Organic trace minerals improve eggshell quality by improving the eggshell ultrastructure of laying hens during the late laying period

Dietary sodium sulfate supplementation improves eggshell quality, uterine ion transportation and glycosaminoglycan synthesis in laying hens

OBJECTIVE

This study evaluated the effects of dietary sodium sulfate (Na2SO4) supplementation on eggshell quality, uterine ion transportation, and glycosaminoglycan (GAG) synthesis.

METHODS

A total of 432 48-wk-old Hy-line Brown laying hens were randomly divided into 6 dietary treatments with 8 replicates of 9 birds each. The experimental laying hens were fed the corn-soybean meal diets (containing 0.15% NaCl) supplemented with 0.22%, 0.37%, 0.52%, 0.68%, 0.83%, or 0.99% Na2SO4 for 12 weeks.

RESULTS

Results showed that the eggshell breaking strength and eggshell ratio significantly increased in the 0.68% Na2SO4 group at the end of wk 56 and wk 60 (p<0.05). In addition, eggshell thickness and weight significantly increased in the 0.68% Na2SO4 group at the end of wk 60 (p<0.05). Eggshell calcium content in the 0.68% Na2SO4 group was higher than that of 0.22% and 0.99% groups (p<0.001). The concentrations of K+ and Ca2+ in the uterine fluid were significantly greater in the 0.68% group than in the other groups (p<0.05). Dietary Na2SO4 increased the gene expression of SLC8A1, SCNN1A, ATP1B1, and KCNMA1 quadratically in the uterus (p<0.05), and higher values were observed in 0.68% group. Additionally, the GAG contents of the eggshell, and ATP-sulfurylase, sulfotransferase, chondroitin sulfate, and dermatan sulfate contents of the isthmus increased linearly with the increment of dietary Na2SO4 (p<0.05). There was a remarkable reduction in mammillary knob width, mammillary thickness, and the percentage of the mammillary layer (p<0.05), and an increment in mammillary knob density, effective thickness, and total thickness in the 0.68% group compared with the 0.22% and 0.99% groups (p<0.05).

CONCLUSION

Overall, there was no dose-related difference with the increment of dietary Na2SO4 levels. The addition of 0.68% Na2SO4 in the corn-soybean basal diet (0.15% Cl) regulated uterine ion transport, increased GAG contents of eggshell, and improved eggshell ultrastructure and quality.

Probiotics improve eggshell quality via regulating microbial composition in the uterine and cecum

Probiotics benefit the health and production performance of chickens, but their impact on egg and eggshell quality, particularly in the later stage, remains unclear. Here, 1-day-old Tianfu green shell-laying hens were fed either non-probiotics feed (n = 180) or feed supplemented with 100 mg / kg probiotics (n = 180). 16S rDNA sequencing indicated that dietary probiotics decreased the distribution of uterine p_Firmicutes, g_Fusobacterium, and s_Fusobacterium_unclassified, while increased p_Proteobacteria, g_Ralstonia, and s_Ralstonia_unclassified. PICRUSt2 and Bug Base analysis revealed enrichment in fatty acid metabolism, thiamine metabolism, vitamin B6 metabolism pathways and increased relative abundance of Proteobacteria, Firmicutes, Bacteroidetes. With LDA > 4.5, 35 and 25 marker bacterial taxa were identified in the uterus and cecum, respectively. Probiotics significantly increased uterine villi length and width, and the expressions of ATP2B2,SLC26A9,TF,OC-17,OCX-32, and OVAL in the uterus at the early and peak laying stage. Meantime, probiotics improved egg quality, pore density of eggshell barrier layer, and levels of Ca2+, Na+, and Mg2+, whereas dropped levels of P3-, S2- and K+ in eggshell. In serum, Ca2+, K+, Na+ had a response to dietary probiotics at different laying stages, except Cl-. Furthermore, the changes of these phenotypes are closely related to the microbial structure of the uterus and cecum. Overall, the data suggest that dietary probiotics improved uterine and cecal microbiota, optimized egg quality, eggshell quality, uterus development, and regulated mineralization gene expression and ion content in serum and eggshell, thereby improving productivity of laying hens. These results provide reference for the application of probiotics in the laying industry.

Efficacy of dietary supplementation with 1α-hydroxycholecalciferol on performance, eggshell quality, serum metabolites, jejunal morphology and bone characteristics of laying hens at the late stage of production

