Effect of single-sex or mixed rearing and live weight on performance,technological meat quality and sexual maturity in entire male and female pigs fed raw potato starch

Abstract

The aim of our study was to investigate the effect of rearing system (mixed or single-sex) on performance and carcass quality of entire male and female pigs slaughtered at around 90 or 115 kg live weight. We also studied the combined effect of live weight and dietary supplement of raw potato starch (RPS) on technological meat quality for both sexes, and boar taint compounds in entire male pigs. Furthermore, we investigated pre-slaughter routines (pen-wise or mixing with unfamiliar pigs) and sexual maturity. A total of 408 growing/finishing pigs were included in this two-year study. Performance did not differ significantly between entire male and female pigs irrespective of rearing system, except for daily weight gain in the interval from 90 kg to slaughter. Mixed pigs had significantly higher daily weight gain in this interval than single-sex pigs. Entire male pigs had higher carcass lean meat content than female pigs (1.6 percentage units). Technological meat quality differed only slightly between the sexes. Females reared in mixed pens were sexually more mature than female pigs reared in single-sex pens, and mature females had higher growth rate but lower meat content in carcasses than immature females. In contrast, female contact did not influence sexual maturity of entire male pigs. Mixing entire male pigs with unfamiliar pigs at the abattoir resulted in more damaged skin compared with pen-wise keeping whereas female pigs had almost no visible skin damage. We therefore recommend that entire male pigs are not mixed with unfamiliar pigs during transport and at the abattoir, because of fighting and subsequent skin damage. The levels of skatole in fat were significantly lower in high-weight entire male pigs fed RPS compared to high-weight pigs without RPS. Androstenone levels in fat were high in all groups.     

海藻糖、蔗糖和乳糖对猪精液冷冻保护效果的影响

比较了在冷冻保存液中添加不同水平海藻糖、蔗糖和乳糖对猪精液冷冻保护的效果。结果表明,添加3种双糖均能提高精液的冷冻保护效果,其最佳添加水平均为0.035 g/mL,在该添加水平下,海藻糖组的精子活率、活力和精子质膜完整率分别为(46.34±0.52)%,(41.38±0.39)%和(43.51±1.78)%,与蔗糖组差异均不显著(P>0.05),但均显著高于乳糖和对照组(P<0.05);海藻糖组的有线粒体活性精子百分率和精子顶体完整率分别为(44.56±1.16)%,(64.09±0.81)%,显著高于蔗糖、乳糖和对照组(P<0.05),3种双糖均随添加水平升高精子的顶体完整率逐渐升高;海藻糖组获能处理前后的精子获能率分别为(3.68±0.07)%和(41.82±0.56)%,显著优于蔗糖、乳糖和对照组(P<0.05)。说明海藻糖对猪精液冷冻保护的效果最好,最佳添加水平为0.035 g/mL。     

Infectivity of porcine circovirus type 2 DNA in semen from experimentally-infected boars

Porcine circovirus type 2 (PCV2) is an economically important pathogen. It has been demonstrated that PCV2 DNA can be detected in boar semen by PCR; however, the biological relevance of this is unknown. The objectives of this study were to determine if semen positive for PCV2 DNA is infectious (1) in a swine bioassay, or (2) when used for artificial insemination. For the first objective, 4-week-old pigs were inoculated intraperitoneally with PCV2 DNA-negative (bioassay-control; n = 3), PCV2a DNA-positive (bioassay-PCV2a; n = 3), or PCV2b DNA-positive (bioassay-PCV2b; n = 3) raw semen, or PCV2 live virus (bioassay-positive; n = 3), respectively. Pigs inoculated with PCV2 DNA-positive semen and PCV2 live virus became viremic and developed anti-PCV2 antibodies indicating that the PCV2 DNA present in semen was infectious. For the second objective, three Landrace gilts were inseminated with PCV2 DNA-negative semen (gilts-controls) from experimentally-infected boars, and six gilts were artificially inseminated with semen positive for PCV2a DNA (gilts-PCV2a; n = 3) or PCV2b DNA (gilts-PCV2b; n = 3). Serum samples collected from the gilts in all groups remained negative for anti-PCV2 antibodies for the duration of the experiment. In addition, fetal serum samples from all 105-day-gestation fetuses were negative for anti-PCV2 antibodies or PCV2 DNA. Under the conditions of this study, PCV2 DNA-positive semen was not infectious when used to artificially inseminate gilts; however, it was demonstrated to be infectious in a swine bioassay model and therefore is a potential means of PCV2 transmission amongst swine herds.     

