Effects of Curcuma longa rhizome powder on egg quality, performance and some physiological indices of laying hens fed different levels of metabolizable energy

Meta-Analysis of Positive Effects of Dietary Turmeric (Curcuma longa L.) on Performance of Commercial Laying Hens

Turmeric improves performance in nonruminants, but results in laying hens are not consistent. This meta-analysis assessed the performance of laying hens fed turmeric powder (TP)-based diets. Nineteen studies retrieved from Google Scholar, Scopus, ScienceDirect, PubMed, and Web of Science databases were used for the meta-analysis. The outcome variables analysed were productive indices (feed intake [FI], feed conversion ratio [FCR], hen day production [HDP], egg weight [EW], egg mass [EM]), egg quality (Haugh unit [HU], shell thickness [SHT], shell strength [SHS], yolk cholesterol [YC]), serum biochemical parameters (serum cholesterol [SC], alanine transferase [ALT], and aspartate transferase [AST]), and moderator variables (layer strains, inclusion level, feeding duration, and hen's age). All analyses were performed on OpenMEE software and the R package. A random-effects model (REM) was used and results were presented as standardised mean difference (SMD) at a 95% confidence interval (CI). The results showed that dietary TP improved FCR (SMD = -0.31; 95% CI: -0.61, -0.01; p = 0.046) and HDP (SMD = 0.49; 95% CI: 0.29, 0.69; p < 0.001), but not EW, EM, HU, SHT, SHS, YC, and serum AST in layers. On the other hand, dietary TP decreased FI (SMD = -0.15; 95% CI: -0.26, -0.05; p = 0.004), SC (SMD = -75.18; 95% CI: -102.55, -47.80; p < 0.001), and ALT (SMD = -3.55; 95% CI: -4.71, -2.40; p < 0.001) in laying hens with proof of significant heterogeneity. However, meta-regression showed that layer strains and feeding duration accounted for most of the sources of heterogeneity. In conclusion, results suggest that dietary TP increased HDP and reduced FI, FCR, SC, and ALT in laying hens.

The Beneficial Application of Turmeric (Curcuma longa L.) on Health and Egg Production, in Layers: A Review

BACKGROUND

Turmeric (Curcuma longa L.) is a widely recognized spice and medicinal plant that has gained significant attention for its potential health benefits. This review aims to provide a comprehensive overview of the beneficial applications of turmeric in improving health and egg production in layers.

OBJECTIVE

The objective of this review is to assess the current scientific literature on the effects of turmeric supplementation in layer diets and evaluate its impact on layer health and egg production.

METHODS

A systematic search was conducted in Google Scholar database to identify relevant studies published in peer-reviewed journals. Studies investigating the effects of turmeric or its bioactive compound curcumin on layer health and egg production were included. Data on various parameters, including immune function, reproductive performance, egg quality and production parameters, were extracted and analysed.

RESULTS

Turmeric contains a bioactive compound called curcumin, which possesses antioxidant, anti-inflammatory, antimicrobial and immunomodulatory effects. These properties have been extensively studied and have shown promising results in enhancing layer health and performance. Turmeric supplementation has been reported to improve the overall immune response in layers, reducing the incidence and severity of infectious diseases. It has also been shown to have positive effects on gut health by modulating the gut microbiota composition, improving nutrient absorption and reducing digestive disorders. Furthermore, studies have demonstrated that turmeric supplementation in layer diets can improve egg weight, shell quality, yolk colour and egg production rates. The mechanisms underlying these effects involve the antioxidant properties of turmeric, which protect the reproductive organs, enhance ovarian function and improve reproductive performance.

CONCLUSION

The findings underscore the potential of turmeric as a natural, cost-effective and sustainable intervention for improving layer well-being, egg quality and productivity. However, further research is needed to fully understand the mechanisms of action, optimize dosage regimens and evaluate the long-term effects of turmeric supplementation in layer diets.

