We hypothesized that carcass and fatty acid composition of Angus and Japanese Black (Wagyu) steers would not differ if the steers were fed to a typical U.S. final weight, but that Wagyu steers fed to a typical Japanese endpoint body weight would have greater quality grades and softer fat than Angus steers. Sixteen Angus and 16 Wagyu 8-month-old, weaned steers were assigned to a corn-based diet for 8 or 16 months (n = 4 per breed type and time) or hay-based diet for 12 or 20 months (n = 4 per breed type and time) in a 2 x 2 x 2 factorial arrangement. USDA yield grade was greater at the Japanese endpoint than at the U.S. endpoint in Angus steers (breed x endpoint, P = 0.03). Intramuscular (i.m.) lipid continued to increase to over 20% in the Wagyu steers (P = 0.05), but attained a plateau (14.7%) by 16 months on feed in the Angus steers. These results confirm that Wagyu cattle must be raised to greater physiological maturity before they differ from Angus cattle in M. longissimus thoracis i.m. lipid concentration. Subcutaneous adipose tissue concentrations of oleic (18:1n-9) was greater in Wagyu steers than in Angus steers (P = 0.05). All monounsaturated fatty acids (MUFA) increased between the U.S. and Japanese endpoint, whereas slip points of lipids in s.c. adipose tissue were 10°C lower in Japanese endpoint steers than in U.S. endpoint steers (P = 0.01). Angus adipose tissue exhibited peak SCD enzyme activity at 16 months (corn-based diet) but activity in Wagyu adipose tissue was greatest at 20 months (hay-based diet) (breed x diet x endpoint, P = 0.08). However, SCD gene expression in Angus adipose tissue was maximal at 12 months (hay diet), whereas Wagyu adipose tissue had peak expression at 16 months (corn diet) (P < 0.03). Trans-10, cis-12 CLA has been reported as a potent inhibitor of adipocyte differentiation. CLA (40 µM) strongly decreased SCD and PPARγ expression in bovine adipocytes, even in the presence of 5 mM arginine. It can be concluded that arginine up-regulates bovine preadipocyte differentiation, and CLA antagonizes this effect.

Fifteen steers were used to evaluate the difference of diets (corn-based for 8 mo or hay-based for 12 mo) and breeds (Angus; n = 7 or Wagyu; n = 8) in a completely randomized design with 2 x 2 factorial arrangement of treatments to test the hypothesis that there are differences in fatty acid metabolism and cellularity in subcutaneous (s.c.) and intramuscular (i.m.) adipose tissue between these breeds types. Fat thickness, carcass weight, overall maturity, and yield grade of Angus steers were higher than those of Wagyu steers fed either corn (34%, 22%, 3%, and 8% higher, respectively) or hay diets (20%, 8%, 10%, and 8% higher, respectively) (P < 0.03). Moreover, marbling scores tended (P = 0.70) to be greater in Angus steers than in Wagyu steers fed either diet. Lipogenesis from acetate in both s.c and i.m. adipose tissue was higher in Wagyu steers (212.82 and 86.23 nmol/(105 cells per 2 h)) than in the Angus steers (86.23 and 29.66 nmol/(105 cells per 2 h)). Also, acetate incorporation into fatty acids was greater in s.c. adipose tissue than in i.m. adipose tissue (P < 0.05). Subcutaneous adipose tissue stearoyl-CoA desaturase (SCD) activity was significantly greater in corn-fed steers and than in hay-fed steers (P < 0.05), but there was no difference in SCD activity between Angus and Wagyu steers (P > 0.05). Adipocyte cellularity data demonstrated that both breeds have more cells per gram adipose tissue and smaller cell volumes in i.m. adipose tissue than in s.c. adipose tissue. In s.c. adipose tissue, saturated fatty acids tended to be lower in corn-fed Angus and Wagyu steers than in hay-fed steers (P < 0.06). Similarly, monounsaturated fatty acids were higher in corn-fed Wagyu and Angus steers than in hay-fed Wagyu and Angus steers (P < 0.01). Slip point was positively correlated with percentage stearic acid in corn-fed and hay-fed steers, and there was a negative correlation between slip point and the SCD index. These data demonstrated that corn-based diets provide not only increased contents of monounsaturated fatty acid in Angus and Wagyu adipose tissue but also increased lipogenic activity.

