优质鸡肌内脂肪(IMF)和肌苷酸(IMP)含量比较分析

本文选取8个优质鸡新品系70日龄和92日龄鸡98只,将胸肌肌内脂肪(IMF)和肌苷酸(IMP)含量进行了比较。结果显示:不同品系、性别和日龄鸡肌内脂肪和肌苷酸含量均有较大差异。92日龄时D系肌内脂肪和肌苷酸显著高于其它各系(P<0.05)。70日龄和92日龄时肌内脂肪和肌苷酸含量在母鸡和公鸡间差异未达显著水平(P>0.05),但母鸡的肌苷酸含量均高于公鸡。肌内脂肪含量在70日龄时公鸡高于母鸡,而92日龄时母鸡高于公鸡。不同日龄间肌内脂肪和肌苷酸差异均不显著(P>0.05),但都有随日龄的增加而增加的趋势。     

青藏高原海东鸡屠宰性能与肌肉品质分析

本试验对青藏高原海东鸡的屠宰性能、肉质特性及营养成分进行了测定,结果表明,海东鸡活重、屠体率、全半净膛率、半净膛率、胸肌率在两性别之间差异不显著（P〉0．05）,但腿肌率公鸡显著高于母鸡（P〈0．05）;腹脂率母鸡极显著高于公鸡（P〈0．01）。失水率、胸肌嫩度、熟肉率、屠宰后45min内72-24h后的pH值在公、母鸡不同部位的肌肉间差异不显著（P〉0．05）。鸡肉中初水分、蛋白质含量在两性别间无显著差异（P〉0．05）,而脂肪含量公鸡明显低于母鸡,差异显著（P〈0．05）。     

不同品系优质鸡胸肌肌苷酸和鲜味氨基酸含量的比较

本文选取大恒3个优质鸡品系与2个杂交组合的7013龄和91日龄鸡各100只,对胸肌肌苷酸和鲜味氨基酸的含量进行了比较。结果显示：胸肌肌苷酸和鲜味氨基酸在不同品系间差异达到显著水平（P〈0．05）;不同日龄间,胸肌肌苷酸未达显著水平（P〉O．05）;鲜味氨基酸中除S05未达显著水平外（P〉0．05）,其余鲜味氨基酸均达到显著水平（P〈0．05）;不同性别间,胸肌肌苷酸S01、S05差异达到显著水平（P〈0．05）,其余胸肌肌苷酸含量也达到显著水平（P〈0．05）：鲜味氨基酸未达显著水平（P〉O．05）。     

建肽风味速肥散对育肥猪生长性能、胴彘性状及肉品质的影响

试验旨在研究饲料中添加中草药健肽风味速肥散对育肥猪的生产性能、胴体肉质及营养指标的影响。选用（60．25＋037）kg的“杜×长×大”三元杂交肉猪60头，采用单因子随机分组设计：对照组（基础日粮组）和试验组（基础日粮＋06％中草药健肽风味速肥散），每个处理组5个重复栏，每栏（3m×3m）6头，饲养周期为55d。研究结果显示，添加0．6％健肽风味速肥散试验组的三元猪平均日增重显著高于对照组，料重比显著低于对照组（P〈0．05）。健肽风味速肥散的添加对育肥猪的胴体参数和肉质也有显著的影响（P〈0．05）．与对照组相比，屠宰率无明显差异（P〉0．05），但试验组的瘦肉率和肌内脂肪含量分别提高了4．81％和4．5％（P〈0．05）．脂肪率、板油重和背膘厚分别降低了3．09百分点、0．28kg和0．45cm（P〈0．05）；添加0。6％健肽风味速肥散组的肉质嫩度、风味、多汁性和大理石纹也有明显改善（P〈0．05），失水率显著降低（P〈0．05），背肌蛋白含量和肌间脂肪含量也显著增加，总氨基酸含量和总氨基酸／蛋白质比例也显著提高（P〈0．05），有效地改善了育肥猪肉质。     

