Brief Summary of Minutes of Annual Meeting

Accomplishments Washington State University (Dodson), Objectives 1,2,3,4,5,6,7,8,9,10. Cell physiology of mature adipocytes during a return to a state of proliferation-competency and evaluation of daughter progeny cells. Pig-derived mature adipocytes were isolated, purified and proliferative-competent progeny cells were allowed to undergo population expansion to insure cycling of all cells through the cell cycle. Progeny cells were then plated at equal numbers, in triplicate, and provided reduced levels of serum-containing media, without any differentiation-induction treatment (no DMI) and monitored for conversion to lipid-assimilating adipocytes. Cultures were terminated, RNA was preserved and is in the process of being evaluated for microRNA. Significance. Less than 30 microRNA species have been identified (to date) for the pig. This research will add to this number and help determine if microRNA plays any role in conversion of proliferative-competent cells into lipid-assimilating cells, in vitro. Results. In progress. Funding. This work is being completed in conjunction with researchers in Canada (Dr.'s LeLuo Guan, Weiwu Jin, Priya Mir, and Steve Moore), China (Dr. Jie Chen), the USA (Dr.'s Hausman, Poulos and Fernyhough) and at WSU (Dr. Zhihua Jiang). Collaborative Efforts:1. I am trying to make an effort to involve as many members of this group into the collective writing of data papers, review papers, opinion papers, and grants. In order to survive (in the future) these types of efforts will be demanded. I am willing to "spear-head" such efforts. 2. I am trying to become efficient at nominating individuals (of this group) for a variety of awards. Why? Many individuals of this group have already received numerous awards. This group will need such continued efforts in the future to demonstrate National/International prominence. University of California, Davis. (Sainz) Objectives. 1,2,3,4. Our group has continued work on two fronts: mathematical modeling of adipocyte hyperplasia and hypertrophy in beef cattle, and experimental analyses of the factors affecting these processes. The modeling work has benefited from collaboration with a group in Australia with access to a large dataset comprising several genetic groups and nutritional management strategies. Work is ongoing to fit our models to a subset of those data, and to use the remainder to challenge the models. Experimentally, we have been working on optimal protocols for sampling and analysis of bovine muscle for determination of adipocyte cellularity. Sampling bias is the major source of variation when estimating adipocyte size and number. A sampling technique should be developed to reduce sampling bias and increase the precision when estimating adipocyte cellularity. Currently our laboratory is developing such technique. Ohio State University (Lee), objectives 1,2,3,4,5,6,7,8,9,10. Enhancing growth rates with larger muscle mass, reduction of subcutaneous fat, and enhanced intramuscular fat will be beneficial to livestock producers and the consumer. We have focused on discovery of novel factors and understanding their roles in adipose tissue and muscle development. We have employed DNA microarray to discover new candidate genes for fat accretion in food-animals and human obesity. To further evaluate whether these genes are strong candidates for the obesity condition, we recently developed a series of experimental methods for a rapid high throughput screening. Using our unique approach, we have selected several candidate genes as a high priority group to intensively study the role of these candidate genes in adipocyte development and obesity. Adipose triglyceride lipase (ATGL), a newly discovered lipase, hydrolyzes the first ester bond of stored triglycerides which releases nonesterified-free fatty acids. However, the role of ATGL in fat accretion and development has not been studied in the avian species. Recently, we have cloned and sequenced the ATGL cDNAs for chickens, turkeys and quails. In 2009, we completed the study on the expression of the ATGL gene in adipose tissue during the developmental process, in response to hormonal stimuli and nutritional status. We are also working on the effect of overexpression of ATGL in adipose