, microalgae offer almost unlimited possibilities for developing a modern bioeconomy given their metabolic flexibility and high biomass output rates, even when produced under harsh conditions, such as when treating wastewaters or using flue gases. In this article, the microalgal contribution to important economic activities such as the production of food and feed, cosmetics and health-related compounds is reviewed. Moreover, potential contributions of microalgae to emerging sectors are discussed, as in the production of biomaterials, agriculture-related products, biofuels and provision of services such as wastewater treatment and the clean-up of industrial gases. The different microalgal production technologies have also been analyzed to identify the main bottlenecks affecting microalgal use in different applications. Finally, the major challenges facing microalgal biotechnology in enlarging its contribution to the bioeconomy are evaluated, and future trends discussed.

Lipidomic characterization of omega-3 polyunsaturated fatty acids in phosphatidylcholine and phosphatidylethanolamine species of egg yolk lipid derived from hens fed flaxseed oil and marine algal biomass

Membrane phospholipids, including phosphatidylcholine (PC) and phosphatidylethanolamine (PE), consist of distinct fatty acids occupying the sn-1 and sn-2 positions, reflecting the highly regulated nature of lipid biosynthesis. However, little is known about the influence of dietary lipids on the positional nature of fatty acids in tissues, including the enrichment of omega-3 polyunsaturated fatty acid (PUFA) in chicken egg yolk phospholipids. This study was undertaken to characterize the PC and PE species in egg lipids derived from Lohmann hens (n=10/treatment) randomly allocated to either a control (no supplementation), a flaxseed oil (FO) or a marine algal oil (MA) diet. Each of the FO or MA diets supplied three levels of total omega-3 PUFA (0.20, 0.40 and 0.60% of diet) that were provided for 6 weeks. A combination of multiplexed mass spectrometry (MS) experiments are used to determine total, isobaric, and position molecules for PC and PE in egg yolk. The distribution of phospholipids in the yolk was predominantly PC over PE (~72 vs. 23%, respectively) across treatments. The longer chain PUFA existed in the sn-2 position in the PC and PE. Although docosahexaenoic acid (22:6) formed isomers with fatty acids 16:0, 18:0 and 18:1; it was preferentially enriched in the egg in combination with 16:0 with both the FO and MA-fed groups in both lipid pools. All 22:6-containing isomers were enriched by ~2-fold more (P < 0.0001) with MA than FO, however, all isomers exhibited a plateau with the FO-fed group. In addition, the MS analyses of PCs revealed several isobaric species containing eicosapentaenoic acid (EPA, 20:5), however, in the PE, EPA formed only one isomer (i.e. in combination with 16:0). These results may assist to elucidate potential aspects regulating the limited enrichment of omega-3 PUFA, particularly EPA and docosahexaenoic acid (22:6) in chicken eggs.

Algal Oil as Source of Polyunsaturated Fatty Acids in Laying Hens Nutrition: Effect on Egg Performance, Egg Quality Indices and Fatty Acid Composition of Egg Yolk Lipids

The aim of this study was to evaluate the effect of algal oil with very high level of docosahexaenoic acid (DHA, C22:6n-3) used as fat source in the diet for laying hens, on egg yolk lipids fatty acid composition, as well as egg production and egg quality indices, in comparison with other dietary fat sources. The experiment was carried out on 168 ISA Brown hens (25 to 60 wks of age), allocated to 7 groups of 12 replicates (cages), with two birds in each cage. The experimental diets were supplemented with 2% of different fat sources, i.e. soybean oil (SO), coconut oil (CO), rapeseed oil (RO), linseed oil (LO), camelina oil (CAO), fish oil (FO), or algal oil (AO). Laying performance indices, i.e. egg production, mean egg weight, feed intake, feed conversion ratio, or egg and eggshell quality parameters were not affected by used fat sources (P>0.05). Dietary fat sources significantly influenced on egg yolk lipids fatty acids composition. Thus, AO addition caused some changes in the yolk lipid profile that were favorable from the dietary perspective, i.e., increased concentration of eicosapentaenoic acid (EPA) and DHA (P<0.05). However, boiled eggs from hens fed a diet with AO were characterized by an inferior flavour and taste to those from other groups. In conclusion, the results of this experiment, have shown that the use of AO in the laying hens nutrition is an efficient way to increase the deposition of n-3 long chain polyunsaturated fatty acids (n-3 LCPUFAs) in eggs, without negative effect on egg performance, however further researches, aiming to establish optimal AO dietary level that does not adversely affect the organoleptic properties of eggs, are needed.

