Search

The importance of dietary fat components, such as fatty acids, in the expression of multiple genes is clear. In the case of beef cattle, fat in the form of fatty acids (saturated or unsaturated), vitamin A (mainly retinoic acid), or carotenoids ([beta]-carotene and lutein) is obtained from dietary feed or pasture. The aim of this work was to study the effect of fatty acids (phytanic and pristanic acids), vitamin A (all-trans and 9-cis retinoic acid), and carotenoids ([beta]-carotene and lutein) on the expression of PPAR[gamma] and its coactivator PGC-l[alpha] during differentiation of bovine white adipose tissue. Samples were collected at slaughter from subcutaneous adipose tissue and processed in a solution containing type II collagenase for 2 h at 37[degrees]C. Cells were resuspended in basal medium, Dulbecco's modified Eagle's medium containing 5% fetal bovine serum, plated on 24-well culture plates at a density of 1 x [10.sup.4] cells/ [cm.sup.2], and incubated at 37[degrees]C in a 5% C[O.sub.2] atmosphere. Preadipocyte differentiation after reaching confluence was induced by various treatments: rosiglitazone (20 [micro]M); unsaturated fatty acids: phytanic acid (25, 50, 100 [micro]M) and pristanic acid (25, 50, 100 [micro]M); retinoids: 9-cis retinoic acid (0.5, 0.75, 1 [micro]M) and all-trans retinoic acid (0.5, 0.75, 1 [micro]M); and carotenoids: [beta]-carotene (10, 20, 30 [micro]M) and lutein (10, 20, 30 [micro]M). Expression of PPAR[gamma] and PGC-1[alpha] was measured in differentiated cells. Phytanic acid, all-trans retinoic acid, and 9-cis retinoic acid were the best activators of PPAR[gamma] expression, and the combination of 9-cis and all-trans retinoic acid was the best activator of PGC-l[alpha] expression (P < 0.05). Therefore, these are powerful agents for the promotion of bovine adipogenesis and constitute promising compounds to be used in bovine fattening. Key words: beef cattle, dietary fat, peroxisomal proliferator-activated receptor [gamma], peroxisomal proliferatoractivated receptor [gamma] coactivator 1 doi: 10.2527/jas.2009-2579

The possibility that maternal diets during gestation could affect growth and tissue development of offspring and program their later phenotype is an emerging challenge in pig production. The objective of the current study was to investigate the effects of contrasted protein levels in diets of pregnant sows on the proteomic features of subcutaneous adipose tissue (SCAT) of the offspring at birth and its possible persistence later in age. Sows were fed control (Con), low (LP), or high protein (HP) diets throughout gestation. A subset of piglets was killed at 1 d of age for SCAT sampling. The remaining piglets were cross-fostered to nonexperimental sows during lactation. They were fed standard diets during postweaning and fattening periods until 186 d of age. Modifications in SCAT protein abundance shortly after birth were investigated by 2-dimensional gel electrophoresis followed by mass spectrometry. A total of 65 spots were found differentially expressed (P [less than or equal to] 0.10) in SCAT of l-d-old experimental piglets vs. Con piglets. Proteins with a greater abundance in LP piglets compared with Con piglets were involved in pathways related to glucose and fatty acid metabolisms, lipid transport, and regulation of apoptosis. Upregulation of 5 proteins representative of these biological pathways in LP group vs. Con group were further validated (P < 0.05) by Western blot analyses. Furthermore, the specific activity of the key lipogenic enzyme fatty acid synthase was found greater (P = 0.06) in SCAT of 1-d-old LP piglets than in Con piglets. The main changes evidenced in SCAT of HP piglets compared with Con animals at 1 d of age rather concerned proteins putatively involved in AA metabolism or in protein turnover. Adipose tissue contents in some proteins that had displayed a greater (P [less than or equal to] 0.10) abundance in experimental pigs compared with Con at d 1 (e.g., transaldolase, annexin II, and apolipoprotein A4) were, however, similar (P > 0.10) in the 3 groups at d 186 of age. Enolase 1 has less abundance (P < 0.05) in LP pigs compared with Con pigs at this stage. In conclusion, the proteomics tool has allowed the identification of early changes in various molecular pathways of SCAT in response to the levels of maternal protein supply during gestation. Key words: adipose tissue, annexin, glycolytic pathway, pig, prenatal diet, proteome doi: 10.2527/jas.2009-2542