Fifteen steers were used to evaluate the difference of diets (corn-based for 8 mo or hay-based for 12 mo) and breeds (Angus; n = 7 or Wagyu; n = 8) in a completely randomized design with 2 x 2 factorial arrangement of treatments to test the hypothesis that there are differences in fatty acid metabolism and cellularity in subcutaneous (s.c.) and intramuscular (i.m.) adipose tissue between these breeds types. Fat thickness, carcass weight, overall maturity, and yield grade of Angus steers were higher than those of Wagyu steers fed either corn (34%, 22%, 3%, and 8% higher, respectively) or hay diets (20%, 8%, 10%, and 8% higher, respectively) (P < 0.03). Moreover, marbling scores tended (P = 0.70) to be greater in Angus steers than in Wagyu steers fed either diet. Lipogenesis from acetate in both s.c and i.m. adipose tissue was higher in Wagyu steers (212.82 and 86.23 nmol/(105 cells per 2 h)) than in the Angus steers (86.23 and 29.66 nmol/(105 cells per 2 h)). Also, acetate incorporation into fatty acids was greater in s.c. adipose tissue than in i.m. adipose tissue (P < 0.05). Subcutaneous adipose tissue stearoyl-CoA desaturase (SCD) activity was significantly greater in corn-fed steers and than in hay-fed steers (P < 0.05), but there was no difference in SCD activity between Angus and Wagyu steers (P > 0.05). Adipocyte cellularity data demonstrated that both breeds have more cells per gram adipose tissue and smaller cell volumes in i.m. adipose tissue than in s.c. adipose tissue. In s.c. adipose tissue, saturated fatty acids tended to be lower in corn-fed Angus and Wagyu steers than in hay-fed steers (P < 0.06). Similarly, monounsaturated fatty acids were higher in corn-fed Wagyu and Angus steers than in hay-fed Wagyu and Angus steers (P < 0.01). Slip point was positively correlated with percentage stearic acid in corn-fed and hay-fed steers, and there was a negative correlation between slip point and the SCD index. These data demonstrated that corn-based diets provide not only increased contents of monounsaturated fatty acid in Angus and Wagyu adipose tissue but also increased lipogenic activity.

We hypothesized that carcass and fatty acid composition of Angus and Japanese Black (Wagyu) steers would not differ if the steers were fed to a typical U.S. final weight, but that Wagyu steers fed to a typical Japanese endpoint body weight would have greater quality grades and softer fat than Angus steers. Sixteen Angus and 16 Wagyu 8-month-old, weaned steers were assigned to a corn-based diet for 8 or 16 months (n = 4 per breed type and time) or hay-based diet for 12 or 20 months (n = 4 per breed type and time) in a 2 x 2 x 2 factorial arrangement. USDA yield grade was greater at the Japanese endpoint than at the U.S. endpoint in Angus steers (breed x endpoint, P = 0.03). Intramuscular (i.m.) lipid continued to increase to over 20% in the Wagyu steers (P = 0.05), but attained a plateau (14.7%) by 16 months on feed in the Angus steers. These results confirm that Wagyu cattle must be raised to greater physiological maturity before they differ from Angus cattle in M. longissimus thoracis i.m. lipid concentration. Subcutaneous adipose tissue concentrations of oleic (18:1n-9) was greater in Wagyu steers than in Angus steers (P = 0.05). All monounsaturated fatty acids (MUFA) increased between the U.S. and Japanese endpoint, whereas slip points of lipids in s.c. adipose tissue were 10°C lower in Japanese endpoint steers than in U.S. endpoint steers (P = 0.01). Angus adipose tissue exhibited peak SCD enzyme activity at 16 months (corn-based diet) but activity in Wagyu adipose tissue was greatest at 20 months (hay-based diet) (breed x diet x endpoint, P = 0.08). However, SCD gene expression in Angus adipose tissue was maximal at 12 months (hay diet), whereas Wagyu adipose tissue had peak expression at 16 months (corn diet) (P < 0.03). Trans-10, cis-12 CLA has been reported as a potent inhibitor of adipocyte differentiation. CLA (40 µM) strongly decreased SCD and PPAR&#947; expression in bovine adipocytes, even in the presence of 5 mM arginine. It can be concluded that arginine up-regulates bovine preadipocyte differentiation, and CLA antagonizes this effect.

No description available.