不同品种鸡肌肉营养价值及风味的研究

为研究玫瑰冠鸡肌肉营养价值和肉质风味,以良凤黄鸡和科宝肉鸡作为对照,分别测定其胸肌和腿肌中的氨基酸和肌苷酸(IMP)含量。结果表明:玫瑰冠公鸡胸肌、腿肌的氨基酸总量、必需氨基酸和鲜味氨基酸含量均显著高于科宝公鸡(P0.05),玫瑰冠母鸡胸肌的氨基酸总量极显著高于科宝母鸡(P0.01),鲜味氨基酸含量显著高于科宝母鸡(P0.05);玫瑰冠鸡和良凤黄鸡的E/T值、FAA/TAA值均高于科宝肉鸡;玫瑰冠公鸡的胸肌、腿肌IMP含量均极显著高于科宝公鸡(P0.01);玫瑰冠母鸡胸肌IMP含量极显著高于良凤黄母鸡、科宝母鸡(P0.01),玫瑰冠母鸡腿肌IMP含量显著高于科宝母鸡(P0.05);玫瑰冠鸡的矫正肌苷酸(IMPc)含量高于良凤黄鸡和科宝肉鸡。综上所述,玫瑰冠鸡与良凤黄鸡、科宝肉鸡相比,肌肉营养更丰富、风味物质含量更高,结果为玫瑰冠鸡肉品质研究和种质资源评估、开发利用奠定了坚实的理论基础。     

饲养方式对河田鸡脂肪代谢的影响

本文主要研究了饲养方式、性别、日龄对河田鸡脂肪代谢的影响。试验采用28日龄河田鸡,分为笼养组、室内平养组和草地散养组,每组4个重复,笼养组每重复公母各15只鸡,平养组每重复公母各30只鸡,草地散养组每重复公母各50只鸡,公母分开饲养,在第8、12、16周分别进行屠宰分析。结果表明,饲养方式、性别、日龄对脂肪合成关键酶FAS和ME的mRNA水平及其酶活性具有显著影响,散养鸡的肝脏FASmRNA和MEmRNA水平及其酶活性显著低于笼养鸡（P〈0．05）,与之相应的是散养鸡的肌内脂肪、肌间脂肪、皮下脂肪、腹脂率显著低于笼养鸡（P〈0．05）。随着日龄的增加,肝脏FAS、MEmRNA水平及其酶活性会随着增加。母鸡的肝脏FAS、MEmRNA水平及其酶活性显著高于公鸡（P〈0．05）。从酶活性与脂肪沉积的相关性可以看出,FAS活性与腿肌IMF含量、肌间脂肪宽、皮下脂肪、腹脂率呈正相关,并且与皮下脂肪和腹脂率呈显著正相关（P〈0．05）,FAS活性与胸肌IMF呈负相关,但相关性不显著。肝脏ME活性与腿肌IMF、胸肌IMF含量呈显著正相关（P〈0．05）,而与皮下脂肪、腹脂率呈负相关（P〉0．05）。     

饲养方式对维扬麻鸡父系肌肉品质影响研究

本文研究了不同饲养方式（网养、平养与放养）对维扬麻鸡父系肌肉品质的影响，结果显示：①不同饲养方式对胸肌脂肪含量无显著影响（P〉0．05）；脂肪酸含量最高的是油酸，然后分别是棕榈酸、亚油酸和硬脂酸。必需脂肪酸含量网养组最高，放养组最低。②放养组母鸡的胸肌硫胺素含量显著高于网养组，平养组母鸡介于网养组与放养组之间。③放养组母鸡胸肌肌苷酸含量显著高于平养组、网养组（P〈0．05）。④放养组母鸡胸肌肌纤维直径显著高于网养组（P〈0．05）；母鸡的腿肌纤维直径、腿肌纤维密度、胸肌纤维密度3个组织学指标在3种饲养方式间差异不显著（P〉0．05），但放养组的腿肌纤维密度、胸肌纤维密度都低于平养组、网养组，而放养组的腿肌纤维直径大于网养组与平养组。     

