Supplementation of different fat sources affects growth performance and carcass composition of finishing pigs

Background: There are various fat sources with different energy values and fatty acid compositions that may affect growth performance and carcass composition of grow-finishing pigs. A higher net energy was recently reported in choice white grease compared with soybean oil. Therefore, two experiments were conducted to determine whether practical responses confirm that difference between choice white grease and soybean oil, and to extend the observations to other fat sources.Results: In Exp. 1, pigs fed fats had lower(P < 0.05) average daily feed intake in phase II and overall period,greater(P < 0.05) gain:feed in phase I, phase II, and overall period than pigs fed the control diet. Pigs fed fats tended(P = 0.057) to have thicker backfat depth at the last rib than those fed control. Pigs fed 6% fats had greater(P < 0.01) gain:feed in phase II and overall period than pigs fed 3% fats. During phase I, pigs fed choice white grease grew faster(P < 0.05) than pigs fed soybean oil. In Exp. 2, pigs fed dietary fats(soybean oil, choice white grease, animal-vegetable blend, palm oil, or tallow) had greater(P < 0.01) gain:feed in each phase and overall period, greater(P < 0.01) average daily gain in phase I, but lower(P < 0.01) average daily feed intake in phase II an overall than pigs fed the control diets. The choice white grease also increased(P < 0.05) average daily gain during phase I compared with soybean oil. Pigs fed palm oil had thicker(P < 0.05) backfat depth at the 10 thrib than those fed soybean oil, animal-vegetable blend, or tallow.Conclusions: Inclusion of 6% dietary fat improved feed efficiency of finishing pigs, while different fats produced different practical results that may be consistent with their different energy values. Results from the early stage indicate that dietary fats with relatively more saturated fatty acids may provide greater energy than those with relatively more unsaturated fatty acids for growing pigs.

Surplus dietary isoleucine intake enhanced monounsaturated fatty acid synthesis and fat accumulation in skeletal muscle of finishing pigs

Background: Isoleucine(Ile) has been implicated in the regulation of energy homeostasis and adipogenesis.However,the impact of surplus dietary Ile intake on muscle lipogenesis remains unknown.The present study aimed to investigate the impact of dietary supplementation of extra-Ile on lipogenesis,fatty acid profile and lipid accumulation in skeletal muscle in finishing pigs.Methods: Forty-eight barrows with initial body weight of 77.0 ± 0.1 kg were allotted to one of two groups and fed diets containing 0.39%,0.53% standardized ileal digestible(SID) Ile with six replicates per treatment and four pigs per replicate for 30 d.Results: Dietary Ile intake significantly improved the intramuscular fat(IMF) content and monounsaturated fatty acid(MUFA) concentration in the skeletal muscle(P < 0.05),and decreased the drip loss and shear force(P < 0.05) without influencing the growth performance of pigs(P > 0.05).Moreover,the phosphorylation of adenosine monophosphate activated protein kinase α(AMPKα) and acetyl coenzyme A carboxylase(ACC) proteins that monitor lipid metabolism were decreased in skeletal muscle of pigs offered extra-Ile diet(P < 0.05).The mRNA expression of adipose-specific genes adipocyte determination and differentiation factor 1(ADD1),fatty acid synthase(FAS),and stearoyl-CoA desaturase(SCD) were upregulated and the activity of SCD was increased as well(P < 0.05).Conclusions: Surplus dietary Ile intake could increase IMF accumulation and MUFA synthesis in skeletal muscle through depressing the phosphorylation of AMPKα-ACC and stimulating the expression and activity of SCD,and increasing the capability of lipogenesis in skeletal muscle.

