A simple daily dynamic feeding regimen for reducing phosphorus consumption and excretion in laying hens

Phosphorus metabolism in laying hens is a highly dynamic process over the course of the 24 h egg-laying cycle.Adjusting the phosphorus feeding regimen according to the daily egg-laying cycle may help to improve phosphorus utilization efficiency.Hy-Line Brown layers(n=120;70 wk old)were offered 4different phosphorus daily regimens:(1)RR,fed regular phosphorus at both 09:00 and 17:00;(2)RL,fed regular phosphorus at 09:00 and low phosphorus at 17:00;(3)LR,fed low phosphorus at 09:00 and regular phosphorus at 17:00;(4)LL,fed low phosphorus at both 09:00 and 17:00.The regular and low phosphorus diets contained 0.32% and 0.14% non-phytate phosphorus,respectively.The feeding trial lasted for 12 wk.As a result,layers on the RL regimen had decreased laying rate(P<0.05;5 to 8,9 to 12,and 1 to 12 wk)when compared to all other regimens.Layers on the LL regimen had decreased eggshell thickness and specific gravity(P<0.05;wk 8)when compared to all other regimens,and had decreased egg shell strength(P<0.05;wk 8)when compared to RL and LR regimens.When compared to the RR regimen(a common practice in the industry),layers on the LR regimen had:(1)identical laying performance and egg quality(P>0.05);(2)decreased phosphorus excretion(P<0.05)during the period of09:00 to 17:00;(3)increased jejunal calbindin D28k protein expression(P<0.05)2 h after feeding in the morning;(4)decreased serum fibroblast growth factor 23 and calcitriol levels(P<0.05),decreased jejunal type Ⅲ sodium-phosphate cotransporter 2 gene and protein expression(P<0.05),and decreased renal type Ⅲ sodium-phosphate cotransporter 1 protein expression(P<0.05),2 h after feeding in the afternoon.In summary,when dietary phosphorus was supplemented in accordance with daily serum phosphorus rhythms(i.e.,the LR regimen),laying performance and egg quality were well supported whilst significantly decreasing phosphorus consumption and excretion.Thus,serum phosphorus rhythms will need to be carefully maintained when developing dietary phosphorus-reduction strategies in laying hens.

Application of three-dimensional digitalized reconstruction of latissimus dorsi myocutaneous flap

Developments of digital technology and three-dimensional(3D)reconstruction allowed a precise description of anatomic structures.With the introduction of Visible Human Project and Virtual Chinese Human(VCH)techniques,more detailed anatomic images could be obtained.Digitized visible models of these structures can be applied as a useful tool in clinical training.The aim of this study was to reconstruct the normal structures of thoracodorsal artery in 3D images and to establish the digitized visible models of latissimus dorsi myocutaneous(LDM)flap.The cross-sectional images from the four VCH datasets were reviewed to study LDM and thoraco-dorsal artery structures on a section-by-section basis.Next,two adult fresh cadaver specimens were perfused with lead oxide-gelatine mixture and subject to radio-graphic CT scanning on their torsos.The cross-sectional images from the CT images were reviewed to study thor-acodorsal artery structures.Three-dimensional computer-ized reconstructions of LDM flap structures were conducted from these datasets by using Amira 3.1(TGS)software respectively.The 3D reconstructed visible models established from these datasets perfectly displayed the anatomic characteristics of LDM flap.

Dietary vitamin D_(3) deprivation suppresses fibroblast growth factor 23 signals by reducing serum phosphorus levels in laying hens

The present study was carried out to evaluate the effect of dietary supplemental vitamin D_(3) on fibroblast growth factor 23(FGF23)signals as well as phosphorus homeostasis and metabolism in laying hens.Fourteen 40-week-old Hy-Line Brown layers were randomly assigned into 2 treatments:1)vitamin D_(3) restriction group(n=7)fed 0 IU/kg vitamin D_(3) diet,and 2)regular vitamin D_(3) group(n=7)fed 1,600 IU/kg vitamin D_(3) diet.The study lasted for 21 d.Serum parameters,phosphorus and calcium excretion status,and tissue expressions of type II sodium-phosphate co-transporters(NPt2),FGF23 signals and vitamin D_(3) metabolic regulators were determined.Hens fed the vitamin D_(3) restricted diet had decreased serum phosphorus levels(by 31.3%,P=0.028)when compared to those fed regular vitamin D_(3) diet.In response to the decreased serum phosphorus,the vitamin D_(3) restricted laying hens exhibited:1)suppressed kidney expressions of 25-hydroxyvitamin D 1-a-hydroxylase(CYP27B1,by 52.8%,P=0.036)and 1,25-dihydroxyvitamin D 24-hydroxylase(CYP24A1,by 99.4%,P=0.032);2)suppressed serum levels of FGF23(by 14.6%,P=0.048)and increased serum alkaline phosphatase level(by 414.1%,P=0.012);3)decreased calvaria mRNA expressions of fibroblast growth factor receptors(FGFR1,by 85.2%,P=0.003,FGFR2,by 89.4%,P=0.014,FGFR3,by 88.8%,P=0.017,FGFR4,by 89.6%,P=0.030);4)decreased kidney mRNA expressions of FGFR1(by 65.5%,P=0.021),FGFR4(by 66.0%,P=0.050)and KLOTHO(by 68.8%,P=0.038);5)decreased kidney protein expression of type 2a sodium-phosphorus co-transporters(by 54.3%,P=0.039);and 6)increased percent excreta calcium(by 26.9%,P=0.002).In conclusion,the deprivation of dietary vitamin D_(3) decreased FGF23 signals in laying hens by reducing serum FGF23 level and suppressing calvaria and kidney mRNA expressions of FGF23 receptors.