能量水平对大河乌猪肌纤维及肌肉营养成分的影响

为探讨不同日粮能量水平对大河乌猪肌肉肌纤维组织特性、营养成分的影响,采用单因子随机区组设计,选取体重相近(15.18±0.85)kg的大河乌猪54头,随机分为3组——HE(高能量组,消化能14.22 MJ/kg)、ME(中能量组,消化能12.98 MJ/kg)和LE(低能量组,消化能11.74 MJ/kg)开展饲养试验,各组在不同生长阶段日粮蛋白质、氨基酸、微量元素水平基本固定,猪体重达30、60、100 kg时分批屠宰,取背最长肌测定肌纤维直径和密度、常规营养成分、肌内脂肪、肌苷酸及肌肉脂肪酸含量。结果表明,日粮能量水平增加逐渐降低大河乌猪背最长肌的肌纤维直径,增加肌纤维密度,60 kg和100 kg体重时,HE组与LE组差异显著(P0.05)。30、60 kg和100 kg体重时,HE组大河乌猪肌肉中粗蛋白质含量显著低于LE组(P0.05),粗脂肪、肌内脂肪、肌苷酸含量均显著高于LE组(P0.05)。随能量水平增加,单不饱和脂肪酸(MUFA)显著降低,多不饱和脂肪酸(PUFA)则显著增加。30 kg和60 kg体重时,HE组MUFA含量显著低于ME组和LE组(P0.05),100 kg体重时HE组和LE组显著低于ME组(P0.05);30 kg和100 kg体重时,HE组PUFA含量显著高于ME组和LE组(P0.05),60 kg体重时,ME组显著高于LE组(P0.05)。不同能量水平对大河乌猪中、后期(60、100 kg体重时)肌肉饱和脂肪酸(SFA)和总不饱和脂肪酸(UFA)含量影响较大,HE、ME组和LE组间的SFA含量和UFA含量均差异显著(P0.05),其中SFA含量表现为LE组HE组ME组,UFA含量为ME组HE组LE组。综上,能量水平增加在一定程度上可降低大河乌猪肌肉粗蛋白质含量,提高粗脂肪、肌内脂肪和肌苷酸含量,改善肌肉脂肪酸的组成,增加肌肉风味物质。研究结果为通过营养调控手段改善大河乌猪的肉品质提供了一定的科学参考。     

优质鸡肌内脂肪(IMF)和肌苷酸(IMP)含量与屠宰及肉质性状的相关分析

选取92日龄不同优质新品系鸡50只,分析了肌内脂肪(IMF)和肌苷酸(IMP)含量与屠宰性状和肉质性状的相关性。结果显示:肌内脂肪(IMF)含量与腹脂率的相关系数最高(r=0.3234,P=0.0220),与腿肌率的相关系数达到了显著水平(P<0.05);肌苷酸(IMP)含量与胸肌率的相关系数最高(r=0.3604,P=0.0102)。总体上肌内脂肪(IMF)和肌苷酸(IMP)含量与肉质性状的表型相关较弱,其中肌内脂肪(IMF)含量与水分呈显著水平的表型负相关(P<0.05),肌苷酸(IMP)含量与水分呈显著水平的表型正相关(P<0.05),与pH值的相关系数也达到了显著水平(P<0.05)。     

不同品系鸡肌内脂肪和肌苷酸含量比较分析

为比较品系对鸡肉肌内脂肪和肌苷酸沉积的影响,选取9个品系鸡作为试验材料,采用索氏浸提法提取肌内脂肪,高效液相色谱仪分析肌苷酸含量。结果表明,同一性别不同品系间肌肉肌内脂肪含量存在显著差异(P＜0.05),除S07、D99和S06×S07 3个品系外,各品系肌内脂肪母鸡高于公鸡;肌苷酸含量在同一性别内不同品系间差异显著(P＜0.05),在S07、D99、S06×S01和S06×S07品系母鸡肌苷酸含量高于公鸡。本试验为鸡的进一步选育,特别对肌肉风味和鲜味特性的育种工作有重要的指导意义。     

