Effects of long-term intake of carotenoid-enriched eggs on healthy people: a randomized controlled study

Red palm oil, a natural repository abundant in tocotrienols, tocopherols and carotenoids, is frequently employed as a pigment and nutritional enhancer in food products. The principal aim of this study is to explore the disparities in vitamin A levels, fatty acid profiles and gut microbiota among healthy adults who consume carotenoid-enriched eggs compared to those who consume normal eggs. A total of 200 hens were randomly assigned to either the red palm oil group or the soybean oil group, with the objective of producing carotenoid-enriched eggs and normal eggs. Throughout a six-month, double-blinded, randomized controlled trial, participants were instructed to consume one carotenoid-enriched or normal egg daily at a fixed time. Fecal and blood samples were collected from the participants at the start and conclusion of the six-month intervention period for further analysis. Our findings indicated that there was no significant change in the vitamin A level for daily supplementation with one carotenoid-enriched egg, but there were significant changes in some indicators of fatty acid profiles and gut microbiota compared to the control group of the population. Nonetheless, the consumption of eggs, regardless of carotenoid-enriched eggs or normal eggs, positively influenced dietary habits by reducing the intake of saturated fatty acids and enhancing the intake of monounsaturated and polyunsaturated fatty acids of the population.

Influence of rosehip (Rosa canina L.) leaves as feed additive during first stage of laying hens on performances and egg quality characteristics

This study aimed to evaluate the effects of rosehip leaves (RL) supplementation on the production performances and egg quality of laying hens during the first stage of laying. For that, 90 Lohmann Brown Classic hens, aged 26 wk, were randomly assigned to 3 dietary treatments as follows: a control diet (RL0), an experimental diet containing 0.5% rosehip leaves (RL0.5), and an experimental diet containing 1% rosehip leaves (RL1). The laying hens were accommodated in an experimental hall with identical pens (3.96 m2), and controlled microclimate conditions. The dietary treatments were administered for a 6-wk experimental period (26-32 d of age). During this time, production performance of hens was recorded. To assess the impact of RL on egg weight and its components evolution, egg yolk and albumen color, and primary chemical composition of egg constituents were determined every 2 wk. The effect on egg yolk fatty acids profile was determined only at the end of the trial. The results showed that RL0.5 and RL1 dietary treatments significantly improved laying rate, feed conversion ratio and egg mass compared with RL0 group. A significant effect on egg weight and its components was observed only over time, showing that RL has no effect on these parameters. Significant changes in egg yolk coloration were observed over time, with significant increases in L*, a* and b* chromomeric parameters in both RL0.5 and RL1 compared to RL0. Significant alterations were obtained from the sum of egg yolk fatty acids. The RL1 egg yolk presented significantly higher n-3, and significantly lower n-6 fatty acids, compared with both RL0 and RL0.5. Further research is warranted to explore the long-term effects of rosehip leaf supplementation on laying hens performance and egg quality.

Tryptophan Promotes the Production of Xanthophyll Compounds in Yellow Abdominal Fat through HAAO

Abdominal fat, which in the past was often regarded as waste and discarded, has in recent years been used as a fat source to produce meat by-products. Yellow abdominal fat has higher economic value. Therefore, improving the color of abdominal fat plays an important role in improving the appearance of meat products. This study aimed to identify the contributors and the regulatory network involved in the formation of yellow and white color in abdominal fat. We found that four xanthophyll compounds were significantly different in yellow and white abdominal fat chicken, including zeaxanthin, lutein, canthaxanthin, and β-cryptoxanthin. There were 551 different and 8 common metabolites significantly correlated with these 4 xanthophyll compounds. Similarly, a total of 54 common genes were identified in 4 common related pathways (Complement and coagulation cascades, Metabolic pathways, PPAR signaling pathway, Carbon metabolism) of the 8 common metabolites. The high expression of HAAO in the yellow abdominal fat group leads to the degradation of tryptophan and its intermediate 5-hydroxyindole, and subsequently to the formation of the four xanthophyll compounds. This process is also regulated by tyrosine, kynurenine 3-monooxygenase (KMO), homogentisate 1, 2-dioxygenase (HGD), etc. Together, these findings show the effect of tryptophan on abdominal fat color, as well as a negative regulatory effect of HAAO and 5-hydroxyindole on the production of xanthophyll compounds involved in abdominal fat coloration.

