Long-term effects of dietary supplementation with an essential oil mixture on the growth and laying performance of two layer strains

Essential Oil of Bay Laurel (Laurus nobilis) Enhances Growth and Immunity in Cold-Stressed Nile Tilapia (Oreochromis Niloticus)

Bay laurel (Laurus nobilis) essential oil is known for its antimicrobial, anti-inflammatory, and antioxidant properties. This study examined the effects of L. nobilis oil (LN) on Nile tilapia (Oreochromis niloticus) under cold stress conditions (16°C). Tilapia (initial weight, 5.02 ± 0.02 g) were acclimatized to 16°C for 14 days before being fed diets containing 0, 0.5, 1.0, 1.5, 2.0, and 2.5 g/kg LN oil for 84 days. The 1.5 g/kg LN oil group exhibited the highest final body weight and weight gain (p ≤ 0.05), while survival rates peaked at 1 g/kg. Biometric indices and feed efficiency were significantly enhanced, particularly at 1.5 g/kg (p ≤ 0.05). Histological analysis revealed improved intestinal and hepatic structures in LN-supplemented groups, although mild alterations were observed at 2.0 and 2.5 g/kg. Blood biochemical analysis showed increased total protein and reduced cholesterol in supplemented groups. Immune responses, including serum lysozyme activity and bacterial inhibition, were significantly enhanced at 1.5 g/kg or higher (p ≤ 0.05). Antioxidant enzyme activities, including superoxide dismutase (SOD) and catalase (CAT), increased (p ≤ 0.05) with LN oil supplementation, while malondialdehyde (MDA) levels decreased, indicating reduced oxidative stress. Gene expression analysis demonstrated increased insulin-like growth factor 1 and glucose transporter 4 levels with 1.5 g/kg LN oil, and tumor necrosis factor-alpha expression decreased at higher dosages. Dietary LN oil, particularly at 1.5 g/kg, enhances growth, immunity, and antioxidant defense in Nile tilapia under cold stress. Future studies should optimize dosages and explore broader applications across species and conditions.

The effect of thymus vulgaris extract and probiotic on growth performance, blood parameters, intestinal morphology, and litter quality of broiler chickens fed low-protein diets

This study investigated the effects of Thymus vulgaris extract (TVE) and probiotic (Protexin) on Arian broiler chickens fed low protein diets over 42 days. The 2 × 3 factorial experiment involved two dietary crude protein (CP) levels and three supplementations, each with five replicates of 10 birds. The CP levels included a control group and a low-CP group with 5% reduced CP content. The supplementations were: no additive, probiotic at 0.1 g/kg diet, and TVE at 1 ml/L drinking water. GC-MS analysis of TVE identified linalool (28.54%), carvacrol (20.22%), and thymol (7.07%) as key bioactive compounds. Low-CP diets increased feed intake (FI) and feed conversion ratio (FCR) during the grower period (P > 0.05). Additives boosted FI and body weight gain (BWG) during the starter period, with probiotics having a stronger effect (P < 0.05). TVE improved protein efficiency ratio (PER) and energy efficiency ratio (EER), while both TVE and probiotics enhanced European production efficiency factor (EPEF) to levels like normal-CP diets (P < 0.05). Intestinal morphology was unaffected by treatments (P > 0.05). Low-CP diets reduced serum albumin levels (P < 0.05). TVE lowered serum cholesterol and triglycerides, while probiotic reduced triglycerides (P < 0.05). TVE also decreased alkaline phosphatase (ALP), and probiotics reduced alanine transaminase (ALT) compared to control (P < 0.05). Cholesterol levels decreased with the normal diet combined with TVE, while TG levels were reduced with the diets combined with TVE and probiotics (P < 0.05). ALP and ALT levels dropped with low-CP × TVE and normal diet × probiotic, respectively (P < 0.05). Low-CP diets and TVE groups showed reduced litter nitrogen (P < 0.05). These results suggest that probiotics and TVE can alleviate the negative effects of low-CP diets on broiler performance. Additionally, probiotics and TVE improve blood biochemistry and litter quality in broiler chickens.