Time course of nutritional and functional property changes in egg yolk from laying hens fed docosahexaenoic acid-rich microalgae

Marine microalgae (MA) has received wide attention as a promising source of omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) enrichment in animal products to improve the health status and wellbeing of the consumers. This study evaluated dynamic changes in n-3 LC-PUFA, color, and functional properties as well as atherogenic and thrombogenic health lipid indices of egg yolk from hens fed graded levels (0, 0.5, and 1.0%) of docosahexaenoic acid (DHA)–rich MA (Aurantiochytrium sp.) during a 56-D feeding period. Egg freshness parameters and yolk lipid oxidative stability were also measured after 0, 14, and 28 D of refrigerated storage. The hen performance and egg quality (except for yolk color) were not affected (P > 0.05) by MA supplementation. Docosahexaenoic acid contents in yolk from hens fed 1.0% MA increased quadratically with feeding time with a plateau at about 30 D (P < 0.05). Afterward, the DHA content leveled off to a constant value (946.3 mg/100 g yolk) with the n-6/n-3 ratio at 3.5: 1. Dietary inclusion of 1.0% of MA also significantly decreased the atherogenic and thrombogenic indices of yolk lipid (P < 0.05). Because the microalgal carotenoids incorporated into egg yolk, the L∗ value of yolk from hens fed MA decreased whereas a∗ value increased (P < 0.05), corresponding to yolk Roche color scores. As expected, there were no significant changes in yolk functional properties (e.g., viscosity and emulsifying activity) related to DHA enrichment (P > 0.05). Microalgal carotenoids enrichment also helped attenuate fatty acid oxidation of the DHA-enriched yolk and increase their lipid oxidative stability. In conclusion, dietary supplementation with up to 1.0% of MA significantly increased DHA contents with more health-promoting n-6/n-3 ratio and atherogenic and thrombogenic indices, as well as more intense yolk color within consumers' acceptability, and the feeding strategy had a minimal impact on yolk physical and functional properties or oxidative stability during subsequent refrigerated storage.

Biofortification of Hens Eggs with Polyunsaturated Fatty Acids by New Dietary Formulation: Supercritical Microalgal Extract

The aim of the study was to evaluate the effect of Spirulina platensis, formulation containing microalgal extract, post-extraction residue, and formulation without algal extract (containing only emulsifier) on the content of FAs in the eggs of laying hens. The experiment was conducted on 90 laying hens (ISA Brown) as a completely randomized design. Hens were assigned to five experimental groups (six replicates). The FAs content in eggs was determined after 30, 60, 90, and 120 days of the experiment. There were no statistically significant differences in FA profiles after 30 days of the experiment. It was shown that after 60, 90, and 120 days of the experiment, the investigated additives had a significant impact on the content of such acids as: dodecanoic acid (C12:0), C15:0, nonadecanoic acid (C19:0), myristoleic acid (C14:1 n-5), α-linolenic acid (ALA, C18:3 n-3), DPA, C20:2 n-6, and decosahexaenoic acid (DHA C22:6 n-6). There were also significant differences in total PUFA n-3, PUFA n-6, and n-6/n-3 ratio in eggs. The obtained results suggest that the use of algae extract and emulsifier in laying hens nutrition has the greatest impact on the FA profile in the eggs.