Effects of dietary fiber content and different fiber-rich ingredients on endogenous loss of fat and fatty acids in growing pigs

Background: Determination of the endogenous loss of fat(ELF) is used to adjust for the estimation of true total tract digestibility(TTTD) of fat in diets and ingredients.Any factor which affected ELF may further affect the digestibility of fat,including sources and concentrations of fat and fiber in the diet.There are some reports of determining the ELF using regression methods based on different levels of fat intake,while reports on effects of dietary fiber content and different fiber-rich ingredients in pig diets on ELF are very limited.Therefore,the objective of this study was to determine the effects of dietary fiber content and different fiber-rich ingredients on endogenous losses of fat and fatty acids at the end of ileum and throughout the entire intestinal tract in growing pigs.Methods: In Exp.1,the effect of fiber content on endogenous loss of fat was determined using six growing pigs(Duroc × Landrace × Yorkshire;27.6 ± 2.4 kg),fitted with a T-cannula at the end of ileum.The experimental design was a 6 × 6 complete Latin square design with six periods of feeding and six diets.The six experimental fat-free diets were formulated to include graded levels of neutral detergent fiber(NDF)(0,40,80,120,160 and 200 g/kg) and soybean hull(SH) was the only fiber source,providing 0,75,150,225,300 and 375 g/kg,respectively.Chromic oxide was included at4 g/kg in all diets as an indigestible marker.In Exp.2,six crossbred growing barrows(27.6 ± 1.6 kg) were used and the experimental design was the same as for Exp.1.The six fat-free diets were formulated to include six common fiber-rich ingredients and the concentration of NDF was 100 g/kg.The six fiber-rich ingredients were defatted rice bran(DRB),sugar beet pulp(SBP),rice hull(RH),corn germ meal(CGM),SH and wheat bran(WB) and they were fed at represented250,270,145,250,170 and 280 g/kg in the diet,respectively.Results: In Exp.1,the endogenous loss of fatty acids profile did not change as dietary NDF increased in growing pigs.The endogenous losses of fat,C16:0,C18:0,C18:1,C18:2,total unsaturated fatty acids(UFA) and total saturated fatty acids(SFA) in growing pigs at the end of ileum and throughout the entire intestinal tract increased linearly as NDF content of diets increased.The endogenous losses of fat,as well as C16:0 and C18:0 throughout the entire intestinal tract also increased quadratically as NDF content of diets increased.The ELF increased from 0.71 to 3.14 g/kg of dry matter intake(DMI) and 0.56 to 8.21 g/kg DMI at the end of ileum and throughout the entire intestinal tract in growing pigs,respectively.The ELF occurred in the hindgut except for the growing pigs fed 0 and 4% NDF in their diets.The endogenous losses of C16:0 and UFA occurred primarily in the upper regions of the gut and the greatest endogenous losses of C18:0 occurred in the hindgut.The endogenous losses of fat,individual SFA and total SFA throughout the entire intestinal tract were much greater than that at the end of ileum.However,the endogenous losses of individual UFA and total UFA were less throughout the intestinal tract than at the end of ileum.In Exp.2,the endogenous losses of fat at the end of ileum were greater in growing pigs fed CGM or WB diets.The endogenous loss of fatty acids profile changed to a slight degree at the end of ileum that the endogenous loss of UFA(particularly C18:1 and C18:2) in growing pigs fed CGM or WB diets were greater(P < 0.01) than that for the other four diets.The greatest(P < 0.01) endogenous loss of SFA(particularly C18:0) was in growing pigs fed the RH diet.The endogenous losses of fat,C16:0,C18:0 and SFA over the entire intestinal tract were much greater in growing pigs fed CGM or WB diets,whereas the lowest values were in growing pigs fed DRB diet.The ELF at the end of ileum in growing pigs fed CGM or WB diets were 3.50 or 4.17 g/kg DMI,respectively,and the ELF over the entire intestinal tract was 7.23 or 7.38 g/kg DMI.The contribution in percentage of ELF in the upper gut was greater than that in the hindgut of growing pigs fed DRB and RH diets,while the ELF in the upper gut and hindgut were equal in growing pigs fed SBP,CGM and WB diets.On the whole,the endogenous losses of C18:1 and C18:2 throughout the entire intestinal tract in growing pigs fed the six fiber-rich ingredients diets were less than losses at the end of ileum,whereas the endogenous loss of fat,C16:0,C18:0 and SFA were greater throughout the intestinal tract than at the end of ileum.Conclusion: The profile of loss in endogenous fatty acids did not change as dietary NDF increased in growing pigs and the endogenous losses of fatty acids(C16:0,C18:0,C18:1 and C18:2) fat,UFA and SFA increased linearly as NDF content increased in the diets of pigs.The endogenous losses of fat or fatty acids at the end of ileum were greater in growing pigs fed RH,CGM or WB diets.The endogenous losses of fat,fatty acids(C16:0 and C18:0) and SFA were greater over the entire intestinal tract in pigs fed CGM or WB diet,while these values were the lowest in growing pigs fed the DRB diet.The contribution in percentage losses of fat in the upper gut were greater than in the hindgut of growing pigs fed DRB and RH diets,while the contribution of losses of fat in the upper gut and hindgut were equal in growing pigs fed SBP,CGM and WB diets.In addition,the endogenous loss of individual or total UFA was less over the entire intestinal tract of growing pigs fed fiber diets than that at the end of ileum,and the greatest endogenous losses of fat,individual or total SFA were over the entire intestinal tract.Therefore,differences in fiber content and the nature of fiber-rich ingredients in diets of pigs have different effects to the endogenous losses of fat or fatty acids.Considering the requirement of fat or fatty acids of pigs,careful attention must be paid that the endogenous losses of fat and fatty acids when fiber ingredients are used in diets of pigs.

