The Effect of Different Levels of Dietary Magnesium on Eggshell Quality and Laying Hen's Performance

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 DIFFERENT INTERVAL SPEED TRAINING ON ATHLETE REACTION

ABSTRACT Introduction: High-intensity Intermittent Training (HIIT) ranked first in the ACSM “2013 Global Training Methodology Survey”. Objective: To explore the influence of different speed training intervals on athlete reaction speed. Methods: Sixteen male bicycle athletes were randomly divided into two groups. The two groups then completed a six-week training routine (NT). The two groups then completed a six-week training routine , started 6 weeks of Sprint Interval Training (SIT) (a total of 12 lessons), with SIT instead of Normal Training (NT) live endurance training, and another training remains unchanged. Results: After 6 weeks of NT, Pmax GXT in the CG and DG groups decreased by 0.7% and 1.7%, respectively,as compared to the pre-training numbers. The difference was not statistically significant (P>0.05). And after 6 weeks of SIT, Pmax GXT increased significantly (P<0.05) in both experimental groupss,with increases of 9.2% and 10.2% for the CG and DG groups, respectively. Conclusions: The results show that intermittent training can effectively improve the aerobic metabolism of short-haul cyclists. As the power bicycle load and the training intensity and volume of the deceleration intermittent training program increase, the more significant the changes in aerobic capacity that can result in adaptability. Level of evidence II; Therapeutic studies - investigation of treatment results.