A comparative study between curcumin and curcumin nanoparticles on reproductive performance and antioxidant system of aged roosters

Increased lipid peroxidation and decreased antioxidant status can result in reduced reproductive activity and fertility in aged male broiler breeders. This study was conducted to evaluate the effects of curcumin supplements (natural or nanoparticles) on the sperm characteristics, antioxidant system, fertility, and hatchability of aged roosters (54-64 wk), and to estimate the relative bioavailability value (RBV) of nano-curcumin on the measured parameters including the hypo-osmotic swelling test (HOST), motility, viability, sperm count, volume, the concentration of testosterone, glutathione peroxidase (GPx), and superoxide dismutase (SOD), diameter of the spermatogenic tube (DST), epithelium thickness (EpiTh), spermatogonia count (SPcount), fertility, hatchability, and relative weight of testis (RW-testis). A total of 30 roosters were individually caged and randomly assigned to 5 treatments comprising control (without curcumin as the basal diet), basal diet + 15 mg/kg curcumin (CUR15), basal diet + 30 mg/kg curcumin (CUR30), basal diet + 15 mg/kg nano-curcumin (Nano15), and basal diet + 30 mg/kg nano-curcumin (Nano30) for 10 wk. The slope ratio method was used to estimate the bioavailability of nano-curcumin by regressing each response on supplemental curcumin intake. Increasing dietary curcumin (P < 0.001) elicited a linear response to all studied traits. The RBV for volume, viability, motility, HOST, RW-testis, and GPx were estimated as 135 (CI: 115-156%), 143 (CI: 114-173%), 159 (CI: 122-196%), 132 (CI: 107-157%), 195 (CI: 126-264%), 176 (CI: 103-249%), and 178% (28-328%), respectively. Our findings revealed that curcumin nanoparticles enhance the reproductive efficiency of aged breeder roosters. In addition, the curcumin nanoparticles RBV exceeded that of natural curcumin, suggesting that lower concentrations of curcumin nanoparticles could have a significant effect on reproductive characteristics.

Effects of micelle silymarin in corn-soybean meal-based diet on laying hens' performance, egg quality, and blood profile, with comparative assessment of blood absorption rates between powdered and micelle silymarin

Micelle silymarin (MS) is recognized for its diverse range of beneficial properties, which encompass anti-inflammatory, antioxidant, hepatoprotective, and antidiabetic effects. The main objective of this study was to examine the effects of micelle silymarin on the performance, egg quality, blood profile, and absorption rate of silymarin in laying hens. In experiment 1: 288 Hy-Line brown laying hens, 28 wk old, were utilized for this experiment. The hens were randomly allocated into 3 dietary treatment groups, with each group comprising eight replicates of 12 hens, each housed in individual pens with access to feed and water. Over a 12-wk feeding trial, the hens were provided with a basal diet supplemented with different levels of MS: 0, 0.03, and 0.06%. In experiment 2: For this experiment, 192 Hy-Line Brown laying hens were divided into 2 dietary treatment groups, with each group comprising eight replications of 12 hens. The dietary treatments were: TRT1, basal diet + powder silymarin 4%; TRT2, basal diet + MS 4%. From the first experiment, the findings revealed that incorporating micelle silymarin (MS) into the hens' diet significantly increased egg weight at wk 6 (P < 0.05). Similarly, at wk 12 and throughout the entire experiment, significant effects were observed on downgraded egg count, egg production, egg weight, and feed conversion ratio (FCR) (P < 0.05). Moreover, Haugh Units (HU) and albumen height showed a linear improvement (P < 0.05) at wk 4 with MS supplementation. Furthermore, there was a linear increase in egg yolk color, albumen height, and eggshell thickness at wk 8 with MS supplementation (P < 0.05). Furthermore, a layers-fed diet supplemented with MS showed a linear increase (P < 0.05) in HU, egg weight, yolk color, albumen height, eggshell strength, and eggshell thickness in wk 12. Regarding blood profile parameters, the study revealed linear reductions for aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) (P < 0.05), whereas there was a tendency for albumin, triglyceride, and cholesterol (P < 0.10). In the second experiment, it was observed that the blood absorption rate of silymarin was higher in TRT2 compared to TRT1 at 2- and 4-h intervals following administration. In summary, increasing MS supplementation in the diet of laying hens enhanced egg production, egg quality, and blood profile. Additionally, silymarin absorption was higher in its micelle form than in its powder form.

