Eggshell Content Research Articles

Experimental study on preparation of fly ash-based geopolymer blended with recycled calcium source

A large amount of waste eggshells raises environmental issues. This study uses eggshells as recycled calcium source to synthesize fly ash and eggshell geopolymer (FAEG). The effects of eggshell content, liquid-solid ratio, NaOH/Na2SiO3 ratio, and NaOH solution concentration on the strength of the FAEG were evaluated by unconfined compressive strength (UCS) test. The geopolymerization products and microstructure characteristics of the FAEG were analyzed by XRD, FTIR, TGA, and SEM test. The results show that eggshells acted as recycled calcium sources are capable of significantly enhancing the UCS of the FAEG. The optimal content of eggshells is 15%. The NaOH/Na2SiO3 ratio has a significant effect on the UCS of the FAEG, while the influence of liquid-solid ratio and NaOH concentration is slight. The optimal NaOH/Na2SiO3 ratio is 50:50 and the liquid-solid ratio is recommended to be 0.55. Eggshells take part in the geopolymerization by acting as a precipitating and seeding element in the reaction and favoring the generation of the geopolymeric gels in the FAEG.

Investigation of the mechanical, thermal and wear properties of eggshell/PLA composites

Abstract The current study investigated the potential application of agricultural waste chicken eggshell (CES) as a reinforcement in composites made of poly (lactic acid) (PLA). With the use of twin extruder and injection molding machine, polymer composites have been developed. The performance of the composites was assessed with respect to its mechanical, thermal, and wear properties. It was shown that the increase in eggshell content led to the increase in void content and water absorption. Despite the increase in void content, the mechanical properties, in particular, micro-hardness, tensile strength and flexural strength were significantly improved. Conversely, when the eggshell content increased from 0 to 30 wt%, the impact strength was decreased. A slight decrease in fracture toughness was observed. Thermal properties, such as thermal stability and thermal degradation temperature, were improved with an increase in eggshell content. PLA, PLA-CES-10, PLA-CES-20, and PLA-CES-30 composites exhibited increase in erosion rate by 13.8 %, 10 %, 9 %, and 6 %, respectively, when the impact velocity was increased from 30 m/s to 50 m/s. Data were analyzed statistically with one-way ANOVA and post hoc Tukey’s HSD test (α < 0.05). Overall, PLA/eggshell based polymer composites performed exceptionally well, in addition to their environmental benefits, pollution control, waste utilization, and reduced production cost.

Fabrication of Functional Gypsum Boards Using Waste Eggshells to Prevent Sick Building Syndrome

Eggshells can adsorb chemicals, but no studies regarding the adsorption of gaseous chemicals using eggshells or eggshell membranes have been reported. The purpose of this study was to apply chemical adsorption using eggshells to the maintenance of human health. Building materials containing eggshells may reduce the concentrations of toxic substances, such as formaldehyde, via the adsorption functions of eggshells. In the bending study, the strength of board-shaped gypsum-containing eggshells was not compromised when the content of eggshells within the gypsum was ≤10%. Compared to those of gypsum boards containing seashells, which comprise calcium carbonate, similar to eggshells, gypsum containing eggshells displayed a higher strength. In the adsorption study, board-shaped gypsum containing eggshells placed inside a sealed box rapidly decreased the formaldehyde concentration. A gypsum board with an eggshell content of ≥5% could limit the formaldehyde concentration to ≤0.08 ppm. Furthermore, the results were compared with those of adsorption studies using plasterboard mixed with other natural materials. Eggshells displayed excellent functionalities as novel formaldehyde adsorbents.

