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

Effects of using microalgae in poultry diets on the production and quality of meat and eggs: a review

1. This review was conducted to examine the nutritional composition of microalgae and their effects as a feed ingredient in poultry diets, delving into their influence on the production and quality of meat and eggs. Data collection focused on peer-reviewed scientific articles, with no limitation on the temporal horizon.2. Regarding nutritional composition, the collected papers indicated that certain microalgae species have a rich nutritional composition, with approximately 50% of their biomass composed of proteins. They contain a high concentration of EPA and DHA, important fatty acids that are found in low concentrations in conventional feedstuffs, and the presence of carotenoids such as beta-carotene.3. Incorporating microalgae into the diet of poultry can improve performance variables, such as mortality, live weight and feed conversion rate. It promotes benefits in meat and egg quality, with reduced cholesterol, increased EPA and DHA, intensified colour and higher concentration of carotenoids.

Dietary Dunaliella salina microalgae enriches eggs with carotenoids and long-chain omega-3 fatty acids, enhancing the antioxidant and immune responses in heat-stressed laying hens

Introduction

Dunaliella salina (DS) is a prospective source of bioactive carotenoids, including beta-carotene, zeaxanthin, and omega-3 fatty acids. The effect of dietary supplementation of DS on the productive performance, immune response, and egg quality of heat-stressed laying hens has not been comprehensively studied. We investigated how dietary D. salina supplementation affects the deposition of bioactive carotenoids and omega-3 fatty acids in egg yolks of laying hens experiencing summer heat stress, as determined by the Temperature-Humidity Index (THI). The influence of D. salina supplementation on the productive performance, immune response, and antioxidant status of heat-stressed laying hens was assessed.

Methods

A total of 120 Elma-Brown laying hens were assigned to four dietary treatments with DS supplementation at 0 (control), 0.5, 1, and 1.5 g/kg of diet. The experiment lasted 60 days, during which eggs were collected at three time points: 15, 30, and 60 days from the start of the study.

Results and discussion

including DS at 1 g/kg improved egg production and feed conversion, with improved antioxidant status via a marked inhibitory effect on malondialdehyde in heat-stressed laying hens. Dietary 0.5 g/kg DS improved the immune response of heat-stressed laying hens compared to that of the control group. The highest dose of DS (1.5 g/kg diet) increased astaxanthin, zeaxanthin, lutein, and total carotenoids by 9.8%, 50.44%, 49.19%, and 84.21% (p < 0.05), respectively, and decreased β-carotene by 38.61% (p < 0.05), when compared with the control. Feeding DS to heat-stressed laying hens increased the concentrations of the long-chain Omega-3 (docosahexaenoic acid) in egg yolks; the dose of 0.5 g/kg diet for 15 d produced an increase in the DHA content by104.76% above the control group (p < 0.5). Feeding DS improved the nutritional indices of egg yolks, as egg yolks retained a high ratio of monounsaturated fatty acids (MUFA)/polyunsaturated fatty acids (PUFA)/saturated fatty acids, low thrombogenicity index (IT), low atherogenicity index (IA), and high hypocholesterolemic/hypercholesterolemic index (h/H). Feeding heat-stressed laying hens DS improved their productivity and antioxidant status, resulting in functional eggs enriched with bioactive carotenoids (astaxanthin, zeaxanthin, and lutein) and beneficial omega-3 fatty acids.

Effects of Dietary Schizochytrium Algae as ω-3 PUFA Source on the Egg-Laying Quail Performance, Serum Indexes, and Egg Yolk Fatty Acids Contents

The objective of this experiment is to investigate the effects of SAP or SAO as ω-3 PUFA raw materials on production performance, egg quality, serum immunity, serum lipids, and fatty acid deposition patterns in the eggs of laying quails. Chinese yellow-feathered quails served as the experimental subjects. A single-factor design was employed to randomly assign 1288 quails into four treatment groups, with seven replicates per treatment and 46 birds in each replicate. The groups included a control group (basal diet with no SAP), 1.6% SAP, 3.2% SAP, and 0.8% SAP + 0.3% SAO. The results indicate that: (1) Compared to the control group, the 0.8% SAP + 0.3% SAO group exhibited a reduction in daily egg-laying rate and egg mass, alongside an increased FCR; (2) the 3.2% SAP group enhanced egg yolk color, while the 1.6% SAP group reduced eggshell thickness, and the 0.8% SAP + 0.3% SAO group increased eggshell thickness; (3) compared to the control group, the 3.2% SAP group decreased total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) levels in serum; the addition of either the 3.2% SAP or the 0.8% SAP + 0.3% SAO group significantly elevated quail serum immunoglobulin M (IgM) levels (p < 0.05); (4) in comparison to the control group, the addition of SAP or with SAP increased the contents of monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), docosahexaenoic acid (DHA), and ω-3 PUFA in 56-day-old egg yolks while reducing the ω-6/ω-3 ratio (p < 0.05). These findings suggest that SAP as a source of ω-3 PUFA raw materials could improve quail health by improving lipid metabolism and immunity. 3.2% SAP was recommended as the optimal level to produce the enriched ω-3 PUFA quail eggs with the ω-3 PUFA ≥ 300 mg/100 g.

