Association Analysis on MAP3K5 Gene Polymorphism Site with Growth and Feed Efficiency Related Traits in Duroc Pigs

This study was aimed to analyze the association of four SNPs of MAP3K5 gene with growth and feed efficiency related traits in Duroc populations. Four SNPs(Ssc1:30769583 A>C;Ssc1:30781169 A>G;Ssc1:30940839 A>G;Ssc1:30962276 G>A)of MAP3K5 gene in Duroc populations were obtained by porcine SNP60 BeadChip（Illumina). The genotype frequency and allele frequency of four SNPs of MAP3K5 gene were analyzed,the result showed that four SNPs were the low-moderate mutation SNPs.The polymorphism of MAP3K5 gene and its association with feed efficiency related traits in Duroc population were analyzed. The results indicated that CC genotype individuals in Ssc1:30769583 A>C had significant lower RFI（133.08 g/d）than AA genotype individuals（P<0.05);GG genotype individuals in Ssc1:30781169 A>G had significant lower RFI（116.18 g/d）and ADFI（0.23 kg/d）than AG genotype individuals（P<0.05);GG genotype individuals in Ssc1:30940839 A>G had significant lower FCR（0.10%）than AG genotype individuals（P<0.05);AA genotype individual in Ssc1:30962276 G>A had significant lower ADG（0.04 kg/d）than GG genotype individuals（P<0.05). All in all,the results suggested that four SNPs polymorphisms of MAP3K5 gene had the significant impact on RFI, ADFI, FCR and ADG traits in Duroc pigs.     

猪多经济性状的重建研究

本研究的目标是对猪多个经济性状进行性状重建,并对重建性状的遗传参数进行估计。本研究涉及性状重建的原始经济性状包括了生长、胴体和肉质3类共24个性状。性状重建利用主成分分析法,经统计分析后得到4个主成分作为新的重建性状。在对重建性状进行描述性统计处理基础上,进一步利用动物模型和DFREML算法估计了各性状的遗传力,得到第1、2、3和4主成分的遗传力分别为0.87、0.58、0.49和0.56。研究结果表明,通过性状重建不但可以实现多性状的降维处理,而且重建性状的遗传力有提高趋势,性状重建策略有望促进多性状育种的进程。     

高粱替代玉米对育肥猪生长性能、血液生化指标、抗氧化性能和免疫力的影响

本试验旨在研究高粱替代不同水平的玉米对育肥猪生长性能和血液生化指标的影响。选择体重为(48.93±3.01)kg、健康的杜×长×大三元育肥猪160头,随机分为4组,每组4个重复,每个重复10头猪。基础日粮为玉米-豆粕型,根据NRC(2012)配制,对照组饲喂基础日粮,试验组分别用高粱替代30%、65%和100%的玉米,预试期7d,试验期60d。结果表明:与对照组相比,高粱替代部分玉米后对育肥猪的耗料增重比、平均日采食量无显著影响,高粱全部替代玉米后育肥猪平均日增重降低3.4%(P<0.05);用高粱替代65%和100%的玉米对育肥猪血清免疫指标和血液生化指标无显著影响,但抗氧化酶活性提高了32.4%和38.7%(P<0.05),同时还能够降低丙二醛浓度(P<0.05)。综上所述,在本试验条件下,高粱替代玉米可以提高育肥猪血清抗氧化功能,可替代日粮中30%～65%的玉米进行猪育肥生产。     

抑制泛素结合酶改变猪卵母细胞透明带泛素化状态及精-卵结合能力

本研究旨在探究猪卵母细胞体外成熟过程中添加泛素结合酶(E2)抑制剂对卵母细胞透明带蛋白泛素化水平及精-卵结合能力的影响。试验分为6组:对照组、DMSO组、5、10、15和20μmol·L^-1 NSC697923处理组。采用Western blot方法分析体外成熟培养液中添加不同浓度泛素结合酶抑制剂NSC697923对猪卵母细胞透明带泛素化水平表达的影响。通过Hoechst染色检测不同组别的精卵结合能力。结果表明:1)猪卵母细胞体外成熟培养液中,添加10、15和20μmol·L^-1 NSC697923显著降低卵母细胞成熟率(P<0.05),透明带硬化时间(P<0.05)以及精卵结合率(P<0.05)。2)对照组和各处理组的透明带蛋白在61、81、106 ku处发生不同程度的泛素化标记,而添加15和20μmol·L^-1 NSC697923显著地降低透明带蛋白泛素化水平(P<0.05)。综上表明,猪卵母细胞体外成熟过程中泛素结合酶(E2)改变成熟卵母细胞透明带泛素化水平以及精卵结合能力。     

Effects of dietary ramie powder at various levels on growth performance,antioxidative capacity and fatty acid profile of finishing pigs

