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。     

驼、牛、羊乳中脂肪酸含量的比较分析

采用气相色谱法对驼、牛、羊乳3 种乳中脂肪酸（fatty acids,FA）种类及含量进行比较。结果表明,3 种乳脂肪酸种类和含量差异显著。驼乳检测出33 种脂肪酸,棕榈酸相对含量最高（（23.73±2.17）%）;驼乳的多不饱和脂肪酸（polyunsaturated fatty acids,PUFA）相对含量（（4.09±0.54）%）显著高于牛乳和羊乳;牛乳中检测出29 种脂肪酸,棕榈酸相对含量最高（（27.44±2.45）%）;羊乳检测出34 种脂肪酸,且油酸相对含量最高（（30.89±3.57）%）。3 种乳中羊乳单不饱和脂肪酸（monounsaturated fatty acids,MUFA）含量最高（（35.26±3.86）%）。此外,结合主成分分析和相关性分析方法,对驼乳的脂肪酸含量进行进一步分析,结果显示,驼乳的饱和脂肪酸（saturated fatty acids,SFA）∶MUFA∶PUFA为1∶0.60∶0.08,驼乳更接近联合国粮食及农业组织/世界卫生组织推荐SFA∶MUFA∶PUFA为1∶1∶1。PUFA与短链脂肪酸（short-chain fatty acids,SCFA）、长链脂肪酸（long-chain fatty acids,LCFA）呈负相关,与n-6 FA相关性最大（0.978）;SCFA与LCFA呈正相关,n-6 FA与n-3 FA呈正相关。     

6种常见食用蜻蜓稚虫含油率与脂肪酸组成分析

为评价6种云南和贵州地区常见食用蜻蜓稚虫油脂的营养价值,采用索氏提取法和GC-MS分析和比较了闪蓝丽大蜻、碧伟蜓、小团扇春蜓、黄蜻、大团扇春蜓、赤褐灰蜻6种蜻蜓稚虫的含油率和油脂脂肪酸组成。结果表明:6种蜻蜓稚虫含油率为5.72%~11.90%,其中大团扇春蜓的含油率最高,赤褐灰蜻的最低。6种蜻蜓稚虫油脂分别鉴定出18~29种脂肪酸,其中包括奇数碳脂肪酸、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)等具有特殊功能的脂肪酸;不饱和脂肪酸(UFA)占脂肪酸总量的61.50%~65.22%,多不饱和脂肪酸(PUFA)占UFA总量的29.57%~50.00%,棕榈酸相对含量最高,为17.57%~24.61%;n-6 PUFA与n-3 PUFA比值为0.68~1.30,接近淡水鱼类,黄蜻和赤褐灰蜻的饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)和PUFA的含量之比分别为1.17∶1.2∶1和1.3∶1.18∶1,接近北大西洋公约组织和美国心脏协会推荐的人体摄入比(1∶1.5∶1和(0.8~1)∶1.5∶1)。     

