Enhanced Efficiency of Milk Utilization for Growth in Surviving Low-Birth-Weight Piglets

This study determined effects of birth weights （0.70 to 1.09, 1.10 to 1.49, 1.50 to 1.89, and ≥ 1.90 kg） on the efficiency of milk utilization for growth in sow-reared piglets. One-hundred-sixty piglets from 18 multiparous sows （ Landrace × Large White） were individually weighed immediately after birth （ day 0） and at 7-day intervals for 35 days. Milk consumption of piglets was determined weekly using the weigh-suckle-weigh method. Deaths of piglets were recorded daily. Piglets with the lightest birth weight had the highest incidence of mortality. Birth weights between 0.70 and 1.89 kg were positively as- sociated with average dally gains （ADG, g/day ） during the suckling period （ P 〈 0.01 ）. Compared with piglets having birth weights of 1.50 to 1.89 kg, birth weights ≥ 1.90 kg did not confer any additional benefit on preweaning survival or ADG. Colostrum or milk consumption per kilogram of body weight among low-, normal-, and large-birth-weight piglets did not differ in the first week. At days 14 to 35, milk consumption of piglets （ g/kg BW/day ） increased （e 〈 0. 01 ） but the ratio of gain to milk consumption decreased （ P 〈 0.01 ） progressively, as their birth weights increased from 0.70 to ≥1.90 kg. Additionally, surviving low-birth-weight piglets had a higher relative growth rate （%/day ） than normal-and large-birth- weight piglets. Based on these novel findings, it is imperative that great efforts be made to improve the survival of low-birth-weight piglets so as to increase the efficiency of nutrient utilization by both lactating sows and suckling piglets.

Putrescine mitigates intestinal atrophy through suppressing inflammatory response in weanling piglets

Background: Polyamines are essential for cell growth and beneficial for intestinal maturation. To evaluate the effects of putrescine on alleviating intestinal atrophy and underlying molecular mechanisms, both in vivo feeding trial and in vitro cell culture were conducted. Weanling pigs were fed a diet supplemented with 0, 0.1%, 0.2% or0.3% putrescine dihydrochloride, whereas porcine intestinal epithelial cells(IPEC-J2) were challenged with lipopolysaccharide(LPS) in the presence of 200 μmol/L putrescine.Results: Dietary supplementation with 0.2% putrescine dihydrochloride decreased the incidence of diarrhea with an improvement in intestinal integrity. Inhibition of ornithine decarboxylase activity decreased the proliferation and migration of IPEC-J2 cells, and this effect was alleviated by the supplementation with putrescine. The phosphorylation of extracellular signal regulated kinase and focal adhesion kinase was enhanced by putrescine. LPS increased the expression of inflammatory cytokines [tumor necrosis factor α(TNF-α), interleukin 6(IL-6) and IL-8],and inhibited cell proliferation and migration in IPEC-J2 cells. Adding exogenous putrescine suppressed the expression of TNF-α, IL-6 and IL-8, and recovered cell migration and proliferation in LPS-treated IPEC-J2 cells. Dietary putrescine supplementation also reduced the m RNA levels of TNF-α, IL-6 and IL-8 and their upstream regulator nuclear receptor kappa B p65 subunit in the jejunal mucosa of piglets.Conclusions: Dietary supplementation with putrescine mitigated mucosal atrophy in weanling piglets through improving anti-inflammatory function and suppressing inflammatory response. Our results have important implications for nutritional management of intestinal integrity and health in weanling piglets and other neonates.

有机化合物的结构与性质——第35届中国化学奥林匹克(初赛)第8题解析

对第35届中国化学奥林匹克(初赛)试题有机化学模块的第8题展开了详细的解析,题目所考查的内容主要涵盖有机化学的基础理论与有机物的性质。对该题涉及的理论知识、科学背景或解题策略进行了较为深入的点评与拓展,促进读者对有机化学的理解,强化结构决定性质的化学观念。

SnoRNP is essential for thermospermine-mediated development in Arabidopsis thaliana

Polyamines have been discovered for hundreds of years and once considered as a class of phytohormones.Polyamines play critical roles in a range of developmental processes.However,the molecular mechanisms of polyamine signaling pathways remain poorly understood.Here,we measured the contents of main types of polyamines,and found that endogenous level of thermospermine(T-Spm)in Arabidopsis thaliana is comparable to those of classic phytohormones and is significantly lower than those of putrescine(Put),spermidine(Spd),and spermine(Spm).We further found a nodule-like structure around the junction area connecting the shoot and root of the T-Spm biosynthetic mutant acl5 and obtained more than 50 suppressors of acl5 nodule structure(san)through suppressor screening.An in-depth study of two san suppressors revealed that NAP57 and NOP56,core components of box H/ACA and C/D snoRNPs,were essential for T-Spm-mediated nodule-like structure formation and plant height.Furthermore,analyses of rRNA modifications showed that the overall levels of pseudouridylation and 2′-O-methylation were compromised in san1 and san2 respectively.Taken together,these results establish a strong genetic relationship between rRNA modification and T-Spm-mediated growth and development,which was previously undiscovered in all organisms.

