血浆极低密度脂蛋白浓度的双向选择对肉鸡腹脂、肝脂和产肉性能的影响

对零世代８周龄血浆极低密度脂蛋白（ＶＬＤＬ）浓度进行降低腹脂的间接选择，一世代取得了明显效果：腹脂和肝脂向两极分化，其中肌胃脂和肝脂选择反应较大。低血浆ＶＬＤＬ的选择使腹脂降低，肝脂增加，对产肉性状未产生不利影响。９周龄腹脂率、板油率和肌胃脂率在高ＶＬＤＬ系分别高于低ＶＬＤＬ系２１％，１６％和５１％；肌胃脂率品系间差异极显著（Ｐ＜０．００１）。品系与性别互作对肌胃脂率有明显影响（Ｐ＜０．０５）。腹脂、肌胃脂存在性别差异，腹脂率雌性略高于雄性，而肌胃脂率雄性高于雌性。９周龄肝脂率，高ＶＬＤＬ系显著低于低ＶＬＤＬ系（Ｐ＜０．０１），雌性高于雄性。一世代８周龄血浆ＶＬＤＬ产生了直接选择反应，血浆ＶＬＤＬ浓度，高ＶＬＤＬ系高于低ＶＬＤＬ系。血浆ＶＬＤＬ存在性别差异，雄性高于雌性。一世代高、低ＶＬＤＬ系血浆ＶＬＤＬ和腹脂的变异系数仍然很大，继续对其选择仍然有效。由于血浆ＶＬＤＬ属中等遗传力，并且家系间差异显著，因此，在世代选育中应采取家系结合个体选择法     

Congenital lipoprotein lipase deficiency in hyperlipemic kitten siblings.

The nature of the hyperlipemia in two 3-week-old male kittens, one of which was presented with the owner's complaints of retarded growth and white streaks on its eyes, was studied. Hypertriglyceridemia, hypercholesterolemia, and reduced Post-Heparin Plasma Lipolytic Activities (PHPLA) were observed in both animals. One of the kittens, however, was more severely affected and in addition, had lipemia retinalis and a marked lactescent, hyperchylomicronemic serum in spite of a short-term fast before sampling. These findings are strikingly similar to those found in human Type I hyperlipoproteinemia due to familial Lipoprotein Lipase (LPL) deficiency. Diagnosis of persistent hyperlipemic syndromes in kittens should include the possibility of LPL deficiency as determined by PHPLA measurements.     

Low-density lipoprotein-related receptor protein 1 (LRP-1) is not required for insulin-like growth factor binding protein 3 (IGFBP-3) to suppress L6 myogenic cell proliferation

Insulin-like growth factor binding protein-3 (IGFBP-3) suppresses proliferation of numerous cell types, including myogenic cells, via both insulin-like growth factor (IGF)-dependent and IGF-independent mechanisms; however, the mechanism of IGF-independent suppression of proliferation is not clearly defined. In nonmuscle cells, binding of IGFBP-3 to the low-density lipoprotein receptor-related protein-1 (LRP-1)/activated α(2)M receptor is reportedly required for IGFBP-3 to inhibit proliferation. These findings suggest that binding to this receptor also may be required for IGFBP-3 to suppress proliferation of cultured myogenic cells. To investigate the role of the LRP-1 receptor in suppression of myogenic cell proliferation by IGFBP-3, we have examined the effect of receptor-associated protein, an LRP-1 receptor antagonist, on recombinant porcine (rp)IGFBP-3 inhibition of L6 myogenic cell proliferation. Treatment with receptor-associated protein results in a 37% decrease (P < 0.05) in the ability of rpIGFBP-3 to inhibit L6-cell proliferation. In L6 cells subjected to LRP-1 small interfering RNA treatment for 48 h (LRP-1 silenced), LRP-1 mRNA levels were reduced by greater than 80% compared with control cultures treated with nonsense small interfering RNA (mock silenced). In addition, the 85-kDa transmembrane subunit of LRP-1 was undetectable in Western immunoblots of total protein lysates from LRP-1-silenced cells. Even though LRP-1 mRNA and protein levels were dramatically reduced in LRP-1-silenced L6 cells compared with mock-silenced controls, rpIGFPB-3 suppressed proliferation rate to the same extent in both LRP-1-silenced and mock-silenced cultures. Our results strongly suggest that, in contrast to data obtained for nonmuscle cell lines, the LRP-1 receptor is not required for IGFBP-3 to suppress proliferation of L6 myogenic cells.     

