Purine metabolism in high and low uric acid lines of chickens: de novo uric acid synthesis in isolated hepatocytes and phosphoribosylpyrophosphate amidotransferase activities

Lead exposure induced developmental nephrotoxicity in Japanese quail (Coturnix japonica) via oxidative stress-based PI3K/AKT pathway inhibition and NF-κB pathway activation

Birds are sensitive to environmental pollution and lead (Pb) contamination could negatively affect nearly all avian organs and systems including kidney of excretive system. Thereby, we used a biological model species-Japanese quail (Coturnix japonica) to examine the nephrotoxic effects of Pb exposure and possible toxic mechanism of Pb on birds. Quail chicks of 7-day-old were exposed to 50 ppm Pb of low dose and high dose of 500 ppm and 1000 ppm Pb in drinking water for five weeks. The results showed that Pb exposure induced kidney weight increase while body weight and length reduction. The increase of uric acid (UA), creatinine (CREA) and cystatin c (Cys C) in the plasma suggested renal dysfunction. Moreover, both microstructural and ultrastructural changes demonstrated obvious kidney damages. In particular, renal tubule epithelial cells and glomeruli swelling indicated renal inflammation. Furthermore, changes in the content and activity of oxidative stress markers suggested that Pb caused excessive oxidative stress in the kidney. Pb exposure also induced abnormal apoptosis in the kidney. In addition, RNA sequencing (RNA-Seq) analysis revealed that Pb disturbed molecular pathways and signaling related with renal function. Especially, Pb exposure resulted in an increase in renal uric acid synthesis by disrupting purine metabolism. Pb caused apoptotic increment by inhibiting the phosphatidylinositol-3-kinase (PI3K)/RAC-alpha serine/threonine-protein kinase (AKT) pathway and induced aggravated inflammation by activating Nuclear Factor kappa B (NF-κB) signaling pathway. The study implied that Pb caused nephrotoxicity through structural damages, uric acid metabolism disorder, oxidation imbalance, apoptosis and inflammatory pathway activation.

Effects of Artemisia argyi Powder on Egg Quality, Antioxidant Capacity, and Intestinal Development of Roman Laying Hens

This study was conducted to evaluate the effect of dietary supplementation with Artemisia argyi (A. argyi) on egg quality, serum biochemical, antioxidant capacity, and intestinal development in Roman laying hens. A total of 432 (34-week-old) Roman hens were randomly divided into control group and three experimental groups. The control group was fed a basal diet, and the experimental group was fed a basal diet with 1%, 2%, and 3% A. argyi powder, respectively. The results showed that dietary supplementation of 2% A. argyi to the diet increased egg weight and egg white weight, and the daturic acid (C17:0), stearic acid (C18:0), eicosadienoic acid (C20:2), docosahexaenoic acid (C22:6n-3), α-linolenic acid (C18:3n-3), linoleic acid (C18:2n-6c), and polyunsaturated fatty acid (PUFA) in egg yolk. Meanwhile, the addition of 1∼3% A. argyi decreased serum urea. Moreover, dietary supplementation of 1% A. argyi promoted the antioxidative capacity of the hens by increasing hepatic T-SOD and CAT activities, as well as GSH-Px content. However, the addition of 3% A. argyi to the diet significantly increased the content of malondialdehyde in serum and liver and destroyed the intestinal morphology by increasing duodenal crypt depth. In conclusion, the addition level of A. argyi promoting egg quality and antioxidant capacity was at 2% and 1%, respectively.