tissue on adipose development and lipid metabolism in transgenic birds. Currently, our collaborative team put a great effort on the grant proposal to integrate microarray, proteomic, bioinformatic and functional genomic analyses into an adipomic approach to understand the fundamentals of adipose tissue biology. Iowa State University (Beitz), objectives 1,2,3,5,6,9. High concentrations of saturated fatty acids (SFA) in human diets are known to increase plasma cholesterol concentrations and as a result, increase the risk of developing cardiovascular diseases, the number one cause of death worldwide. Separate SFA, however, do not have the same effect on plasma cholesterol concentrations. Palmitic (16:0) and myristic (14:0) acids, for example, can raise plasma cholesterol concentrations much higher than other SFA. Bovine milk is one of the primary sources of SFA in human diets and the concentration of palmitic (16:0) acid in milk is the highest compared with the other fatty acids. So, the main objective of our project was to develop genetic markers allowing for the selection of animals that can produce milk with healthier fatty acid profile. The candidate gene approach was used to address the objective. Genes involved in milk triacylglycerol (TAG) biosynthesis, fatty acid uptake into mammary gland and fatty acid transport inside the mammary epithelial cells, and transcriptional regulation of some lipogenic genes were selected for the study. DNA sequencing was used to discover single nucleotide polymorphisms (SNPs) in the genes of interest and after genotyping 550 cows for the discovered SNPs, haplotype reconstruction was performed to test the association of genetic polymorphisms with milk fatty acid composition. The phenotypic data were comprised of milk samples collected for each cow once a month throughout a 305 d lactation period with subsequent analysis of all the milk samples for fatty acid composition by using gas chromatography. The glycerol-3-phosphate acyltransferases-1 and -4 (GPAT1 and GPAT4), 1-acylglycerol-3-phosphate acyltransferase-1 (AGPAT1), and phosphatidate phosphatase (LPIN1) genes from the TAG biosynthetic pathway were studied to test the association of the polymorphisms in those genes with milk fatty acid composition. The polymorphisms in GPAT4 gene were significantly associated with the concentrations of capric (10:0), lauric (12:0), palmitic (16:0), oleic (18:1c9), and linoleic (18:2c9, c12) acids and as a consequence with the concentrations of SFA, unsaturated fatty acids (UFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), SFA/UFA ratio, C16 and C18 desaturation indices and atherogenic index (AI). As compared with the effects of diacylglycerol acyltransferase-1 (DGAT1) A232K mutation on milk fatty acid composition, the size of the effects of GPAT4 polymorphisms was bigger for AI, concentrations of SFA, UFA, MUFA, SFA/UFA ratio, concentrations of capric (10:0), lauric (12:0), linoleic (18:2c9, c12) acids, CLA (18:2c9, t11), and C18 desaturation index. The effects of GPAT1 polymorphisms were associated with the concentrations of caproic (6:0), caprylic (8:0), capric (10:0), tridecylic (13:0), margaric (17:0), myristoleic (14:1c9), palmitoleic (16:1c9) acids, C14 and C16 desaturation indices. The size of the effects of GPAT1 polymorphisms on the concentrations of caproic (6:0), caprylic (8:0), tridecylic (13:0), margaric (17:0) acids, and C14 and C16 desaturation indices was bigger compared with the size of the effects of DGAT1 A232K mutation. The polymorphisms in AGPAT1 gene were associated with PUFA, caproic (6:0), margaric (17:0), myristoleic (14:1c9) acids, and CLA (18:2c9, t11) concentrations. The polymorphisms in LPIN1 gene were associated with only myristoleic (14:1c9) acid concentration and C14 desaturation index.The isoform A6 of solute carrier family 27 (SLC27A6) and fatty acid binding proteins 3 and 4 (FABP3 and FABP4) genes involved in fatty acid uptake into mammary gland and fatty acid transport inside the mammary epithelial cells were studied to test the association of the polymorphisms in those genes with milk fatty acid composition. The concentrations of capric (10:0), lauric (12:0), myristic (14:0), and palmitic (16:0) acids in milk were significantly associated with the polymorphisms in