Dietary Essential Oils Supplementation Research Articles

Effects of Dietary Essential Oils Supplementation on Egg Quality, Biochemical Parameters, and Gut Microbiota of Late-Laying Hens.

Simple SummaryImproving the laying cycle of laying hens and improving the quality of eggs has always been the goal pursued by the laying hen industry. As a potential green and healthy feed additive, plant essential oil has important research significance. The results of this experiment suggest that plant essential oils may improve the egg quality of Dawu Golden Phoenix laying hens by affecting cecal flora and serum biochemical indexes. As far as we know, there are few studies on the effects of plant essential oils on cecal flora, serum biochemical indicators and their relationship with egg-laying performance.The objective of this study was to explore the effects of adding essential oils (EO) to diets on egg quality, biochemical parameters and intestinal flora of late laying hens. The number of 252 Dawu Golden Phoenix laying hens (55 weeks old) were randomly sorted into two groups: the control group (CG) fed a basal diet and the EO group fed a basal diet with 300 mg/kg of essential oils. The average egg weight, feed-to-egg ratio, and egg production rate were determined every week. The trial started at week 55 and lasted for 8 weeks. During the experiment’s last week, 36 eggs out of each group were chosen at random to test. In our study, dietary supplementation with EO considerably decreased the egg breaking rate (p = 0.01) and increased the shell-breaking strength (p = 0.04). The treatment group’s alanine aminotransferase (ALT) levels were considerably lower than those of the control group (p = 0.03). The EO group had substantially higher total antioxidant capacity (T-AOC) and total superoxide dismutase (T-SOD) (p = 0.04 and p =0.03, respectively). However, there were no differences in alpha diversity indicators between the two groups. It is worth noting that Firmicutes were increased considerably (p < 0.05), while Spirochaetota and Proteobacteria were significantly reduced in the EO group. At genus levels, the EO supplementation increased the relative abundance of Intestinimonas (p < 0.05) and Megamonas (p < 0.01). In conclusion, a dietary supplementation of 300 mg/kg EO can improve the production performance of laying hens and the egg quality. It can also regulate the abundance of cecal flora and serum biochemical indicators.

Unveiling the effect of dietary essential oils supplementation in Sparus aurata gills and its efficiency against the infestation by Sparicotyle chrysophrii

A microencapsulated feed additive composed by garlic, carvacrol and thymol essential oils (EOs) was evaluated regarding its protective effect in gills parasitized by Sparicotyle chrysophrii in Sparus aurata. A nutritional trial (65 days) followed by a cohabitation challenge with parasitized fish (39 days) were performed. Transcriptomic analysis by microarrays of gills of fish fed the EOs diet showed an up-regulation of genes related to biogenesis, vesicular transport and exocytosis, leukocyte-mediated immunity, oxidation–reduction and overall metabolism processes. The functional network obtained indicates a tissue-specific pro-inflammatory immune response arbitrated by degranulating acidophilic granulocytes, sustained by antioxidant and anti-inflammatory responses. The histochemical study of gills also showed an increase of carboxylate glycoproteins containing sialic acid in mucous and epithelial cells of fish fed the EOs diet, suggesting a mucosal defence mechanism through the modulation of mucin secretions. The outcomes of the in vivo challenge supported the transcriptomic results obtained from the nutritional trial, where a significant reduction of 78% in the abundance of S. chrysophrii total parasitation and a decrease in the prevalence of most parasitic developmental stages evaluated were observed in fish fed the EOs diet. These results suggest that the microencapsulation of garlic, carvacrol and thymol EOs could be considered an effective natural dietary strategy with antiparasitic properties against the ectoparasite S. chrysophrii.

Consequences of various housing systems and dietary supplementation of thymol, carvacrol, and euganol on performance, egg quality, blood chemistry, and antioxidant parameters