Supplementation of laying hens' feed with Schizochytrium powder and its effect on physical and chemical properties of eggs

Biofortification enhances dietary quality and nutritional value using traditional marine microalga species, particularly docosahexaenoic acid (DHA), which is an essential n-3 fatty acid for human health. Eggs are natural fortified candidates. This study aimed to investigate the effect of dietary Schizochytrium powder on egg productivity, egg nutritional content, and fatty acid levels in laying hens. Hy-Line Brown laying hens (n = 150) were uniformly assigned to five groups for 52 days. The control group received no supplements, whereas the other four experimental groups were provided with varied amounts of schizochytrium powder. The experimental feed contained isonitrogenous (16.60%) and isocaloric metabolizable energy, 36.69 MJ/kg components. No significant differences were observed (p > 0.05) on different parameters such as average daily feed intake, feed conversion ratio, egg weight, and shell thickness. Enriching eggs significantly increased α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and DHA levels (p < 0.001), while decreasing the n-6/-3 ratio in a dose-dependent manner, ensuring high quality and biological efficacy. A plateau point was maintained throughout the study period. In the first two weeks, increased DHA levels were observed in egg yolks when microalgae concentrations were elevated by 1%. The study found that powdered Schizochytrium limacinum served as a substitute for DHA in enhancing eggs with n-3 fatty acids.

Effect of Dietary Cold-Pressed Hempseed Cake Supplemented with Tomato Waste on Laying Hen Performance and Egg Yolk Lipid Profile and Antioxidant Status Before and After Storage

A ten-week study was conducted to investigate the effects of the dietary inclusion of HSC as a source of PUFAs together with a natural source of antioxidants such as DT or DTP on the performance of laying hens and egg quality, as well as the lipid profile, antioxidant content and oxidative stability of egg yolk before and after storage. A total of 96 laying hens (aged between 28 and 37 weeks) were divided into three groups of 32 birds each (eight replicate cages, four birds per cage) and were assigned randomly the following dietary treatments: a standard corn-soybean meal diet (C), a diet containing 20% hempseed cake and 4% dried whole tomato (HT) and a diet containing 20% hempseed cake and 4% dried tomato pomace (HTP). The incorporation of HSC and tomato waste (DT and DTP) into the diet of hens caused increases in feed intake (p < 0.05) and yolk color score without changing egg production, egg weight or feed conversion ratio (FCR). The HT and HTP diets ensured a lower content (p < 0.05) of cholesterol in the egg yolk but a higher content (p < 0.001) of n-3 FAs, especially of ALA (α-linolenic acid, 18:3n-3), EPA (eicosapentaenoic acid, 20:5n-3) and DHA (docosahexaenoic acid, 22:6n-3), which allowed for an increase in the hypo-/hypercholesterolemic FA ratio and a reduction in the n-6/n-3 FA ratio and TI (thrombogenicity index) value compared to those of C eggs. In addition, the inclusion of DT or DTP in the diet of laying hens increased the antioxidant content in the yolk, which led to an increase in the oxidative stability of the yolk lipids, evidenced by a decrease in the concentrations of MDA (malondialdehyde) in fresh eggs and those stored for 30 days at 4 °C. DTP exerted the most desirable effects because the egg yolk had the most intense color, the highest contents of n-3 FAs and natural antioxidants and the best oxidative stability of yolk lipids before and after egg storage. It was concluded that the simultaneous enrichment of the diet of laying hens with n-3 FAs and natural antioxidants (carotenoids, tocopherols and phenols), in addition to improving the color of the yolk, leads to eggs with a higher content of n-3 FAs and antioxidants, improved antioxidant activity and better PUFA stability during egg storage.

Application research and progress of microalgae as a novel protein resource in the future

Economic growth and health awareness spotlight opportunities and challenges in the food industry, particularly with decreasing arable land, climate change, dwindling freshwater resources, and pollution affecting traditional protein sources. Microalgae have emerged as a promising alternative, with higher protein content, better nutritional quality, and greater environmental resilience compared to conventional crops. They offer a protein balance comparable to meat, making them a sustainable protein source with health benefits like antioxidants, cardiovascular support, and anti-inflammatory properties. Improving the protein content of microalgae through optimized cultivation techniques is crucial to fully realize its potential as a novel food source. While there are already microalgae-based food products in the market, challenges remain in utilizing microalgal protein for widespread food production, emphasizing the need for further research. This review article explores the impact of microalgae culture conditions on protein content, the physicochemical and nutritional characteristics of microalgal protein, the health advantages of microalgal proteins and their derivatives, as well as research on separating and purifying microalgal proteins and their derivatives. It also delves into the current opportunities and obstacles of microalgal proteins and their derivatives as food, highlighting the potential for investigating the link between microalgal protein food and human health.

Potential and Metabolic Impacts of Double Enrichments of Docosahexaenoic Acid and 25-Hydroxy Vitamin D3 in Tissues of Broiler Chickens

BACKGROUND

Chicken may be enriched with 25-hydroxy D3 [25(OH)D3] and docosahexaenoic acid (DHA) to enhance the dietary intake of the public.

