Maryline Kouba - Academia.edu (original) (raw)

Papers by Maryline Kouba

Research paper thumbnail of Lipogenesis in turkeys and chickens: A study of body composition and liver lipogenic enzyme activities

British Poultry Science, 1992

1. Carcase composition, fat deposition and the activities of three liver lipogenic enzymes were c... more 1. Carcase composition, fat deposition and the activities of three liver lipogenic enzymes were compared in turkeys and chickens fed ad libitum on two different isocaloric diets, respectively adapted to chickens (C) and to turkeys (T). Diets differed in their protein content, being higher by 60 g/kg in diet T.2. Chickens were much fatter than turkeys and exhibited higher activities of acetyl‐coenzyme A carboxylase (EC 6.4.1.2) and malic enzyme (EC 1.1.1.40).3. The carcase composition of turkeys was not influenced by the type of diet administered, while chickens fed on diet C were fatter than chickens fed on diet T. Compared to diet T, diet C enhanced malic enzyme activity, whatever the species and age.4. A good correlation between abdominal fat and total fatness was observed in both species but especially in turkeys.5. In conclusion, hepatic lipogenesis is much lower in turkeys than in chickens.

Research paper thumbnail of Tissue distribution in pig carcasses exhibiting large differences in their degree of leanness, with special emphasis on intermuscular fat

Livestock Production Science, 2005

Tissue distribution in pig carcasses was studied in pigs from seven genotype–sex groups with larg... more Tissue distribution in pig carcasses was studied in pigs from seven genotype–sex groups with large variations in body composition. The animals were slaughtered at 115 kg live weight, and the left side carcass was separated into four primal cuts: belly, shoulder, loin and ham. Each primal cut was dissected into muscle, bone, skin, subcutaneous fat and intermuscular fat. The negative

Research paper thumbnail of Comparative study of in vitro lipogenesis in various adipose tissues in the growing meishan pig: Comparison with the large white pig ( Sus domesticus

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1996

Activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate-dehydrogenase were mea... more Activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate-dehydrogenase were measured in seven different anatomical sites in the growing pig (20-120 kg weight). The three enzyme activities increased up to 40-60 kg weight and then decreased, malic enzyme becoming the main producer of NADPH, irrespective of the adipose tissue. Subcutaneous adipose tissue of the neck area was much thicker and exhibited much lower lipogenic enzyme activities than backfat. Subcutaneous adipose tissue is heterogeneous in the pig with some areas exhibiting very low lipogenesis and high lipid deposition importing triglycerides from other areas with high lipogenesis. However, these conclusions based on the measurement of enzyme activity potentials need to be confirmed with measurements of actual activities.

Research paper thumbnail of Effect of a high linoleic acid diet on Δ9-desaturase activity, lipogenesis and lipid composition of pig subcutaneous adipose tissue

Reproduction Nutrition Development, 1998

The effects of three diets were compared: a high linoleic acid diet (diet M containing 4% maize o... more The effects of three diets were compared: a high linoleic acid diet (diet M containing 4% maize oil), diet T containing 4% beef tallow, and C, a conventional control diet, on delta 9-desaturase activity and lipogenesis in pig subcutaneous adipose tissue. Diet M increased lipogenesis (estimated from the activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate dehydrogenase), and decreased delta 9-desaturase activity, in comparison to the other diets. Linoleic acid content was higher in the pigs fed diet M than in the other pigs (amounting to 26% of total tissue fatty acids versus 15%, respectively). The lower monounsaturated fatty acid content in adipose tissue of pigs fed diet M compared to pigs fed other diets could be associated with the lower delta 9-desaturase activity and the lower oleic acid content of diet M. The present study suggests that delta 9-desaturase could be involved in the regulation of monounsaturated fatty acid content and hence in the quality of pig adipose tissue.

