内蒙古牛马驼乳脂肪中脂肪酸构成的比较

从内蒙牧区采集蒙古牛混合乳14份(27头)、蒙古马混合乳15份(85匹)及双峰驼混合乳3份(7峰),共32份样品,对乳脂的脂肪酸构成进行检测和比较。结果表明,三种家畜乳脂肪酸构成差异显著。马乳脂中多不饱和脂肪酸(PUFA)为31.78%±7.03%,高于牛乳脂13倍,驼乳脂12倍,主要是马乳脂PUFA中亚油酸和α-亚麻酸高于牛乳和驼乳;马乳脂单不饱和脂肪酸(MUFA)为25.59%±7.77%,显著低于牛乳28.99%±3.72%和驼乳31.35%±2.84%;马、牛和驼乳脂饱和脂肪酸(SFA)质量分数分别为40.06%±5.19%,62.01%±4.98%和57.88%±3.88%;牛和驼乳脂中肉豆蔻酸、棕榈酸和硬脂酸均显著高于马乳。马、牛和驼乳SFA∶MUPA∶PUFA依次为1∶0.64∶0.79、1∶0.47∶0.04和1∶0.54∶0.05,PUFA/SFA为0.79、0.04和0.05,马乳最接近FAO/WHO推荐的比例(S∶M∶P=1∶1∶1)。     

母乳、牛乳及山羊乳脂肪酸组成的差异分析

采用气质联用法(GC-MS)测定东北区域不同泌乳期的母乳及牛乳和山羊乳常乳脂肪酸组成,并对其组成和含量进行差异分析,旨在为母乳脂质组学及以牛羊乳为基质的婴儿配方食品提供一定的理论基础。结果表明:母乳中主要脂肪酸为棕榈酸、油酸、亚油酸等,其中油酸含量最为丰富。饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)含量在不同泌乳期存在差异,其中SFA差异显著(p<0.05),初乳、过渡乳和成熟乳SFA含量分别为36.16%、37.89%、38.10%。牛乳和山羊乳主要以SFA为主,山羊乳SFA含量最高(69.07%),SFA中辛酸和癸酸是羊乳的特征脂肪酸,其含量显著高于母乳和牛乳(p<0.05)。山羊乳中中链脂肪酸(MCFA)含量最高(21.03%),是牛乳的1.5倍。其中,母乳SFA:MUFA:PUFA的比例为1.41:1.29:1,牛乳为19.12:9.98:1,山羊乳为11.14:3.98:1,山羊乳脂肪酸组成在比例上更加接近母乳。山羊乳在婴儿配方食品开发方面有更高的优势和开发空间。     

草鱼脆化过程中腹内脂肪酸组成变化

以不同脆化期的草鱼腹内脂肪为原料,采用气相-色谱质谱(GC-MS)联用技术,研究草鱼脆化过程中腹内脂肪酸组成变化。结果显示,不同脆化期的草鱼腹内脂肪中共检出19种脂肪酸,其中饱和脂肪酸(saturated fatty acid,SFA)7种,单不饱和脂肪酸(monounsaturated fatty acid,MUFA)2种,多不饱和脂肪酸(polyunsaturated fatty acid,PUFA)10种。随着脆化时间的延长,MUFA含量显著增加,PUFA、n-6 PUFA含量显著减少(p0.05)。整个脆化过程中,SFA∶MUFA∶PUFA的比值近似于1∶2∶1,以普通草鱼最为接近。而n-3 PUFA在脆化20 d时开始减少(p0.05),始终低于普通草鱼。n-6/n-3 PUFA的比值为3.36%±0.04%~4.10%±0.04%,脆化20 d时最高。研究表明,虽然脆化改变了腹内脂肪酸的组成,但脆肉鲩腹内脂肪仍具有较好的开发价值。     