Can human nutrition be improved through better fish feeding practices? a review paper

Achieving Sustainable Development Goal 2 of zero hunger and malnutrition by 2030 will require dietary shifts that include increasing the consumption of nutrient dense foods by populations in low- and middle-income countries. Animal source foods are known to be rich in a number of highly bioavailable nutrients that otherwise are not often consumed in the staple-food based diets of poorer populations throughout the world. Fish is the dominant animal source food in many low- and middle-income countries in the global south and is available from both fisheries and aquaculture. Consumers often perceive that wild caught fish have higher nutritional value than fish produced through aquaculture, and this may be true for some nutrients, for example omega-3 fatty acid content. However, there is potential to modify the nutritional value of farmed fish through feeds and through production systems, illustrated by the common practice of supplementing omega-3 fatty acids in fish diets to optimize their fatty acid profile. This manuscript reviews the evidence related to fish feeds and the nutritional composition of fish with respect to a number of nutrients of interest to human health, including iron, zinc, vitamins A and D, selenium, calcium, and omega-3 fatty acids, with low- and middle-income country populations in mind. In general, we find that the research on fortification of fish diet particularly with vitamins and minerals has not been directed toward human health but rather toward improvement of fish growth and health performance. We were unable to identify any studies directly exploring the impact of fish feed modification on the health of human consumers of fish, but as nutrition and health rises in the development agenda and consumer attention, the topic requires more urgent attention in future feed formulations.

Comparative effects of dietary microalgae oil and fish oil on fatty acid composition and sensory quality of table eggs

This study was conducted to investigate the comparative effects of dietary supplementation with microalgae oil or fish oil on fatty acid composition, sensory quality, and overall acceptability of table eggs. A total of six hundred thirty, 30-week-old, Hy-Line Brown laying hens were allocated to 7 dietary treatments. Layers were fed with a control diet or the control diet supplemented with graded levels of docosahexaenoic acid (DHA; 1.25, 2.50, and 5.00 mg/g feed) derived from microalgae oil or fish oil. The feeding trial lasted 10 wk. Enrichment of eggs with DHA by dietary supplementation with microalgae oil or fish oil enhanced yolk DHA and total n-3 polyunsaturated fatty acid (PUFA) enrichment and reduced n-6-to-n-3 ratio in a dose-response manner, whereas the efficiency decreased (P < 0.05). The overall efficiency of DHA incorporation into eggs was similar for the 2 sources (P > 0.05). In comparison with fish oil, dietary microalgae oil supplementation resulted in higher scores for egg flavor and overall acceptability, both of which declined linearly in response to DHA supplementation (P < 0.05). Among the aroma and flavor characteristics, fishy aroma and flavor scores increased linearly and quadratically (P < 0.05) in response to dietary DHA supplementation, and egg aroma and flavor and milky flavor scores decreased linearly (P < 0.05). The results from partial least squares analysis showed that fishy flavor and aroma were closely associated with DHA, α-linolenic acid, and total n-3 PUFA, and oleic acid, arachidonic acid, and dihomo-gamma-linolenic acid were more related to egg aroma and flavor. The results suggested that microalgae oil would be more promising for egg DHA enrichment owing to better sensory quality of the resultant eggs.

Assessment of microalgae as a new feeding additive for fruit fly Drosophila melanogaster

Animal food wastes are a concern due to the large amounts of commercial food required for model animals during the biological and biomedical research. Searching for sustainable food alternatives with negligible physiological effects on animals is critical to solve or reduce this challenge. Microalgae have been demonstrated to be suitable for both human consumption and animal feed. In this study, the possibility of using Chlorella vulgaris and Senedesmus obliquus as a feed replacement to Drosophila melanogaster, one of the fly models commonly used in biomedical studies, was investigated. Characteristics including the fly locomotor activity, motor pattern, feeding behavior, lifespan and body weight were assessed. Results showed that compared to control, the flies fed on 80% microalga (80-flies) in the total weight (w/w) had the double increased apparent step size, while both 60-flies and 80-flies exhibited longer travel distances (60%: 27.77 ± 1.99 cm; 80%: 31.50 ± 3.70 cm) most likely due to the starvation and varied serotonin levels in flies fed on high percentages microalgae. Subsequently, 40-flies exhibited less optimal growth performance with decreased body weights (0.51 ± 0.006 mg vs 0.60 ± 0.005 mg for control) and shorter mean lifespan (36 days vs 55.8 days for control. However, 20-flies showed no statistical differences in all parameters tested with respect to control flies, indicating that 20% microalgae treatment did not greatly change the primary food component such as carbohydrate which might play a critical role in fly performance. Therefore, the inclusion of 20% microalgae could be an alternative to fly standard food without compromising fly physiological performance.