The present study evaluated the effects of 1α-hydroxycholecalciferol (1αOHD3) supplementation on performance, egg quality, gut morphology, serum metabolites, and bone characteristics of Lohman LSL-Lite laying hens. A total of 180 birds (110 weeks of age) were allocated according to a completely randomized design with five treatments. Each treatment had six replicates containing six hens each. The treatments consisted of basal diet with 2000 IU/kg vitamin D3, basal diet supplemented with 1.5, 3, 4.5, and 6 μg/kg of 1αOHD3. Results showed that dietary supplementation with 1αOHD3 increased the egg production (linear P = 0.002 and quadratic P = 0.009) and gross revenue (linear P = 0.042) whilst it decreased the abnormal eggs (linear P = 0.004 and quadratic P = 0.009) in aged laying hens. Similarly, it linearly and quadratically increased the shell thickness and eggshell strength (P < 0.001). Egg mass (linear P = 0.075) showed a tendency to increase with increasing dietary 1αOHD3 supplementation levels. The egg quality parameters, including Haugh unit, relative weight of albumen, yolk and eggshell were not affected by the treatments (P > 0.05). Furthermore, 1αOHD3 supplementation increased the serum levels of calcium (linear P = 0.003 and quadratic P = 0.011), albumin (linear P = 0.016 and quadratic P = 0.033), vitamin D (linear and quadratic P < 0.001), alanine aminotransferase activity (linear P = 0.02) whilst the addition of 1αOHD3 decreased alkaline phosphatase activity (linear P = 0.003 and quadratic P = 0.011), without affecting the serum levels of phosphorus and aspartate aminotransferase activity (P > 0.05) in laying hens. In addition, the linear tendency to increase was observed (linear P = 0.062) in total protein. Dietary supplementation of 1αOHD3 increased the tibia diameter (linear P = 0.053), tibia calcium (linear P = 0.004 and quadratic P = 0.014) and tibia strength (linear and quadratic P < 0.001). The addition of 1αOHD3 did not affect the phosphorus and ash of the tibia (P > 0.05). Linear and quadratic responses were found for crypt depth (linear and quadratic P = 0.001) and villus height to crypt depth ratio (linear P = 0.004 and quadratic P = 0.010). The experimental treatments did not affect the jejunal villus height, villus width and villus surface area in aged laying hens (P > 0.05). Our findings suggest that the inclusion of 1αOHD3 is beneficial, as it enhances egg production, profitability, eggshell thickness, and tibia quality while reducing the incidence of abnormal eggs during the later phase of egg production.

Trace Minerals in Laying Hen Diets and Their Effects on Egg Quality

With the advancement in the egg industry sector, egg quality has assumed great significance in certain countries. Enhancements in the nutritional value of eggs may have direct affirmative consequences for daily nutrient intake and therefore for human health. Thus, affirmative improvement in egg quality boosts consumer preferences for eggs. Also, the improvement in eggshell quality can avoid the disposal of broken eggs and consequently economic losses. Therefore, poultry nutrition and mineral supplements have a significant impact on egg quality. Minerals are crucial in poultry feed for a number of biological processes, including catalytic, physiologic, and structural processes. For instance, they contribute to the biological processes necessary for forming and developing eggshells. To produce high-quality eggs for sale, diets must therefore contain the right amount of minerals. This review aims to highlight the role of both organic and inorganic minerals in improving egg quality, in addition to reviewing the interactions of mineral supplements with intestinal microbiota and subsequent effects on the egg quality.

Calcium deposition in chicken eggshells: role of host genetics and gut microbiota

Eggshell is predominantly composed of calcium carbonate, making up about 95% of its composition. Eggshell quality is closely related to the amount of calcium deposition in the shell, which requires chickens to maintain a robust state of calcium metabolism. In this study, we introduced a novel parameter, Total Eggshell Weight (TESW), which measures the total weight of eggshells produced by chickens over a period of 10 consecutive d, providing valuable information on the intensity of calcium metabolism in chickens. Genome-wide association study (GWAS) was conducted to explore the genetic determinants of eggshell calcification in a population of 570 Rhode Island Red laying hens at 90 wk of age. This study revealed a significant association between a specific SNP (rs14249431) and TESW. Additionally, using random forest modeling and 2-tailed testing, we identified 3 genera, Lactobacillus in the jejunum, Lactobacillus, and Fournierella in the cecum, that exhibited a significant association with TESW. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis of claudin-1 and occludin genes in individuals with low TESW and high abundance of jejunal Lactobacillus confirmed that the inhibitory effect of jejunal Lactobacillus on calcium uptake was achieved through the up-regulation of tight junctions in intestinal epithelial cells. Notably, both host and microbial factors influence TESW, displaying a mutually influential relationship between them. The microbiome-wide Genome-Wide Association Study (mb-GWAS) identified significant associations between these 3 genera and specific genomic variants, such as rs316115020 and rs316420452 on chromosome 5, rs313198529 on chromosome 11, linked to Lactobacillus in the cecum. Moreover, rs312552529 on chromosome 1 exhibited potential association with Fournierella in the cecum. This study highlights the influence of host genetics and gut microbiota on calcium deposition in eggshells during the late laying phase, providing a foundational reference for studying calcium metabolism in hens.