Research paper thumbnail of A review of nutritional effects on fat composition of animal products with special emphasis on n-3 polyunsaturated fatty acids

Biochimie, 2011

The fatty acid composition of animal products (eggs, milk and meat) is the reflect of both the ti... more The fatty acid composition of animal products (eggs, milk and meat) is the reflect of both the tissue fatty acid biosynthesis and the fatty acid composition of ingested lipids. This relationship is stronger in monogastrics (pigs, poultry and rabbits) than in ruminants, where dietary fatty acids are hydrogenated in the rumen. There is an increasing recognition of the health benefits of polyunsaturated fatty acids (PUFA), because these fatty acids are essential for humans. In addition, the ratio n-6/n-3 fatty acids in the human diet is important. This ratio by far exceeds the recommended value of 5. Therefore, inclusion of fish meals, or n-3 PUFA rich oils, or linseed in animal diets is a valid means of meeting consumer demand for animal products that are nutritionally beneficial. The studies that are undertaken on animals mainly use diets supplemented with linseed, as a source of n-3 fatty acids. The use of linseed diets generally leads to an increased n-3 fatty acid content in animal products (egg, meat, milk) in ruminants and monogastrics. Recent studies have also demonstrated that neither the processing nor the cooking affects the PUFA content of pork meat or meat products. The ability of unsaturated fatty acids, especially those with more than two double bonds, to rapidly oxidise, is important in regulating the shelf life of animal products (rancidity and colour deterioration); however, a good way to avoid such problems is to use antioxidant products (such as vitamin E) in the diet. Some studies also show that it is not necessary to feed animals with linseed-supplemented diets for a long time to have the highest increase in PUFA content of the products. So, short-term diet manipulation can be a practical reality for industry. As the market for n-3 PUFA enriched products is today limited in most countries, other studies must be undertaken to develop this kind of production.

Research paper thumbnail of Stearoyl-CoA Desaturase Activity in Adipose Tissues and Liver of Growing Large White and Meishan Pigs

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1997

Stearoyl-CoA desaturase activity was measured in adipose tissue (backfat and neckfat) and liver m... more Stearoyl-CoA desaturase activity was measured in adipose tissue (backfat and neckfat) and liver microsomes of Large White and Meishan pigs. Preliminary assays have shown that delta 9-desaturase activity cannot be measured on frozen tissues, because freezing involves a loss in activity of 40-50%. The specific activity of liver delta 9-desaturase was much lower than that of the adipose tissues in both breeds, indicating that the liver is not a major site of oleate synthesis in the pig. The hepatic delta 9-desaturase activity was higher in Meishan than in Large White pigs. However, delta 9-desaturase activity in the adipose tissue of Large White pigs was much higher than that of Meishan pigs, even though the percentage of oleate was slightly higher in the adipose tissues of the latter. This investigation has demonstrated that differences in fatty acid composition of adipose tissues between Large White and Meishan pigs cannot be attributed to differences in delta 9-desaturase activity at this stage of maturity. These results suggest that the higher oleate percentage in Meishan adipose tissues would result from a higher delta 9-desaturase activity at an earlier age.

Research paper thumbnail of Comparative study of in vitro lipogenesis in various adipose tissues in the growing domestic pig ( Sus domesticus

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1995

Activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate-dehydrogenase were mea... more Activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate-dehydrogenase were measured in seven different anatomical sites in the growing pig (20-120 kg weight). The three enzyme activities increased up to 40-60 kg weight and then decreased, malic enzyme becoming the main producer of NADPH, irrespective of the adipose tissue. Subcutaneous adipose tissue of the neck area was much thicker and exhibited much lower lipogenic enzyme activities than backfat. Subcutaneous adipose tissue is heterogeneous in the pig with some areas exhibiting very low lipogenesis and high lipid deposition importing triglycerides from other areas with high lipogenesis. However, these conclusions based on the measurement of enzyme activity potentials need to be confirmed with measurements of actual activities.