Essential oils mix effect on chicks ileal and caecal microbiota modulation: a metagenomics sequencing approach

Introduction

Microbiota plays a pivotal role in promoting the health and wellbeing of poultry. Essential oils (EOs) serve as an alternative solution for modulating poultry microbiota. This study aimed to investigate, using amplicon sequencing, the effect of a complex and well-defined combination of EOs feed supplement on both ileal and caecal broiler microbiota, within the context of Salmonella and Campylobacter intestinal colonization.

Material and methods

For this experiment, 150-day-old Ross chicks were randomly allocated to two groups: T+ (feed supplementation with EO mix 500 g/t) and T- (non-supplemented). At day 7, 30 birds from each group were orally inoculated with 106 CFU/bird of a Salmonella enteritidis and transferred to the second room, forming the following groups: TS+ (30 challenged birds receiving infeed EO mix at 500g/t) and TS- (30 challenged birds receiving a non-supplemented control feed). At day 14, the remaining birds in the first room were orally inoculated with 103 CFU/bird of two strains of Campylobacter jejuni, resulting in the formation of groups T+C+ and T-C+. Birds were sacrificed at day 7, D10, D14, D17, and D21. Ileal and caecal microbiota samples were analyzed using Illumina MiSeq sequencing. At D7 and D14, ileal alpha diversity was higher for treated birds (p <0.05).

Results and discussion

No significant differences between groups were observed in caecal alpha diversity (p>0.05). The ileal beta diversity exhibited differences between groups at D7 (p < 0.008), D10 (p = 0.029), D14 (p = 0.001) and D17 (p = 0.018), but not at D21 (p = 0.54). For all time points, the analysis indicated that 6 biomarkers were negatively impacted, while 10 biomarkers were positively impacted. Sellimonas and Weissella returned the lowest (negative) and highest (positive) coefficient, respectively. At each time point, treatments influenced caecal microbiota beta diversity (p < 0.001); 31 genera were associated with T+: 10 Ruminoccocaceae genera were alternatively more abundant and less abundant from D7, 7 Lachnospiraceae genera were alternatively more and less abundant from D10, 6 Oscillospiraceae genera were variable depending on the date and 4 Enterobacteriaceae differed from D7. During all the experiment, Campylobacter decreased in treated birds (p < 0.05). This study showed that EO mix modulates ileal and caecal microbiota composition both before and during challenge conditions, increasing alpha diversity, especially in ileum during the early stages of chick life.

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.

Dietary Effects of Some Plant Extracts on Laying Performance, Egg Quality, and Some Blood Parameters in Laying Hens at Different Cage Densities

This study was carried out to determine the effects of cage density and anise extract (AE), thyme extract (TE), and black cumin extract (BCE) supplementation in the diet of laying hens on laying performance, egg quality, and some blood parameters. A total of 288 Lohman White commercial hens were blocked according to the location of their cages. The four dietary treatments included a control, basal diet + 250 mg/kg of AE, basal diet + 250 mg/kg of BCE, and basal diet + 250 mg/kg of TE for 12 weeks. The cage density affected egg production (p < 0.05), feed consumption (p < 0.01), and cracked eggs (p < 0.05). Increasing the cage density caused a linear decrease in egg production and feed consumption. Compared to the control, there was a decrease in feed consumption (p < 0.01) in the plant extract groups, and in parallel, egg production decreased. An increased cage density did not affect the egg quality traits except the shell strength. The shell strength, yolk color, yolk index, albumen index, and Haught unit were significantly affected by the plant extracts. The cage density and plant extracts had a significant effect on the serum corticosterone and glucose (p < 0.01). The highest values of corticosterone and glucose were recorded for dietary TE with a cage density of 4 birds/cm2. On the other hand, the lowest values of these parameters were recorded for AE addition with a cage density of 3 birds/cm2. As a result, an increased cage density was associated with stress and depression in the feed consumption and metabolic profiles. Supplemental AE, BCE, and TE improved the laying performance and metabolic profiles.

