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.

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。

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。

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。

大型迪庆藏猪不同生长阶段背脂沉积差异基因及其调控通路分析

【目的】筛选大型迪庆藏猪不同生长阶段背脂沉积差异的关键基因并分析其调控途径。【方法】对体重长至40、80、120 kg的大型迪庆藏猪背脂组织进行转录组测序,测序数据进行拼接、比对、注释并进行功能富集分析、STEM趋势分析和互作网络分析。【结果】10~40 kg(S1阶段)与40~80 kg(S2阶段)、S2阶段与80~120 kg(S3阶段)比较分别筛选到845、558个显著差异表达基因(DEGs);差异表达基因STEM趋势分析显示,模块0、模块3和模块4的基因随大型迪庆藏猪体重增加而下调表达,模块14的基因先上调后轻微下调;显著差异基因互作网络显示,在模块0、模块3和模块4的基因互作网络中,PTGER3、CPT1B、LPIN3基因位于核心位置,PTGER3下调抑制脂肪分解、促进脂肪细胞增大,CPT1B下调降低脂肪酸氧化能力、导致甘油三酯增多,LPIN3下调维持脂质稳态;在模块14的基因互作网络中,AACS、SOCS3、AQP3、RPS6KA1位于核心位置,AACS上调促进脂肪细胞分化、脂肪细胞数量增多,SOCS3、RPS6KA1上调促进脂肪生成,AQP3上调促进脂肪细胞内甘油三酯增多,这与大型迪庆藏猪随体重增加背膘厚显著增加,但S1阶段与S2阶段背膘厚的增幅大于S2阶段与S3阶段的结果一致;对PTGER3、AACS等15个差异基因进行qPCR验证,定量结果与转录组结果一致。【结论】本研究筛选到15个调控大型迪庆藏猪背膘厚的潜在候选基因,可为迪庆藏猪的遗传改良提供参考。

基于转录组分析干扰FABP1基因对猪肌内脂肪沉积的影响

【目的】探究FABP1基因对猪肌内脂肪细胞生物学功能的影响机制,为进一步研究FABP1对猪肌内脂肪沉积和脂质代谢的调控作用提供参考依据。【方法】将sh-FABP1干扰载体和空载体sh-NC分别转染至香苏杂交猪肌内脂肪细胞中,36 h后收集转染后的肌内脂肪细胞,采用TRIzol^(®)Reagent总RNA提取试剂盒提取总RNA,待样本质检合格后,每个样品制备1µg的RNA总量用于测序。运用生物信息学进行基因表达水平分析(基因表达水平计算、样本间相关性评估)、基因差异表达分析[差异表达基因(DEGs)筛选和统计、DEGs火山图]和功能富集分析(GO富集分析、KEGG富集分析)。最后分别挑选4个上调基因和4个下调基因运用实时荧光定量PCR验证转录组测序数据。【结果】sh-FABP1与sh-NC之间总共筛选出1129个DEGs,与sh-NC组相比,sh-FABP1上调基因有624个,包括PRKAR2A、ACSL5、ELOVL5和MAPK1等;下调基因有505个,包括LPL、FABP3、IGFBP4和OLR1等。对sh-FABP1与sh-NC之间的DEGs进行功能富集分析,KEGG富集发现上调基因主要在细胞周期(Cell cycle)、肿瘤抑制蛋白(p53)和Notch信号通路中富集,下调基因主要富集在过氧化物酶体增殖物激活受体(PPAR)、磷脂酰肌醇3激酶-蛋白激酶B(PI3K-Akt)信号通路中。GO注释表明,有22个、15个和9个GO术语分别在生物过程(BP)、细胞成分(CC)和分子功能(MF)中显著富集(P<0.05,下同),显示与脂肪沉积相关具有显著差异的GO术语包括生物粘附(Biological adhesion)、生物调节(Biological regulation)、生物过程调节(Regulation of biological process)和代谢过程(Metabolic process)。【结论】FABP1基因可能通过调节LPL、FABP3、IGFBP4和OLR1等相关基因的表达、脂肪沉积和脂质代谢相关通路,从而调节脂质生成和代谢。

高脂诱导下雄激素缺乏小型猪肾脏脂质沉积的关键基因表达分析

目的:探讨高脂诱导条件下雄激素缺乏小型猪肾脏脂质沉积及关键基因表达的变化。方法:将雄性五指山小型猪随机分为3组,即不去势(IM)组、去势(CM)组和去势+睾酮(CMT)组,每组6只动物,均饲喂高脂饮食。12周后检测血清肾功能指标,测定肾脏甘油三酯(TG)和总胆固醇(TC)含量;进行肾脏苏木精-伊红(H&E)和油红O染色,观察其脂质沉积和组织病理学变化。利用转录组测序分析肾脏组织表达谱差异,并用RT-qPCR和Western blot方法验证参与TG合成、胆汁酸代谢和雌激素合成相关差异表达基因。结果:CM小型猪肾脏重量明显低于IM和CMT小型猪(P<0.05);与IM组和CMT组小型猪相比,CM小型猪血尿素氮含量显著升高(P<0.05),但血清肌酐和总蛋白水平没有显著变化;CM组小型猪肾脏内出现大量脂滴,且TG含量显著高于IM和CMT小型猪(P<0.05);与IM组和CMT组小型猪相比,CM组小型猪肾脏TG合成基因包括固醇调节元件结合转录因子1(SREBF1)、糖类应答元件结合蛋白(ChREBP/MLXIPL)和硬脂酰辅酶A去饱和酶(SCD)等表达升高,而胆汁酸代谢和雌激素合成基因包括法尼酯X受体(FXR/NR1H4)和雌激素受体1(ESR1)表达下调;睾酮处理能够逆转去势小型猪肾脏内脂质沉积及相关基因表达变化。结论:ESR1和NR1H4可能通过影响SREBF1脂质合成途径参与高脂诱导的雄激素缺乏小型猪肾脏脂质沉积过程。这为老年男性慢性肾脏疾病防治提供了新思路。