Research paper thumbnail of Effect of a linseed diet or a sunflower diet on performances, fatty acid composition, lipogenic enzyme activities and stearoyl-CoA-desaturase activity in the pig

Livestock Science, 2009

The aim of this study was to compare the influence of a high α-linolenic acid (ALA) diet (linseed... more The aim of this study was to compare the influence of a high α-linolenic acid (ALA) diet (linseed diet) and a high linoleic acid (LA) diet (sunflower diet) on performances of pigs, on the dietetical quality of their tissues (adipose tissues and muscles), and on the lipogenic potential of these tissues. Growth and carcass performances, and the lipid content of the tissues were not affected by the diet. Feeding the linseed diet increased the content of n-3 PUFA and decreased the LA/ALA ratios in all the tissues, while the sunflower diet led to an increase in the n-6 PUFA contents. Neither the stearoyl-CoA-desaturase and glucose-6-phosphate-dehydrogenase activities nor the β-hydroxyacyl-CoA-dehydrogenase activity were affected by the diet. Acetyl-CoA-carboxylase and fatty acid synthase activities were enhanced with the linseed diet in respectively subcutaneous adipose tissue and intermuscular adipose tissue, while malic enzyme activity was decreased in liver and subcutaneous adipose tissue of pigs fed the linseed diet.

Research paper thumbnail of Liver stearyl-CoA desaturase activity and fatness in birds. In vitro studies in the growing turkey and chicken

Comparative Biochemistry and Physiology Part A: Physiology, 1993

l. Liver stearyl-CoA desaturase activity and total body fat were measured in 4-, 8and 12-week-old... more l. Liver stearyl-CoA desaturase activity and total body fat were measured in 4-, 8and 12-week-old turkeys and chickens reared together and fed either of two isocaloric diets differing in their protein content.

Research paper thumbnail of A review of the factors influencing the development of intermuscular adipose tissue in the growing pig

Fuel and Energy Abstracts, 2011

Compared with subcutaneous or abdominal fat depots of pig carcasses, intermuscular fat displays a... more Compared with subcutaneous or abdominal fat depots of pig carcasses, intermuscular fat displays a number of original properties. It cannot be easily removed from fresh or processed meat delivered to consumers and has therefore an influence on consumer acceptability of pork. Particular compositional characteristics of intermuscular fat include low lipid content and small size of adipocytes. How age (or body weight), gender, castration, environmental temperature, feeding restriction, diet composition, as well as genetic factors affect intermuscular fat development and composition are surveyed in this review paper. Up to now, few studies have specifically dealt with the intermuscular compartment of body fat while very abundant information is available on the subcutaneous one. As a general rule, any factor, either genetic or non-genetic, which causes a decrease of whole carcass fat deposition generates a higher relative importance of the intermuscular fraction of total fat as well as an increased degree of unsaturation of constituent fatty acids.

Research paper thumbnail of Effect of genetic and nutritional factors on Δ9 desaturase activity in hepatic and adipose tissues in the pig

Reproduction Nutrition Development, 1999

Research paper thumbnail of Lipogenic enzyme activities in muscles of growing Large White and Meishan pigs

Livestock Production Science, 1998

We compared the activities of acetyl-CoA-carboxylase (ACX), malic enzyme (ME) and glucose-6-phosp... more We compared the activities of acetyl-CoA-carboxylase (ACX), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6-PDH) in the muscles of growing Large White (LW) and Meishan (MS) pigs. In Exp. 1, adipocytes were isolated from Semimembranosus and Diaphragma muscles of six 60-kg LW pigs, and enzyme activities were compared in isolated adipocytes and in muscle homogenates. More than 80% of ACX and

Research paper thumbnail of Development of intra- and intermuscular adipose tissue in growing Large White and Meishan pigs

Reproduction Nutrition Development, 1999

Lipogenic enzyme activities of porcine intra- and intermuscular adipose tissues were determined i... more Lipogenic enzyme activities of porcine intra- and intermuscular adipose tissues were determined in growing lean (Large White) and fat (Meishan) pigs. The activities of acetyl-CoA-carboxylase (ACX), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6PDH) were compared in both breeds and at both adipose sites. All three enzyme activities were much lower in the intramuscular adipose tissue than in the intermuscular site. Although the lipogenic activity of the intramuscular adipose site was low, it appeared, however, to possess adequate levels of enzymes for in situ lipid synthesis. The highest differences in lipogenic enzyme activities between Meishan and Large White pigs were found in intramuscular adipose tissue, and essentially concerned the activity of malic enzyme which was much higher in Meishan pigs. A close relationship between ME activity and lipid content of intramuscular adipose tissue was observed in both breeds. It was concluded that ME appeared to be a major factor affecting the incidence of higher intramuscular fat in the pig.