Angiopoietin-like protein 4 (ANGPTL4; also known as fasting-induced adipose factor) is a plasma protein that stimulates oxidation of fatty acids and inhibits fat accumulation. The gastrointestinal tract appears to play an important role in regulating plasma ANGPTL4 concentration in some situations and may be influenced by microbes within the gastrointestinal tract. Our aim was to determine which tissues express ANGPTL4 in the bovine. Rumen, omasum, abomasum, duodenum, jejunum, ileum, colon, pancreas, liver, and subcutaneous adipose tissue samples were collected postmortem from 2 steers. Abundance of ANGPTL4 messenger RNA was quantified by quantitative real-time PCR, and was most abundant in liver and adipose tissue (P < 0.05). We also detected ANGPTL4 messenger RNA throughout the gastrointestinal tract, although its abundance was approximately 10% of that found in liver and adipose tissue. Western blot analysis revealed that ANGPTL4 protein was most abundant in liver and adipose tissue (P < 0.05), but omasal, abomasal, and ileal samples contained at least 60% as much ANGPTL4 protein as the liver and adipose tissue samples, and the protein was detected in all tissues. Finally, cross-sections of the liver, pancreas, and rumen wall were used for indirect immunofluorescent detection of ANGPTL4. Despite the low abundance of ANGPTL4 measured by quantitative real-time PCR and Western blot in ruminal tissue, immunofluorescence demonstrated that expression of ANGPTL4 in ruminal epithelial cells was equivalent to or greater than that in liver hepatocytes. These findings indicate that, as in other species studied, liver and adipose tissue are key sources of ANGPTL4 in cattle. However, the protein was also highly abundant in ruminal epithelium, making it possible that commensal microbes may influence ANGPTL4 synthesis and secretion in the ruminant gastrointestinal tract. Key words: angiopoietin-like protein, bovine, fasting-induced adipose factor, steer doi: 10.2527/jas.2009-2258

The quality and value of the carcass in domestic meat animals are reflected in its protein and fat content. Preadipocytes and adipocytes are important in establishing the overall fatness of a carcass, as well as being the main contributors to the marbling component needed for consumer preference of meat products. Although some fat accumulation is essential, any excess fat that is deposited into adipose depots other than the marbling fraction is energetically unfavorable and reduces efficiency of production. Hence, this review is focused on current knowledge about the biology and regulation of the important cells of adipose tissue: preadipocytes and adipocytes. Key words: adipocyte, meat animal, preadipocyte, review

