The intravenous bile Acid loading test in the goat: determination of a procedural protocol and reference values

An intravenous bile acid loading test was performed on 16 goats using various dosages and sampling protocols. A recently developed enzymatic bile acid assay provided an economical and technologically simple method for bile acid analysis. Intravenous injection of bile salts into goats was well tolerated. Clearance times were rapid. A protocol for performance of the test was suggested and a practical reference range for T 1/2 clearance of 4+/-1 minute was determined. Further investigations of this test in the assessment of liver function in the ruminant appear warranted.     

Expression of peroxisome proliferator-activated receptor α in rat fatty liver

AIM:To investigate the role of expression of peroxisome proliferator-activated receptor α(PPAR α) in pathogenesis of rat fatty liver.METHODS:The rats were treated with a low dose of carbon terachloride (CCl₄) and fed a high fat diet to produce fatty liver. We determined the concentrations of triglyceride (TG), total cholesterol (TC), free fatty acid (FFA) in liver and the alanine aminotransferase (ALT) activity, tumor necrosis factor-α (TNF-α), FFA in serum and the degree of hepatocytic steatosis. Total RNA of liver was extracted, and the expression of PPAR α were analyzed by semi-quantitative RT-PCR method.RESULTS:In model group, the hepatocytic PPAR α mRNA expression decreased to 0.41±0.28, compared to 1.41±0.29 in the control group (P＜0.01). The contents of TG, TC, FFA in model rat liver were (1.88±0.20) mmol·L^-1, (11.03±1.12) mmol·L^-1 and (1 260.38±151.27) μmol·L^-1, respectively, compared to (0.53±0.10) mmol·L^-1, (1.25±0.25) mmol·L^-1 and (334.30±27.09) μmol·L^-1 in the control group (P＜0.01). The activity of ALT, concentrations of TNF-α and FFA in serum were also increased remarkably in model group.CONCLUSION:Oxidation of fatty acid and utilization of lipids in liver are affected by reducing the expression of PPAR α, which result lipid accumulation in liver.     

低氧条件下的冲刺训练对运动员生理生化指标的影响*

目的：研究低氧条件下的冲刺训练对运动员身体内葡萄糖、胰岛素、游离脂肪酸以及乳酸应激条件下的影响。方法：所有运动员都分别参加三组不同实验条件的训练,并且每组训练相隔7天。三组不同训练条件分别为：常氧压的冲刺运动（N组）;中等缺氧的冲刺运动（M组）;高度缺氧的冲刺运动(H组)。每组冲刺运动都在功率自行车上进行,每组运动为4次为时30s的冲刺运动,阻力都为10档,并辅以教练口头激励,每次冲刺运动后恢复6min,并记录每次运动员产生的最高功率以及平均功率。两种不同的低氧条件由低氧面具提供。训练后,分别在运动前抽取血液1次,以及在4次运动完成后5min,30min,60min,120min各取一次,并检测各项指标。结果：1.常氧压组与两组低氧压组相比,血细胞中的葡萄糖含量没有明显的差异,但是,与没有进入运动开始前相比较,冲刺运动后的5min内葡萄糖含量上升显著。2.只有在冲刺运动完成后2h后,体内脂肪酸含量才显著上升,并且与常氧压组和中等低氧压组相比较,高度缺氧组的游离脂肪酸上升更为明显,且与这两组差异显著。3.与运动开始前相比,运动后5min、30min、60min内体内乳酸含量高,且具有显著差异。但在120min后差异消失。4.运动结束后5min时体内胰岛素含量较高,且与开始运动前和运动结束后其他三个时间段相比,具有显著差异。     

Fat and fatty acid digestibility of different fat sources in growing pigs

The effect of fat source on fat and fatty acid (FA) apparent faecal (aFD) and ileal digestibility (aID) was studied in growing pigs. Faecal and ileal digestibilities were measured, using titanium dioxide as inert marker, in intact and ileo-rectally anastomosed pigs, respectively. Five different fat sources, added at 10% to a barley based diet (B), were tested: tallow (T), high oleic sunflower oil (HOSF), sunflower oil (SO), linseed oil (LO) and a fat blend (FB; 5.5% T, 3.5% SO and 1% LO of diet).

Except for B and T, fat aFD and aID were relatively similar among diets and site of measurements and the same was observed when it was obtained from the sum of FA aFD. However fat and sum of FA aID varied according to dietary FA composition and it was inversely related with the saturated FA content, due to the lowest aID of palmitic and stearic. aID of linoleic in SO and linolenic in LO were higher than the respective FA of the other diets and no differences were observed for oleic acid. The aFD of the unsaturated FA was higher than the corresponding aID values, despite similar fat aID and aFD. This together with the lower (in some cases negative) aFD of stearic acid suggest that there is biohydrogenation of unsaturated FA in the hindgut. Measurement at the end of the ileum should give a better estimation of digestibility of fat and FA than at the faecal level.     

