Oregano essential oil in the diet of laying hens in winter reduces lipid peroxidation in yolks and increases shelf life in eggs

The impact of dietary oregano essential oil supplementation on fatty acid composition and lipid stability in eggs stored at room temperature

*1. In many countries, eggs are not refrigerated and must be stored at room temperature. The objective of this study was to explore the effects of dietary oregano oil (275 mg/ kg; ORE) versus an unsupplemented control diet (CON) on laying hens on the shelf life and fatty acid profile of eggs.2. Treatments were randomly distributed into 10 pens containing 27 birds each. A total of 200 eggs were collected from both groups on the same day and were stored for either 0, 10, 21 and 35 d. At each storage time, egg yolks were analysed for fatty acid profile and lipid peroxidation.3. The main indicator of lipid peroxidation, malondialdehyde (MDA), was significantly lower in ORE eggs compared to CON eggs (p = 0.001). Storage time had a significant impact on MDA concentrations (p = 0.023), with the highest found after 35 d. Significant differences were found for individual fatty acids, saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Palmitic acid, stearic acid, oleic acid, linoleic acid and arachidonic acid were significantly lower in ORE eggs compared to CON eggs (p < 0.05). Palmitoleic acid (p = 0.002), linolenic acid (p = 0.001) and docosahexaenoic acid (DHA, p = 0.001) were significantly higher in ORE eggs.4. Storage only affected oleic, linolenic, linoleic, arachidonic and docosahexaenoic acids (p < 0.05). Total SFA, MUFA, n-6 and ratio of n-3 to n-6 (n-3:n-6) PUFA were significantly higher in CON eggs (p < 0.05). The ratio of SFA to PUFA (SFA:PUFA, p = 0.005) and total n-3 PUFA (p = 0.001) were significantly higher in ORE eggs.5. The n-3:n-6 ratio was significantly impacted by treatment (p = 0.021) and storage (p = 0.031) with no significant interaction. This ratio is important for human health indication and could lead to the development of designer eggs.

Effects of a mixture of glycerol monolaurate and cinnamaldehyde supplementation on laying performance, egg quality, and antioxidant status in laying hens

BACKGROUND

This study aimed to determine the effects of a mixture of glycerol monolaurate and cinnamaldehyde (GCM) supplementation on the laying performance, egg quality, antioxidant capacity, and serum parameters of laying hens. A total of 1120 14-week-old Jingfen-1 strain laying hens with similar performance were randomly allocated to four dietary treatments: control, and GCM groups supplemented with 250, 500, or 1000 mg kg-1 for 12 weeks.

RESULTS

Compared with the control group, GCM-supplemented groups significantly reduced (P < 0.05) the rate of unqualified eggs of laying hens aged 17-24 weeks. Supplementation of GCM significantly increased (P < 0.05) yolk color and serum glutathione peroxidase (GSH-Px) activity but decreased (P < 0.05) the hydrogen peroxide (H2 O2 ) content in the serum of laying hens at the age of 20 weeks. Furthermore, groups supplemented with GCM showed a significant increase (P < 0.05) in Haugh unit, yolk color, activities of total superoxide dismutase and GSH-Px, and the glucose content in serum, and a decrease (P < 0.05) in the content of urea nitrogen and H2 O2 and malondialdehyde in serum of laying hens at the age of 24 weeks. 500 mg kg-1 GCM supplementation significantly increased (P < 0.05) the number of large white follicles and 1000 mg kg-1 GCM supplementation decreased the number of large yellow follicles in 28-week-old laying hens.

CONCLUSION

These results indicated that GCM supplementation has positive effects on reducing egg loss and improving egg quality in the early laying period of laying hens. © 2023 Society of Chemical Industry.

Effects of essential oils on egg production and feed efficiency as influenced by laying hen breed: A meta-analysis

Background and Aim

Successful rearing of laying hens to achieve optimal egg production is an endeavor that often faces various constraints and challenges, such as infectious diseases, environmental stressors, and fluctuations in feed quality. The incorporation of essential oils (EOs) into the diet of laying hens has attracted considerable attention in recent years. Therefore, our study aimed to evaluate the efficacy of EO inclusion in laying hen diets by considering the effects of production phase and breed on performance, egg quality, serum biochemistry, gut health, and antioxidant activity.