Organic Trace Elements Improve the Eggshell Quality via Eggshell Formation Regulation during the Late Phase of the Laying Cycle

The quality of eggshells is critical to the egg production industry. The addition of trace elements has been shown to be involved in eggshell formation. Organic trace elements have been found to have higher biological availability than inorganic trace elements. However, the effects of organic trace elements additive doses on eggshell quality during the laying period of commercial laying hens required further investigation. This experiment aims to explore the potential mechanisms of different doses of organic trace elements replacing inorganic elements to remodel the eggshell quality of egg-laying hens during the laying period. A total of 360 healthy hens (Lohmann Pink, 45-week-old) were randomly divided into four treatments, with six replications per treatment and 15 birds per replication. The dietary treatments included a basal diet supplemented with inorganic iron, copper, zinc and manganese at commercial levels (CON), a basal diet supplemented with organic iron, copper, zinc and manganese at 20% commercial levels (LOT), a basal diet supplemented with organic iron, copper, zinc and manganese at 30% commercial levels (MOT), and a basal diet supplemented with organic iron, copper, zinc and manganese at 40% commercial levels (HOT). The trial lasted for 8 weeks. The results of the experiment showed that the replacement of organic trace elements did not significantly affect the production performance of laying hens (p > 0.05). Compared with inorganic trace elements, the MOT and HOT groups improved the structure of the eggshells, enhanced the hardness and thickness of the eggshells, increased the Haugh unit of the eggs, reduced the proportion of the mammillary layer in the eggshell, and increased the proportion of the palisade layer (p < 0.05). In addition, the MOT and HOT groups also increased the enzyme activity related to carbonate transport in the blood, the expression of uterine shell gland-related genes (CA2, OC116, and OCX32), and the calcium and phosphorus content in the eggshells (p < 0.05). We also found that the MOT group effectively reduced element discharge in the feces and enhanced the transportation of iron (p < 0.05). In conclusion, dietary supplementation with 30-40% organic micronutrients were able to improve eggshell quality in aged laying hens by modulating the activity of serum carbonate transport-related enzymes and the expression of eggshell deposition-related genes.

Genetic patterns and genome-wide association analysis of eggshell quality traits of egg-type chicken across an extended laying period

The industry of egg-type chicken has shown a trend of extending the rearing period, with the goal of breeding chicken breeds capable of producing 500 qualified eggs by 700 d of age. However, the rapid decline in eggshell quality during the late laying period is one of the major challenges. In this study, a total of 3,261 Rhode Island Red chickens were used to measure eggshell quality traits including eggshell strength (ESS), eggshell thickness (EST), eggshell color (ESC) and eggshell gloss (ESG) at seven age points ranging from 36 to 90 wk of age. Phenotypic variations increased with the aging process, especially during the late laying period (> 55 wk), and the heritability during this period decreased by 22.7 to 81.4% compared to the initial and peak laying periods. Then we performed genome-wide association study (GWAS) to identify the genomic variants that associated with eggshell quality, with a custom Illumina 50K BeadChip, named PhenoixChip-I. The results indicated that 2 genomic regions on GGA1(23.24-25.15Mb; 175.95-176.05 Mb) were significantly (P < 4.48E-06) or suggestively (P < 8.97E-05) associated with ESS, which can explain 9.59% and 0.48% of the phenotypic variations of ESS46 and ESS36, respectively. Three genes, FRY, PCNX2, and ENSGALG00000052468, were considered to be the candidate genes for ESS. For other traits, the genome-wide suggestive SNPs were identified at each age point, exhibiting a certain trend with aging process. Additionally, SNP enrichment analysis and functional annotation of cross-tissue regulatory elements to ESS36 revealed a high concentration of enhancer elements specific to shell gland and kidney tissues. This study, deepened our knowledge of eggshells and laying a valued scientific foundation for chicken molecular breeding.

Effects of housing systems and laying phases on external and internal egg quality characteristics of indigenous guinea fowl hens

The study investigated the effect of housing system and laying phases on the internal and external qualities of guinea fowl eggs laid in three different housing systems. The trial involved the use of 117, 34-wk-old guinea fowl hens which were assigned to three housing types, which were battery cages, deep litter, and deep litter housing systems with free runs, which had the same dimensions as deep litter houses but with free run and open-air space to allow the birds to have free access to soil and exhibit natural behavior. The laying phases of the birds were partitioned into three (36 to 40, 41 to 45, and 46 to 50 wk of age). The data collected were subjected to analysis of variance (ANOVA) using a 2 × 3 factorial design. The findings demonstrated that both housing type and laying period significantly influenced egg quality parameters, with deep litter housing exhibiting higher egg weight, egg breadth, and shell surface area. Battery cage housing had thicker shells and a higher percentage of shell weight than total egg weight. As the birds aged, most parameters increased, while shell thickness decreased. The interaction between housing type and laying period played a crucial role, with egg weight, breadth, and egg shape index increasing as the birds aged. The shell thickness decreased as the laying period progressed across all housing systems. During the 40 to 45 wk period of lay, they exhibited the highest albumen height, haugh unit, and % yolk weight. The study's findings highlight how the interaction between the housing system and the laying period impacted the internal quality of guinea fowl eggs.