不同类型膳食脂肪酸对肥胖小鼠肝脏及其血液中脂肪酸组成和代谢相关基因影响

目的探讨不同类型膳食脂肪酸对肥胖小鼠肝脏及其血液中脂肪酸组成及代谢相关基因的影响。方法 8周龄雄性C57BL/6小鼠随机分为7组,即对照组(喂基础饲料)、长链饱和脂肪酸(LCSFA)组(喂猪油高脂饲料)、中链饱和脂肪酸(MCSFA)组(喂椰子油高脂饲料)、n-3多不饱和脂肪酸(n-3 PUFA)组(喂亚麻籽油高脂饲料)、n-6多不饱和脂肪酸(n-6 PUFA)组(喂大豆油高脂饲料)、单不饱和脂肪酸(MUFA)组(喂橄榄油高脂饲料)和反式脂肪酸(TFA)组(喂8%氢化大豆油高脂饲料),每组10只,共干预16周,所有种类饲料总能量均相同,基础饲料脂肪供能比为10%,各高脂饲料脂肪供能比均为45%,喂养周期结束后,禁食12 h,麻醉后立刻解剖取出肝脏。采用气相色谱法分析肝脏及其血液中脂肪酸组成的变化,实时荧光定量聚合酶链式反应(PCR)检测肝脏脂肪酸代谢相关基因的表达,肝脏脂质沉积采用油红O染色法检测。结果与对照组比较,LCSFA组、MCSFA组、n-6 PUFA组、MUFA组和TFA组小鼠肝脏中均出现明显的脂质沉积,n-3 PUFA组小鼠肝脏未出现明显的脂质沉积。与对照组比较,LCSFA组小鼠肝脏及血液中总n-6 PUFA和总PUFA含量升高; n-3 PUFA组小鼠肝脏及血液中总n-3 PUFA和总PUFA含量增加,但总MUFA含量减少; n-6 PUFA组小鼠肝脏及血液中总n-6PUFA、总n-3 PUFA和总PUFA含量升高,但总饱和脂肪酸(SFA)和总MUFA含量降低; MUFA组小鼠肝脏及血液中总SFA含量减少; TFA组小鼠肝脏及血液中C18∶1 n-9t(TFA)含量升高;以上差异均有统计学意义(P0. 05)。LCSFA组和MCSFA组小鼠肝脏脂肪酸代谢基因固醇调节元件结合蛋白1(SREBP-1c) mRNA水平高于对照组和n-6 PUFA组,差异均有统计学意义(P0. 05)。结论小鼠肝脏及其血液中脂肪酸构成与其对应的膳食脂肪酸模式一致。不同类型脂肪酸高脂饲料可通过对相关基因的表达影响肥胖状态下肝脏的脂质代谢及脂质沉积。     

10种云南植物油脂肪酸组成比较分析与评价

利用气相色谱法对橡胶籽油、葡萄籽油等10种云南特色植物油的脂肪酸组成进行了分析与评价。结果表明:除了坝子油和青刺果油外,其余8种植物油的不饱和脂肪酸含量均超过80%;SFA与MUFA、PUFA比例接近推荐的膳食脂肪酸比例1∶1∶1的有3种,PUFA与SFA比值大于2的有6种,PUFA的含量较高且n-6 PUFAs与n-3 PUFAs比值小于5的有3种,说明这些植物油都具有很好的开发利用价值。     

膳食脂肪酸构成及适宜推荐比值的研究概况

天然食物中的脂肪酸分为SFA、MUFA和PUFA,PUFA又包含n 6PUFA和n 3PUFA两类,由于它们具有不同的化学结构和物理性状,对健康亦产生不同的影响。大量研究显示,膳食中摄入SFA越高,血清TC越高,CHD发病率越高;膳食脂肪供能34%,MUFA供能18%～21%,可降低血清TC、LDL C、TG,并保持HDL C不降低,橄榄油、茶籽油富含MUFA,但必需脂肪酸不理想;PUFA具有降低血清LDL C水平的作用,玉米胚芽油、葵花籽油富含n 6PUFA,但缺乏n 3系α 亚麻酸以及不适宜的n 6 n 3的比值值得关注;膳食脂肪供能30%以下,SFA、MUFA和PUFA分别供能10%(即1∶1∶1)或<10%∶10%∶10%(<1∶1∶1)仍是目前最佳推荐值;不饱和脂肪酸中n 6 n 3的适宜推荐值是(4～6)∶1。     