The effects of diet on milk fatty acid profile, including conjugated linoleic acid (CLA) have been well documented, however, there is limited information on the interaction of diet with genetics. The objective of this research was to determine the effect of single nucleotide polymorphisms (SNP) in the stearoyl CoA desaturase (SCD) gene on the ability to produce CLA in dairy cows fed low and high fat diets. The secondary objective was to determine the effect of a SNP in fatty acid synthase (FASN) on milk yield and composition. There was no effect of SCD genotype on CLA concentration, however there was an effect of SCD genotype on the ratio of C14:1/C14:0 which tended to be associated with CLA concentration when animals were fed a high fat diet. The FASN genotype affected milk yield, while composition remained constant. / Animal Science

A produção in vitro (PIV) de embriões tem sido utilizada amplamente no Brasil como ferramenta para acelerar o melhoramento genético do rebanho. Quando associada à criopreservação, a PIV permite maior flexibilidade da biotecnologia e possibilita estabelecer um banco de embriões. Há a possibilidade que a alta sensibilidade à criopreservação dos embriões bovinos seja influenciada principalmente pela grande quantidade de lipídeos intracitoplasmáticos, sendo isso relacionado especialmente às condições de cultivo in vitro. O Etossulfato de Fenazina (PES) consiste em um regulador do metabolismo de lipídeos. Através da oxidação de NADPH, estimula a via da pentose-fosfato e assim inibe a síntese de ácidos graxos, podendo levar a efeitos benéficos na criopreservação de embriões bovinos produzidos in vitro. O Fator de transcrição denominado proteína de ligação do elemento regulatório de esterol (SREBP-1c), regula preferencialmente a transcrição de genes da síntese de triacilglicerol e fosfolipídios e, a enzima Estearoil Co-A desaturase (SCD1) promove a síntese de ácidos graxos monoinsaturados, conferindo fluidez às membranas celulares. O objetivo desse trabalho foi avaliar a suplementação de diferentes concentrações do etossulfato de fenazina (PES) no meio de cultivo, durante a produção in vitro de embriões bovinos, e verificar o efeito do PES na taxa de gestação, buscando melhorar a qualidade do embrião para a criopreservação através da redução do acúmulo de lipídeos. Foram avaliadas as taxas de desenvolvimento inicial de embriões produzidos in vitro provenientes de ovários de abatedouro, e as taxas de gestação com o uso de embriões bovinos produzidos in vitro a partir da Aspiração folicular de vacas Holandesas e vitrificados. A análise da expressão de genes relacionados com biossíntese de triacilglicerol, SCD1 e SREBP-1c, teve como finalidade auxiliar nos conhecimentos básicos dos mecanismos de ação do Etossulfato de Fenazina, e foi realizada através de PCR quantitativo em Tempo Real, utilizando pools de cinco embriões para cada grupo. Para a análise estatística, foi realizada ANOVA seguida de teste de médias, e o teste qui-quadrado para as taxas de gestação. Não houve diferença estatística na taxa de clivagem e blastocisto entre o grupo controle e os grupos tratados com 0,2µM; 0,3µM; 0,5µM de PES no meio de cultivo in vitro. A taxa de gestação, utilizando-se embriões criopreservados, transferidos para receptoras, não foi alterada pelo uso de PES. A expressão tanto do SREBP-1c, quanto da SCD1 manteve níveis similares na presença ou ausência de PES durante o cultivo in vitro. Sendo assim faz-se necessário novos estudos para investigar mais detalhadamente o mecanismo de ação do PES nos genes da via de biossíntese de lipídeos e se é viável sua utilização a campo. / The in vitro production (IVP) of embryos has been widely used in Brazil as a tool to accelerate the genetic breeding. When combined with cryopreservation, the IVP allows greater flexibility of biotechnology and enable to establish a bank of embryos. There is a possibility that the greater sensitivity to cryopreservation of bovine embryos is influenced mainly by the large amount of intracytoplasmic lipids, and that is especially related to in vitro culture conditions. The phenazine ethosulfate (PES) consists of a lipid metabolism regulator. By NADPH oxidation, stimulates the pentose-phosphate pathway and thus inhibits the fatty acids synthesis, leading to beneficial effects on cryopreservation of bovine embryos in vitro produced. The transcription factor called sterol regulatory element binding proteins (SREBP-1c), preferably regulates the gene transcription of phospholipids and triacylglycerol synthesis and the stearoyl-Co A desaturase (SCD1) enzyme promotes the monounsaturated fatty acids synthesis, giving fluidity to cell membranes. The aim of this study was to evaluate the supplementation of different concentrations of phenazine ethosulfate (PES) in the culture medium during in vitro production of bovine embryos, and determine the effect of PES in the pregnancy rate, aiming to improve the the embryo quality to cryopreservation by reducing the lipids accumulation. We evaluated the early development rates of in vitro produced embryos and pregnancy rates after inovulation of vitrified in vitro produced embryos derived from the Ovum Pick Up of Holstein cows. Expression analysis of triacylglycerol biosynthesis related genes, SCD1 and SREBP-1c, had the purpose to increase the basic knowledge on phenazine ethosulfate mechanisms of action, and was performed by Quantitative Real-Time PCR using pools of five embryos for each group. For statistical analysis, was performed ANOVA followed by mean test, and the chi-square test for pregnancy rates. There was no statistical difference in the cleavage rate and blastocyst rate between the control group and the groups treated with 0,2µM; 0,3µM; 0,5µM of PES in the medium in vitro culture. The pregnancy rate, using cryopreserved embryos transferred to recipient was not altered by the use of PES. The expression of the SREBP-1c as well as SCD1 remained similar in the presence or absence of the PES during in vitro cultivation. Therefore it is necessary further studies to investigate in more details the PES mechanism of action in the genes of lipid biosynthesis pathway and whether it is feasible to use the field.

