猪繁殖与呼吸综合征病毒GXA毒株人工感染仔猪的病理学研究

[目的]探讨PRRSV-GXA毒株对断奶仔猪的致病性。[方法]将12头PRRSV/PCV2抗体和抗原阴性的健康仔猪随机分为感染组（9头）和对照组（3头）,感染组通过口服和肌肉注射方式接种PRRSV-GXA株细胞毒（4ml/头）,对照组接种无病毒的细胞培养液（4ml/头）。感染后第11、14和21天分别剖杀感染组3头和对照组1头,根据临床症状、病理学变化、特异性抗体水平以及病毒核酸等判断其致病性。[结果]仔猪感染PRRSV后第6～10天体温稍微升高,随后逐渐恢复至正常。早期出现短暂的精神沉郁,轻度厌食但没有出现典型临床症状。剖检的病理变化仅见于感染后第21天,有2头感染仔猪肺膈叶前缘出现小的局灶性间质性肺炎,镜检肺泡壁间质增宽,有多量单核细胞和淋巴细胞浸润。在感染后第9天检测到PRRSV特异性抗体,并随着时间呈上升趋势,感染后第21天达到较高值。在4头感染仔猪的肺脏及肺门淋巴结检测到病毒核酸,其中1头仔猪扁桃体也检测到病毒核酸。[结论]PRRSV-GXA毒株对仔猪的毒力较弱,但能刺激机体产生较高水平特异性抗体。     

猪脾转移因子的部分生化和免疫性及其应用

对６只新生仔猪和８只成年猪脾脏提取的转移因子（ＴＦ）分析表明，新生仔猪已有较高含量ＴＦ（４．０１ｍｇ／ｇ），１７种氨基酸百分比与成年猪类似。通过对小鼠腹腔巨噬细胞吞噬功能影响的研究表明：新生仔猪脾ＴＦ已具有明显的免疫活性，但不及成年猪。给初生仔猪注射成年猪转移因子的试验表明，注射ＴＦ对白细胞数（ＷＢＣ），３日龄淋巴细胞增殖均无明显影响，但对４５日龄淋巴细胞有促进作用，对３０日龄至６０日龄增重亦有极     

香猪血清蛋白水平变化与分析

采用临床常规方法对１３头１－６月龄春产香猪的血清总蛋白、白蛋白、球蛋白含量进行了测定与分析。结果表明，不同月龄血清蛋白含量不同，１月龄血清蛋白含量最低，２、３、５、６月龄量含量处于中等水平，４月龄时含量高。     

乙型脑炎病毒感染小鼠原代神经元细胞的miRNA表达谱差异分析

研究乙型脑炎病毒（Japanese encephalitis virus,JEV）感染后小鼠原代神经元细胞miRNA的表达谱差异,初步探讨JEV与宿主在miRNA水平的相互作用。分别提取JEV感染48 h后的小鼠原代神经元细胞和未染毒组细胞,高通量测序分析miRNA的表达谱并进行差异分析,选取显著差异表达的miRNA进行实时定量PCR验证。结果筛选出26个差异表达显著的miRNA,其中,18个表达上调,8个表达下调。小鼠原代脑神经元细胞中mmu-miR-21a-3p、mmu-miR-223-5p、mmu-miR-147-3p、mmu-miR-155-5p和mmu-miR-146a-5p的表达促进JEV-E基因在神经元细胞中表达,而mmu-miR-301a的表达抑制JEV-E基因的表达。神经元细胞中miRNA的表达影响JEV的复制,为进一步研究JEV致神经功能异常机制提供研究方向和理论支持。     

Dietary high protein-induced diarrhea and intestinal inflammation by activation of NF-κB signaling in piglets