蒙古斑点马不同部位脂肪和肌肉组织中脂肪酸组成的比较研究

通过对蒙古斑点马不同部位脂肪和肌肉组织中脂肪酸组成进行分析比较,旨在明确蒙古斑点马体脂脂肪酸组成特点。选择3 匹成年蒙古斑点马,屠宰后采集肾周、肠周和皮下脂肪以及肩肌、背最长肌和臀肌样品,利用气相色谱法测定脂肪酸组成及含量。结果表明：蒙古斑点马不同脂肪组织中均检出19 种脂肪酸,其中饱和脂肪酸（saturated fatty acid,SFA）含量34.77%～37.38%,不饱和脂肪酸（unsaturated fatty acid,UFA）含量达60%以上,UFA中单不饱和脂肪酸（monounsaturated fatty acid,MUFA）含量33.04%～36.39%,多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）含量26.47%～27.51%,其中皮下脂肪C10:0、C18:0、C20:0含量显著低于肾周和肠周脂肪（P＜0.05）;MUFA在皮下脂肪的沉积程度较其他2 个部位高,但均无统计学差异;PUFA中C18:3 n-3含量最高,其在各脂肪组织间无显著差异。3 个不同部位肌肉中均检出15 种脂肪酸,其中SFA含量占总脂肪酸含量的38.32%～40.04%,MUFA含量占35.70%～40.19%,PUFA含量占15.25%～20.33%;SFA中背最长肌和臀肌C12:0含量显著高于肩肌（P＜0.05）,其余SFA在不同部位肌肉间无显著差异;MUFA中背最长肌C16:1含量显著高于肩肌和臀肌（P＜0.05）;肩肌n-6/n-3 PUFA比值显著高于背最长肌和臀肌（P＜0.05）;皮下脂肪的C18:3 n-3和总PUFA含量显著高于背最长肌（P＜0.05）。综上所述,蒙古斑点马不同部位脂肪和肌肉组织脂肪酸组成各具特点,但UFA含量均较高。     

鲟鱼籽酱(Huso dauricus × Acipenser schrenckii)冷藏期间脂肪酸组成的变化

实验通过气相色谱与质谱联用仪(GC-MS),研究了养殖鲟鱼籽酱在冷藏条件(0℃)下脂肪酸组成的变化。结果表明,鲟鱼籽酱脂肪总体组成为:23.03%饱和脂肪酸(SFA),33.68%单不饱和脂肪酸(MUFA)和33.03%多不饱和脂肪酸(PUFA),其富含n-3长链多不饱和脂肪酸,比如EPA(二十碳五烯酸,C20∶5(n-3))和DHA(二十二碳六烯酸,C22∶6(n-3)),营养价值非常高。随着冷藏时间的延长,饱和脂肪酸(SFA)含量显著升高,不饱和脂肪酸(UFA=MUFA+PUFA)含量显著降低,特别是多不饱和脂肪酸降低明显(p0.05),由此表明,仅低温冷藏不能保持鱼籽酱的脂肪酸营养品质。此外,在鲟鱼籽酱贮藏3月后,MUFA和PUFA出现显著性减少,且到贮藏5月时,分别从3月时的36.79、32.43降到34.83、31.86。由此可初步认定为3~5个月为鲟鱼籽酱冷藏时质量控制的关键时间段。     

草鱼肌肉脂肪酸组成及其在冷藏中的含量变化

采用气相色谱-质谱法研究草鱼肌肉脂肪酸组成及其在2～4℃冷藏条件下的变化。结果表明,草鱼肌肉脂肪中不饱和脂肪酸含量较高;饱和脂肪酸(SFA):单不饱和脂肪酸(MLFA):多不饱和脂肪酸(PUFA)的比值为1.08:2.19:1,ω-6/ω-3 PLFA的比值为5.65:1,符合中国营养学会推荐的脂肪酸摄入标准;冷藏过程中,草鱼肌肉总脂肪含量逐渐下降,MUFA和PUFA的相对含量逐渐减少,SFA的相对含量逐渐增多,脂肪酸的降解速率及程度与脂肪酸的不饱和程度呈正相关;脂肪酸的降解与其结构类型有关,ω-3型PUFA降解比ω-6型PUFA更早,但ω-6型PLFA的降解速率更快;部分长链多不饱和脂肪酸(LPUFA)随冷藏时间的延长相对含量略微增加。因此,控制草鱼肌肉脂肪酸在冷藏过程中的降解有利于维持鱼肉制品的营养价值,延长其货架期。     

