Influence of exogenous application of n-3 fatty acids on meat quality, lipid composition, and oxidative stability in pigs.

The effect of dietary n-3 fatty acids on the fatty acid composition and lipid peroxidation of different tissues in pigs were studied. 20 castrated male pigs were included in this investigation, one half was fed daily a diet containing 1.3 g n-3 fatty acids/kg diet (control) and 10 pigs were fed a diet containing 14 g n-3 fatty acids/kg diet (n-3 diet) at the growing-finishing period. The intake of dietary n-3 fatty acids increased the concentration of these fatty acids in backfat, and the neutral and polar fractions of skeletal muscle and heart homogenates. The polar fraction showed an increased relative concentration of n-3 fatty acids in comparison to control, while the n-6 fatty acid content was reduced. In heart homogenates there was an enlargement of n-3 fatty acids both in polar lipids and in neutral lipids whilst n-6 fatty acids were decreased. Feeding n-3 fatty acid enriched diet had no influence on meat quality parameters drip loss, meat colour or pH value. The lipid peroxidation (measured as malondialdehyde equivalents) was in the order liver > heart > skeletal muscle with higher values in the n-3 group. However, by stimulation of oxidation by Fe2+/ascorbate for 3 hours the order of oxidative products in the n-3 group was muscle > liver > heart, whereas in the control group the order was liver > heart = muscle. Summarized, feeding a highly n-3 fatty acid enriched diet caused an incorporation of these fatty acids and increased the susceptibility to peroxidation in all investigated tissues.     

复合植物精油对脂多糖刺激仔猪肝脏的保护作用

试验旨在研究复合植物精油(OCT)对脂多糖(LPS)刺激仔猪肝脏的保护作用。选取18头仔猪,随机分为对照组、LPS组和OCT+LPS组,每组6个重复。对照组与LPS组饲喂基础日粮,OCT+LPS组在基础日粮中添加50 mg/kg OCT。试验期21 d。于试验第21天,LPS组与OCT+LPS组仔猪腹腔注射LPS,对照组注射等量的生理盐水,3 h后采血,6 h后屠宰。结果表明:与对照组相比,LPS刺激提高了血浆谷丙转氨酶(ALT)、谷草转氨酶(AST)、碱性磷酸酶(ALP)、谷酰转肽酶(GGT)、肝脏诱导型一氧化氮合酶(i-NOS)的活力(P0.05),肝脏热休克蛋白70(HSP70)基因的相对表达量显著提高(P0.05);仔猪肝脏表皮生长因子(EGF)、白细胞介素10(IL-10)、胰岛素样因子(IGF-1)、丝氨酸蛋白激酶(mTOR)基因的相对表达量显著降低(P0.05)。在日粮中添加50 mg/kg的OCT,可缓解LPS导致的仔猪血浆ALT、AST、GGT活力的升高以及肝脏i-NOS活力的升高(P0.05),且有缓解LPS导致的仔猪肝脏MPO活力升高的趋势(P0.1),另外可缓解LPS导致的仔猪肝脏HSP70基因相对表达量的升高以及EGF、IL-10、IGF-1、mTOR等基因相对表达量的降低(P0.05)。综上可知,日粮中添加50 mg/kg的OCT可缓解LPS刺激引起的肝脏炎症反应,提高仔猪肝脏细胞的生长和增殖,进而缓解LPS刺激导致的仔猪肝脏氧化应激损伤。     