A total of 600 crossbred pigs, whereof 56 were randomly selected for more in-depth studies of carcass and pork quality, were employed to test different tuna oil feeding regimens. The focus was put on the efficiency to enrich lean and adipose tissue with n-3 fatty acids and the expression of adverse side-effects on performance, carcass, and pork quality. The 4 treatments were 0% tuna oil in diet (T0; control), 1% of unrefined tuna oil in diet fed from 35 to 90 kg of BW (T1), and 3% of unrefined tuna oil in diet offered during the early (35 to 60 kg of BW; T3-E) or late stage of fattening (75 to 90 kg of BW; T3-L). With this arrangement, pigs consumed equal lifetime amounts of tuna oil (approximately 1.6 kg per pig). None of the tuna oil treatments had significant effects on performance. There were no differences in carcass quality among tuna oil groups except for group T3-E where carcasses and loin chops were fatter than those of the other groups. Water-holding capacity and texture of the loin as well as firmness and melting properties of the backfat remained widely unaffected by the treatments. Tuna oil feeding resulted in a lighter, less red and less yellow backfat and was found to increase the proportion of n-3 fatty acids to total fatty acids in all treatments. This especially concerned eicosapentaenoic acid and docosahexaenoic acid, but not [alpha]-linolenic acid. There was also a slight increase in oleic acid, whereas n-6 fatty acids largely decreased. Feeding tuna oil during a short period at the end of fattening (T3-L) or permanently during fattening (T1) proved to be similarly efficient in increasing n-3 fatty acid content of lean and adipose tissue (to about 1.6-fold of T0). By contrast, only two-thirds of this increase was found when the same amount of tuna oil had been fed exclusively during early fattening (T3-E). The decreased efficiency in T3-E was associated with better sensory flavor, overall acceptability grading, and oxidative status. The results show that, particularly under the condition of a continuous supply, much of the n-3 fatty acids ingested in early fattening can be recovered in pork. These findings give farmers flexibility as to when and how pork can be enriched in n-3 fatty acids with fish oil. Key words: fatty acid, fish oil, n-3, pig, pork, tuna oil

The common practice in North American feedlot industries is to add antibiotics to the diet to prevent disease and improve both BW gain and feed efficiency. In this study, 240 crossbred steer calves were backgrounded on a 54% silage diet for 80 d and fed a finishing diet consisting of 81% barley grain, 10% barley silage, and 7.5% supplement (DM basis) with and without in-feed antibiotics for approximately 120 d. Calves were assigned to 1 of 5 treatments: a control with no antibiotics, 11 mg/kg of chlortetracycline, 44 mg/kg of chlortetracycline, 44 mg/kg of chlortetracycline plus 44 mg/kg of sulfamethazine, and 11 mg/ kg of tylosin phosphate. A combination of GLC and silver-ion HPLC methods was used to analyze the fatty acid composition of brisket adipose tissue, with emphasis on trans-18:1 and CLA isomers. The inclusion of nonionophore antibiotics in the diet had little effect on the fatty acid composition, except that feeding either 44 mg/kg of chlortetracycline or 11 mg/kg of tylosin caused small increases in 9c-14:1 and 16:0 relative to the control (0.26 and 0.9 g/100 g of total fatty acids, respectively). Likewise, profiles of trans-18:1 and CLA isomers were unchanged by antibiotics, but across treatments the predominant trans-18:1 isomer was 10t-18:1 (where t = trans; 3.22%) at 3 times the concentration of the second most abundant isomer (11t-118:l; vaccenic acid, 1.05%). Rumenic acid (9c,11t-18:2, where c = cis) was the major CLA isomer at 61% of total CLA, followed by 7t,9c-18:2 at 9%. Because no other effects on fatty acid composition were evident, data for trans-18:1 and CLA were pooled across treatments to investigate possible relationships among rumen PUFA metabolites. The total trans-18:1 content in brisket adipose tissue was positively correlated with 10t-18:l, but not with 11t-18:l, whereas the total CLA was positively correlated with 9c,11t-18:2, but not with 7t,9c-18:2. The 7t,9c-18:2 was, however, positively correlated with 10t-18:l and 6t/7t/8t-18:1 but was negatively correlated with rumenic acid. These metabolic interrelationships suggest the presence of bacterial populations with distinct pathways for PUFA biohydrogenation in which either 10t-18:l or 11t-18:1 predominate. Overall, the nonionophore antibiotics tested did not appreciably change adipose tissue composition and consequently could not be used to improve the trans-18:1 or CLA profile (i.e., increase vaccenic and rumenic acids at the expense of 10t-18:l). Key words: adipose tissue, antibiotic, beef, conjugated linoleic acid, trans-18:1