OBJECTIVES

Two experiments (Expt.) were conducted to determine the potential and metabolic impacts of enriching both DHA and 25(OH)D3 in the tissues of broiler chickens.

METHODS

In Expt. 1, 144 chicks (6 cages/treatment and 6 birds/cage) were fed a corn-soybean meal basal diet (BD), BD + 10,000 IU 25(OH)D3/kg [BD + 25(OH)D3], BD + 1% DHA-rich Aurantiochytrium (1.2 g DHA/kg; BD + DHA), or BD + 25(OH)D3+DHA for 6 wk. In Expt. 2, 180 chicks were fed the BD, BD + DHA-rich microalgal oil (1.5-3.0 g DHA/kg, BD + DHA), BD + DHA + eicosapentaenoic acid (EPA)-rich microalgae (0.3-0.6 g EPA/kg, BD + DHA + EPA), BD + DHA + 25(OH)D3 [6000 to 12,000 IU/kg diet; BD + DHA + 25(OH)D3], and BD + DHA + EPA + 25(OH)D3 for 6 wk.

RESULTS

Supranutrition of these 2 nutrients resulted in 57-62 mg DHA and 1.9-3.3 μg of 25(OH)D3/100 g of breast or thigh muscles. The DHA enrichment was independent of dietary EPA or 25(OH)D3, but that of 25(OH)D3 in the liver was decreased (68%, P < 0.05) by dietary DHA in Expt. 1. Compared with BD, BD + 25(OH)D3 enhanced (P < 0.05) gene expression related to D3 absorption (scavenger receptor class B type 1 and Niemann-pick c1 like 1) in the liver and D3 degradation (cytochrome P450 24A1) in the breast, and decreased mRNA or protein concentrations of vitamin D binding protein in the adipose tissue or thigh muscle. Supranutrition of DHA decreased mRNA concentrations of lipid metabolism-related genes (fatty acid desaturase 1,2, ELOVL fatty acid elongase 5, fatty acid desaturase 2, fatty acid synthase, and sterol regulatory element-binding protein 1).

CONCLUSIONS

Both DHA and 25(OH)D3 were enriched in the muscles up to meeting 50%-100% of the suggested intakes of these nutrients by consuming 2 servings of 100 g of fortified chicken. The enrichments altered gene expression related to lipid biosynthesis and vitamin D transport or storage.

Effect of Dietary Incorporation of Hemp Seeds Alone or with Dried Fruit Pomace on Laying Hens' Performance and on Lipid Composition and Oxidation Status of Egg Yolks

The present study was conducted to investigate the effects of introducing hemp seeds, as a source of PUFAs, into a standard diet with or without dried fruit pomace (dried blackcurrant (DB) or dried rosehip (DR)), as a source of natural antioxidants, on the laying performance of hens and the FA profile, cholesterol level, antioxidant content, and lipid oxidative status in the yolks of fresh eggs or eggs stored at 4 °C for 28 days. The experiment used 128 Tetra SL hens at 35 weeks of age, which were divided into four groups and randomly assigned to four dietary treatments: a standard corn-wheat-soybean meal diet (C), standard diet containing 8% ground hemp seed (H), hemp seed diet containing 3% dried blackcurrant pomace (HB), and hemp seed diet containing 3% dried rosehip pomace (HR). The laying rate, feed conversion ratio (FCR), egg weight, and yolk weight were improved by the use of hemp seeds. The yolks of the H, HB, and HR eggs had a lower cholesterol (p ˂ 0.01) and SFA content, while the concentration of total and individual PUFAs (n-6 and n-3 FAs) was significantly higher (p ˂ 0.01) compared to C. In addition, the introduction of hemp seeds into the diets alone or with dried fruit pomace (DB or DR) led to increased (p ˂ 0.001) content of α-linolenic acid (ALA, 18:3n-3), eicosapentaenoic acid (EPA, 20:5n-3), and docosahexaenoic acid (DHA, 22:6n-3) and hypo-/hypercholesterolemic FA ratio and decreased arachidonic acid (AA, 20:4n-6) content, n-6/n-3 ratio, and thrombogenicity index (TI) compared to the control eggs. The introduction of dried fruit pomace (DB or DR) into the diets had no effect on the laying performance of the hens or the cholesterol content and FA profile of the egg yolks, compared to the diet supplemented only with hemp seeds. The dried fruit pomace improved the color, accumulation of antioxidants, and oxidative stability of fats in the yolks of the fresh eggs and eggs stored at 4 °C for 28 days. The DR was found to have the most desirable effects, producing the most intense color of egg yolks, the highest content of natural antioxidants, and the best oxidative stability of yolk lipids.