Genome-Assisted Probiotic Characterization and Application of Lactiplantibacillus plantarum 18 as a Candidate Probiotic for Laying Hen Production

Probiotics gained significant attention for their potential to improve gut health and enhance productivity in animals, including poultry. This comprehensive study focused on the genetic analysis of Lactiplantibacillus plantarum 18 (LP18) to understand its survival and colonization characteristics in the gastrointestinal tract. LP18 was supplemented in the late-stage diet of laying hens to investigate its impact on growth performance, egg quality, and lipid metabolism. The complete genome sequence of LP18 was determined, consisting of 3,275,044 base pairs with a GC content of 44.42% and two circular plasmids. Genomic analysis revealed genes associated with adaptability, adhesion, and gastrointestinal safety. LP18 supplementation significantly improved the daily laying rate (p < 0.05) during the late-production phase and showed noteworthy advancements in egg quality, including egg shape index (p < 0.05), egg albumen height (p < 0.01), Haugh unit (p < 0.01), and eggshell strength (p < 0.05), with notable improvements in eggshell ultrastructure. Additionally, LP18 supplementation resulted in a significant reduction in serum lipid content, including LDL (p < 0.01), FFA (p < 0.05), and Gly (p < 0.05). These findings provide valuable insights into the genomic characteristics of LP18 and the genes that support its survival and colonization in the gastrointestinal tract. Importantly, this study highlights the potential of LP18 as a probiotic candidate to enhance productivity, optimize egg quality, and modulate lipid metabolism in poultry production.

Effect of Dietary Casein Phosphopeptide Addition on the Egg Production Performance, Egg Quality, and Eggshell Ultrastructure of Late Laying Hens

(1) Objective: This study aimed to assess the effects of dietary casein phosphopeptide (CPP) supplementation on the egg production performance of late laying hens and the resulting egg quality and eggshell ultrastructure. (2) Methods: A total of 800 laying hens aged 58 weeks were randomly assigned into 5 groups with 8 replicates of 20 hens each. The hens were fed a basal diet supplemented with 0 (control, T1), 0.5 (T2), 1.0 (T3), 1.5 (T4), and 2.0 (T5) g/kg CPP for 9 weeks. (3) Results: Dietary CPP supplementation was found to be beneficial for improving eggshell quality. The spoiled egg rate of the experimental groups was lower than that of the control group (linear and quadratic effect, p < 0.05). The yolk color in the T2, T3, and T4 groups was higher than that in the T1 group (quadratic effect, p < 0.05). The shell thickness in the T4 group was higher than that in the T1 and T2 groups (linear effect, p < 0.05). The shell color in the experimental groups was higher than that in the control group (linear and quadratic effect, p < 0.05). The effective thickness in the T3-T5 groups (linear and quadratic, p < 0.05) and the number of papillary nodes in the T2 and T3 groups were higher than those in the T1 group (quadratic, p < 0.05). The calcium content in the T2 and T3 groups was higher than that in the T1 group (quadratic effect, p < 0.05). The iron content in the T2 and T3 groups was higher than that in the T1 group (p < 0.05). (4) Conclusion: In summary, 0.5-1.0 g/kg CPP supplementation reduced the spoiled egg rate, enhanced the yolk and eggshell colors, increased the thickness of the effective layer, and the calcium and iron contents in the eggshell.

Effects of Dietary Rare Earth Chitosan Chelate on Performance, Egg Quality, Immune and Antioxidant Capacity, and Intestinal Digestive Enzyme Activity of Laying Hens

Rare earth chitosan chelate salt (RECC) is a potential feed additive and is a product of the chelation effect between rare earth ions and chitosan. This research study aims to explore the effects of dietary RECC on performance, egg quality, intestinal digestive function, and the immune and antioxidant capacity of laying hens in the late phase of production. A total of 360 56-week-old Dawu Jinfeng laying hens were randomly allotted into four treatment groups with six replicates per treatment and 15 birds per replicate. The laying hens were fed the basal diet supplemented with, respectively, 0 (control: CON), 100 (R1), 200 (R2), and 400 (R3) mg/kg for 8 weeks. Dietary RECC significantly improved average daily feed intake (ADFI) and average daily egg yield in both linear and quadratic manner (p < 0.05). In addition, albumen height and HU were improved significantly (p < 0.05) in a dose-dependent manner of RECC. In addition, a significant decrease (p < 0.05) in serum TP, IgA, and MDA for the R1 group and IgG in the R2 group were notable, while the increase in serum TP and decrease in T-AOC were found for R3 dietary group compared to CON (p < 0.05). The level of intestinal IL-2 and TNF-α was decreased by dietary RECC (p < 0.01). The activities of the digestive enzyme (α-Amylase, lipase, and Trypsin) showed a quadratic change with an increase and then decrease in response to increasing dose of RECC, 200 mg/kg RECC significantly increased the activity of lipase and Trypsin (p < 0.01). Supplementation of dietary RECC at low doses compared to higher doses impacted positive effects on the antioxidant capacity and immune function (p < 0.05). The utilization of RECC as a feed additive in the diet of aged laying hens exerted beneficial effects on egg production, albumen quality, humoral immunity, inflammatory response, and activity of digestive enzymes. Thus, the regulation of antioxidant capacity and duodenal function via increased enzyme activity and immune and inflammatory response were critical to the improvement of laying performance and egg quality in aged hens. The optimal supplemental dose is 100-200 mg/kg.