猪精液常温保存效果观察

为研究不同保存条件对猪精液常温保存效果的影响,观察精子的活力和有效保存时间之间的关系,采用常温下对精液添加抗生素、不同精液稀释比例、光照、振荡、混入尿液等,每隔12 h 显微镜检测一次精子活力的方法,以筛选常温下猪精液保存方式。结果显示,在精液保存过程中加入抗生素时,精液有效保存时间和精子活力明显高于未加抗菌药物的稀释液,其中加入庆大霉素的保存效果最好;精液稀释比例为1∶1～1∶2时保存效果最好;光照及剧烈振荡条件下,精液活力下降很快;混入尿液很容易使精子死亡。上述研究结果表明,常温下猪精液的理想保存方式是,在保证精子密度的前提下,精液与稀释液比例为1∶1～1∶2;同时在精液稀释液中添加广谱抗生素;保存过程中应避免光照、振荡、尿液污染等的影响。     

温氏WS501配套系母系种猪繁殖特性

温氏WS501配套系母系种猪源于清远原种猪场二区,本文对该猪场2014-2017年繁殖相关的数据进行统计及分析。通过10年的选育,其种母猪有发情早、情期多、长速快、开配日龄早和产仔数多的特性;种公猪有体型壮硕、长速快、精液量多、品质高的特性。结果可以为优良品种选育提供科学依据。     

Effect of local scrotal heating on the expression of tight junction‐associated molecule Occludin in boar testes

The aim of this study was to determine whether local scrotal heating (42°C, for 1 hr) had an effect on the expression of tight junction (TJ)‐associated molecule Occludin in boar testes. Adult boars (Landrace, n = 6) were used and randomly divided into two groups (n = 3 each). Three boars were given local scrotal exposure to 42°C for approximately 1 h with a home‐made electric blanket of controlled temperature as local scrotal heating group, the other three boars received no heat treatment and were left at standard room temperature as control group. After 6 hr, all boars were castrated and the testes were harvested. qRT‐PCR, Western blotting and immunohistochemistry were used to explore the expression and localization of Occludin. qRT‐PCR and Western blotting showed that the protein and mRNA levels of Occludin significantly decreased in local scrotal heating group as compared to the control. Furthermore, immunoreactivity staining of Occludin was localized at the sites of the blood–testis barrier (BTB) and formed an almost consecutive and strong immunoreactivity strand in the control, while Occludin was limited to Sertoli cells (SCs) and no obvious immunoreactivity strand was present in local scrotal heating group. These data indicated that local scrotal heating decreased the expression of TJ‐associated molecule Occludin, which may be involved in heat‐induced spermatogenesis damage.     

猪精液中五种病毒的初步检测

为探明猪精液在疫病传播中的作用,应用PCR和RT-PCR技术分别从发病猪场和未发病猪场采集种公猪精液进行猪瘟病毒(CSFV)、猪繁殖与呼吸综合征病毒(PRRSV)、猪伪狂犬病病毒(PRV)、猪圆环病毒2型(PCV-2)和牛病毒性腹泻病毒(BVDV)的检测。结果发现,发病猪场的种公猪精液中CSFV、PRRSV、PRV、PCV-2的感染率分别为30.0%、50.0%、4.0%和30.0%,而未发病猪场的感染率分别为4.0%、20.0%、0.0%和8.0%,这表明精液是多种猪病原传播的良好媒介,提示种公猪对于疫病的发生和传播起着重要作用。     