风柜斗草提取物通过调控脂质代谢改善小鼠肝脂质沉积症

旨在探究风柜斗草提取物(Sarcopyramis napalensis Wall extract,SNE)对蛋氨酸胆碱缺乏(MCD)饮食诱导的肝脏脂质沉积的作用与机制。本研究将60只雄性C57BL/6小鼠随机分为6组,每组10只,设置MCS组(MCD饲料的对照饲料组)、MCS+风柜斗草提取物组(400 mg·(kg·bw)^-1)、MCD组、MCD+风柜斗草提取物低、中、高剂量组(100、200、400 mg·(kg·bw)^-1),造模及药物干预6周。进行肝组织切片HE染色、天狼猩红染色,检测血清碱性磷酸酶(AKP)、谷草转氨酶(AST)、谷丙转氨酶(ALT),肝组织谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活力水平及丙二醛(MDA)含量以评估肝脂质沉积、肝纤维化以及肝抗氧化情况。使用Western blot技术检测腺苷酸激活蛋白激酶(AMPK)蛋白的激活情况,使用qRT-PCR技术检测固醇调节元件结合蛋白-1C (SREBP-1c)、肝型脂肪酸结合蛋白(L-FABP)、脂肪酸转运蛋白-3(FATP-3)、脂肪酸转运蛋白-4(FATP-4)、细胞间黏附分子-l (ICAM-1)、血管细胞黏附分子-l (VCAM-1)、基质金属蛋白酶-2(MMP-2)、组织金属蛋白酶抑制剂-2(TIMP-2) mRNA表达水平,同时采用LC-MS/MS技术进行肝组织非靶向脂质组学分析。结果表明,给予200、400 mg·(kg·bw)^-1剂量的风柜斗草提取物时均可显著改善MCD饲料饲喂的小鼠肝脂肪变性,减少炎症簇以及肝纤维化程度。给予风柜斗草提取物100、200、400 mg·(kg·bw)^-1时均可显著降低MCD饲料饲喂的小鼠血清中ALT和AKP的活力以及肝组织中MDA的含量,显著提高小鼠肝中GSH-Px的活力。Western blot及qRT-PCR检测结果显示,风柜斗草提取物显著激活MCD饲料饲喂的小鼠肝组织AMPK;显著抑制MCD饲料饲喂的小鼠肝组织SREBP-1c、L-FABP、FATP-3、FATP-4、ICAM-1、VCAM-1、MMP-2、TIMP-2的mRNA表达水平。肝脂质组学检测结果显示,风柜斗草提取物显著降低MCD饲料饲喂的小鼠肝中甘油三酯(TG)、磷脂酰甘油(PG)以及神经酰胺(Cer)的相对含量;显著提高鞘磷脂(SM)以及辅酶Q9相对含量。结果提示,风柜斗草提取物可通过AMPK/SREBP-1c途径抑制TG合成,以及通过抑制FATP与L-FABP表达来减少肝对脂肪酸的摄取,从而改善MCD饲料饲喂的小鼠肝脂肪变性;通过提高MCD饲料饲喂的小鼠肝组织中SM和辅酶Q9相对含量以及降低Cer相对含量,改善肝细胞氧化应激损伤情况,进而改善MCD饮食诱导的小鼠肝炎症和纤维化,最终达到改善肝脂质沉积症的作用。     

肥肝鹅恢复期血液生化指标、肝脏常规营养成分及脂代谢相关基因表达水平的变化研究

试验旨在研究朗德鹅填饲形成肥肝及恢复后其体重、肝脏重、腹脂重、常规营养成分、血液生化指标和肝脏中与脂代谢相关基因的表达变化情况,为进一步阐明鹅肥肝的恢复或保护机制提供依据。将18只70日龄朗德鹅随机分为3组(每组6只):组1为对照组,用玉米饲料进行常规饲喂;组2为填饲组,填饲玉米饲料19 d;组3为填饲19 d后再用玉米饲料常规饲养20 d进行肝脏恢复。结果显示,与组2相比,组3鹅体重、肝脏重均极显著降低(P<0.01),而腹脂重下降不显著(P>0.05);与组2相比,组3肝脏水分、灰分和粗蛋白质均显著上升(P<0.05),而粗脂肪含量显著下降(P<0.05),但与组1相比,除水分外,各项指标均无显著变化(P>0.05);与组2相比,组3血浆中谷丙转氨酶(ALT)、谷草转氨酶(AST)、甘油三酯(TG)和高密度脂蛋白胆固醇(HDL-C)浓度与组2相比均显著下降(P<0.05),但与组1相比,均无显著差异(P>0.05);与组2相比,组3肝脏中脂肪酸脱氢酶(FADS1)、硬脂酰辅酶A去饱和酶(SCD1)和细胞色素P450 2C45(CYP2C45)基因的表达量均显著下降(P<0.05),但与组1相比均无显著变化(P>0.05)。综上所述,本研究从不同层面揭示了鹅肥肝的可逆性,为深入研究鹅肥肝的恢复或保护机制,促进动物脂肪肝问题的解决奠定了基础。     

Study on Changes of Blood Chemistry Indexes,Hepatic Routine Nutritional Composition and Expression of Lipid Metabolism-associated Genes during the Recovery of Geese with Fatty Livers