Alleviating effect of dietary supplementation of benzoic acid, Enterococcus faecium and essential oil complex on coccidia and Clostridium perfringens challenge in laying hens

The purpose of this experiment is to explore the effects of dietary supplementation of benzoic acid, Enterococcus faecium, and essential oil complex (BEC) on coccidia and Clostridium perfringens challenge in laying hens. A total of 80 Lohmann gray laying hens (35 wk old) were allocated to 4 treatments in a 2 × 2 factorial arrangement with the main effects of Clostridium perfringens type A (CP) and coccidia challenge (with or without challenge) and 2 BEC levels (0 and 1,000 mg/kg). The total experimental period was 6 wk. The results showed that: the challenge group significantly decreased the laying rate and average daily feed intake (ADFI) of laying hens (P_Challenge < 0.01). The BEC + challenge group significantly increased the laying rate and decreased the feed conversion ratio (FCR) of laying hens (P_BEC < 0.05). The challenge significantly decreased the thickness, strength, and relative weight of eggshell (P_Challenge < 0.05). The BCE + challenge group significantly increased the relative weight and strength of the eggshell (P_BEC < 0.05). The challenge significantly increased the crypt depth of the duodenum, jejunum and ileum, and decreased the villus-to-crypt ratio (V/C) (P_Challenge < 0.01). The BEC + challenge group decreased the crypt depth of the duodenum and jejunum, and increased the V/C of the duodenum (P_BEC < 0.01). The pathological scores of duodenum and jejunum of the challenge group were significantly higher than other groups (P_Challenge < 0.01), while the BEC + challenge group had lower pathological scores of jejunum (P_BEC < 0.01). The challenge significantly decreased the mRNA expression of Occludin, Mucin-2, Zonula occluden-1 (ZO-1) (P_challenge < 0.05); whereas the BEC group significantly increased the expression of Occludin, Mucin-2, and Claudin-1 mRNA (P_BEC < 0.05). The challenge significantly increased the level of interleukin 1β (IL-1β) in the jejunum (P_Challenge < 0.05). Taken together, adding BEC to the diet can improved production performance and egg quality of layers, by protecting intestinal health against Clostridium perfringens type A (CP) and coccidia challenge.

Essential Oil Delivery Route: Effect on Broiler Chicken's Growth Performance, Blood Biochemistry, Intestinal Morphology, Immune, and Antioxidant Status

Simple Summary

Much research is devoted to the search for potent alternatives to antibiotic growth promoters in the poultry industry. It is hypothesized that the efficacy of potential alternatives could be influenced by their type and the delivery strategy utilized. Consequently, this study evaluated the efficacy of a commercial essential oil blend across different delivery routes as a potent alternative to in-feed antibiotics in broiler chickens using selected biochemical, immune, and performance parameters. The results provide evidence that the successive delivery of essential oils via in ovo and in-water routes in broiler chickens offers the potential to improve broiler chicken biochemical and antioxidant status. However, the in ovo delivery of essential oil at 0.2 mL dosage (saline + essential oil, dilution ratio—2:1) suffers the limitations of reduced hatchability.