SLC27A6 gene. The AI, concentrations of SFA, UFA, MUFA, and SFA/UFA ratio were affected by SLC27A6 genetic polymorphisms as well as a consequence of the association with medium-chain fatty acids and palmitic (16:0) acid. The size of the effects of the SLC27A6 genetic polymorphisms on the concentrations of MUFA, capric (10:0) and lauric (12:0) acids were bigger compared with the size of the effects caused by DGAT1 A232K mutation. The effects of SLC27A6 genetic polymorphisms on other traits such as AI, the concentrations of SFA, UFA, palmitoleic (16:1c9) acid, and the SFA/UFA ratio were very close in size to those observed for DGAT1 A232K mutation. The concentration of myristic (14:0) acid was affected by SLC27A6 polymorphisms to a greater extend compared with the effects of fatty acid synthase g. 17924 A>G mutation. The polymorphisms in FABP3 gene were associated with pentadecylic (15:0) and oleic (18:1c9) acid concentrations and the elongation index. The FABP4 genetic polymorphisms were associated with SFA, UFA, MUFA, PUFA, linoleic (18:2c9, c12) acid concentrations and SFA/UFA ratio.The sterol regulatory element binding protein-1c (SREBP-1c) is involved in the transcriptional regulation of lipogenesis and its proteolytic activation is controlled by SREBP cleavage-activating protein (SCAP) and insulin-induced genes (Insig) that are all part of so called the SREBP pathway. The effects of SREBP genetic polymorphisms were associated with the concentrations of myristic (14:0), myristoleic (14:1c9) acids, and C14 desaturation index. The effects of Insig-1 genetic polymorphisms were associated with the concentrations of MUFA, PUFA, yristoleic (14:1c9), palmitic (16:0), linoleic (18:2c9, c12) acids, and C16 desaturation index. There were no associations of SCAP genetic polymorphisms with milk fatty acid composition.In conclusion, we were able to identify genetic polymorphisms in GPAT4, GPAT1, and SLC27A6 genes that were associated with the differences in milk fatty acid composition and the size of those differences for certain fatty acids was the largest ever know even when compared with the effects of DGAT1 A232K mutation. The associations of the polymorphisms for the other genes were valuable as well. The results of this study provide the information about genetic polymorphisms that can be used to develop genetic markers for the selection of animals that will produce milk with the healthier fatty acid profile. North Carolina State University (Odle), objectives 1,2,3,8. Production of value-added pork by enrichment with omega-3 fatty acids.This study evaluated the impact of dietary docosahexaenoic acid (DHA) and linolenic acid (LN) on enrichment of n-3 fatty acids in pork when supplemented for the last 4 or 8 wk of the finisher period. Diets consisted of a corn-soybean meal based control supplemented with 0, 1.5 or 3.0% DHA-GOLD® (Martek Biosciences Corp, Columbia, MD) to supply 0, 0.27, or 0.54% DHA, respectively, or with 1.04% flax seed oil (Jedwards International, Quincy, MA) to supply 0.54% LN. Products were substituted for a saturated fat source (Fat Pack 100, Milk Specialties, Dundee, IL). Pigs (n=40, 67.7±1.1 kg BW) were housed individually and given ad libitum access to feed and water. Pigs were slaughtered at 115.6±5.4 kg BW and a 2.5 cm thick loin chop was collected from each pig. Chops were trimmed into retail cuts and subsequently ground to obtain a homogeneous sample. Fat was extracted and fatty acid concentrations were determined using gas-liquid chromatography. Fat supplements did not affect (P > 0.05) daily weight gain (0.90±0.15 kg), feed intake (2.77±0.65 kg) or gain:feed (0.36±0.06), but increased DHA accumulation linearly with diet concentration and with feeding duration (P < 0.05). Supplemental LN tended to increase (P = 0.08) loin LN at wk 8 only. We conclude that pork loin content of n-3 fatty acids can be markedly enriched in as little as four weeks of supplementation during the late finisher phase. Furthermore, DHA was enriched more efficiently than LN, and LN supplementation did not alter DHA, suggesting low elongation and/or desaturation. Docosahexaenoic acid does not increase insulin sensitivity in gilts.Dietary fish oil increased insulin sensitivity in several species including miniature pigs. Fish oil is