不同乳源新鲜干酪中脂肪酸组成和含量的对比

采用气相色谱-质谱联用(GC-MS)的测定方法,分别对由牦牛乳和荷斯坦牛乳制得的新鲜干酪中脂肪酸的组成和含量进行测定。结果表明:新鲜牦牛乳硬质干酪中检出的脂肪酸种类和总相对含量均少于新鲜荷斯坦牛乳硬质干酪,荷斯坦牛乳硬质干酪中总脂肪酸相对含量是牦牛乳硬质干酪中的1.00倍。两种干酪中,最主要的脂肪酸均为棕榈酸(C16∶0)、9-十八碳烯酸(C18∶1)和硬脂酸(C18∶0),这三种脂肪酸的总和占两种干酪的71%以上。牦牛乳干酪中饱和脂肪酸(SFA)种类比荷斯坦乳干酪多1种,但是相对含量低了1.68%;不饱和脂肪酸(UFA)种类比荷斯坦牛乳干酪少2种,但是相对含量是其1.05倍;单不饱和脂肪酸(MUFA)的种类和相对含量均低于荷斯坦牛乳干酪;多不饱和脂肪酸(PUFA)的种类比荷斯坦牛乳干酪少1种,但相对含量是其2.85倍;短链(SCFA)和长链脂肪酸(LCFA)相对含量分别是荷斯坦牛乳干酪的1.10和1.23倍。综上所述,放牧季节和牧草营养成分影响了乳脂肪酸的组成和含量,从而进一步影响了干酪中的脂肪酸组成和含量。     

油瓜种仁油与8种食用油理化及挥发性成分对比分析

以云南西双版纳油瓜种仁油为原料,对比分析核桃油、花生油、黑芝麻油、玉米胚芽油、大豆色拉油、大豆油、橄榄油、葵花籽油共9种油脂的理化成分、矿物质含量及脂肪酸组成。结果表明,油瓜种仁油过氧化值为(5.90±0.81)mmo L/kg,水分及挥发物为(0.31±0.07)%,杂质含量为0.25%,酸值为(11.21±0.13)mg KOH/g。矿物质含量(除锰含量)位列所检油脂第二0.262 mg/kg,铜含量位列第七0.284 mg/kg,磷、锌、铁、镁、钙、铜、钠、钾含量均最高。油瓜种仁油共检出9种脂肪酸,以亚油酸45.89%、棕榈酸29.85%、油酸14.14%为主。MUFA(单不饱和脂肪酸)∶PUFA(多不饱和脂肪酸)∶SFA(饱和脂肪酸)=1∶3.3∶2.7。n-3 PUFAs∶n-6 PUFAs=1∶63。建议与橄榄油复配,复配后MUFA∶PUFA∶SFA=1∶1∶0.8。或油瓜种仁油、橄榄油、核桃油三者复配,复配后MUFA∶PUFA∶SFA=1∶1∶0.7。调和n-3与n-6 PUFAs比例,直接添加亚麻酸等n-3 PUFAs类油脂纯品改善脂肪酸比例。     

河川沙塘鳢肌肉营养成分的分析和评价

为了解河川沙塘鳢肌肉的营养价值,采用生化分析手段对生态养殖的2 龄冬季河川沙塘鳢进行肌肉营养成分分析和品质评价。结果显示,冬季河川沙塘鳢的肌肉水分、粗蛋白、粗脂肪和粗灰分含量分别为78.08%、18.26%、1.11%和1.30%。18 种被检出的常见氨基酸中含量最高的3 种氨基酸是谷氨酸、天冬氨酸和赖氨酸;肌肉鲜样中氨基酸总量（total amino acid,TAA）、必需氨基酸（essential amino acids,EAA）、半必需氨基酸（half essential amino acids,HEAA）和鲜味氨基酸（delicious amino acid,DAA）分别为19.47%、7.74%、1.80%和7.09%;EAA/TAA、EAA/非必需氨基酸（nonessential amino acids,NEAA）、DAA/TAA分别为39.75%、77.92%和36.42%;第1、第2限制性氨基酸分别是色氨酸和缬氨酸;必需氨基酸指数和支链氨基酸与芳香族氨基酸的比值（F值）分别为74.86和2.15。肌肉干样中检出6 种饱和脂肪酸（total saturated fatty acids,SFA）、4 种单不饱和脂肪酸（monounsaturated fatty acids,MUFA）和10 种多不饱和脂肪酸（polyunsaturated fatty acids,PUFA）;ΣSFA、ΣMUFA、ΣPUFA、Σn-3 PUFA、二十碳五烯酸＋二十二碳六烯酸和Σn-6 PUFA分别为31.83%、20.91%、47.27%、30.60%、23.58%和15.56%,ΣSFA/ΣUFA和Σn-3 PUFA/Σn-6 PUFA分别为0.47%和1.97%。结果表明,河川沙塘鳢是一种营养价值较高、味道鲜美的优质鱼类,且有一定的保健作用;冬季河川沙塘鳢肌肉营养价值高于繁殖季节的,其粗蛋白和粗脂肪含量较高且氨基酸和脂肪酸组成较优。     