Stabilization of zirconia nanoparticles by collagen protein and calcium carbonate extracted from eggshell and its biodegradation, radical scavenging and mineralization activity

In this current study,collagen protein extracted from eggshell membrane and calcium carbonate (a main component of eggshell) are used as additive to enhance the stability and hardness of the zirconia crystals. Five different samples are prepared by adding membrane containing eggshell content as, 1 g, 2 g, 3 g, 4 g and 5 g in aqueous zirconium oxychloride sol. Phase purity is confirmed by XRD and FTIR. Phase pure and dense particles divulges the high hardness (∼1389 HV) and fracture toughness (12.89 MPa m1/2).FESEManalysis illustrates the formation of dense, well separated, non-agglomerated and spherical nanoparticles at 5 g of eggshell content. Eggshell works as a surfactant and stabilizer for formation of phase pure tetragonal spherical nanoparticles. Biodegradation study of optimized tetragonal zirconia (t-ZrO2)in phosphate buffered saline (PBS) presents that minor change in weight and hardness after 72 h of immersion. Antioxidant study shows the 96% of radical scavenging activity (RSA). In vitro bio-mineralization study shows the formation of new bone after 5 weeks. After 5 weeks all pores were filled and minerals were deposited on the surface of the scaffolds. SEM images confirms that eggshell-zirconia composite form new bone. So eggshell addition results in formation of phase pure t-ZrO2 nanoparticles with well-defined boundaries which exhibit higher hardness, fracture toughness, stability and enhanced antioxidant properties.

Limbah Cangkang Telur Sebagai Inovasi Material Pengganti Agregat Halus Beton

Eggshells become a huge waste and cause various environmental problems. One of the efforts that can be made to reduce this waste is to use it as a material in concrete. Cement and fine aggregate raw materials that are continuously used will eventually run out and are difficult to renew. This study aims to determine the slump value and compressive strength using eggshell waste as a substitute for cement and fine aggregate in concrete. Eggshells as a substitute for cement were in the oven at 105°C for 24 hours and then fired and the material that passed the No. sieve was taken. 200 (75 µm) and sieve number 4 for fine aggregate. The percentage of mixed eggshell content used was 0%, 5%, 10%, and 15%. The results showed that the slump and compressive strength decreased with increasing eggshell content in the concrete. This is caused by the size of the eggshell. The use of egg shells with a size of 4.75 mm as a substitute for fine aggregate is not recommended for concrete. The irregular shape of the eggshell is considered less capable of filling cavities and even causing cavities in concrete. The right size for using egg shells is in the range of 0.5 – 1 mm. Referring to these results, this study highlights the importance of choosing eggshell size as a substitute for fine aggregate. So that with proper utilization, egg shells can be utilized as a material substitute and improve the quality of concrete.

Review of the Benefits of Eggshell Content in Body Tissue Structure Repair

Eggshell (ES) is a waste material that cannot be consumed with low economic value. ES mainly contains calcium carbonate (CaCO3) and an organic matrix in the form of proteins, glycoproteins, and proteoglycans. Meanwhile, the eggshell membrane (ESM) contains osteopontin collagen, fibronectin, keratin, histones, avian beta defensins, ovocalyxin-36, apolipoproteins, protocadherin, chondroitin sulfate, ovotransferrin, hyaluronic acid, and sialic acid as well as various amino acids. Recently, ES has been widely used in industry, agriculture, food, and medical fields. The potential of ES in the medical field is interesting to discuss, especially in relation to tissue repair. Efforts to reduce the prevalence of wounds that generally originate from acute wounds but become chronic due to various factors that are neglected in their management. In particular, this review will describe the benefits of ES content in repairing body tissues. ES-derived active ingredients such as CaCO3, brushite, and hydroxyapatite exhibit osteoconductive properties that promote bone regeneration. Calcium ions can increase insulin and leptin sensitivity in the liver and can induce repair of acute kidney injury. Meanwhile, ESM contributes positively to neural tissue repair and plays an important role in wound healing, response to external stimuli, defense response, inflammatory response, cell-substrate adhesion, promoting cell growth, migration, differentiation, and tissue remodeling.