Recent advances in microalgal production, harvesting, prediction, optimization, and control strategies

The market value of microalgae has grown exponentially over the past two decades, due to their use in the pharmaceutical, nutraceutical, cosmetic, and aquatic/animal feed industries. In particular, high-value products such as omega-3 fatty acids, proteins, and pigments derived from microalgae have high demand. However, the supply of these high-value microalgal bioproducts is hampered by several critical factors, including low biomass and bioproduct yields, inefficiencies in monitoring microalgal growth, and costly harvesting methods. To overcome these constraints, strategies such as synthetic biology, bubble generation, photobioreactor designs, electro-/magnetic-/bioflocculation, and artificial intelligence integration in microalgal production are being explored. These strategies have significant promise in improving the production of microalgae, which will further boost market availability of algal-derived bioproducts. This review focuses on the recent advances in these technologies. Furthermore, this review aims to provide a critical analysis of the challenges in existing algae bioprocessing methods, and highlights future research directions.

Nutritional Value of Microalgae and Cyanobacteria Produced with Batch and Continuous Cultivation: Potential Use as Feed Material in Poultry Nutrition

Recently, the demand for new alternative feedstuffs that do not contain chemical residue and are not genetically modified has been increased for sustainability in poultry production. In this respect, the usage of algae as animal feed is very promising as an alternative feed ingredient that reduces pollutant gases from animal production facilities. The aim of the current study is to investigate the usage possibility of algae, through determining nutritional value and production cost, as a feed ingredient in poultry nutrition. Three microalgae species, including Scenedesmus sp., Ankistrodesmus sp., and Synechococcaceae, were produced with batch and continuous cultivation to determine the difference in the lipid, protein, carbohydrate, fatty acid, and amino acid profiles, as well as the color characteristics and production cost. The highest lipid content of 72.5% was observed in algae biomass produced from Synechococcaceae with batch cultivation, whereas the highest protein level was found in algae biomass produced by Synechococcaceae under continuous cultivation practice (25.6%). The highest content of PUFA was observed in Scenedesmus sp. harvested from both batch and continuous cultivation (35.6 and 36.2%), whereas the lowest content of PUFA was found in Synechococcaceae harvested with continuous cultivation (0.4%). Continuously cultivated of Scenedesmus sp. had higher carbohydrate content than batch-cultivated Scenedesmus sp. (57.2% vs. 50.1%). The algae biomass produced from Synechococcaceae was found to have a higher content of essential amino acids, except lysine and histidine, compared to Scenedesmus sp. and Ankistrodesmus sp. Cultivation practices also affected the amino acid level in each algae species. The continuous cultivation practice resulted in a higher level of essential amino acids, except glycine. Synechococcaceae had richer essential amino acid content except for proline and ornithine, whereas continuous cultivation caused an incremental increase in non-essential amino acids. The lightness value was found to be the lowest (13.9) in Scenedesmus sp. that was continuously cultivated. The current study indicated that Scenedesmus sp. could be offered for its high PUFA and lysine content, whereas Synechococcaceae could have potential due to its high content of methionine and threonine, among the investigated microalgae and Cyanobacteria.

Yolk Fatty Acid Profile and Amino Acid Composition in Eggs from Hens Supplemented with ß-Hydroxy-ß-Methylbutyrate

In recent years, a supplementation of livestock animals, including poultry, with β-Hydroxy-β-methylbutyrate (HMB) has gained attention for its effects on protein and fat metabolism. This study investigates the effects of HMB in the laying hen diet on egg quality, focusing on amino acid and fatty acid composition. Laying hens were supplemented with 0.02% HMB, with performance parameters and egg components analyzed. HMB supplementation led to increased albumen weight, influencing egg weight while also reducing feed intake per egg without affecting laying rate, yolk indices, fat, or cholesterol content. Notably, the study revealed significant changes in egg amino acid and fatty acid profiles due to HMB supplementation. Various amino acids, including glycine, serine, and isoleucine, were altered in the yolk, impacting nutritional value and potential health benefits. Regarding fatty acids, the study observed changes in both saturated as well as n-6 and n-3 fatty acids, affecting the overall lipid profile of egg yolks. However, the shifts in fatty acid composition could have implications for cardiovascular health due to altered ratios of n-6/n-3 fatty acids. Further research is required to comprehensively understand the implications of these findings for consumer-oriented egg quality and health benefits.

Calcitriol combined with fish oil in the diet of Chukar partridge can ameliorate laying performance by improving oviduct histomorphometry and functions

The effects of calcitriol (CT) and/or fish oil (FO) on performance, oviposition time, sex ratio and morphology of the reproductive system of laying Chukar partridges were studied. Female (n = 48) and male (n = 16) partridges were used in a completely randomised design using a 2 × 2 factorial arrangement and were randomly allocated to either of four experimental treatments with four cage replicates of three females and one male each. Female birds received no FO (CON - FO) or were orally administered with 0.2 mL (0.24 g)/500 g body weight FO (CON + FO) or 0.2 mL solution containing 10 µg CT (CT - FO), or their combination (CT + FO) for 42 successive days. The eggs were collected every two hours between 07:00 and 23:00 h. Administering FO along with CT had considerably increasing effect on the male-biased sex ratio. FO and CT administration interacted to increase serum calcium concentration. Experimental treatments increased the number of leucocytes and erythrocytes. Serum cholesterol was decreased in CON + FO partridges compared with those of the CT - FO and CON - FO birds. There was an interaction between FO and CT on the weight of eggs and hatchlings, number of medium white follicles, diameter and the number of small yellow follicles, the weight and diameter of the fifth follicles (F5), and thickness of secondary mucosal folds in both uterus and vagina. Administering CT alone or with FO increased the feed intake, egg production, oviductal weight, diameter and number of large yellow follicles, the weight and diameter of the second (F2) and first (F1) follicles compared with those of the CON - FO females. Further studies are required to elucidate the mechanisms by which such changes in the sex ratio skew, ovary and oviduct are mediated.

