不同营养水平日粮对陕北白绒山羊生长性能和小肠组织SLC7A7、SLC3A1及SLC15A1 mRNA表达的影响

本试验旨在研究日粮营养水平对断奶后2~6月龄陕北白绒山羊生长性能及小肠组织中与氨基酸转运吸收相关的SLC7A7、SLC3A1和SLC15A1 mRNA表达的影响。选取健康、日龄（（60±1.60）d）和体重（（10.73±1.03）kg）相近的雌性陕北白绒山羊羔羊36只，随机分为4组，分别饲喂4种试验日粮，其消化能和粗蛋白质水平分别为标准日粮的85%、100%、115%和130%。标准日粮营养水平参考肉羊饲养标准NY/T816-2004，依据生长阶段（10~19 kg、15~27 kg）和目标增重设置。试验期间，分别于120和180日龄称重，于180日龄，每个重复屠宰1只试验羊，采集十二指肠中上部、空肠中段、回肠末端组织样品，通过实时荧光定量PCR检测SLC7A7、SLC3A1和SLC15A1表达水平。结果表明：1）第一阶段（60~120 d）115%水平组平均日增重显著高于其他三组（P<0.05），第二阶段（121~180 d）115%水平组平均日增重显著高于85%和100%水平组（P<0.05），与130%水平组无明显差异。两阶段115%水平组羔羊干物质采食量极显著高于其他3组（P<0.01）。两阶段料重比115%水平组显著低于85%、100%水平组（P<0.05）。2）相同营养水平下，SLC7A7和SLC15A1 mRNA的表达丰度顺序均为回肠>空肠>十二指肠；3）随日粮营养水平的增加，SLC7A7、SLC3A1和SLC15A1 mRNA在小肠各段的相对表达量呈先上升后下降的趋势，且115%水平组表达量最高。115%水平组SLC7A7和SLC15A1 mRNA相对表达量显著高于其他3组（P<0.05）；115%水平组SLC3A1 mRNA的相对表达量显著高于85%和130%水平组组（P<0.05）。本试验条件下，与其他营养水平组相比，115%水平组陕北白绒山羊羔羊在2~6月龄生长性能最佳，SLC7A7、SLC3A1和SLC15A1 mRNA在小肠各段的表达量最高。     

丙酮酸钙对山羊瘤胃挥发性脂肪酸浓度动态变化的影响

以8只装有永久性瘤胃瘘管的成年徐淮山羊为试验动物,采用自身对照设计,研究丙酮酸钙对山羊瘤胃内挥发性脂肪酸浓度动态变化的影响。结果表明:与对照组相比,添喂丙酮酸钙后,在0~8h内,对pH值无显著影响。4h时,总挥发性脂肪酸(TVFA)浓度升高25%(P<0.01);丙酸浓度升高60%(P<0.01)。0~8h内,丙酸比例均高于对照组(17%~30%);乙丙比均低于对照组(20%~29%)。说明在山羊日粮中添加一定量丙酮酸钙,可在不影响pH值的情况下,提高丙酸比例,降低乙丙比,改变瘤胃发酵类型。     

热应激诱发的氧化应激对羊的影响及其作用机制

热应激会破坏机体氧化系统和抗氧化系统之间的平衡,诱发机体的氧化应激。而机体抗氧化系统与免疫系统息息相关,其中核转录因子E2相关因子2(Nrf2)信号通路是联系二者的重要途径。本文阐述了热应激如何诱导羊发生氧化应激,以及热应激诱导的氧化应激对羊肠道组织、机体免疫细胞及相关细胞因子表达分泌的影响和Nrf2信号通路的调控机制,以期系统理解热应激诱导的氧化应激对羊的影响。     

Effects of stocking density on oxidative stress status and mammary gland permeability in early lactating dairy cows