基于大规模RNA-seq数据绘制猪RNA编辑图谱的研究

【目的】A-to-I RNA编辑是一种由ADAR酶家族介导的共转录/转录后修饰,系统绘制猪的RNA编辑图谱,为猪的分子育种提供候选靶标。【方法】收集16种猪组织的3461个RNA-seq数据,采用生物信息学方法检测猪RNA编辑位点。【结果】共检测到130989个RNA编辑位点,其中,A-to-I RNA编辑位点有124208个。A-to-I RNA编辑位点特征分析表明,98.2%的位点位于重复区域,且主要位于猪特异性的SINE反转录转座子区域的PRE-1/Pre0_SS元件内。只有12.3%的A-to-I RNA编辑位点具有编码意功能。最后,本研究分析了7种组织(脂肪、大脑、大肠、小肠、骨骼肌、肝和肺)的特异性A-to-I RNA编辑位点,脂肪组织特异性位点宿主基因的功能富集分析表明,这些基因在与细胞脂质代谢过程、脂质代谢过程、硫酯代谢过程等相关的信号通路中富集。在这些通路中,与脂肪沉积相关的基因有PDK1、ACSL1和PDE3B等。【结论】绘制了猪的RNA编辑位点图谱,为猪的分子育种提供了候选靶点。

宁乡猪不同发育阶段肌内脂肪沉积差异表达基因及其调控通路分析

【目的】分析不同日龄宁乡猪背最长肌组织mRNA表达谱,筛选发育过程中与脂肪沉积相关的差异表达基因及其所参与的信号通路,并确定部分关键基因在肌内脂肪发育过程中的表达特征。【方法】选取30(D30)和250(D250)日龄宁乡猪各3头,采集背最长肌组织样品提取总RNA进行转录组测序,对测序数据进行比对和处理,筛选参与脂质代谢的差异表达基因进行GO功能、KEGG通路及蛋白互作分析,并随机选取6个差异表达基因进行实时荧光定量PCR验证。【结果】共筛选出30个与脂质代谢相关的差异表达基因,其中9个上调,21个下调。差异表达基因主要富集在脂肪酸氧化、长链脂肪酸代谢等生物过程,线粒体、细胞器膜等细胞组分,酰甘油O-酰基转移酶活性、氧化还原酶活性等分子功能;参与了脂肪酸降解、甘油酯代谢、PPAR等信号通路。蛋白互作分析筛选出ACSL 1、ACAA 2、HADHB、LIPG、GPCPD 1、ALDH 2等关键蛋白基因处于核心位置,通过其mRNA表达量不同参与脂肪沉积调控。ACSL 1、CPT 1 A等6个基因的实时荧光定量PCR验证结果与转录组测序结果一致。【结论】ACSL 1、ACAA 2、HADHB、LIPG、GPCPD 1、ALDH 2等作为核心基因参与宁乡猪肌内脂肪调控,并通过脂肪酸降解、甘油酯代谢等信号通路发挥调控作用。本研究结果为进一步研究猪肌内脂肪沉积相关基因的分子调控机制提供了理论参考。