This study was conducted to evaluate the effects of ramie (Boehmeria nivea, previously known as a fibre crop and also called “China grass”) included in diets on growth performance, antioxidative capacity and muscular fatty acid profile of finishing pigs. A total of 180 Xiangcun Black pigs (initial body weight =70.71 ± 1.21 kg) were randomly allotted to 1 of 5 dietary treatments with six pens of six pigs per pen. The pigs were provided a basal diet or a diet contained 3%, 6%, 9% or 12% of ramie powder during a 50‐day experiment period. The results showed that the inclusion of ramie increased (quadratic, p < 0.05) the average daily gain (ADG) and gain:feed ratio (G:F) with the highest value of ADG and G:F in 3% ramie group, but ramie content in the diet up to 9% reduced the growth performance of the pigs compared with that of 3% ramie group. The activity of serum total superoxide dismutase (SOD) was increased (linear, p < 0.05) by ramie, while content of malondialdehyde was decreased (linear, p < 0.05). As increasing the dietary ramie level, the mRNA expression level of SOD1 was increased quadratically (p < 0.05) in muscle tissues. Moreover, the addition of ramie linearly increased (p < 0.05) polyunsaturated fatty acids content, whereas it linearly reduced (p < 0.05) the lipid indices of atherogenicity (AI) and thrombogenicity (TI) in muscle tissues, and lower values of AI and TI reflect a “healthier” fat composition. The results indicated that ramie in a diet not more than 9% may improve antioxidative capacity with no detrimental impact on growth performance of Chinese native finishing pigs; meanwhile, it could beneficially change the pork fatty acid pattern which has a positive impact on consumer's health.     

The variation in hectolitre weight of wheat grain fed with or without enzyme supplementation influences nutrient digestibility and subsequently affects performance in pigs

A 2 × 2 factorial experiment was conducted to investigate the effect of feeding a wheat‐based diet of two different hectolitre weights (66 vs. 74 kg/hl), achieved through different agronomical conditions, with or without the supplementation of a β‐glucanase and β‐xylanase enzyme mix on young pigs. The parameter categories which were assessed included growth performance, coefficient of apparent total tract digestibility (CATTD), faecal consistency, faecal microbial populations and faecal volatile fatty acid (VFA) concentrations. Sixty‐four pigs (11.6 kg SD 0.97) were assigned to one of four dietary treatments: (T1) low hectolitre weight wheat diet, (T2) low hectolitre weight wheat diet containing 0.1 g/kg β‐glucanase and β‐xylanase enzyme supplement, (T3) high hectolitre weight wheat diet and (T4) high hectolitre weight wheat diet containing 0.1 g/kg β‐glucanase and β‐xylanase enzyme supplement. The inclusion of wheat was 500 g/kg in the diet. The low hectolitre weight grain had a higher level of zearalenone, aflatoxin and ochratoxin contamination compared to the high hectolitre weight grain. The high hectolitre weight wheat had a higher gross energy (GE), crude protein (CP) and lysine contents compared to the low hectolitre weight wheat. Pigs offered the low hectolitre weight diet had a lower average daily gain (ADG) (p < 0.001), a lower gain to feed (G:F) ratio (p < 0.001) and a higher faecal score (more diarrhoea) (p < 0.001) compared to pigs offered the high hectolitre weight. The low hectolitre weight diet had a reduced CATTD (p < 0.05) of nitrogen (N) and gross energy (GE) compared with pigs offered the high hectolitre weight diet. In conclusion, the higher level of mycotoxins and lower content of GE, CP and lysine in the low‐quality wheat reduced ADG and the CATTD of nutrients in pigs offered this diet. The inclusion of a β‐glucanase and β‐xylanase enzyme mix had no effect on growth performance or nutrient digestibility.     

基于测序技术的海南地方猪TLR2基因多态性分析

为了解海南地方猪TLR2基因的多态性,本研究采用PCR法从五指山猪、临高猪和屯昌猪3种海南地方猪的血液中克隆Toll样受体2(TLR2)基因,并进行测序及序列分析。结果显示,3种海南地方猪TLR2基因的扩增长度均为2649bp,编码区长2358bp。3种猪TLR2基因序列的种内比对结果显示,五指山猪种内有7个核苷酸位点存在多态性,2处位于编码区;屯昌猪种内有5个核苷酸位点存在多态性,均在编码区外;临高猪种内有4个核苷酸位点存在多态性,1处位于编码区。种间比对结果显示3种猪有12个核苷酸位点存在多态性,其中3处为错义突变,导致氨基酸改变。同源性分析结果显示,3种猪的TLR2基因序列高度保守,同源性在99.6%~99.9%之间。蛋白质结构预测分析显示,海南猪TLR2基因在876、1454位点呈现的AG突变均引起了其蛋白质二级结构和三级结构的改变,提示可能存在TLR2功能的变化。本研究填补了海南地方猪TLR2基因多态性空白,为深入研究TLR2基因多态性与猪疫病易感性的关系提供基础研究资料。     

