• Journal of Animal Science and Technology
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• 제55권4호
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• pp.303-314
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• 2013

Knowledge regarding lipid catabolism has been of great interest in the field of animal sciences. In the livestock industry, excess fat accretion in meat is costly to the producer and undesirable to the consumer. However, intramuscular fat (marbling) is desirable to enhance carcass and product quality. The manipulation of lipid content to meet the goals of animal production requires an understanding of the detailed mechanisms of lipid catabolism to help meticulously design nutritional, pharmacological, and physiological approaches to regulate fat accretion. The concept of a basic system of lipases and their co-regulators has been identified. The major lipases cleave triacylglycerol (TAG) stored in lipid droplets in a sequential manner. In adipose tissue, adipose triglyceride lipase (ATGL) performs the first and rate-limiting step of TAG breakdown through hydrolysis at the sn-1 position of TAG to release a non-esterified fatty acid (NEFA) and diacylglycerol (DAG). Subsequently, cleavage of DAG occurs via the rate-limiting enzyme hormone-sensitive lipase (HSL) for DAG catabolism, which is followed by monoglyceride lipase (MGL) for monoacylglycerol (MAG) hydrolysis. Recent identification of the co-activator (Comparative Gene Identification-58) and inhibitor [G(0)/G(1) Switch Gene 2] of ATGL have helped elucidate this important initial step of TAG breakdown, while also generating more questions. Additionally, the roles of these lipolysis-related enzymes in muscle, liver and skin tissue have also been found to be of great importance for the investigation of systemic lipolytic regulation.

• Molecules and Cells
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• 제45권9호
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• pp.649-659
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• 2022

A long-term energy nutritional imbalance fundamentally causes the development of obesity and associated fat accumulation. Lysosomes, as nutrient-sensing and lipophagy centers, critically control cellular lipid catabolism in response to nutrient deprivation. However, whether lysosome activity is directly involved in nutrient-induced fat accumulation remains unclear. In this study, worm fat accumulation was induced by 1 mM glucose or 0.02 mM palmitic acid supplementation. Along with the elevation of fat accumulation, lysosomal number and acidification were also increased, suggesting that lysosome activity might be correlated with nutrient-induced fat deposition in Caenorhabditis elegans. Furthermore, treatments with the lysosomal inhibitors chloroquine and leupeptin significantly reduced basal and nutrient-induced fat accumulation in C. elegans. The knockdown of hlh-30, which is a critical gene in lysosomal biogenesis, also resulted in worm fat loss. Finally, the mutation of aak-2, daf-15, and rsks-1 showed that mTORC1 (mechanistic target of rapamycin complex-1) signaling mediated the effects of lysosomes on basal and nutrient-induced fat accumulation in C. elegans. Overall, this study reveals the previously undescribed role of lysosomes in overnutrition sensing, suggesting a new strategy for controlling body fat accumulation.

• 한국응용과학기술학회지
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• 제36권3호
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• pp.797-803
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• 2019

Recently, osteosarcopenic obesity (OSO) has been identified and notified world wide. Therefore, this study reviewed OSO related to lifestyle factors such as nutritional intake and exercise. Due to aging, OSO may be initiated by dietary factors and obesity related factors. Reduced muscle mass and increased fat mass may negatively impact bone health causing OSO. The complication of OSO development should be related to dietary imbalance combined with declined exercise and this may contribute to induce OSO by decreasing bone mass, muscle mass, and increasing obesity with aging. To prevent OSO, reaching peak bone mass and building optimal muscle and fat mass through exercise would be recommended. For treating OSO, balanced dietary intake and regular exercise through a whole life would be needed. In addition, sufficient carbohydrate and fat intake for minimizing protein catabolism would be recommended to prevent OSO. The combination of aerobic exercise and resistance training also would be an effective intervention for OSO population.