Abstract

This study evaluated the effect of an essential oil blend and its delivery routes on broiler chicken growth performance, blood biochemistry, intestinal morphology, and immune and antioxidant status. Eggs were incubated and allotted to 3 groups: non-injected group, in ovo saline group, and in ovo essential oil group. On day 18 of incubation, essential oil in saline or saline alone was injected into the amnion. At hatch, chicks were assigned to post-hatch treatment combinations (1) in ovo essential oil + in-water essential oil (in ovo + in-water EO); (2) in ovo essential oil (in ovo EO); (3) in ovo saline; (4) in-water essential oil; (5) in-feed antibiotics (Bacitracin methylene disalicylate) and (6) a negative control (NC; corn-wheat-soybean diet) in 8 replicate cages (6 birds/cage) and raised for 28 day. The in ovo EO group reduced (p < 0.05) chick length and hatchability, all groups recorded no difference in growth performance at 0–28 day. The in ovo + in-water EO treatment reduced (p < 0.05) blood creatine kinase and aspartate aminotransferase levels whilst increasing (p < 0.05) total antioxidant capacity in birds. The in ovo + in-water delivery of EO might represent a potential antibiotic reduction strategy for the poultry industry but more research is needed to address the concern of reduced hatchability.

Isoquinoline alkaloids induce partial protection of laying hens from the impact of Campylobacter hepaticus (spotty liver disease) challenge

Spotty liver disease (SLD) is a serious condition affecting extensively housed laying hens. The causative bacterium was described in 2015 and characterized in 2016 and named Campylobacter hepaticus. Antibiotics are the only tool currently available to combat SLD. However, antimicrobial resistance has already been detected, so finding therapeutic alternatives is imperative. Isoquinoline alkaloids (IQA), such as sanguinarine and chelerythrine, have been shown to have immunomodulatory effects. It has been hypothesized that IQA could ameliorate some of the deleterious effects of SLD. This study aimed to address that hypothesis in an experimental disease induction model. Birds were fed with diets containing 2 different doses of an IQA containing product, 100 mg of product/kg of feed (0.5 ppm of sanguinarine) and 200 mg of product/kg of feed (1.0 ppm of sanguinarine). Two additional groups remained untreated (a challenged positive control and an unchallenged negative control). After 4 wk of treatment, birds from all groups except the negative control group were exposed to C. hepaticus strain HV10. The IQA treated groups showed a reduction in the number of miliary lesions on the liver surface and reduced lesion scores compared with untreated hens. A significant reduction of egg mass was detected 6 d after exposure to C. hepaticus in the untreated group (P = 0.02). However, there was not a significant drop in egg-mass in the IQA groups, especially those fed with a high dose of IQA (P = 0.93). IQA supplementation did not produce significant changes in intestinal villus height and crypt depth but did result in a significant reduction in the proinflammatory cytokine, interleukin-8, in the blood (P < 0.01). Microbiota analysis showed that IQA treatment did not alter the alpha diversity of the cecal microbiota but did produce changes in the phylogenetic structure, with the higher dose of IQA increasing the Firmicutes/Bacteroidetes ratio.

Other minor changes in production indicators included an increase in feed consumption (P < 0.01) and an increase in body weight of the treated hens (P < 0.0001). The present study has demonstrated that IQA confers some protection of chickens from the impact of SLD.

Cocktail of chelated minerals and phytogenic feed additives in the poultry industry: A review

This review article delineates the role of chelated minerals and phytogenic feed additives (PFAs) cocktail supplementation in improving the overall health status and production performance of poultry birds and its economic effects in the poultry industry. Organically complexed minerals have many advantages over inorganic sources. It has improved absorption and efficacy, which meets the bird's requirements comfortably with a low-dose level. Hence, inorganic forms can be replaced with lower-dose levels of organic minerals without any adverse effects on production performances in broilers and layers. PFAs possess medicinal properties, such as antimicrobial, antioxidant, adaptogenic, and immunomodulatory, therefore, could be recommended as supplements. They are also growth promoters that enhance the overall health status and augment poultry birds' production performance. Furthermore, the tremendous potential of PFAs could be extracted with the recent advances in science and technology. With the advantages of organically complexed minerals and multiple beneficial applications, there is a resurgence to develop PFAs as a cocktail of organic minerals to improve the overall health status of poultry birds and augment their productivity, which, in turn, helps the poultry industry to grow decisively and economically.