Effects of trace minerals source in the broiler breeder diet and eggshell translucency on embryonic development of the offspring

In 2 experiments, interactions between trace mineral (Zn, Mn, Cu, Se) source (organic or inorganic) in the broiler breeder diet and egg translucency (high or low) on egg characteristics and embryonic development were investigated. In the first experiment, eggs from old breeders (55-57 wk) and in the second experiment, eggs from prime breeders (34-36 wk) were used. Egg composition and bacterial load on the eggshell were analyzed in fresh eggs. During incubation, metabolic heat production of the embryos (d 8 (E8) to 19 of incubation) and tibia ossification (E8.5-E14.5) were determined daily. At hatch, chicken quality was assessed, including tibia biophysical characteristic. Egg quality was not affected by breeder trace minerals source or egg translucency in both experiments. In both experiments, an interaction between trace minerals source and translucency score was found for egg weight loss during incubation. In inorganic trace minerals fed breeders, a high egg translucency resulted in a higher egg weight loss than a low egg translucency, whereas this difference was not seen in organic trace minerals fed breeders. Embryonic heat production and tibia ossification were not affected by trace minerals source or egg translucency. Chicken quality showed ambiguous results between experiment 1 and 2 regarding trace minerals source in the breeder diet. In experiment 2, high translucent eggs from organic fed breeders hatched later than eggs from the other three treatment groups and additionally, high egg translucency resulted in lower residual yolk weight and higher heart and liver percentage of YFBM compared to low egg translucency. Tibia biophysical characteristics at hatch were not affected by trace minerals source or egg translucency. It can be concluded that organic trace minerals source in broiler breeder diet affects eggshell conductance, particularly in low translucent eggs, but effects on chicken quality and tibia characteristics appears to be limited.

Effects of supplementation of inorganic trace elements with organic trace elements chelated with hydroxy methionine on laying performance, egg quality, blood micronutrients, antioxidant capacity and immune function of laying ducks

Introduction

This study aimed to investigate the effects of organic trace elements chelated with hydroxy methionine (OTE-HM) in diets, which substituted inorganic trace elements, on laying performance, egg quality, blood microelement content, antioxidant capacity and immune function of laying ducks.

Methods

A total of 300 healthy laying ducks at age of 30 wk were randomly divided into 5 treatments and 10 ducks per replicate. The treatments included a control group (CON) which was served with basal diet supplemented with 20 mg/kg Cu, 50 mg/kg Fe, 70 mg/kg Mn, and 70 mg/kg Zn in inorganic form, and 4 OTE-HM treated groups (OTE-HM25, OTE-HM50, OTE-HM75, OTE-HM100) which were served with basal diets supplemented with OTE-HM providing trace elements (combination of Cu, Fe, Mn, Zn) at 25%, 50%, 75% and 100% of the commercial levels, respectively.

Results

Results showed that substitution of inorganic trace elements with OTE-HM did not affect egg production, qualified egg rate, average egg weight, average daily egg mass, average daily feed intake, or feed per kg egg of laying ducks (P &gt; 0.05). Dietary with OTE-HM did not influence eggshell strength, eggshell thickness, egg shape index, eggshell ratio, yolk ratio, albumen ratio, albumen height, and Haugh unit of the sampled eggs of ducks (P &gt; 0.05), but increased the yolk color, compared with dietary with inorganic trace elements (P&lt; 0.01). Moreover, the blood content of Cu of the laying ducks was significantly increased by OTE-HM compared with that in CON (P&lt; 0.001), but the other elements in laying duck blood were not different among treatments (P &gt; 0.05). OTE-HM (75% and 100%) significantly increased serum activities of glutathione peroxidase and Cu-Zn superoxide dismutase, and decreased serum content of malonaldehyde of laying ducks compared with those in CON (P&lt; 0.05). OTE-HM (50%, 75%, and 100%) significantly increased the serum contents of immunoglobulin G and immunoglobulin A of laying ducks compared with those in CON (P&lt; 0.05).

Discussion

Collectively, replacing inorganic trace elements with 50% and 75% OTE-HM in diets did not influence the laying performance or egg quality, but improved trace element efficacy, antioxidant capacity and immune function of the laying ducks.

A Comparison between Vitamin D3 and 25-Hydroxyvitamin D3 on Laying Performance, Eggshell Quality and Ultrastructure, and Plasma Calcium Levels in Late Period Laying Hens

The objective of this study was to compare high supplementary doses (125 µg/kg) of vitamin D3 (VD3) or 25-hydroxyvitamin D3 (25-OHD3) with commercial supplementary doses (62.5 µg/kg) of VD3 on laying performance, eggshell quality and ultrastructure, and plasma calcium levels in late period laying hens. A total of 1512 Roman Gray (60-week-old) laying hens were allotted into three treatments with 12 replicates and 42 birds in each replicate. During the 12-week trial period, the layers were fed a basal diet supplemented with different doses of VD3 or 25-OHD3 (62.5 µg/kg VD3 in control group, CON; 125 µg/kg VD3 in high level VD3 group, VD3; 125 µg/kg 25-OHD3 in high level 25-OHD3 group, 25-OHD3). The results showed that high supplementary doses of VD3 or 25-OHD3 increased laying rate (p < 0.05). Moreover, the layers fed high doses of VD3 or 25-OHD3 diets had decreased unqualified egg rate and mortality (p < 0.05). High supplementary doses of VD3 or 25-OHD3 increased eggshell strength and eggshell thickness (p < 0.05). From observation in eggshell ultrastructure, high doses of VD3 or 25-OHD3 diets increased the palisade layer thickness and mammillary knob density (p < 0.05). Furthermore, high doses of VD3 or 25-OHD3 diets increased the calcium levels in plasma (p < 0.05). In summary, compared with 62.5 µg/kg doses of VD3, supplementary 125 µg/kg doses of VD3 or 25-OHD3 improved the laying performance, eggshell quality, and plasma calcium levels in late period laying hens. Additionally, there was an equal effect on laying performance and eggshell quality in the hens fed dietary 125 µg/kg doses of VD3 or 25-OHD3.