rich in eicosapentaenoic acid (EPA, 20:5, n-3) and docosahexaenoic acid (DHA, 22:6, n-3). The objective was to measure insulin sensitivity in gilts consuming diets containing added DHA. Gilts were fed diets formulated to contain 0% DHA (Control, Cont; n=5) or 0.54% added DHA provided by DHAgold (Martek Biosciences Corp., Columbia, MD; n=7). Inclusion of DHAgold also provided 0.23% added docosapentaenoic acid (DPA, 22:5, n-6). Diets were fed for 6 wks before measurement of insulin sensitivity. Body weight at the time of sampling was 110.0 kg (SEM 7.3 kg) for gilts fed Cont and 111.4 kg (SEM = 6.0 kg) for gilts fed DHA. An i.v. glucose tolerance test (IVGTT; 1.25 g glucose/kg BW 0.75) and an i.v. insulin tolerance test (IVITT; 0.30 IU insulin/kg BW 0.75) were conducted on successive days. Blood samples were taken from indwelling jugular catheters at 30, 15, and 5 min before and 2.5, 5, 10, 15, 20, 30, 40, 50, 60, 75, and 90 min after infusion to measure concentrations of Gluc and Ins (IVGTT) or Gluc only (IVITT). Basal concentrations of Gluc and Ins did not differ between diets and were 5.06 and 4.82 mM Gluc; and 12.6 and 9.2 uIU/mL Ins for Cont gilts and DHA gilts, respectively. The area under the response curve (AUC) for Gluc response to the Gluc infusion (mM Gluc x 30 min) tended to be greater (P < 0.07) in gilts fed DHA (113.9) compared to Cont gilts (94.0). There was a tendency (P = 0.10) for greater Gluc half-life (min) in gilts fed DHA (9.96) than gilts fed Cont (8.52). The AUC for Ins response to the Gluc infusion and the AUC for Gluc response to the Ins infusion did not differ for the 2 groups and were 1002 and 1266 (uIU insulin/mL x 30 min) for Cont and DHA gilts, respectively, and 182 and 170 (mM Gluc x 90 min) for Cont and DHA gilts, respectively. Lack of response suggests that fish oil may not increase Ins sensitivity in these pigs, the response observed due to feeding fish oil is due to EPA rather than DHA, or the presence of DPA diminished the response. Purdue University (Ajuwon), objectives 1,2,3,4,6,8,10. Our research team has continued our work on the regulation of inflammation in adipose tissue. In 2009, we described the role of TLR2 in the adipocyte. Although adipocytes express multiple toll-like proteins, toll-like receptor 4 (TLR4) has been the most widely studied. However, obesity is accompanied by an increase in the expression of TLR2 as well, indicating that this receptor might be implicated in the metabolic impairments such as insulin resistance of the obese adipose tissue. Using a peptidoglycan model of TLR2 activation, we showed that adipocytes have a functional TLR2 signaling apparatus that when activated leads to the induction of inflammatory cytokines like interleukin 6 (IL-6) at the mRNA and protein levels. Another focus of our work is the role of extracellular matrix (ECM) proteins in adipose tissue expansion. We have determined that there is differential regulation of ECM proteins in adipose tissue; especially there are differences in the subcutaneous and the visceral depot. These differences are true in multiple species (mice, pigs and humans). We have also determined that adipocyte proliferation and apoptosis may be under the regulation of ECM proteins such as decorin and biglycan. In in vitro experiments these proteoglycans lead to induction of apoptosis in 3T3-L1 preadipocytes. Additionally, because inflammation is a major component of obesity, we examined the regulation of inflammation by biglycan. Biglycan led to a significant induction of IL-6 expression both in macrophages and adipocytes. The implication of these findings is that under conditions of adipose tissue expansion and increased expression of ECM proteins. Proteins such as biglycan and decorin may serve to limit adipose tissue expansion by inducing adipocyte apoptosis. Additionally, biglycan may contribute to the induction of inflammation that is observed in obesity. Although our work is mostly in adipose tissue, through collaboration with colleagues in the department of animal sciences at Purdue and elsewhere, we are studying the regulation of inflammation in the gastrointestinal tract as well with a view to establishing the link between gut inflammation and efficiency of animal growth which includes impact on adiposity. We have a