Materials and Methods

The articles were obtained from the Web of Science, Scopus, Science Direct, and PubMed using the search terms "essential oils," "laying hens," and "phytobiotics." Data from 27 articles and 71 experiments were grouped according to laying hen production phase and breed in the database. The EO levels ranged from 0 to 1000 mg/kg, with thymol and carvacrol being the major EOs. A mixed model was used to analyze the data. Random effects were applied to the treatment, and fixed effects were applied to EO level, production phase, and breed.

Results

Egg production, feed intake, feed efficiency, eggshell quality, villus height, crypt depth, superoxide dismutase, and glutathione peroxidase levels increased linearly (p = 0.05) and egg weight and mass increased quadratically (p < 0.05) with increasing EO concentrations. An interaction was observed between the EO level egg production and feed conversion ratio (p = 0.05). Serum glucose, cholesterol, and malondialdehyde levels decreased with increasing EO concentrations (p < 0.05).

Conclusions

The inclusion of EOs effectively increased egg production, feed efficiency, egg weight, egg mass, eggshell quality, oxidative enzymes, and intestinal health. In addition, the proportion of dietary EOs in lightweight laying hens was higher than that in semi-heavy-weight laying hens in improving egg production and feeding efficiency.

Effects of Enriched-in-Oleuropein Olive Leaf Extract Dietary Supplementation on Egg Quality and Antioxidant Parameters in Laying Hens

The objective of the present study was to evaluate the effects of an olive leaf extract obtained with an up-to-date laboratory method, when supplemented at different levels in laying hens' diets, on egg quality, egg yolk antioxidant parameters, fatty acid content, and liver pathology characteristics. Thus, 96 laying hens of the ISA-Brown breed were allocated to 48 experimental cages with two hens in each cage, resulting in 12 replicates per treatment. Treatments were: T1 (Control: basal diet); T2 (1% olive leaf extract); T3 (2.5% olive leaf extract); T4 (Positive control: 0.1% encapsulated oregano oil). Eggshell weight and thickness were improved in all treatments compared to the control, with T2 being significantly higher till the end of the experiment (p < 0.001). Egg yolk MDA content was lower for the T2 and T4 groups, while total phenol content and Haugh units were greater in the T2. The most improved fatty acid profile was the one of T3 yolks. The α-tocopherol yolk content was higher in all groups compared to T1. No effect was observed on cholesterol content at any treatment. Based on the findings, it can be inferred that the inclusion of olive leaf extract at a concentration of 1% in the diet leads to enhancements in specific egg quality attributes, accompanied by an augmentation of the antioxidant capacity.

Effect of dietary essential oil of oregano on performance parameters, gastrointestinal traits, blood lipid profile, and antioxidant capacity of laying hens during the pullet phase

Many benefits have been found in supplementing essential oils such as oregano oil (EOO) to poultry, including increased body weight gain, antioxidant activity, and better gastrointestinal morphology. However, few studies tested the influence of EOO supplementation on laying hens and reported conflicting results regarding its efficacy in improving their health and performance. Therefore, we aimed to explore the effects of dietary EOO on performance, gastrointestinal (GIT) traits, blood lipid, and antioxidant capacity in laying hens during the rearing phase. A total of 300-day-old Hy-line-Brown chicks were used, and treatment diets consisted of corn-soybean based either without (CON) or with EOO (Ecodiar®, 0.275 g/kg diet). Birds were randomized across treatments with five pens/treatment and 30-birds/pen. Pen weights and feed rejected were recorded every two weeks (1-17 weeks of age), to calculate daily feed intake (ADFI), body weight (BW), and daily weight gain (ADWG). At 11 and 14 weeks of age, blood samples were collected from 3 birds/pen and analyzed for blood lipids and antioxidant levels, and 5-birds/treatment were euthanized, and GIT traits were tested. Differences in measured parameters across weeks and between treatments were assessed using GLMM with Tukey’s Post hoc test applied to significant results in R 3.3.1 (α set at 0.05). Body weights at weeks 3, 11, 13, and 17 were significantly higher in the EOO group compared to the CON group (all P ≤ 0.05), ADWG was significantly higher in EOO birds compared to CON birds at 9 and 13 weeks old (all P ≤ 0.05), while no significant differences in ADFI were observed between treatments across weeks of the trials. At both 11 and 17 weeks old, triglyceride levels were significantly lower, while high-density-lipoprotein levels were higher in EOO (all P ≤ 0.05). Malondialdehyde levels were lower in the EOO group versus CON (p=0.01), while EOO birds had higher glutathione levels (p=0.01) than CON. Finally, at 12 weeks old, the weight of the entire GIT and empty gizzard were higher in the EOO group versus CON (all P ≤ 0.05), while liver and spleen weights were not significantly different between groups. In conclusion, dietary oregano supplementation exerted promoting effects on the performance of Hy-Line Brown pullets.

