Interpopulation and intrapopulation maternal lineage genetics of the Lanyu pig (Sus scrofa) by analysis of mitochondrial cytochrome b and control region sequences

The Lanyu pig is an indigenous breed from the Lanyu Islet, which is southeast of Taiwan. Two herds of Lanyu pigs were introduced from the Lanyu Islet into Taiwan in 1975 and 1980. The current population of conserved Lanyu pigs consists of only 44 animals with unknown genetic lineage. The Lanyu pig possesses a distinct maternal genetic lineage remote from Asian and European pigs. The present study aimed to understand the phylogenetic relationship among conserved Lanyu, Asian, and European type pigs based on the cytochrome b coding gene, to ascertain the maternal lineage and genetic diversity within the conserved Lanyu pigs, and to address whether genetic introgression from exotic or Formosan wild pigs had occurred in the conserved Lanyu pigs. Entire mitochondrial genomes of both types of Lanyu pig comprised 2 ribosomal RNA, 22 transfer RNA, and 13 protein-coding genes. Only 2 haplotypes of the mitochondrial DNA (mtDNA) control region and cytochrome b were identified in the conserved Lanyu pig herds. When maximum likelihood trees were constructed, the Type I Lanyu mitochondrial genes formed a unique clade with a large pairwise distance of both cytochrome b and the control region from Asian and European type breeds, Formosan wild pigs, and exotic breeds. Significant loss of genetic diversity of mtDNA within the conserved Lanyu pigs was demonstrated by low haplotype and nucleotide diversities, supported by Fu and Li's D* neutrality test (1.44055; P < 0.05). The mtDNA control region sequences of extant pigs in the Lanyu Islet, however, showed high haplotype and nucleotide diversity, and clustered with exotic pigs. These results indicate no maternal lineage mtD-NA gene introgression from Formosan wild pigs and introduced exotic pigs to conserved Type I Lanyu pigs, and a severe loss of heterozygosity of mtDNA in conserved Lanyu pigs. The remaining extant pigs on the Lanyu Islet have been introgressed with exotic breeds. Strategies for future conservation of native Lanyu pigs are now even more urgent and important.     

Trichostatin A and nuclear reprogramming of cloned rabbit embryos

To investigate the influence of histone deacetylases on nuclear reprogramming after nuclear transfer, we treated the cloned embryos with a histone deacetylase inhibitor, Trichostatin A (TSA). In the present study, global changes in acetylation of histone H3-lysine 14, histone H4-lysine 12, and histone H4-lysine 5 were studied in rabbit in vivo fertilized embryos, somatic cell nuclear transfer (SCNT) embryos, and TSA-treated SCNT embryos. From the pronuclear to the morula stage, the deacetylation-reacetylation changes in acetylation of histone H3-lysine 14 and histone H4-lysine 12 occurred in both fertilized embryos and TSA-treated cloned embryos; however, the distribution pattern in untreated cloned embryos failed to display such changes. More interesting, the signal of acetylation of histone H4-lysine 12 in cloned embryos was detected in both the inner cell mass and the trophectoderm, whereas TSA-treated cloned embryos showed the same staining pattern as fertilized embryos and the staining was limited to the inner cell mass. The histone acetylation pattern of TSA-treated SCNT embryos appeared to be more similar to that of normal embryos, indicating that TSA could improve nuclear reprogramming after nuclear transfer.     

Baggs ewes adapt to maternal undernutrition and maintain conceptus growth by maintaining fetal plasma concentrations of amino acids

Adequate delivery of AA is essential for normal fetal growth and development. Recently, we reported that when ewes from the University of Wyoming flock (farm flock with adequate nutrition) were fed 50% (nutrient-restricted) or 100% (control-fed) of the NRC-recommended nutrient requirements between d 28 and 78 of gestation, fetal weights as well as concentrations of most AA in maternal and fetal blood were substantially reduced in nutrient-restricted vs. control-fed pregnancies. The current study utilized Baggs ewes, which were selected under a markedly different production system (range flock with limited nutrition), to test the hypothesis that adaptation of ewes to nutritional and environmental changes may alter placental efficiency and conceptus nutrient availability in the face of maternal nutrient restriction. Baggs ewes received 50 or 100% of the NRC nutrient requirements between d 28 and 78 of pregnancy. On d 78, maternal uterine arterial and fetal umbilical venous blood samples were obtained, and the ewes were euthanized. Amino acids and their metabolites (ammonia, urea, and polyamines) in plasma were analyzed using enzymatic and HPLC methods. The results showed that maternal plasma concentrations of 9 AA (Asp, Ile, Leu, Lys, Orn, Phe, Thr, Trp, and Val) as well as maternal and fetal plasma concentrations of ammonia and urea were reduced (P < 0.05) in nutrient-restricted compared with control-fed Baggs ewes. However, fetal plasma concentrations of all AA and polyamines did not differ (P = 0.842) between the 2 groups of ewes. Collectively, these findings suggest that Baggs ewes, by adapting to the harsh conditions and limited nutrition under which they were selected, were able to maintain fetal concentrations of AA in the face of a maternal nutrient restriction through augmenting placental efficiency.     