The current study was conducted to investigate the effect of stocking density (SD) on oxidative stress status and mammary gland permeability in early lactating dairy cows. Thirty‐two dairy cows were allocated into 16 blocks, basing on parity, previous milk yield, and body weight, and were then randomly assigned into one of the two treatments as follows: 75% (75SD) and 100% (100SD) SD. The cows were fed with same diet throughout the 8‐week experimental period. The milk yield and milk sample were collected on two consecutive days during the 8‐week experimental period weekly. Plasma samples were collected on fourth and eighth experimental weeks. Raw, energy‐corrected, and 4% fat‐corrected milk yield were significantly higher in 75SD‐cows than that of 100SD‐animals, respectively. The milk somatic cell count was lower in 75SD‐cows than that of 100SD‐animals. The levels of Na⁺, Na⁺/K⁺, bovine serum albumin and plasmin were lower in 75SD‐cows than those of 100SD‐cattle, respectively. The 75SD‐cows had reduced insulin and insulin/glucagon levels but higher prolactin and growth hormone concentrations, compared with those of 100SD‐animals, respectively. In conclusion, compared with low SD‐animals, early lactating cows with higher SD had higher oxidative stress status, which further led to a greater mammary gland permeability.     

Evaluation of high nutrient diets and additional dextrose on reproductive performance and litter performance of heat‐stressed lactating sows

This study investigated the litter performance of lactating sows fed nutrient‐dense diets with or without dextrose at farrowing to weaning, during the summer with an average room temperature of 28.4°C. A total of 60 (13 first parity, 13 second parity, 19 third parity, and 15 forth parity) cross‐bred sows were assigned to three treatments. The three treatments were: standard diet (ST), high nutrient diet (HN; ST + 3% higher energy and 18.0% protein), and high nutrient diet plus dextrose (HND; 3% higher energy, 18.0% protein, and 5% dextrose). BW loss was reduced in the HND sows compared with the ST sows during lactation. The HN and HND sows had a higher piglet and litter weight at weaning. Also, the HND sows had the highest post‐prandial insulin levels at weaning and the shortest weaning‐to‐service interval (WSI). Serum LH was higher in the HND sows than the ST sows. The milk fat level was higher in the HND sows compared with the ST sows, but similar to the HN sows. In conclusion, these results suggest that it is possible to increase the blood insulin response by supplementing dextrose to a high nutrient diet, thus, improving WSI interval and litter growth during heat stress.     

Effect of chronic administration of a gonadotropin‐releasing agonist on luteal function and pregnancy rates in dairy cattle

Increased embryonic losses may be associated with inadequate progesterone (P4) concentrations in high‐producing lactating dairy cattle. The objectives of the present studies were to determine if chronic administration of a gonadotropin‐releasing hormone (GnRH) agonist, Deslorelin, would increase circulating P4 concentrations and subsequently increase pregnancy rates in dairy cattle. Administration of Deslorelin for 12 days increased (p < .05) luteal volume and circulating P4 concentrations in primiparous lactating dairy cows, but increased only luteal volumes in multiparous cows. Treatment with Deslorelin increased Day 45 pregnancy rates in cows as compared to untreated controls. Chronic treatment with Deslorelin in dairy cattle; (a) increased luteal volume of the primary CL, (b) induced accessory CL, (c) increased circulating P4 concentration in primiparous cows only, (d) did not lengthen the estrous cycle upon removal of treatment, and (e) increased pregnancy rates. Although luteal volume was increased in multiparous cows and circulating P4 concentrations were not with Deslorelin treatment, there was an apparent effect on pregnancy rates. This hormonal strategy may represent a suitable model to address local effects of P4 and GnRH/luteinizing hormone on uterine environment and subsequent embryonic survival.     

不同蛋白质水平饲粮对生长期云上黑山羊能量代谢的影响

为研究不同蛋白质水平饲粮对生长期云上黑山羊能量代谢的影响,选取21只体况良好、体重44.84 kg±2.79 kg的处于生长期的云上黑山羊公羊,随机分为3组,每组7个重复,分别饲喂蛋白质水平为9.80%、11.61%和12.66%的3种不同饲粮。所有试验羊进行44 d的饲养试验(预饲期14 d,正试期30 d),在正试期的第12~17天,从3个试验组中各选择健康、体重相近的5只羊进行消化代谢试验。结果表明:①12.66%蛋白质水平组干物质采食量和摄入总能均显著高于9.80%蛋白质水平组和11.61%蛋白质水平组(P<0.05)。②粪能排泄量11.61%蛋白质水平组最低,且显著低于12.66%蛋白质水平组(P<0.05)。③DE、UE、ECH4、ME和NEp三个蛋白质水平组之间差异均不显著(P>0.05)。④总能消化率、总能代谢率3个蛋白质水平组之间差异均不显著(P>0.05);11.61%蛋白质水平组消化能代谢率显著高于12.66%蛋白质水平组(P<0.05)。⑤生长期云上黑山羊的组织和器官能量3个蛋白质水平组之间差异均不显著(P>0.05);除9.80%蛋白质水平组大肠能量显著高于11.61%蛋白质水平组外(P<0.05),其他胃及肠道能量3个蛋白质水平组之间差异均不显著(P>0.05)。综上,说明不同蛋白质水平对云上黑山羊GE、FE、ME/DE有显著影响,饲粮蛋白质水平为11.61%时能量利用率最佳。     

