Mechanical and Ultrastructural Properties of Eggshell in Two Egyptian Native Breeds of Chicken

The effects of using UV light instead of formaldehyde in disinfection of hatching eggs on shell microbial load, embryo development, hatchability, and chick characteristics

In this study, it was aimed to determine the effects of using UV light instead of formaldehyde in disinfection of hatching eggs on the microbial load, shell and yolk compositions, embryo development, hatching results and chick characteristics. 552 hatching eggs were divided into formaldehyde fumigation and disinfection with UV groups. After disinfection, bacteriological growth was not observed in groups. While the difference between the groups in terms of hatching results was insignificant, it was determined that the incubation period in the UV group was shorter than that of formaldehyde group. On the hatching day, relative chick weight and weight of bursa Fabricus were found to be higher in the UV group  . UV light can be used as an alternative to formaldehyde as disinfection of hatching eggs because it is easy to use and does not cause any negative effects on egg shell structure, embryo development, hatching results and chick characteristics.

The Impact of Phytase and Different Levels of Supplemental Amino Acid Complexed Minerals in Diets of Older Laying Hens

A study was conducted to evaluate the effects of different sources and levels of supplemental amino acid-complexed minerals (AACM), with and without enzyme phytase (EZ). A total of 512 Dekalb White laying hens at 67 weeks of age were used in a 2 × 3 + 2 factorial arrangement of 8 treatments and 8 replications each. The main effects included EZ supplementation (600 FTU kg-1) and AACM inclusion level (100%, 70%, and 40% of inorganic mineral recommendations), plus two control treatments. The group of hens fed AACM-100 showed lower feed intake than the inorganic mineral (IM) group. The diet containing AACM-EZ-70 provided a higher (p < 0.05) laying percentage and a lower (p < 0.05) feed conversion ratio than both the IM and IM-EZ diets. The groups fed AACM-EZ-40, AACM-EZ-100, and AACM-70 produced heavier yolks (p < 0.05). Hens fed IM laid eggs with the lowest yolk and albumen weights (p < 0.05). Layers fed with AACM-100 and AACM-70 produced the most resistant eggshells to breakage (p < 0.05). In diets containing phytase, the optimal AACM recommendations for better performance and egg quality in older laying hens are: 42, 49, 5.6, 28, 0.175, and 0.70 mg kg-1 for Zn, Mn, Cu, Fe, Se, and I, respectively.

Dietary L-glutamine affects eggshell quality in the post-peak laying period

In the current study the hypothesis that 1.0% dietary inclusion of glutamine (Gln), a conditionally essential amino acid that influences protein synthesis and shows anti-osteoporotic effect, can influence eggshell quality was tested on laying hens in the post-peak laying period. A 30-week-old Bovans Brown hens were randomly assigned to control group or group supplemented with Gln in the form of alpha-ketoglutarate (10 g/kg) with 12 replicate cages (2 hens/cage) in each group. The experimental period lasted for 30 weeks, from the 31st to the 60th week of age of hens, when eggs were collected and selected eggshell quality indices were determined. While Gln supplementation had no effect on egg geometry and eggshell cracking force, the analysis of eggshell quality showed an increase of the eggshell thickness (P<0.01), porosity (P<0.01), eggshell specific surface (P<0.001) and positive changes in other mechanical parameters (decrease of eggshell stiffness and Young’s modulus, P<0.05 and P<0.01, respectively; increase of work needed to crack the eggshell, P<0.05). Changes in eggshell mineral composition, including an increase of Ca content (P<0.001), were also observed. In conclusion, the current study showed a beneficial effect of Gln on the eggshell thickness, calcification, and some mechanical parameters.