益生菌调控猪脂质代谢的研究进展

益生菌(Probiotics)是一类对机体有益的活性微生物,猪体内脂肪易过度沉积,会导致其瘦肉率降低,使猪的生长性能和饲料利用率受到影响。益生菌能够通过调节肠道菌群、抑制有害菌生长、促进营养物质吸收利用等方式来调控机体脂质代谢,并在治疗脂质代谢疾病方面具有巨大潜力。本文对益生菌调节肠道菌群及其代谢产物调控脂质代谢的研究进展进行了综述,为益生菌的进一步应用及对猪脂肪代谢相关疾病的诊治提供参考。

基于计算机视觉技术的猪肌内脂肪含量和眼肌面积测定系统的研发

旨在开发基于计算机视觉技术的猪肉质图像快速鉴别方法,为解决猪肉质传统测定方法缺陷和构建猪肉质快速测定系统奠定技术基础。本研究采用canny边缘检测算法、归一化、伽马校正、自适应直方图均衡化和阈值化等方法进行图像处理,利用二维信息模拟了猪背最长肌的三维模型,开发了基于图像的猪肌内脂肪含量计算机视觉测定方法。利用人工描绘和计算机视觉轮廓搜寻技术开发了基于图像处理的眼肌面积识别方法。利用Open CV和C++实现各方法的底层算法程序,研发了一套猪肌内脂肪含量和眼肌面积的测定系统,并利用250头不同品种的试验猪进行了应用测试。测试结果显示,肌内脂肪含量检测模块能够快速实现肌内脂肪图形信息的提取与预测,单个样品检测时间平均不超过2 min,准确性可达0.54,且测定离散系数为0.062,具有较强的稳定性。眼肌面积与背膘厚检测模块能够通过人工与计算机结合的方式快速测定眼肌面积和背膘厚。本研究建立的检测方法和软件系统能够实现猪肌内脂肪含量、背膘厚和眼肌面积的快速检测。

猪FATP1基因5'调控区多态性及其与脂肪性状的相关分析

脂肪酸转运蛋白1(Fatty acid transport protein 1,FATP1)是脂肪酸转运蛋白家族(FATPs)的一员,具有促进脂肪细胞吸收利用长链和极长链脂肪酸的功能,在脂肪沉积过程中发挥着重要的作用。采用直接测序法寻找FATP1基因5'调控区+64～-723 bp片段的单核苷酸多态性,在-586 bp处发现了一个T→C突变SNP(单核苷酸多态性)座位,利用PCR-RFLP的方法检测它在3个试验猪群体中的基因型,发现该座位在皮特兰和金皮F2代猪群中存在多态性,而在金华猪中仅表现为FATP1g-586TFATP1g-586T基因型。建立混合模型方程组分析该座位对188头金皮F2代猪脂肪性状的效应,结果显示,猪FATP1基因第-586座位的不同基因型与肩背膘厚、6～7肋背膘厚、最后一根肋骨处背膘厚、平均背膘厚和板油重显著相关(P<0.05),表明FATP1基因5'调控区的第-586位上的T→C突变对猪脂肪沉积有一定的影响。

转Fat-1基因猪外源基因遗传稳定性分析

测定转Fat-1基因猪外源基因遗传稳定性,为转基因猪育种选择优质新材料提供基础数据。采用PCR和Southern印迹杂交方法对转Fat-1基因传代生产仔猪进行检测,了解Fat-1基因在猪基因组中的整合情况,统计传代猪转基因阳性比率,与自然基因单等位基因正常遗传比率进行差异显著性分析。结果显示,F2代传代仔猪Fat-1基因阳性比率为57.14%,F3代传代仔猪阳性比率为46.67%。F1代公猪外源Fat-1基因是1拷贝基因,传代配种母猪使用非转基因母猪,仔猪阳性比率与自然基因单等位基因正常遗传比率(50%)差异不显著。Fat-1基因在猪育种传代过程中遗传力没有下降,转Fat-1基因公猪能够稳定遗传生产后代猪。