Effects of dietary fermented peony seed dreg on the laying performance, albumen quality, antioxidant capacity, and n-3 PUFA-enriching property of laying hens

Introduction

It is of great importance to seek agro-industrial byproducts that can serve as unconventional or alternative feedstuffs for poultry, especially those that are substitutive sources of n-3 polyunsaturated fatty acids (PUFAs), as this will contribute to alleviating feed shortage pressure and improving poultry performance and product quality. In this study, the effects of dietary fermented peony seed dreg (FPSD) on the production performance of hens and fatty acid composition of meat and egg yolk were evaluated.

Methods

A total of 480 54-week-old Xinyang chickens were divided into 5 groups: control (basal diet); 5% peony seed dreg (PSD); and 5%, 7% and 9% FPSD, and each group consisted of 6 replicates with 16 birds per replicate. Production performances were recorded daily, and egg quality, serum parameters, antibody titers and fatty acid profile in the muscle and yolk were measured at 64 weeks of age.

Results and discussion

Egg production, feed conversion ratio and egg albumen quality were improved (p < 0.05) by 5% and 7% FPSD groups compared to 5% PSD and the control diet. Immune status was not influenced by PSD, but antibody titres against H7N9 and ND were improved by FPSD diets during most of the experimental periods. Dietary 5% and 7% FPSD increased (p < 0.05) serum high density lipoprotein concentrations and glutathione peroxidase actives. Total n-3 polyunsaturated fatty acids (PUFA) in meat and yolk increased gradually, while the total saturated fatty acids (SFA) and the n-6/n-3 PUFA ratio decreased gradually with increasing dietary FPSD levels. In conclusion, up to 7% dietary FPSD has the potential use to be utilized as a supplement in Xinyang laying hen diets to produce n-3 PUFA-enriched meat and eggs and positively affect production performance and health status.

Feeding Laying Ducks Eucommia ulmoides oliv. Leaves Increases the n-3 Fatty Acids Content and Decreases the n-6: n-3 PUFA Ratio in Egg Yolk without Affecting Laying Performance or Egg Quality

The objective was to determine the effects of supplementing duck diets with Eucommia ulmoides oliv. leaf powder (EUL). Laying ducks (n = 480) were randomly allocated into 4 experimental treatments and fed diets containing 0, 1, 2, or 4% EUL. Dietary inclusion of EUL had no effect (p > 0.05) on laying performance or egg quality, but linearly increased (p < 0.05) total plasma protein, globulin, and HDL-C concentrations with concurrent reductions (p < 0.05) in plasma concentrations of cholesterol and LDL-C. Eggs laid by ducks receiving EUL had yolks with linearly higher phenolic concentrations (p < 0.05) but lower cholesterol concentrations (p < 0.05). EUL supplementation in duck diets significantly reduced n-6: n-3 PUFA ratio by enriching n-3 fatty acids in yolks (p < 0.05) with no changes in n-6 PUFA (p >0.05).

Feeding laying hens docosa hexaenoic acid-rich microalgae oil at 40 g/kg diet causes hypotriglyceridemia, depresses egg production, and attenuates expression of key genes affecting hepatic triglyceride synthesis and secretion, but is rescued by dietary co-supplementation of high-oleic sunflower oil

The primary goal of this study was to investigate the effect of feeding White Leghorn hens graded levels of a docosahexaenoic acid (DHA)-rich microalgae oil (MAO) on productive performance and enrichment of eggs with very long-chain (VLC) omega-3 (n-3) polyunsaturated fatty acids (PUFA). Forty-nine-week-old hens (8 per diet) were fed the following diets for 28 d: 1) A corn-soybean meal-based diet with no supplemental oil (CON); 2) CON + 10 g/kg MAO; 3) CON + 20 g/kg MAO; 4) CON + 30 g/kg MAO; 5) CON + 40 g/kg MAO; 6) CON + 40 g/kg MAO + 20 g/kg high-oleic sunflower oil (HOSO); and 7) CON + 40 g/kg MAO + 40 g/kg HOSO. Diets 6 and 7 were included because we previously reported that co-feeding high-oleic acid oils with n-3 PUFA-containing oils attenuated egg yolk n-3 PUFA contents vs. feeding hens the n-3 oils alone. All data were collected on an individual hen basis. Egg VLC n-3 PUFA enrichment plateaued, in terms of statistical significance, at the 30 g/kg MAO level (266 mg/yolk). Hens fed 40 g/kg MAO had greatly attenuated measures of hen performance, marked liver enlargement, an altered ovarian follicle hierarchy, greatly lowered circulating triglyceride levels, and depressed hepatic expression of key genes involved in triglyceride synthesis and secretion. As compared to hens fed 40 g/kg MAO alone, feeding hens 40 g/kg MAO co-supplemented with HOSO (Diets 6 and 7) restored egg production, ovarian morphology, and all other measures of hen productive performance to CON levels, elevated plasma triglyceride levels, prevented liver enlargement, and increased the hepatic expression of key genes involved in triglyceride synthesis and secretion. In conclusion, MAO can greatly enrich hens' eggs with VLC n-3 PUFA, but its recommended dietary inclusion should not exceed 20 g/kg. This would allow for near-maximal yolk VLC n-3 PUFA enrichment without impairing hen productive performance, altering the ovarian follicle hierarchy or, based on the work of others, presumably imparting off-flavors in the egg.