Dietary zinc supplementation affects eggshell quality and ultrastructure in commercial laying ducks by influencing calcium metabolism

This study evaluated dietary Zn supplementation on productive performance, eggshell quality and ultrastructure, and calcium metabolism during eggshell formation in laying ducks. A total of 360 Longyan laying ducks (45-wk) were randomly divided into 5 treatment groups with 6 replicates of 12 birds each and fed for 20 wk. The 6 treatments fed the basal diet supplemented with 0 (control), 20, 40, 80, or 160 mg Zn/kg (ZnSO4·H2O). Dietary supplemental level at 80 mg/kg increased egg production (4.3%) and mass (5.7%), and decreased FCR (2.9%) compared to the basal diet, and these indices increased quadratically with increasing Zn supplemental levels (P < 0.05). The shell breaking strength (15.8%) and fracture toughness (10.6%) were higher with the supplementation of Zn at 80 mg/kg than the basal diet, and increased quadratically with Zn supplementation (P < 0.05). Dietary supplementation of Zn at 80 mg/kg improved shell ultrastructure by increasing total (9.0%) and effective thickness (14.2%) and decreasing mammillary thickness (12.0%), and their responses were quadratic with increasing Zn levels (P < 0.05). The supplementation of Zn affected the calcium contents in plasma, tibias and ulna, ulna phosphorus content, and linear and quadratic effects were observed, and higher values were observed with 160 mg/kg Zn supplementation than control (P < 0.05). The supplemental Zn level at 80 mg/kg increased shell effective thickness in growth stage (P < 0.05), and shell calcium and phosphorus content in initial and growth stages (P < 0.05). Dietary Zn supplementation did not affect the gene expression of Ca2+ transporters in the eggshell gland, but affected the expression of HCO3- exchanger in initial and growth stage (P < 0.05). Overall, dietary Zn supplementation could improve productive performance and shell quality in laying ducks at late phase of production, and calcium metabolism and deposition were modulated by Zn influencing HCO3- secretion and thus affecting shell ultrastructure and quality. A supplemental level of 80 mg/kg Zn in the diet with a basal content of 34.0 mg/kg was optimal, and higher level (160 mg/kg) decreased shell calcium deposition by depressing its metabolism.

Dietary chloride levels affect performance and eggshell quality of laying hens by substitution of sodium sulfate for sodium chloride

The objective of this study was to evaluate the effect of dietary chloride (Cl) levels on performance, eggshell mechanical quality, and ultrastructure in layers based on the substitution of sodium chloride (NaCl) by sodium sulfate (Na₂SO₄). Three hundred sixty Jing Brown laying hens aged 43 wk were randomly divided into 5 groups and fed with corn–soybean meal diets containing 0.06, 0.10, 0.15, 0.20, and 0.25% total Cl inclusion. Every group had 8 replicates of 9 birds each. The feeding trial lasted for 12 wk. The results showed dietary 0.06% Cl due to complete substitution of NaCl by Na₂SO₄, depressed performance (P < 0.05) from 45 to 54 wk of age, increased serum creatinine level (P < 0.05), and caused visible renal tubular atrophy. Dietary Cl levels quadratically affected breaking strength, thickness, and weight of eggshell (P < 0.05). Better eggshell quality could be obtained when NaCl was partly replaced by Na₂SO₄ in laying hen diets maintaining Cl level at 0.10 or 0.15%. Moreover, the eggshell ash content was affected by Cl levels in a quadratic (P < 0.001) manner, with higher values observed in the 0.10 and 0.15% Cl groups (P < 0.05). Besides, the eggshell ultrastructural data showed that the total thickness and effective thickness significantly increased (P < 0.05) and mammillary thickness decreased (P < 0.05) in the group of dietary 0.15% Cl compared with the groups of 0.06 and 0.25% Cl. In conclusion, the complete substitution of dietary NaCl by Na₂SO₄ may induce Cl deficiency and depress laying performance and eggshell quality. Na₂SO₄ could partly replace NaCl in diets for laying hens (43–54 wk of age) without adverse effects on performance at the dietary Cl level from 0.10 to 0.25%. Better eggshell quality could be obtained when NaCl was partly replaced by Na₂SO₄ in laying hen diets maintaining Cl level at ∼0.15%.