南阳黑猪和大白猪脂肪酸分析及其综合评价

试验旨在研究南阳黑猪脂肪酸组成及含量,以期为中国地方猪种遗传资源的保护及开发利用提供理论依据。以南阳黑猪和大白猪为研究对象,每品种猪各12头,测量背最长肌脂肪酸含量及种类,以脂肪酸种类及数量、单不饱和脂肪酸（monounsaturated fatty acid,MUFA）、多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）、饱和脂肪酸（saturated fatty acid,SFA）、12-16碳饱和脂肪酸（饱和脂肪酸1,SFA1）、其他饱和脂肪酸（饱和脂肪酸2,SFA2）、不饱和脂肪酸（unsaturated fatty acids,UFA）、SFA2/SFA1、PUFA/MUFA、必需脂肪酸（essential fatty acid,EFA）、共轭亚油酸（conjugated linoleic acids,CLA）、PUFA/SFA、ω-6 PUFA/ω-3 PUFA等为指标,从营养、健康、风味及储存方面综合评价两个猪种猪肉脂肪酸品质。结果显示,两个猪种背最长肌中共检出30种脂肪酸,其中23种脂肪酸在两个猪种间有显著或极显著差异（P<0.05;P<0.01）;除SFA2/SFA1和ω-6 PUFA /ω-3 PUFA外,南阳黑猪其他指标均高于大白猪;SFA1、MUFA、PUFA、SFA、UFA、UFA/SFA、SFA2/SFA1、PUFA/MUFA、EFA、CLA、PUFA/SFA、ω-6 PUFA/ω-3 PUFA 11个指标在两个猪种间存在显著或极显著差异（P<0.05;P<0.01）,SFA2和PUFA/MUFA在两个猪种间无显著差异（P>0.05）。综合以上结果,南阳黑猪肌肉脂肪酸品质总体优于大白猪。     

Analysis and Comprehensive Evaluation of Fatty Acid in Nanyang Black Pig and Large White Pig

The experiment was carried out to study the composition and contents of fatty acids of Nanyang Black pig, and to provide a theoretical basis for the protection and exploitation of local pig genetic resources in China. 12 Nanyang Black pigs and 12 Large White pigs were chosen, and the composition and contents of fatty acids in longissimus dorsi muscle were measured, and the quality of fatty acids was comprehensive evaluated from nutrition, health, flavor and storage aspects. Monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), 12-16 carbon saturated fatty acids (SFA1), other saturated fatty acids (SFA2), unsaturated fatty acids (UFA), saturated fatty acids (SFA), SFA2/SFA1, MUFA/PUFA, essential fatty acid (EFA), conjugated linoleic acids (CLA), PUFA/SFA and ω-6 PUFA/ω-3 PUFA were used as the indexes of multiple comparison. The results showed that there were 30 kinds of fatty acids were detected and 23 of them had significant or extremely significant differences between the two pig breeds (P<0.05;P<0.01). Nanyang Black pig had higher values of above measured indexes than that of Large White pig in addition to SFA2/SFA1 and ω-6 PUFA/ω-3 PUFA. 11 indexes such as SFA1,MUFA,PUFA,SFA,UFA, UFA/SFA,SFA2/SFA1,PUFA/MUFA, EFA,CLA, PUFA/SFA and ω-6 PUFA/ω-3 PUFA differed significantly or extremely significantly between the two pig breeds (P<0.05;P<0.01), while SFA2 and PUFA/MUFA had no significant differences between the two pig breeds (P>0.05). In conclusion, the fatty acids of Nanyang Black pig were significantly better than that of Large White pig.     