Rhizopus oryzae fermentation wastewater nutrient removal coupling protein fodder production by employing Chlorella pyrenoidosa

The scenario was to investigate feasibilities of employing Chlorella pyrenoidosa for Rhizopus oryzae fermentation wastewater nutrient removal coupling protein fodder production. Results stated that TN, TP, NH₃-N, COD, BOD removal reached 99.79%, 94.70%, 98.80%, 97.60%, 99.60% to acquire discharge permit under fed-batch manipulation, whilst the peaked protein yield (19.94 g/L) was 6.04-fold more than batch manipulation. Rhizopus oryzae fermentation wastewater feeding C. pyrenoidosa was praised as high-quality protein not only with 26.78% essential amino acids and essential amino acids/nonessential amino acids value of 0.84 but also pathogenic bacteria and heavy metal loads complying with fodder standards. In vitro digestibility of dry matter, protein, lipid, and starch achieving 80.07%, 92.13%, 95.93%, 91.9% and bioavailability of polypeptides, triglycerides, free fatty acids, and oligosaccharides displaying 98.67%, 87.12%, 93.86%, 30.21%, which were roughly-equivalent to corn/soybean fodder. The findings formed exemplifications in utilizing other microalgal systems for wastewater nutrient removal coupling chemicals production.

Rosehip (Rosa canina L.) Meal as a Natural Antioxidant on Lipid and Protein Quality and Shelf-Life of Polyunsaturated Fatty Acids Enriched Eggs

Eggs are a common food of animal origin, inexpensive, and rich in bioactive substances with high biological value. Eggs enriched in polyunsaturated fatty acids (PUFA) are extremely desired by the progressive consumer. However, during storage, eggs undergo some physiochemical changes, which decrease their value. In this regard, the effect of dietary rosehip meal and flaxseed meal on hens’ egg quality characteristics, amino acids, fatty acids, health-related indices, antioxidant capacity, total polyphenols content, and shelf life was examined. For this study 120 Tetra SL laying hens, 29 weeks of age, were fed, for 4 weeks, three diets that included control (basal diet—RF0), basal diet + 1.5% rosehip and 7% flaxseed meal (RF1), and basal diet + 3% rosehip and 7% flaxseed meal (RF2). Productive performance of hens were recorded. The content of essential amino acids (EAA), antioxidant amino acids (AAA), and sulfur amino acids (SAA) was higher in RF1 and RF2, compared with RF0. Eggs belonging to the RF1 and RF2 groups had significantly (p < 0.05) higher content of n-3 PUFAs, especially linolenic and docosahexaenoic acids. Total antioxidant capacity and polyphenol content increased in both rosehip supplemented groups, but especially in RF2. Moreover, eggs from RF1 and RF2 groups maintained significantly higher egg quality parameters after storage for 14 and 28 days in the refrigerator (5 °C) and ambient temperature (21 °C), compared with those from the RF0 group. In the Haugh unit, yolk and albumen pH presented better values in RF1 and RF2 eggs compared to the RF0 eggs.

Microalgae-bacteria consortium for wastewater treatment and biomass production

The diversity of microalgae and bacteria allows them to form a complementary consortium for efficient wastewater treatment and nutrient recovery. This review highlights the potential of wastewater-derived microalgal biomass as a renewable feedstock for producing animal feed, biofertilisers, biofuel, and many valuable biochemicals. Data corroborated from this review shows that microalgae and bacteria can thrive in many environments. Microalgae are especially effective at utilising nutrients from the water as they grow. This review also consolidates the current understanding of microalgae characteristics and their interactions with bacteria in a consortium system. Recent studies on the performance of only microalgae and microalgae-bacteria wastewater treatment are compared and discussed to establish a research roadmap for practical implementation of the consortium systems for various wastewaters (domestic, industrial, agro-industrial, and landfill leachate wastewater). In comparison to the pure microalgae system, the consortium system has a higher removal efficiency of up to 15% and shorter treatment time. Additionally, this review addresses a variety of possibilities for biomass application after wastewater treatment.

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.

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.