A produção in vitro (PIV) de embriões tem sido utilizada amplamente no Brasil como ferramenta para acelerar o melhoramento genético do rebanho. Quando associada à criopreservação, a PIV permite maior flexibilidade da biotecnologia e possibilita estabelecer um banco de embriões. Há a possibilidade que a alta sensibilidade à criopreservação dos embriões bovinos seja influenciada principalmente pela grande quantidade de lipídeos intracitoplasmáticos, sendo isso relacionado especialmente às condições de cultivo in vitro. O Etossulfato de Fenazina (PES) consiste em um regulador do metabolismo de lipídeos. Através da oxidação de NADPH, estimula a via da pentose-fosfato e assim inibe a síntese de ácidos graxos, podendo levar a efeitos benéficos na criopreservação de embriões bovinos produzidos in vitro. O Fator de transcrição denominado proteína de ligação do elemento regulatório de esterol (SREBP-1c), regula preferencialmente a transcrição de genes da síntese de triacilglicerol e fosfolipídios e, a enzima Estearoil Co-A desaturase (SCD1) promove a síntese de ácidos graxos monoinsaturados, conferindo fluidez às membranas celulares. O objetivo desse trabalho foi avaliar a suplementação de diferentes concentrações do etossulfato de fenazina (PES) no meio de cultivo, durante a produção in vitro de embriões bovinos, e verificar o efeito do PES na taxa de gestação, buscando melhorar a qualidade do embrião para a criopreservação através da redução do acúmulo de lipídeos. Foram avaliadas as taxas de desenvolvimento inicial de embriões produzidos in vitro provenientes de ovários de abatedouro, e as taxas de gestação com o uso de embriões bovinos produzidos in vitro a partir da Aspiração folicular de vacas Holandesas e vitrificados. A análise da expressão de genes relacionados com biossíntese de triacilglicerol, SCD1 e SREBP-1c, teve como finalidade auxiliar nos conhecimentos básicos dos mecanismos de ação do Etossulfato de Fenazina, e foi realizada através de PCR quantitativo em Tempo Real, utilizando pools de cinco embriões para cada grupo. Para a análise estatística, foi realizada ANOVA seguida de teste de médias, e o teste qui-quadrado para as taxas de gestação. Não houve diferença estatística na taxa de clivagem e blastocisto entre o grupo controle e os grupos tratados com 0,2µM; 0,3µM; 0,5µM de PES no meio de cultivo in vitro. A taxa de gestação, utilizando-se embriões criopreservados, transferidos para receptoras, não foi alterada pelo uso de PES. A expressão tanto do SREBP-1c, quanto da SCD1 manteve níveis similares na presença ou ausência de PES durante o cultivo in vitro. Sendo assim faz-se necessário novos estudos para investigar mais detalhadamente o mecanismo de ação do PES nos genes da via de biossíntese de lipídeos e se é viável sua utilização a campo. / The in vitro production (IVP) of embryos has been widely used in Brazil as a tool to accelerate the genetic breeding. When combined with cryopreservation, the IVP allows greater flexibility of biotechnology and enable to establish a bank of embryos. There is a possibility that the greater sensitivity to cryopreservation of bovine embryos is influenced mainly by the large amount of intracytoplasmic lipids, and that is especially related to in vitro culture conditions. The phenazine ethosulfate (PES) consists of a lipid metabolism regulator. By NADPH oxidation, stimulates the pentose-phosphate pathway and thus inhibits the fatty acids synthesis, leading to beneficial effects on cryopreservation of bovine embryos in vitro produced. The transcription factor called sterol regulatory element binding proteins (SREBP-1c), preferably regulates the gene transcription of phospholipids and triacylglycerol synthesis and the stearoyl-Co A desaturase (SCD1) enzyme promotes the monounsaturated fatty acids synthesis, giving fluidity to cell membranes. The aim of this study was to evaluate the supplementation of different concentrations of phenazine ethosulfate (PES) in the culture medium during in vitro production of bovine embryos, and determine the effect of PES in the pregnancy rate, aiming to improve the the embryo quality to cryopreservation by reducing the lipids accumulation. We evaluated the early development rates of in vitro produced embryos and pregnancy rates after inovulation of vitrified in vitro produced embryos derived from the Ovum Pick Up of Holstein cows. Expression analysis of triacylglycerol biosynthesis related genes, SCD1 and SREBP-1c, had the purpose to increase the basic knowledge on phenazine ethosulfate mechanisms of action, and was performed by Quantitative Real-Time PCR using pools of five embryos for each group. For statistical analysis, was performed ANOVA followed by mean test, and the chi-square test for pregnancy rates. There was no statistical difference in the cleavage rate and blastocyst rate between the control group and the groups treated with 0,2µM; 0,3µM; 0,5µM of PES in the medium in vitro culture. The pregnancy rate, using cryopreserved embryos transferred to recipient was not altered by the use of PES. The expression of the SREBP-1c as well as SCD1 remained similar in the presence or absence of the PES during in vitro cultivation. Therefore it is necessary further studies to investigate in more details the PES mechanism of action in the genes of lipid biosynthesis pathway and whether it is feasible to use the field.