Effects of dietary concentration and degree of polyunsaturation of dietary fat on endogenous synthesis and deposition of fatty acids in chickens

Two experiments were performed to assess the effect of different amounts of dietary polyunsaturated fatty acids (PUFA) on fatty acid composition of chickens. The contribution of de novo fatty acid synthesis to fatty acid profile was also estimated. In trial 1, different fat sources were blended in different ratios allowing a gradient of dietary PUFA (from 15 to 61 g/kg), keeping added fat constant (9%). In trial 2, PUFA-rich oil was added at increasing inclusion rates (2, 4, 6 and 8%), achieving a dietary PUFA content ranging between 27 and 59 g/kg. Increasing dietary PUFA inclusion resulted in an increase in PUFA deposition, with higher efficiency when dietary fat also provided saturated (SFA) and monounsaturated (MUFA) fatty acids (trial 1). Increasing dietary PUFA in both trials resulted in a decrease in SFA and MUFA concentration in the whole body. The estimated deposition of fatty acids from de novo synthesis was reduced when dietary fat content increased from 0 to 10%, varying between 35.34 and 17.66% for SFA and between 52.70 and 7.01% for MUFA in the whole body. The greater variation range for the MUFA supports the existence of a mechanism maintaining the SFA: (MUFA + PUFA) ratio within a specific range in biological membranes.     

Effect of dietary energy supply and fat source on the fatty acid pattern of adipose and lean tissues and lipogenesis in the pig

Forty Large White barrows were used to determine whether the effects of dietary fat source (tallow or soy oil at 5% of the diet) on lipogenesis and fatty acid profile of porcine adipose and lean tissue were dependent on dietary digestible energy density (8.8 vs 14.0 MJ DE/kg). Barrows were allocated to one of four groups and offered a fixed amount of feed (170 g x BW0.569/d) from 27 to 105 kg BW. The fatty acid composition of the backfat layers (BF), omental fat (OF), and i.m. adipose tissue of longissimus muscle as well as the activity of lipogenic enzymes of the adipose tissues were determined. Growth performance and carcass characteristics were affected by the dietary energy level (P < 0.01) but not by fat source. In accordance with the lower carcass fat deposition, the activity of lipogenic enzymes were decreased in the low-energy groups (P < 0.01). Within dietary energy level, inclusion of soy oil resulted in increased proportion of PUFA that was compensated by decreased saturated (SFA) and monounsaturated fatty acid (MUFA) proportions (P < 0.01). The SFA changes accounted for 23 (BF) and 24% (OF) of the PUFA changes in the high-energy and 31 (BF) and 39% (OF) in the low-energy diets. The differences in the fatty acid proportions between the soy oil and tallow group were more pronounced in the low-energy groups (fat source x energy density interactions: P < 0.01). Pigs fed the soy oil, low-energy diet had decreased SFA (BF: 28%; OF: 30%) and MUFA (BF: 13%; OF: 19%) concentration, whereas PUFA concentration was increased (BF: 59%; OF: 88%) compared with pigs fed the soy oil, high-energy diet. However, in the tallow groups, pigs fed the low-energy diets had slightly decreased SFA (BF: 14%; OF: 12%) and relatively constant MUFA (BF: 3%; OF: 1%), whereas PUFA concentration increased (BF: 39%; OF: 62%) relative to pigs fed the tallow high-energy diet. Lipid content of the i.m. adipose tissue was decreased in the low-energy groups (P < 0.05). Contrary to what was observed in the adipose tissues, increased PUFA concentration in the neutral and polar lipid fractions of the longissimus muscle was predominantly compensated by reduced MUFA deposition. In the polar lipid fraction, the proportions of both SFA and MUFA were decreased by the low-energy diet. Thus, the extent to which tissue concentration of fatty acids are altered from dietary fats differing in the degree of unsaturation depends on the dietary energy level.     

Effect of dietary mono- and polyunsaturated fatty acids on the fatty acid composition of pigs' adipose tissues.