The present work was carried out to investigate the influences of housing system and dietary essential oils (EOs) supplementation to laying hens on the productive performance, egg quality, immunity, antioxidant parameters, and hematology. A factorial arrangement (2 × 4) was performed, including 2 housing systems and 4 different types of EOs (without EOs, thymol, carvacrol, and euganol) during the production stages (from 28–78 wk of age). Birds were randomly divided into 2 groups with each of 2,000 birds. The first group was moved to laying cages while the second group was a floor reared. Each group was randomly divided into 4 groups (5 replicates of 100 birds each): The first were considered as a control group, and the second, third, and fourth groups were treated with thymol, carvacrol, and euganol EO, respectively. The results showed that hens reared in cage system had higher egg weight (P < 0.05), egg production, egg mass, and feed intake and better feed conversion ratio (P < 0.001) than those reared in the floor system. Blood picture values (except white blood cells), phagocytic index, phagocytic activity, and blood chemistry parameters (except calcium, phosphorus, and urea values) of laying hens were not affected (P > 0.05) by housing system. The groups fed EOs showed a rapid improvement (P < 0.001) in the egg production%, egg weight, egg mass, and egg quality. Thymol group had the highest egg production (P < 0.001). Thymol and eugenol groups had the highest egg weight, egg mass, and egg quality (P < 0.001). The groups fed diets containing thymol or eugenol consumed lower feed and had better feed conversion ratio (P < 0.001) than the control group. Immunity indices (phagocytic activity [P < 0.05], avian influenza [AIH5 and AIH9], P < 0.001) were improved with the presence of EOs in the laying hen diet. These results strongly suggest that dietary EO supplementation could be a successful attempt to improve the productive performance, egg quality, and immunity of laying hens.

GROWTH PERFORMANCE, FEED EFFICIENCY AND BLOOD PARAMETERS IN NILE TILAPIA EXPOSED TO MERCURY TOXICITY AND ITS REDUCTION BY USING DIETARY SUPPLEMENTATION OF ESSENTIAL OILS

A 112-day feeding trial was performed to investigate the toxic effects of mercury on Nile tilapia (Oreochromis niloticus) and attempt to detoxify these drastic effects by using dietary supplementation of citronella (Cymbopogon nardus) and geranium (Pelargonium graveolens) (GEO) essential oils. Fish were divided into four groups, each group was stocked into 3 aquaria, each one contains 10 fish. The first group was fed on basal diet without mercury, the second group was fed on basal diet containing 50 ppm mercury as mercuric chloride (HgCl2), each of third and fourth group was treated with 50 ppm HgCl2 and supplemented with 400 mg/kg diet citronella or geranium oils, respectively. Live body weight at 16 week was significantly increased by 40.76%, 22.64 and 12.41%, respectively in each of fish group fed diets without mercury (basal diet), fish group fed a diet contaminated with mercury and supplemented with citronella oil and fish group fed a diet contaminated with mercury and supplemented with geranium oil when compared with those fed diet contaminated with mercury. Also, daily weight gain at 0-16 weeks significantly increased by 51.38, 28.44 and 15.60%, respectively. Feed conversion at 0-16 weeks significantly improved by 29.56, 16.92 and 14.27%, in fish group fed diets without mercury (basal diet), fish group fed a diet contaminated with mercury and supplemented with citronella oil and fish group fed a diet contaminated with mercury and supplemented with geranium oil, respectively, when compared with those fed diet contaminated with mercury. Serum total protein and albumin significantly increased, while serum ALT, AST, urea-N and Createnine were decreased in fish groups fed diets without mercury. Also serum total protein increased in fish groups fed diet contaminated with mercury and treated with citronella or geranium oil than those fed diet contaminated with mercury. Residual of mercury significantly decreased (P<0.001) by 29.53 and 31.49 in liver and muscles of fish group fed a diet contaminated with mercury and supplemented with citronella oil, respectively. Also in fish group fed a diet contaminated with mercury and supplemented with geranium oil decreased by 41.45 and 47.24, respectively. Based on the obtained results it could be concluded that, growth rate and feed conversion improved by dietary essential oils supplementation.

Effect of Dietary Essential Oils Supplementation on Growth Performance, Nutrient Utilization, and Protein Digestibility of Juvenile Gilthead Seabream Fed a Low‐Fishmeal Diet

AbstractThe present study aimed to assess the efficacy of supplemental plant essential oils (PEOs) on the growth performance and digestive processes of juvenile gilthead seabream. Three experimental diets were tested: (1) a control (CTRL) diet formulated with low marine‐derived protein level (19%); (2) CTRL diet supplemented with a blend of anise, citrus, and oregano essential oils at 1.2 g/kg (diet Phyto C); and (3) CTRL diet supplemented with a similar blend at 0.2 g/kg, but in encapsulated form (diet Phyto E). Triplicate groups of 20 fish (mean initial body weight = 27.9 ± 2.1 g) were fed the experimental diets over 63 d. Results showed that specific growth rate, voluntary feed intake, feed conversion ratio, and protein efficiency ratio were not significantly affected by the two dietary supplements. The commercial blend of PEOs tested here can be successfully incorporated into a low‐fishmeal diet to maximize protein and fat retention and to minimize nitrogenous losses in seabream juveniles. Phyto E presented a decrease in nitrogenous metabolic and fecal losses. The practical implications of including this plant‐based blend in aquafeeds can potentially include faster fish growth and improved production time, but these remain to be tested in a longer experimental trial.