Effects of Fennel Seed Powder Supplementation on Growth Performance, Carcass Characteristics, Meat Quality, and Economic Efficiency of Broilers under Thermoneutral and Chronic Heat Stress Conditions

Simple Summary

Nowadays, great attention has been given to phytogenic products as a growth enhancer due to their safety and eco-friendly influences on animal nutrition. Thus, this investigation looked at the use of fennel seed powder at 0, 1.6, and 3.2% as a dietary additive on the performance, carcass traits, meat quality, and efficiency of the production of broiler chickens raised under thermoneutral and chronic heat stress conditions. In essence, 3.2% fennel seed powder in the diet of broilers enhanced the growth rate under chronic heat stress and decreased breast meat redness and temperature, suggesting that 3.2% fennel seed could be used as an agent for enhancing the broiler’s tolerance during chronic heat stress (CHS) condition from 19 to 41 days of age.

Abstract

Nowadays, phytogenic products have received great attention as a growth promoter due to their safety and environmentally friendly effect as a replacement for classical growth promoters such as antibiotics in animal nutrition. Thus, this research seeks the possibility of using fennel seed powder (FSP) as a dietary additive from 19 to 41 days of age on productive performance, carcass traits, meat quality, and production efficiency of broiler chickens raised under thermoneutral and chronic heat stress conditions. Thus, 216 one-day-old Ross-308 broiler chicks were divided into two equal groups. The first group was placed in an independent temperature-controlled room at 23 ± 2 °C. The broiler chicks from the second group were placed in a heat-stressed room and exposed to chronic heat stress conditions (32 ± 2 °C) for seven hours per day from 8 a.m. to 3 p.m. The experimental design was 2 × 3 factorial including two environmental temperatures (thermoneutral vs chronic heat stress) and three experimental diets that contained 0, 1.6, and 3.2% FSP. The chickens were randomly assigned to 18-floor pens per room temperature, representing six replicates per treatment and six birds per replicate. The results showed that dietary fennel seed powder during days 19–41 of age enhanced the growth rate of broiler chickens and improved breast meat redness and reduced temperature under chronic heat stress. In conclusion, 3.2% of fennel seed powder could be used as an agent for enhancing the broiler’s tolerance during chronic heat stress condition from 19 to 41 days of age. Moreover, it is necessary to study in further detail the nitrite and nitrate contents in FSP and their impacts on muscle redness (a*) as well as muscle temperature.

Effect of selected feed additives on egg performance and eggshell quality in laying hens fed a diet with standard or decreased calcium content

The aim of the experiment with 240 ISA Brown hens fed the diets with standard or decreased Ca level was to evaluate the effect of selected feed additives on laying performance and eggshell quality. The hens were allocated to 10 treatments, each containing 12 cages (replicates) of 2 birds. A 2 × 5 experimental arrangement was used. From 26 to 70 wks of age, experimental diets containing 3.20 or 3.70% Ca were used. The diets were either not supplemented, or supplemented with sodium butyrate, probiotic bacteria, herb extracts blend or chitosan. The decreased dietary Ca reduced eggshell quality indices in older hens (43-69 wks) (P<0.05) without effect on performance indices. The addition of the probiotic, herb extracts, or chitosan increased the laying rate (P<0.05). In older hens, i.e. at 69 wk, chitosan increased eggshell thickness and breaking strength, while herb extracts increased eggshell thickness (P<0.05). There was no interaction between the experimental factors in performance and eggshell quality. The used feed additives had no influence on fatty acid profile of egg lipids, however diet supplementation with chitosan decreased cholesterol concentration in egg yolk lipids (P<0.05). It can be concluded that such feed additives as probiotic, herb extracts, or chitosan may positively affect performance and eggshell quality, irrespective of Ca dietary level.