In two experiments with growing-finishing pigs six different dietary fats were added to a conventional diet (control--C) to study the effects of dietary monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) on the fatty acid composition of backfat and kidney fat at similar amounts of double bonds in feed (Exp. 1:7% pork fat--PF, 4.95% olive oil--OO, 3.17% soybean oil--SO) or a constant amount of 5% of processed fats (Exp. 2: partially hydrogenated fat--SAT, fractionated pork fats: olein--OLE, stearin--STE). Compared with the control, PUFA were only slightly increased in backfat of pigs fed PF, OLE, STE or OO, although dietary PUFA intake was up to 70% higher. With SO PUFA were significantly increased in adipose tissues, predominantly at the expense of MUFA. Consequently, a non-linear relationship was found between PUFA intake and proportion in backfat. MUFA were incorporated at the expense of SFA, therefore, adipose tissues of OO fed animals were lowest in SFA. Despite comparable amounts of double bonds in feed (Exp. 1), the degree of unsaturation measured as fat score (sum of double bonds) was in the order SO > OO > PF > C. In contrast, the proportion of SFA was C > PF = SO > OO. Regarding the decisive role of SFA for fat consistency it may be concluded that MUFA should also be considered in feeding recommendations for pigs. Furthermore, in case of a high dietary supply of MUFA, a simple index of double bonds might not be sufficiently conclusive to judge pig fat quality.     

Genotype x environment interactions for fatty acid profiles in Bos indicus and Bos taurus finished on pasture or grain

A study was conducted to characterize lipid profiles in the M. longissimus thoracis of commercial Brazilian beef and to assess how those profiles are influenced by finishing system, genetic group, and their interaction. Intramuscular fat (IMF) and fatty acid (FA) profiles were determined in 160 bulls of the Bos taurus (n = 75) and Bos indicus (n = 85) genetic groups, finished on pasture (n = 46) or with grain supplementation (n = 114) and slaughtered in a commercial abattoir. Finishing system had a major impact on the deposition of IMF, as well as on the concentration of SFA, PUFA, and their ratio, but genetic groups showed important differences in the ability to convert SFA into cis-9 MUFA and to convert 16:0 into 18:0. When compared with pasture-finished animals, those finished with grain had greater content of IMF and SFA (P < 0.01), similar amounts of MUFA (P > 0.05), and about one-half the amount of PUFA (P < 0.01). Except for MUFA, differences in FA profiles among finishing systems were mostly mediated through their effect on IMF, even though the relationship of IMF with groups of FA differed among finishing systems. Under grain finishing, B. taurus had less SFA and greater MUFA than B. indicus (P < 0.01), but no differences were observed in PUFA (P > 0.05). With pasture-finishing, no differences were observed among the 2 genetic groups in SFA and MUFA (P > 0.05), but PUFA were decreased in B. taurus (P < 0.01). When genetic groups were compared in grain-finishing, B. taurus had a decreased ability for elongation and B. indicus had a decreased aptitude for desaturation of FA. On the other hand, with pasture-finishing a greater deposition of intermediate FA from ruminal biohydrogenation was observed in B. indicus than in B. taurus. Overall, FA profiles were affected more by finishing system in B. indicus than in B. taurus.     

日粮中添加整粒油籽对绵羊体脂脂肪酸组成的影响

日粮中分别添加相当于40 g粗脂肪的油菜籽(canola)、油葵籽、红花籽和亚麻籽,饲喂成年母羊35 d后屠宰,用气相色谱技术测定了背最长肌、尾部、背膘和肾脏4个部位脂肪的脂肪酸(FA)组成,结果表明:1)红花籽可显著降低肌肉中的短链、长链饱和脂肪酸及总饱和脂肪酸(SFA)的比例,而增加单不饱和脂肪酸(MUFA)和总不饱和脂肪酸(UFA)的比例,而添加油菜籽对肌肉的FA无显著影响;2)油葵显著降低了尾部短链和中链脂肪酸,提高了多不饱和脂肪酸(PUFA)与SFA的比值(P:S),油菜籽可显著降低尾部短链脂肪酸;3)添加亚麻籽有增加所有组织UFA和P:S值,降低SFA的趋势,但只有背膘脂肪中的PUFA显著增高;4)各类油籽对脂肪组织中的总SFA和MUFA无明显影响,其中肾脏脂肪受影响最小.     