Effects of herbal dregs supplementation of Salvia miltiorrhiza and Isatidis Radix residues improved production performance and gut microbiota abundance in late-phase laying hens

The present study was designed to evaluate the effect of a mixture of Chinese medicinal residues (CMRs) consisting of Salvia miltiorrhiza residues (SMR) and Isatidis Radix residues (IRR) on productive performance, egg quality, serum lipid and hormone levels, liver and blood antioxidant capacity, oviduct inflammation levels, and gut microbiota in the late-laying stage. A total of 288 fifty-four-week-old BaShang long-tailed hens were divided into four groups. The feed trial period was 8 weeks. The control group was fed the basic diet as a CCMR group, supplemented with 3, 4, and 6% for the experimental groups LCMR, MCMR, and HCMR. The egg production rate of the MCMR group was 8.1% higher than that of the CCMR group (p < 0.05). Serum triglyceride (TG) levels of hens of the CMR-supplemented group were significantly decreased than those of the CCMR group (p < 0.05). The group supplemented with different levels of CMR had significantly higher serum HDL-C levels compared with the control group (p < 0.05). Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were remarkably increased for the LCMR and MCMR groups and significantly decreased for the HCMR group compared to CCMR (p < 0.05). Serum and liver glutathione peroxidase (GSH-PX) activities were significantly increased, and malondialdehyde (MDA) levels were significantly decreased in the MCMR group compared to the CCMR group (p < 0.05). The expression levels of tubal inflammatory factor markers (IL-4, IL-1β, TNF-α) in the MCMR and HCMR groups were consistent with the pathological findings of the sections. As for cecal microbiota, supplementation with CMR affected the alpha diversity of the cecum microbiome at the genus level. The Shannon index was significantly higher in the MCMR group than in the CCMR and HCMR groups (p < 0.05). Supplementation with different levels of CMR mainly regulated the ratio of intestinal Firmicutes to Bacteroidetes and the abundance of phyla such as Proteobacteria. In addition, CMR supplementation at different levels in the diet enriched lipid-metabolizing bacteria, such as Bacteroides and Ruminococcus_gnavus_group. Furthermore, according to linear discriminant analysis (LDA) effect size (LEfSe) analysis, the MCMR group showed an increase in the number of short-chain fatty acid-producing bacteria Romboutsia and fiber-degrading specialized bacteria Monoglobus. Therefore, supplementation of appropriate amounts of CMR to the diet of laying hens enhanced reproductive hormone levels, hepatic antioxidant capacity, and lipid metabolism, alleviated the levels of oviductal inflammatory factors, and modulated the abundance structure of bacterial flora to improve the late-laying performance and egg quality. The results of the current study showed that CMR is a beneficial feed supplement for chickens when added in moderation.

Effects of dietary local hemp seed meal as soybean meal alternative on productive performance, egg quality and yolk fatty acid composition of laying hens