Assessing the influence of micelle silymarin on laying hens' performance, egg quality, water loss and blood profile

Micelle silymarin (MS) is known for its various beneficial properties, including antiswelling, antioxidant, hepatoprotective and antidiabetic effects. The primary goal of this research was to investigate how MS impacts the performance, egg quality, water loss and blood profile of laying hens. 288 Hy-Line brown laying hens, 28 weeks in age, were utilized for this experiment. The hens were randomly allocated into three dietary treatment groups, with each group comprising eight replicates of 12 hens, each housed in individual pens with access to feed and water. Over a 12-week feeding trial, the hens were provided with a basal diet supplemented with different levels of MS: 0%, 0.03% and 0.06%. The results indicated that the inclusion of MS in the hens' diet did not have a significant impact on their performance (p > 0.05). However, Haugh units, egg weight and eggshell strength showed a linear improvement (p < 0.05) throughout the entire trial period with MS supplementation. Furthermore, there was a linear decrease in egg yolk colour and eggshell thickness showed linear improvements (p < 0.05), particularly during Week 8, with MS supplementation. Moreover, layers fed diet supplemented with MS showed a linear increased (p < 0.05) in albumen height and eggshell thickness in Week 12. In addition, egg water loss during Week 12, the third day of incubation, linearly decreased as an effect of the increasing level of the MS in the laying hen's diet (p < 0.05). Regarding blood profile parameters, the study revealed a tendency for alkaline phosphatase to decrease, whereas aspartate aminotransferase and cholesterol levels were linearly decreased (p < 0.05). In summary, increasing the level of MS supplementation in the diet of laying hens appeared to be beneficial in improving egg quality, slight improvement for egg water loss and certain aspects of blood profile parameters, without adversely affecting the hens' growth performance.

Dietary inclusion of micelle silymarin enhances egg production, quality, and lowers blood cholesterol in Hy-line brown laying hens

This study aimed to evaluate the effect of micelle silymarin (MS) supplementation on productive performance, egg quality, and blood biochemical parameters in laying hens. A total of 384 (Hy-Line brown, 28-week-old) laying hens were randomly distributed into one of four dietary treatment groups (eight replication per treatment; 12 hens per replicate) for a 12-week long feeding trial. Hens were fed a basal diet with the addition of 0%, 0.02%, 0.04%, and 0.06% of MS respectively. The results expressed that egg production percentage and egg weight were linearly (p < 0.05) enhanced at Weeks 0-6, 7-12, and 0-12, when 0%, 0.02%, 0.04%, and 0.06% of MS were added to laying hen diets. The feed conversion ratio and feed intake improved (p < 0.05) linearly at Weeks 0-6, 7-12, and 0-12 with increasing levels of MS supplementation in laying hens. The eggshell thickness and eggshell strength were linearly (p < 0.05) improved at weeks 4, 8, and 12 with an MS-supplemented diet. Additionally, eggshell colour, Haugh unit, and albumin height had no significant (p > 0.05) difference throughout the experimental period with different levels of MS-supplemented diet. The yolk colour of eggs showed significant (p < 0.05) differences at weeks 8 and 12 with levels of the MS-supplemented diet. However, at the end of the trial, the blood profile indicated that cholesterol levels decreased (p < 0.05) linearly, and triglyceride levels showed a tendency to decrease (p < 0.10) with MS supplementation. In conclusion, increasing the level of MS addition in the laying hen diet improved the egg production percentage and egg quality, reducing cholesterol levels in Hy-Line brown hens. However, this study indicates that MS can be added to the diet of laying hens up to 0.06% for improved egg production and egg quality.