Transcriptomic analysis of the liver in aged laying hens with different eggshell strength

Eggshell is composed of a very ordered and mineralized structure and is important for egg quality. Eggshell strength is particularly important because of its direct association with economic outcomes and egg safety. Various factors related to laying hens and their environment affects eggshell strength. However, the molecular mechanisms of liver functions related to decreased eggshell strength of aged laying hens are largely unknown. Therefore, this study aimed to identify potential factors affecting eggshell strength in aged laying hens at the hepatic transcriptomic level. A total of five hundred 92-wk-old Hy-line Brown laying hens were screened to select those exhibiting the greatest variation in eggshell strength. Based on the final eggshell strength, 12 hens producing eggs with strong eggshell strength (SES) and weak eggshell strength (WES) were finally selected (n = 6) for liver tissue sampling. The RNA-sequencing was performed to identify differentially expressed genes (DEGs) between the 2 groups. We identified a total of 2,084 DEGs, of which 1,358 genes were upregulated and 726 genes were downregulated in the WES group compared with SES group. According to the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, the DEGs indicated the mammalian target of rapamycin signaling pathway, the Janus kinase-signal transducer and activator of transcription pathway, the mitogen‑activated protein kinase signaling pathway, and the insulin resistance pathways. Genes related to fatty liver disease were upregulated in WES group compared with SES group. In addition, expression of several genes associated with oxidative stress and bone resorption activity was altered in aged laying hens with different eggshell strength. Overall, these findings contribute to the identification of genes involved in different intensity of eggshell strength, enabling more understanding of the hepatic molecular mechanism underlying in decreased eggshell strength of aged laying hens.

Effect of Organic or Inorganic Mineral Premix in the Diet on Laying Performance of Aged Laying Hens and Eggshell Quality

In this study, we examined the effect of diets supplemented with organic and inorganic mineral premixes on the laying performance and eggshell quality of aged laying hens. A total of 600 68-week-old Hy-Line Brown laying hens were randomly assigned to 1 of 3 dietary treatments, repeated 5 times: Mash type basal diet, basal diet supplemented with an inorganic mineral premix (1.0 g/kg), and basal diet supplemented with an organic mineral premix (1.8 g/kg). The results showed that eggshell strength was higher (p < 0.01) in the inorganic mineral diet group than in the organic mineral and basal diet groups. Further, the levels of Fe and Mn in the liver were higher (p < 0.05) in the inorganic and organic mineral diet groups than in the basal diet group. The concentrations of Fe and Mg in the spleen were different (p < 0.05) among the treatment groups, with the highest levels reported in the organic mineral premix group. The concentrations of Cu, Zn, and Mn in the eggshell were different (p < 0.05) among the groups, with the highest levels reported in the inorganic and organic mineral premix diet groups. In conclusion, a diet containing organic mineral premix improved eggshell strength and had no detrimental effect on the laying performance of aged laying hens.

Dietary naringin supplementation on laying performance and antioxidant capacity of Three-Yellow breeder hens during the late laying period

In this study, the effects of 3 graded dietary levels (0.1%, 0.2%, and 0.4%) of naringin were studied in Three-Yellow breeder hens during the late laying period (55-62 wk). A total of 480 Three-Yellow breeder hens (54-wk-old) were randomly divided into 4 groups (6 replicates of 20 hens): basal diet group (C), and basal diets supplemented with 0.1%, 0.2%, and 0.4% of naringin (N1, N2, and N3), respectively. Results showed that dietary supplementation with 0.1%, 0.2%, and 0.4% of naringin for 8 wk increased the laying rate and egg mass, enhanced egg yolk color, and decreased the feed egg ratio (P < 0.05). Meanwhile, compared with hens in C group, there were more preovulatory follicles and higher ovarian index as well as an enhanced ovarian somatic cell proliferation in hens of N2 and N3 groups (P < 0.05). With 0.2% and 0.4% naringin, glutathione concentration, the activity of catalase and total superoxide dismutase, and the total antioxidant capacity of ovarian tissues and serum increased (P < 0.05), while the contents of malondialdehyde and hydrogen peroxide decreased (P < 0.05). Moreover, compared to C group, the transcription levels of antioxidant genes in ovarian tissues increased in hens from N2 and N3 groups (P < 0.05). In conclusion, supplementation with 0.2% and 0.4% naringin both could improve the laying rate, ovarian and serum antioxidant capacity of Three-Yellow breeder hens during the late laying period.

