Oregano essential oil (Origanum vulgare) to feed laying hens and its effects on animal health

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.

Plant essential oils improve growth performance by increasing antioxidative capacity, enhancing intestinal barrier function, and modulating gut microbiota in Muscovy ducks

Essential oils (EO) are known for their antioxidant, anti-inflammatory, antimicrobial, and growth-promoting properties. However, data rgarding their impact on the intestinal health and gut microbiota of ducks remain limited. Thus, this study aimed to investigate the effects of plant EO on the growth performance, intestinal health, and gut microbiota of Muscovy ducks. A total of 360 healthy male Muscovy ducks aged 1 d were randomly divided into 4 groups with 6 replicates and 15 ducks per replicate. Ducks were fed basal diets supplemented with 0, 100, 200, or 300 mg/kg EO. The results showed that 200 mg/kg EO supplementation significantly (P < 0.05) increased the final body weight and average daily gain, while significantly (P < 0.05) decreased the feed conversion ratio during the 56-d experimental period. Furthermore, dietary 200 mg/kg EO significantly (P < 0.05) enhanced antioxidant capacity and immune function and improved the barrier function of the intestine. Additionally, 16S rDNA sequencing analysis results showed that 200 mg/kg EO favorably modulated the cecal microbial diversities and composition evidenced by the increased (P < 0.05) the abundances of short-chain fatty acid-producing bacteria (e.g., Subdoligranulum and Shuttleworthia) and decreased (P < 0.05) abundances of potential enteric pathogenic bacteria (e.g., Alistipes, Eisenbergiella, and Olsenella). The relative abundance of beneficial bacteria was positively correlated with antioxidant, immune, and barrier function biomarkers. Overall, these findings revealed that dietary supplementation with 200 mg/kg EO had several potentially beneficial effects on the growth performance of Muscovy ducks by improving antioxidant capacity, enhancing the intestinal barrier function and favorably modulating gut microbiota.

Essential oils as valuable feed additive: A narrative review of the state of knowledge about their beneficial health applications and enhancement of production performances in poultry

New research has begun to develop safe and effective alternatives to feed-antibiotics as growth enhancers in response to mounting pressure on the poultry sector to do so. There is a significant demand for poultry products all across the world right now. To achieve this goal, key performance indicators are optimized, such as the rate of chicken growth, the amount of feed used, and the health of the flock as a whole. As a result of this growing need, various alternatives to antibiotics have entered the market. New approaches are desperately needed to keep poultry productivity and efficiency at a high level in the face of mounting pressure to limit the use of antibiotics. Recent years have seen an uptick in interest in the potential of aromatic plant extracts as growth and health boosters in poultry. The great majority of plants' positive effects are accounted for by essential oils (EOs) and other secondary metabolites. EOs have been proven to promote digestive secretion production, improve blood circulation, exert antioxidant qualities, reduce levels of dangerous microbes, and maybe improve the immune status of poultry. EOs are often believed to be safe, non-toxic alternatives because they are all-natural, chemical-free, and devoid of potentially harmful deposits. EOs are extracted from plants, and while there are thousands of them, only approximately 300 have been deemed to have significant commercial value. Many different types of bacteria, viruses, fungi, and parasites are negatively affected by EOs in multiple studies conducted both in vitro and in vivo. The review covers the fundamentals of EOs, their anti-oxidant and immunomodulatory capabilities, their growth-promoting benefits, and their effectiveness against numerous diseases in poultry.

Potential Applications of Essential Oils for Environmental Sanitization and Antimicrobial Treatment of Intensive Livestock Infections

The extensive use of antibiotics has contributed to the current antibiotic resistance crisis. Livestock infections of Salmonella spp, Clostridium spp. and E. coli antimicrobial-resistant bacteria represent a public threat to human and animal health. To reduce the incidence of these zoonoses, essential oils (EOs) could be effective antibiotic alternatives. This study aims at identifying EOs safe for use, effective both in complementary therapy and in the environmental sanitization of intensive farming. Natural products were chemo-characterized by gas chromatography. Three S. Typhimurium, three C. perfringens and four E. coli strains isolated from poultry and swine farms were used to assess the antimicrobial properties of nine EOs and a modified GR-OLI (mGR-OLI). The toxicity of the most effective ones (Cinnamomum zeylanicum, Cz; Origanum vulgare, Ov) was also evaluated on porcine spermatozoa and Galleria mellonella larvae. Cz, Ov and mGR-OLI showed the strongest antimicrobial activity; their volatile components were also able to significantly inhibit the growth of tested strains. In vitro, Ov toxicity was slightly lower than Cz, while it showed no toxicity on G. mellonella larvae. In conclusion, the study confirms the importance of evaluating natural products to consolidate the idea of safe EO applications in reducing and preventing intensive livestock infections.