This experiment aimed to determine the changes of body weight, liver weight, abdominal fat weight, hepatic routine nutritional composition, blood biochemistry indexes, as well as mRNA expression of lipid metabolism-associated genes during the recovery of Landes geese with fatty liver, which provided the basis for the further elucidation of the recovery or protection mechanism of goose fat liver.18 Landes geese were divided into three groups (6 gees in each group).Group 1 was control group, in which the geese were fed with boiled maize;Group 2 was the overfeeding group without recovery, in which the geese were overfed with a maize-based diet for 19 days;And group 3 was the overfeeding group with 20-day recovery, in which the geese were overfed with the maize-based diet for 19 days followed by feeding boiled maize for 20-day recovery.The results showed that compared with group 2, the body weight and liver weight of the geese in group 3 decreased extremely significantly (P<0.01), and the abdominal fat weights undecreased significantly (P>0.05);Moreover, the percentages of nutrients including water, ash, CP of livers in group 3 increased significantly (P<0.05), while the percentage of EE decreased significantly (P<0.05), but there were no significant difference for these variables between groups 1 and 3 (P>0.05) except water.In regard to blood biochemistry indexes, the contents of blood ALT, AST, TG and HDL-C in group 3 decreased significantly (P<0.05), but there were no significant difference from those of group 1 (P>0.05).The mRNA expression levels of FADS1, SCD1 and CYP2C45 in group 3 decreased significantly compared with group 1 (P<0.05), but there were no significant difference between groups 1 and 3 (P>0.05).In summary, this study demonstrated the recoverability of goose fatty liver at different layers, and thus laid a foundation for further investigation on the recovery or protective mechanism of goose fatty liver and found the solution to resolve the problems related to animal fatty liver.     

Pathologic features of polybrominated biphenyl toxicosis in the rat and guinea pig.

Young male rats were fed a diet containing 0, 1, 10, 100, or 500 ppm of a commercial mixture of polybrominated biphenyls (PBB) that had been accidentally incorporated into a mineral mixture and fed to Michigan livestock and poultry. After 30 days, 9 of the 12 rats in each group were killed and tissues were examined. Liver weight to body weight ratios were significantly increased at all feeding levels; at 500 ppm, liver weight had more than doubled. Kidney weight was not affected. Microscopic lesions were mostly confined to the liver and consisted of extensive swelling and vacuolation of hepatocytes in rats fed diets containing 100 and 500 ppm of PBB. Slight swelling and vacuolation were seen in rats fed the diet containing 10 ppm, and lesions were not found at 0 or 1 ppm. There was a significant increase in hepatic mitochondrial size at 1 ppm, and smooth endoplasmic reticulum was markedly increased at 100 and 500 ppm. Myelin bodies were present at 100 and 500 ppm, and vacuoles were numerous. Rats killed at 60 days had similar lesions. The activity of hepatic microsomal enzymes increased at all levels of feeding of PBB. Rat pups nursing dams fed a diet containing 10 ppm of PBB had microscopic and ultrastructural hepatic lesions. When guinea pigs were fed PBB at the same amounts as were rats, the results were strikingly different. Guinea pigs fed a diet containing 500 ppm of PBB died within 15 days; at 100 ppm, only 2 of 6 survived for 30 days. Effects on liver weight were inconsistent, but 2 of 6 fed a diet containing 10 ppm had enlarged livers.     

土庄绣线菊水浸液对小鼠急性酒精肝损伤保护作用的研究

本试验旨在研究土庄绣线菊水浸液对小鼠急性酒精肝损伤的保护作用。将试验小鼠随机分为低剂量组、中剂量组、高剂量组、模型组和空白组5组。采用一次酒精灌胃法建立急性酒精性肝损伤小鼠模型。建模后,测定各小鼠肝组织谷胱甘肽(GSH)与丙二醛(MDA)含量及血清中冬氨酸氨基转移酶(AST)和丙氨酸转移酶(ALT)的活性,并进行肝组织病理切片观察。结果显示,土庄绣线菊水浸液能够明显降低酒精性肝损伤引起的AST和ALT活性的升高,能有效保持肝脏中GSH含量和明显降低MDA含量,说明土庄绣线菊水浸液对乙醇所致肝损伤具有保护作用,能明显改善酒精引起的肝脏损害。     