Analysis and prediction of abrasion wear properties of glass–epoxy composites filled with eggshell powder

Eggshell is a by-product of the poultry industry and a common kitchen waste. Being rich in calcium, it can be used as a potential reinforcing agent for fabricating wear-resistant polymer composites. The present research uses the conventional hand-lay-up technique to fabricate hybrid glass-epoxy composites consisting of 0, 5, 10, 15, and 20 wt.% of eggshell powder, respectively. The prepared composites are characterized by their physical and mechanical properties. Dry-sliding wear trials on the composite samples are conducted as per Taguchi's L25 design following ASTM G99 05. The results revealed that while the density and volume fraction of voids and resistance to wear of the glass-epoxy composites increase with the eggshell content, the mechanical strength values decrease. The analysis of wear test results concluded that the control factors like filler content and sliding velocity significantly affect the wear rate, but the effect of abrasion distance and normal load is very marginal. Based on the experimental outcomes, a predictive model working on fuzzy logic is implemented to predict the specific wear rate (SWR) of the composites at a wide range of significant control factors within the test domain. It is observed that the SWR increases with sliding velocity and decreases with filler content. The analysis resulted in the optimal factor setting as sliding velocity 30 cm/s, abrasion distance 300 m, normal load 5 N, and eggshell content 20 wt.%, which are responsible for the minimum wear. Further, the mechanisms of wear loss have been studied using a scanning electron microscope.

Compressive behavior of Habesha eggshell particulate reinforced epoxy composites

AbstractEnvironmental pollution has become one of the major challenges to overcome in recent decades. Disposing waste materials has caused great concern by creating a landfill burden and increased environmental pollution. Utilizing or recycling wastes is one of the approaches considered that could bring positive environmental and economic benefits. Eggshells are among the understated waste materials that have great potential to impact the material world. In the present work, Habesha eggshells native to Ethiopia are utilized to prepare epoxy based composites. Five types of composites by varying the Habesha eggshell content (0, 2.5, 5, 7.5, and 10 vol%) are investigated. Physical characterization in terms of density and void content estimations, and eggshell particle size analysis are carried out. Mechanical characterization in terms of normal and quasi‐static compression tests are performed. Results infer the density of eggshell particles to increase with increasing eggshell content, while quasi‐static compression tests infer that modulus and strength of eggshell/epoxy composites are sensitive to variations in the strain rate. However, irrespective of the strain rates, all the eggshell/epoxy composites depict higher modulus as compared with neat epoxy specimens. At 1.43, 0.1, and 0.001 strain rates, increase in modulus of composites are in the range of 17%–57%, 3%–107%, 30%–114%, respectively. Further, compressive yield strength of all the Habesha eggshell/epoxy composites is low compared with epoxy specimens for all the strain rates investigated. Scanning electron micrographs of test specimens for different loading conditions reveal reinforcing egg shell particles assists in absorbing the loading effectively.

Preparation, characterization, and physicomechanical properties of glass-ceramic foams based on alkali-activation and sintering of zeolite-poor rock and eggshell

This study reports the fabrication of novel glass-ceramic foams for thermal insulation to minimize the energy consumption in the buildings. Different combinations of zeolite-poor rock/eggshell powders (with eggshell content varying from 0 to 20 wt%) have been used to produce the foams through alkali-activation and reactive sintering techniques. The produced glass-ceramic foams were characterized based on their structural, thermal, and mechanical characteristics. The heat treatment process and the foaming patterns are examined by a heating microscope, and the findings reveal an excellent foamability of the utilized alkali-activated mixture in the range of 800–950 °C. The microstructure and the pore size of the acquired foams are investigated using a scanning electron microscope (SEM) and computed tomography (CT) analysis. The crystallinity and phase composition of the prepared samples were investigated via X-ray diffraction (XRD). The experiment findings reveal that raising the eggshell content is favorable to gas production, but it affects the liquid phase creation resulting in inconsistent pore size distribution. The appropriate eggshell content is 4%, and the optimal heat treatment temperature is 900 °C. The produced ceramic foams possess a density ranging from 0.54 to 1 g/cm3, thermal conductivity around 0.07–0.4 W/mK, and compressive strength values between 1.2 and 6.7 MPa. The results indicate that the ceramic foams created could be a feasible choice for applications in constriction as thermal insulation materials.