Research paper thumbnail of In vivo hepatic secretion of very low density lipoproteins in the growing turkey and chicken treated with an anti-lipoprotein lipase serum

Reproduction Nutrition Development, 1994

Research paper thumbnail of Effect of dietary fats on hepatic lipid metabolism in the growing turkey

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 2002

The influence of dietary fatty acids on hepatic capacity of lipid synthesis and secretion was inv... more The influence of dietary fatty acids on hepatic capacity of lipid synthesis and secretion was investigated in 7-weekold male turkeys. They were fed 10% of either lard (rich in saturated and monounsaturated fatty acids) or linseed oil (rich in polyunsaturated fatty acids, especially 18:3n-3). Fattening was identical with both diets (0.15-0.20% of abdominal adipose tissue), but the proportion of muscle Pectoralis major was lower with linseed oil (6.6 vs. 7.4%). Specific activities of lipogenic enzymes (ME, G6PDH, ACX, and D9-desaturase) were not influenced by the diet, however, FAS activity was lower with linseed oil (14.3 vs. 25.4 nM NADPH fixedymin). Fasting concentrations of lipoproteins synthesized and secreted by the liver, VLDL and HDL, were also lower with linseed oil, as well as plasma concentrations of phospholipids and cholesteryl esters. However, when VLDL catabolism was inhibited by injection of an antiserum against LPL, VLDL concentration was identical in both groups (100-120 mgyl), whereas that of phospholipids and cholesteryl esters, that are transported by HDL mainly, remained lower with linseed oil. Thus, in the growing turkeys, and contrary to mammals and the chicken, feeding n-3 polyunsaturated fatty acids did not decrease hepatic triglyceride synthesis and secretion, nor fattening. By contrast, in this species, n-3 polyunsaturated fatty acids appear to influence mostly HDL metabolism, with a negative impact on muscular growth. ᮊ

Research paper thumbnail of Comparative study of hepatic VLDL secretion in vivo in the growing turkey ( Meleagris gallopavo) and chicken ( Gallus domesticus

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1995

Hepatic secretion of VLDL was compared in young turkeys and chickens (8 and 4 weeks of age, respe... more Hepatic secretion of VLDL was compared in young turkeys and chickens (8 and 4 weeks of age, respectively) and older birds (11 and 8 weeks of age, respectively) reared together under the same nutritional conditions. VLDL, VLDL-TG and total TG secretion rates were higher in chickens than in turkeys. The cholesteryl ester content of turkey VLDL was higher than that of chicken. Differences in the fatty acid composition of the VLDL lipids were observed between the species: the proportion of linoleic acid was greater in turkeys, whereas monounsaturated fatty acids were more abundant in chickens. These results are consistent with the hypothesis of a positive relationship between hepatic lipogenesis, deita-9desaturation, VLDL secretion and fattening in turkeys and chickens.

Research paper thumbnail of Influence of a high ambient temperature on stearoyl-CoA-desaturase activity in the growing pig

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1999

An experiment was conducted to determine the influence of a high ambient temperature on the stear... more An experiment was conducted to determine the influence of a high ambient temperature on the stearoyl-CoA-desaturase activity and fatty acid composition of backfat, leaf fat, Longissimus dorsi muscle and liver, in the growing pig. Eighteen Large White X Landrace castrated pigs (20 kg body weight) were divided into three groups: I (31 degrees C, ad libitum), II (20 degrees C, pair-fed on the 31 degrees C group) and III (20 degrees C, ad libitum) until 35 kg body weight. At 20 degrees C, the level of feed intake had no effect on stearoyl-CoA-desaturase activity, whatever the tissue (groups II and III). At similar levels of feeding, (groups I and II), the stearoyl-CoA-desaturase activity was lower at 31 degrees C (P < 0.001) than at 20 degrees C, regardless of the tissue, with the exception of the hepatic stearoyl-CoA-desaturase activity, which was similar in all three groups. This reduction of the stearoyl-CoA-desaturase activity at 31 degrees C could be related to a decrease in the monounsaturated fatty acid percentage in all the tissues, in hot conditions. The present results show that changes in fatty acid composition caused by environmental temperature, in the pig, may be attributed at least in part to an alteration in the stearoyl-CoA-desaturase activity.