微波和超声波辅助处理对干制横山羊肉中脂肪酸的影响

陕西横山羊肉属于国家地理标志产品,为研究微波和超声波辅助处理对干制羊肉中脂肪酸种类和含量的影响,分别采用微波、超声波处理干制横山羊肉,用气相色谱-质谱法(gas chromatograph-mass spectrometer,GC-MS)测定2种处理方式下干制羊肉中脂肪酸的种类及含量。结果表明:与空白处理组相比,采用微波和超声波辅助处理对干制羊肉中脂肪酸的种类无影响,但对脂肪酸相对含量有一定影响,其中微波辅助处理在降低总饱和脂肪酸(saturated fatty acids,SFA)的同时增加了总多不饱和脂肪酸(polyunsaturated fatty acids,PUFA)的相对含量(P0.05),n-6/n-3 PUFA值减小(P0.05),使其符合营养学推荐水平。超声波辅助处理对干制羊肉中总SFA、单不饱和脂肪酸(monounsaturated fatty acids,MUFA)和PUFA相对含量影响不显著(P0.05),但明显降低了C_(14∶0)及cis-9 C16∶1的相对含量(P0.05)。结论:微波和超声波辅助处理均可不同程度地提高了干制横山羊肉脂肪酸营养价值,以微波辅助处理效果较明显。     

厦门白姑鱼腌制加工过程中的脂肪酸变化分析

探讨厦门白姑鱼（Argyrosomus amoyensis）腌制加工过程中的脂肪酸的变化,并结合脂肪氧化相关指标：过氧化值（peroxide value,POV）及硫代巴比妥酸反应物（thiobarbituric acid reactive substance,TBARS）值,确定脂肪氧化对脂肪酸组成的影响。从腌制加工的7 个关键工序中取样,采用气相色谱-质谱联用法分析脂肪酸,同时考察POV及TBARS值。结果表明：厦门白姑鱼原料含26.41%的饱和脂肪酸（saturated fatty acids,SFA）、20.26%的单不饱和脂肪酸（monounsaturated fatty acids,MUFA）和53.33%的多不饱和脂肪酸（polyunsaturated fatty acids,PUFA）,共24 种,必需脂肪酸占12.49%,二十碳五烯酸（eicosapentaenoic acid,EPA）和二十二碳六烯酸（docosahexaenoicacid,DHA）占40.70%。在腌制加工中,SFA含量显著增加,MUFA含量和PUFA含量显著降低（P＜0.05）。POV和TBARS值都呈现了先增后减的趋势,分别在烘干1 d和3 d出现峰值。相关性分析表明,SFA与MUFA呈显著负相关（P＜0.05）,与PUFA呈极显著负相关（P＜0.01）,MUFA和PUFA没有相关性;SFA与POV和TBARS值呈现显著正相关（P＜0.05）,而PUFA与POV和TBARS值分别呈显著（P＜0.05）和极显著负相关（P＜0.01）。因此,厦门白姑鱼脂肪酸种类多,含有丰富的不饱和脂肪酸,腌制加工过程对主要8 种脂肪酸有显著影响,脂肪的氧化使SFA含量增加,同时使PUFA含量降低,PUFA更容易发生氧化。     

油瓜种仁油与八种食用油理化及挥发性成分对比分析

以云南西双版纳油瓜种仁油为原料,对比分析核桃油、花生油、黑芝麻油、玉米胚芽油、大豆色拉油、大豆油、橄榄油、葵花籽油共九种油脂的理化成分、矿物质含量及脂肪酸组成。结果表明,油瓜种仁油过氧化值为5.90±0.81 mmoL/kg,水分及挥发物为0.31±0.07 %,杂质含量为0.25 %,酸值为11.21±0.13 mgKOH/g。矿物质含量除锰含量位列所检油脂第二0.262 mg/kg,铜含量位列第七0.284 mg/kg,磷、锌、铁、镁、钙、铜、钠、钾含量均最高。油瓜种仁油共检出9种脂肪酸,以亚油酸45.89%、棕榈酸29.85%、油酸14.14%为主。MUFA（单不饱和脂肪酸）∶PUFA（多不饱和脂肪酸）∶SFA（饱和脂肪酸）=1∶3.3∶2.7。n-3 PUFAs∶n-6 PUFAs=1∶63。建议与橄榄油复配,复配后MUFA﹕PUFA﹕SFA=1﹕1﹕0.8。或油瓜种仁油、橄榄油、核桃油三者复配,复配后MUFA﹕PUFA﹕SFA=1﹕1﹕0.7。调和n-3 与n-6 PUFAs比例,直接添加亚麻酸等n-3 PUFAs类油脂纯品改善脂肪酸比例。     