• Journal of Animal Science and Technology
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• 제62권5호
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• pp.595-604
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• 2020

This study investigated the effects of dietary rumen-protected L-tryptophan (TRP) supplementation (43.4 mg of L-tryptophan kg^-1 body weigt [BW]) for 65 days in Hanwoo steers on muscle development related to gene expressions and adipose tissue catabolism and fatty acid transportation in longissimus dorsi muscles. Eight Hanwoo steers (initial BW = 424.6 kg [SD 42.3]; 477 days old [SD 4.8]) were randomly allocated to two groups (n = 4) of control and treatment and were supplied with total mixed ration (TMR). The treatment group was fed with 15 g of rumen-protected TRP (0.1% of TMR as-fed basis equal to 43.4 mg of TRP kg^-1 BW) once a day at 0800 h as top-dressed to TMR. Blood samples were collected 3 times, at 0, 5, and 10 weeks of the experiment, for assessment of hematological and biochemical parameters. For gene study, the longissimus dorsi muscle samples (12 to 13 ribs, approximately 2 g) were collected from each individual by biopsy at end of the study (10 weeks). Growth performance parameters including final BW, average daily gain, and gain to feed ratio, were not different (p > 0.05) between the two groups. Hematological parameters including granulocyte, lymphocyte, monocyte, platelet, red blood cell, hematocrit, and white blood cell showed no difference (p > 0.05) between the two groups except for hemoglobin (p = 0.025), which was higher in the treatment than in the control group. Serum biochemical parameters including total protein, albumin, globulin, blood urea nitrogen, creatinine phosphokinase, glucose, nonesterified fatty acids, and triglyceride also showed no differences between the two groups (p > 0.05). Gene expression related to muscle development (Myogenic factor 6 [MYF6], myogenine [MyoG]), adipose tissue catabolism (lipoprotein lipase [LPL]), and fatty acid transformation indicator (fatty acid binding protein 4 [FABP4]) were increased in the treatment group compared to the control group (p < 0.05). Collectively, supplementation of TRP (65 days in this study) promotes muscle development and increases the ability of the animals to catabolize and transport fat in muscles due to an increase in expressions of MYF6, MyoG, FABP4, and LPL gene.

• Nutrition Research and Practice
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• 제3권3호
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• pp.200-207
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• 2009

This study examined the effects of com gluten (CG) and its hydrolysate consumptions on weight reduction in rats fed a high-fat diet. Eight-month-old male Sprague-Dawley rats (n=40) were fed a high-fat diet (40% calorie as fat) for 4 weeks. They were then randomly divided into four groups and fed the isocaloric diets with different protein sources for 8 weeks. The protein sources were casein (control group), intact CG (CG group), CG hydrolysate A (CGHA group, 30% of protein as peptides and 70% as free amino acids) and CG hydrolysate P (CGHP group, 93% of protein as peptides and 7% as free amino acids). Body weight gain, adipose tissue weights, nitrogen balance, absorptions of energy, protein and fat, lipid profiles in plasma, liver and feces and hepatic activities of camitine palmitoyl transferase (CPT), fatty acid synthase (FAS), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6PDH) were assessed. The CGHA diet had the highest amount of BCAAs, especially leucine, and most of them existed as free amino acid forms. The CGHA group showed significant weight reduction and negative nitrogen balance. Protein absorption and apparent protein digestibility in the CGHA group were significantly lower than those in other groups. Adipose tissue weights were the lowest in the CGHA group. Activity of CPT tended to be higher in the CGHA group than in other groups and those of FAS, ME and G6PDH were significantly lower in the CGHA group than in other groups. In conclusion, the CGHA diet which had relatively high amounts of free amino acids and BCAAs, especially leucine, had a weight reduction effect by lowering adipose tissue weight and the activities of FAS, ME and G6PDH in experimental animals, but it seemed to be a negative result induced by lowering protein absorption, increasing urinary nitrogen excretion and protein catabolism.

• Animal Bioscience
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• 제37권7호
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• pp.1289-1302
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• 2024