Potential Industrial Applications and Commercialization of Microalgae in the Functional Food and Feed Industries: A Short Review

Bioactive compounds, e.g., protein, polyunsaturated fatty acids, carotenoids, vitamins and minerals, found in commercial form of microalgal biomass (e.g., powder, flour, liquid, oil, tablet, or capsule forms) may play important roles in functional food (e.g., dairy products, desserts, pastas, oil-derivatives, or supplements) or feed (for cattle, poultry, shellfish, and fish) with favorable outcomes upon human health, including antioxidant, anti-inflammatory, antimicrobial, and antiviral effects, as well as prevention of gastric ulcers, constipation, anemia, diabetes, and hypertension. However, scale up remains a major challenge before commercial competitiveness is attained. Notwithstanding the odds, a few companies have already overcome market constraints, and are successfully selling extracts of microalgae as colorant, or supplement for food and feed industries. Strong scientific evidence of probiotic roles of microalgae in humans is still lacking, while scarce studies have concluded on probiotic activity in marine animals upon ingestion. Limitations in culture harvesting and shelf life extension have indeed constrained commercial viability. There are, however, scattered pieces of evidence that microalgae play prebiotic roles, owing to their richness in oligosaccharides-hardly fermented by other members of the intestinal microbiota, or digested throughout the gastrointestinal tract of humans/animals for that matter. However, consistent applications exist only in the dairy industry and aquaculture. Despite the underlying potential in formulation of functional food/feed, extensive research and development efforts are still required before microalgae at large become a commercial reality in food and feed formulation.

Current feeding strategies to improve pork intramuscular fat content and its nutritional quality

Pork, one of the most consumed meats worldwide, has been facing major challenges regarding its low sensory quality and unhealthy image of fat. This chapter addresses current feeding strategies to ameliorate pork sensory attributes and nutritional quality by increasing intramuscular fat deposition and improving fatty acid composition, respectively. Dietary protein reduction, alone or combined with some components, contributes to satisfy consumer requirements and enhances the competitiveness of the meat industry with higher pork quality and lower production costs. In addition, feeding sources of n-3 polyunsaturated fatty acids to pigs, mainly from marine origin (rich in eicosapentaenoic and docosahexaenoic acids), increases their content in pork, thus improving the health value of its fatty acid profile. In the near future, the inclusion of microalgae and seaweeds in feed represents a promising approach for the maintenance and development of the livestock sector, as an environmental friendly alternative to balance food and feed industries.

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.

Variability in nutrient composition and in vitro crude protein digestibility of 16 microalgae products

The chemical composition of 16 microalgae products of four genera, Arthrospira (n = 2), Chlorella (n = 8), Nannochloropsis (n = 4) and Phaeodactylum (n = 2), was assayed to evaluate the intra- and inter-genera variation of nutrient profiles of commercial microalgae products. Crude protein was the main component in all genera, followed by ether extract and crude ash. Mean crude protein concentrations were 690, 502, 431 and 446 g/kg dry matter, and mean ether extract concentrations were 63, 157, 188 and 113 g/kg dry matter for Arthrospira, Chlorella, Nannochloropsis and Phaeodactylum respectively. However, there was considerable inter- and intra-genera variation. The concentration of α-linked glucose was low (0-143 g/kg dry matter). There was high variation between and within genera in the crude ash concentration (22-237 g/kg dry matter), which was also observed for the mineral composition. In contrast to the crude protein concentration, the amino acid composition of the protein (g amino acid/16 g N) was less variable. The investigated samples possessed high concentrations of Glx, Asx and Leu, and low concentrations of Cys and Met. The mean concentration of non-protein nitrogen compounds was highest in Phaeodactylum (110 g/kg dry matter) and lowest in Nannochloropsis (47 g/kg dry matter) products, and as with proximate nutrients, high variability between and within genera was observed. In vitro crude protein digestibility varied between 54% (non-cell-disrupted Nannochloropsis) and 84% (cell-disrupted Chlorella). Inositol phosphate isomers were not detectable in any sample (concentration <1 μmol/g dry matter). The predominant fatty acids were C16:0 in Arthrospira products, C18:2 n-6+ C19:1 t7 and C18:3 n-3 in Chlorella products, and C20:5 n-3 in Nannochloropsis and Phaeodactylum products; however, the relative proportions of fatty acids varied within genera. Commercially available microalgae products appear to be valuable alternative food and feed products. However, because of the high variability in nutrient profiles, attention should be given to the analytical characterization of the products.