GC-MS测定人乳及动物乳中支链脂肪酸组成

支链脂肪酸（BCFA）是乳中微量但对婴幼儿的生长发育具有重要意义的生物活性成分。利用GC-MS对人乳和4种动物乳（牛乳、羊乳、牦牛乳、骆驼乳）中BCFA种类及含量进行测定。结果表明：5种乳中共有64种脂肪酸,其中含15种BCFA,17种饱和脂肪酸（SFA）,18种单不饱和脂肪酸（MUFA）和14种多不饱和脂肪酸（PUFA）;BCFA含量呈现出很大的物种间差异,动物乳中的支链脂肪酸含量显著高于人乳（p<0.001）,牛乳、牦牛乳、羊乳、骆驼乳和人乳中BCFA多为异构（iso）和反异构（anteiso）BCFA,含量分别为2.82%、4.90%、3.35%、8.00%和0.28%;人乳中BCFA受孕龄影响显著（p<0.01）,足月儿乳母的母乳中含有丰富的BCFA。     

Fatty acid profiles of milk from Holstein cows,Jersey cows,buffalos, yaks,humans, goats,camels, and donkeys based on gas chromatography–mass spectrometry

Due to the diversity and limitation of determination methods, published data on the fatty acid (FA) compositions of different milk samples have contributed to inaccurate comparisons. In this study, we developed a high-throughput gas chromatography–mass spectrometry method to determinate milk FA, and the proposed method had satisfactory linearity, sensitivity, accuracy, and precision. We also analyzed the FA compositions of 237 milk samples from Holstein cows, Jersey cows, buffalos, yaks, humans, goats, donkeys, and camels. Holstein, Jersey, goat, and buffalo milks contained high content of even-chain saturated FA, whereas goat milk had higher content of medium- and short-chain FA (MSCFA). Yak and camel milk are potential functional foods due to their high levels of odd- and branched-chain FA and low ratios of n-6 to n-3 polyunsaturated FA (PUFA). Human milk contained lower levels of saturated FA, MSCFA, and conjugated linoleic acid, and higher levels of monounsaturated FA and PUFA. As a special nonruminant milk, donkey milk contained low levels of monounsaturated FA and high levels of PUFA and MSCFA. Based on the FA profiles of 8 types of milk, nonruminant milk was distinct from ruminant milk, whereas camel and yak milk were different from other ruminant milks and considered as potential functional foods for balanced human diet.     

Fatty acid profile characterization in colostrum,transition milk,and mature milk of primi- and multiparous cows during the first week of lactation

The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 16% and 27% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 42% higher in PP cows throughout the milking period, as well as 15% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 13% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 23% higher in colostrum than mature milk and 25% higher in MP cows. Linoleic acid was also 13% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 63% higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 25% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.     

Fatty acid profile characterization in colostrum,transition milk,and mature milk of primi- and multiparous cows during the first week of lactation

The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 38% and 19% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 72% higher in PP cows throughout the milking period, as well as 13% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 25% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 29% higher in colostrum than mature milk and 33% higher in MP cows. Linoleic acid was also 15% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 2.7-fold higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 40% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.     