In-situ formation of hierarchical solid-electrolyte interphase for ultra-long cycling of aqueous zinc-ion batteries

Aqueous rechargeable zinc ion batteries have received widespread attention due to their high energy density and low cost.However,zinc metal anodes face fatal dendrite growth and detrimental side reactions,which affect the cycle stability and practical application of zinc ion batteries.Here,an in-situ formed hierarchical solid-electrolyte interphase composed of InF3,In,and ZnF2 layers with outside-in orientation on the Zn anode(denoted as Zn@InF3)is developed by a sample InF3 coating.The inner ultrathin ZnF2 interface between Zn anode and InF3 layer formed by the spontaneous galvanic replacement reaction between InF3 and Zn,is conductive to achieving uniform Zn deposition and inhibits the growth of Zinc dendrites due to the high electrical resistivity and Zn2+conductivity.Meanwhile,the middle uniformly generated metallic In and outside InF3 layers functioning as corrosion inhibitor suppressing the side reaction due to the waterproof surfaces,good chemical inactivity,and high hydrogen evolution overpotential.Besides,the as-prepared zinc anode enables dendrite-free Zn plating/stripping for more than 6,000 h at nearly 100%coulombic efficiency(CE).Furthermore,coupled with the MnO2 cathode,the full battery exhibits the long cycle of up to 1,000 cycles with a low negative-to-positive electrode capacity(N/P)ratio of 2.8.

4-Phenylbutyric acid accelerates rehabilitation of barrier function in IPEC-J2 cell monolayer model

As the first line of defence against pathogens and endotoxins crossing the intestine-blood barrier,the intestinal epithelial barrier plays a determinant role in pigs’health and growth.4-Phenylbutyric acid(4-PBA),an aromatic fatty acid,was reported to benefit homeostasis of endoplasmic reticulum and protein synthesis.However,whether 4-PBA affects intestinal epithelial barrier function in pigs is unknown.This study aimed to explore the effects of 4-PBA on the intestinal barrier function,using in vitro models of well-differentiated intestinal porcine epithelial cell(IPEC-J2)monolayers in the transwell plates.Cell monolayers with or without 4-PBA(1.0 mmol/L)treatment were challenged with physical scratch,deoxynivalenol(DON,2.0μg/mL,48 h),and lipopolysaccharide(LPS,5.0μg/mL,48 h),respectively.Transepithelial electrical resistance(TEER)and fluorescein isothiocyanate-dextran(FD-4)permeability were measured to indicate barrier integrity and permeability.Real-time PCR and Western blot were conducted to determine relative gene and protein expressions of tight junction proteins.As expected,physical scratch,DON,and LPS challenges decreased TEER and increased FD-4 permeability.4-PBA treatment accelerated cell mitigation and rehabilitation of the physical scratch-damaged intestinal epithelial barrier but did not alleviate DON or LPS induced barrier damage.However,once 48-h DON and LPS challenges were removed,rehabilitation of the epithelial barrier function of IPEC-J2 monolayer was accelerated by the 4-PBA treatment.Also,the relative gene and protein expressions of zonula occludens-1(ZO-1),occludin,and claudin-1 were further upregulated by the 4-PBA treatment during the barrier rehabilitation.Taken together,4-PBA accelerated the IPEC-J2 cell monolayer barrier recovering from physical scratch,DON-,and LPS-induced damage,via enhancing cell mitigation and expressions of tight junction proteins.

Effects of daidzein on antioxidant capacity in weaned pigs and IPEC-J2cells

Our previous study found that soybean isoflavones in soybean meal play an important role in improving growth performance and antioxidant capacity in pigs.However,it is still unknown whether long-term supplementation with daidzein,an active molecule deglycosylated from daidzin,in a corn-soybean meal diet can enhance growth performance in pigs.Thus,in the present study,an animal trial was carried out to investigate the effects of dietary supplementation with daidzein on the growth performance and antioxidant capacity of pigs.A total of 80 weaned piglets(40 barrows and 40 females)were assigned to 4treatments with 5 pens per treatment and 4 piglets per pen and fed a diet supplemented with 0,25,50 and 100 mg/kg daidzein for a 72-day trial.In addition,porcine intestinal epithelial cells(IPEC-J2)were used as an in vitro model to explore the underlying antioxidant mechanisms of daidzein.IPEC-J2 cells were treated with 0.6 mM hydrogen peroxide(H_(2)O_(2))in the presence or absence of 40μM daidzein.The results showed that adding 50 mg/kg of daidzein to the diet significantly improved body weight on day72,average daily gain(ADG)during days 0 to 72 and plasma superoxide dismutase(SOD)activity on day42,and decreased malondialdehyde(MDA)content on day 14(P<0.05).Treatment with 0.6 m M H_(2)O_(2)for 1 h significantly decreased cell viability and catalase(CAT)activity and increased intracellular reactive oxygen species(ROS)levels and MDA content(P<0.05),while pretreatment with 40μM daidzein prevented the decrease in cell viability and CAT activity and the increase in intracellular ROS levels and MDA content caused by H_(2)O_(2)(P<0.05).In addition,H_(2)O_(2)stimulation significantly suppressed the expression of nuclear factor erythroid-2-related factor 2(Nrf2),CAT,occludin and zonula occludens-1(ZO-1),while pretreatment with daidzein preserved the expression of Nrf2,CAT and occludin in H_(2)O_(2)-stimulated IPEC-J2 cells(P<0.05).In conclusion,our results suggested that long-term dietary supplementation with 50 mg/kg daidzein improved growth performance in pigs and was beneficial to the antioxidant capacity of pigs.Daidzein exerted protective effects against H_(2)O_(2)-induced oxidative stress in IPEC-J2 cells and the underlying mechanism may be related to the activation of the Nrf2 signaling pathway.