深县猪肉质及营养价值分析

本研究选择国外猪种杜洛克和中国地方猪深县猪体重 95 kg 的阉割公猪各 5 头,比较 2 个猪品种背最长肌之间肉质、氨基酸、脂肪酸和微量元素的差异。结果表明:杜洛克猪的肌内水分、肉色、大理石纹、滴水损失、粗蛋白质和脂肪含量低于深县猪(P<0.01);杜洛克猪背最长肌中谷氨酸、天冬氨酸、精氨酸、组氨酸、丝氨酸、脯氨酸、甘氨酸、苏氨酸、半光氨酸、丙氨酸、缬氨酸、苯丙氨酸、异亮氨酸、酪氨酸、亮氨酸、呈味氨基酸总量、必需氨基酸和总氨基酸含量低于深县猪(P<0.01);杜洛克猪背最长肌的饱和脂肪酸含量棕榈酸、豆蔻酸、硬脂酸和花生四烯酸多不饱和脂肪酸亚油酸和亚麻酸低于深县猪(P<0.01);单不饱和脂肪酸棕榈油酸含量低于深县猪(P<0.01),而油酸没有显著性差异;杜洛克猪背最长肌中微量元素钾、锶、铜、锌、硅和铬含量均低于深县猪(P<0.01),镍差异显著(P<0.05)。结果显示,中国地方猪深县猪在肉质及营养价值方面优于瘦肉型的杜洛克猪,为深县猪的品种资源保护和肉产品的开发利用提供依据。     

Genotype and dietary lysine deficiency affect carcass and muscle amino acid composition of pigs growing from 10 to 25 kg body weight

Amino acid (AA) composition of body protein is considered constant although there are evidences that AA pattern in pigs may be altered by different factors. Pigs with different body composition and protein deposition rates—like fatty and lean pigs—may differ in AA composition, with possible consequences on their AA requirements. This work investigates effects of genotype and dietary lysine deficiency on AA composition of carcass and muscles of Iberian and Landrace × Large White pigs. Twenty‐eight barrows (10 kg body weight [BW]), 14 from each breed, were used. They were randomly assigned to two experimental diets according to a factorial arrangement (two breeds × two diets). Diets were isonitrogenous and isoenergetic (200 ± 1 g CP/kg dry matter (DM); 14.7 ± 0.1 MJ ME/kg DM) and with identical chemical composition except for lysine concentration (10.9 and 5.20 g lysine/kg DM, for lysine‐adequate (AL) diet and lysine‐deficient (DL) diet respectively). Pigs were individually housed, and daily feed allowance was adjusted on a weekly basis according to BW. Pigs were slaughtered at 25 kg BW. Isoleucine, valine and phenylalanine concentration were higher in carcass protein of Iberian pigs (p < .01). In longissimus muscle, higher concentration of arginine, isoleucine, phenylalanine, lysine and valine (p < .001–p < .05), and lower of methionine (p < .001) were detected in Iberian pigs, whereas phenylalanine, leucine, lysine, threonine and methionine concentration decreased and arginine increased (p < .001–p < .05) when pigs were fed DL diet. Genotype and lysine deficiency effects were moderate in the AA composition of protein of biceps femoris muscle. The results show that AA proportions in protein of carcass and longissimus muscle can be influenced by pig genotype and conditions of lysine shortage. The biceps femoris muscle, with different functional and metabolic properties, shows more constant AA composition than longissimus, which seem to prevail independent from genotype or nutritional challenges.     

Significance testing and genomic inflation factor using high‐density genotypes or whole‐genome sequence data

Significance testing for genome‐wide association study (GWAS) with increasing SNP density up to whole‐genome sequence data (WGS) is not straightforward, because of strong LD between SNP and population stratification. Therefore, the objective of this study was to investigate genomic control and different significance testing procedures using data from a commercial pig breeding scheme. A GWAS was performed in GCTA with data of 4,964 Large White pigs using medium density, high density or imputed whole‐genome sequence data, fitting a genomic relationship matrix based on a leave‐one–chromosome‐out approach to account for population structure. Subsequently, genomic inflation factors were assessed on whole‐genome level and the chromosome level. To establish a significance threshold, permutation testing, Bonferroni corrections using either the total number of SNPs or the number of independent chromosome fragments, and false discovery rates (FDR) using either the Benjamini–Hochberg procedure or the Benjamini and Yekutieli procedure were evaluated. We found that genomic inflation factors did not differ between different density genotypes but do differ between chromosomes. Also, the leave‐one‐chromosome‐out approach for GWAS or using the pedigree relationships did not account appropriately for population stratification and gave strong genomic inflation. Regarding different procedures for significance testing, when the aim is to find QTL regions that are associated with a trait of interest, we recommend applying the FDR following the Benjamini and Yekutieli approach to establish a significance threshold that is adjusted for multiple testing. When the aim is to pinpoint a specific mutation, the more conservative Bonferroni correction based on the total number of SNPs is more appropriate, till an appropriate method is established to adjust for the number of independent tests.