Influence of dietary genistein and polyunsaturated fatty acids on lipid peroxidation and fatty acid composition of meat in quail exposed to heat stress

This experiment was conducted to investigate the effects of polyunsaturated fatty acids (PUFA) and genistein on performance and meat fatty acid profiles in quail exposed to heat stress. A total of 360 Japanese quail were divided into 12 groups in a 2 × 2 × 3 factorial design; each group comprised 30 quail with five replicates and were kept either at 22 ± 2 °C for 24 h/day (Thermoneutral, TN) or 34 ± 2 °C for 8 h/day (08:00 to 17:00 h) followed by 22 °C for 16 h (heat stress, HS) conditions. The diet contained either two levels of PUFA at 15 or 45% of total fat or three levels of genistein at 0, 400, or 800 mg/kg. Bodyweight gain, feed intake, and feed efficiency were lower (p ≥ 0.01) for quail reared under heat stress and fed low PUFA. Increasing dietary genistein in a linear manner improved the productive performance (p < 0.001). Heat stress caused increases in serum and thigh meat malondialdehyde (MDA) concentrations and decreases in genistein and vitamin E and A concentrations in serum and thigh meat (p < 0.001). High PUFA (PUFA45) in the diet of quail caused greater 18:2, 18:3 ALA, EPA, DHA, n-6, and n-3 PUFA as well as total PUFA and total USFA percentages (p < 0.001) in the thigh muscle, some of which decreased with heat stress (p ≥ 0.006) with no regard to genistein supplementation. This study revealed that genistein with greater doses along with greater PUFA inclusion to the diet of quail reared under heat stress is recommended for alleviating adverse effects of heat stress and for yielding healthier meat for human consumption.

Fatty acid profile of eggs produced by laying hens fed diets containing different shares of fish oil

This paper presents the results of the research on the use of fish oil (FO) in combination with soybean oil (SO) in laying hens diet on physical and chemical properties of fresh eggs and those stored in a refrigerator for 28 d at + 4°C. Fatty acids (FA) profile, as well as thiobarbituric acid reactive substances (TBARS) values in yolks are also presented. The following feeding treatments have been used: C (control, without FO), E1 (0.3% FO + 4.7% SO), E2 (0.6% FO + 4.4% SO), E3 (0.9% FO + 4.1% SO), E4 (1.2% FO + 3.8% SO) and E5 (1.5% FO + 3.5% SO). Laying hens diets were balanced at the level of 176.10 g/kg crude protein and 11.50 MJ/kg ME. The results of the study showed that feeding treatments affected the relative shares of the eggs basic parts (P < 0.05). The egg storage duration significantly reduced Haugh units (HU), egg and albumen egg weight, and increased the yolk color intensity (P < 0.001). Fish oil share increment in the diets resulted in the EPA (eicosapentaenoic FA) content increase from 10.27 to 20.10 mg/100 g egg; DHA (docosahexaenoic FA) from 105.44 to 236.87 mg/100 g egg and ∑ n-3 PUFA (polyunsatureated FA) from 204.59 to 327.35 mg/100 g egg. The ∑ n-6 PUFA/∑ n-3 PUFA ratio decreased from 8.69 (C group) to 4.54 (E5 group). TBARS values were affected by feeding treatments as well as treatment-storage interactions (P < 0.01).

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.

Cholesterol Content, Fatty Acid Profile and Health Lipid Indices in the Egg Yolk of Eggs from Hens at the End of the Laying Cycle, Following Alpha-Ketoglutarate Supplementation

The current study aimed to assess the effects of dietary alpha-ketoglutarate (AKG) supplementation to laying hens on the fatty acid (FA) profile and cholesterol levels of the egg yolk at the end of production cycle. The experiment was performed on forty-eight Bovans Brown laying hens randomly assigned to either a control group (CONT) or a group supplemented with AKG. The CONT group was fed the basal diet, and the AKG group was fed the basal diet plus 1.0% AKG from the 31st until the 60th week of age, when FA profile, fat and cholesterol content of the egg yolks were determined. No significant changes in the cholesterol and total fat content of the egg yolks were observed. However, there were positive (the decrease in n-6 FA and the increase in MUFA), and negative (decrease in PUFA and n-3 FA, increase in TI and n-6/n-3 ratio) changes in FA profile following AKG supplementation. In conclusion, it was shown that dietary AKG after a 30-week long supplementation influence FA profile in egg yolk and its nutritional value.

Profile of fatty acid lipid fractions of omega-3 fatty acid-enriched table eggs

The omega-3 fatty acid (FA) enrichment of yolk is a key means one of the main objectives to improve the nutraceutical properties of eggs. We evaluated the effect of the dietary inclusion of extruded linseed fed to laying hens on the fatty acid composition of the polar and non-polar lipid classes of the eggs. Two groups of 36 Lohmann White Leghorn layers (65 weeks old) were each fed one of two different diets for a period of 12 weeks. The two diets consisted of a conventional cereal-based diet concentrate (C) and a diet concentrate containing 5% linseed (L). The inclusion of linseed in the diet increased the content of α-linolenic (C18:3n-3), eicosapentaenoic (C20:5n-3) and docosahexaenoic (C22:6n-3) acids in neutral lipids, while a concomitant decrease in arachidonic acid (C20:4n-6) was observed. As regards the polar fraction, the fatty acid composition was slightly affected by the dietary treatments except for C18:0 (+1.14 fold), C18:2n-6 (+1.23 fold), C18:3n-3 (+2.8 fold) and C22:6n-3 (+1.41 fold). Principal component analysis demonstrated that very long-chain FAs were more representative of polar lipids, except for C20:5n-3, while neutral lipids were characterized by dietary n-3 FA (C18:3n-3).