Vitamin A (retinoic acid) is known to be an adipogenic factor influencing both in vitro and in vivo cell development. This study aimed to determine its effect on lamb adipose tissue development during the early phase of postnatal development until 100 d of age. Male lambs (n = 24) of the Rasa Aragonesa breed were used. At birth, lambs were assigned to 1 of 2 experimental groups: 1) the control (C) group, which received feed without vitamin A supplementation, and 2) the vitamin A (V) group, which received a supplement of 500,000 IU/animal twice per week from birth to slaughter. The effect of vitamin A supplementation was studied at 16.8 [+ or -] 0.35 kg of BW (58 [+ or -] 0.7 d of age) and at 27.8 [+ or -] 0.78 kg of BW (101 [+ or -] 6.5 d of age). The variables of lamb growth, carcass, LM area, and lipid content were analyzed. To study adipose tissue development, the amount of adipose tissue accumulated, the size and number of adipocytes, and lipogenic enzyme activities (glycerol 3-phosphate dehydrogenase, fatty acid synthase, and glucose 6-phosphate dehydrogenase) of the omental, perirenal, and s.c. depots were quantified. Results showed that vitamin A supplementation had no influence on growth, carcass variables, LM area, and lipid content during lamb growth but that the number of adipocytes in the perirenal depot was 30% greater in lambs of the V group (P < 0.05) and that these lambs had smaller adipocytes in the omental and perirenal depots (P = 0.06) at 28 kg of BW (101 d of age). These results suggest that the intake of this level of vitamin A during the whole period of growth of the lambs influenced the processes of hyperplasia and hypertrophy in the different adipose depots, depending on their degree of maturity. Key words: adipose tissue, growth, lamb, vitamin A

The concentration of CLA in adipose tissue can be increased in ruminants by feeding pasture and extruded soybeans. The objective of this study was to evaluate maternal supplementation of raw (RS) or extruded (ES) soybeans on the concentrations of CLA in milk fat of cows and s.c. adipose tissue of suckling calves. Thirty-two spring-calving cows (BW 624 [+ or -] 76 kg; BCS 3.5 [+ or -] 0.4; mean [+ or -] SD) and calves (BW 127 [+ or -] 15 kg) were separated into 2 groups. Cows were distributed to have 8 calves of each sex in both groups. When animals were turned out to pasture, dams received 2 kg/d of either RS or ES. Dietary treatments had no effect on average milk intake (P = 0.22) and pasture forage intake (P = 0.13) for calves over the course of the grazing season. As a result, no effect of treatments was observed on ADG (P = 0.26). At weaning, milk fat content of CLA reached 15.4 and 24.2 mg/g of total fatty acids for cows fed RS and ES, respectively (P = 0.02). The CLA concentrations in adipose tissue were 16.9 and 25.0 mg/g of total fatty acids for calves suckling dams fed RS and ES, respectively (P < 0.001). Overall, results demonstrated supplementing grazing cows with ES increased CLA content in milk and adipose tissue of suckling calves. Key words: conjugated linoleic acid, extruded soybean, nursing beef cow, pasture, subcutaneous adipose tissue, suckling calf

