【作者】 王杰；

【导师】 李国喜；

【作者基本信息】 河南农业大学 ， 养殖（专业学位）， 2018， 硕士

【摘要】 淅川乌骨鸡是我国著名的地方特色品种,是国内外报道过唯一一种产绿壳蛋的白羽乌骨鸡。经研究发现乌骨鸡由黑色素沉积量与脂肪酸含量能影响肉品质,其中黑色素含量是最重要的影响因素,通过提高黑色素含量能显著增加乌骨鸡营养水平及风味。为深度挖掘淅川乌骨鸡潜在的黑色素价值,通过外源添加剂调控胸肌黑色素沉积量从而提高其营养水平。因此,本试验通过六组不同的日粮酪氨酸添加水平饲喂0～12周龄淅川乌骨鸡,具体分组及添加水平为对照组(0%)、处理组Ⅰ～Ⅴ(0.2%、0.4%、0.6%、0.8%、1.0%)。待12周龄时进行屠宰,测定各组的生长、屠宰性状与肉品质相关指标,再利用转录组测序技术筛选出样本间差异基因,并对差异基因进行GO功能、KEGG通路富集分析。通过生产上表观数据与分子标记相结合,旨在鉴定与黑色素、脂肪酸相关的差异基因,为后续生产高品质淅川乌骨鸡奠定坚实的基础。结果如下:试验一:日粮酪氨酸水平对淅川乌骨鸡生长性能、屠宰性状的影响1、生长性能:体斜长,处理组Ⅴ显著低于处理组Ⅰ、Ⅳ(P<0.05);龙骨长,处理组Ⅴ显著低于其余五组(P<0.05);胫长,处理组Ⅰ显著高于处理组Ⅲ、Ⅴ(P<0.05);胸宽与胸角,处理组Ⅴ显著低于对照组与处理组Ⅰ(P<0.05)。2、屠宰性状:活体重,对照组与处理组Ⅰ显著最高(P<0.05);屠宰率,处理组Ⅳ、Ⅴ显著低于其余四组(P<0.05);腿肌重,处理组Ⅲ、Ⅳ显著低于对照组(P<0.05);而胸肌率与全净膛率在组间无显著差异(P>0.05)。试验二:日粮酪氨酸水平对淅川乌骨鸡胸肌肉品质的影响1、肉品质:腿肌剪切力,处理组Ⅱ显著高于其余四个处理组(p<0.05);胸肌剪切力,处理组Ⅱ、Ⅴ显著高于对照组(p<0.05);但胸肌(45min/24h)与腿肌(45min/24h)的p H值各组之间差异都不显著的(p>0.05)。2、黑色素含量:不同日粮酪氨酸添加水平能显著提高胸肌黑色素沉积量,处理组Ⅱ～Ⅴ胸肌黑色素含量显著高于对照组与处理组Ⅰ(p<0.05),并在酪氨酸添加浓度为0.8%(处理组Ⅳ)时,胸肌黑色素含量最大。3、脂肪酸含量:基于前期黑色素测定试验结果,测定对照组与处理组Ⅳ脂肪酸含量,分别检测出了19种脂肪酸,在饱和脂肪酸中处理组Ⅳ的山嵛酸的含量显著低于对照组(P<0.05),在不饱和脂肪酸中处理组Ⅳ的亚油酸的含量显著低于对照组(P<0.05),其余17种脂肪酸在两组中均没有显著差异(P>0.05)。试验三:日粮酪氨酸水平调控淅川乌骨鸡胸肌肉品质相关基因的鉴定基于前期黑色素测定结果,选择对照组与处理组Ⅳ胸肌组织进行转录组测序。测序结果发现,14935个基因在两样本中表达,其中在两样本中13477个基因共表达,在对照组胸肌中698个基因特异表达,处理组Ⅳ胸肌中760个基因特异表达。最终得到了差异表达基因417个,其中160个基因在处理组Ⅳ上调,257个基因在对照组上调。对差异基因进行GO功能与KEGG富集分析,差异基因共注释到50个GO term和91条KEGG pathway中,并筛选出12条与脂肪酸代谢相关通路,4条黑色素合成相关通路,同时从中发现FAS、ACACB、MITF、TYRP2这四个与脂肪沉积、黑色素合成的有关基因,拟作为后续研究的重点。通过不同日粮酪氨酸水平对12周龄淅川乌骨鸡肉质的影响发现,在适宜的酪氨酸浓度下(0.8%),能显著提高胸肌黑色素的沉积量,并对部分脂肪酸也有显著的影响,随后通过转录测序,筛选鉴定了黑色素与脂肪酸相关的基因与通路。更多还原

