• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1378-1382
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• 2004

Zinc (Zn) is a micromineral and functions as a cofactor of many enzymes and its deficiency induces retardation of growth and dysfunction of the immune system in animals. This study was conducted to determine lipogenic activity of Zn in bovine intramuscular adipocytes. Preadipocytes were isolated from intramuscular fat depots of 26 month old Korean (Hanwoo) steers and cultured in media containing Zn. At confluence, the cells were treated with insulin, dexamethasone, and 1-methyl-3-isobutyl-xanthine to induce differentiation (accumulation of lipid droplets in cells). The sources of Zn were zinc chloride (${ZnCl}_2$) and zinc sulfate (${ZnSO}_4$), and the final concentrations of both Zn sources were 0, 5, 25, 50 and 100 ${\mu}$M. Glycerol-3-phosphate dehydrogenase (GPDH) activity, an index of adipocyte differentiation, was increased as the concentration of Zn in media increased showing the highest activity (25.74 ng/min/mg protein) at 25 ${\mu}$M of ${ZnSO}_4$. Supplementation of Zn during differentiation of bovine intramuscular adipocytes tended to decrease the production of nitric oxide (NO). Peroxisome proliferator-activated receptor gamma 2(PPAR$\gamma$2) gene expression was increased 10 days after differentiation induction. The current results indicate that Zn has a strong lipogenic activity in cultured bovine intramuscular adipocytes with remarkable suppression of NO production.

• Journal of Nutrition and Health
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• v.17 no.4
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• pp.290-296
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• 1984

In order to evaluate the effect of fish oil on lipogenesis, activities of glucose-6-phosphate dehydrogenase ( G6PDH ) and malic enzyme (ME) were measured in liver of rats fed mackered oil(MO) or eel oil (EO) for 10 to 14 days, at the various levels of 0 to 10% (w/w ). In addition to two kinds of fish oil, soybean oil (SO), lard (L), and beef tallow (BT) were fed to the different groups of rats. When fish oil was below 10%(w/w ), soybean oil, lard, or beef tallow was mixed with fish oil to maintain constant 10% (w/w) fat level. Three days of feeding MO brought a marked decrease$({\sim}{50}%)$ both in G6PDH and ME activity, the former of which maintained during 13 days of feeding. L group had highest levels of both enzymes. G6PDH activity of MO was lower than SO, but ME activity was not different between MO and SO. G6PDH activity was decreased with increasing content of fish oil (MO, EO), starting at the 2%(w/w) level of fish oil, when L or BT was used as filler oil. But ME activity was significantly reduced when fish oil content was at least 5%(w/w). Difference between the effects shown by two kinds of fish oil and animal species were also found. The present study suggests that fish oil can suppress hepatic lipogenesis by reducing activities of lipogenic enzymes with the same or higher degree than vegetable oil can exert.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.195-207
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• 2021

Species A rotaviruses (RVAs) replicate and assemble their immature particles within electron dense compartments known as viroplasms, where lipid droplets (LDs) interact with the viroplasm and facilitate viral replication. Despite the importance of LD formation in the life cycle of RVAs, the upstream molecules modulating LD formation remain unclear. This study aimed to find out the role of sterol regulatory element-binding proteins (SREBPs) in reprogramming of LD formation after RVA infection. Here, we demonstrate that RVA infection reprograms the sterol regulatory element-binding proteins (SREBPs)-dependent lipogenic pathways in virus-infected cells, and that both SREBP-1 and -2 transactivated genes, which are involved in fatty acid and cholesterol biosynthesis, are essential for LD formation. Our results showed that pharmacological inhibition of SREBPs using AM580 and betulin and inhibition of their downstream cholesterol biosynthesis (simvastatin for HMG-CoA reductase) and fatty acid enzymes (TOFA) negatively modulated the intracellular triacylglycerides and cholesterol levels and their resulting LD and viroplasm formations. Interestingly, pharmacological inhibition of SREBPs significantly reduced RVA protein synthesis, genome replication and progeny production. This study identified SREBPs-mediated lipogenic reprogramming in RVA-infected host cells, which facilitates virus replication through LD formation and its interaction with viroplasms, suggesting that SREBPs can be a potential target for the development of efficient and affordable therapeutics against RVA infection.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.11
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• pp.1562-1569
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• 2004