小型猪2型糖尿病模型的部分血清炎性因子变化

目的动态观察小型猪2型糖尿病(T2DM)模型血清中炎性因子水平,为2型糖尿病研究提供参考资料。方法将10头巴马小型猪随机分为对照组(Control)和模型组(DM),对照组以常规饲料喂养,模型组以高脂饮食联合静脉注射链脲佐菌素(STZ)建立小型猪2型糖尿病模型。实验为期9个月,每月检测动物空腹血糖与胰岛素水平,每3个月检测一次糖耐量。采用ELISA试剂盒检测第0、3、6、9个月动物血清中的11种炎性因子水平。结果在高脂饮食诱导3个月后注射STZ,模型组空腹血糖显著升高(P<0.05),糖耐量严重受损,发生了胰岛素抵抗。ELISA结果显示,模型组与对照组动物血清中11种炎性因子水平在前3个月并无特别大的变化,且两组对比无统计学意义。在T2DM发病后,模型组血小板衍生生长因子-BB(PDGF-BB)和肿瘤坏死因子α(TNF-α)的表达水平升高并显著高于对照组(PDGF-BB,第6个月P<0.05;PDGF-BB、TNF-α,第9个月P<0.05),模型组白细胞介素-6(IL-6)的表达水平随着时间的增加逐渐升高,在第9个月的表达水平显著高于第0、3个月(P<0.05),但是与对照组对比并无显著性差异。结论采用高脂饲料联合低剂量STZ成功建立了小型猪2型糖尿病模型。单纯高脂饮食未对小型猪血清炎性因子水平造成明显影响,在T2DM发病后PDGF-BB和TNF-α在血清中的表达水平升高且显著高于正常动物。

不同粒度高粱替代玉米对饲料加工特性和肥猪生长性能的影响

文章旨在探究不同粒度高粱替代玉米对饲料加工特性和肥猪生长性能的影响。试验将120只体重相近、健康的杜×长×大三元杂交育肥猪随机分为6组,即对照组(基础日粮)、试验组(高粱替代100%玉米,筛片孔径:1.5/2.0 mm、2.0/2.0 mm、2.0/2.5 mm、2.5/2.5 mm、2.5/3.0 mm)。每组5个重复,每个重复4头猪,公母各50%,采用公母混养圈养方式饲养90 d。结果表明,随着筛片孔径的增加,饲料的几何平均粒径、颗粒硬度随之增加,耐久性随之下降。除个别组间比较无显著性差异外(P> 0.05),其他组间比较均存在显著性差异(P <0.05);2.5/2.5 mm组的末重[(122.76±7.14)kg]、平均日增重[(0.84±0.06)kg]均最高,与其他组比较均存在显著差异(P <0.05);随着筛片孔径的增加,除2.5/2.5 mm组外,猪养分干物质表观消化率随之降低,除对照组与2.0/2.0 mm组间比较无显著差异外(P> 0.05),其他组间比较均存在显著差异(P <0.05);随着筛片孔径的增加,猪养分粗蛋白质表观消化率呈不规律变化。结论 :用高粱替代玉米,对饲料加工特性影响显著,而对肥猪生长性能无显著影响,且随着高粱粉碎粒度的增加,饲料加工特性及肥猪的生长性能均发生显著改变。

猪肌内脂肪沉积的影响因素及非编码RNA对其调控的研究进展

肌内脂肪(intramuscular fat,IMF)俗称“大理石纹”,是猪肉脂肪组织的重要组成部分,可以改善肉的嫩度、多汁性,提升肉的风味,是评价猪肉品质的重要指标。IMF主要分布在肌纤维或肌纤维束间,由三酰甘油、磷脂和胆固醇组成,受遗传、营养、环境等因素的影响。文章对影响猪IMF沉积的主要因素及非编码RNA(non-coding RNA,ncRNA),包括微小RNA(microRNA,miRNA)、长链非编码RNA(long non-coding RNA,lncRNA)和环状RNA(circular RNA,circRNA)]在猪IMF沉积中的作用进行综述,旨在为深入研究猪脂肪沉积的分子机制提供理论基础。