亚麻籽和鱼油对蛋鸡蛋黄n-3多不饱和脂肪酸含量与肝脏脂肪酸代谢的影响

本试验旨在研究饲粮中添加亚麻籽和鱼油对蛋鸡蛋黄n-3多不饱和脂肪酸含量、肝脏脂肪酸组成及其合成代谢基因表达的影响。选择28周龄海兰褐壳蛋鸡96只,随机分为4组,每组24只。对照组饲喂基础饲粮,试验组分别在基础饲粮中添加10%亚麻籽、10%亚麻籽+5%鱼油和5%鱼油。饲养21 d后连续收集7 d鸡蛋,然后每组随机选取4只鸡屠宰取样。结果表明,与对照组相比:1)添加亚麻籽和鱼油均显著增加蛋黄中n-3多不饱和脂肪酸含量(P0.05),其中单独添加鱼油的蛋黄中二十二碳六烯酸(DHA)和二十碳五烯酸含量最高;2)试验组肝脏单不饱和脂肪酸比例均显著降低(P0.05),肝脏n-3多不饱和脂肪酸比例均显著增加(P0.05);3)单独添加鱼油显著降低肝脏脂肪酸延长酶1、脂肪酸延长酶2和去饱和酶(脂肪酸去饱和酶1、脂肪酸去饱和酶2和硬脂酰辅酶A去饱和酶1)基因表达水平(P0.05)。由此可见,蛋鸡饲粮中单独添加亚麻籽或鱼油可以富集蛋黄n-3多不饱和脂肪酸沉积;添加亚麻籽促进肝脏α-亚麻酸转化生成DHA过程,表现为上调脂肪酸延长酶和去饱和酶基因表达,添加鱼油显示相反结果。     

大麦-高粱型饲粮中添加酵母培养物对肥育猪生长性能及肉品质的影响

本试验旨在研究大麦-高粱型饲粮中添加酵母培养物对肥育猪生长性能及肉品质的影响。选择体重相近、日龄基本一致的健康"杜×长×大"杂交肥育猪120头,随机分为3组,每组4个重复,每个重复10头猪。各组分别饲喂玉米-豆粕型饲粮、大麦-高粱型饲粮和在大麦-高粱型饲粮的基础上添加0.8%酵母培养物的试验饲粮。试验期为60 d。结果显示:1)与玉米-豆粕组相比,大麦-高粱组肥育猪平均日增重减少了8.62%(P0.05),料重比增加了9.78%(P0.05),而大麦-高粱+酵母培养物组平均日增重和料重比无显著变化(P0.05)。2)与玉米-豆粕组相比,大麦-高粱组背最长肌亮度(L*)值显著降低(P0.05),红度(a*)值显著升高(P0.05),而大麦-高粱+酵母培养物组L*、a*值无显著差异(P0.05)。各组肥育猪背最长肌p H45m in、滴水损失、肌内脂肪、粗蛋白质和水分等指标均无显著差异(P0.05)。3)与玉米-豆粕组和大麦-高粱组相比,大麦-高粱+酵母培养物组背最长肌饱和脂肪酸含量显著升高(P0.05),而单不饱和脂肪酸(M UFA)含量显著降低(P0.05);皮下脂肪组织中M UFA含量显著降低(P0.05)。4)与玉米-豆粕组相比,大麦-高粱+酵母培养物组挥发性盐基氮的含量显著降低(P0.05)。本研究提示,在大麦-高粱型饲粮中添加0.8%的酵母培养物能有效提高肥育猪的生长性能,改善肉品质。     

Regulation of hepatic peroxisome proliferator‐activated receptor α expression but not adiponectin by dietary protein in finishing pigs

Soy protein regulates adiponectin and peroxisome proliferator‐activated receptor α (PPARα) in some species, but the effect of dietary soy protein on adiponectin and PPARα in the pig has not been studied. Therefore, the objective of this study was to determine whether soya bean meal reduction or replacement influences serum adiponectin, adiponectin mRNA, serum metabolites and the expression of PPARα and other genes involved in lipid deposition. Thirty‐three pigs (11 pigs per treatment) were subjected to one of three dietary treatments: (i) reduced crude protein (CP) diet containing soya bean meal (RCP‐Soy), (ii) high CP diet containing soya bean meal (HCP‐Soy) or (iii) high CP diet with corn gluten meal replacing soya bean meal (HCP‐CGM) for 35 days. Dietary treatment had no effect on overall growth performance, feed intake or measures of body composition. There was no effect of dietary treatment on serum adiponectin or leptin. Dietary treatment did not affect the abundance of the mRNAs for adiponectin, PPARα, PPARγ2, lipoprotein lipase or fatty acid synthase in adipose tissue. The mRNA expression of PPARα, PPARγ2, lipoprotein lipase or fatty acid synthetase in loin muscle was not affected by dietary treatment. In liver tissue, the relative abundance of PPARα mRNA was greater (p < 0.05) in pigs fed the HCP‐Soy diets when compared to pigs fed RCP‐Soy or HCP‐CGM diets. Hepatic mRNA expression of acyl‐CoA oxidase or fatty acid synthase was not affected by dietary treatment. Western blot analysis indicated that hepatic PPARα protein levels were decreased (p < 0.05) in pigs fed the RCP‐Soy diets when compared to pigs fed the HCP‐Soy diets. These data suggest that increasing the soy protein content of swine diets increases hepatic expression of PPARα without associated changes in body composition.     