The present study aimed to investigate whether inflammation-associated responses in piglets are induced by high protein (HP) through activating nuclear factor kappa B (NF-κB) signaling. Sixteen piglets (35 d of age, Duroc × [Landrace × Yorkshire], weaned at d 21, initial BW = 9.70 ± 0.11 kg) were allocated to 18% and 26% CP (HP group) at random, comprising 8 replicate pens per treatment. The piglets were slaughtered to collect intestinal tissues when apparent, persistent, and stable diarrhea syndromes happened (on d 12). No significant differences were observed in their growth performance (P > 0.05), but reduction by 19.11%, 25.31%, 23.64% of ADFI, ADG, and G:F, respectively was detected in the HP group. The HP group had greater (P = 0.002) diarrhea rates. Furthermore, dietary HP had lower ileal villus height (VH; P = 0.048), ratio of villus height to crypt depth (VH/CD ratio; P = 0.016), and colonic CD (P = 0.034), as well as had the trend (P = 0.075) to reduce the ileal villus absorptive area. Moreover, HP diets significantly elevated the goblet cell numbers in the ileal villi (P = 0.016) and colonic crypts (P < 0.001) and up-regulated (P = 0.012) the mRNA expression of mucin2 (Muc2) in the ileum. In addition, HP diets increased the myeloperoxidase concentration in the ileum (P = 0.002) and colon (P = 0.007) of piglets. Dietary HP significantly down-regulated the mRNA expression of tumor necrosis factor-α (TNF-α; P < 0.001) in the ileum, induced nitric oxide synthase (iNOS; P = 0.040) and interleukin-22 (IL-22; P = 0.008) in the colon, and inclined to down-regulate interleukin-1β (IL-1β; P = 0.076) expression in the colon. The relative protein abundance of Galectin-3 (P = 0.046) in the colon and the ratio of phosphorylation NF-κB to NF-κB (p–NF–κB/NF-κB ratio) in the ileum of HP piglets were also greater (P = 0.038). These results suggest that dietary HP may cause diarrhea in piglets by activating NF-κB signaling induced intestinal inflammation.     

Productivity of Crossbred Dairy Cows Suckling their Calves for 12 or 24 Weeks Post Calving

An experiment on restricted suckling of crossbred dairy cows was conducted at the Livestock Research Centre, Tanga in northeast Tanzania. Thirty-six Bos taurus (Holstein Friesian and Jersey) x Bos indicus (East African Zebu) cows were allocated alternately as they calved to suckling their calves for either 12 or 24 weeks after calving. Cows grazed improved pastures and were offered 4 kg concentrate daily. Milking occurred twice daily by hand; calves were allowed to suck residual milk for 30 min following each milking. Calves were also allowed access to grazing and were offered a maximum of 1 kg concentrate daily to 24 weeks of age. Weaning age had no significant effect on lactation milk yield for human consumption, the mean (SE) yield being 1806 (102.0) L and 1705 (129.1) L for 12- and 24-week weaning, respectively. Cows from the two treatments suffered similar losses of live weight and body condition score during lactation and neither group had returned to the original body condition score 40 weeks following calving. Post-partum anoestrous intervals were prolonged. Although not significant, cows suckling calves to 24 weeks had a mean interval to first oestrus extended by 38 days compared with cows suckling calves to 12 weeks. The mean (SE) daily live weight gains of the calves to 52 weeks were 263 (14.1) g/day and 230 (18.1) g/day for calves weaned at 12 and 24 weeks, respectively, such that 12-month weights were 119 (5.6) kg and 110 (7.3) kg, respectively. Twelve-week-weaned calves consumed more concentrate (p<0.05) from 13 to 24 weeks than did 24-week weaned calves. Calculation of residual milk consumption removed by calves from birth to 12 weeks indicated that it accounted for 28%) of total yield. No benefits in cow and calf performance and welfare were found to justify prolonging the suckling period to 24 weeks.     

Morphological and functional comparison of lingual papillae in suckling and adult feral cats: Forensic evidence

Feral cats are considered as strays and are more likely to hunt in the street. We investigated the effect of environmental adaptations on the structures of lingual papillae in feral cats, which could be used as forensic evidence for their identification. There are no reported studies about the structural comparison of lingual papillae between suckling and adult feral cats. The present study described the lingual papillae of both suckling and adult cats macroscopically and microscopically via light and scanning electron microscopy. A total of nine tongue samples each for suckling and adult feral cats were examined grossly and histologically. Papillae distributions of suckling cats were similar to those observed in adult cats. Meanwhile, the shapes of those papillae were markedly different from that of corresponding papillae in adults. The change in taste bud position and size seemed to be related to the progressive growth of the papillae between adult and suckling cats; absence of taste buds in foliate papillae of feral cats at any stage; and marginal papillae which were a characteristic feature for all suckling cats. All previous elements could be affected by the specific feeding behaviour and mastication mode adaptation in suckling and adult feral cats which might help to identify suckling and adult feral cats among other breeds and animal species. We anticipate these findings may provide promising forensic evidence to discriminate between adult and suckling feral cat remains as well as prediction of environmental harshness and feeding behaviour.     