few published abstracts in this area in 2009. Specifically, we have worked on the modulation of inflammation in the gastrointestinal tract by non-antibiotic products like yeast under conditions of mild immune stimulation with a coccidia vaccine. Texas A&M University (Smith), objectives 1,2,3,7. There is a growing interest in documenting the effect of diet on the ability to convert saturated fatty acids (SFA) to monounsaturated fatty acids (MUFA) by modulating expression of the stearoyl-CoA desaturase (SCD) gene. We proposed that if cattle were raised to a constant body weight, their MUFA:SFA ratio would be the same regardless of being calf-fed (CF) or yearling-fed (YF). Twenty-four Angus steers were slaughtered at weaning at 8 mo of age (n = 4), eight steers were assigned to the CF group and slaughtered at 12 mo of age (n = 4) or 16 mo of age (n = 4). Twelve steers were assigned to the YF group and slaughtered at 12 mo of age (n = 4), 16 mo of age (n = 4) and market weight (525 kg; n = 4). Data were analyzed statistically based on time on high-energy diet with terminal age as a covariate and orthogonal polynomial contrasts were tested on the main effects of group and time. Yield grades increased over time in all steers (P < 0.01), and YF steers had higher yield grades than CF steers (P = 0.05). Histological sections of the LM were also taken to visualize the intramuscular fat development, and indicated that both the number of lipid-filled cells and the size of the lipid-filled cells increased in the LM i.m. adipose tissue depots. The slip point temperatures of the s.c. adipose tissue lipids decreased for all groups as time on feed increased (P < 0.01). The concentration of cholesterol in the longissimus muscle tended to be less in YF steers than in CF steers (P = 0.06). A trained sensory panel detected no significant differences between palatability of flavor characteristics of cooked steaks from intermediate CF steers and terminal CF and YF steers (P > 0.05).Digesta linoleic acid (18:2n-6) increased with time on the corn based diet in both groups, whereas digesta a-linolenic acid (18:3n-3) decreased over time (P < 0.01). Similarly, plasma linoleic acid increased over time on the corn-based diet; the digesta and plasma increases in linoleic acid were consistent with the contribution of linoleic acid from the corn-based finishing diet. Plasma MUFA and a-linolenic acid decreased over time in the finishing diet, decreased, primarily in the CF group. The percentage of i.m. lipid from the longissimus muscle (LM) increased over time (P < 0.01), regardless of group. In s.c. adipose tissue, palmitoleic acid (16:1n-7) increased over time (P < 0.01), and oleic acid (18:1n-9) increased at a faster rate in CF than in YF steers (TxG, P = 0.05). Correspondingly, the s.c. adipose tissue MUFA:SFA ratio increased over time (P < 0.01) but was not different between groups (P = 0.26). The i.m. adipose tissue MUFA:SFA ratio was higher in CF than in YF steers (P = 0.04). There was a quadratic response in s.c. adipose tissue SCD gene expression over time (P < 0.01), in that gene expression declined after 4 mo on the finishing diet in both the CF and YF steers (Figure 1). In i.m. adipose tissue, SCD gene expression declined in CF steers between 12 and 16 mo of age, but did not change in YF steers. This coincided with a slowing of the rate of accumulation of marbling in the CF steers, and a gradual increase in marbling in YF steers. We conclude that corn feeding increases marbling development and i.m. adipose tissue SCD gene expression, which was not achieved in the YF steers of this study. USDA ARS, Athens (Hausman), objectives 1,2,3,4,5,6,7,8,9,10. In this study, total RNA was collected from abdominal adipose tissue samples obtained from ten broiler chickens at 3, 4, 5, and 6 weeks of age and prepared for real time RT-PCR analysis. Studies of the gene expression of cytokines and associated genes in chicken adipose tissue were initiated since it has been shown in many animal species that adipose tissue derived factors can dramatically influence growth and physiology. The influence of age on the expression of adipose tissue IL-15, IL-8, neuropeptide Y and GHR and LPR genes and several other cytokines was examined. Between 3 and 6 weeks of age LPR expression