Fresh pork loins (n = 290) were selected from a commercial packing facility based on subjective marbling of the intact loin and 24-h pH to determine the influence of marbling on sensory attributes. The study was designed using pigs from a similar genetic background, raised in similar production facilities, and slaughtered on a single kill day to minimize the effects of genetics, management, environment, and slaughter day. Loins were vacuum-packaged, transported to the University of Illinois Meat Science Laboratory, and aged for 7 d, after which a chop was removed from the area of the tenth rib for proximate analysis. Quality measurements, including National Pork Producers Council color, marbling, and firmness, ultimate pH, Minolta [L.sup.*], [a.sup.*], and [b.sup.*], and drip loss, were determined after aging. After the proximate composition was completed, 150 loins were selected to provide a continuous and uniform distribution of extractable lipid, ranging from 1 to 8%, and a pH range from 5.5 to 5.8. Trained sensory panel analyses (end point cooking temperatures of 62, 71, or 80[degrees]C) as well as measurement of Warner-Bratzler shear force (cooked to 71[degrees]C) were performed on chops from the 150 loins. Consumer evaluation was also conducted on a subset (n = 40) of these loins, which were broken down into 5 discrete levels of intramuscular lipid, with averages of 1.6, 2.5, 3.6, 4.5, and 5.7% extractable lipid. Consumers were also asked to select the chops they would most prefer from a retail display case based on the amount of marbling present. Results from the consumer portion of the study indicated that intramuscular fat content had limited effects on perceived tenderness, juiciness, pork flavor, and oiliness; some significant differences (P < 0.05)were detectable, but they were numerically small. Most consumers also selected lean chops from the retail case, with nearly 50% selecting chops with less than 1.7% extractable lipid. Warner-Bratzler shear force was negatively related (P < 0.0001) to extractable lipid, with an [R.sup.2] value of 0.10. Results from the trained panel sensory analysis indicate that the percentage of extractable lipid did not correlate strongly with perceived tenderness, juiciness, or pork flavor for this group of pork loins that was controlled for genetics, pH, management, and day of slaughter. Key words: consumer, lipid, marbling, pork, quality, sensory

A feeding trial was designed to examine the effects of copper sulfate pentahydrate (Cu[SO.sub.4] * 5[H.sub.2]O) on the fatty acid composition and oxidative stability in muscle and adipose tissues of Boer x Spanish goat kids. Fifteen (n = 5 per treatment) goats were fed 0, 100, or 200 mg of supplemental Cu per day as copper sulfate for 98 d. The animals were slaughtered, and LM, s.c. adipose from the sternal region, and mesenteric adipose tissues were collected. Total lipids were extracted with chloroform:methanol (2:1), methylated and isolated via GLC from all tissues. The subsequent peaks were then positively identified by mass spectrom etry. Thiobarbituric acid-reactive substances were measured also. In s.c. adipose, dietary Cu significantly decreased C14:0 (P = 0.03) and C16:0 (P = 0.01). In muscle, C15:0 (P = 0.03) was linearly increased by Cu. Dietary Cu supplementation did not influence oxidative stability in goat muscle or s.c. adipose. Copper supplementation at 200 mg/d resulted in a significant increase in malondialdehyde in mesenteric adipose (P = 0.01) compared with the 0 or 100 mg/d groups. These results indicate that lipid composition may differ from depot to depot and that depending on the depot, dietary Cu seems to elicit a variable response on the fatty acid composition. Key words: copper, diet, goat, lipid

This study was conducted to describe the dose-response curve relating the concentration of carotenoid pigments in plasma and reflectance spectrum characteristics of fat to the carotenoid intake level in sheep, and to investigate the extent to which incorporation of dehydrated alfalfa in the diet affects the reliability of the discrimination between concentrate-fed and pasture-fed lambs based on these measurements. In Exp. 1, 6 treatments were compared in individually penned lambs: feeding 0, 250, 500, 750, 1,000, or 1,250 g/d of dehydrated alfalfa for 60 d before slaughter. Each treatment (T0 to T1,250) consisted of 8 male Romanov x Berrichon lambs with an initial average BW of 24.8 kg (SD 2.6). All lambs received straw for ad libitum intake and TO to T1,000 lambs received a concentrate free of green vegetative matter in amounts to produce similar ADG in all treatments. In Exp. 2, 33 male Romanov x Berrichon lambs grazed a natural pasture maintained in a leafy green vegetative stage for at least 59 d before slaughter. Initial BW when turning out to pasture was 14.2 kg (SD 2.3). Plasma carotenoid concentration was measured at slaughter by spectrophotometry. Reflectance spectrum, lightness, redness, and yellowness were measured after 24 h of shrinkage in subcutaneous caudal and perirenal fat. The spectra were translated to 0 reflectance at 510 nm, and the integral of the translated spectrum was calculated between 450 and 510 nm (i.e., the range of light absorption by carotenoids). Reflectance measurement was replicated 5 times, from which we calculated the absolute value of the mean integral (AVMI). In Exp. 1, plasma carotenoid concentration at slaughter (PCCS) increased linearly with mean daily carotenoid intake (P < 0.01). Both subcutaneous caudal and perirenal fat AVMI increased linearly (P < 0.01) with mean daily carotenoid intake and PCCS, the slopes of the regressions being greater for perirenal than for subcutaneous caudal fat. The mean PCCS was greater for lambs of Exp. 2 than for lambs on any treatment of Exp. 1 (P < 0.01). We established the dose-response curves relating PCCS and AVMI of subcutaneous and perirenal fat to carotenoid intake level. The combined use of PCCS and of perirenal fat AVMI enabled discrimination of pasture-fed lambs of Exp. 2 from the lambs of Exp. 1 that received up to 500 g/d of dehydrated alfalfa. Key words: alfalfa, carcass, carotenoid, fat, reflectance, sheep

