共轭亚油酸对猪免疫功能的影响

共轭亚油酸（Conjugated Linoleic Acid, CLA）属于多不饱和脂肪酸,是必需脂肪酸亚油酸的一组异构体。CLA 具有抗肿瘤、抗动脉粥样硬化、抗糖尿病、减少脂肪沉积、增强免疫机能和促生长等广泛的生物学作用。文章综述了共轭亚油酸对猪免疫机能的作用,为进一步开发和利用共轭亚油酸提供依据。     

反刍动物体内CLA的形成及其影响因素

共轭亚油酸（CLA）是一种主要从反刍动物脂肪及其奶产品中发现的天然活性物质.一些多不饱和脂肪酸（主要是亚油酸和亚麻酸）在反刍动物瘤胃内通过异构化和生物脱氢反应形成CLA;另外,反式油酸在动物细胞内经Δ9-脱氢酶的脱氢作用也能形成CLA.c9,t11-CLA是反刍动物脂肪中CLA的主要异构体,其在乳脂中占80%～90%,在肉中要稍低.多种自然因素,人工手段能够影响反刍动物体内CLA含量.     

植物乳杆菌对提高发酵牛乳中共轭亚油酸含量的研究

利用植物乳杆菌(Lactobacillus plantarum) LT2-6发酵添加亚油酸(LA)的脱脂牛乳,转化LA生成共轭亚油酸(CLA),以期提高发酵牛乳中的CLA含量。结果表明：LA诱导可提高发酵牛乳中的CLA产量,发酵温度37℃,CLA生成量和LA转化率为最高。加入葡萄糖、酪蛋白酶水解物,有助于植物乳杆菌LT2-6的生长和提高CLA的生成量。添加0.075％的LA,发酵24 h,43％的LA转化为CLA,发酵后牛乳中的CLA含量达到320 μg/mL,为普通发酵牛乳的5～6倍。经脂肪酸萃取和甲酯化,气相色谱检测显示生成的CLA主要为：cis-9,trans-11-CLA。     

日粮中添加CLA对鹌鹑蛋品质和蛋黄脂肪酸组成的影响

通过在日本鹌鹑日粮中添加共轭亚油酸(CLA),研究CLA对鹌鹑的蛋品质、蛋黄中的脂肪酸组成、n-6系列和n-3系列多价不饱和脂肪酸的比率(n-6/n-3)以及胆固醇含量的影响。试验将180只8周龄鹌鹑按单因子设计随机分为4组,分别在CP 20%日粮中添加0,0.25%,0.5%及1.0%CLA,试验期为20周。结果表明:与对照组相比,蛋黄中C18:3和二十二碳六烯酸(DHA C22:6)的含量显著增加(P<0.05);亚油酸(C18:2)的含量差异不显著(P>0.05);花生四烯酸(C20:4)含量和n-6/n-3比率显著降低(P<0.05)。蛋黄中胆固醇含量随CLA添加量的增加有下降的倾向,试验开始14 d后0.5%、1.0%添加组与对照组相比显著下降(P<0.05)。蛋黄中脂肪酸C18:3含量与CLA添加比率间关系为Y=3.882 3X+0.08(r=0.619 1),日粮中CLA适宜的添加量为0.9%。     

鱼油对瘤胃培养液中共轭亚油酸和氢化中间产物累积的影响

试验采用批次培养法研究了体外条件下添加鱼油对山羊瘤胃培养液中共轭亚油酸及氢化中间产物累积规律的影响,鱼油的添加量为50 mg·瓶-1.结果表明,鱼油组c9,t11-CLA含量始终显著高于对照组(P＜0.05),且在培养8 h含量达到最高,为6.05 mg·g-1干物质;t10,c12-CLA含量低于对照组,但是差异不显...     