decreased (P < 0.05) with age while expression of IL-15 and GHR increased significantly (P < 0.05). Furthermore, IL-8 and visfatin expression increased (P < 0.001) between 4 and 6 weeks of age. This is the first demonstration of age related changes in cytokine gene expression in chicken adipose tissue. Gene expression of several cytokines was not detected in chicken adipose tissue including IL-6 and brain derived neurotrophic factor. Future studies are needed to elucidate the role of adipose tissue cytokines in growth and, possibly, disease resistance. USDA ARS, Davis (Adams), objectives 1,2,4,5,6. Our laboratory focuses on the biology of adipose tissue, with the ultimate goal of applying this knowledge toward strategies to improve public health via nutritional and physical activity interventions. One aspect that is important to adipose tissue function and ultimately, whole-body insulin sensitivity, is inflammation, since low-grade inflammation in white adipose tissue (WAT) is often associated with obesity and this plays a role in insulin resistance. Such inflammation might be impacted by nutrition (at least in monogastrics), i.e., via increasing intakes of anti-inflammatory phytonutrients, limiting dietary saturated fat intake, limiting calories and hence excess body fat. Dietary calcium has been hypothesized to reduce WAT inflammation, but strong evidence for this from multiple laboratories is lacking. Epidemiological studies and research in animal models support an inverse relationship between dietary Ca and dairy food consumption with adiposity. Proposed mechanisms of adiposity reduction by dairy include decreased digestibility of fats due to formation of indigestible Ca soaps and dietary Ca suppression of calcitriol that alters energy metabolism and thermogenesis. Bioactive components from dairy protein are thought to have additional synergistic effects. We compared the effects of a high Ca (HC) diet vs. HC with nonfat dry milk (NFDM) on obesity phenotypes, including adipose tissue inflammation. Adult male C57BL/6J mice fed an obesigenic, pro-inflammatory high fat diet (45% kcal; HF) were assigned (n=30/group) to one of three macronutrient-matched HF diets for 12 wks: control (0.5% Ca; CON), HC (1.5% Ca), or HC with NFDM. Surprisingly, body weight and fat were increased ~18% and ~19% in HC mice vs. CON (P<0.001); these parameters decreased ~13% and ~43% in NFDM mice (P<0.001). Feed efficiency was significantly increased ~10% in HC mice and reduced ~33% in NFDM mice vs. CON. NFDM mice had improved glucose tolerance compared to both CON (P<0.01) and HC mice (P<0.001). Markers of adipose inflammation track the obesity and glucose homeostasis phenotypes (i.e., significantly increased in obesity, lowered by NFDM). We conclude that anti-obesity effects of dairy foods are not mediated by increased dietary Ca in high fat fed mice, and that inflammation and obesity phenotypes are not negatively correlated with calcitriol levels in the blood. Washington State University (Dodson), objectives 1,3,4,7. During 2008/2009 we have devised methods to isolate and quantitatively evaluate the dedifferentiation of individual mature (lipid-laden) adipocytes from pig-derived (subcutaneous and intramuscular) adipose tissues. We have determined that pig-derived adipocytes must extrude substantial lipid from the cell prior to becoming proliferative-competent. This single observation (of the need to physically rid itself of a majority of cytosolic lipid) is different to what we had previously observed in similar beef cow adipocyte cultures. Significance. We have been criticized that this process may never occur in vivo. Whether it does or doesn't remains to be seen. Instead, this system may be used to identify regulators of the dedifferentiation process, which might (in the future) be exploited for in vivo work. This system (as we have devised it) is novel and our goals are quite simple: to determine the regulation of the potential for adipocytes to either expand their presence in adipose tissue, or to transdifferentiate into other types of cells. In fact, as these cells possess ability to re-proliferate, they may not be traditional adipocytes (as most traditional biologists may have once thought). We are keeping an open mind. Results to support our