The objective of this experiment was to determine the effects of n-3 polyunsaturated fatty acids (n-3 PUFAs)-enriched diet supplemented with different levels of $\alpha$-tocopherol on the activities of hepatic lipogenic-related enzymes and the contents of liver and plasma lipid fractions in laying Tsaiya ducks. A total of 180 30-wk-old laying Tsaiya ducks, at the beginning of peak production, were allotted into 6 treatments with 3 replicates each. Ducks were fed one of the 6 experimental diets, containing 4% tallow (control), and 4% fish oil supplemented with graded levels of $\alpha$-tocopheryl acetate ($\alpha$-tocopherol) at 0, 100, 200, 300 and 400 mg/kg, respectively, for 6 wks. Feed and water were supplied ad libitum throughout the experimental period. The results indicated that the n-3 PUFAsenriched diet supplemented with different levels of $\alpha$-tocopherol did not affect (p>0.05) egg weight, feed intake, body weight change or liver and abdominal fat weights. Egg production, egg mass and feed efficiency significantly (p<0.05) improved as dietary $\alpha$-tocopherol levels increased. The activities of hepatic lipogenic-related enzymes including acetyl-CoA carboxylase (EC 6. 2. 1. 3; ACC), glucose-6-phosphate dehydrogenase (EC 1. 1. 1. 49; G-6-PDH), ATP-citrate cleavage enzyme (EC 4. 1. 3. 8; CCE), NADP-malate dehydrogenase (EC 1.1.1.40; NADP-MDH) and fatty acid synthetase (FAS) were higher (p<0.05) in birds fed with the tallow diet than in those fed with fish oil diets and increased with increasing dietary $\alpha$-tocopherol levels. None of the dietary treatments significantly affected the contents of triglyceride and total cholesterol in the liver, or total cholesterol, phospholipid and total lipid in the plasma. However, the contents of phospholipid and total lipid in the liver, and triglyceride in the plasma increased as dietary $\alpha$-tocopherol levels increased. Increasing dietary $\alpha$-tocopherol levels decreased the non-esterified fatty acid (NEFA) content in the plasma and trended to decrease the cholesterol contents in the egg yolk. The lipid metabolism of laying Tsaiya ducks was influenced not only by the dietary fat but also by the supplementation levels of $\alpha$-tocopherol.

• Applied Biological Chemistry
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• v.22 no.3
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• pp.173-180
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• 1979

SDS gel electrophoresis has been employed to examine the changes in distribution of three major classes of nuclear proteins extracted from isolated liver nuclei in response to refeeding of starved rats with a fat-free high carbohydrate diet and following insulin injection into streptozotocin-diabetic rats. The relative quantity of electrophoretically separated proteins in the fraction showed marked changes with 0.14 NaCl extracts, but not with histones and phenol soluble non-histone proteins. During 48h starvation at least five proteins ranging in molecular weight from 50,000 to 180,000 daltons decreased relative to normal controls while a protein with 36,000 daltons was increased. Refeeding the starved rats with a high carbohydrate diet reversed these changes over 24 h. Insulin injection into streptozotocin-diabetic rats increased levels of the set of five 0.14 M NaCl soluble proteins identified from refeeding experiment of starved rats. The 36,000 daltons protein was also diminished. These results indicate that changes in distribution of certain nuclear proteins in 0.14M NaCl extracts are associated with the control of nuclear activity ralated to known insulin-signalled modulation and induction of cytosolic lipogenic enzymes.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.10
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• pp.1524-1528
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• 2003