EIS Investigation of the Corrosion Behavior of Steel Bars Embedded into Modified Concretes with Eggshell Contents

This investigation is focused on evaluation of the corrosion behavior of embedded steel bars (SB) into concretes. Conventional and modified concretes with eggshell are prepared. Although the effect of calcium carbonate on mechanical behavior is recognized and reported, their effects as eggshell (ES) particles replacing portions of sand and cement contents are reasonably scarce. Corrosion behavior is evaluated by electrochemical impedance spectroscopy (EIS) and the potentiodynamic polarization technique. Equivalent circuit and porous electrode behavior are also considered. The novelty concerns a promising use of concrete with ES content to maintain corrosion resistance concatenated with reasonable structural properties. For this purpose, three distinct concrete mixtures are proposed, i.e., a reference and two modified concretes. One replaces 10 wt.% with cement and another 10 wt.% with sand content. It is found that porous electrode behavior helps to predict the corrosion mechanism. Finer ES particles in concrete mixture provides a rapidly passivation on rebar. This reflects positively in corrosion current density after long-term immersion. Additionally, an environmentally friendly aspect associated with economical factor constitutes a promise use of the concrete.

Gravimetric (Corrosion) Study of Carbonaceous Agro-Waste Inhibitor on the Al-Fe-Si alloy (AA8011) in aggressive Nitric (NO3 -) Environment

The inhibition potential and adsorption properties of agro-waste eggshell (EGS) product on Al-Fe-Si alloy in 0.5 M HNO3 was examined in this novel work. The gravimetric weight-loss measurement was utilized to check the rate of corrosion attack in reference to the time of immersion and the potency of the EGS inhibitor. In this work, the mechanism of the inhibitor adsorption on the AA8011 alloy surface was as well checked to understand the degree of the adherence of the adsorbate to the surface of the metal. The results of the weight loss analysis revealed a reduction in the weight loss and the rate of corrosion in the presence of the green inhibitor. The efficiency of the EGS inhibitor increases with percentage rise in EGS content but decline with time progression, however, the 2 g EGS content maintains good efficiency of about 71.591% at the end of 168 hours. The best regression coefficient of R2 = 0.99088 was achieved from the Langmuir isotherm model and physical adsorption was confirmed from the evaluation of the adsorption free energy (ΔG°ads).

Effects of Caffeine on Egg Quality and Performance of Laying Hens.

This study's objective was to determine the effects of caffeine intake at various levels, incorporated in the layers' food, on performance and egg quality of hens. A total of 576 hens, aged 56 weeks, were used. The layers were fed rations containing 0 (control), 150, 300, or 450 ppm of caffeine for 12 weeks. During the experimental period, performance parameters (weight, feed consumption, and livability) and egg production and quality (weight, Haugh unit, percentages of yolk, albumen and eggshell, yolk color, eggshell thickness, and resistance, and calcium and phosphorus eggshell contents) were evaluated. The highest concentration of caffeine in the diet (450 ppm) promoted a significant increase in the mortality of hens (1.45% per week) compared to controls (0.23%). There was a reduction in feed consumption by hens, decreased egg production, and reduced eggshell thickness and percentage, with the increase of caffeine. The egg yolk percentage was increased, and the eggshell percentage was reduced in the groups treated with 300 and 450 ppm of caffeine. Furthermore, reduced eggshell thickness was found in all groups that received caffeine. However, it was found that 150 ppm of caffeine in the food did not cause significant changes in most egg production and quality parameters. In summary, caffeine consumption by laying hens increased mortality rate and promoted deleterious effects on chicken production and egg quality at concentrations of 300 and 450 ppm.