Daily variations of serum lipids in Ovis aries under different lighting and feeding conditions

The aim of this study was to discriminate the impact of lighting and feeding conditions on the regulation of lipid metabolism in Ovis aries. Six clinically healthy female Comisana ewes, not pregnant and not lactating were kept under different environmental conditions: 12:12 light-dark (LD) cycle, constant darkness and fasting. Blood samples were collected at the end of each period of treatment every 4 h for a 24-h period. Blood concentration of triglycerides, total cholesterol and non-esterified fatty acid showed robust daily rhythmicity in ewes maintained under 12:12 LD cycle and fed ad libitum. Conversely, either constant darkness or fasting had a deep impact on all lipid parameters investigated. Our results suggest that lighting and feeding conditions have an impact on daily variations in lipid metabolism in ewes.     

Effects of dietary lipid levels on lipid deposition and activities of lipid metabolic enzymes in hybrid tilapia (Oreochromis niloticus × O. aureus)

This study was designed to investigate the effects of dietary lipid levels on growth performance, lipid deposition and activities of lipid metabolic enzymes in hybrid tilapia (Oreochromis niloticus × O. aureus). Four isonitrogenous (300 g/kg crude protein) experimental diets containing graded levels of lipid (25, 55, 85 and 115 g/kg) were randomly assigned to triplicate groups of 180 juvenile fish. Fish were fed twice daily for 8 weeks. At the end of the experiment, the growth performance and proximate composition of fish were determined. The activities and gene expression of lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL) were assessed as well. Fish fed the diets with 55 and 85 g/kg lipid had a significantly (p < 0.05) higher body weight gain than those fed the diets with 25 and 115 g/kg lipid. The whole-body and liver lipid contents were significantly (p < 0.05) elevated with increasing dietary lipid levels. Moreover, the activities and mRNA abundances of LPL and HSL in the liver, dorsal muscle and fat tissues were markedly altered by dietary lipid levels. Our data demonstrate a profound influence of dietary lipid levels on the growth and lipid deposition in hybrid tilapia, which is likely associated with the regulation of lipid metabolic enzymes including LPL and HSL.     

洛伐他汀(Lovastatin)对鸡蛋和鸡血浆中胆固醇含量的影响

将44只新扬州鸡随机平均分成4组.对照组用基础日粮,试验组在饲喂基础日粮的同时分别添加0.015%、0.03%和0.06%的洛伐他汀(Lovastatin),研究洛伐他汀对鸡蛋和血浆中胆固醇含量的影响,试验期为5周.试验结果表明:洛伐他汀能显著降低产蛋鸡血浆和鸡蛋中胆固醇水平(P＜0.05),但对产蛋率的影响不显著(P＞0.05).     

摄入不同能量的围产期乳牛肝低密度脂蛋白受体mRNA丰度的比较

将30头健康、经产、处于围产期的黑白花乳牛随机分为3组，每组10头。从产前28d开始，低能量组乳牛饲喂《中国奶牛饲养标准（2000）》减少20％日粮（能量摄入80％），对照组乳牛饲喂《标准》日粮（能量摄入100％），高能量组乳牛饲喂《标准》增加20％日粮（能量摄入120％），产后各组乳牛均饲喂标准日粮。至产后第56d结束试验；采用内对照RT-PCR方法检测摄入不同能量的围产期乳牛肝活体组织低密度脂蛋白受体（LDLR）mRNA丰度。结果，不同能量组乳牛肝LDLR mRNA丰度产前至产后均呈现先升高后降低的趋势。100％和120％能量组肝LDLR mRNA丰度在产后14d达最大值，且产后均高于产前（产后56d除外，P〈0．01或P〈0．05）；而80％能量组产后1d即达到最大值，产前14d至产后14d，LDLR mRNA相对表达量显著高于100％和120％能量组；产后28～56d，120％能量组显著高于80％和100％能量组（P〈0．01）。表明围产期乳牛能量摄入水平对肝LDLR mRNA丰度有显著影响。     