Supply problems and rising soybean meal prices have an impact on increasing feed costs. Hemp seed meal (HSM) with high protein content has the potential to be used as an alternative to soybean meal. This study evaluated the impact of dietary HSM of Narlı Sarayı variety as a substitute for soybean meal on productive performances, egg quality and yolk fatty acid composition. A total of 120 Lohmann Brown laying hens aged 50 weeks were allocated into 4 groups and 10 repetitions. Birds received treatment without HSM (control group), or soybean meal substituted with 4%, 8% and 12% HSM. Dietary 4% significantly increased (p < 0.05) egg production and decreased FCR compared with 8% and 12% HSM group but did not differ from the control group in an overall period of 6 weeks. The inclusion of the 12% HSM group significantly decreased (p < 0.05) egg production. Meanwhile, there was no influence of hemp seed meal (p > 0.05) on feed intake, egg weight, body weight change, egg shape index, albumen index, albumen weight, Haugh unit, yolk weight, yolk index and eggshell thickness. Dietary 8% and 12% HSM significantly increased (p < 0.05) eggshell weight and yolk colour compared with control and 4% HSM groups. There was a significant increase (p < 0.05) in omega-3 fatty acid concentration and a decrease in yolk omega-6 to omega-3 fatty acids ratio with an increase in dietary HSM. It was concluded that dietary up to 12% HSM of the Narlı Sarayı variety decreased egg production and increased FCR. Increasing dietary levels of HSM increased eggshell weight, yolk colour and omega-3 fatty acids content and decreased the omega-6 to omega-3 fatty acids ratio.

Deposition and enrichment of carotenoids in livestock products: An overview

A wide range of research has illustrated that carotenoids play a key role in human health through their versatile beneficial biological functions. Traditionally, the majority dietary sources of carotenoids for humans are obtained from vegetables and fruits, however, the contribution of animal-derived foods has attracted more interest in recent years. Livestock products such as eggs, meat, and milk have been considered as the appropriate and unique carriers for the deposition of carotenoids. In addition, with the enrichment of carotenoids, the nutritional quality of these animal-origin foods would be improved as well as the economic value. Here, we offer an overview covering aspects including the physicochemical properties of carotenoids, the situation of carotenoids fortified in livestock products, and the pathways that lead to the deposition of carotenoids in livestock products. The summary of these important nutrients in livestock products will provide references for animal husbandry and human health.

Effects of Breeds on the Content of Functional Nutrition in Eggs

The purpose of this study was to compare the differences in the content of functional nutrients in eggs, performance parameters, and egg quality parameters of different chicken breeds. In Trial 1, 150 41-week-old hens of each breed, including the Dwarf Layer, White Leghorn, Silky fowl, Beijing-you chicken, and Shouguang chicken, were randomly assigned to the control (CON) and 2.5% flaxseed oil (FSO) groups to compare the difference in n-3 polyunsaturated fatty acid (PUFA) content in eggs. The contents of α-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and total n-3 PUFA in eggs were increased (p < 0.05) in the FSO groups. The ALA (4.28%), DHA (2.03%), and total n-3 PUFA (6.46%) contents in eggs of Dwarf Layer were the highest among the five breeds (p < 0.05). To further verify if other functional nutrients also have such differences, 600 24-week-old White Leghorn and Dwarf Layer were allocated to four groups: CON, FSO, 0.02% selenium-enriched yeast (SEY), and 0.20% marigold flower extract (MFE), in Trial 2. The content of functional nutrients in eggs was significantly increased (p < 0.05) after feeding these additions. After feeding FSO, the eggs of the Dwarf Layer had a higher n-3 PUFA content than the White Leghorn (p < 0.05). However, no significant differences were found in selenium and lutein content in different breeds. Performance and egg quality were not negatively impacted by FSO, SEY, or MFE.

Does the addition of choline and/or betaine to diets reduce the methionine requirements of laying quails? Assessment of performance and egg antioxidant capacity