The efficacy of polyphenols as an antioxidant agent: An updated review

Global production of the two major poultry products, meat and eggs, has increased quickly. This, in turn, indicates both the relatively low cost and the customers' desire for these secure and high-quality products. Natural feed additives have become increasingly popular to preserve and enhance the health and productivity of poultry and livestock. We consume a lot of polyphenols, which are a kind of micronutrient. These are phytochemicals with positive effects on cardiovascular, cognitive, anti-inflammatory, detoxifying, anti-tumor, anti-pathogen, a catalyst for growth, and immunomodulating functions, among extra health advantages. Furthermore, high quantities of polyphenols have unknown and occasionally unfavorable impacts on the digestive tract health, nutrient assimilation, the activity of digestive enzymes, vitamin and mineral assimilation, the performance of the laying hens, and the quality of the eggs. This review clarifies the numerous sources, categories, biological functions, potential limitations on usage, and effects of polyphenols on poultry performance, egg composition, exterior and interior quality traits.

Curcumin and curcumin nanoparticles counteract the biological and managemental stressors in poultry production: An updated review

Antibiotics have the potential to have both direct and indirect detrimental impacts on animal and human health. For instance, antibiotic residues and pathogenic resistance against the drug are very common in poultry because of antibiotics used in their feed. It is necessary to use natural feed additives as effective alternatives instead of synthetic antibiotics. Curcumin, a polyphenol compound one of the natural compounds from the rhizomes of turmeric (Curcuma spp.) and has been suggested to have several therapeutic benefits in the treatment of human diseases. Curcumin exhibited some positive responses such as growth promoter, antioxidant, antibacterial, antiviral, anticoccidial, anti-stress, and immune modulator activities. Curcumin played a pivotal role in regulating the structure of the intestinal microbiome for health promotion and the treatment of intestinal dysbiosis. It is suggested that curcumin alone or a combination with other feed additives could be a dietary strategy to improve poultry health and productivity.

Productive, physiological and nutritional responses of laying hens fed different dietary levels of turmeric powder

This study aimed to determine the impact of supplementation of turmeric powder on laying performance, egg quality, nutrient digestibility and some blood metabolites in laying hens. A total of one hundred and twenty Bovans Brown laying hens (55 weeks old) were assigned to one of four treatment diets (n = 30) for 12 weeks including turmeric powder at 0, 2.5, 5 or 7.5 g/kg respectively. The results revealed that egg production, egg weight and egg mass were significantly increased (p < 0.05), and the feed conversion ratio was significantly improved (p < 0.012) with increasing levels of turmeric in the laying hen diet. Egg thickness and Haugh unit were linearly increased (p < 0.01) with increasing supplementation levels. Moreover, compared with the control diet, the levels of turmeric powder supplementation significantly improved nutrient digestibility (p < 0.001). Moreover, the serum metabolic profile revealed that serum total cholesterol, aspartate aminotransferase, creatinine and urea concentrations were linearly decreased with increasing turmeric powder supplementation to hen diets. In conclusion, the inclusion of turmeric powder at 2.5, 5 or 7.5 g/kg diet improved egg production, nutrient digestibility, egg quality and serum metabolic profile and may be used as a feed additive in laying hens' nutrition. However, results indicate that the best improvement was observed when 5 g/kg were supplemented.