Branched‐chain amino acid ratios in low‐protein diets regulate the free amino acid profile and the expression of hepatic fatty acid metabolism‐related genes in growing pigs

Liver metabolism is affected by nutrients. The aim of this study was to explore the effects of low‐protein diets (17% crude protein, CP) supplemented with branched‐chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile) and valine (Val), on hepatic amino acid profile and lipid metabolism in growing pigs. The ratio of Leu : Ile : Val in all groups was 1 : 0.51 : 0.63 (20% crude protein, CP), 1 : 1 : 1 (17% CP), 1 : 0.75 : 0.75 (17% CP), 1 : 0.51 : 0.63 (17% CP) and 1 : 0.25 : 0.25 (17% CP) respectively. Results revealed that compared to the positive control group (1 : 0.51 : 0.63, 20% CP), the low‐protein diets significantly augmented the concentrations of most essential amino acids and non‐essential amino acids (p < .05), with the greatest values observed in the 1 : 0.25 : 0.25 group. Moreover, relative to the control, the low‐protein diets with the Leu : Ile : Val ratio ranging from 1 : 0.75 : 0.75 to 1 : 0.25 : 0.25 markedly downregulated the mRNA abundance of acetyl‐CoA carboxylase (ACC), lipoprotein lipase (LPL) and fatty acid‐binding protein 4 (FABP‐4) (p < .05), and upregulated the mRNA expression of hormone‐sensitive lipase (HSL), peroxisome proliferator‐activated receptor‐g coactivator‐1α (PGC‐1α), uncoupling protein 3 (UCP3) and liver carnitine palmitoyltransferase 1 (L‐CPT‐1) (p < .05). Therefore, our data suggest that protein‐restricted diets supplemented with optimal BCAA ratio, that is, 1 : 0.75 : 0.75–1 : 0.25 : 0.25, induce a shift from fatty acid synthesis to fatty acid oxidation in the liver of growing pigs. These effects may be associated with increased mitochondrial biogenesis.     

添加不饱和脂肪酸对酿酒酵母胞内脂肪酸成分和葡萄酒香气的影响

【目的】研究葡萄汁中不饱和脂肪酸（Unsaturated fatty acids,UFAs,包括油酸、亚油酸和α-亚麻酸）含量同时变化对葡萄酒发酵过程中酿酒酵母胞内脂肪酸成分和酿酒香气的影响,为提高葡萄酒品质提供参考。【方法】选用‘美乐’葡萄（Vitis vinifera L.）汁为培养基,试验设置对照组（不添加UFAs,CK）、低浓度UFAs添加组（LFG）和高浓度UFAs添加组（HFG）,比较葡萄酒酒精发酵过程中3个处理组间酵母（Saccharomyces cerevisiae EC1118）生长（OD₆₀₀）、细胞内脂肪酸成分以及酿酒香气成分的差异。【结果】提高UFAs浓度能够促进酵母细胞生长以及对UFAs的吸收,使胞内UFAs含量迅速增加,但抑制饱和脂肪酸（C4:0-C24:0）的合成。分析UFAs对葡萄酒香气物质的影响发现,高浓度UFAs能够促进酵母高级醇和乙醇酯类（包括己酸乙酯、辛酸乙酯和癸酸乙酯）香气的产生,但抑制了中短链脂肪酸（medium-chain fatty acids,MCFAs,C4:0-C12:0）的产生,对来源于葡萄果实的醛类、单萜和降异戊二烯香气的影响较小。【结论】提高葡萄汁初始UFAs含量能够促进细胞生长,提高葡萄酒发酵速度,有利于乙醇酯类香气物质的合成,从而增强葡萄酒的果香、花香和甜香特征。因此,调控葡萄或葡萄汁中不饱和脂肪酸浓度可以作为调控葡萄酒香气品质的一种重要手段。     

Oil content and fatty acid composition of promising IndianBrassica campestris L. (Toria) genotypes

Seeds of sixty four genotypes ofBrassica campestris L. (Toria) were analyzed for oil content and fatty acid composition. Oil content varied from 38.9% to 44.6%. Major fatty acids viz. oleic, linoleic, linolenic, eicosenoic and erucic acids exhibited ranges from 10.1% to 17.3%, 5.9% to 14.5%, 5.2% to 15.0%, 7.7% to 13.7% and 39.6% to 59.9%, respectively. Compared to the standard cultivar ITSA, four genotypes contained 5 to 8% lower content of erucic acid; and six genotypes contained significantly higher content of linoleic acid. Oil was positively correlated with erucic acid. The observed inverse relationship between linoleic and erucic acid contents might be utilized in breeding nutritionally better Toria cultivars with both high linoleic and low erucic acid contents.     

