Plant oils' inclusion in high fish meal‐substituted diets: effect on digestion and nutrient absorption in gilthead sea bream (Sparus aurata L.)

Here, we performed an 11‐week trial to study the effects of four experimental diets on the digestion, nutrient absorption and intestinal histology of gilthead sea bream. The diets were formulated with a low fish meal content (25%) and were rich (75%) in plant proteins. Fish oil (FO) was replaced at 0%, 33%, 66% and 100% by graded levels of a blend of vegetable oils (VO) (diets FO, 33VO, 66VO and 100VO respectively). Protease activity increased in the pyloric caeca (PC) and decreased in the proximal intestine (PI) of the 66 and 100VO groups, while lipase and α‐amylase activities were not modified by VO. The capacity of brush‐border membrane vesicles obtained from PC, PI and distal intestine to absorb amino acids was not modified, but d ‐glucose and linoleic acid absorption diminished when VO was included in the diets. In summary, these results show that when 75% of protein is provided by vegetable sources in the diet of gilthead sea bream, up to 66% of FO can be replaced by a blend of VO without compromising digestive processes. Only the total replacement of VO results in an impaired digestion, with reduced total protease activity and accumulation of lipid droplets in the enterocytes of the PI.     

沙葱和油料籽实对绵羊血液、肝脏和胰脏脂酶活性的影响

旨在研究沙葱和油籽对绵羊血液、肝脏和胰脏脂酶活性的影响,为沙葱和油籽用于羊肉品质的改善提供科学依据.试验选用28只蒙古羯羊,采用完全区组试验设计,研究精料中添加4%沙葱、3种籽实组合(8%胡麻+2%葵花籽+2%线麻籽)及4%沙葱+3种油料籽实组合(4%沙葱+8%胡麻+2%葵花籽+2%线麻籽)对绵羊血液、肝脏和胰脏脂酶活性的影响.结果表明,3个添加组均显著提高血清总脂酶活力(P<0.05);沙葱+油料籽实组和油料籽实组显著提高血清HL的活力(P<0.05);沙葱+油料籽实组显著提高血清LPL的活力(P<0.05);3个添加组对肝脏中3个酶的活性均无显著影响(P>0.05),均显著提高胰脂肪酶活性(P<0.05),其中各项指标均以沙葱+油料籽实组为最好.     

Changes in activities and mRNA expression of lipoprotein lipase and fatty acid synthetase in large yellow croaker,Larimichthys crocea (Richardson), during fasting

Over‐winter fasting and man‐made food deprivation to increase meat quality are common in the process of large yellow croaker (Larimichthys crocea) aquaculture. This study aimed to determine the changes in lipoprotein lipase (LPL) and fatty acid synthetase (FAS) activities and mRNA expressions, and the relationships between these changes and fat content in large yellow croaker liver and muscle tissues during fasting. A total of 2933 bp LPL cDNA, including an open reading frame of 1533 bp encoding 510 amino acids, and a 1233 bp fragment of FAS cDNA coding 411 amino acids were cloned. Expressions of both genes were ubiquitous. During a 35‐day fasting period, the hepatosomatic index and fat content in muscle and liver were significantly decreased (P < 0.05). mRNA levels of LPL increased significantly during the fasting period except the first 3 days, and FAS mRNA levels decreased significantly in both muscle and liver (P < 0.05) although there were some fluctuations. Muscle and liver LPL activities were significantly higher following fasting for 7 days, decreased to the initial value following fasting for 14 days, and elevating significantly afterwards (P < 0.05). FAS activities in muscle and liver maintained a significantly decreasing trend during the short‐term fasting (P < 0.05) and kept obviously rising thereafter (P < 0.05). Activities and mRNA levels of both LPL and FAS were not always consistent, which implied that both pre‐translational and post‐translational regulations existed during fasting. Our results suggest that the reasonable fasting time is 21 days before harvesting when fat content decreased significantly.     

米糠稳定化研究进展

稳定化处理是米糠能够有效利用的先决条件。本文介绍米糠稳定化处理的意义、方法及其进展。对米糠稳定化处理的要求、食品用稳定化米糠的质量标准、各种稳定化方法的优缺点及其发展现状作了相应的介绍。     

无溶剂体系脂肪酶催化合成阿魏酸双油酸甘油酯

对无溶剂体系中脂肪酶催化合成新型油脂抗氧化剂阿魏酸双油酸甘油酯进行了研究。以Novozym 435脂肪酶为催化剂,以阿魏酸乙酯和三油酸甘油酯为底物,合成阿魏酸双油酸甘油酯。探讨了减压旋转蒸发、底物比、温度、反应时间、酶的稳定性等因素对产率的影响。结果表明,无溶剂体系中,在110mg Novozym 435催化下,水活度小于0.01,转速为180r/min,底物比(阿魏酸乙酯∶三油酸甘油酯)为1∶2,温度为50℃,真空度为0.001MPa,旋转蒸发反应120h时的产率最高。固定化酶可反复使用多次,活性没有明显损失。     

二氢吡啶对产蛋鸡的作用效果及机理研究

１０２４羽罗曼蛋鸡随机分４组,分别饲喂二氢吡啶添加量为０,１００,１５０,２００ｍｇ／ｋｇ的４种饲粮,结果表明：二氢吡啶可以显著地改进蛋鸡的产蛋性能,其中添加１５０ｍｇ／ｋｇ效果最佳,产蛋率提高了１１．０８％,料蛋比降低了１０．３６％．蛋重随日粮中二氢吡啶递增呈上升趋势．二氢吡啶使血清尿酸含量显著降低（ｐ＜０．０５）;二氢吡啶使血清Ｃａ浓度、Ｐ浓度下降（ｐ＜０．０５）,具有降低破蛋和异常蛋的作用（ｐ＜０．０５）;二氢吡啶可促进浓蛋白和蛋黄的合成（ｐ＜０．０５）,降低蛋黄中胆固醇的含量;添加二氢吡啶还显著地提高了脂肪酶活性（ｐ＜０．０５）,降低了血清甘油三酯和总胆固醇含量（ｐ＜０．０１）,降低腹脂率和肝脏中脂肪含量（ｐ＜０．０１）,防止脂肪肝的发生;二氢吡啶还可以提高血清超氧化物岐化酶活力（ｐ＜０．０１）,对血清ＧＰＴ与ＧＯＴ无明显影响,因而具有保护生物膜的作用．     