In vitro antibacterial activity of thymol and carvacrol and their effects on broiler chickens challenged with Clostridium perfringens.

BackgroundIn the post-antibiotic era, essential oils (EO) are promising alternatives to growth-promoting antibiotics. The aim of the present study was to investigate the antibacterial activities of an EO product and its components thymol and carvacrol in vitro, and the efficacy of EO to control Clostridium perfringens challenge in broiler chickens.ResultsThe in vitro minimum inhibitory concentration assay showed strong antibacterial activity of the EO product, thymol, and carvacrol against pathogenic Escherichia coli, C. perfringens, and Salmonella strains, and weak activity towards beneficial Lactobacillus strains. Besides, an additive effect was observed between thymol and carvacrol. The in vivo study was carried out with 448 male broiler chicks following a 4 × 2 factorial arrangement to test the effects of EO supplementation (0, 60, 120, or 240 mg/kg EO in wheat-based diet), pathogen challenge (with or without oral gavage of C. perfringens from day 14 to day 20) and their interactions. Each treatment consisted of eight replicate pens (seven birds/pen). The challenge led to macroscopic gut lesions, and resulted in a significant increase in ileal populations of C. perfringens and Escherichia subgroup (P ≤ 0.05) on day 21. Dietary EO supplementation did not influence C. perfringens numbers, but linearly alleviated intestinal lesions on day 21 and 28 (P = 0.010 and 0.036, respectively), and decreased Escherichia populations in ileum with increased EO dosages (P = 0.027 and 0.071 for day 21 and 28, respectively). For caecum, EO quadratically influenced Lactobacillus populations on day 21 (P = 0.002), and linearly decreased the numbers of total bacteria and Escherichia on day 28 (P = 0.026 and 0.060, respectively). Mean thymol and carvacrol concentrations in the small intestine were 0.21 and 0.20 μg/g in intestinal digesta (wet weight), respectively, for birds fed 60 mg/kg EO, and 0.80 and 0.71 μg/g, respectively, for birds fed 240 mg/kg EO.ConclusionsThese results indicated that dietary EO supplementation could affect intestinal microbiota and alleviate intestinal lesions in broilers, which may contribute in controlling C. perfringens infection in broiler chickens.

Effect of increasing doses of a microencapsulated blend of essential oils on performance of lactating primiparous dairy cows

This study determined impacts of a commercial blend of microencapsulated essential oils (EO), fed at increasing dose levels to high yielding primiparous dairy cows, on milk yield and composition. Eight pregnant Holstein heifers, selected to have their parturition within a period of 30 d, were kept in tie stalls equipped for individual feeding, and with free access to water, from the 7th month of gestation. At an average of 40 d postpartum, cows were assigned to one of four dietary EO levels in a replicated 4 × 4 Latin square design. The experimental diets (i.e., corn silage, fescue hay and a compound feed, 6.5, 4.4 and 8.7 kg DM/d respectively) differed only in the addition level of a microencapsulated EO supplement (RumaXol Feed) mixed at different levels into the compound feed (fed at 1 kg/cow day) in order to provide 0, 0.32, 0.64 and 0.96 g/d of the EO mixture. The experiment had four experimental periods of 21 d, with the last 5 d used for collection of faeces and urine, for milk yield and composition recording and measurement of cow biometric data. The dietary EO supplementation had no effect on dry matter (DM) intake, water consumptions or faecal DM, while urine density was ( P=0.01) lower at the intermediate EO dosages. Digestibility and biometric measures of cows were not modified by EO feeding. The protein content of milk tended ( P=0.06) to be higher at the intermediate EO dosages, as did ( P=0.05) the milk energy concentration. However milk and milk component yields were not affected by EO feeding level.