Activated carbon does not prevent the toxicity of culture material containing fumonisin B1 when fed to weanling piglets

Fumonisins are mycotoxins found primarily in corn and corn products that are produced by Fusarium verticillioides, F. proliferatum, and several other Fusarium species. The toxicity of fumonisin B1 (FB) from culture material with and without activated carbon was evaluated using weanling piglets. Fifty-six weanling pigs were assigned to one of four treatments diets based on BW. The treatment diets were 1) control = corn-soybean basal diet with < 2 ppm FB; 2) AC = control + activated carbon at 1% of the diet, as fed; 3) FB = control + culture material (formulated to contain 30 ppm FB, as-fed basis); and 4) AC + FB = control + activated carbon at 1% of the diet as fed + culture material (formulated to contain 30 ppm FB). A total of four replicates of four pigs per pen for the control and AC treatments and three piglets per pen for the FB and AC + FB treatments were used. Feed and water were offered ad libitum for the duration of the 42-d experiment. Compared with pigs fed the control or AC diets, pigs receiving the two FB-contaminated diets (FB or AC + FB) had lower G:F (P < 0.01), higher serum enzyme activities of gamma-glutamyltransferase and glutamic oxaloacetic transaminase (P < 0.05), and higher concentrations of cholesterol, free sphinganine, sphingosine-1-phosphate, and sphinganine 1-phosphate (P < 0.05). Although animals consuming FB diets showed no signs of respiratory distress, all pigs consuming either the FB or the AC + FB diets had marked pulmonary edema. Lesions were observed in the lungs, heart, and liver of pigs fed the FB or AC + FB diets, and treatment-associated changes also were seen in the pancreas, intestines, spleen, and lymph nodes. No lesions were observed in the brain. In liver, lung, heart, pancreas, spleen, intestines, and lymph nodes, the histopathological effects observed were more severe in the AC + FB group, suggesting that the AC treatment worsened the toxic effects of FB. Additionally, immunological measurements of macrophage function (CD14) were affected (P < 0.05) by the consumption of the FB diets. The consumption of FB diets containing 30 ppm fumonisin B1 from cultured material significantly affected performance, biochemical measurements, and organ pathology in weanling pigs. The addition of activated carbon at the rate of 1% to the diet was not effective in protecting against the detrimental effects of fumonisin consumption.     

Long-Term Feeding of Conjugated Linoleic Acid and Fish Oil to Laying Hens: Effects on Hepatic Histopathology,Egg Quality,and Lipid Components

The present study was conducted to investigate the effect of long-term feeding of conjugated linoleic acid (CLA) and fish oil on egg quality characteristics, production performance, liver pathology, and egg fatty acid content of laying hens. Single Comb White Leghorn laying hens (n = 112), 21 wk old, were placed in cages and randomly assigned to 4 diets (28 hens/diet, 4 replicates of 7 hens) containing 3.0% yellow grease (control), 2.75% yellow grease + 0.25% CLA (YG-CLA), 2.5% yellow grease + 0.25% CLA + 0.25% fish oil (YG-CLA-FO), and 2.75% yellow grease + 0.25% fish oil (YG-FO). The experimental diets were fed for 12 mo. Eggs were collected daily for 12 mo. Feed consumption, hen-day egg production, and feed efficiency were monitored. At the end of the trial, hepatic tissue was collected for histopathology. No effect of diet was found on feed consumption, hen-day egg production, feed efficiency, egg weight, yolk weight, shell weight, or Haugh unit. The YG-CLA and YG-CLA-FO diets produced an increase in CLA and saturated fatty acids in the egg and liver tissue with a concomitant reduction in monounsaturated fatty acids (P < 0.05). Feeding YG-CLA-FO and YG-FO increased the n-3 fatty acids in egg yolk and liver of hens (P < 0.05). No difference was observed in the number of fat vacuoles in the liver tissue. The total fat content of hepatic and abdominal fat pads did not differ among treatments (P > 0.05). Regardless of the diet, as the hens aged, egg weight, yolk weight, and egg total fat increased, and shell weight decreased (P < 0.05). These data demonstrate that eggs with increased n-3 fatty acids and CLA can be generated by minor diet modifications without affecting the production performance or health of birds.     