Dietary Oregano Essential Oil Supplementation Influences Production Performance and Gut Microbiota in Late-Phase Laying Hens Fed Wheat-Based Diets

This study aimed to investigate the potential effects of OEO on production performance, egg quality, fatty acid composition in yolk, and cecum microbiota of hens in the late phase of production. A total of 350 58-week-old Jing Tint Six laying hens were randomly divided into five groups: (1) fed a basal diet (control); (2) fed a basal diet + 5 mg/kg flavomycin (AGP); (3) fed a basal diet + 100 mg/kg oregano essential oil + 20 mg/kg cinnamaldehyde (EO1); (4) fed a basal diet + 200 mg/kg oregano essential oil + 20 mg/kg cinnamaldehyde (EO2); (5) fed a basal diet + 300 mg/kg oregano essential oil + 20 mg/kg cinnamaldehyde (EO3). Compared to the control group, group EO2 exhibited higher (p < 0.05) egg production during weeks 5−8 and 1−8. EO2 had a lower feed conversion ratio than the control group during weeks 1−8. The content of monounsaturated fatty acid (MUFA) in EO2 was higher (p < 0.05) than that of the control and AGP groups. EO2 increased (p < 0.05) the abundance of Actinobacteriota and decreased the abundance of Desulfovibri in the cecum. The abundances of Anaerofilum, Fournierella, Fusobacterium, and Sutterella were positively correlated with egg production, feed conversion ratio, and average daily feed intake, while the abundances of Bacteroides, Desulfovibrio, Lactobacillus, Methanobrevibacter, and Rikenellaceae_RC9_gut_group were negatively correlated with egg production, feed conversion ratio, and average daily feed intake. Dietary supplementation with 200 mg/kg OEO and 20 mg/kg cinnamaldehyde could improve egg-production performance, decrease feed conversion ratio, and alter the fatty acid and microbial composition of eggs from late-phase laying hens.

Natural Products of Plants and Animal Origin Improve Albumen Quality of Chicken Eggs

Albumen quality is recognized as one of the major yardsticks in measuring egg quality. The elasticity of thick albumen, a strong bond in the ovomucin-lysozyme complex, and excellent biological properties are indicators of high-quality albumen. The albumen quality prior to egg storage contribute to enhance egg’s shelf life and economic value. Evidence suggests that albumen quality can deteriorate due to changes in albumen structure, such as the degradation of β-ovomucin subunit and O-glyosidic bonds, the collapse of the ovomucin-lysozyme complex, and a decrease in albumen protein-protein interaction. Using organic minerals, natural plants and animal products with antioxidant and antimicrobial properties, high biological value, no residue effect and toxicity risk could improve albumen quality. These natural products (e.g., tea polyphenols, marigold extract, magnolol, essential oils, Upro (small peptide), yeast cell wall, Bacillus species, a purified amino acid from animal blood, and pumpkin seed meal) are bio-fortified into eggs, thus enhancing the biological and technological function of the albumen. Multiple strategies to meeting laying hens’ metabolic requirements and improvement in albumen quality are described in this review, including the use of amino acids, vitamins, minerals, essential oils, prebiotics, probiotics, organic trace elements, and phytogenic as feed additives. From this analysis, natural products can improve animal health and consequently albumen quality. Future research should focus on effects of these natural products in extending shelf life of the albumen during storage and at different storage conditions. Research in that direction may provide insight into albumen quality and its biological value in fresh and stored eggs.

Nutrient sources differ in the fertilised eggs of two divergent broiler lines selected for meat ultimate pH

The pHu+ and pHu− lines, which were selected based on the ultimate pH (pHu) of the breast muscle, represent a unique model to study the genetic and physiological controls of muscle energy store in relation with meat quality in chicken. Indeed, pHu+ and pHu− chicks show differences in protein and energy metabolism soon after hatching, associated with a different ability to use energy sources in the muscle. The present study aimed to assess the extent to which the nutritional environment of the embryo might contribute to the metabolic differences observed between the two lines at hatching. Just before incubation (E0), the egg yolk of pHu+ exhibited a higher lipid percentage compared to the pHu− line (32.9% vs. 27.7%). Although ¹H-NMR spectroscopy showed clear changes in egg yolk composition between E0 and E10, there was no line effect. In contrast, ¹H-NMR analysis performed on amniotic fluid at embryonic day 10 (E10) clearly discriminated the two lines. The amniotic fluid of pHu+ was richer in leucine, isoleucine, 2-oxoisocaproate, citrate and glucose, while choline and inosine were more abundant in the pHu− line. Our results highlight quantitative and qualitative differences in metabolites and nutrients potentially available to developing embryos, which could contribute to metabolic and developmental differences observed after hatching between the pHu+ and pHu− lines.