Milk composition and flavor under different feeding systems: A survey of dairy farms

Understanding the influence of regional dietary factors on the flavors of milk and dairy products will provide consumers with more options and promote the conservation of regional resources and the original terroir. The objective of this study was to evaluate the influence of regional differences in feeding systems on the composition, fatty acid content, and flavor of pasteurized milk at the farm level. Nine dairy farms using grass silage (GS), 6 farms using maize silage (MS), and 4 farms using by-products (BP) as the characteristic feed components were chosen for this survey. Fresh milk was sampled once per month from September 2008 to February 2009 at each dairy farm. The percentages of GS, MS, and BP (soybean curd residue or brewer's grain) in the feed were 32.4, 22.1, and 15.1%, respectively. The milk fat, protein, and lactose contents did not differ among the milks from farms with different feeding systems. Fatty acids with chain lengths of less than C16 and saturated fatty acids were present at higher concentrations in the milks from the GS and MS farms than in the milk from the BP farms; conversely, fatty acids with chain lengths greater than C18 and unsaturated fatty acids (UFA), including mono- (MUFA) and polyunsaturated fatty acids (PUFA), were present at higher concentrations in the milks from the BP farms than in the milks from the GS farms. No significant differences were detected in milk flavor, evaluated as sweetness, body, texture, aftertaste, and palatability, between the milks from the farms with different feeding systems. The proportion of BP in the cow's diet was positively correlated with the concentrations of fatty acids with chain lengths greater than C18 and with UFA, MUFA, and PUFA. In contrast, the proportion of GS in the diet was positively associated with the levels of milk fat, protein, fatty acids with chain lengths less than C16, and SFA. The MUFA, PUFA, UFA, and fatty acids with chain lengths greater than C18 were not associated with any of the milk flavors. These results suggest the regional differences in feeding systems contribute to the differences in the fatty acid compositions of milk at the farm level. However, these differences do not influence the flavor of pasteurized milk. Thus, more specific feed profiles will be required to provide a specific regional flavor to pasteurized milk.     

Prediction of milk fatty acid composition by near infrared reflectance spectroscopy

Near-infrared reflectance spectroscopy (NIRS) (700–2500 nm) was used to predict milk fatty acid (FA) composition. Broad FA variability was ensured by using experimental cow milk derived from different feeding regimes (pasture and preserved forages with or without lipid supplements). Detailed FA composition was analyzed by gas chromatography. Predictive equations (354 samples) were developed for liquid and oven-dried milk samples using modified partial least squares with cross-validation and external validation (114 samples). Coefficient of determination in external validation (R²V) and residual predictive deviation (RPD) were good (R²V ≥ 0.88; RPD ≥ 3.26) for saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), unsaturated fatty acids (UNSAT), trans FA, trans and cis-C18:1, caproic, caprilic, capric, lauric, myristic, palmitic and oleic acids in oven-dried milk, approximate for polyunsaturated fatty acid (PUFA), stearic, vaccenic and rumenic acids (R²V ≤ 0.81; RPD ≤ 3.23) and poor for linoleic, linolenic, total n-6 and n-3 acids. The quantification was more accurate for oven-dried milk, but good results were also obtained for SFA, MUFA, palmitic and oleic acids in liquid milk.     

Short communication: Genetic parameters of individual fatty acids in milk of Canadian Holsteins

The objective of the present study was to estimate heritabilities of milk fatty acids (FA) and genetic and phenotypic correlations among milk FA and milk production traits in Canadian Holsteins. One morning milk sample was collected from each of 3,185 dairy cows between February and June 2010 from 52 commercial herds enrolled in Valacta (Ste-Anne-de-Bellevue, Quebec, Canada). Individual FA percentages (g/100 g of total FA) were determined for each sample by gas chromatography. After editing the data, 2,573 cows from 46 herds remained. Genetic parameters were estimated using multitrait animal models fitted under REML. The model included fixed effects of age at calving and stage of lactation each nested within parity and random effects of herd-year-season of calving, animal, and residual. The pedigree of animals with data was traced back 5 generations on both the male and female sides to account for relationships among animals. The estimates of heritability for individual FA ranged from 0.01 to 0.39, with standard errors ranging from 0.01 to 0.06. Generally, monounsaturated FA (MUFA) and saturated FA (SFA) showed higher heritability estimates than polyunsaturated FA (PUFA). Overall, SFA were negatively genetically correlated with MUFA and PUFA, whereas genetic correlations between MUFA and PUFA were positive. The SFA showed positive associations with fat yield and fat percentage, whereas unsaturated FA were negatively associated with fat yield and fat percentage. Bovine milk FA composition could be improved through genetic selection, and selection for MUFA or against SFA could alter the bovine milk fat profile in a desirable direction.     