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。     

海水鱼与淡水鱼omega-3多不饱和脂肪酸含量的比较研究

研究杭州市场常见野生和饲养淡水鱼以及海水鱼omega-3多不饱和脂肪酸（PUFA）的成分及含量。将购买的四个品种淡水鱼（野生和饲养）和六种海水鱼鱼肉去骨切碎,用有机溶剂提取总脂肪,甲酯化后的脂肪酸用气相色谱分离分析。结果表明：总PUFA的含量为从海水刺鲳的37．2mg／100g到淡水野生桂鱼的1821．8mg／100g,其中omeg-3PUFA有C18：3n-3,C18：4n-3,C20：5n-3,C22：5n-3,C22：6n-3,总omega-3PUFA含量为从海水刺鲳的32．3mg／100g到淡水饲养黑鱼的1104．3mg／100g。不同品种鱼脂肪酸含量存在显著性差异（p〈0．001）。结论：野生和饲养淡水鱼以及海水鱼中omega-3PUFA的含量及成分均因品种不同而异,淡水鱼的摄入完全能满足人体日常所需的omega3多不饱和脂肪酸。     

The effects of feeding fish oil on uterine secretion of PGF2alpha, milk composition, and metabolic status of periparturient Holstein cows

The objectives were to determine the effect of dietary fish oil (FO) on uterine secretion of PGF2alpha, milk production, milk composition, and metabolic status during the periparturient period. Holstein cows were assigned randomly to diets containing FO (n = 13) or olive oil (OO, n = 13). Cows were fed prepartum and postpartum diets that provided approximately 200 g/d from 21 d before the expected parturition until 21 d after parturition. The FO used contained 36% eicosapentaenoic acid (EPA, C20:5, n-3) and 28% docosahexaenoic acid (DHA, C22:6, n-3). Blood samples were obtained from 14 d before the due date until d 21 postpartum. A total of 6 FO and 8 OO cows without periparturient disorders were used in the statistical analyses of PGF2alpha-metabolite (PGFM) and metabolite concentrations. Length of prepartum feeding with OO or FO did not differ. Proportions of individual and total n-3 fatty acids were increased in caruncular tissue and milk of cows fed FO. The combined concentrations of EPA and DHA in caruncular tissue were correlated positively with the number of days supplemented with FO. Cows fed FO had reduced concentrations of plasma PGFM during the 60 h immediately after parturition compared with cows fed OO. Concentrations of prostaglandin H synthase-2 mRNA and protein in caruncular tissue were unaffected by diet. Production of milk and FCM were similar between cows fed the two oil diets. However, cows fed FO produced less milk fat. Feeding FO reduced plasma concentrations of glucose. Dietary fatty acids given during the periparturient period can reduce the uterine secretion of PGF2alpha in lactating dairy cows and alter the fatty acid profile of milk fat.     

Developing a strawberry yogurt fortified with marine fish oil

Fortified dairy products appeal to a wide variety of consumers and have the potential to increase sales in the yogurt industry and help increase intake of long-chain n-3 fatty acids. The objectives of this study were to develop a strawberry yogurt containing microencapsulated salmon oil (MSO; 2% wt/vol) and evaluate its characteristics during 1 mo of storage. Unpurified salmon oil (USO) was purified (PSO) and both USO and PSO were analyzed for peroxide value (PV), anisidine value (AV), total oxidation, free fatty acids (FFA), and moisture content. A stable emulsion was prepared with 7% PSO, 22% gum arabic, 11% maltodextrin, and 60% water. The emulsion was spray-dried to produce MSO. The MSO was added to strawberry-flavored yogurt (SYMSO) before pasteurization and homogenization, and a control (SY) without MSO was produced. Both yogurts were stored for 1 mo at 4°C and we determined the quality characteristics including acidity (pH), syneresis, thiobarbituric acid (TBA), fatty acid methyl ester composition, color, and lactic acid bacteria (LAB) count. The entire experiment was replicated 3 times. Total oxidation (unitless) of USO, PSO, and MSO was calculated to be 20.7 ± 1.26, 10.9 ± 0.1, and 13.4 ± 0.25, respectively. Free fatty acid contents were 1.61 ± 0.19%, 0.59 ± 0.02%, and 0.77 ± 0.02% for USO, PSO, and MSO, respectively. Eicosapentaenoic acid and docosahexaenoic acid were the predominant polyunsaturated fatty acids in MSO and in SYMSO, but neither was detected in SY. Fortification of SY with MSO had no significant effect on yogurt pH or syneresis. A decrease in concentration of lactic acid bacteria was observed during the storage of all yogurts. Thiobarbituric acid values significantly increased as storage time increased and SY had a significantly lighter (higher L*) and less yellow (lower b*) color than SYMSO. Although some slight differences were observed in the color and oxidation of SYMSO compared with SY, the study demonstrated that SY could be fortified with salmon oil.     