Effects of incremental amounts of fish oil on trans fatty acids and Butyrivibrio bacteria in continuous culture fermenters

Previous studies have shown that adding fish oil (FO) to ruminant animal diets increased vaccenic acid (VA; t11 C18:1) accumulation in the rumen. Therefore, the objective of this study was to evaluate the effect of dietary FO amounts on selected strains of rumen bacteria involved in biohydrogenation. A single‐flow continuous culture system consisting of four fermenters was used in a 4 × 4 Latin square design with four 9 days consecutive periods. Treatment diets were as follows: (i) control diet (53:47 forage to concentrate; CON), (ii) control plus FO at 0.5% (DM basis; FOL), (iii) control plus FO at 2% (DM basis; FOM) and (iv) control plus FO at 3.5% (DM basis; FOH). Fermenters were fed treatment diets three times daily at 120 g/day. Samples were collected from each fermenter on day 9 of each period at 1.5, 3 and 6 h post‐morning feeding and then composited into one sample per fermenter. Increasing dietary FO amounts resulted in a linear decrease in acetate and isobutyrate concentrations and a linear decrease in acetate‐to‐propionate ratio. Propionate, butyrate, valerate and isovalerate concentrations were not affected by FO supplementation. Concentrations of C18:0 in fermenters linearly decreased, while concentrations of t10 C18:1 and VA linearly increased as dietary FO amounts increased. The concentrations of c9t11 and t10c12 conjugated linoleic acid were not affected by FO supplementation. The DNA abundance for Butyrivibrio fibrisolvens, Butyrivibrio vaccenic acid subgroup, Butyrivibrio stearic acid subgroup and Butyrivibrio proteoclasticus linearly decreased as dietary FO amounts increased. In conclusion, FO effects on trans fatty acid accumulation in the rumen may be explained in part by FO influence on Butyrivibrio group.     

氧调控下人工湿地微生物群落结构变化研究

运用磷脂脂肪酸(PLFAs)技术研究了氧调控下复合垂直流人工湿地(IVCW)微生物群落结构及活性变化,结果表明,不曝气IVCW基质表层以好氧微生物为优势种群,但绝大部分微生物都集中在0～20cm基质层,系统的净化空间受到限制;氧调控下微生物群落向基质纵深发展,表征好氧微生物的单不饱和脂肪酸的含量显著增加,曝气系统下行池表层各类群微生物的生物量为不曝气系统的2～6倍,表征微生物活性的PLFAs总不饱和度水平也明显升高;革兰氏阴性细菌成为曝气IVCW基质微生物群落的优势种群,群落具有更高的活性和专一性,提高了污染物的去除效果。因此,进一步研究微生物的这种适应机制可以为优化湿地系统提供一定的理论基础。     

种青养鱼模式下的草鱼肌肉营养成分和品质特性

为探究种青养鱼养殖模式对草鱼肌肉营养成分和品质特性的影响,随机选取以种青喂草为主养殖模式下养殖的草鱼(生态草鱼)和投喂人工配合饲料进行养殖的草鱼(饲料草鱼)各16尾,测定其肌肉系水力和质构特性指标,以及肌肉常规营养成分、矿物元素、氨基酸和脂肪酸含量。结果显示,生态草鱼和饲料草鱼肝体比和空壳率无显著性差异;生态草鱼肌肉系水力指标中滴水损失显著低于饲料草鱼,冷冻渗出率不显著地低于饲料草鱼,失水率不显著地高于饲料草鱼,p H值无显著性差异;肌肉的硬度、弹性、凝聚性、胶黏性和回复性均无显著性差异;生态草鱼粗脂肪含量显著低于饲料草鱼,水分、灰分、粗蛋白含量均无显著性差异;生态草鱼P和Fe含量均显著高于饲料草鱼,Mg、Mn和Cr含量均极显著高于饲料草鱼;生态草鱼和饲料草鱼肌肉氨基酸组成基本一致,均含有17种氨基酸,其中人体必需氨基酸总量分别为6.85%和6.27%。生态草鱼必需氨基酸指数(EAAI)为76.07,而饲料草鱼为77.29,饲料草鱼略高于生态草鱼。生态草鱼和饲料草鱼肌肉均含19种脂肪酸,其中棕榈酸、花生四烯酸(ARA)、亚油酸(LA)、油酸、二十二碳六烯酸(DHA)和硬脂酸含量较高,为主要脂肪酸,而花生五烯酸(EPA)+DHA含量分别为8.95%和10.70%,且差异显著。研究表明,生态草鱼和饲料草鱼在肌肉质构特性方面无显著性差异,与饲料草鱼相比,生态草鱼具有肌肉系水力强、低脂肪和矿物元素含量高的特点。