SFC-Q-TOF-MS法鉴定4 种家畜乳甘油三酯及特征分析

对家畜乳尤其是特种家畜乳脂肪甘油三酯（triacylglycerols，TAGs）进行系统鉴定和研究。采集荷斯坦牛、山羊、蒙古马和双峰驼原奶样品31 份，用超临界流体色谱-四极杆飞行时间质谱（supercritical fluid chromatography-quadruple time-of-flight mass spectrometry，SFC-Q-TOF-MS）检测鉴定TAGs组成，并进行主成分分析（principal component analysis，PCA）。结果表明：4?种家畜乳共鉴定出145?种TAGs，相对分子质量为470～888，酰基链总碳数为24～54，双键数为0～9；由14?种碳数4～20、双键数0～3的脂肪酸构成。牛、山羊、马和骆驼乳分别鉴定出60、66、74?种和44?种TAGs。马、骆驼、牛和山羊乳不饱和TAGs相对含量依次为82.2%、61.1%、51.7%和43.8%；马乳含亚麻酸的TAGs高达45.43%；骆驼乳TAGs脂肪酸组成最简单，至少含肉豆蔻酸、棕榈酸、硬脂酸和油酸中的一种；驼乳脂肪O-P-O相对含量最高，为5.04%，山羊乳脂肪最低，仅为1.8%；山羊乳主要TAGs都由饱和脂肪酸组成。4?种家畜乳的基峰色谱图差异明显，对TAGs进行PCA?4?种家畜乳样品以物种聚类明显分离，距离远近符合物种分类学，提示TAGs可建模判别家畜乳的物种。     

Effect of feeding on fatty acid composition of muscles and adipose tissues in young goats raised in the Argan tree forest of Morocco

The characteristics of meat from goats raised in the Argan tree forest in the south-western part of Morocco were studied in two experiments. Each experiment was carried out on three groups of six male goats. They were reared either indoors (IC) and fed concentrate or outdoors where they grazed in the Argan tree forest and were offered concentrate (OC) or only Argan fruit pulp (OS). Outdoor-raised goats had a very low growth rate in the first experiment (34 g/d), whereas it was relatively high in the second experiment (64 g/d) in which herbaceous vegetation availability was higher. In each experiment, omental (OM) and perirenal (PR) weights were the lowest in the two groups of goats raised outdoors. Lipid and cholesterol contents in muscles were lower in goats raised in the Argan tree forest than in those raised indoors. Outdoor-raised goats had particularly high proportions of odd-chain fatty acids (FA), branched-chain (FA) of the iso and anteiso series in adipose tissues and muscles and higher n-6 and n-3 polyunsaturated FA (PUFA) proportions and a lower n-6:n-3 PUFA ratio than indoor-raised goats. Indoor-raised goats had a higher proportion of palmitic acid and a lower proportion of archidic acid than outdoor-raised goats. In indoor-raised goats, the proportions of Δ9 straight-chain mono-unsaturated fatty acids (MUFA) (C(16:1n-7) and cis C(18:1n-9)) were relatively higher than those of total MUFA, because of lower percentages of some MUFA, such as C(16:1n-9) and other isomers of oleic acid. The low fat content and FA profile of the meat from the goats reared in the Argan tree forest conveyed beneficial characteristics to this meat in regards to human health. The relatively high contents of branched-chain FA of iso and anteiso series and PUFA in the meat from goats raised in the Argan tree forest could be considered as a sign of typicity.     

Correlation of animal diet and fatty acid content in young goat meat by gas chromatography and chemometrics

The meat fatty acids (FA) profiles of caprines submitted to different dietary treatments were determined by gas chromatography. The data were treated by Chemometrics to consider all variables together. The contents of saturated FA (SFA), monounsaturated FA (MUFA), polyunsaturated FA (PUFA), omega-3 (n-3) FA, and omega-6 (n-6) FA in 32 samples were analyzed. PUFA:SFA and n-6:n-3 ratios were also considered. The multivariate methods of hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used to analyze the experimental results. HCA can group samples according to their basic composition, and PCA can explain the relationship among the dietary treatments according to the meat fatty acid composition. Treatment 1 presented the highest n-6 FA concentration, PUFA:SFA, and n-6:n-3 ratios, and the lowest MUFA and n-3 concentrations. Opposite results were observed for treatment 4. Treatments 2 and 3 were highly similar with differences mainly in SFA and MUFA concentrations.