The present study was conducted to evaluate the influence of dietary fiber on the activities of malic enzyme and citrate lyase involved in fatty acid metabolism in the colon epithelium of pigs. Thirty-six weaned 5 weeks old crossbred (Yorkshire${\times}$Swedish Landrace) piglets originating from twelve litters were randomly assigned to either a low fiber diet containing 10% non-starch polysaccharides (NSP), a control diet containing 14.7% NSP or a high fiber diet containing 20% NSP. The activity of malic enzyme in the colonic epithelium of pigs significantly (p<0.05) increased with age during the suckling-weaning transition. There was a tendency (p<0.10) of decreased malic enzyme activity in the colonic epithelium of pigs fed on the high fiber diet. At week 6, a lowered (p<0.01) activity of malic enzyme in pigs fed on the low fiber diet compared with that in pigs fed on the high fiber and the control diets. Nevertheless, there were no significant differences in the activity of citrate lyase observed either between pigs with different ages or between pigs fed with various diets. The current data suggest that piglets during the suckling-weaning transition have a limited capacity to synthesize fatty acids from carbohydrate derivatives in the coloncytes. In addition, lipogenesis in coloncytes was enhanced with age during the suckling-weaning transition. A tendency (p<0.10) to an increased capacity to utilize acetyl-CoA in coloncytes of pigs has been observed for the high fiber diet. Moreover, the present work indicated that dietary fiber resulted in a lowered rate of lipogenesis and a reduced activity of malic enzyme.

• BMB Reports
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• v.40 no.4
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• pp.525-531
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• 2007

As a $\beta_2$-adrenergic agonist, clenbuterol decreases body fat, but the molecular mechanism underlying this process is unclear. In the present study, we treated 293T and L-02 cells with clenbuterol and found that clenbuterol downregulates SREBP-1c expression and upregulates CREB1 expression. Considering SREBP-1c has the function of regulating the transcription of several lipogenic enzymes, we considered that the downregulation of SREBP-1c is responsible for body fat reduction by clenbuterol. Many previous studies have found that clenbuterol markedly increases intracellular cAMP levels, therefore, we also investigated whether CREB1 is involved in this process. The data from our experiments indicate that CREB1 overexpression inhibits SREBP-1c transcription, and that this action is antagonized by CREB2, a competitive inhibitor of CREB1. Furthermore, since PPARs are able to repress SREBP-1c transcription, we investigated whether clenbuterol and CREB1 function via a pathway involving PPAR activation. However, our results showed that clenbuterol or CREB1 overexpression suppressed PPARs transcription in 293T and L-02 cells, which suggested that they impair SREBP-1c expression in other ways.

• Preventive Nutrition and Food Science
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• v.17 no.3
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• pp.223-227
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• 2012

This study examined the effects of corn gluten (CG), wheat gluten (WG), and soybean protein isolate (SPI), as well as their hydrolysates, on weight reduction in rats fed a high-fat diet. Eight-month-old male Sprague-Dawley rats (n=70) were fed a high-fat diet (40% of the calories were fat) for 4 weeks. Rats were then randomly divided into seven groups and were fed isocaloric diets with different protein sources for 8 weeks. The protein sources were casein (control group), intact CG (CG group), CG hydrolysate (CGH group), intact WG (WG group), WG hydrolysate (WGH group), intact SPI (SPI group), and SPI hydrolysate (SPIH group). Body weight gain, adipose tissue weights, lipid profiles in plasma and liver; and hepatic activities of carnitine palmitoyl transferase, fatty acid synthase (FAS), malic enzyme, and glucose-6-phosphate dehydrogenase were assessed. The CGH group showed significant weight reduction compared with the other groups. Epididymal fat pad and plasma triglycerides in the CGH group were the lowest and were significantly different than those in the control group. FAS activity in the CGH group was significantly lower than that in the other groups. In conclusion, the CGH diet of these experimental animals demonstrated a weight-reducing effect by lowering the adipose tissue weight and by affecting the activities of hepatic lipogenic enzymes.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.7
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• pp.1026-1030
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• 2002