Objective: There is a strong relationship between the content of beneficial fatty acids in milk and milk fat metabolic activity in the mammary gland. To improve milk quality, it is therefore necessary to study fatty acid metabolism in bovine mammary gland tissue. In adipose tissue, peroxisome proliferator-activated receptor gamma (PPARG), the core transcription factor, regulates the fatty acid metabolism gene network and determines fatty acid deposition. However, its regulatory effects on mammary gland fatty acid metabolism during lactation have rarely been reported. Methods: Transcriptome sequencing was performed during the prelactation period and the peak lactation period to examine mRNA expression. The significant upregulation of PPARG drew our attention and led us to conduct further research. Results: According to bioinformatics prediction, dual-luciferase reporter system detection, real-time quantitative reverse transcription polymerase chain reaction and Western blotting, miR-130a and miR-130b could directly target PPARG and inhibit its expression. Furthermore, triglyceride and oil red O staining proved that miR-130a and miR-130b inhibited milk fat metabolism in bovine mammary epithelial cells (BMECs), while PPARG promoted this metabolism. In addition, we also found that the coexpression of miR-130a and miR-130b significantly enhanced their ability to regulate milk fat metabolism. Conclusion: In conclusion, our findings indicated that miR-130a and miR-130b could target and repress PPARG and that they also have a functional superposition effect. miR-130a and miR-130b seem to synergistically regulate lipid catabolism via the control of PPARG in BMECs. In the long-term, these findings might be helpful in developing practical means to improve high-quality milk.

• Nutritional Sciences
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• 제9권3호
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• pp.179-189
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• 2006

Objective: We investigated the efficacy of a 12-week supplementation of soy isoflavone with L-carnitine on the development of obesity in high fat-induced obese C57BL/6J mice, which are known as a good model of diet-induced obesity. Methods: We measured body weights, adipose tissue mass, serum/liver lipid profiles and fat cell size/number in C57BL/6J mice fed diets containing either low fat (4%) or high fat (35%), or high fat supplemented with soy isoflavone powder containing 10% isoflavone and L-camitine for 12 weeks. Results: Body weight gain, abdominal adipose tissue and liver weight were lower by 31% 78% and 31.4% respectively, in mice on high fat diet containing soy isoflavone+L-carnitine (SC mixture) compared with high fat diet group. Also, SC mixture improved serum lipid profiles such as total cholesterol (TC), triglycerides (TG), and liver lipid profiles such as total lipids and TG. As subsequent results, this SC mixture prevented high-fat diet from accumulating TG in the liver. The size of fat cell was also significantly decreased in SC mixture fed mice. At the end point of this experiment, our results showed that feeding with soy isoflavone for 12 weeks finally increased camitine palmitoyltransferase 1 (CPT 1) activity through elevating the level of CPT1 expression. Conclusions: This study suggests that long-tenn supplementation with dietary soy isoflavone and L-carnitine is more synergistically beneficial for the suppression of high-fat diet induced obesity by inhibiting liver TG accumulation and the gain in abdominal adipose tissue weight than that with soy isoflavone. The antiobesity effects of SC mixture might be attributed, at least in part, to the induction of fatty acid catabolism by soy isoflavone, genistein.

• Asian-Australasian Journal of Animal Sciences
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• 제21권2호
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• pp.167-176
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• 2008

Galectins are a group of animal lectins consisting of galectin-type carbohydrate recognition domains (CRD) with relatively minor domains. The biological properties of galectins include the regulation of inflammation, intercellular adhesion, cell differentiation and cell death. The diverse kinds of galectin suggest variety in their biological roles. Galectin-1 is released during adipocyte differentiation and is associated with fat which is one of the important factors for meat quality. To verify expression level, a 0.5 kb clone of galectin-1 was obtained from cDNA prepared from back fat tissue of a Sancheong Berkshire pig with good quality meat, and the galectin-1 gene identified. The deduced amino acid sequence of the galectin-1 gene was compared with those obtained from other species. By using RT-PCR and Real time-PCR, an attempt was made to determine the expression level of galectin-1 and to compare with various tissues (tenderloin and back fat) taken from pigs in different groups. Grouping of pigs was based on growth-stage (weighing 60, 80, and 110 kg) and the sub-speciation (Yorkshire and Sancheong Berkshire pigs). We attempted to determine influences of pig species, growth stages and tissue variations on the expression level of the galectin-l gene and it was revealed that the expression pattern of the galectin-1 gene was significantly different (p<0.01 or p<0.05). Galectin-1 genes were expressed more highly in the back fat tissues of pigs weighing 110 kg than in those weighing 60 kg or 80 kg. However, the lowest expression was seen in the tenderloin tissues of pigs weighing 110 kg. Sancheong Berkshire pigs showed higher expression of the galectin-1 gene compared to Yorkshire pigs. Accordingly, it is considered that the expression pattern of the galectin-1 gene influences the growth of back fat tissues and the pig speciation relationship. Previous studies suggested that different expression of galectin-1 genes represents variety among the breeds and is closely related to fat tissue growth, conjugation and catabolism. Further, this study suggests that the expression of galectin-1 at a specific growth stage and tissue contributes significantly to the overall meat quality of Sancheong Berkshire pigs.