The association of Curcuma and Scutellaria plant extracts improves laying hen thermal tolerance and egg oxidative stability and quality under heat stress conditions

Chronic exposure to high ambient temperatures is detrimental to laying hen performance and egg quality. Plant secondary metabolites may alleviate effects, partly due to their antioxidant activities. Herein, we investigated the effects of dietary supplementation with a phytonutrient solution (PHYTO) consisting of a plant extract combination of Scutellaria baicalensis and Curcuma longa on young layers (25–32 wk of age) raised under naturally elevated temperature conditions. Four hundred, 24-wk-old Lohmann hens were allocated in 50 cages and, after a week of adaptation, were offered a diet either containing 2 g/kg of PHYTO or not, for 8 wk. Hen BW was measured at the beginning and end of the trial, and egg production and feed intake were recorded weekly. At week 32, four eggs per cage were collected to determine egg quality characteristics as well as the rate of lipid and albumen oxidation in fresh eggs. At the end of the trial, two hens per cage were blood sampled for assessment of biochemical markers, one of which was euthanized for histopathological evaluation of the liver and intestine and assessment of intestinal histomorphometry. The herbal mixture supplementation significantly increased egg production rate at weeks 28 and 29 and for the overall production period, and feed efficiency at weeks 26–29. In addition, the degree of liver necrosis and microvascular thrombosis was lower (P < 0.05) whereas intestinal villosity was greater in duodenal and jejunal segments (P < 0.05) in the PHYTO compared to the control group. Supplementation also reduced (P < 0.05) blood concentrations of corticosterone, alanine aminotransferase activity, and TBARS, and a reduction in catalase activity was observed. Egg quality characteristics were not affected, except for eggshell thickness, egg diameter, and eggshell breaking strength that were superior in the PHYTO group (P < 0.05). PHYTO supplementation significantly improved egg lipid oxidation status of fresh eggs. In conclusion, supplementation with PHYTO improved laying hen productivity and egg quality, which was associated with an improvement in laying hen thermotolerance.

Impacts of polyphenols on laying hens' productivity and egg quality: A review

There has been a rapid increase in the world's output of main poultry products (meat and eggs). This reflects customer desire for these high-quality and safe products and the comparatively low price. Recently, natural feed additives, plants and products have been increasingly popular in the poultry and livestock industries to maintain and improve their health and production. Polyphenols are a type of micronutrient that is plentiful in our diet. They are phytochemicals that have health benefits, notably cardiovascular, cognitive function, antioxidant, anti-mutagenic, anti-inflammatory, antistress, anti-tumour, anti-pathogen, detoxification, growth-promoting and immunomodulating activities. On the other hand, excessive polyphenol levels have an unclear and sometimes negative impact on gastrointestinal tract health, nutrient digestion, digestive enzyme activity, vitamin, mineral absorption, laying hens performance and egg quality. As a result, this review illuminated polyphenols' various sources, classifications, biological activities, potential usage restrictions and effects on poultry, layer productivity and egg external and internal quality.

Hepatic fatty acids profile, oxidative stability and egg quality traits ameliorated by supplementation of alternative lipid sources and milk thistle meal

This study assessed the effects of different levels of milk thistle (Silybum marianum) meal (MTM) on egg quality traits, oxidative stability, blood biochemical parameters and liver health indices in laying hens receiving diets supplemented with lipid from different sources. For this purpose, Leghorn laying hens (Hy-Line W-36) were randomly assigned to 12 experimental treatments with eight replicates of five birds each. Dietary treatments consisted of four dietary fat sources (fish oil, sunflower oil, poultry oil and fat powder, each with different fatty acid profiles) and three levels of MTM (0.0, 15 and 30 g/kg) offered through 10 days of adaptation and 70 days of main recording. Results showed that dietary inclusion of polyunsaturated fatty acids, including fish or sunflower oils, reduced serum cholesterol content but increased blood malondialdehyde (MDA) concentration (p < 0.05). While fish oil improved the yolk colour index and Haugh unit (p < 0.05), it decreased yolk cholesterol concentration (p < 0.01). The highest hepatic glycogen content and tissue integrity as well as the lowest liver lipid percentage and MDA content were observed in birds fed diets supplemented with poultry oil. On the other hand, feeding 30 g/kg of MTM reduced not only hepatic lipid percentage but also aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities (p < 0.01), while it improved eggshell strength and thickness (p < 0.05). Supplementation of fat powder enhanced hepatic C16:0 content, while addition of poultry, sunflower or fish oil increased C18:1, C18:2 or C20:5 concentrations respectively (p < 0.01); nonetheless, feeding the highest level of MTM reduced hepatic ΣSFA but increased Σn-3 fatty acids (p < 0.01). The interaction effects indicated that fish or sunflower oil supplementation increased the MTM level required to reduce not only serum or egg cholesterol concentrations (p < 0.05) but also blood or hepatic MDA content (p < 0.01). It was concluded that fish oil and MTM (30 g/kg) supplements might improve internal egg quality traits and eggshell quality respectively. The hepatic fatty acid profile was also found strongly correlated with dietary fatty acids. Finally, the best hepatic health indices and the highest oxidative stability were achieved when the birds were fed diets supplemented with poultry oil and 30 g/kg of MTM.