转hFat-Ⅰ基因猪的繁殖性能及生长发育测定

为了探讨富含ω-3的转脂肪酸去饱和酶(Fat-Ⅰ)基因猪育种价值,试验选取转人源化Fat-Ⅰ(hFat-Ⅰ)基因阳性公猪和非转基因公猪各3头作为父本,通过人工授精方式分别与18头非转基因母猪配种测定其繁殖性能,并对转hFat-Ⅰ基因阳性猪和非转基因猪不同时期的生长发育情况进行测定和比较。结果表明:转hFat-Ⅰ基因猪和非转基因猪繁殖性能差异不显著(P>0. 05);转hFat-Ⅰ基因猪和非转基因猪0,25,32,64,110日龄的体重以及各生长阶段(0~25日龄、26~32日龄、33~64日龄)的日增重差异均不显著(P>0. 05)。说明外源hFat-Ⅰ基因对转基因猪的繁殖性能及生长发育无显著影响。

Dietary supplementation with a high dose of daidzein enhances the antioxidant capacity in swine muscle but experts pro-oxidant function in liver and fat tissues

Background： Although isoflavones are natural dietary antioxidants, they may have toxicological effects. This study aimed to evaluate the redox system in tissues of finishing pigs by supplementation with high dose of daidzein（640 mg/kg）.Results： The supplementation of high dose of daidzein for 64 d increased the activity of superoxide dismutase and total antioxidant capacity in longissimus muscle but down-regulated the expression of reactive oxygen species（ROS）-producing enzyme NADPH oxidase-2 and cyclooxygenase-2. In contrast, high-level supplementation with daidzein exerted pro-oxidant changes in back fat, abdominal fat, liver, and plasma, as reflected by increased contents of malondialdehyde, a lipid peroxidation product, in these tissues. Furthermore, daidzein supplementation resulted in higher expression of ROS-producing enzymes, including NADPH oxidase-1 and cyclooxygenase-1in liver, 5-lipoxygenase（5-LOX） in backfat and NADPH oxidase-2 both in abdominal fat and backfat. The supplementation of daidzein did not affect meat quality parameters in longissimus muscle, including marbling score,eye muscle areas, intramuscular fat, shear force, drip loss, p H and meat color.Conclusions： This experiment suggests that dietary supplementation of finishing pigs with daidzein at a high dose level improves redox status in muscle but exerts pro-oxidant effect in liver and fat tissues.

大型迪庆藏猪不同生长阶段腹脂代谢功能基因筛选及其调控网络分析

[目的]筛选大型迪庆藏猪不同生长阶段腹脂代谢差异的功能基因并解析其调控网络。[方法]选择胎次相同、出生日期及体质量相近的大型迪庆藏猪36头,随机分为3组进行育肥试验,分别在体质量达40、80和120 kg屠宰,每组采集3头猪的腹脂进行转录组测序,测序数据经短时间序列表达模式(STEM)趋势分析、功能富集分析和互作网络分析。[结果]40 kg vs 80 kg、80 kg vs 120 kg和40 kg vs 120 kg分别筛选到1517、486和1752个显著差异基因;差异基因STEM分析显示:模块4和1的基因先显著下调后基本不变,模块15、12和11的基因随体质量增加而显著上调,模块0的基因随体质量增加而显著下调;WNT10B、CPT1B和C5AR2位于模块4和1的基因网络核心,PLA2G7、WWTR1、SPP1、SERPINE1和PTPN11位于模块15、12和11的基因网络核心,ADIPOQ、CH25H和IL10位于模块0的基因网络核心;WNT10B和CPT1B等11个基因的qPCR验证结果与转录组测序结果一致。[结论]WNT10B和PTPN11等11个核心基因以协作方式参与大型迪庆藏猪腹膜脂肪代谢调控,结果可为迪庆藏猪的遗传改良提供参考。