畜禽良种繁育体系建设之我见

畜禽良种繁育体系和饲料生产体系是进行畜牧业生产的两大支撑体系.这两大支撑体系的建设,对推进我国畜牧业经济持续、健康、协调发展具有重大的作用.本文将对我国畜禽良种繁育体系建设的有关问题提出一些意见和建议,希望能起到抛砖引玉的作用.     

猪营养与肠道健康

肠道不仅在消化吸收营养物质过程中发挥着重要作用,而且是机体的重要免疫屏障,肠道健康水平决定着动物的健康状况。肠道结构的完整性和功能的正常发挥均需要通过获取各种营养物质来维持,因此,日粮中各种营养成分对肠道健康十分重要。本文综述了近年关于猪肠道营养成分对肠道健康影响的研究进展。     

当前美国蛋鸡疾病状况一瞥

<正>美国当前蛋鸡业面临的主要疾病包括大肠杆菌病、十二指肠局灶性坏死(FDN)、软骨病、传染性喉气管炎(ILT)和马立克氏病(MD)。当前,美国蛋鸡业正处于鸡群保健和疫病相对平静的一     

不同单酶制剂混合检测对比研究

试验以木聚糖酶、纤维素酶、淀粉酶和酸性蛋白酶为对象,首先研究了酸性蛋白酶分别和其他3种单酶进行混合后酶活测定值变化情况,结果表明,酸性蛋白酶对其他3种单酶的检测结果没有影响;试验第二部分研究了4种单酶整体混合在一起后各单酶测定值的变化情况,结果表明,木聚糖酶测定值出现很大偏高,其他3种单酶测定结果未出现显著偏差;进行进一步论证试验表明,淀粉酶可能是使木聚糖酶测定结果偏高的原因。     

水合硅铝酸钠钙(脱霉素)对肉仔鸡Zn、Mn、VA、VB_2利用的影响

本研究通过3个试验评估水合硅铝酸钠钙(HSCAS,一种层状硅铝酸盐)对肉仔鸡Zn、Mn、VA和VB2利用的影响。试验1中,玉米-豆粕型日粮中添加0.5%或1.0%HSCAS对总胫骨Mn含量和肝脏VA浓度均没有影响(P0.05),总胫骨Zn含量有轻微的下降,但是与添加HSCAS的水平是呈线性关系的(P0.05);在试验2(0.5%HSCAS)和试验3(1.0%HSCAS)中,向不含VB2的纯氨基酸日粮中添加梯度浓度的VB2(0、0.6和1.2mg/kg日粮),VB2的利用率并没有受到0.5%或1.0%HSCAS的影响。本研究结果表明,日粮中添加0.5%或1.0%HSCAS不会削弱肉仔鸡Mn、VA或VB2的利用,但是Zn的利用率会有轻微的下降。     

重新认识农区山羊放牧饲养

文章从山羊养殖历史、生物学特性、自然社会、经济效益、生态环保、市场消费及国外养殖进展等方面进行研究,认为我国南方农区山羊饲养应回归放牧养羊,可以实现社会生态经济的可持续发展。同时提出放牧养殖的标准化建设思路。     

猪圆环病毒2型和猪瘟病毒抗体检测与分析

目的检测临汾市某县猪圆环病毒2型(PCV2)和猪瘟病毒(CSFV)的抗体水平.方法分别从该县的企业、散户、大户的猪只中采集血清186份,应用ELISA方法检测抗体水平.结果 PCV2抗体阳性率平均为83.33%,CSFV抗体阳性率平均为54.83%.结论该县猪圆环病毒2型感染严重,猪瘟疫苗免疫抗体水平偏低,与猪瘟疫苗使用不当、猪圆环病毒2型感染存在一定关系.