Research paper thumbnail of Lipogenesis in turkeys and chickens: A study of body composition and liver lipogenic enzyme activities

British Poultry Science, 1992

1. Carcase composition, fat deposition and the activities of three liver lipogenic enzymes were c... more 1. Carcase composition, fat deposition and the activities of three liver lipogenic enzymes were compared in turkeys and chickens fed ad libitum on two different isocaloric diets, respectively adapted to chickens (C) and to turkeys (T). Diets differed in their protein content, being higher by 60 g/kg in diet T.2. Chickens were much fatter than turkeys and exhibited higher activities of acetyl‐coenzyme A carboxylase (EC 6.4.1.2) and malic enzyme (EC 1.1.1.40).3. The carcase composition of turkeys was not influenced by the type of diet administered, while chickens fed on diet C were fatter than chickens fed on diet T. Compared to diet T, diet C enhanced malic enzyme activity, whatever the species and age.4. A good correlation between abdominal fat and total fatness was observed in both species but especially in turkeys.5. In conclusion, hepatic lipogenesis is much lower in turkeys than in chickens.

Research paper thumbnail of Tissue distribution in pig carcasses exhibiting large differences in their degree of leanness, with special emphasis on intermuscular fat

Livestock Production Science, 2005

Tissue distribution in pig carcasses was studied in pigs from seven genotype–sex groups with larg... more Tissue distribution in pig carcasses was studied in pigs from seven genotype–sex groups with large variations in body composition. The animals were slaughtered at 115 kg live weight, and the left side carcass was separated into four primal cuts: belly, shoulder, loin and ham. Each primal cut was dissected into muscle, bone, skin, subcutaneous fat and intermuscular fat. The negative

Research paper thumbnail of Comparative study of in vitro lipogenesis in various adipose tissues in the growing meishan pig: Comparison with the large white pig ( Sus domesticus

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1996

Activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate-dehydrogenase were mea... more Activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate-dehydrogenase were measured in seven different anatomical sites in the growing pig (20-120 kg weight). The three enzyme activities increased up to 40-60 kg weight and then decreased, malic enzyme becoming the main producer of NADPH, irrespective of the adipose tissue. Subcutaneous adipose tissue of the neck area was much thicker and exhibited much lower lipogenic enzyme activities than backfat. Subcutaneous adipose tissue is heterogeneous in the pig with some areas exhibiting very low lipogenesis and high lipid deposition importing triglycerides from other areas with high lipogenesis. However, these conclusions based on the measurement of enzyme activity potentials need to be confirmed with measurements of actual activities.

Research paper thumbnail of Effect of a high linoleic acid diet on Δ9-desaturase activity, lipogenesis and lipid composition of pig subcutaneous adipose tissue

Reproduction Nutrition Development, 1998

The effects of three diets were compared: a high linoleic acid diet (diet M containing 4% maize o... more The effects of three diets were compared: a high linoleic acid diet (diet M containing 4% maize oil), diet T containing 4% beef tallow, and C, a conventional control diet, on delta 9-desaturase activity and lipogenesis in pig subcutaneous adipose tissue. Diet M increased lipogenesis (estimated from the activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate dehydrogenase), and decreased delta 9-desaturase activity, in comparison to the other diets. Linoleic acid content was higher in the pigs fed diet M than in the other pigs (amounting to 26% of total tissue fatty acids versus 15%, respectively). The lower monounsaturated fatty acid content in adipose tissue of pigs fed diet M compared to pigs fed other diets could be associated with the lower delta 9-desaturase activity and the lower oleic acid content of diet M. The present study suggests that delta 9-desaturase could be involved in the regulation of monounsaturated fatty acid content and hence in the quality of pig adipose tissue.