Uterine,ovarian, and production responses of lactating dairy cows to increasing dietary concentrations of menhaden fish meal

The primary objective was to determine whether the dietary polyunsaturated fatty acids, eicosapentaenoic (EPA, C20:5, n-3) and docosahexaenoic (DHA, C22:6, n-3), present in fish meal (FM) can attenuate uterine secretion of PGF2alpha in response to a challenge with estradiol and oxytocin in lactating dairy cows. Cycling multiparous cows (n = 32) were fed diets containing 0 (OFM), 2.6 (2.6FM), 5.2 (5.2FM), or 7.8% menhaden FM (7.8FM). The diet consisting of 7.8FM also contained fish oil (0.28% of dietary dry matter) to increase intake of EPA and DHA. Average dry matter intake was 24.9 kg/d and unaffected by diet. Combined intakes of EPA and DHA averaged 0, 12.8, 24.1, and 54.0 g/d from the OFM, 2.6FM, 5.2FM, and 7.8FM diets, respectively. At 30 to 34 d after initiation of dietary treatments, cows received an i.m. injection of 100 microg of GnRH followed by i.m. administration of 25 and 15 mg of PGF2alpha after 7 and 8 d, respectively. Synchronous ovulation was induced by an injection of 3000 IU of human chorionic gonadotropin (hCG) given 24 h later on d 9. Subsequent luteal phase increases in plasma progesterone concentrations did not differ (0.88 ng/ml per day). At 15 d after hCG injection, cows were injected with estradiol-17beta (3 mg, i.v.) at 0900 h and oxytocin (100 IU, i.v.) at 1300 h. Plasma PGF2alpha metabolite concentrations after oxytocin injection were reduced in cows fed diets containing FM compared with those fed OFM. Milk production (39.1 kg/d) and concentrations of fat, protein, or urea nitrogen in milk were not affected by diet. Feeding fish meal and fish oil containing eicosapentaenoic acid and docosahexaenoic acid reduced the proportion of n-6 fatty acids and increased that of n-3 fatty acids in milk in a dose-responsive manner.     

Effects of feeding fish meal and n-3 fatty acids on ovarian and uterine responses in early lactating dairy cows

The study was designed to test the effects of dietary supplementation with fish meal or specific n-3 fatty acids on ovarian activity and uterine responses in early lactating cows. From 5 to 50 d in milk (DIM), cows were fed diets that were isonitrogenous, isoenergetic, and isolipidic containing none (control), 1.25, 2.5, or 5% menhaden fish meal (FM) or 2.3% Ca salts of fish oil fatty acids (CaFOFA). Ovarian follicular dynamics were monitored along with plasma concentrations of estradiol and progesterone. Beginning at 23 DIM, cows were induced into a synchronized ovulatory cycle. On d 15 after ovulation (49 DIM), cows were injected with oxytocin and blood samples were collected to monitor uterine release of PGF_2α (measured as 13, 14-dihydro-15-keto PGF_2α; PGFM). Uterine endometrial biopsies were collected for fatty acid analysis and cyclooxygenase-2 (COX-2) protein measurement. Ovarian follicular activities as well as plasma estradiol and progesterone concentrations were similar across diets. Endometrial fatty acid composition of eicosapentaenoic acid (C20:5, n-3) and docosahexaenoic acid (C22:6, n-3) were increased as much as 3-fold by supplementation with fish meal and CaFOFA. Conjugated linoleic acid (C18:2 cis-9, trans-11) in the endometrium was also increased; conversely, arachidonic acid (C20:4, n-6) percentage was decreased by 5% FM. Plasma PGFM response to oxytocin injection was not different among diets and endometrial COX-2 protein abundance did not differ. Results from this experiment demonstrate that dietary supplementation with fish meal or n-3 fatty acids in early lactating dairy cows significantly increased uterine n-3 fatty acid concentrations, but had no apparent effect on endometrial COX-2 or PGF_2α production in response to oxytocin challenge.     

