Genome-wide differences in DNA methylation changes in caprine ovaries between oestrous and dioestrous phases

Background: DNA methylation plays a vital role in reproduction.Entire genome DNA methylation changes during the oestrous phase(ES) and dioestrous phase(DS) in the ovaries of Guanzhong dairy goats were investigated using bisulphite sequencing to understand the molecular biological mechanisms of these goats' oestrous cycle.Results: We discovered distinct genome-wide DNA methylation patterns in ES and DS ovaries.A total of 26,910 differentially methylated regions were upregulated and 21,453 differentially methylated regions were downregulated in the ES samples compared with the DS samples(P-values ≤0.05 and fold change of methylation ratios ≥2).Differentially methylated region analysis showed hypomethylation in the gene body regions and hypermethylation in the joining region between upstream regions and gene bodies.The methylation ratios of the STAR,FGF2,FGF12,BMP5 and SMAD6 genes in the ES samples were lower than those of the DS samples(P-values≤0.05 and fold change of methylation ratios ≥2).Conversely,the methylation ratios of the EGFR,TGFBR2,IGF2 BP1 and MMD2 genes increased in the ES samples compared with the DS samples.In addition,223 differentially methylated genes were found in the GnRH signalling pathway(KO04912),ovarian steroidogenesis pathway(KO04913),oestrogen signalling pathway(KO04915),oxytocin signalling pathway(KO04921),insulin secretion pathway(KO04911) and MAPK signalling pathway(KO04010).Conclusions: This study is the first large-scale comparison of the high-resolution DNA methylation landscapes of oestrous and dioestrous ovaries from dairy goats.Previous studies and our investigations have shown that the NR5 A2,STAR,FGF2 and BMP5 genes might have potential application value in regulating caprine oestrus.     

Dynamics of methanogenesis,ruminal fermentation and fiber digestibility in ruminants following elimination of protozoa: a meta-analysis

Background: Ruminal microbes are vital to the conversion of lignocellulose-rich plant materials into nutrients for ruminants.Although protozoa play a key role in linking ruminal microbial networks,the contribution of protozoa to rumen fermentation remains controversial; therefore,this meta-analysis was conducted to quantitatively summarize the temporal dynamics of methanogenesis,ruminal volatile fatty acid(VFA) profiles and dietary fiber digestibility in ruminants following the elimination of protozoa(also termed defaunation).A total of 49 studies from 22 publications were evaluated.Results: The results revealed that defaunation reduced methane production and shifted ruminal VFA profiles to consist of more propionate and less acetate and butyrate,but with a reduced total VFA concentration and decreased dietary fiber digestibility.However,these effects were diminished linearly,at different rates,with time during the first few weeks after defaunation,and eventually reached relative stability.The acetate to propionate ratio and methane production were increased at 7 and 11 wk after defaunation,respectively.Conclusions: Elimination of protozoa initially shifted the rumen fermentation toward the production of more propionate and less methane,but eventually toward the production of less propionate and more methane over time.     

犬食盐中毒诊治1例

犬食盐中毒在临床病例中较为少见,原因在于不同动物对食盐的敏感性不同,鸡和猪最为敏感,而犬的肾脏有非常好的排泄功能,对食盐并不敏感。但养犬者饲养管理方法不当。也会造成犬食盐中毒。笔眷在宠物门诊学习期间。遇到一例犬食盐中毒的病例。经过快速诊断和及时有效的救治。病犬成功治愈。     

6个种源地不同桑树品种叶柄解剖结构与水分运输能力初探

叶柄是水分和营养物质在茎和叶间运输的重要组织。采用石蜡切片技术和木材离析技术,分析6个种源地不同的桑树品种一年生扦插苗叶柄的显微结构特征,对叶柄的水分运输能力和抗蒸腾能力进行评价,并对桑树的抗旱性进行探讨。结果显示在6个桑品种中,吴堡桑的叶柄角质层和厚角组织厚度较小,但维管束最为发达,具有较高的维管束面积占比、中等水平的导管直径和最大的导管长度,水分运输能力最强,同时还能保持对栓塞较强的抵抗性,推测其抗旱能力可能较强,适宜种植在较为干旱的地区;育711号的叶柄角质层较薄,云果桑1号叶柄的厚角组织最薄,这2个品种的叶柄具有较多的维管束,但其维管束面积占比、导管孔腔面积以及导管直径在6个品种中较小,故抗蒸腾能力与水分运输能力均较低,其抗旱能力可能相对较弱,更加适合在水分充足的环境中生长。研究结果为阐释桑树叶柄结构、水分运输能力与桑树抗旱能力之间的关系提供了一定的实验依据。     

不同添加剂对紫花苜蓿拉伸膜裹包青贮饲料品质的影响

为明确葡萄糖、红糖、果渣对紫花苜蓿拉伸膜裹包青贮饲料青贮品质的影响,探明最适合添加于紫花苜蓿裹包青贮的有机添加剂,按照紫花苜蓿原料重量的0.2%、0.4%、10%分别添加葡萄糖、果糖、果渣进行90 d青贮。结果表明:添加葡萄糖可保留紫花苜蓿中更多的干物质,有效提高青贮饲料中的乳酸含量,降低乙酸和丙酸含量;添加红糖不利于青贮饲料pH值的降低和乳酸积累,能产生较高的氨态氮、乙酸和丙酸含量;添加果渣虽然可以降低青贮饲料的pH值,但会造成显著的粗蛋白损失。综合分析认为,添加葡萄糖对提高紫花苜蓿拉伸膜裹包青贮饲料青贮品质效果较好。     