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

The aim of this study was to evaluate the effect of dietary phospholipid supplementation on laying hen performance, egg quality, and the fatty acid profile of egg yolks from hens fed a 2% Schizochytrium powder diet. Three-hundred-sixty 28-wk-old Hy-line W-36 laying hens were randomly allocated to one of the 5 dietary treatments, each treatment with 6 replicates of 12 birds each. All diets included 2% Schizochytrium powder (docosahexaenoic acid [DHA], 137.09 mg/g). The control group was not supplemented with any additional phospholipids, whereas the other 4 experimental diets were supplemented with 1,000 mg/kg choline (CHO), 1,000 mg/kg monoethanolamine (MEA), 1,000 mg/kg lysophosphatidylcholine (LPC), or 500 mg/kg LPC + 500 mg/kg MEA (LPC + MEA). The experimental diets were isocaloric (metabolizable energy, 11.15 MJ/kg) and isonitrogenous (crude protein, 16.60%). The feeding trial lasted 28 days. Laying hen performance and egg quality were not affected (P > 0.05) by the diets used. The monounsaturated fatty acid (MUFA) level was reduced in the LPC group at d 28 (P < 0.01), whereas the polyunsaturated fatty acid (PUFA) level was increased (P < 0.05). The omega-6 (n-6) PUFA level of the egg yolks in the LPC group had a trend to increase in comparison to the control (P = 0.07). The CHO and LPC groups had higher omega-3 (n-3) PUFA and DHA levels and lower n-6/n-3 ratios than the other groups at d 28 (P < 0.01). The DHA content in egg yolk reached a plateau after the laying hens consumed the experimental diets for 14 days, and higher yolk DHA contents were observed in the CHO and LPC groups as compared with the other groups at d 14. It was concluded that dietary choline supplementation for more than 14 d enhanced egg yolk enrichment with n-3 PUFA and DHA when laying hen diets were supplemented with 2% Schizochytrium powder. All the diets had no adverse effect on hen performance, egg quality, or egg components under the experimental condition.

Effect of dietary inclusion of sugar syrup on production performance, egg quality and blood biochemical parameters in laying hens

The effects of dietary inclusion of sugar syrup on quality of egg, cholesterol level, production performance, serum total protein and blood biochemical parameters were evaluated in laying hens. A total of 300 commercial Lohmann LSL hens (30 weeks of age) were randomly distributed into 3 dietary treatments which consisted of a normal corn diet containing corn-soy and 2 diets containing 5% and 10% sugar syrup. Each treatment was replicated 5 times (n = 20). Egg production, feed intake, body weight and egg weight of laying hens fed different diets were recorded. The experiment lasted for 20 weeks. The Haugh unit scores of hens fed diets with sugar syrup were significantly increased (P < 0.05) compared with the control treatment. The sugar syrup had no significant effect on liver enzymes, total protein, blood glucose and creatinine in all treatments. The eggs laid by hens fed sugar syrup diets had lower cholesterol level (P < 0.05) compared with those laid by hens fed the control diet. Electrophoresis analysis showed that comparable electrophoretic patterns were noticed between serum proteins of treatment groups. From the results, it can be concluded that sugar syrup diets and corn diets have similar effects on feed intake, body weight, production of eggs and blood biochemical parameters in layer hens, which suggests sugar syrup can be used as an energy source for replacing part of corn in poultry layer diets.