Impact Strength, Flexural Modulus and Wear Rate of PMMA Composites Reinforced by Eggshell Powders

In the present study, the impact strength, flexural modulus, and wear rate of poly methyl methacrylate (PMMA) with eggshell powder (ESP) composites have been investigated. The PMMA used as a matrix material reinforced with ESP at two different states (including untreated eggshell powder (UTESP) and treated eggshell powder (TESP)). Both UTESP and TESP were mixed with PMMA at different weight fractions ranged from (1-5) wt.%. The results revealed that the mechanical properties of the PMMA/ESP composites were enhanced steadily with increasing eggshell contents. The samples with 5 wt.% of UTESP and TESP additions give the maximum values of impact strength, about twice the value of the pure PMMA sample. The calcination process of eggshells powders gives better properties of the PMMA samples compared with the UTESP at the same weight fraction due to improvements in the interface bond between the matrix and particles. The wear characteristics of the PMMA composites decrease by about 57% with increases the weight fraction of TESP up to 5 wt.%. The flexural modulus values are slightly enhanced by increasing of the ESP contents in the PMMA composites.

Egg Shell Powder Reinforced Polypropylene (PP)Composite: Effect of Mechanical and Heat Capacity

The mechanical properties of Polypropylene (PP): Egg Shell powder composite was assessed with respect to the effect of filler content shells powder Egg varying from 1% to 10% by weight of the composite. Apparent amelioration in the mechanical parameters has recorded best ratios 5% and 7% weight. The mechanical properties of prepared film have examined through diverse parameters concerning the elastic deformity based on calculated the load – elongation properties. The conduct of the stress - strain curve was investigated in terms of the cold drawing model. The elastic behavior decreased at 5% composite Egg Shell powder. The specific heat capacity of Polypropylene, obvious an increase of the composite specific heat capacity using egg shell content.

Investigating the Ability of Using Eggshell Powder as a Filler in Hot Mix Asphalt Mixture

Nowadays, many studies have been conducted to find low cost waste materials that can be used in asphalt mixtures. Therefore, the idea of this study involves using one of these waste materials, which is Eggshell. Moreover, evaluate the ability to use eggshell powder, in hot mix asphalt mixtures as filler is the main objective of this study. This research was conducted by comparing the performance of mixtures of different eggshell powder percentages, 0, 3, 6, 9, 12, 15, 20, 25 and 100% and finding optimal eggshell content (OESC). To achieve this objective, Asphalt concrete mixtures, were prepared, and subjected to a series of laboratory experiments. Stability, flow, bulk density and indirect tensile strength are the experiments that have been implemented. In addition, the materials used are: - asphalt cement, Portland cement, chicken eggshell, coarse aggregate, fine aggregate. Where, eggshell powder used as an alternative to Portland cement in a part or as a replacement to cement. For all tests made in this study, the comparison is made against the conventional specimen with optimum asphalt content (found to be 4.85% for wearing layer) to find an optimum blend mixture of eggshell. The results showed that the effective eggshell content was 6% and the eggshell is one of the substances that can be used as a filler in asphalt mixture blend and realize Iraqi specifications. Furthermore, money can be saved by using this low-cost material instead of cement. For 6% ESP content rate, the stability & flow values has been checked with Iraqi specifications and showed that 6% ESP was the best ratio which has (12.83 KN) stability and (2.45) mm flow values. Higher density was found at 6% ESP and it has (2.32 gm/cm3). The results of indirect tensile strength (ITS) of 6% ESP showed reduction in ITS than 0% ESP specimen. While Tensile strength ratio (TSR) of 6% ESP is higher than 0% ESP that is (95.16 %) & (87.88 %) respectively, therefore 6% ESP specimen is better than the other by resistance to moisture damage.

