Zuowei Su

Dietary overload lithium decreases the adipogenesis in abdominal adipose tissue of broiler chickens

To investigate the toxic effects of dietary overload lithium on the adipogenesis in adipose tissue of chicken and the role of hypothalamic neuropeptide Y (NPY) in this process, one-day-old male chicks were fed with the basal diet added with 0 (control) or 100mg lithium/kg diet from lithium chloride (overload lithium) for 35days. Abdominal adipose tissue and hypothalamus were collected at day 6, 14, and 35. As a percentage of body weight, abdominal fat decreased (p<0.001) at day 6, 14, and 35, and feed intake and body weight gain decreased during day 7-14, and day 15-35 in overload lithium treated broilers as compared to control. Adipocyte diameter and DNA content in abdominal adipose tissue were significantly lower in overload-lithium treatment than control at day 35, although no significant differences were observed at day 6 and 14. Dietary overload lithium decreased (p<0.01) transcriptional expression of preadipocyte proliferation makers ki-67 (KI67), microtubule-associated protein homolog (TPX2), and topoisomerase 2-alpha (TOP2A), and preadipocyte differentiation transcriptional factors peroxisome proliferator-activated receptor-γ (PPARγ), and CCAAT/enhancer binding protein (C/EBP) α mRNA abundance in abdominal adipose tissue. In hypothalamus, dietary overload lithium influenced (p<0.001) NPY, and NPY receptor (NPYR) 6 mRNA abundance at day 6 and 14, but not at day 35. In conclusion, dietary overload lithium decreased the adipogenesis in abdominal adipose tissue of chicken, which was accompanied by depressing transcriptional expression of adipogenesis-associated factors. Hypothalamic NPY had a potential role in the adipogenesis in abdominal adipose tissue of broilers with a short-term overload lithium treatment.

Effect of dietary xylooligosaccharides on intestinal characteristics, gut microbiota, cecal short-chain fatty acids, and plasma immune parameters of laying hens

Abstract This study examined the prebiotic effects of xylooligosaccharides (XOS) on intestinal characteristics, gut microbiota, cecal short‐chain fatty acids, plasma calcium metabolism, and immune parameters of laying hens. A total of 1,080 White Lohmann laying hens (28 wk of age) was assigned to 6 dietary treatments that included XOS at concentrations of 0, 0.01, 0.02, 0.03, 0.04, or 0.05% for 8 weeks. Each treatment had 6 replicates with 10 cages (3 birds/cage). Blood, intestinal tissues, and cecal digesta samples were collected from chickens at the end of the experiment. Villus height, crypt depth, the villus to crypt (VH: CD) ratio, and the relative length of different intestinal sections were evaluated. Additionally, the number of microorganisms and the content of short‐chain fatty acids in cecal digesta samples were determined. Plasma concentrations of immunoglobulin A (IgA), immunoglobulin G, immunoglobulin M (IgM), interleukin 2 (IL‐2), tumor necrosis factor‐&agr;(TNF‐&agr;), 1, 25‐dihydroxyvitamin D3 (1,25(OH)2D3), calcitonin (CT), and parathyroid hormone (PTH) were also determined. The results showed that villus height and the VH: CD ratio of the jejunum were increased (linear, P < 0.01) with the increase in dietary XOS concentration, and the relative length of the jejunum (P = 0.03) was increased significantly in XOS diets. Dietary supplementation of XOS significantly increased (linear, P < 0.01) the number of Bifidobacteria in the cecum; however, total bacteria count, Lactobacillus, and Escherichia coli in the cecum were not affected by XOS supplementation. In addition, inclusion of XOS increased (linear, P < 0.01) the content of butyrate in the cecum; and the content of acetic acid showed a linear increasing trend (P = 0.053) with increasing concentration of XOS in the diets. Supplementation with XOS increased (quadratic, P < 0.05) the content of 1,25(OH)2D3 in plasma. There were no significant differences (P > 0.05) in the content of CT and PTH among dietary treatments. Furthermore, dietary XOS increased contents of IgA (linear, P < 0.05), TNF‐&agr; (linear, P < 0.05), IgM (linear, P < 0.05; quadratic, P < 0.05), and IL‐2 (quadratic, P < 0.05). Taken together, it was suggested that supplemental XOS can enhance the intestinal health and immune function of laying hens by positively influencing the intestinal characteristics, gut microbiota, cecal short‐chain fatty acids, and immune parameters.

The Deposition and Elimination of Glucosinolate Metabolites Derived from Rapeseed Meal in Eggs of Laying Hens

This study was to investigate the deposition and elimination of glucosinolate metabolites including 5-vinyl-1,3-oxazolidine-2-thione (5-VOT) and thiocyanate ion (SCN-) derived from rapeseed meal (RSM) in hen eggs. During 12 weeks accumulation phase, the serum triiodothyronine, thyronine, blood urea nitrogen, kidney index, and thyroid index linearly increased with the RSM at week 12 (P < 0.05). The thyroid histopathology revealed a sign of hyperplastic goiter in hens fed with 17.64-29.40% RSM. The 5-VOT content of eggs (Y, ng/g) was correlated with 5-VOT intake (X2, μg/d·bird) and 5-VOT feeding time (X1, week): Y = 54.94X1 + 0.51X2 - 430.34 (P < 0.01, R2 = 0.80). The SCN- content of eggs (Y, mg/kg) was correlated with RSM intake (X2, μg/d·bird) and RSM feeding time (X1, week): Y = 0.095X1 + 0.302X2 - 0.4211 (P < 0.01, R2 = 0.70). After a 4-week withdrawal of RSM, the 5-VOT and SCN- did not show in eggs. Taken together, 5.88% RSM with dietary supplements of 23.55 mg/kg 5-VOT and 10.76 mg/kg SCN- had no effects on hens with regard to serum parameters, organ index, and thyroid histopathology, and more than 4 weeks withdrawal should be considered for human and hen health.

Long-term effect of dietary overload lithium on the glucose metabolism in broiler chickens

Lithium, like insulin, activates glycogen synthase and stimulates glucose transport in rat adipocytes. To investigate the effect of dietary overload lithium on glucose metabolism in broiler chickens, one-day-old chicks were fed a basal diet supplemented with 0 (control) or 100mg lithium/kg (overload lithium) for 35days. Compared to controls, glucose disappearance rates were lower (p=0.035) 15-120min after glucose gavage, and blood glucose concentrations were lower (p=0.038) 30min after insulin injection in overload lithium broilers. Overload lithium decreased (p<0.05) glycogen and glucose-6-phosphate concentrations in liver, but increased (p<0.05) their concentrations in pectoralis major. Overload lithium increased (p<0.05) mRNA expression of glucose transporter (GLUT) 3 and GLUT9 in liver, and GLUT1, GLUT3, GLUT8, and GLUT9 in pectoralis major, but decreased (p<0.05) cytosolic phosphoenolpyruvate carboxykinase (PEPCK) in liver and mitochondrial PEPCK in pectoralis major. These results suggest that dietary overload lithium decreases glucose tolerance and gluconeogenesis, but increases insulin sensitivity and glucose transport in broiler chickens.