地塞米松对仔猪十二指肠黏膜免疫的影响

为了探讨地塞米松对仔猪肠道黏膜的影响,选用福州周边某猪场30日龄仔猪30头,随机分为6组,3组为试验组,3组为对照组,试验Ⅰ、Ⅱ、Ⅲ组分别肌肉注射1 mL、2 mL、3 m L地塞米松,对照组Ⅰ、Ⅱ、Ⅲ组分别肌肉注射1 mL、2 m L、3 mL生理盐水;药物试验7 d后,取十二指肠固定、脱水、包埋、切片,经HE染色、阿利新蓝-过碘雪夫(AB-PAS)染色,检测地塞米松对肠道绒毛高度、隐窝深度、绒毛高度和隐窝深度比值、黏液细胞、上皮内淋巴细胞数量的影响。结果表明:长时间过量注射地塞米松抑制肠绒毛生长,显著降低肠绒毛长度和隐窝深度比值,显著性降低仔猪十二指肠上皮酸性黏多糖阳性细胞和上皮内淋巴细胞数量。可见,持续过量注射地塞米松将影响十二指肠黏膜免疫功能。     

Associations between maternal milk protein genotypes with preweaning calf growth traits in beef cattle

The objectives of this study were to investigate milk casein polymorphisms in dams and to determine the impacts of maternal casein genotypes on growth traits of their sucking calves. Milk samples from 433 dams of the breeds German Angus (GA) and German Simmental (GS) were typed at the milk protein loci α _s1-casein (α_s1-CN), β-casein (β-CN), α _s2-casein (α_s2-CN), and κ-casein (κ-CN) via isoelectric focusing. Associations between casein genotypes in maternal milk with growth traits of their 1,872 calves were analyzed until the age of weaning using linear mixed models, considering either genotypes of individual casein loci (model 1) or composite α _s1-β-α _s2-κ-CN genotypes within the casein cluster (model 2). Besides environmental effects such as sex, age of the dam, and calving year-season, genetic effects (breed group and maternal and paternal effects) were considered in statistical models. The composite casein genotype BBǀA2A2ǀAAǀAB (order of genes on bovine chromosome 6: α _s1-ǀβ-ǀα _s2-ǀκ-CN) was associated with greater average daily weight gains (ADG) and heavier age-adjusted weaning weights (WW) of calves (P < 0.05). The effects of composite genotypes on birth weight of calves were similar (P > 0.05; model 2). With regard to individual casein loci, greater ADG and WW were observed for calves from dams with the genotypes κ-CN BB and α _s1-CN BB, respectively (P < 0.05; model 1). Age-adjusted WW was largest for calves from dams carrying the κ-CN genotype BB (215 kg) compared with calves representing the maternal AB and AA genotypes (both 204 kg). Results from the present study suggested selectable casein genotypes due to their nutritional value of milk (value in terms of offspring performances), offering new perspectives for breeding strategies in beef cattle to improve preweaning calf performance.     

饲喂乳酸菌对母猪和哺乳仔猪生长性能、血清生化指标及粪便微生物数量的影响

本试验旨在研究饮水中添加乳酸菌对母猪和哺乳仔猪生长性能、血清生化指标及粪便微生物数量的影响。试验选择相同胎次、妊娠后期(81~85 d)的母猪40头,随机分为4组,每组10头。对照组及3个试验组母猪通过饮水每天每头分别饲喂0、200、250和300 m L乳酸菌液(活菌浓度≥1×109CFU/m L),试验期80 d;对照组及3个试验组哺乳仔猪通过饮水每天每头分别饲喂0、5、10和15 m L乳酸菌液,试验期7 d。结果表明:1)与对照组相比,250 m L乳酸菌液可极显著提高母猪断奶体况评分(P<0.01),试验组母猪断奶后正常发情率和情期受胎率均为100.00%。2)试验组仔猪断奶重、平均日增重、仔猪皮毛发育状况评分较对照组均极显著提高(P<0.01),其腹泻率均有降低趋势。3)与对照组相比,饲喂乳酸菌液显著增加母猪初乳免疫球蛋白G含量(P<0.05),对乳蛋白、乳脂含量以及血清抗氧化指标也有提高趋势;300 m L乳酸菌液使母猪粪便中大肠杆菌、沙门氏菌数量显著减少(P<0.05),而乳酸菌数量显著增多(P<0.05)。试验证明,饲喂乳酸菌能够改善猪肠道微生态和健康状况,提高母猪的繁殖性能和哺乳仔猪的生长性能。