Estimation of calcium requirements for optimal productive and reproductive performance, eggshell and tibial quality in egg-type duck breeders

Optimizing the dietary calcium (Ca) level is essential to maximize the eggshell quality, egg production and bone formation in poultry. This study aimed to establish the Ca requirements of egg-type duck breeders from 23 to 57 weeks of age on egg production, eggshell, incubation, tibial, plasma and ovary-related indices, as well as the expression of matrix protein-related genes. Totally, 450 Longyan duck breeders aged 21 weeks of age were allotted randomly into five treatments, each with six replicates of 15 individually caged birds. The data collection started from 23 weeks of age and continued over the following 35 weeks. The five groups corresponded to five dietary treatments containing either 2.8%, 3.2%, 3.6%, 4.0% or 4.4% Ca. The tested dietary Ca levels increased (linear, P <0.01) egg production and egg mass, and linearly improved (P <0.01) the feed conversion ratio (FCR). Increasing the dietary Ca levels from 2.8% to 4.4% increased (P <0.01) the eggshell thickness and eggshell content. The tested Ca levels showed a quadratic effect on eggshell thickness and ovarian weight (P <0.01); the highest values were obtained with the Ca levels 4.0% and 3.6%, respectively. Dietary Ca levels affected the small yellow follicles (SYF) number and SYF weight/ovarian weight, and the linear response (P <0.01) was significant vis-à-vis SYF number. In addition, dietary Ca levels increased (P <0.05) the tibial dry weight, breaking strength, mineral density and ash content. Plasma and tibial phosphorus concentration exhibited a quadratic (P <0.01) response to dietary Ca levels. Plasma calcitonin concentration linearly (P <0.01) increased as dietary Ca levels increased. The relative expression of carbonic anhydrase 2 in the uterus rose (P <0.01) with the increment of dietary Ca levels, and the highest value was obtained with 3.2% Ca. In conclusion, Longyan duck breeders fed a diet with 4.0% Ca had superior eggshell and tibial quality, while those fed a diet with 3.6% Ca had the heaviest ovarian weights. The regression model indicated that the dietary Ca levels 3.86%, 3.48% and 4.00% are optimal levels to obtain maximum eggshell thickness, ovarian weight and tibial mineral density, respectively.

Influence of graded inclusion of white lupin (Lupinus albus) meal on performance, nutrient digestibility and ileal viscosity of laying hens

ABSTRACT1. The aim of this study was to investigate the effect of white lupin (Lupinus albus) meal (WLM) addition on the intestinal viscosity, bird performance and nutrient utilisation of laying hens.2. The experiment was conducted with 360 laying hens aged 21 weeks fed one of 6 treatments, including a corn-soybean meal control diet (CON) and 5 experimental diets containing 60, 120, 180, 240 and 300 g/kg WLM.3. A linear increase in feed intake (p < 0.001) was observed with higher levels of WLM from 0 to 300 g/kg. Laying rate decreased quadratically (p < 0.05) and egg weight (at 6th, 12th and 18th weeks of the trial) decreased linearly with WLM inclusion from 0 to 300 g/kg. Birds fed 60 g/kg or more of WLM laid lighter eggs (p < 0.05) than CON hens. When 240 g/kg or more WLM was included into the diet, laying rate was affected negatively (p < 0.05).4. As WLM increased from 0 to 300 g/kg, apparent metabolisable energy and pre-caecal digestibility of dry matter and crude protein decreased quadratically (p < 0.05). When 300 g/kg of WLM was used, there was a tendency (p < 0.1) to decrease pre-caecal starch digestibility. WLM dose exerted a quadratic effect (p < 0.05) on total sialic acid excretion. As WLM increased, the viscosity of ileal digesta linearly increased (p < 0.05).5. In the 6th and 12th weeks of the experiment (p < 0.05), eggshell thickness decreased linearly when 240 g/kg of WLM was added. At the 6th, 12th and 18th weeks, a linear decrease in eggshell content was observed (p < 0.05) after WLM addition.6. In conclusion, the graded inclusion of WLM into laying hens’ diets resulted in depressed performance, AMEN and eggshell quality.