Sanguinarine improved nutrient digestibility, hepatic health indices and productive performance in laying hens fed low crude protein diets

A major mean to minimize feeding costs and faecal nitrogen excretion on poultry farms is to decrease the supplied dietary protein content. This, however, is associated with the declines in productive performance and systemic health indices. Sanguinarine may improve protein efficiency via decreasing the intestinal amino acid decarboxylation and stimulating the tryptophan‐serotonin pathway. The present study was carried out to investigate the effects of dietary supplementation of sanguinarine on the performance, egg yolk biochemical parameters, serum enzyme activities, nutrient digestibility, ovarian follicles, and hepatic health indices in laying hens fed decremental levels of crude protein (CP). For this purpose, 180 laying hens were allocated into nine dietary treatments with four replicates of five birds each. The experimental treatments consisted of three levels of CP (85.0%, 92.5%, and 100% of Hy‐Line W‐36 manual recommendation) and three levels of sanguinarine (0.00, 3.75, and 7.50 mg/kg) in a 3 × 3 factorial arrangement administered during a 70‐day feeding trial. Results showed that the decremental levels of CP led to significant increases in serum aspartate aminotransferase (p < .05), alanine aminotransferase, and alkaline phosphatase (p < .01) activities, egg yolk cholesterol concentration (p = .064), and hepatic fat and malondialdehyde (MDA) contents (p < .05). It also caused the significant declines in ileal dry matter (DM) digestibility (p < .05) and eggshell strength (p < .05), and also tended to decrease CP digestibility (p = .071), Haugh unit (p = .057) and egg production percentage (p = .062). The interaction effects of the experimental factors indicated that dietary supplementation of sanguinarine, especially at 7.50 mg/kg, led to significant improvements in serum aspartate aminotransferase and alanine aminotransferase activities (p < .01), egg yolk cholesterol (p < .001) and triglyceride (p < .05) concentrations, eggshell strength (p < .001), Haugh unit (p < .05), hepatic fat (p < .001) and MDA (p = .059) contents, ileal DM and CP digestibility (p < .01) as well as egg production, egg mass and feed conversion ratio (FCR; p < .05) in birds receiving decremental levels of CP. Taken together, the results indicate that dietary administration of sanguinarine could enhance productive performance via improving nutrient digestibility, hepatic health indices and fortifying systemic antioxidant capacity in laying hens fed low‐CP diets.

Curcumin, Curcumin Nanoparticles and Curcumin Nanospheres: A Review on Their Pharmacodynamics Based on Monogastric Farm Animal, Poultry and Fish Nutrition

Nanotechnology is an emerging field of science that is widely used in medical sciences. However, it has limited uses in monogastric farm animal as well as fish and poultry nutrition. There are some works that have been done on curcumin and curcumin nanoparticles as pharmaceutics in animal nutrition. However, studies have shown that ingestion of curcumin or curcumin nanoparticles does not benefit the animal health much due to their lower bioavailability, which may result because of low absorption, quick metabolism and speedy elimination of curcumin from the animal body. For these reasons, advanced formulations of curcumin are needed. Curcumin nanospheres is a newly evolved field of nanobiotechnology which may have beneficial effects in terms of growth increment, anti-microbial, anti-inflammatory and neuroprotective effects on animal and fish health by means of nanosphere forms that are biodegradable and biocompatible. Thus, this review aims to highlight the potential application of curcumin, curcumin nanoparticles and curcumin nanospheres in the field of monogastric farm animal, poultry and fish nutrition. We do believe that the review provides the perceptual vision for the future development of curcumin, curcumin nanoparticles and curcumin nanospheres and their applications in monogastric farm animal, poultry and fish nutrition.