Productive Performance, Ovarian Follicular Development, Lipid Peroxidation, Antioxidative Status, and Egg Quality in Laying Hens Fed Diets Supplemented with Salvia officinalis and Origanum majorana Powder Levels

This study aimed to assess the effect of dietary supplementation with different levels of Salvia officinalis and/or Origanum majorana on productive performance, ovarian follicular development, lipid peroxidation, antioxidative status, and egg quality in laying hens. Two hundred and ninety-four 45-week-old Bovans brown hens were allocated into seven groups, with seven replicates of six hens each. The first group was fed with the basal considered as a control (A); the second (B) and third (C) groups were provided with the same control diet further supplemented with 0.5 and 1 kg/ton Salvia officinalis, respectively; the fourth (D) and fifth (E) groups received the control diet further supplemented with 0.5 and 1 kg/ton Origanum majorana, respectively; while the sixth (F) and the seventh (G) groups were offered a diet supplemented with 0.5 kg/ton Salvia officinalis and 0.5 kg/ton Origanum majorana and 1 kg/ton Salvia officinalis and 1 kg/ton Origanum majorana, respectively. No significant effects were observed in the final body weight (BW) and feed intake (FI) of the laying hens. In the diets supplemented with Salvia officinalis and Origanum majorana, the egg weights for groups C, F, and G had significantly higher values only compared to group D. The supplementation of the diets with Salvia officinalis and/or Origanum majorana significantly (p < 0.05) increased the Follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol estrogenic hormone concentration, except for Origanum majorana at both levels with regard to estradiol. The dietary utilization of Salvia officinalis and Origanum majorana did not significantly alter the plasma glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT), total protein, albumin, globulin, and High density lipoprotein (HDL) parameters. Cholesterol, glucose, triglyceride, and Low density lipoprotein (LDL) were decreased (p < 0.05) in the birds fed with Salvia officinalis and/or Origanum majorana supplemented diets. Moreover, at both doses, the dietary supplementation with Salvia officinalis and Origanum majorana decreased (p < 0.05) the yolk cholesterol and liver Malondialdehyde (MDA) levels. In addition, the dietary enrichment with Salvia officinalis and/or Origanum majorana decreased (p < 0.05) the palmitoleic and stearic fatty acids' egg yolk concentration. In contrast, the yolk linoleic fatty acid concentration was significantly increased by Salvia officinalis and/or Origanum majorana. In conclusion, dietary supplementation with Salvia officinalis and/or Origanum positively affected productive performance, ovarian follicular development, antioxidant activity, hormonal status, and steroidogenesis in Bovans brown laying hens.

Growth performance, nutrient digestibility, blood parameters, and carcass characteristics by lambs fed an oregano and cobalt blend

Shifting ruminal fermentation via feeding a blend of oregano (Organum vulgare L.) essential oils and Co-lactate (EOC; Rum-A-Fresh, Ralco, Inc. Marshall, MN) could improve lamb growth and carcass performance. Eighteen Suffolk × Little Han Tail F1 male lambs (20.3 ± 0.23 kg BW and approximately 3 months old) were randomly assigned using a completely random design to one of three treatments. Treatments were (1) EOC0: basal ration without EOC, (2) EOC4: basal ration plus 4 g/d EOC, and (3) EOC7: basal ration plus 7 g/d EOC. Initial and 24 d BW was similar (P > 0.10), but at 48 and 72 d, lambs fed EOC7 demonstrated greater (P = 0.01) BW compared with EOC0 fed lambs, while lambs fed EOC4 were intermediate and similar (P > 0.05). Average daily gains (ADGs) for 0-24 and 0-72 d were greater (P < 0.05) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0, while DM intake was similar (P > 0.10). Feed conversions for 0-24 d were improved (P < 0.02) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0. However, 0-72-d feed conversions were greater (P < 0.01) for lambs fed EOC7 compared to lambs fed EOC0, with lambs fed EOC4 being intermediate and similar (P > 0.05). DM, NDF, and ADF digestibilities were similar (P > 0.10) among treatments, while CP digestibility was greater (P < 0.01) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0. Carcass weight and dressing percentages were improved (P < 0.01) for lambs fed EOC7 compared with lambs fed EOC0 and EOC4. Head width was greater (P > 0.01) for lambs fed EOC7 compared with lambs fed EOC0 and EOC4, while rump width was greater (P > 0.01) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0. Plasma triglyceride and cholesterol concentrations were lower (P < 0.05) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0, while albumin, total serum protein, and glucose concentrations were greater (P < 0.05) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0. Feeding an EOC blend as an alternative antibiotic growth promoter at 4 and 7 g/d linearly improved lamb growth performance, feed conversions, frame growth, carcass weights, dressing percentages, and immunity.