Relative Bioavailability of Trace Minerals in Production Animal Nutrition: A Review

The importance of dietary supplementation of animal feeds with trace minerals is irrefutable, with various forms of both organic and inorganic products commercially available. With advances in research techniques, and data obtained from both in-vitro and in-vivo studies in recent years, differences between inorganic and organic trace minerals have become more apparent. Furthermore, differences between specific organic mineral types can now be identified. Adhering to PRISMA guidelines for systematic reviews, we carried out an extensive literature search on previously published studies detailing performance responses to trace minerals, in addition to their corresponding relative bioavailability values. This review covers four of the main trace minerals included in feed: copper, iron, manganese and zinc, and encompasses the different types of organic and inorganic products commercially available. Their impact from environmental, economic, and nutritional perspectives are discussed, along with the biological availability of various mineral forms in production animals. Species-specific sections cover ruminants, poultry, and swine. Extensive relative bioavailability tables cover values for all trace mineral products commercially available, including those not previously reviewed in earlier studies, thereby providing a comprehensive industry reference guide. Additionally, we examine reasons for variance in reported relative bioavailability values, with an emphasis on accounting for data misinterpretation.

Effects of Zinc Methionine Hydroxy Analog Chelate on Laying Performance, Serum Hormone Levels, and Expression of Reproductive Axis Related Genes in Aged Broiler Breeders

Inorganic zinc (Zn) supplements are commonly used in poultry feeds, but their low utilization results in the increase of Zn excretion. Thus, to provide a new perspective for the substitution of inorganic Zn, a novel Zn methionine hydroxy analog chelate (Zn-MHA) was studied in the present study to evaluate its effects on laying performance, serum hormone indexes and reproductive axis-related genes in broilers breeders. A total of 480 Hubbard breeders (56-week-old) were fed a basal diet (containing 27.81 mg Zn/kg) without Zn addition for 2 weeks, and then allocated to 4 groups with 6 replicates (each replicate consisting of 10 cages and 2 breeders per cage) for 10 weeks. Four treatment diets given to broiler breeders included the basal diet added with 25, 50, and 75 mg/kg of Zn-MHA and 100 mg/kg of Zn sulfate (ZnSO₄). The laying rate, egg weight and feed conversation ratio increased in the 75 mg/kg Zn-MHA group compared to the ZnSO₄ group. The eggshell thickness was not decreased with the addition of 50 mg/kg and 75 mg/kg Zn-MHA in the diet compared to the 100 mg/kg ZnSO₄ group. There was a significant improvement in the reproductive performance of breeders in the 75 mg/kg Zn-MHA group, including the fertility and 1-day-old offspring weight. Besides, serum sex hormone levels including FSH and P₄ increased significantly in 75 mg/kg Zn-MHA group. No significant effect on the ovarian weight or the number of follicles in broiler breeders was observed by supplementing Zn-MHA. Compared to the 100 mg/kg ZnSO₄ group, dietary supplementation with 75 mg/kg of Zn-MHA showed an up-regulation of the FSHR mRNA in the granular layer of follicles. However, dietary supplementation of Zn-MHA had no effects on mRNA expressions of the ovarian LHR and PRLR genes. These findings reinforce the suggestion that Zn-MHA (75 mg/kg) could replace ZnSO₄ (100 mg/kg) as a Zn supplement in diet of broiler breeders, which resulted in better laying and reproduction performances by regulating the expression levels of reproductive axis related genes and serum hormone levels.

Low Level of Dietary Organic Trace Elements Improve the Eggshell Strength, Trace Element Utilization, and Intestinal Function in Late-Phase Laying Hens

This study was conducted to evaluate the effects of organic trace elements (Cu, Fe, Zn, and Mn) on performance, egg quality, trace elements utilization, and intestinal function in late-phase laying hens. A total of 1,080 laying hens (Hy-line brown, 65 weeks old) were randomly assigned to four treatments with six replications of 45 layers each. The basal diet was prepared without adding exogenous trace elements. The control group was fed with a basal diet supplemented with 600 mg/kg of inorganic trace elements. The three treatment groups were fed basal diets supplemented with 300, 450, and 600 mg/kg organic trace elements (OTE300, 450, and 600), respectively. The results showed that there was no significant difference in growth performance among all treatments. However, OTE450 significantly improved the eggshell strength of laying hens (p &lt; 0.05), but had no significant effects on haugh unit, egg yolk weight, eggshell weight, and eggshell thickness, compared with other groups. Moreover, compared with the control group, OTE450 significantly increased the contents of copper, iron, and zinc in serum (p &lt; 0.05). Meanwhile, all of the trace elements had a lower deposition in the feces in organic trace elements groups (p &lt; 0.05). Histological analysis showed that the addition of organic trace elements could significantly improve the villus height and villus concealment ratio (p &lt; 0.05). In addition, the messenger RNA (mRNA) and protein expressions of divalent metal transporter 1 (DMT1), zinc transporter 1 (ZnT-1), and ferroportin 1 (FPN1) were the highest in the OTE450 group. In conclusion, OTE450 could improve egg quality, intestinal function, and trace element utilization efficiency. Thus, this study provides a theoretical basis for the application of low levels of organic trace elements in laying hens.