The Effect of Dietary Essential Oil Mixture Supplementation on Performance, Egg Quality and Bone Characteristics in Laying Hens

The aim of this study was to investigate the effect of seven different levels (0, 25, 50, 100, 200, 400, and 600 mg/kg) of a phytogenic feed additive containing a mixture of essential oils from thyme, black cumin, fennel, anise and rosemary on performance, eggshell quality, bone biomechanical properties and bone mineralization in laying hens. This study consisted of a total of 112, 21-week-old Super Nick laying hens, which were randomly distributed into seven experimental groups. During the 12-week experimental period, each experimental group of four replicates of four birds each was fed with seven treatment diets. Egg weight and egg mass were positively linearly affected by essential oil mixture supplementation. Also, eggshell thickness was increased quadratically by essential oil mixture supplementation. The biomechanical properties and tibia mineral content were adversely affected by essential oil mixture supplementation at the level of 600 and 400 mg/ kg, respectively. These results demonstrated that dietary supplementation with a low or medium concentration of essential oils improved bone parameters, while at high levels were adversely affected in laying hens.

Comparison of the effects of basil (<i>Ocimum basilicum</i>) essential oil, avilamycin and protexin on broiler performance, blood biochemistry and carcass characteristics

Abstract. The effects of a probiotic (protexin), a medicinal plant (basil essential oil) and an antibiotic growth promoter (avilamycin) as broiler feed additives on performance, carcass characteristics and some blood parameters of broilers were studied. A total of 600 Arian broilers were divided into six treatments, with four replicates of 25 birds. Treatments were a plant essential oil in three levels (200, 400 and 600 ppm), the probiotic (150 ppm), the antibiotic (150 ppm) and a control group with no additives. Birds in different treatments received the same diets during the experimental period. Growth performance, blood biochemical parameters and carcass traits were measured. There were no effects of dietary treatment on body weight gain, feed intake and feed conversion ratio of the broilers. Internal organ weights and carcass characteristics were not influenced by treatments; however, 200 ppm basil essential oil supplementation decreased abdominal fat (P < 0.05). Biochemical parameters including serum low-density lipoprotein (LDL), high-density lipoprotein (HDL) and total cholesterol were not statistically influenced. However, addition of 400 ppm basil essential oil into diet increased serum triglyceride as compared to the control (P < 0.05). Results of this experiment demonstrated that the herbal natural feed additives such as basil may be used as alternatives to an antibiotic growth promoter without any adverse effects on broiler production.

Performance, egg quality, and immune response of laying hens fed diets supplemented with mannan-oligosaccharide or an essential oil mixture under moderate and hot environmental conditions

In total, 432 thirty-six-week-old laying hens were fed a basal diet supplemented with mannan-oligosaccharide (MOS) or an essential oil mixture (EOM) from 36 to 51 wk of age. Hens were divided into 3 equal groups replicated 6 times with 24 hens per replicate. No significant difference was observed among the dietary treatments in terms of performance indices. Different from the dietary manipulation, high environmental temperatures negatively influenced all of the laying performance traits except the feed conversion ratio in association with the diminished feed consumption. The MOS, and particularly the EOM, tended to alleviate the deleterious effect of heat stress on BW gain. Mortality was higher in MOS-fed hens than with other treatments. A supplementation diet with MOS or EOM provided increments in eggshell weight (P < 0.01). Relative albumen weight was significantly decreased (P < 0.05) in response to EOM or MOS supplementation; however, this was not the case in the yolk weight rate. The MOS decreased albumen height and Haugh unit (P < 0.05). High environmental temperatures hampered entire egg quality characteristics except for the eggshell breaking strength and egg yolk weight. These results indicated that heat stress adversely affected both productive performance and egg quality. As for the results of this study, neither MOS nor EOM was efficacious in improving efficiency of egg production and stimulating humoral immune response in laying hens reared under moderate and hot climatic conditions. However, the ameliorative effect exerted by MOS and EOM on eggshell characteristics is conclusive.