鉴别影响武夷黑猪肌内脂肪含量的肠道菌群

肌内脂肪含量是表征武夷黑猪肉品质的关键指标。肠道菌群在猪脂肪沉积过程中发挥着重要作用。然而,武夷黑猪肠道菌群研究尚未开展,肠道菌群与其肌内脂肪含量的关系仍旧未知。本研究利用16S rRNA基因测序解析了武夷黑猪肠道菌群的组成,揭示了肠道菌群中的优势细菌主要来自厚壁菌门、普氏菌属、罗氏菌属、瘤胃球菌属、螺旋菌属、密螺旋体菌属等,它们可能与武夷黑猪脂肪沉积能力强、耐粗饲、抗逆性好等生理特性有关。利用相关性分析,共鉴别了21个OTUs和8条功能途径与肌内脂肪含量显著相关(|r|>0.35,P<0.05),大多数与肌内脂肪含量相关的细菌可能通过调控多糖和氨基酸代谢来影响肌内脂肪沉积。本研究的发现为生产实践中通过干预肠道菌群、促进武夷黑猪肌内脂肪沉积奠定重要基础。

运用超声波技术评估猪活体肌内脂肪含量

[目的]研究在无损情况下猪肌内脂肪含量的估测方法,以提高预测模型的准确性。[方法]以229份硒都黑猪性能测定数据及超声波图像数据为研究对象,利用BioSoft Toolbox For Swine软件中感兴趣区域(region of interest,ROI)模块分割超声波图像,确定最佳感兴趣区域像素框大小(ROI Size)和个数,并通过逐步回归分析,以猪肌内脂肪含量为因变量,图像读取参数、体尺指标为自变量构建猪活体肌内脂肪含量估测模型。[结果]肌内脂肪含量与图像读取参数、宰前活重、胸围、腹围具有显著相关性,运用逐步回归分析得到脂肪含量估测模型,IMF=0.2495+0.1752×P+0.0070×W-0.0055×B+0.0159×A,模型拟合度R2为0.7252。[结论]运用超声波技术可以较准确地测定猪活体肌内脂肪含量,为实现种猪性能改良提供了技术支撑。

高效液相色谱-串联质谱法测定猪可食性组织中烯丙孕素残留

目的:测定猪可食性组织(肌肉、肝脏、脂肪)中烯丙孕素残留。方法:试样经β-葡萄糖醛酸酶/芳基硫酸酯酶酶解,乙腈提取,PRiME HLB固相萃取柱净化。以乙腈-0.1%甲酸水溶液作为流动相,经Waters UPLC BEH C_(18)反相色谱柱分离后于电喷雾正离子模式下检测,基质匹配外标法定量。结果:烯丙孕素在1~50μg/L的质量浓度范围内线性良好,线性相关系数R^(2)>0.99;该方法在猪肌肉、肝脏、脂肪组织中检测限为0.5μg/kg,定量限为1.0μg/kg。在3个添加水平下(1.0,2.0,10.0μg/kg),平均回收率为60.9%~89.8%,日内变异系数为0.8%~7.1%,日间变异系数为2.5%~11.6%。结论:该方法操作简便,适用于猪可食性组织中烯丙孕素残留的定性与定量分析。

藏猪和大约克猪FABP3基因多态性及差异表达分析

【目的】脂肪酸结合蛋白3(FABP3)参与长链脂肪酸的摄取及利用,在脂肪沉积中发挥重要作用。探究FABP3基因在藏猪和大约克猪间的基因多态性和表达差异可为藏猪品质改良提供分子机制参考。【方法】选取180日龄藏猪和大约克猪为研究对象,对两猪种FABP3基因5'侧翼区和CDS区进行单核苷酸多态性(SNPs)筛选,使用实时荧光定量检测FABP3基因在肝脏、背最长肌和背脂3个组织中的表达量。【结果】在FABP3基因5'侧翼区筛选到T-114C和C-635A等2个SNPs位点,且SNPs位点基因型频率在藏猪与大约克猪群体间均呈极显著差异(P<0.01);经转录因子预测发现这2个SNPs位点与前脂肪细胞的更新、分化以及脂肪沉积相关,推测这两个多态性位点是参与调控FABP3基因表达的重要功能位点。FABP3基因在藏猪肝脏、背最长肌中的表达量极显著高于大约克猪(P<0.01),在背脂中的表达量显著高于大约克猪(P<0.05)。【结论】推测FABP3基因可能为调控藏猪脂肪代谢的重要候选基因,在藏猪脂肪沉积中呈正向调控作用。