Serum lipid and lipoprotein parameters of Turkman horses

BACKGROUND: Lipid transport systems in animals have been evaluated both as experimental models for lipid and lipoprotein metabolism in humans and to gain insight into the lipid metabolism of specific breeds. The Turkman horse is a pure-blooded horse that lives on the margins of the Caspian Basin; information about serum lipids and lipoproteins in this breed is lacking. OBJECTIVE: The purpose of this study was to evaluate serum lipid and lipoprotein concentrations in clinically healthy Turkman horses. METHODS: Concentrations of triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDLC), low density lipoprotein cholesterol (LDL-C), and very low density lipoprotein cholesterol (VLDL-C), and lipoprotein electrophoretic patterns were determined in serum samples from 48 Turkman horses of both sexes and 0-12 years of age. Results were analyzed by 1-way ANOVA. RESULTS: In both sexes and all age groups, the relative percentages of LDL-C (44.2-64.3%) were higher than those of HDL-C (29.7-47.1%) and VLDL-C (5.9-9.0%). Serum concentrations of TG and TC were significantly higher in male (0.45 +/- 0.12 mmol/L; 2.70 +/- 0.45 mmol/L) than in female (0.34 +/- 0.1 mmol/L; 2.15 +/- 0.3 mmol/L) horses in most age groups. The relative percentages of alpha- and beta-lipoproteins in electrophoretic tracings were 62.77 +/- 5.05% and 36.67 +/- 4.29%, respectively. CONCLUSION: Serum lipid and lipoprotein values in Turkman horses differ from those of other equine breeds, and may be useful for evaluating metabolic diseases in this species.     

家禽脂类代谢调控机理的研究进展

利用营养和分子生物学手段来调控家禽脂类代谢 ,有赖于对其机理的深入了解。本文详细讨论了脂蛋白转运体系在家禽脂类代谢中的作用。通过营养因素和激素水平调控脂蛋白的合成、组装、转运和降解可影响机体脂肪沉积及蛋黄的形成。低密度脂蛋白LDL -受体基因家族在家禽脂蛋白代谢的调控过程中发挥着至关重要的作用     

Serum Profiles of Luteinizing Hormone,Oestradiol and Cholesterol and Ovarian Functions in Layer Poultry Birds (Gallus domesticus) Fed Diets Containing Furazolidone

This study was carried out to assess the serum profiles of luteinizing hormone (LH), oestradiol, cholesterol and ovarian functions in layer poultry birds (Rhode Island Red: Gallus domesticus) fed a diet containing various concentrations of furazolidone (FZ). A total of 40 birds were randomly assigned to receive FZ 0, 200, 400 or 800 mg/kg feed (ppm) daily during the pre-laying age, i.e. 13-18 weeks (for 5 weeks). Blood samples were collected at weekly intervals. Concentrations of LH and oestradiol in serum were estimated at alternate weeks using radioimmunoassays. Serum cholesterol levels were analysed by an enzymatic calorimetric method. Furazolidone administration was terminated at the 18th week of age. The birds were sacrificed at 22nd week of age and ovarian tissues were processed for morphometric studies. Serum LH, oestradiol and cholesterol levels were affected by age (p < 0.001) and FZ dose (p < 0.001). Serum LH and oestradiol levels were lower (p < 0.05) in birds receiving FZ 800 mg/kg feed daily compared with the controls, whereas serum cholesterol profiles were lower (p < 0.05) in all FZ-administered groups than in the control group. The mean weight of ovaries having no yolky follicles observed in the group receiving FZ 400 or 800 mg/kg feed per day was reduced (p < 0.05) compared with the control group. Dosing FZ at 800 mg/kg feed per day reduced (p < 0.05) the mean volume of ovaries having no yolky follicles compared with the control group. In birds receiving FZ 800 mg/kg feed per day, the mean length of the oviduct was reduced (p < 0.05) as compared with the control group. Morphometric studies revealed that the mean number of oocytes with diameter in the range 401-800 microm decreased (p < 0.05) in birds fed FZ 400 or 800 mg/kg feed per day. Initial egg production was affected by age (p < 0.001) and dose (p < 0.001) of FZ. The mean number of eggs laid by different groups revealed that egg production was reduced (p < 0.05) in birds receiving FZ 800 mg/kg feed per day as compared with the controls. The present data suggest that FZ causes suppression in serum profiles of LH, oestradiol, cholesterol and ovarian functions in Rhode Island Red layer poultry birds. Therefore, great care must be taken with use of FZ in layer poultry birds (Gallius domesticus) with regard to dosage and duration of administration.