日粮中添加亚麻籽油提高鸡肉中n-3PUFA含量的研究

选择216只21日龄罗斯308商品代肉用母雏,随机分为3组,每组6个重复,每个重复12只鸡.第1组为对照组,在玉米-豆粕型基础日粮上添加5%混合油,处理组分别在基础日粮中添加3%亚麻籽油(2组)和5%亚麻籽油(3组),试验期3周,旨在研究在日粮中添加不同水平的亚麻籽油对鸡肉中n-3PUFA含量和肉鸡生产性能影响.试验结果表明:与对照组相比,3%、5%亚麻籽油组肌肉组织中n-3C18:3、n-3C20:5和n-3PUFA含量显著提高(P＜0.05),n-6/n-3比值显著降低(P＜0.05),n-3C22:6水平则变化不大(P＞0.05).5%亚麻籽油组n-3PUFA总量显著高于3%亚麻籽油组(P＜0.05),n-6/n-3比值低于3%亚麻籽油组(P＞0.05).n-3C18:3在胸肌和腿肌中的沉积量显著高于肝脏(P＜0.05),n-3C20:5、n-3C22:6在胸肌和腿肌中的沉积量显著低于肝脏(P＜0.05).添加3%、5%亚麻籽油对肉鸡生产性能无显著性影响(P＞0.05).以上结果表明,肉鸡饲粮中使用亚麻籽油,可生产出n-3PUFA含量较高,n-6/n-3值较低,对人类健康有益的功能性鸡肉产品.     

高脂日粮中n-6、n-3脂肪酸配比对小鼠机体抗氧化能力及血脂的影响

为了了解不同n-6、n-3系多不饱和脂肪酸配比对小鼠机体抗氧化能力和血脂的影响,通过测定饲喂6周不同饲料C57小鼠血浆中总抗氧化能力(T-AOC)、超氧化物岐化酶(SOD)、丙二醛(MDA)、总胆固醇(TC)、甘油三酯(TC)、高密度脂蛋白胆固醇(HDL)、低密度脂蛋白胆固醇(LDL)和致动脉粥样硬化指数(A11并进行统计分析.实验结果表明,从改善血脂、提高机体抗氧化能力来看,n-6、n-3不饱和脂肪酸比例10:1组效果好于5:1组,若添加抗氧化剂LA,有利于改善机体脂质过氧化产生的不良影响,对预防动脉粥样硬化会起到积极的作用.     

Effect of supplementation with calcium salts of fish oil on n-3 fatty acids in milk fat