Effects of dietary glycerol monolaurate on productive performance, egg quality, serum biochemical indices, and intestinal morphology of laying hens

Glycerol monolaurate (GML) has been widely used as an effective antibacterial emulsifier in the food industry. A total of 360 44-week-old Hy-Line brown laying hens were randomly distributed into four groups each with six replicates of 15 birds, and fed with corn-soybean-meal-based diets supplemented with 0, 0.15, 0.30, and 0.45 g/kg GML, respectively. Our results showed that 0.15, 0.30, and 0.45 g/kg GML treatments significantly decreased feed conversion ratios (FCRs) by 2.65%, 7.08%, and 3.54%, respectively, and significantly increased the laying rates and average egg weights. For egg quality, GML drastically increased albumen height and Haugh units, and enhanced yolk color. Notably, GML increased the concentrations of polyunsaturated and monounsaturated fatty acids and reduced the concentration of total saturated fatty acids in the yolk. The albumen composition was also significantly modified, with an increase of 1.02% in total protein content, and increased contents of His (4.55%) and Glu (2.02%) under the 0.30 g/kg GML treatment. Additionally, GML treatments had positive effects on the lipid metabolism of laying hens, including lowering the serum triglyceride and total cholesterol levels and reducing fat deposition in abdominal adipose tissue. Intestinal morphology was also improved by GML treatment, with increased villus length and villus height to crypt depth ratio. Our data demonstrated that GML supplementation of laying hens could have beneficial effects on both their productivity and physiological properties, which indicates the potential application of GML as a functional feed additive and gives us a new insight into this traditional food additive.

Efficacy of essential oils combination on performance, ileal bacterial counts, intestinal histology and immunocompetence of laying hens fed alternative lipid sources

This study was carried out to assess the effects of a blend of herbal essential oils (namely Thymus vulgaris, Mentha piperita, Rosmarinus offisinalis and Anethum graveolens) and different dietary lipid sources on the performance, ileal bacterial enumeration, intestinal histological alterations and immune responses in laying hens. For this purpose, a total of 150 laying hens were randomly allocated to six experimental treatments with five replicates of five birds each. Dietary treatments consisted of three levels of a mixture of essential oils (0, 100 and 200 mg/kg) and two sources of lipid (soybean oil and fish oil containing different ratios of n-6 to n-3 fatty acids) fed to the animals during an 80-days feeding trial. Findings indicated that dietary administration of fish oil not only increased significantly the spleen relative weight (p < 0.01) and the antibody titre against Newcastle virus (p < 0.05) but also led to reductions in liver relative weight (p < 0.05) and feed conversion ratio (p < 0.05). Moreover, the mixture of herbal essential oils brought about declines in hepatic relative weight, heterophile to lymphocyte ratio (p < 0.05) and intestinal pathogen populations (p < 0.01). Mention must also be made of the improvements it made in spleen weight (p < 0.01), antibody titres against SRBC (p < 0.01) and Newcastle virus (p < 0.05), villus height to crypt depth ratio (p < 0.01), goblet cell numbers (p < 0.05), lamina propria lymphatic follicle diameters (p < 0.01) and feed conversion ratio (p = 0.06). It may be claimed that the enhancements observed in the performance of laying hens fed fish oil and 200 mg/kg of the blend of essential oils could have potentially been associated with improved intestinal health indices as well as cellular and humoral immune responses.