Research paper thumbnail of A review of nutritional effects on fat composition of animal products with special emphasis on n-3 polyunsaturated fatty acids

Biochimie, 2011

The fatty acid composition of animal products (eggs, milk and meat) is the reflect of both the ti... more The fatty acid composition of animal products (eggs, milk and meat) is the reflect of both the tissue fatty acid biosynthesis and the fatty acid composition of ingested lipids. This relationship is stronger in monogastrics (pigs, poultry and rabbits) than in ruminants, where dietary fatty acids are hydrogenated in the rumen. There is an increasing recognition of the health benefits of polyunsaturated fatty acids (PUFA), because these fatty acids are essential for humans. In addition, the ratio n-6/n-3 fatty acids in the human diet is important. This ratio by far exceeds the recommended value of 5. Therefore, inclusion of fish meals, or n-3 PUFA rich oils, or linseed in animal diets is a valid means of meeting consumer demand for animal products that are nutritionally beneficial. The studies that are undertaken on animals mainly use diets supplemented with linseed, as a source of n-3 fatty acids. The use of linseed diets generally leads to an increased n-3 fatty acid content in animal products (egg, meat, milk) in ruminants and monogastrics. Recent studies have also demonstrated that neither the processing nor the cooking affects the PUFA content of pork meat or meat products. The ability of unsaturated fatty acids, especially those with more than two double bonds, to rapidly oxidise, is important in regulating the shelf life of animal products (rancidity and colour deterioration); however, a good way to avoid such problems is to use antioxidant products (such as vitamin E) in the diet. Some studies also show that it is not necessary to feed animals with linseed-supplemented diets for a long time to have the highest increase in PUFA content of the products. So, short-term diet manipulation can be a practical reality for industry. As the market for n-3 PUFA enriched products is today limited in most countries, other studies must be undertaken to develop this kind of production.

Research paper thumbnail of Stearoyl-CoA Desaturase Activity in Adipose Tissues and Liver of Growing Large White and Meishan Pigs

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1997

Stearoyl-CoA desaturase activity was measured in adipose tissue (backfat and neckfat) and liver m... more Stearoyl-CoA desaturase activity was measured in adipose tissue (backfat and neckfat) and liver microsomes of Large White and Meishan pigs. Preliminary assays have shown that delta 9-desaturase activity cannot be measured on frozen tissues, because freezing involves a loss in activity of 40-50%. The specific activity of liver delta 9-desaturase was much lower than that of the adipose tissues in both breeds, indicating that the liver is not a major site of oleate synthesis in the pig. The hepatic delta 9-desaturase activity was higher in Meishan than in Large White pigs. However, delta 9-desaturase activity in the adipose tissue of Large White pigs was much higher than that of Meishan pigs, even though the percentage of oleate was slightly higher in the adipose tissues of the latter. This investigation has demonstrated that differences in fatty acid composition of adipose tissues between Large White and Meishan pigs cannot be attributed to differences in delta 9-desaturase activity at this stage of maturity. These results suggest that the higher oleate percentage in Meishan adipose tissues would result from a higher delta 9-desaturase activity at an earlier age.

Research paper thumbnail of Comparative study of in vitro lipogenesis in various adipose tissues in the growing domestic pig ( Sus domesticus

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1995

Activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate-dehydrogenase were mea... more Activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate-dehydrogenase were measured in seven different anatomical sites in the growing pig (20-120 kg weight). The three enzyme activities increased up to 40-60 kg weight and then decreased, malic enzyme becoming the main producer of NADPH, irrespective of the adipose tissue. Subcutaneous adipose tissue of the neck area was much thicker and exhibited much lower lipogenic enzyme activities than backfat. Subcutaneous adipose tissue is heterogeneous in the pig with some areas exhibiting very low lipogenesis and high lipid deposition importing triglycerides from other areas with high lipogenesis. However, these conclusions based on the measurement of enzyme activity potentials need to be confirmed with measurements of actual activities.

Research paper thumbnail of Effect of a linseed diet or a sunflower diet on performances, fatty acid composition, lipogenic enzyme activities and stearoyl-CoA-desaturase activity in the pig

Livestock Science, 2009

The aim of this study was to compare the influence of a high α-linolenic acid (ALA) diet (linseed... more The aim of this study was to compare the influence of a high α-linolenic acid (ALA) diet (linseed diet) and a high linoleic acid (LA) diet (sunflower diet) on performances of pigs, on the dietetical quality of their tissues (adipose tissues and muscles), and on the lipogenic potential of these tissues. Growth and carcass performances, and the lipid content of the tissues were not affected by the diet. Feeding the linseed diet increased the content of n-3 PUFA and decreased the LA/ALA ratios in all the tissues, while the sunflower diet led to an increase in the n-6 PUFA contents. Neither the stearoyl-CoA-desaturase and glucose-6-phosphate-dehydrogenase activities nor the β-hydroxyacyl-CoA-dehydrogenase activity were affected by the diet. Acetyl-CoA-carboxylase and fatty acid synthase activities were enhanced with the linseed diet in respectively subcutaneous adipose tissue and intermuscular adipose tissue, while malic enzyme activity was decreased in liver and subcutaneous adipose tissue of pigs fed the linseed diet.