Acylated Aminooligosaccharides from the Yellow Sea Streptomyces sp. HO1518 as Both α-Glucosidase and Lipase Inhibitors

Three new acylated aminooligosaccharide (1–3), along with five known congeners (4–8), were isolated from the marine-derived Streptomyces sp. HO1518. Their structures were fully elucidated by extensive spectroscopic analysis, mainly based on 1D-selective and 2D TOCSY, HSQC-TOCSY, and HRESIMS spectrometry measurements, and by chemical transformations. All of the compounds were evaluated for their α-glucosidase and pancreatic lipase inhibitory activities. Among the isolates, D6-O-isobutyryl-acarviostatin II03 (3) and D6-O-acetyl-acarviostatin II03 (8), sharing acarviostatin II03-type structure, showed the most potent α-glucosidase and lipase inhibitory effects, far stronger than the antidiabetic acarbose towards α-glucosidase and almost equal to the anti-obesity orlistat towards lipase in vitro. This is the first report on inhibitory activities against the two major digestive enzymes for acylated aminooligosaccharides. The results from our investigation highlight the potential of acylated aminooligosaccharides for the future development of multi-target anti-diabetic drug.     

Dopamine in substantia nigra is involved in the regulation of synthesis and lipolysis of retroperitoneal white adipose tissue in rats

AIM: To observe the alterations of fatty acid synthase (FAS), hormone-sensitive lipase (HSL) and phosphorylated HSL (p-HSL) in retroperitoneal white adipose tissue (rWAT) in a 6-hydroxydopamine (6-OHDA)-induced Parkinson disease (PD) rat model. METHODS: SD rats (n=20) were randomly divided into PD model group and control group. 6-OHDA was injected into bilateral substantia nigra (SN) of the rats in PD model group, and the same volume of saline was injected into the same position of the rats in control group. Food intake was measured daily. Six weeks after operation, rotarod test was performed, and the body weight and rWAT weight of the rats were recorded. Immunohistochemistry was used to observed the change of tyrosine hydroxylase (TH) in SN. HE staining was used to observe the morphological change of adipocytes in rWAT, and the diameter of adipocytes was measured by ImageJ software. The protein levels of TH in SN, and FAS, p-HSL and HSL in rWAT were determined by Western blot. RESULTS: Compared with control group, TH-positive neurons in SN were significantly reduced, and the motor ability of PD model rats was significantly decreased. No obvious change of daily food intake and body weight was observed, but the ratio of rWAT weight/body weight and the diameter of adipocytes in rWAT of PD model rats were significantly decreased. The protein level of FAS was decreased significantly. The protein level of p-HSL was increased significantly, while the protein level of HSL did not change. CONCLUSION: Dopamine in SN is involved in the regulation of rWAT synthesis and lipolysis in rats. The metabolic changes of rWAT caused by the destroy of SN may be related to the weight loss of PD patients.     

产脂肪酶菌株的筛选及酶学特性研究

从富油土壤中分离筛选到58株脂肪酶产生菌,其中GXL 02菌株产脂肪酶的能力较强,根据其形态特征及16S rDNA序列分析,初步鉴定为不动杆菌。GXL 02发酵产酶需油脂的诱导,同时也依赖M g2 ,培养基中不添加M g2 时几乎不产酶,微量的M g2 就能激活菌体产酶。葡萄糖、蔗糖等糖类物质不利于GXL 02产脂肪酶。该酶的最适作用温度为5 0°C,最适作用pH为9.0,6 0°C保温9 0 m in酶活基本不损失,在pH 3.0~10.0范围内稳定。     

Butenolides from the Coral-Derived Fungus Aspergillius terreus SCSIO41404

Five undescribed butenolides including two pairs of enantiomers, (+)-asperteretal G (1a), (−)-asperteretal G (1b), (+)-asperteretal H (2a), (−)-asperteretal H (2b), asperteretal I (3), and para-hydroxybenzaldehyde derivative, (S)-3-(2,3-dihydroxy-3-methylbutyl)-4-hydroxybenzaldehyde (14), were isolated together with ten previously reported butenolides 4–13, from the coral-derived fungus Aspergillus terreus SCSIO41404. Enantiomers 1a/1b and 2a/2b were successfully purified by high performance liquid chromatography (HPLC) using a chiral column, and the enantiomers 1a and 1b were new natural products. Structures of the unreported compounds, including the absolute configurations, were elucidated by NMR and MS data, optical rotation, experimental and calculated electronic circular dichroism, induced circular dichroism, and X-ray crystal data. The isolated butenolides were evaluated for antibacterial, cytotoxic, and enzyme inhibitory activities. Compounds 7 and 12 displayed weak antibacterial activity, against Enterococcus faecalis (IC₅₀ = 25 μg/mL) and Klebsiella pneumoniae (IC₅₀ = 50 μg/mL), respectively, whereas 6 showed weak inhibitory effect on acetylcholinesterase. Nevertheless, most of the butenolides showed inhibition against pancreatic lipase (PL) with an inhibition rate of 21.2–73.0% at a concentration of 50 μg/mL.