蛋鸡脂肪肝综合征模型的建立

试验旨在建立蛋鸡脂肪肝综合征病理模型。选取5日龄的海兰褐蛋鸡公雏280只，随机分为对照组（基础日粮组）和3个模型组（A、B、C组），试验第1~10天给模型组饲喂不同配比的高脂饲料，第11~20天饲喂常规基础日粮，每天观察并记录试验鸡精神状态、外观体征、饮水量和食欲情况，试验第0、10、20天从各组随机抽取15只鸡进行翅静脉采血并剖取肝脏和腹脂，测定肝脏系数、肝脂率、腹脂率，血清总胆固醇（TC）、甘油三酯（TG）、谷丙转氨酶（ALT）和谷草转氨酶（AST）水平。结果显示，试验第10天，3个模型组剖检时可见腹腔和肠系膜有大量的脂肪沉积，肝脏系数、肝脂率和腹脂率，以及血清中总胆固醇、甘油三酯、谷丙转氨酶和谷草转氨酶指标均符合鸡脂肪肝综合征模型的诊断标准；试验第20天，模型A、B组谷丙转氨酶和谷草转氨酶水平有所恢复，其他指标仍高于对照组，而模型C组的临床症状和各项检测指标仍符合鸡脂肪肝综合征模型的诊断标准。因此采用连续饲喂高脂饲料C（74.5%基础日粮、6%胆固醇、14%猪油、5%蔗糖、0.5%丙基硫氧嘧啶）可成功建立蛋鸡脂肪肝综合征模型。     

甘氨酸对脂多糖刺激仔猪肝脏能量代谢及相关基因表达的调控作用

本试验旨在研究甘氨酸(Gly)对脂多糖(LPS)刺激断奶仔猪肝脏能量代谢、能量代谢关键酶和相关调节因子mRNA表达的调控作用。选取24头杜×长×大仔猪,分成4个组,每组6个重复。4个组分别为:1)对照组(基础饲粮);2)LPS组(LPS+基础饲粮);3)1.0%Gly组(LPS+基础饲粮+1.0%Gly);4)2.0%Gly组(LPS+基础饲粮+2.0%Gly)。试验第28天,试验组仔猪腹膜注射100μg/kg BW的LPS,对照组注射等量的生理盐水。试验猪于注射LPS或生理盐水4 h后屠宰,取肝脏样品待测。结果表明:1)与LPS组相比,1.0%Gly显著提高了仔猪肝脏三磷酸腺苷(ATP)浓度和能荷(EC)水平(P0.05),显著降低了一磷酸腺苷(AMP)/ATP值(P0.05),并有降低AMP浓度的趋势(P0.10);2.0%Gly有降低AMP/ATP值的趋势(P0.10)。2)与LPS组相比,1.0%Gly显著降低了仔猪肝脏己糖激酶2(Hexok2)和柠檬酸合成酶(CS)的mRNA表达量(P0.05);2.0%Gly显著降低了肝脏Hexok2和丙酮酸激酶(PK)的mRNA表达量(P0.05),并有降低肝脏CS mRNA表达量的趋势(P0.10)。3)与LPS组相比,1.0%Gly显著提高了仔猪肝脏腺甘酸活化蛋白激酶α1(AMPKα1)的mRNA表达量(P0.05)。综上所述,饲粮中添加Gly能够改善LPS刺激引起的断奶仔猪肝脏能量代谢紊乱,调控糖酵解和三羧酸循环等代谢途径中相关酶的表达。     