• 한방재활의학과학회지
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• 제32권2호
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• pp.19-36
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• 2022

Objectives This study is to investigate the effects and mechanisms of Imyo-san (IMS) on the obese mice model induced by high-fat diet. Methods Antioxidative capacity was measured by in vitro method. C57BL/6 mice were randomly assigned into 5 groups (n=7). Normal group was fed general diet (Normal). The other 4 groups were fed high fat diet (HFD) with water (Control), with Garcinia gummi-gutta (GG, Garcinia gummi-gutta 200 mg/kg), with low-dose IMS (IMSL, Imyo-san 0.54 g/kg) and with high-dose IMS (IMSH, Imyo-san 1.08 g/kg). Results IMS showed high radical scavenging activity. After 6 week experiment, body weight, food intake, food efficiency ratio (FER), epididymal fat and liver weight, triglyceride (TG), total cholesterol (TC), high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, very low density lipoprotein (VLDL) cholesterol, sterol regulatory element-binding protein-1 (SREBP-1), phospho-acetyl-CoA carboxylase (p-ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase-1 (SCD-1), SREBP-2, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), phospho-liver kinase B1 (p-LKB1), phospho-AMP-activated protein kinase (p-AMPK), peroxisome proliferator-activated receptor 𝛼 (PPAR𝛼), peroxisome proliferator-activated receptor 𝛾 coactivator-1𝛼 (PGC-1𝛼), uncoupling protein-2 (UCP-2), carnitine palmitoyltransferase 1A (CPT-1A), and histology of liver and epididymal fat were measured and analysed. Body weight gain, FER, liver and epididymal fat weight of IMS groups were significantly decreased. There were significant improvements in blood lipids with less TG, TC, LDL-cholesterol, VLDL-cholesterol and more HDL-cholesterol. Proteins associated with lipid synthesis (SREBP-1, p-ACC, FAS, SCD-1) and cholesterol (SREBP-2, HMGCR) was improved. Factors regulating lipid synthesis and lipid catabolism (p-LKBI, p-AMPK, PPARα, PGC-1α, UCP-2, CPT-1A) were increased. In histological examinations, IMS group had smaller fat droplets than control group. All results increased depending on concentration. Conclusions It can be suggested that IMS has anti-obesity effects with improving lipid metabolism.

• Asian-Australasian Journal of Animal Sciences
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• 제29권11호
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• pp.1593-1600
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• 2016

This research was conducted to investigate the physiological consequences of undernourished yak. Twelve Maiwa yak ($110.3{\pm}5.85kg$) were randomly divided into two groups (baseline and starvation group). The yak of baseline group were slaughtered at day 0, while the other group of yak were kept in shed without feed but allowed free access to water, salt and free movement for 9 days. Blood samples of the starvation group were collected on day 0, 1, 2, 3, 5, 7, 9 and the starved yak were slaughtered after the final blood sample collection. The liver and muscle glycogen of the starvation group decreased (p<0.01), and the lipid content also decreased while the content of moisture and ash increased (p<0.05) both in Longissimus dorsi and liver compared with the baseline group. The plasma insulin and glucose of the starved yak decreased at first and then kept stable but at a relatively lower level during the following days (p<0.01). On the contrary, the non-esterified fatty acids was increased (p<0.01). Beyond our expectation, the ketone bodies of ${\beta}$-hydroxybutyric acid and acetoacetic acid decreased with prolonged starvation (p<0.01). Furthermore, the mRNA expression of lipogenetic enzyme fatty acid synthase and lipoprotein lipase in subcutaneous adipose tissue of starved yak were down-regulated (p<0.01), whereas the mRNA expression of lipolytic enzyme carnitine palmitoyltransferase-1 and hormone sensitive lipase were up-regulated (p<0.01) after 9 days of starvation. The phosphoenolpyruvate carboxykinase and pyruvate carboxylase, responsible for hepatic gluconeogenesis were up-regulated (p<0.01). It was concluded that yak derive energy by gluconeogenesis promotion and fat storage mobilization during starvation but without ketone body accumulation in the plasma.