【Abstract】 Xichuan Silky is a famous local special breed in China,and was the only kind of white(katabane)feather colour Silkys producing blue shell eggs.Studies showed that melanin deposition and fatty acid content in Silky fowl could affect meat quality,of which the melanin deposition is the most important influence factor,and it can increase significantly the nutritional level and flavor by improving melanin content.In order to dig deeper the potential value of melanin in Xichuan Silky,exogenous additive was used to regulate content of breast muscle melanin and increase its nutritional level.In this paper,Xichuan Silky was fed with six different dietary tyrosine levels at 0-12 weeks,and the specific grouping and addition levels were control group(0%),treatment group I-V(0.2%,0.4%,0.6%,0.8%,1.0%).Slaughtered at 12 weeks,growth traits,slaughter traits and meat quality measured.And the differential genes among the samples were screed using high-throughput transcriptome sequencing,and analyzed with the Go gene function and KEGG pathway enrichment.By combining the apparent data with molecular markers,aim to identify differential genes related to melanin and fatty acid,and establish a solid foundation for high quality Silky fowl.The results of this study are as follows:Study 1: Effect of dietary tyrosine levels on growth traits and slaughter traits of Xichuan Silky1.Growth performance: The body length in treatment V was significantly lower than that in treatmentⅠ,Ⅳ(P<0.05).The keel length in treatment V was significantly lower than that in the remaining five groups(P<0.05).The shank length in treatment Ⅰwas significantly higher than that in treatment Ⅲ,Ⅴ(P<0.05).The breast width and chest angle in treatment V were significantly lower than that in control group and treatment Ⅰ(P<0.05).2.Slaughter traits: The live weight in control group and treatment Ⅰwas the highest significantly(P<0.05).The slaughter rate in treatment Ⅳ,Ⅴwere significantly lower than that in the remaining four groups(p<0.05).The leg muscle weight in treatment Ⅲ,Ⅳ were significantly lower than that in control group(P<0.05).However,there were no significant difference between the breast muscle rate and eviscerated yield rate(P<0.05).Study 2: Effect of dietary tyrosine level on meat quality of Xichuan Silky1.Meat quality: The leg muscle shear force in treatment Ⅱwere significantly higher than that in the remaining four treatment groups(p<0.05).The pectoral muscle shear force in treatment Ⅱ,Ⅴ were significantly higher than that in control group(p<0.05).But the breast and leg muscles p H were no significant difference among all groups(p<0.05).2.Melanin content: It can increase significantly the deposition of melanin in breast muscle by different dietary tyrosine levels.The deposition of melanin in breast muscle in treatment Ⅱ~Ⅴ was significantly higher than that of control group and treatmentⅠ,and it was the largest when tyrosine was added at 0.8%(treatment Ⅳ)(p<0.05).3.Fatty acid content: Based on the results of the previous melanin assay,the fatty acid content in control group and treatment Ⅳwas tested and 19 amino acids were detected.The content of docosanoic acid in treatment Ⅳwas significantly lower than that in control group in saturated fatty acids(P<0.05).The content of linoleic acid in treatment was significantly lower than that in control group in unsaturated Ⅳfatty acid(P<0.05).The other 17 fatty acids were no significant difference in the two groups(P<0.05).Study 3: Identification of genes regulated by dietary tyrosine level which related to meat quality in Xichuan SilkyBased on the results of the previous melanin assay,breast muscle tissue in control group and treatment group IV was used for high-throughput transcriptome sequencing.The results showed that 14935 genes were expressed in two samples,of which 13477 genes were co-expressed in two samples,698 genes were specifically expressed in the control group,and 760 genes were specifically expressed in the treatment Ⅳ.Finally,417 differentially expressed genes were obtained,of which 160 genes were up-regulated in treatment IV and 257 genes were up-regulated in the control group.Differential genes were analyzed by GO function and KEGG enrichment,and annotated to 50 GO term and 91 KEGG pathways.12 pathways related to fatty acid metabolism and 4 pathways related to melanin synthesis were screened.Additionally,FAS,ACACB,MITF and TYRP2 genes related to fat deposition and melanin synthesis were found,and intended to be the focus of follow-up research.更多还原