沙葱提取物对绵羊消化道乳酸菌产共轭亚油酸(CLA)含量的影响

本文选择了4只瘘管蒙古羯羊,通过在绵羊日粮中添加沙葱提取物,采集瘤胃液和食糜,分离和筛选乳酸菌,添加亚油酸培养来研究沙葱提取物对绵羊消化道乳酸菌产共轭亚油酸(CLA)含量的影响。结果表明,沙葱提取物显著提高绵羊瘤胃和十二指肠中乳酸菌的数量和CLA的含量,且十二指肠中的大于瘤胃中的。这为进一步调控绵羊瘤胃内环境,提高羊肉中CLA含量打下基础。     

牛奶脂肪酸及CLA的分析方法的改进

采用完全随机区组试验设计,针对四种不同的牛奶脂肪酸分析方法,按牛奶样品来源分为2个区组,即区组I为8头奶牛个体按每天早、中、晚产奶量加权后的混合样;区组II为60头牛早上挤完奶的混合样,每组16个重复。由于不同CLA异构体间的生物学效果不同,采用常规的气相分离柱(60m)不能完全区分CLA异构体。因此,以Kelly等[1]和Palmquist[2]方法为参照,在利用离心方法和离心加有机溶剂分离乳脂肪并结合酸碱混合甲酯化的基础上,利用进口安捷伦公司HP6890N气相色谱仪结合100m长硅胶毛细管柱(HP2560),采用通过程序升温,气相检测结果表明,该方法能够对乳中常规脂肪酸及其CLA异构体(4种)进行区分,不仅对于乳脂大部分脂肪酸组成没有显著的影响,同时能弥补乳脂肪提取时存在耗时、工作量大、环境污染、成本高和处理效率低的缺陷。该分析方法每天可以预处理300个牛奶样品,能极大地提高分析效率。     

费氏丙酸杆菌谢氏亚种和植物乳杆菌中亚油酸异构酶的分离纯化

采用盐析、Sephacryl S-200HR凝胶过滤层析、DEAE Sepharose F.F.离子交换层析相结合的方法,分别建立了来源于费氏丙酸杆菌谢氏亚种（P. feudenreichii ssp. shermanii）和植物乳杆菌（L. plantarum）的亚油酸异构酶的分离提取步骤。结果表明不同来源的亚油酸异构酶在纯化的过程中表现出不同的洗脱特性,P. freudenreichii ssp. shermanii亚油酸异构酶的分子质量约为56 kDa, L. plantarum亚油酸异构酶的分子质量为50.65 kDa。不同来源亚油酸异构酶的分离纯化方法存在差异。     

Relationships between the contents of vaccenic acid, CLA and n − 3 fatty acids of goat milk and the muscle of their suckling kids

The relationship between goat milk fatty acid composition, especially trans-11 C18:1 (vaccenic acid, VA), conjugated linoleic acid (CLA) and n − 3 fatty acids, and that of the meat from their suckling kids was investigated by feeding the dams a diet supplemented with whole cottonseed (COT) or extruded linseed (LIN). Fifteen Sarda goats, fed 1.2 kg/day per head of concentrate and hay ad libitum, were divided into two groups and supplemented during weeks 4 and 5 post-partum with 32 g/day per head of fat from LIN and COT, which have high C18:3 and C18:2 content, respectively. Fifteen kids were fed exclusively by suckling maternal milk until slaughtering (at 9–10 kg of body weight and approximately 6 weeks of age). Twenty-four hour after slaughter, the longissimus dorsi (LD) muscle was removed from each carcass. Fatty acid profiles of milk and LD were significantly affected by diets. Compared to COT, feeding LIN changed the milk fatty acid profiles by decreasing the proportion of C16:0 and increasing the contents of VA, C18:3 n − 3 (linolenic acid) and total CLA, including cis-9, trans-11-, trans-11, cis-13-, trans-11, trans-13- and trans, trans isomers. The concentrations of VA, cis-9, trans-11 C18:2 (rumenic acid, RA) and linolenic acid in milk and those in kid muscle were strongly correlated. The fatty acid profile of meat from suckling kids was effectively modified by manipulating the diet of the dams.     

The effects of diet and age on serum complement system activity in goat kids

Thirty new born male kids were allotted into three groups to evaluate the effects of diet and age on complement system activity in serum. After the colostrum feeding period, the control group (C) received a commercial milk replacer; the CLA group received 20 g/kg milk replacer DM of conjugated linoleic acid; and the GMK group was fed with goat milk. The kids were fed colostrum for 2 days and then either milk replacer or goat milk from days 3 to 60. Blood samples were taken at 1, 10, 20, 30, 40, 50 and 60 days of age. The complement system activity was higher (P < 0.05) in the GMK group throughout the whole experiment through alternative pathway. C kids did not present complement activity at any time. CLA group complement activity was statistically higher than that of C kids from 30 to 60 days, through alternative pathways. In conclusion, the milk replacer formula should be reformulated because it did not induce any complement system activity in the first two months of life.