research. Progeny cells (from beef cows) do NOT express the same gene profile (during a process to re-induce differentiation) as do primary preadipocytes or SV cells (papers published). This work is done in conjunction with researchers in Canada and in China, and is presently funded by a small grant from the University of Alberta. West Virginia University (Barnes), objectives 1,2,10. The primary goal of our laboratory is to understand the mechanism(s) of action of dietary conjugated linoleic acid-induced body fat loss. We have utilized a model of enhanced CLA responsiveness in mice raised from weaning, for 6 weeks prior to CLA supplementation, on diets deficient in polyunsaturated fatty acids (coconut oil or fat free). This year we have also investigated the effect of CLA on feed intake and pork marbling. As well, we have investigated the effect of different sources of DHA on body composition and serum lipids. Use of a mouse model for conjugated linoleic acid-induced changes in adipose depots. Dietary conjugated linoleic acid (CLA) has been reported to decrease backfat and increase marbling in pigs. The objective of this study was to determine the effect of CLA on lipid accumulation in mouse muscle. Male mice (n=80) were fed 7% soy oil (SO) or coconut oil (CO) diets for 6 wk, then 0 or 0.5% CLA was added for 12 d. A body fat index was calculated and muscle lipid content was determined by ether extraction. Fatty acid ² -oxidation was indicated by determining the enzyme activity of carnitine palmitoyl-transferase (CPT)-1. Body fat was reduced by CLA (P < 0.05). CLA caused a 28% decrease (P < 0.01) in thigh muscle lipid and a non-significant (P = 0.22) 24% decrease in back muscle lipid. CPT-1 activity in thigh muscle was decreased by CLA (P < 0.01) in SO-fed mice (80.94 vs. 14.27 EU/ mg protein) but not in CO-fed mice (38.86 vs. 12.49 EU/ mg protein). University of Wyoming (Du, Rule), objectives 1,2,3,4,5,6,7,8,9,10. The interrelationship between diet, fetal growth and muscle and fat development are currently the focus of research at the University of Wyoming, Department of Animal Science relating to regulation of adipose tissue growth in meat animals, the focus of NCCC-021. Min Dus research addresses regulation of fetal muscle and adipose tissue development with AMPK as the focal point of this regulation. Dan Rules research has emphasized how diet, in particular grass fed beef, affects the lipid composition of muscle and adipose tissue of beef cattle. This years station report from the University of Wyoming will address these two areas. AMPK in regulation of fetal tissue development (Dr. Min Du). Fetal skeletal muscle development associated with myogenesis, adipogenesis and fibrogenesis from mesenchymal stem cells. We have continued to our effort to define the role of AMP-activated protein kinase (AMPK) in mesenchymal stem cell differentiation and fetal skeletal muscle development. Our studies show that AMPK activity is negatively associated with adipogenesis and fibrogenesis, but positively correlated with myogenesis. We also found that AMPK regulates mesenchymal stem cell differentiation through phosphorylating ²-catenin at Ser 552 which improves the stability and transcriptional activity of ²-catenin. Inhibition of AMPK enhanced adipogenesis. The Wnt/ ²-catenin signaling pathway is known to enhance myogenesis but inhibits adipogenesis. Auburn University (Bergen). We have continued to screen mRNA abundance in skeletal muscles and subcutaneous adipose tissues of key target genes involved with lipid accretion (PPAR³, fatty acid synthase, SREBP-1c, SCD), fat catabolism and the role of uncoupling proteins (PPAR±, Acyl CoA dehydrogenase,-beta oxidation, UCP) and protein metabolism (key genes in the proteasomal pathway) in cattle under varying production systems in the Southeast. Our current set of samples are from a heifer finishing study with a single 30 day Optaflexx supplementation starting at 300kg at 50 kg increments to 500 kg. . The results are still incomplete and will be available next year. Other efforts are to garner preliminary data for the new USDA/AFRI priorities in animal agriculture competitive grants program. We are mostly focused on adipocyte biology in vivo as related to climate change and high/low ambient temperatures.