镰刀菌毒素对断奶仔猪血清酶、肝脏抗氧化功能及组织病理学的影响

试验旨在研究镰刀菌毒素污染日粮对断奶仔猪血清酶、肝脏抗氧化功能及组织病理学的影响。选择35日龄体重为(8.45±0.94) kg的健康三元杂交(杜×长×大)断奶雌性仔猪40头,随机分为2组,每组20个重复,每个重复1头猪。对照组饲喂基础日粮,试验组饲喂用霉变玉米和霉变玉米蛋白粉替代基础日粮中50%的玉米和玉米蛋白粉配制而成的镰刀菌毒素污染日粮(玉米赤霉烯酮(ZEN) 0.90 mg/kg,呕吐毒素(DON) 1.43 mg/kg,烟曲霉毒素(FUM) 5.85 mg/kg)。仔猪单栏饲喂,预试期7 d,正试期35 d。结果表明:①与对照组相比,试验组断奶仔猪血清中谷草转氨酶(AST)、谷丙转氨酶(ALT)和碱性磷酸酶(ALP)活性均显著升高(P<0.05),肝脏相对重显著降低(P<0.05);②与对照组相比,试验组断奶仔猪血清和肝脏中谷胱甘肽过氧化物酶(GSH-Px)和总超氧化物歧化酶(T-SOD)活性均显著降低(P<0.05),而丙二醛(MDA)含量显著升高(P<0.05);③病理组织学观察发现,试验组断奶仔猪肝脏出现一定程度的组织损伤,部分肝小叶边缘发生明显的炎性细胞浸润,肝细胞发生局部空泡变性。由此可知,镰刀菌毒素污染日粮(0.90 mg/kg ZEN,1.43 mg/kg DON,5.85 mg/kg FUM)饲喂断奶仔猪可引起仔猪血清酶活性改变,肝脏抗氧化功能降低,肝脏组织出现一定程度的病理损伤,从而影响肝脏功能的发挥。     

日粮蛋白质水平对乌金猪脂肪代谢相关酶活性的影响

为研究日粮不同蛋白质水平对乌金猪脂肪代谢相关酶活性的影响。选取体重约15 kg的乌金猪54头,随机分为3组,每组3个重复,每个重复6头,在15~30 kg体重阶段饲喂18%(高蛋白质组)、16%(中蛋白质组)和14%(低蛋白质组)蛋白质水平的日粮,30~60 kg体重阶段饲喂16%(高蛋白质组)、14%(中蛋白质组)和12%(低蛋白质组)蛋白质水平的日粮, 60~100 kg体重阶段饲喂14%(高蛋白质组)、12%(中蛋白质组)和10%(低蛋白质组)蛋白质水平日粮,在体重30、60和100 kg体重时分批屠宰,取肝脏及背部皮下脂肪组织测定脂肪酶(LPS)、葡萄糖-6-磷酸脱氢酶(G-6-PDH)和苹果酸脱氢酶(MDH)活性。结果表明,在30 kg体重时,日粮蛋白质水平对乌金猪肝脏和脂肪组织中脂肪代谢相关酶活性差异不显着(P>0.05),在60和100 kg体重时,高蛋白质日粮组乌金猪肝脏和脂肪组织LPS的活性明显高于低蛋白质日粮组(P<0.05),G-6-PDH和MDH活性则明显低于低蛋白质日粮组(P<0.05)。因此,高蛋白质日粮增加了生长中后期乌金猪的内源性能量释放,可能影响了体脂沉积比例。     

长期饲喂不同蛋白质水平饲粮对猪脂肪代谢相关基因表达的影响

本试验旨在研究长期饲喂不同蛋白质水平饲粮对猪脂肪代谢相关基因表达的影响。试验选用18头三元(杜×长×大)杂交28日龄断奶仔猪,随机分为3组,每组6个重复,每个重复1头。对照组[高粗蛋白质(HCP)组]采用符合NRC(2012)推荐营养需要的饲粮,试验组是根据NRC(2012)标准,在添加赖氨酸(Lys)、蛋氨酸(Met)、苏氨酸(Thr)、色氨酸(Try)4种必需氨基酸基础上,将饲粮蛋白质水平分别降低3%[中粗蛋白质(MCP)组]和6%[低粗蛋白质(LCP)组]。试验期125 d。结果表明:1)在肝脏中,与HCP组相比,LCP组显著降低脂肪酸合成相关基因乙酰辅酶A羧化酶(ACC)、脂肪酸合成酶(FAS)、苹果酸酶1(ME1)及锚蛋白1(ANK1)的基因表达量(P0.05);同时显著提高脂肪酸转运相关基因过氧化物酶体增殖物激活受体γ(PPARγ)及脂肪酸结合蛋白(FABP)的基因表达量(P0.05);而MCP组与HCP组相比,脂肪酸合成、转运相关基因表达量均无显著性差异(P0.05);与HCP组相比,MCP及LCP组均显著降低脂肪酸氧化分解相关基因、过氧化物酶体增殖物激活受体α(PPARα)、肉毒碱棕榈酰转移酶(CPT)的基因表达量(P0.05)。2)在背最长肌(LDM)中,MCP组中脂肪酸合成相关基因胆固醇调节元件结合蛋白(SREBP)、FAS、硬脂酰辅酶A去饱和酶(SCD)的基因表达量显著高于其他2组(P0.05);ACC及FABP在LCP组的基因表达量显著低于其他2组(P0.05);CPT基因表达量及LDM的肌内脂肪(IM F)含量在LCP及M CP组显著低于HCP组(P0.05)。3)肝脏和LDM中,各组甘油三酯脂酶(ATG L)及二烯酰辅酶A还原酶(DECR)基因表达量均无显著性差异(P0.05)。由此可见,在NRC(2012)基础上,适当的降低饲粮蛋白质水平(3%)可促进LDM中脂肪酸合成、转运相关基因的表达,但对肝脏中脂肪酸合成相关基因的表达无显著影响;适当的降低饲粮蛋白质水平(3%)可降低LDM及肝脏中脂肪酸氧化分解相关基因的表达,但并不增加LDM肌内脂肪含量。     