影响宿主脂肪沉积的肠道微生物类别及其作用机理研究

猪体内脂肪沉积受遗传、饲粮、饲养管理和肠道微生物等多种因素的影响。脂肪沉积性状是重要的经济性状,过多的脂肪沉积影响胴体品质和饲料利用率。越来越多的研究表明,肠道微生物在宿主脂肪沉积中起重要作用。本文概述了猪肠道微生物的组成情况,在此基础上系统综述了已鉴别的影响猪脂肪沉积的肠道微生物种类,归纳了肠道菌群影响宿主脂肪沉积的可能机理,并根据国内外研究进展,总结了通过调控肠道微生物组成改善宿主脂肪沉积的方法,并展望将来的研究方向,旨在为将来通过调控肠道微生物来减少猪体内脂肪沉积、提高瘦肉率等提供参考。

大型迪庆藏猪不同生长阶段背脂与腹脂脂质代谢差异基因及调控网络分析

旨在筛选大型迪庆藏猪不同生长阶段、不同部位脂质代谢差异的关键基因。本研究选择胎次相同、出生日期相近、体重10 kg左右的大型迪庆藏猪36头,随机分为3组,相同条件育肥,分别在平均体重达40、80和120 kg时屠宰,测定胴体性能,每组采集3头猪的背脂和腹脂进行高通量转录组测序,测序数据经拼接、比对,筛选与脂质代谢相关的显著差异基因并进行GO、KEGG分析、基因互作网络分析。结果表明,40、80和120 kg大型迪庆藏猪腹脂vs.背脂分别筛到486、765和339个差异表达显著基因,随机挑选的EGR2、SOD3等5个差异表达显著基因的qPCR结果与转录组测序结果一致,差异表达显著基因主要富集在肌肉收缩、细胞黏附、间充质细胞增殖正调节等GO条目,心肌收缩、PI3K-Akt信号通路、Hippo信号通路等KEGG通路;40 kg组EGR2、RARRES2、TMOD4和SFRP2基因位于网络核心,EGR2、RARRES2、SFRP2在腹脂上调,TMOD4下调;80 kg组THBS1、PPARA、NRIP1和LPL基因位于网络核心,4个核心基因均在腹脂上调;120 kg组HTRA1、TSHR、LRRK2、STC2、SHOX2和SOD3基因位于网络核心,LRRK2、TSHR在腹脂上调,SHOX2、SOD3、STC2、HTRA1下调。结果提示,EGR2、THBS1、TSHR等14个基因作为核心基因精细调控大型迪庆藏猪不同生长阶段背脂与腹脂脂质代谢,10~40 kg,EGR2等4个基因位于核心,促进脂肪细胞分化、增殖的基因在腹脂上调,脂肪合成的开关基因下调;40~80 kg,THBS1等4个基因位于核心,促进甘油三酯合成、胆固醇形成、脂质积累的基因在腹脂上调;80~120 kg,LRRK2等6个基因位于核心,促进甘油三酯积累、脂肪酸氧化的基因在腹脂上调,抑制脂肪分解、脂滴形成的基因下调。本试验结果可为解析地方猪不同部位脂质差异性沉积的调控机制提供基础数据,为迪庆藏猪的靶向选育提供参考。