The purpose of the present study was to assess the performance, quality of eggs internally and externally, and antioxidant capacity of yolks in laying quails with the administration of choline and betaine to diets containing reduced methionine levels. A total of 150 Japanese laying quails (Coturnix coturnix japonica) at the 10-wk age were randomly assigned to 6 experimental groups, each consisting of 5 replicates and 5 birds for 10 wk. The treatment diets were designed by adding the following substances: 0.45% methionine (C), 0.30% methionine (LM), 0.30% methionine + 0.15% choline (LMC), 0.30% methionine + 0.20% betaine (LMB), 0.30% methionine + 0.075% choline + 0.10% betaine (LMCB1), 0.30% methionine + 0.15% choline + 0.20% betaine (LMCB2). The treatments did not affect performance, egg production, or egg internal quality (P > 0.05). No significant effect was determined on the damaged egg rate (P > 0.05), but the egg-breaking strength, eggshell thickness, and eggshell relative weight decreased in the LMCB2 group (P < 0.05). Regarding lipid peroxidation, treatments did not affect the yolk 2,2 diphenyl-1-picrylhydrazyl value (P > 0.05), although the lowest thiobarbituric acid reactive substances value was observed in the LMB compared to the control group (P < 0.05). It may be summarized that methionine can be decreased to levels of 0.30% for laying quail diets with no negative effect on performance, egg production, or egg internal quality, whereas the combination of methionine (0.30%) and betaine (0.2%) could improve antioxidant stability of eggs over the 10-wk experimental period. These findings provide useful information to the traditional recommendations on the requirements of laying quail. However, further studies are needed to test whether these effects persist throughout extended study periods.

The use of purple carrot powder in the diet of laying quails improved some egg quality characteristics, including antioxidant capacity

The goal of the current experiment was to investigate the effect of dietary concentrations of purple carrot powder (PCP) on performance, egg production, egg quality, and the antioxidant capacity of the yolk in laying quails. A total of one hundred and fifty 22-week-old Japanese laying quails were allotted to 5 dietary treatments each with 6 replicates of 5 quails. Quails were allocated to five dietary treatments (0, 0.1, 0.2, 0.3, and 0.4%) with PCP addition at an increasing level from 0 to 4000 mg/kg diet respectively, which were fed ad-libitum throughout the duration of the experiment. No differences were detected between dietary treatments for any of the performance parameters or egg production. Eggshell weight and eggshell thickness (P < 0.05) were linearly affected by PCP dietary, reaching maximum levels at 0.4% of PCP supplementation, while the percentage of damaged egg and egg-breaking strength remained similar for all experimental groups (P < 0.05). Quails receiving PCP diets showed a yellowness (b*) (P < 0.05) egg yolk color than those fed the control diet, without affecting the rest of the color parameters and egg internal quality. Increasing PCP levels in diets reduced linearly yolk TBARS (P < 0.01) and increased linearly DPPH (P < 0.01). The addition of PCP, a safe and readily available agricultural by-product, as a component of the diet of laying quail was effective without adversely affecting quail production. Moreover, the inclusion of PCP in the diet might benefit laying quails' eggs by improving some quality traits and enhancing the yolk's antioxidant capacity, which could improve their shelf-life and acceptability.

Pros and Cons of Dietary Vitamin A and Its Precursors in Poultry Health and Production: A Comprehensive Review

Vitamin A is a fat-soluble vitamin that cannot be synthesized in the body and must be obtained through diet. Despite being one of the earliest vitamins identified, a complete range of biological actions is still unknown. Carotenoids are a category of roughly 600 chemicals that are structurally related to vitamin A. Vitamin A can be present in the body in the form of retinol, retinal, and retinoic acid. Vitamins are required in minute amounts, yet they are critical for health, maintenance, and performing key biological functions in the body, such as growth, embryo development, epithelial cell differentiation, and immune function. Vitamin A deficiency induces a variety of problems, including lack of appetite, decreased development and immunity, and susceptibility to many diseases. Dietary preformed vitamin A, provitamin A, and several classes of carotenoids can be used to meet vitamin A requirements. The aim of this review is to compile the available scientific literature regarding the sources and important functions, such as growth, immunity, antioxidant, and other biological activities of vitamin A in poultry.