骆驼乳清蛋白对热应激所致大鼠肝氧化损伤的保护作用

本试验旨在研究骆驼乳清蛋白（CWP）对热应激（HS）大鼠肝损伤、氧化应激及肝功能的保护作用。选取6周龄SD大鼠36只,适应性饲养2周后随机分为6组：正常对照组饲喂基础日粮;CWP对照组添加400 mg·kg^-1的CWP;HS组除饲喂基础日粮外,每天进行2 h HS处理,连续8 d;3个CWP干预组分别于每次HS前灌服100、200和400 mg·kg^-1的CWP。试验结束后,取大鼠肝组织,HE染色观察肝组织病理学变化,同时检测肝功能生物标志物、氧化应激标志物水平及抗氧化酶活性。结果表明：CWP降低了HS大鼠血清谷草转氨酶（AST）和谷丙转氨酶（ALT）活性,400 mg·kg^-1的CWP干预效果最好（P<0.01）;400 mg·kg^-1CWP干预组有效降低了HS诱导的大鼠肝组织病理学改变; CWP降低了大鼠肝活性氧（ROS）及丙二醛（MDA）水平,增加了超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GSH-Px）活性及谷胱甘肽（GSH）水平,400 mg·kg^-1的CWP干预效果最好（P<0.01）。结果提示,CWP干预能够以剂量依赖性方式降低大鼠肝氧化应激,增加抗氧化系统防御能力,从而缓解HS所致大鼠肝损伤。     

油橄榄叶提取物对酒精性脂肪肝大鼠PP1-DNA-PK-USF1信号通路的干预作用

试验旨在探讨油橄榄叶提取物（olive leaf extract，OLE）防治酒精性脂肪肝（AFLD）的作用机制。将50只健康大鼠随机均分为5组：空白对照组，模型组，OLE高、中、低剂量组，除空白对照组外，其他各组均采用递增法灌胃食用乙醇24周，建立大鼠肝损伤模型，造模同时OLE高、中、低剂量组分别用OLE（1 000、500、250 mg/kg）进行灌胃治疗。利用生物显微技术观察肝脏组织结构的变化，全自动生化分析仪测定血脂水平，实时荧光定量PCR、Western blotting和酶联免疫吸附法（ELISA）检测肝组织蛋白磷酸酶1（PP1）、DNA依赖的蛋白激酶（DNA-PK）、上游刺激因子1（USF1）mRNA水平和蛋白含量。结果显示，与空白对照组相比，模型组大鼠肝脏损伤程度明显加重，血清甘油三酯（TG）、游离脂肪酸（FFA）含量极显著升高（P<0.01）；肝脏PP1、DNA-PK、USF1水平和蛋白含量极显著升高（P<0.01）。与模型组相比，OLE干预后，肝脏病理改变明显减轻；血清TG、FFA含量显著或极显著降低（P<0.05；P<0.01）；肝脏PP1、DNA-PK、USF1 mRNA水平和蛋白含量显著或极显著降低（P<0.05；P<0.01）。结果表明，OLE可通过调节PP1-DNA-PK-USF1信号通路缓解肝脏脂肪变性，抑制AFLD的发展。