Low levels of organic compound trace elements improve the eggshell quality, antioxidant capacity, immune function, and mineral deposition of aged laying hens

In the egg production industry, trace elements are required as additional dietary supplements to play vital roles in performance and egg quality. Compared to inorganic microelements (ITs), appropriate dose of organic trace microelements (OTs) are environmentally friendly and sufficient to satisfy the needs of hens. In order to evaluate the extent to which low-dose OTs replace whole ITs, the effects of organic copper, zinc, manganese, and iron compound on the performance, eggshell quality, antioxidant capacity, immune function, and mineral deposition of old laying hens were investigated. A total of 1 080 57-week-old Jing Hong laying hens were assigned to five groups with six replicates of 36 layers each for an 8-week experimental period. The birds were fed either a basal diet (control treatment (CT)) or the basal diet supplemented with commercial levels of inorganic trace elements (IT 100%) or the equivalent organic trace elements at 20%, 30%, and 50% of the inorganic elements (OT 20%, OT 30%, and OT 50%, respectively). Results showed that compared with those in the CT treatment, feeding hens with inorganic or organic microelement diet had significant effects on the eggshell quality, antioxidant capacity, immune function, and mineral deposition of old laying hens (P < 0.05). The eggshell strength and ratio between OT 30%, OT 50%, and IT 100% were similar at weeks 4 and 8, and the eggshell thickness of these groups was also similar at weeks 6 and 8. At week 8, the eggshell colour in OT 50% was darker than that in IT 100%. The mineral content in the eggshells of OT 50% and IT 100% significantly increased (P < 0.001), with no significant difference in effective thickness, mammillary thickness, and mammillary knob width between groups. There were no differences in the malondialdehyde content, total antioxidant capacity, and total superoxide dismutase activity in serum between OT 30%, OT 50%, and IT100%. While the catalase activities, the interleukin-1β, interleukin-10, immunoglobulin G, and immunoglobulin M concentrations in serum were not significantly different between OT 50% and IT 100%. The mineral contents in the faeces of the organic groups were considerably reduced compared with those in IT 100% (P < 0.001). In conclusion, dietary supplementation with 30-50% organic compound microelements has the potential to replace 100% inorganic microelements in the hen industry for improving eggshell quality, mineral deposition in the eggshell, antioxidant capacity, and immune function, and reducing emissions to the environment without negative effects on laying performance.

Hydroxychloride trace elements improved eggshell quality partly by modulating uterus histological structure and inflammatory cytokines expression in aged laying hens

The objectives of this study were to investigate the effectiveness of dietary zinc, copper, and manganese hydroxychloride (HC) supplementation on performance, minerals deposition, serum parameters, eggshell ultrastructure, uterus histological structure, and inflammatory cytokines in aged hens. A total of 560 Hyline Brown layers at 62 wk of age were randomly allotted into 3 groups (CON, basal diet without extra minerals supplemented; Sulphate and HC, basal diet with sulphate or hydroxychloride zinc, copper, and manganese supplementation at levels of 80, 15, and 80 mg/kg, respectively). The trial lasted for 16 wk consisting of 4 wk depletion period and 12 wk testing period. The results indicated that dietary hydroxychloride trace elements increased egg weight (P < 0.05) when compared with CON group and improved average Haugh unit and albumen height (P < 0.05) when compared with Sulphate group from 70 to 73 wk. Trace element supplementation significantly increased eggshell strength, ceruloplasmin content in serum, and modified crystallographic structure of eggshell (P < 0.05) that included effective layer height, palisade height, mammillary layer width, and mammillary internal area ratio, but the results did not differ regarding the trace mineral sources used. Furthermore, hens fed with hydroxychloride trace element showed the highest mucosal fold height (P < 0.05) and epithelial height (P = 0.053) in eggshell gland, as well as mRNA expression of TNF-α (P < 0.05) and IL-22 (P = 0.094). It is concluded that supplementation of Zn, Cu, and Mn mixture modified eggshell quality partly through enhancing histological structure and immune responses of uterus. Hydroxychloride source of Zn, Cu, and Mn excelled sulphate in its beneficial effects for birds.

Effect of advanced chelate compounds-based mineral supplement in laying hen diet on the performance, egg quality, yolk mineral content, fatty acid composition, and oxidative status

The study aimed to determine the efficiency of advanced chelate compounds-based trace minerals (OTM) in laying hens. Laying hens (240, 32 weeks old) were assigned to one of the following five groups: NOTM (no added trace minerals), CONTM (standard mineral salts), and three experimental groups in which chelates were used to replace 33, 66, and 100% of mineral salts (OTM33, OTM66, and OTM100, respectively). Each treatment had six replicates with eight hens per replicate. After 18 weeks, performance and physicochemical properties of eggs in all experimental groups was better than those in the NOTM group. Among the treatments, OTM66 and OTM100 produced the best results in terms of laying performance, yolk PUFA/SFA ratio, Zn and Se contents, and malondialdehyde concentration in both serum and yolk. In conclusion, up to 66% OTM supplementation was beneficial for performance, lipid and mineral composition of yolk, and oxidative status.