Filho C. Efeito de diferentes aditivos zootécnicos sobre a qualidade de ovos em duas fases produtivas da codorna

RESUMO Com o objetivo de avaliar a qualidade dos ovos de codornas alimentadas com diferentes aditivos em duas fases de produção, 360 codornas foram distribuídas em um delineamento inteiramente ao acaso, em esquema de parcela subdividida no tempo (de nove até 23 e de 24 até 39 semanas de idade), com cinco tratamentos e oito repetições de nove aves cada, organizados da seguinte forma: controle, antibiótico, prebiótico, probiótico e simbiótico. As variáveis analisadas foram: unidade Haugh, índice de gema, porcentagem dos componentes do ovo, espessura de casca medida pelo micrômetro e pelo MEV. O fornecimento dos aditivos no segundo período aumentou a unidade Haugh e nos dois períodos avaliados proporcionou aumento da porcentagem de gema e de casca e da espessura da casca e de suas membranas. A inclusão dos aditivos foi mais eficiente em aumentar o peso dos ovos e a porcentagem de gema e de casca no segundo período. A espessura da casca (MEV) melhorou após inclusão de antibiótico e simbiótico na ração no segundo período. A inclusão de aditivos na ração melhora a qualidade dos ovos de codornas durante toda a fase produtiva. Antibiótico e simbiótico são mais eficazes em melhorar a espessura da casca dos ovos produzidos durante o segundo período produtivo.

Interrelationships between Morphological, Densitometric and Mechanical Properties of Eggs in Japanese Quails (Coturnix Japonica)

Eggshell quality in birds results from mineral density and composition determining its mechanical endurance. The aim of the study was to determine interrelationships between morphological, densitometric and mechanical properties of eggs in Japanese quails. Twenty four eggs randomly collected from 17-week-old quails were subjected to morphological, denstiometric and mechanical evaluation using dual-energy X-ray absorptiometry (DEXA), quantitative computed tomography (QCT) and three-point bending test. Weight, height and width of eggs were positively correlated with the densitometric parameters obtained using DEXA (egg mineral density (EMD) and egg mineral content (EMC)) and QCT (total egg volume (TEvol) and total eggshell volume (TESvol)). Positive correlations were stated between TEvol and TESvol (r=0.52; P<0.05) and EMD and EMC r=0.83; P<0.05). Egg mineral density revealed positive correlations with TEvol and mean volumetric eggshell mineral density (MvESMD), while EMC was positively correlated with TEvol, TESvol and MvESMD (all P<0.05). Eggshell breaking strength was positively correlated with MvESMD (r=0.53; P<0.05) and negatively correlated with eggshell thickness (r=−0.50; P<0.05). In conclusion, the results obtained in this study showed numerous interrelationships between morphological, densitometric and mechanical properties of eggs in Japanese quails. Both DEXA and QCT were shown to be valuable tools for evaluation of whole egg and eggshell quality with superior prognostic value of QCT for eggshell mechanical endurance prediction. The elaborated experimental model may serve for further investigations on physiological, pharmacological, environmental, nutritional and toxicological factors influencing egg quality.

Eggshell quality: a comparison between Fayoumi, Gimieizah and Brown Hy-Line strains for mechanical properties and ultrastructure of their eggshells

This experiment was designed to study the relationship between mechanical properties and ultrastructure of three genetic groups (Fayoumi, Gimieizah and Brown Hy-Line strains). To assess eggshell mechanical parameters a total of 120 eggs from each strain was used. This study suggested predicting the mechanical properties and ultrastructure of eggshells when egg weight was equal for the three strains (39.8 g). There was a significant difference among strains for shell thickness, eggshell breaking strength and stiffness, with the Fayoumi eggshells recording the highest values compared with other strains. The palisade layer of Gimieizah and Brown Hy-Line eggshells was thinner than that of Fayoumi eggshells. There were significant correlations between palisade length and breaking strength (0.51), shell thickness (0.89) and stiffness (0.48); however, the length of the palisade layer was significantly negatively correlated with elasticity (–0.85). The Fayoumi (local Egyptian strain) showed higher resistance for eggshell breakage than the Hy-Line commercial strain due to their longer palisade layer noting that there were no significant differences in egg weight between the two. The length of the palisade layer plays an important role in eggshell strength, so it is of interest to include these parameters in selection programs aimed to improve eggshell strength. However, a negative correlation between length of palisade layer and elasticity prevented improvement of these two parameters.