不同冻存时间对猪肌内脂肪含量及其与生产性状相关性的影响

[目的]本文旨在探究不同冷冻时间对猪肌内脂肪(intramuscular fat,IMF)含量的影响并分析IMF含量和其他生产性状的相关性。[方法]从299头杜洛克×(长白×大白)三元商品猪群中随机挑选52头作为试验对象,测定屠宰前活体重、屠宰后胴体重以及相关肉质性状;采集倒数第3~4肋骨间的背最长肌,采用索氏抽提法分别测定0 d鲜肉样、-80℃超低温冻存90和180 d肉样的IMF含量。对3个不同时间点测定的IMF含量进行相关性与差异显著性分析,并对3个不同时间点的IMF含量与测定的生产性状的相关性进行比较分析。[结果]0 d与冻存90 d的IMF含量呈极极显著相关(r=0.75),2个时间点测定的平均IMF含量不存在显著差异(P>0.05),但与0 d相比,冻存90 d的平均IMF含量呈上升趋势;0 d与冻存180 d的IMF含量呈显著相关(r=0.29),但与0 d相比,冻存180 d测定的平均IMF含量极显著升高(P<0.01)。性状相关分析结果显示,0 d和90 d的IMF含量与屠宰前活体重和胴体重呈极极显著相关(P<0.001),而180 d的IMF含量仅与胴体重呈极极显著相关(P<0.001),而且不同冻存时间对IMF含量与肉质性状的相关性产生不同程度的影响。[结论]肉样在-80℃冻存会增加IMF含量,但冻存90 d对IMF含量不会产生显著影响,而冻存180 d会极显著影响IMF含量。另外,低温冷冻对测定的IMF含量与生产性状的相关性产生不同程度的影响。本研究结果可为屠宰后肌肉块IMF含量测定的标准化以及行业标准的制定提供有价值的参考。

高脂高糖饮食对巴马小型猪肠道菌群的影响

目的探讨高脂高糖饮食8个月对巴马小型猪血脂和粪便中肠道菌群的影响。方法将10头巴马小型猪随机分为对照组(n=3)和实验组(n=7),对照组小型猪正常喂养,实验组给予高脂高糖饮食。各组动物分别于实验前及实验8个月后进行空腹采血,检测三酰甘油、总胆固醇、低密度脂蛋白胆固醇、高密度脂蛋白胆固醇等血脂指标。实验8个月后无菌采集各动物粪便,采用16S rRNA测序技术检测肠道菌群组成。结果高脂高糖饮食8个月后,实验组粪便中肠道菌群物种数量未见明显改变,厚壁菌门相对丰度增加,拟杆菌门和变形菌门丰度降低(P<0.05)。实验组小型猪体质量、三酰甘油、总胆固醇、低密度脂蛋白胆固醇水平均显著高于对照组(P<0.05)。结论高脂高糖饮食可以增加巴马小型猪粪便中厚壁菌门相对丰度,降低拟杆菌门和变形菌门相对丰度,提示这些肠道菌群的失调可能参与调节了宿主高脂血症的发生。

宁乡猪皮下脂肪与肌内脂肪组织转录组差异分析

为了比较分析宁乡猪皮下脂肪(subcutaneous fat,SAF)和肌内脂肪(intramuscular fat,IMF)组织脂肪沉积的分子机制,本文利用RNA-seq技术鉴定和分析宁乡猪SAF和IMF组织中差异基因表达谱。选取6头250日龄健康状况良好、种内个体体重相近(约85 kg)的雄性宁乡猪为实验材料,采集SAF与IMF组织样品。通过对两个脂肪组织转录组测序并进行GO(Gene Ontology)功能注释及KEGG(Kyoto Encyclopedia of Genes and Genomes)信号通路富集分析,得到与脂肪沉积和脂质代谢相关的差异基因。为验证测序数据结果的可靠性,本研究随机选取6个差异基因进行qRT-PCR验证。结果表明,宁乡猪SAF和IMF组织中有2406个基因差异表达,其中1422个基因表达上调,984个基因表达下调。通过GO功能注释分析发现,差异表达基因主要通过参与类固醇生物合成、不饱和脂肪酸的生物合成、甘油磷脂代谢及自噬途径等与脂质代谢相关途径,调控宁乡猪SAF和IMF的沉积。KEGG通路富集结果显示,差异基因主要富集在脂质结合、脂肪酸代谢过程、甘油酯代谢过程、脂类生物合成等与脂质代谢相关的生物学过程。qRT-PCR结果与测序结果一致,表明测序结果可靠。通过对宁乡猪SAF与IMF组织进行转录组测序以及生物信息学分析,筛选到TCAP、NR4A1、ACACA、LPL、ELOVL6、DGAT1、PRKAA1、ATG101、TP53INP2、FDFT1、ACOX1和SCD等基因与脂质代谢相关,这些基因可能在宁乡猪SAF与IMF组织中脂肪沉积和代谢过程发挥重要调控作用,对进一步研究宁乡猪脂肪沉积机制具有重要意义。