实时精子分离系统对猪精子冷冻品质的影响

【目的】探索实时精子分离系统对猪精子冷冻品质的影响。【方法】采用实时精子分离系统对精液进行分离优选,液氮冷冻法制作细管冻精,以未分离精液为对照,检测实时精子分离系统对猪精子冷冻品质的影响。【结果】分离优选精子解冻后,精子活率、顶体完整率、质膜完整率、正常染色质率均明显高于对照组(P<0.01);分离组精子的正常形态率也显著高于对照组,且未受冷冻-解冻过程的影响(P>0.01);分离过程对精子密度也未产生显著影响(P>0.01)。【结论】实时精子分离系统可以显著改善猪冷冻精液的品质。     

野猪源与家猪源PRRSV陕西流行毒株对仔猪的致病性试验

【目的】研究野猪源Shaanxi-2及家猪源Shaanxi-1猪繁殖与呼吸综合征病毒(PRRSV)变异株对易感仔猪的致病性及发病规律,进一步弄清PRRSV变异株的病原特征及其与"猪高热病"发生的关系。【方法】选取PRRSV和猪圆环病毒2型(PCV2)抗原、抗体检测均为阴性的健康仔猪(40日龄)9头,随机分为3组,用家猪源Shaanxi-1及野猪源Shaanxi-2 PRRSV变异株分别感染其中一组仔猪,每头肌注6 mL,滴鼻2 mL;另一组作为阴性对照,按相同剂量和方法接种正常Marc-145细胞处理液。攻毒后各组分圈饲养,每天定时测量体温,绘制体温变化曲线,观察临床症状,记录发病情况。攻毒后采血及咽喉、眼、鼻分泌物和粪便,采用RT-PCR方法检测PRRSV、猪瘟病毒(CSFV)、PCV2、猪伪狂犬病毒(PRV)核酸,用ELISA试验及血清中和试验检测血清抗体。【结果】Shaanxi-1与Shaanxi-2攻毒组均出现体温升高及典型临床症状,但未见死亡病例;攻毒组CSFV、PCV2、PRV核酸检测均为阴性,咽喉、眼、鼻分泌物和粪便在一定时间段可检测到PRRSV核酸;PRRSV特异性抗体检测均为阳性,仅Shaanxi-2攻毒组在第35天检测到中和抗体;Shaanxi-2与Shaanxi-1相比,感染猪的体温较高,临床症状明显,病毒血症的维持时间较长,抗体水平较高。【结论】野猪源Shaanxi-2及家猪源Shaanxi-1 PRRSV变异株对易感仔猪具有一定的致病性,能使感染动物发病但不能致死,Shaanxi-2毒株的致病性相对较强。攻毒后第7天出现病毒血症,持续14～21 d后逐渐消退,仔猪感染PRRSV变异株后,病毒可通过鼻、眼、咽喉分泌物及粪便等排出,其中鼻分泌物排毒最早、排毒时间最长,眼、咽喉分泌物与鼻分泌物、粪便相比排毒较晚、持续时间较短。     

Notoginsenoside R1 protects boar sperm during liquid storage at 17°C

Reactive oxygen species (ROS) damage mammalian sperm during liquid storage. Notoginsenoside R1 (NR1) is a compound isolated from the roots of Panax notoginseng; it has powerful ROS-scavenging activities. This work hypothesized that the antioxidant capacity of NR1 could improve boar sperm quality and fertility during liquid storage. During liquid storage at 17°C, the supplementation of semen extender with NR1 (50 μM) significantly improved sperm motility, membrane integrity and acrosome integrity after 5 days of preservation. NR1 treatment also reduced ROS and lipid peroxidation (LPO) levels at day 5 (p <0.05). Higher glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) levels and sperm–zona pellucida binding capacity were observed in the 50 μM NR1 group than those in the control group at day 7 (p <0.05). Importantly, statistical analysis of the fertility of 200 sows indicated that addition of NR1 to the extender improved the fertility parameters of boar spermatozoa during liquid storage at 17°C (p <0.05). These results demonstrate the practical feasibility of using 50 μM NR1 as an antioxidant in boar extender during liquid storage at 17°C, which is beneficial to both spermatozoa quality and fertility.