<p>Obesity is today a problem that has reached epidemic proportions. One of the causes of obesity is the over-consumption of energy. Fat is the most energy-dense nutrient, where the quality seems to be more important for the development of the metabolic diseases than the quantity. The fatty acid composition in serum lipid fractions can be used to mirror the dietary fat quality.</p><p>Stearoyl-CoA-desaturase (SCD) is an enzyme that converts saturated to monounsaturated fatty acids. A surrogate measure of SCD activity can be estimated as a fatty acid ratio; 16:1/16:0 (palmitoleic acid/palmitic acid) and 18:1/18:0 (oleic acid/stearic acid). The aim of this project was to investigate the intra-day variation in the SCD-ratio in humans eating a standardized diet. The results showed that triacylglycerol and nonesterified fatty acid fractions in serum lipids had a significant variance in the 16:1/16:0 ratio during the day, whereas 18:1/18:0 ratio in the same fractions did not exhibit the same pattern. In this study 16:1/16:0 ratio also seems to be a better marker than 18:1/18:0 ratio for estimating SCD activity. For further evaluation of the intra-day variation there need to be a more long-term study of the SCD-activity for a larger group of subjects.</p>

Obesity is today a problem that has reached epidemic proportions. One of the causes of obesity is the over-consumption of energy. Fat is the most energy-dense nutrient, where the quality seems to be more important for the development of the metabolic diseases than the quantity. The fatty acid composition in serum lipid fractions can be used to mirror the dietary fat quality. Stearoyl-CoA-desaturase (SCD) is an enzyme that converts saturated to monounsaturated fatty acids. A surrogate measure of SCD activity can be estimated as a fatty acid ratio; 16:1/16:0 (palmitoleic acid/palmitic acid) and 18:1/18:0 (oleic acid/stearic acid). The aim of this project was to investigate the intra-day variation in the SCD-ratio in humans eating a standardized diet. The results showed that triacylglycerol and nonesterified fatty acid fractions in serum lipids had a significant variance in the 16:1/16:0 ratio during the day, whereas 18:1/18:0 ratio in the same fractions did not exhibit the same pattern. In this study 16:1/16:0 ratio also seems to be a better marker than 18:1/18:0 ratio for estimating SCD activity. For further evaluation of the intra-day variation there need to be a more long-term study of the SCD-activity for a larger group of subjects.