Enrichment of milk fat with n-3 fatty acids, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may be advantageous because of their beneficial effects on human health. In addition, these fatty acids play an important role in reproductive processes in dairy cows. Our objective was to evaluate the protection of EPA and DHA against rumen biohydrogenation provided by Ca salts of fish oil. Four Holstein cows were assigned in a Latin square design to the following treatments: 1) ruminal infusion of Ca salts of fish oil and palm fatty acid distillate low dose (CaFO-1), 2) ruminal infusion of Ca salts of fish oil and palm fatty acid distillate high dose (CaFO-2), 3) ruminal infusion of fish oil high dose (RFO), and 4) abomasal infusion of fish oil high dose (AFO). The high dose of fish oil provided ∼16 and ∼21 g/d of EPA and DHA, respectively, whereas the low dose (CaFO-1) provided 50% of these amounts. A 10-d pretreatment period was used as a baseline, followed by 9-d treatment periods with interceding intervals of 10 d. Supplements were infused every 6 h, milk samples were taken the last 3 d, and plasma samples were collected the last day of baseline and treatment periods. Milk fat content of EPA and DHA were 5 to 6 times greater with AFO, but did not differ among other treatments. Milk and milk protein yield were unaffected by treatment, but milk fat yield and DM intake were reduced by 20 and 15%, respectively, by RFO. Overall, results indicate rumen biohydrogenation of long chain n-3 fatty acids was extensive, averaging >85% for EPA and >75% for DHA for the Ca salts and unprotected fish oil supplements. Thus, Ca salts of fish oil offered no protection against the biohydrogenation of EPA and DHA beyond that observed with unprotected fish oil; however, the Ca salts did provide rumen inertness by preventing the negative effects on DM intake and milk fat yield observed with unprotected fish oil.     

Effect of fish oil and canola oil supplementation on immunological parameters,feed intake,and growth of Holstein calves

Supplemental n-3 fatty acids (FA) may support better immune responses than n-6 and n-9 FA in dairy calves. The objective was to evaluate the effect of n-3 FA, supplemented as a fish oil product (FO) in the milk replacer (MR), in comparison to n-6 and n-9 FA, supplemented as canola oil (CO), on body weight (BW), daily gain, and immunological parameters of preweaning Holstein calves. The study was conducted from September to December 2019. Calves were randomly allocated to a control group (n = 15; BW = 36.2 ± 1.5 kg; mean ± SEM) supplemented daily with 30 mL of CO and to an experimental group (n = 15; BW = 36.3 ± 1.5 kg) supplemented with 60 g of a product containing 30 g of FO. Both treatments were added to the MR during the morning feeding. All calves were fed 4 L of MR at 12.5% solids at 0700 and 1600 h for wk 1, 6 L from wk 2 to 7, and 3 L once daily (0700 h) during wk 8 until weaning (56 d). Blood samples were collected at 7, 14, 21, 28, 35, 42, 49, and 56 d of age for serum haptoglobin, TNF-α, IL-1β, and protectin. Dry matter intake was recorded in all experimental calves daily. Seroneutralization titers to vaccination against viral diseases (infectious bovine rhinotracheitis, parainfluenza 3, bovine viral diarrhea, and bovine respiratory syncytial virus) were determined. Mixed models for repeated measures were developed to analyze variables over time. Seroneutralization titers were analyzed by the Kruskal-Wallis test. The other variables were compared by a generalized linear model. Serum FA profile at 35 d of age showed that FO supported higher concentrations of n-3 FA than CO. Final BW [65.2 vs. 62.0 kg, standard error of the mean (SEM) = 2.1 kg] and average daily gain (0.52 vs. 0.46 kg/d, SEM = 0.1 kg/d) tended to be higher for the FO than the CO group. An interaction of treatment × day for dry matter intake was observed, especially during weaning (2.17 kg vs. 1.94 kg, SEM = 0.158 kg, for FO and CO group, respectively). Blood lactate (mmol/L) was higher in the CO than in the FO group at d 7. Haptoglobin and IL-1β were higher for the CO group on d 14 than the FO group. The TNF- α concentrations for the FO group were reduced over time, whereas the concentrations in the CO group remained constant. Protectin was higher in the FO group on d 14, but was lower on d 28, 35, and 49. Seroneutralization antibody titers postvaccination for the PI₃ virus were higher for the FO than the CO group. In conclusion, calves supplemented with FO had lower concentrations of blood lactate, haptoglobin, IL-1β and TNF-α than calves supplemented with CO during the study period. The FO supplementation had a higher DMI than CO supplementation. Results of this trial should be interpreted with caution due to the lack of a negative control group as well as the lower birth weight and growth rate observed under heat stress conditions.