Short-term transportation in a small vehicle affects the physiological state and subsequent water consumption in goats

We investigated the physiological effects on goats of transportation for one hour in a small truck. We also investigated food and water consumption after transportation. Eight adult goats (four castrated males and four ovariectomized females) were used. Plasma levels of cortisol, glucose and free fatty acids increased significantly within 15 min of the start of transportation, and these higher levels were maintained throughout transportation. These results indicate that transportation in a small truck activates the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system in goats. Despite activation of the sympathetic nervous system, heart rate (HR) in subjected animals during transportation did not differ from during the control animals, which were housed in their usual pen. However, after the transportation had ended and the goats started to eat fodder, HR increased significantly. There was no difference in the amount of food consumption between the control and transported goats. Water consumption in the first three hours after transportation was significantly lower in the transported goats than in the controls for the equivalent period. In the subsequent three hours, however, the transported goats consumed more water than the controls. Consequently, the total water consumption of the transported goats did not differ from that of the controls during the six hours after transportation. In conclusion, short-term transportation with a small vehicle activated the HPA axis and the sympathetic nervous system in goats. HR was not increased during transportation, but after the transportation had ended HR in transported goats was higher than that in control goats. After transportation, goats had consumed the same amount of food as control goats, but water consumption during three hours after the transportation was lower than that of control goats.     

Effects of short period frequent milking on milk yield and udder health in Turkish Saanen goats

The major purpose of this study was to investigate whether increasing milking frequency for a short period (21 days) increases milk yield and milk components and improves udder health throughout lactation in Turkish Saanen goats. Two groups were formed (control, n = 14, treatment, n = 14); balanced by parity, bodyweight and birth type to make them homogenous. Feeding and management practices were the same for both groups. The treatment group was milked four times a day (4×) for 21 days after weaning whereas the control group was milked twice a day (2×). All the animals were milked twice daily thereafter. The pyronin methyl green stain method was used to estimate the somatic cell count (SCC), which is an indication of udder health. This method provided a count that excluded RNA and background noise while including cells with DNA. Repeated measures analyses indicated that overall differences between the 2× and 4× groups were significant for the morning, evening and total test day milk yields, in that values for the 4× group were increased 14.7, 8.8 and 12.1%, respectively. Differences between the groups for SCC were not significant. The results of this study indicate that increasing milking frequency to 4×, even for a short time (21 days), increases overall milk yield throughout lactation in dairy goats.     

外源褪黑激素对罕山白绒山羊绒毛生长相关基因表达差异的影响

试验旨在筛选罕山白绒山羊皮肤毛囊生长脱落相关的关键基因,并揭示外源褪黑激素（Melatonin,MT）对罕山白绒山羊绒毛生长相关基因表达差异的影响。选择10只体重平均为33.3 kg、年龄为20月龄的罕山白绒山为实验动物,分为2组,从2014年12月开始每隔1个月按照2 mg/（kg·BW）的剂量在埋植组绒山羊耳后皮下埋植MT,于2015年9月采集2组罕山白绒山羊皮肤组织进行RNA-Seq测序,对差异表达基因进行筛选、功能注释和富集分析。共筛选获得了475个在埋植组与对照组中差异表达的基因,其中,上调表达基因392个,下调表达基因83个。KEGG富集性分析表明,差异表达基因主要参与白细胞经内皮迁移、趋化因子信号通路、fcγ-R介导的吞噬作用、吞噬体、造血细胞谱系、补体级联和混凝级联、细胞因子—细胞因子受体相互作用、NF-kappa B信号通路、PI3K-Akt信号通路等。PI3K-Akt信号通路可能在褪黑激素调控皮肤毛囊发育中发挥重要作用。研究结果为进一步研究MT影响皮肤毛囊生长的分子机理提供依据。