Research paper thumbnail of Liver stearyl-CoA desaturase activity and fatness in birds. In vitro studies in the growing turkey and chicken

Comparative Biochemistry and Physiology Part A: Physiology, 1993

l. Liver stearyl-CoA desaturase activity and total body fat were measured in 4-, 8and 12-week-old... more l. Liver stearyl-CoA desaturase activity and total body fat were measured in 4-, 8and 12-week-old turkeys and chickens reared together and fed either of two isocaloric diets differing in their protein content.

Research paper thumbnail of A review of the factors influencing the development of intermuscular adipose tissue in the growing pig

Fuel and Energy Abstracts, 2011

Compared with subcutaneous or abdominal fat depots of pig carcasses, intermuscular fat displays a... more Compared with subcutaneous or abdominal fat depots of pig carcasses, intermuscular fat displays a number of original properties. It cannot be easily removed from fresh or processed meat delivered to consumers and has therefore an influence on consumer acceptability of pork. Particular compositional characteristics of intermuscular fat include low lipid content and small size of adipocytes. How age (or body weight), gender, castration, environmental temperature, feeding restriction, diet composition, as well as genetic factors affect intermuscular fat development and composition are surveyed in this review paper. Up to now, few studies have specifically dealt with the intermuscular compartment of body fat while very abundant information is available on the subcutaneous one. As a general rule, any factor, either genetic or non-genetic, which causes a decrease of whole carcass fat deposition generates a higher relative importance of the intermuscular fraction of total fat as well as an increased degree of unsaturation of constituent fatty acids.

Research paper thumbnail of Effect of genetic and nutritional factors on Δ9 desaturase activity in hepatic and adipose tissues in the pig

Reproduction Nutrition Development, 1999

Research paper thumbnail of Lipogenic enzyme activities in muscles of growing Large White and Meishan pigs

Livestock Production Science, 1998

We compared the activities of acetyl-CoA-carboxylase (ACX), malic enzyme (ME) and glucose-6-phosp... more We compared the activities of acetyl-CoA-carboxylase (ACX), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6-PDH) in the muscles of growing Large White (LW) and Meishan (MS) pigs. In Exp. 1, adipocytes were isolated from Semimembranosus and Diaphragma muscles of six 60-kg LW pigs, and enzyme activities were compared in isolated adipocytes and in muscle homogenates. More than 80% of ACX and

Research paper thumbnail of Development of intra- and intermuscular adipose tissue in growing Large White and Meishan pigs

Reproduction Nutrition Development, 1999

Lipogenic enzyme activities of porcine intra- and intermuscular adipose tissues were determined i... more Lipogenic enzyme activities of porcine intra- and intermuscular adipose tissues were determined in growing lean (Large White) and fat (Meishan) pigs. The activities of acetyl-CoA-carboxylase (ACX), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6PDH) were compared in both breeds and at both adipose sites. All three enzyme activities were much lower in the intramuscular adipose tissue than in the intermuscular site. Although the lipogenic activity of the intramuscular adipose site was low, it appeared, however, to possess adequate levels of enzymes for in situ lipid synthesis. The highest differences in lipogenic enzyme activities between Meishan and Large White pigs were found in intramuscular adipose tissue, and essentially concerned the activity of malic enzyme which was much higher in Meishan pigs. A close relationship between ME activity and lipid content of intramuscular adipose tissue was observed in both breeds. It was concluded that ME appeared to be a major factor affecting the incidence of higher intramuscular fat in the pig.