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.

n-3 fatty acids fed to ISA brown and Shaver white breeders and their female progeny during rearing: Impact on egg production, eggshell, and select bone attributes from 18 to 42 weeks of age

The impact of feeding sources of n-3 fatty acids (FA) to ISA brown and Shaver white breeders and their female offspring during rearing on egg production, eggshell, tibia, and keel bone attributes was examined. Breeders were fed Control (CON) or CON + 1% dried microalgae (DMA: Aurantiochytrium limacinum) as the source of docosahexaenoic acid or CON + 2.6% of a coextruded mixture of full-fat flaxseed (FFF) and pulses as a source of α-linolenic acid. Day-old offspring were fed 1) breeder CON-pullet CON (CON-CON), 2) breeder CON-pullet DMA (CON-DMA), 3) breeder CON-pullet FFF (CON-FFF), 4) breeder DMA-pullet CON (DMA-CON), 5) breeder DMA-pullet DMA (DMA-DMA), 6) breeder FFF-pullet CON (FFF-CON), and 7) breeder FFF-pullet FFF (FFF-FFF). At 18 wk of age (WOA), pullets were fed a common layer diet to 42 WOA for egg production and bone quality assessments. There was no (P > 0.05) interaction between strains and diets and the main effect of diets on egg production, egg mass, and eggshell quality. There was an interaction (P = 0.008) between strain and diet on egg weight (EW); however, the strain effect on EW (P < 0.001) was such that ISA brown had heavier eggs than Shaver white. Shaver white had higher (P < 0.001) eggshell %, eggshell, and tibia breaking strength (BS), as well as tibia ash concentration compared with ISA brown hens. In contrast, ISA brown hens exhibited heavier (P < 0.05) tibia and keel bones. Feeding breeders DMA and pullets both sources of n-3 FA increased tibia medullary ash concentration compared with other diets (P < 0.001). Shaver white hens showed greater decline in tibia BS (83.7 vs. 96.3%) and ash content (84.1 vs. 94.3%) than ISA brown hens from 18 to 42 WOA (P < 0.05). Strain and diets exhibited independent effects on eggshell, tibia, and keel attributes. Provision of α-linolenic acid and docosahexaenoic acid to breeders and offspring improved tibia medullary ash concentration at 42 WOA.

Effects of dietary rubber seed oil on production performance, egg quality and yolk fatty acid composition of Hy-Line Brown layers

Objective

This study aims to evaluate the effects of dietary supplement of rubber seed oil on production performance, egg quality, and yolk fatty acid composition in laying hens during a 16-week feeding trial period.

Methods

Forty-eight 25-week-old laying hens of Hy-Line Brown were randomly divided into three groups. Each group comprised four replicates and each replicate had four birds. Rubber seed oil was incorporated into a corn-soybean meal basal diet by 3.5% (group I), 4.5% (group II), or 0 (control group) and equivalent nutrition was supplied for the test groups and the control group. The performance related values were determined using standard or well established methods.

Results

No significant difference was found in the production performance, the egg quality, the composition of saturated fatty acids, and the content of cholesterol and monounsaturated fatty acids in the yolk within the three groups. Interestingly, both test groups achieved a significantly higher content of linoleic acid, α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid and a significantly lower content of arachidonic acid (p<0.05) compared with the control group. With the increased level of dietary rubber seed oil, there was an increasing trend in the content of n-6 polyunsaturated fatty acids (PUFA), n-3 PUFA and total PUFA, but a declining trend in the n-6/n-3 ratio.

Conclusion

These results demonstrate that the rubber seed oil supplemented diet effectively improved the total PUFA content in eggs without impairing the layers’ production performance and the egg quality.

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.

Omega-3 and Omega-6 Fatty Acids in Poultry Nutrition: Effect on Production Performance and Health

Omega-3 (ω-3) and omega-6 (ω-6) fatty acids are important components of cell membranes. They are essential for health and normal physiological functioning of humans. Not all fatty acids can be produced endogenously owing to the absence of certain desaturases; however, they are required in a ratio that is not naturally achieved by the standard diet of industrialized nations. Poultry products have become the primary source of long-chain polyunsaturated fatty acids (LC-PUFA), with one of the most effective solutions being to increase the accretion of PUFAs in chicken products via the adjustment of fatty acids in poultry diets. Several studies have reported the favorable effects of ω-3 PUFA on bone strength, bone mineral content and density, and semen quality. However, other studies concluded negative effects of LC-PUFA on meat quality and palatability, and acceptability by consumers. The present review discussed the practical application of ω-3 and ω-6 fatty acids in poultry diets, and studied the critical effects of these fatty acids on productive performance, blood biochemistry, immunity, carcass traits, bone traits, egg and meat quality, and semen quality in poultry. Future studies are required to determine how poultry products can be produced with higher contents of PUFAs and favorable fatty acid composition, at low cost and without negative effects on palatability and quality.