A trial was conducted to investigate the effect of dietary NMA on several growth associated hormones and fat metabolism in finishing pigs. A total of 84 crossbred finishing pigs (average initial BW of $56{\pm}$0.37kg) were divided into 6 pens, 14 pigs per pen (7 gilts and 7 barrows per pen). 3 pens of pigs were fed with control diet (corn-soybean meal) and the others were fed control diet addition with 50 mg/kg NMA. During the trial, all pigs were given free access to feed and water. After 44 days trial, 8 pigs from each treatment (4 gilts and 4 barrows, weight similar to average group weight, $86.94{\pm}0.71kg$ for control group, and $90.55{\pm}1.51kg$ for NMA treated group) were sacrificed to collect the sample of the liver, longissimus muscle, subcutaneous fat (10th rib). The addition of NMA in diet increased the IGF-I, Insulin, T3, T4 levels in serum by 50.68% (p<0.05), 38.36% (p<0.05), 123.33% (p<0.01), 60.58% (p<0.03), respectively. Meanwhile, IGF-I level in the liver and the muscle were increased with 17.83% (p<0.03) and 26.00% (p<0.03) with addition of NMA. The data from subcutaneous fat (10th rib) analysis showed that supplement of 50 mg/kg NMA decreased the total activities of malic dehydrogenase (MDH) by 20.54% (p<0.05), glucose-6- phosphate dehydrogenase (G-6-DPH) by 16.97% (p<0.05), and decreased the specific activities of MDH and G-6-DPH by 37.46% (p<0.01) and 35.06% (p<0.01), respectively. The hormone sensitive lipase (HSL) total activity was increased by 25.00% (p<0.05) in NMA treated pigs. These results indicated that addition of 50 mg/kg NMA to diet can induce the endocrine great change in finishing pigs, furthermore, inhibit the fat synthesis through suppressing lipogenic enzymes and promote the fat degradation by elevating HSL activity in finishing pigs.

• Journal of Nutrition and Health
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• v.28 no.4
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• pp.268-281
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• 1995

This study was undertaken to elucidate the effect of DHA-rich fish oil (DHA-rich oil) added to different dietary fats on lipid metabolism. Rats were fed perilla oil, sesame oil and beef tallow with or without DHA-rich oil for 12 weeks. The weight gain was higher in groups with DHA-rich oil than that of groups without DHA-rich oil, with DHA-rich oil, while weight of epididymal fat pad was lower in perilla oil and beef tallow groups with DHA-rich oil. The contents of total lipid and triglyceride in plasma were not affected by dietary fat types, but that of total and HDL cholesterol in plasma were higher in sesame oil group than perilla oil and beef tallow groups without DHA-rich oil. The contents of total lipid, triglyceride, total cholesterol, HDL cholestrol and LDL cholesterol in plasma were decreased by DHL-rich oil addition. The contents of total lipid, total cholesterol and triglyceride in the liver were not affected by dietary fat type. The contents of total cholesterol and triglyceride in the liver were not affected by dietary fat type. The contents of total lipid and TG in liver were not affected by DHA-rich oil addition while hepatic cholesterol increased by DHA-rich oil addition. The activities of glucose 6-phosphate dehydrogenase and malic enzyme were highest in beef tallow group without DHA-rich oil and decreased by DHA-rich oil addition. Peroxisomal ${\beta}$-oxidation had an inverse relationship against the activities of lipogenic enzymes. In conclusion, dietary DHA-rich oil decreased fat accumulation and had hypolipidemic effect, especially in beef tallow group. Also groups with DHA-rich oil showed more hypolipidemic effect than perilla oil group. And DHA-rich oil addition to diets resulted in increasing dietary n-3/n-6 ratio. Therefore increase in n-3/n-6 ratio as well as dietary DHA were considered to be responsible for the hypolipidemic effect resulted from DHA-rich oil addition.