Research paper thumbnail of In vivo hepatic secretion of very low density lipoproteins in the growing turkey and chicken treated with an anti-lipoprotein lipase serum

Reproduction Nutrition Development, 1994

Research paper thumbnail of Effect of dietary fats on hepatic lipid metabolism in the growing turkey

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 2002

The influence of dietary fatty acids on hepatic capacity of lipid synthesis and secretion was inv... more The influence of dietary fatty acids on hepatic capacity of lipid synthesis and secretion was investigated in 7-weekold male turkeys. They were fed 10% of either lard (rich in saturated and monounsaturated fatty acids) or linseed oil (rich in polyunsaturated fatty acids, especially 18:3n-3). Fattening was identical with both diets (0.15-0.20% of abdominal adipose tissue), but the proportion of muscle Pectoralis major was lower with linseed oil (6.6 vs. 7.4%). Specific activities of lipogenic enzymes (ME, G6PDH, ACX, and D9-desaturase) were not influenced by the diet, however, FAS activity was lower with linseed oil (14.3 vs. 25.4 nM NADPH fixedymin). Fasting concentrations of lipoproteins synthesized and secreted by the liver, VLDL and HDL, were also lower with linseed oil, as well as plasma concentrations of phospholipids and cholesteryl esters. However, when VLDL catabolism was inhibited by injection of an antiserum against LPL, VLDL concentration was identical in both groups (100-120 mgyl), whereas that of phospholipids and cholesteryl esters, that are transported by HDL mainly, remained lower with linseed oil. Thus, in the growing turkeys, and contrary to mammals and the chicken, feeding n-3 polyunsaturated fatty acids did not decrease hepatic triglyceride synthesis and secretion, nor fattening. By contrast, in this species, n-3 polyunsaturated fatty acids appear to influence mostly HDL metabolism, with a negative impact on muscular growth. ᮊ

Research paper thumbnail of Comparative study of hepatic VLDL secretion in vivo in the growing turkey ( Meleagris gallopavo) and chicken ( Gallus domesticus

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1995

Hepatic secretion of VLDL was compared in young turkeys and chickens (8 and 4 weeks of age, respe... more Hepatic secretion of VLDL was compared in young turkeys and chickens (8 and 4 weeks of age, respectively) and older birds (11 and 8 weeks of age, respectively) reared together under the same nutritional conditions. VLDL, VLDL-TG and total TG secretion rates were higher in chickens than in turkeys. The cholesteryl ester content of turkey VLDL was higher than that of chicken. Differences in the fatty acid composition of the VLDL lipids were observed between the species: the proportion of linoleic acid was greater in turkeys, whereas monounsaturated fatty acids were more abundant in chickens. These results are consistent with the hypothesis of a positive relationship between hepatic lipogenesis, deita-9desaturation, VLDL secretion and fattening in turkeys and chickens.

Research paper thumbnail of Influence of a high ambient temperature on stearoyl-CoA-desaturase activity in the growing pig

Comparative Biochemistry and Physiology B-biochemistry & Molecular Biology, 1999

An experiment was conducted to determine the influence of a high ambient temperature on the stear... more An experiment was conducted to determine the influence of a high ambient temperature on the stearoyl-CoA-desaturase activity and fatty acid composition of backfat, leaf fat, Longissimus dorsi muscle and liver, in the growing pig. Eighteen Large White X Landrace castrated pigs (20 kg body weight) were divided into three groups: I (31 degrees C, ad libitum), II (20 degrees C, pair-fed on the 31 degrees C group) and III (20 degrees C, ad libitum) until 35 kg body weight. At 20 degrees C, the level of feed intake had no effect on stearoyl-CoA-desaturase activity, whatever the tissue (groups II and III). At similar levels of feeding, (groups I and II), the stearoyl-CoA-desaturase activity was lower at 31 degrees C (P < 0.001) than at 20 degrees C, regardless of the tissue, with the exception of the hepatic stearoyl-CoA-desaturase activity, which was similar in all three groups. This reduction of the stearoyl-CoA-desaturase activity at 31 degrees C could be related to a decrease in the monounsaturated fatty acid percentage in all the tissues, in hot conditions. The present results show that changes in fatty acid composition caused by environmental temperature, in the pig, may be attributed at least in part to an alteration in the stearoyl-CoA-desaturase activity.