Effect of marine by-product meals on hen egg production parameters, yolk lipid composition and sensory quality

The effect of including 5% marine by-product meals in feeds of laying hens on egg production, composition and sensory characteristics was tested. Marine by-product meals were prepared using two methods: (i) cooking (100°C/10 min) followed by drying (60°C/24 hr) or (ii) grinding followed by drying. The raw materials used for meal production were scallop or squid viscera, shrimp heads or whole mackerel. A total of 108 laying hens were allocated to nine diet treatments; one control diet (corn and soya bean based) and eight experimental diets, containing 95% of the control feed and 5% of the experimental meal for three weeks. Daily intake was higher in hens fed the dried mackerel and cooked shrimp meals. All the experimental treatments showed significantly higher concentration of n-3 HUFA in yolk reserves and phospholipids compared to the control (0.12-0.13 g per 100 g), especially those with scallop or squid prepared by both methods (0.53-0.95 g per 100 g). Scallop, squid and shrimp meal inclusion in the feed produced eggs with more astaxanthin (0.22 mg per 100 g) while this carotenoid was absent in the control and mackerel treatments. Visual evaluation of raw yolk colour increased with the inclusion of marine by-product meals with higher values in hens fed shrimp heads (13), followed by scallop viscera (11), squid viscera (9), and with similar values for mackerel and control (4). The taste, aroma, texture and colour of cooked eggs from different treatments were not statically different when evaluated by a panel of 60 untrained people. These results suggest that meals from marine by-products are a better alternative for improving egg yolk composition by increasing n-3 HUFA when compared to fishmeal as they also increase astaxanthin and yolk pigmentation without affecting egg sensory characteristics.

Effect of flaxseed oil and microalgae DHA on the production performance, fatty acids and total lipids of egg yolk and plasma in laying hens

The incorporation of omega-3 polyunsaturated fatty acids (PUFA) in the egg is dependent on both the transfer efficiency of preformed dietary omega-3 fatty acids to the eggs as well as endogenous PUFA metabolism and deposition. Employing an experimental design consisting of 70 Lohmann LSL-Classic hens (n=10/treatment) in a 6-week feeding trial, we examined the impact of graded levels of either flaxseed oil (alpha-linolenic acid, ALA) or algal DHA (preformed docosahexaenoic acid, DHA), each supplying 0.20%, 0.40% and 0.60% total omega-3s. The control diet was practically low in omega-3s. Study parameters included monitoring the changes of fatty acid contents in yolk, measures of hen performance, eggshell quality, total lipids and fatty acid contents of plasma. Data were analysed as a complete randomized design using Proc Mixed procedure of SAS. No significant differences were observed between treatments with respect to hen performance, eggshell quality and cholesterol content in plasma and egg yolk. Individual and total omega-3 PUFA in the yolk and plasma increased (P<0.0001) linearly as a function of total omega-3 PUFA intake. At the highest inclusion levels, DHA-fed hens incorporated 3-fold more DHA in eggs compared with ALA-fed hens (179±5.55 vs. 66.7±2.25mg/yolk, respectively). In both treatment groups, maximal enrichment of total n-3 PUFA was observed by week-2, declined by week-4 and leveled thereafter. In addition, accumulation of DHA in egg yolk showed linear (P<0.0001) and quadratic (P<0.05) effects for flaxseed oil (R²=0.89) and algal DHA (R²=0.95). The current data, based on defined level of total omega-3s in the background diet, provides evidence to suggest that exogenous as well as endogenous synthesis of DHA may be subject to a similar basis of regulation, and serve to highlight potential regulatory aspects explaining the limitations in the deposition of endogenously produced omega-3 LCPUFA.

Phytosterol structured algae oil nanoemulsions and powders: improving antioxidant and flavor properties

Phytosterol structured algae oil nanoemulsions and powders were obtained using a one-pot sonification strategy and followed by spray-drying. β-Sitosterol and γ-oryzanol co-structured microencapsulation is a technique for burying fishy odor and preventing oil oxidation.

Mortierella alpina feed supplementation enriched hen eggs with DHA and AA

Eggs enriched with long-chain polyunsaturated fatty acids (PUFAs) are considered an important nutrition source.