Pharmacokinetics of altrenogest in gilts

Altrenogest, a synthetic progestogen, is characterized by its estrus synchronization in mares, ewes, sows, and gilts. To investigate the pharmacokinetic profile and evaluate its accumulation in gilts, 18 oral doses of 20 mg altrenogest/gilt/day were given to eight healthy gilts at an interval of 24 hr. Plasma samples were collected, and altrenogest was determined by ultra‐high‐performance liquid chromatography with mass spectrometry. WinNonlin 6.4 software was used to calculate the pharmacokinetic parameters through noncompartmental model analysis. After the first administration (D 1), the pharmacokinetic parameters, including T_max, C_max, and the elimination half‐life (T_1/2λz), were similar to those observed after the final administration (D 18). However, the mean residence time at D 1 was significantly lower than D 18. As a whole, the mean steady‐state plasma concentration (C_ss), degree fluctuation (DF), accumulation factor (R_ac), and area under the plasma concentration–time curve in steady state (AUC_ss) were 22.69 ± 6.15 ng/ml, 270.64 ± 42.51%, 1.53 ± 0.23, and 544.63 ± 147.49 ng hr/ml, respectively. These results showed that after 18 consecutive days of oral administration of altrenogest, plasma concentrations of altrenogest had a certain degree of fluctuation, without significant accumulations.     

Tilmicosin enteric granules and premix to pigs: Antimicrobial susceptibility testing and comparative pharmacokinetics

The purpose of this study was to compare the pharmacokinetics and relative bioavailability of tilmicosin enteric granules and premix after oral administration at a dose of 40 mg/kg in pigs. Three kinds of different respiratory pathogens were selected for determination of minimal inhibitory concentration (MIC) to tilmicosin. Eight healthy pigs were assigned to a two‐period, randomized crossover design. A modified rapid, sensitive HPLC method was used for determining the concentrations of tilmicosin in plasma. Pharmacokinetic parameters were calculated by using WinNonlin 5.2 software. The MIC₉₀ of tilmicosin against Haemophilus parasuis, Actinbacillus pleuropneumoniae, and Pasteurella multocida were all 8 μg/ml. These results indicated that these common pig respiratory bacteria are sensitive to tilmicosin. The main parameters of time to reach maximum plasma concentration (T_max), elimination half‐life (t_1/2β), mean residence time (MRT), and apparent volume of distribution (V_F) were 2.03 ± 0.37 hr, 29.31 ± 5.56 hr, 25.22 ± 2.57 hr, 4.06 ± 1.04 L/kg, and 3.05 ± 0.08 hr, 17.06 ± 1.77 hr, 15.55 ± 1.37 hr, 2.95 ± 0.62 L/kg after the orally administrated tilmicosin enteric granules and premix. The relative bioavailability of tilmicosin enteric granules to premix was 114.97 ± 7.19%, according to the AUC_0‐t values. These results demonstrated that tilmicosin enteric granules produced faster tilmicosin absorption, slower elimination, larger tissue distribution, and higher bioavailability compared to the tilmicosin premix. The present study results manifest that tilmicosin enteric granules can be used as a therapeutic alternative to premix in clinical treatment.     

母兔腹腔镜辅助微创卵巢子宫切除术

母兔卵巢子宫摘除术为异宠临床诊疗中常见的手术之一,本手术为使用腹腔镜辅助,配合电凝刀进行母兔卵巢子宫摘除微创手术。手术麻醉采用右美托咪定诱导麻醉,气管插管后给予异氟烷混合纯氧吸入麻醉进行维持麻醉。利用气腹仪充入CO2提供腹腔内可进行手术的操作空间,使用腹腔镜配合电凝刀在动物腹腔内电凝及切断双侧卵巢血管及韧带,并牵引卵巢子宫至体外结扎子宫颈。手术平均用时30 min,术后平均5 min恢复自主意识,手术创口为三个大约5 mm的切口,术后预后良好。     

南疆杏李园梨小食心虫成虫消长动态及迷向防治效果

为明确南疆新兴特色水果杏李上梨小食心虫Grapholita molesta（Busck）的发生规律和迷向防治效果,于2021—2022年在新疆维吾尔自治区阿克苏地区杏李园采用性诱剂诱集法监测梨小食心虫种群动态,评估性信息素迷向丝对梨小食心虫的防治效果。结果表明,梨小食心虫在阿克苏杏李园1年发生4代,其中越冬代羽化高峰期在4月上中旬,第1代羽化高峰期在5月下旬至6月上旬,第2代羽化高峰期在7月上旬,第3代羽化高峰期在8月上中旬,存在世代重叠现象。2022年农户常规防治区内梨小食心虫的蛀果率为2.46%,性信息素迷向防治区内蛀果率为0.06%; 2021年和2022年使用性信息素迷向丝对梨小食心虫的蛀梢减退率为98.13%和88.65%,2022年的蛀果减退率为98.40%;对不同世代梨小食心虫的雄成虫迷向率在2021年为92.87%~100.00%,雌、雄成虫虫口减退率在2022年为58.75%~81.37%。表明采用梨小食心虫性信息素迷向丝为主的综合防控技术,可有效控制南疆杏李园梨小食心虫的发生与为害。     

实时荧光定量聚合酶链反应原理和在预防兽医学中的应用及研究进展

聚合酶链反应(PCR)是检测核酸的强力方法。由于PCR技术简便易行、灵敏度高等优点,该技术被广泛应用于基础研究,成为分子生物学必不可少的研究工具。由于传统的PCR技术存在不能准确定量,且操作过程中易污染而使得假阳性率高等缺点,使其应用受到局限。