Eggshell as a partial cement replacement in concrete development

Research on the reuse of waste materials in the concrete industry has been quite intensive in the past decade. The objective of this research is to identify the performance of oven-dried eggshell powder as a partial cement replacement in the production of concrete under both water-cured and air-cured regimes. Eggshell powder of various amounts, namely 5%, 10%, 15% and 20% by volume, was added as a replacement for ordinary Portland cement. The results showed that water-cured eggshell concrete greatly improved the compressive and flexural strength of concrete, by up to 51·1% and 57·8%, respectively. The rate of water absorption of eggshell concrete was reduced by approximately 50%, as eggshell powder filled up the existing voids, making it more impermeable. However, the compressive strength of the eggshell concrete decreases gradually when the amount of eggshell powder increased, during immersion in acid and alkali solutions, because eggshell contains a high amount of calcium, which reacts readily with acid and alkali solutions. As the eggshell content increases, the solution reacts with the paste so the bonding of the paste reduces, and therefore the strength also reduces. The reduction of compressive strength during immersion in sulphuric solution and sodium sulphate solution was 27·5% and 31·2%, respectively, when 20% eggshell powder was used to replace cement. It can be concluded that the optimum percentage of oven-dried eggshell powder as a partial cement replacement is 15%.

Ideal digestible isoleucine: digestible lysine ratio in diets for laying hens aged 24-40 weeks

Two hundred fifty-two Hy-Line W36 laying hens were allotted in a randomized block design with 6 treatments, 7 replicates and 6 hens per experimental unit in order to determine the ideal digestible isoleucine: digestible lysine (Ile:Lys) ratio for laying hens aged 24-40 weeks. Experimental diets contained 5.92, 6.33, 6.73, 7.14, 7.54 and 7.95 g/kg of digestible isoleucine, resulting in different Ile:Lys ratios (0.73:1, 0.78:1, 0.83:1, 0.88:1, 0.93:1 and 0.98:1). Experimental diets were isonitrogenous, with different dietary contents of glutamic acid, and made isocaloric by adjusting the levels of cornstarch. All essential amino acids were provided proportionally to digestible lysine. Feed intake, egg production, egg weight, egg mass, feed conversion ratio per egg mass, feed conversion ratio per dozen eggs, albumen, yolk and eggshell content were assessed. Feed intake, egg production, egg mass and feed conversion ratio were influenced by Ile: Lys ratios quadratically. The egg weight was not affected by Ile: Lys ratio. No differences were observed in the egg quality according to Ile: Lys ratios. The data indicates that the optimum digestible isoleucine: digestible lysine ratio for laying hens aged 24-40 week is 0.84:1, corresponding to the consumption of 681 mg of isoleucine and 811 mg of lysine/hen day-1.

Determination of digestible isoleucine: lysine ratio in diets for laying hens aged 42-58 weeks

Two hundred and fifty-two Hy-Line W36 laying hens were allotted in a completely randomized design with 6 treatments, 7 replicates and 6 hens per experimental unit in order to determine the ideal ratio of isoleucine (Ile) in relation to lysine (Lys) to laying hens aged 42-58 weeks. Experimental diets contained digestible Ile at different levels, resulting in different Ile:Lys ratios (0.73:1; 0.78:1; 0.83:1; 0.88:1; 0.93:1 and 0.98:1). A basal diet was formulated to provide Isoleucine in levels below recommendations. This diet was supplemented with L-isoleucine to make up the 6 diets. Each diet was made isonitrogenous by varying the dietary contents of glutamic acid and isocaloric by adjusting the contents of cornstarch. All essential amino acids were provided proportionally to lysine. Egg production, egg weight, egg mass, feed conversion ratio, albumen, yolk and eggshell contents were recorded and compiled at every 28-day period. No differences were observed in the performance over a wide range of dietary isoleucine concentrations from 5.76 to 7.73 g/kg corresponding to 0.73:1 to 0.98:1 Ile:Lys ratios. The lowest Ile:Lys ratio (0.73:1) was sufficient to ensure satisfactory performance of birds, corresponding to the consumption of 534 mg of isoleucine and 731 mg of lysine/day.