Reuse of vegetable wastes in animal feed: the influence of red beet powder supplementation on performance, egg quality, and antioxidant capacity of layer quails

The survey was carried out to establish the impact of red beet powder (RBP) on performance parameters and egg quality in laying quails. One twenty hundred (120) female laying quails aged 22 weeks were randomly assigned into five groups of 4 females each, and six replicates. Treatments diets were formed by adding 0, 0.2, 0.4, 0.6, and 0.8% RBP to the basal diet. The dietary inclusion of RBP did not affect performance parameters and egg production (P > 0.05) except feed conversion ratio, which was quadratically affected (P < 0.05). The feed conversion ratio was improved in the 0.4% group with concerning control. The inclusion of RBP did not modify the yolk color (L*, a*, b*) or egg quality (P > 0.05). However, the yolk index showed the highest value (P < 0.05) in quails fed 0.2% RBP. Free radical scavenging capacity (DPPH) of the yolk decreased (P < 0.05) when RBP levels increased above 0.6%. In contrast, the 0.6% RBP group had the highest level of thiobarbituric acid reactive substances (TBARS). Data from the present study provide valuable information to include RBP as an ingredient without affecting performance and egg production. It is an interesting option within the framework of the circular economy and of reusing vegetable products to use this ingredient in animal feed.

Performance, Egg Quality, and Yolk Antioxidant Capacity of the Laying Quail in Response to Dietary Choline Levels

The current study determined the ideal dose of choline in the diet of laying quails based on egg development, egg quality, and antioxidant capacity. A total of 120 female quails (244.7 ± 10.38 g) were randomly assigned to 6 experimental groups with 5 replicates of 4 quails each. In the 10-week trial, treatment diets were formed by adding 6 choline chloride−60% concentrations providing 1500 (control), 2000, 2500, 3000, 3500, and 4000 mg/kg of choline. The feed intake of quails was quadratically affected (p < 0.05) by the choline level of the diet, in other developmental parameters, and by egg quality among these treatments. The feed intake was reduced to 2500 and 3000 mg/kg levels of choline in the diet compared to the control group. Free radical scavenging capacity (DPPH) of the yolk increased linearly (p < 0.001) with dietary choline levels. In contrast, the thiobarbituric acid reactive substances (TBARS) value decreased as dietary choline levels increased, except for 4000 mg/kg levels. Based on the findings of the current study, 1500 mg/kg of dietary choline is adequate to maintain performance parameters and egg quality in laying quails. However, to increase egg antioxidant capacity, in terms of the DPPH value, the dietary choline dose needs to be increased to 3500 mg/kg.

Stevia (Stevia rebaudiana) Improves Carotenoid Content in Eggs When Fed to Laying Hens

Stevia rebaudiana Bertoni is a shrub with leaves that have a high concentration of carotenoids such as lutein and zeaxanthin. Egg yolks are a bioavailable source of lutein and zeaxanthin. The consumption of these carotenoids has been linked with improved human health. To investigate the impact of dried stevia leaves at 0%, 1% and 2% on the quality variables, the chemical composition and antioxidant content of eggs, the experiment involved 90 Hy-Line Brown laying hens, housed in 30 enriched layer cages, in groups of three from 22 to 26 weeks of age. The impact on the internal qualities of stored eggs was also examined. Yolks from hens fed stevia had an enriched color compared with the controls. At the end of the experiment, the whole egg, without shell, of birds fed 2% stevia had a higher total carotenoid content (p < 0.001) compared with birds fed 1% and 0% stevia, i.e., 5.16 (µg/g), 4.23 (µg/g) and 2.96 (µg/g), respectively. Storage reduced albumen height and increased albumen pH (p < 0.001). Stevia supplementation did not interact (p > 0.05) with storage time among the egg quality variables. Consuming eggs from hens fed stevia may increase carotenoids in human diet.

Dietary Supplementation with Microencapsulated Lutein Improves Yolk Color and Lutein Content in Fresh and Cooked Eggs of Laying Hens