枯草芽孢杆菌对7~28日龄羔羊生长和器官发育及肌肉脂肪酸的影响

旨在研究代乳粉中添加枯草芽孢杆菌（Bacillus subtilis）对7~28日龄羔羊生长性能、组织器官、腹泻率及肌肉组织脂肪酸含量的影响。本研究选取体况发育良好的7日龄湖羊公羔（双羔）30只,按同质性原则将羔羊随机分为2组,每组15只,每只为1个重复,给2组羔羊分别饲喂枯草芽孢杆菌含量为0和0.2%的代乳粉,试验期为21 d。在7、14、21和28日龄晨饲前进行称重,计算各生长阶段的平均日增重（average daily gain,ADG）。并且每天饲喂羔羊的同时观察羔羊腹泻情况,计算羔羊腹泻率。在28日龄时每组随机选择8只羔羊进行屠宰,屠宰后称量各组织器官重量,计算其相对指数,并采集羔羊背最长肌和肱二头肌,测量肌内脂肪含量。结果表明：1）枯草芽孢杆菌显著降低了7~14日龄羔羊的末重（P<0.05）,显著提高了15~21日龄和22~28日龄羔羊的平均日增重（P<0.05）,有提高7~28日龄羔羊平均日增重的趋势（P=0.100）;对7~28日龄羔羊腹泻率的无显著影响（P>0.05）。2）枯草芽孢杆菌显著降低了7~28日龄羔羊胰腺重量（P<0.05）,显著增加了蹄占宰前活重比例（P<0.05）,对其他组织器官没有显著影响（P>0.05）。3）枯草芽孢杆菌对7~28日龄羔羊皮张发育无显著影响（P>0.05）。4）枯草芽孢杆菌显著降低了羔羊背最长肌不饱和脂肪酸（unsaturated fatty acid,UFA）、单不饱和脂肪酸（monounsaturated fatty acid,MUFA）、棕榈酸、硬脂酸、二十烷酸、棕榈烯酸、油酸含量和MUFA∶多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）（P<0.05）,显著提高了十五烷酸、肉豆蔻烯酸、神经酸含量和饱和脂肪酸（saturated fatty acid,SFA）∶UFA （P<0.05）;显著降低了羔羊肱二头肌UFA、SFA、MUFA、棕榈酸、硬脂酸、二十烷酸、棕榈烯酸、油酸含量和MUFA∶PUFA （P<0.05）,显著提高了PUFA、n-6PUFA、肉豆蔻烯酸、神经酸含量和SFA∶UFA、PUFA∶SFA （P<0.05）。结果表明,在代乳粉中添加枯草芽孢杆菌对7~28日龄湖羊羔羊腹泻率、器官和皮张的发育无显著影响,但羔羊平均日增重和胴体重有升高趋势。枯草芽孢杆菌显著降低了湖羊羔羊背最长肌中UFA、MUFA、MUFA∶PUFA的含量和肱二头肌UFA、SFA、MUFA、MUFA∶PUFA的含量,显著提高了湖羊羔羊背最长肌中SFA：UFA的含量和肱二头肌中PUFA、n-6PUFA、SFA∶UFA、PUFA∶SFA的含量,表明枯草芽孢杆菌可通过对肌内脂肪酸组成比例和含量的影响,起到改善湖羊羔羊肉品质的作用。     

Fatty acid profiles and iodine value correlations between 4 carcass fat depots from pigs fed varied combinations of ractopamine and energy