Effect of Origanum dubium, Origanum vulgare subsp. hirtum, and Lavandula angustifolia essential oils on lipid profiles and liver biomarkers in athletes

This study aims to determine the effects of essential oils of Origanum dubium (DUB), Origanum vulgare subsp. hirtum (HIR), and Lavandula angustifolia (LAV) on lipid profiles and liver biomarkers in athletes. Thirty-four trained athletes were randomly assigned to one of three experimental groups or the control group (CON). The concentrations of serum lipids and liver biomarkers were assessed before and after the 14-day essential oil intervention. Gas chromatography-mass spectrometry analysis showed 68.0 and 82.1% carvacrol in DUB and HIR, respectively, and 34.50% linalyl acetate and 33.68% linalool in LAV essential oils. One-way analysis of covariance (ANCOVA) indicated a significant difference (p = 0.001) among the groups for high-density lipoprotein cholesterol (HDL-C) when the associated preintervention values were used as a covariate. The related pairwise comparisons revealed that DUB (p = 0.001) and HIR (p = 0.024) had greater HDL-C values than CON. From the two-way ANOVA, an interaction between time (before vs. after) and the groups (DUB vs. HIR vs. LAV vs. CON) was found for HDL-C (p = 0.030). Findings indicated a significant increase in DUB (p = 0.0001) and HIR (p = 0.010) for HDL-C, and there was a significant decrease in DUB (p = 0.023) for low-density lipoprotein cholesterol. However, there was no difference in total cholesterol, triglycerides, and all liver biomarkers.

Changes in performance, egg quality and blood parameters of laying hens fed selenium and oregano oil

Context Organic and herbal additives in feed may lead to more healthy animal products. For this study, we hypothesised that an organic form of selenium and/or a herbal additive (oregano, Origanum vulgare L.) may improve performance of laying hens. Aims The study was designed to determine the effects of selenium source (SS, sodium selenite; or selenium yeast, SY), oregano essential oil (OEO) and a combination of Se and OEO on performance, egg quality and blood parameters of laying hens. Methods In total, 216 Lohmann LSL-Lite laying hens, 66 weeks of age, were assigned to feed on one of six diets: control group, receiving basal diet (BD); BD + 0.3 mg SS/kg; BD + 0.3 mg SY/kg; BD + 250 mg OEO/kg; BD + 250 mg OEO + 0.3 mg SS/kg; BD + 250 mg OEO + 0.3 mg SY/kg. For each treatment, there were six replicates of six hens each for 12 weeks. Key results Feed conversion ratio was higher (P &lt; 0.05) with the OEO diet than in the control. The SY diet decreased egg production and the OEO diet decreased egg mass (P &lt; 0.05), although this effect was reversed with the SY + OEO diet. This would illustrate a synergistic effect of OEO with SY. Highest and lowest yolk colour values were found with the SY and SS diets, respectively (P &lt; 0.05). Serum uric acid was lower with diets containing Se than the control diet (P &lt; 0.05). Glutathione peroxidase activity was highest with SY and SY + OEO diets and lowest with the OEO diet (P &lt; 0.05). Birds fed the SS + OEO diet showed the highest total antioxidant capacity and those fed SY showed the lowest total antioxidant capacity (P &lt; 0.05). Conclusions Based on the results of the current study, it can be concluded that SY diet have increasing effect on egg weight in laying hens. In addition, novel synergistic effects between OEO and SY diets on improving egg production, egg mass and feed conversion ratio have been found. In terms of oxidative status, the detected synergistic effects between OEO and SS diets on total antioxidant capacity and between OEO and SY diets on glutathione peroxidase (GPx) have not been reported before, that appreciate more clarifying investigations in future. Although, dietary supplemental SY individually and also with OEO increased GPx, adding SS to diet together with OEO showed more improving effect on GPx compared to the separate usage. Implications Dietary supplemental SY can improve egg weight in laying hens. In addition, adding SY to diet of laying hens individually and with OEO have beneficial effects on oxidative status of bird in terms of GPs activity, which in turn can ameliorate the unfavourable impressions of probable environmentally oxidative stress on productive performance.