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The effect of the application of copper waterline on the performance and gut health of aged laying hens was evaluated in this study. Forty-eight 70-week-old laying hens were divided into two groups (three replicates of eight hens each): control and copper (Cu) groups provided with normal polyvinyl chloride (PVC) waterline or Cu waterline. The laying performance was measured during the four-week period of the experiment. The intestinal antioxidant status and the microbiota diversity of the cecal content were determined. Moreover, a bacteriostasis test on Escherichia coli and Salmonella enteritidis was conducted after inoculation in waterline and hens, respectively. The water Cu2+ content was increased by Cu waterline compared to the control (P<0.05). Cu waterline had no detectable effect on most production performances, however, it increased the egg weight (P<0.05). Cu waterline increased the Cu level in the eggshell. Cu level in excreta increased with time, especially in the final two weeks, however, there was no significant change in fecal Cu excretion. The lipid peroxidation product malondialdehyde content in ileum decreased (P<0.01), while the activities of CuZn-superoxide dismutase (SOD) of ileum and glutathione peroxidase (GSH-PX) activity of jejunum and ileum increased after Cu treatment. The relative abundance and richness of cecal microbiota increased after Cu treatment (P<0.05). Cu waterline changed the microbial composition, including the increased proportion of Methanocorpusculum, Paludibacter, and decreased proportion of Fucobacterium, Anaerobiospirillum, and Campylobacter. The colonization of E. coli and S. enteritidis in Cu waterline was suppressed by Cu treatment, indicating that Cu waterline had potential antibacterial properties. The result suggests that Cu waterline could inhibit the colonization of pathogenic microorganisms such as E. coli and Salmonella and facilitate the enrichment of cecal microbiota diversity. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of dietary supplementation of calcium propionate and calcium butyrate on the laying performance, eggshell quality, and expression of genes related to calcium and phosphorus metabolism in the tibia. One hundred and twenty 70-week-old Isa Brown hens were randomly assigned to three treatments, and each treatment had four replicates of 10 birds fed a basal diet (control) or a basal diet supplemented with 0.5% calcium propionate (CP) or 0.5% calcium butyrate (CB) for 8 weeks. The CB and CP treatments had no significant effect (P>0.05) on the laying rate, egg production, egg weight, and feed efficiency. The eggshell percentage was increased from week 2 (P<0.05) and eggshell thickness was elevated at week 8 (P<0.01) by both CP and CB treatments. Compared to the control treatment, the CB treatment increased serum calcium and phosphorus levels at week 4 (P<0.05), whereas the CP and CB treatments decreased serum phosphorus at weeks 6 and 8, respectively (P<0.05). Dietary supplementation had no effect on the bone index and bending strength of the tibia (P> 0.05). The calcium and phosphorus content of the tibia was decreased by the CB treatment (P<0.05). In the spleen, NF-κB and IL-6 transcript levels were not influenced (P>0.05) but TNF-α transcript levels were decreased by the CP treatment (P<0.05). In the tibia, the expression levels of NF-κB, TNF-α, and IL-17 were not affected by the CP or CB treatment (P>0.05). The CP and CB treatments had no significant effect on the transcript levels of RANKL, OPG, RNUX2, OPN, α-Clotho, and VDR (P>0.05). In contrast, PHEX transcript levels were increased by the CP treatment (P<0.05). The expression levels of osteocalcin (P=0.094) and FGF23 (P=0.087) tended to decrease under the CB treatment. In conclusion, dietary supplementation of 0.5% calcium butyrate or 0.5% calcium propionate improved the eggshell quality of aged laying hens, possibly as a result of decreased deposition or enhanced mobilization of bone calcium and phosphorus. [ABSTRACT FROM AUTHOR]