Potential Implications of Natural Antioxidants of Plant Origin on Oxidative Stability of Chicken Albumen during Storage: A Review

Enhanced albumen quality is reflected in increased thick albumen height, albumen weight, and Haugh unit value, while the antimicrobial, antioxidant, foaming, gelling, viscosity, and elasticity attributes are retained. Improved albumen quality is of benefit to consumers and to the food and health industries. Egg quality often declines during storage because eggs are highly perishable products and are most often not consumed immediately after oviposition. This review provides insights into albumen quality in terms of changes in albumen structure during storage, the influence of storage time and temperature, and the mitigation effects of natural dietary antioxidants of plant origin. During storage, albumen undergoes various physiochemical changes: loss of moisture and gaseous products through the shell pores and breakdown of carbonic acid, which induces albumen pH increases. High albumen pH acts as a catalyst for structural changes in albumen, including degradation of the β-ovomucin subunit and O-glycosidic bonds, collapse of the ovomucin-lysozyme complex, and decline in albumen protein–protein interactions. These culminate in declined albumen quality, characterized by the loss of albumen proteins, such as ovomucin, destabilized foaming and gelling capacity, decreased antimicrobial activity, albumen liquefaction, and reduced viscosity and elasticity. These changes and rates of albumen decline are more conspicuous at ambient temperature compared to low temperatures. Thus, albumen of poor quality due to the loss of functional and biological properties cannot be harnessed as a functional food, as an ingredient in food processing industries, and for its active compounds for drug creation in the health industry. The use of refrigerators, coatings, and thermal and non-thermal treatments to preserve albumen quality during storage are limited by huge financial costs, the skilled operations required, environmental pollution, and residue and toxicity effects. Nutritional interventions, including supplementation with natural antioxidants of plant origin in the diets of laying hens, have a promising potential as natural shelf-life extenders. Since they are safe, without residue effects, the bioactive compounds could be transferred to the egg. Natural antioxidants of plant origin have been found to increase albumen radical scavenging activity, increase the total antioxidant capacity of albumen, reduce the protein carbonyl and malondialdehyde (MDA) content of albumen, and prevent oxidative damage to the magnum, thereby eliminating the transfer of toxins to the egg. These products are targeted towards attenuating oxidative species and inhibiting or slowing down the rates of lipid and protein peroxidation, thereby enhancing egg quality and extending the shelf life of albumen.

Phytogenic Feed Additives in Poultry: Achievements, Prospective and Challenges

Simple Summary

Plant secondary metabolites and essential oils also known as phytogenics are biologically active compounds that have recently attracted increased interest as feed additives in poultry production, due to their ability to promote feed efficiency by enhancing the production of digestive secretions and nutrient absorption, reduce pathogenic load in the gut, exert antioxidant properties and decrease the microbial burden on the animal’s immune status. However, the mechanisms are far from being fully elucidated. Better understanding the interaction of phytogenics with gastrointestinal function and health as well as other feed ingredients/additives is crucial to design potentially cost-effective blends.

Abstract

Phytogenic feed additives have been largely tested in poultry production with the aim to identify their effects on the gastrointestinal function and health, and their implications on the birds’ systemic health and welfare, the production efficiency of flocks, food safety, and environmental impact. These feed additives originating from plants, and consisting of herbs, spices, fruit, and other plant parts, include many different bioactive ingredients. Reviewing published documents about the supplementation of phytogenic feed additives reveals contradictory results regarding their effectiveness in poultry production. This indicates that more effort is still needed to determine the appropriate inclusion levels and fully elucidate their mode of actions. In this frame, this review aimed to sum up the current trends in the use of phytogenic feed additives in poultry with a special focus on their interaction with gut ecosystem, gut function, in vivo oxidative status and immune system as well as other feed additives, especially organic acids.