A total of 54 finishing barrows (initial BW = 99.8 ± 5.1 kg; PIC C22 × 337) reared in individual pens were allotted to 1 of 6 dietary treatments in a 2 × 3 factorial arrangement of treatments with 2 levels of ractopamine (0 and 7.4 mg/kg) and 3 levels of dietary energy (high: 3,537, medium: 3,369, and low: 3,317 kcal/kg of ME) to determine the effects of feeding ractopamine and various dietary energy levels on the fatty acid profile of 4 carcass fat depots (jowl, belly, subcutaneous loin, and intramuscular) and the predictive relationships of calculated iodine value (IV) between these 4 fat depots. Carcasses were sampled for fat tissues at the anterior tip of the jowl, posterior to the sternum on the belly edge, three-quarters the distance around the LM (subcutaneous fat; SC), and within the LM (intramuscular fat; IMF). Feeding ractopamine diets reduced (P < 0.05) total SFA in SC and IMF and increased (P = 0.04) total MUFA in SC. Also, feeding ractopamine diets increased (P < 0.01) the IV of IMF. Total MUFA of belly fat was reduced (P < 0.05) when the low-energy diet was fed compared with the high-energy diet. Jowl fat total MUFA was reduced (P < 0.05) and total PUFA was increased (P < 0.05) when the medium-energy diet was fed compared with the high- and low-energy diets. Iodine values, independent of treatment, were 60.97, 64.51, 55.59, and 58.26 for belly, jowl, IMF, and SC fat depots, respectively. The IV correlations within fat depots were not consistent across dietary treatments because of the effect of treatments on carcass fatty acid characteristics. Feeding ractopamine diets shifted the fatty acid profile from SFA to MUFA in the SC depot. Feeding ractopamine diets did not change belly fat profiles, thus avoiding the potential negative effect of softening belly fat, which is detrimental to processing value. The IV of one fat depot may not be a good indication of IV of other fat depots because of weak correlation coefficients and the apparent influence of dietary treatment.     

Effects of breed, sex, and halothane genotype on fatty acid composition of pork longissimus muscle

The objective of this study was to estimate the effects of breed, sex, and halothane genotype on fatty acid composition and several fatty acid indices of lipid extracted from porcine LM. Purebred Yorkshire (n = 436), Duroc (n = 353), Hampshire (n = 218), Spotted (n = 187), Chester White (n = 173), Poland China (n = 124), Berkshire (n = 256), and Landrace (n = 187) pigs (n = 1,934; 1,128 barrows and 806 gilts) from 1991, 1992, 1994, and 2001 National Barrow Show Sire Progeny Tests were used. Pigs were classified as the HAL-1843 normal (NN) genotype (n = 1,718) or the HAL-1843 carrier (Nn) genotype (n = 216). For statistical analysis, a mixed model was used that included fixed effects of breed, sex, halothane genotype, test, slaughter date, interaction of breed x sex, and random effects of sire and dam within breed. Breed significantly affected the concentration of individual fatty acids, total lipid content, and the values of several fatty acid indices of LM. Duroc pigs had the greatest (P < 0.01) content of total SFA. Total MUFA concentration in Poland China pigs was greater (P < 0.05) than in all other breeds except the Spotted (P > 0.05). The concentrations of total PUFA were greater (P < 0.01) in Hampshire, Landrace, and Yorkshire pigs compared with those of other breeds. Significant sex differences for individual fatty acids were detected. Compared with gilts, barrows had greater (P < 0.01) concentrations of SFA and MUFA but lower (P < 0.01) total PUFA. Halothane genotype was a significant source of variation for the percentages of some fatty acids. Pigs with the carrier (Nn) genotype had lower concentrations of SFA (P < 0.05) and MUFA (P < 0.01) but a greater concentration of PUFA (P < 0.01) compared with NN pigs. There were significant negative correlations between total lipid content and individual PUFA and significant positive correlations between lipid concentration and most individual SFA and MUFA. In conclusion, the results suggest that breed and sex are important sources of variation for fatty acid composition of LM.