This study was conducted to compare the efficacy of diet supplemented with non-microencapsulated lutein (NL) and microencapsulated lutein (ML) in laying hens. A total of 270 Hy-line Brown laying hens (54 weeks old) were allocated to three groups with six replicates of 15 hens and were adapted to a wheat-soybean meal basal diet for two weeks. Next, the control birds were fed the basal diet, and the test birds were fed the basal diet supplemented with 600 mg/kg NL (12 mg/kg available lutein) or 90.1 mg/kg ML (10 mg/kg available lutein) for 35 days. Supplementation of lutein did not affect the productive performance of laying hens, but improved (P<0.05) the yolk color and red/green value (a*), with eggs from the ML group displaying improved color and a* values from the 15^th day of the experimental period. The blue/yellow value (b*) for the yolk showed an increase (P<0.05) through both NL and ML supplements. The yolk color of fried and boiled eggs and a* value of the yolk in fried eggs were improved (P<0.05) only through ML supplemented diet. Both NL and ML supplements resulted in lower (P<0.05) lightness and higher (P<0.05) a* values of yolk in boiled eggs, as well as higher (P<0.05) b* values in fried and boiled eggs. Yolk lutein content in fresh, fried, and boiled eggs was increased (P<0.05) in NL and ML groups with the latter being higher. In conclusion, ML improved yolk pigmentation and lutein retention in laying hens better than NL.

Consumer preferences and sensory characteristics of eggs from family farms

The objective of this study was to evaluate consumer habits as well as the sensory perception and characteristics of farm eggs produced in Los Ríos, Chile. Data were collected from an online survey of 197 respondents and a sensory evaluation carried out by 30 untrained panelists of 4 types of eggs (brown-shell and blue-shell eggs acquired from family farms, free-range eggs acquired from large, industrial systems, and white-shell cage eggs from industrial, cage systems.) To evaluate differences and preferences, data were analyzed in a GLM. In addition, sensory evaluation was analyzed using principal component analysis. In accordance with the survey, 99% of the participants eat eggs (P < 0.001), 58% eat 1 to 3 eggs/wk, and 84% declared to consume eggs at home (<0.0001). Surveyed participants reported that price and size are the determining factors (31%) when purchasing eggs. Among the physical characteristic for consumers, yolk color was the most important attribute rather than white color, egg appearance, texture, flavor, or odor. In the consumer acceptability test, farm eggs (either brown or blue shell) received the most favorable sensory evaluation by the panel and were preferred to both free-range and white-shell cage eggs. Yolk color was the most influential parameter in making this difference. Brown farm eggs were predominately selected for greatest general satisfaction by participants in both the sensory evaluation (P = 0.008) and in the survey (40%; P = 0.026). There were no differences between farm eggs (brown and blue shell, P > 0.05) in the evaluated parameters. There was a consequence in the information given from surveyed consumers and the sensory panel with the yolk color.

Health benefits of carotenoids and potential application in poultry industry: A review

Carotenoids are one of the widespread and ubiquitous lipid-soluble pigments that produce a wide range of colours which are universally found in various plants, microalgae, bacteria and fungi. Recently, interest in using carotenoids as feed ingredients has increased markedly owing to their bioactive and health-promoting properties. In terms of applications, carotenoid-rich products are widely available in the form of food and feed additive, supplements and natural colourants. Carotenoids play a versatile biological role that contributes to therapeutic effects, including anticancer, immunomodulators, anti-inflammatory, antibacterial, antidiabetic and neuroprotective. Dietary supplementation of carotenoids not only improves the production performance and health of poultry birds, but also enhances the quality of egg and meat. Several studies have suggested that the supplementation of plant derived carotenoids revealed numerous health-promoting activities in poultry birds. Carotenoids reduce the oxidative stress in pre-hatched and post-hatched birds through different mechanisms, including quench free radicals, activating antioxidant enzymes and inhibiting the signalling pathways. Use of carotenoids in poultry feed as a part of nutrient that confers bird health and improve product quality. Carotenoids play a critical role for the pigmentation of egg yolk, skin, legs, beak, comb, feather and fat. Birds consumed carotenoid deficient diet resulting hues of their egg yolk or pale coloured skin. Therefore, uniform pigmentation generally indicates the health status and quality of the poultry products. This review aims to gather recent information regarding bioactive properties of carotenoids and highlight pharmaceutical and health beneficial effects of carotenoids for the poultry industry. Additionally, it explores the importance of carotenoids as alternative feed ingredients for poultry to boost the production performance and replace synthetic medicine and nutrients.