An excessive accumulation of androstenone in pig adipose tissue is a major contributor to the phenomenon of boar taint. Androstenone deposition is dependent on the rate of androstenone biosynthesis in testis and androstenone degradation in liver. The aim of the current study was to examine the possibility of the existence of breed-specific mechanisms controlling androstenone accumulation in pig adipose tissue. The specific objective was to investigate the expression of some of the key enzymes involved in testicular and hepatic androstenone metabolism in pigs of 2 breeds by using animals with high and low androstenone concentrations within each breed. The study was conducted with Norwegian Landrace (N. Landrace) and Duroc boars. The mean androstenone values for the low- and high-androstenone groups were 0.1 [+ or -] 0.01 [micro]g/g and 7.58 [+ or -] 0.68 [micro]g/g for N. Landrace boars, and 0.22 [+ or -] 0.04 [micro]g/ g and 13.55 [+ or -] 1.14 [micro]g/g for Duroc boars. The enzymes investigated were 3[beta]-hydroxysteroid dehydrogenase (3[beta]-HSD), cytochrome P450-c17, and sulfotransferase 2B1 (SULT2B1). Expression of cytochrome P450-c17 in liver and testis did not differ between animals with high and low androstenone concentrations in either the N. Landrace or Duroc breed. Expression of hepatic 3[beta]-HSD, which catalyzes the first stage of androstenone degradation, was decreased in high-androstenone N. Landrace boars (P < 0.01), but not in high-androstenone Duroc boars. In contrast, the expression of hepatic SULT2B1, which catalyzes the second stage of steroid catabolism, was decreased in high-androstenone Duroc animals (P < 0.05), but not in high-androstenone N. Landrace animals. Sulfotransferase 2B1 was also inhibited in testis of high-androstenone pigs of both breeds compared with low-androstenone animals. We report breed differences in expression of the androstenone-metabolizing enzymes 3[beta]-HSD and SULT2B1 in the liver of high- and low-androstenone pigs. It is suggested that accumulation of androstenone in adipose tissue of N. Landrace boars might be related to a low rate of hepatic androstenone degradation in metabolic stage I, whereas the high androstenone concentration in Duroc boars might be related to a low rate of androstenone metabolism in metabolic stage II. Key words: androstenone, breed, cytochrome P450-c17, 3[beta]-hydroxysteroid dehydrogenase, pig, sulfotransferase 2B1

This work investigated the metabolic basis for the variability of carcass and i.m. adiposity in cattle. Our hypothesis was that the comparison of extreme breeds for adiposity might allow for the identification of some metabolic pathways determinant for carcass and i.m. adiposity. Thus, 23- to 28-mo-old steers of 3 breeds, 2 with high [Angus or Japanese Black x Angus (J. Black cross)] and 1 with low (Limousin) i.m. and carcass adiposity, were used to measure activities or mRNA levels, or both, of enzymes involved in de novo lipogenesis [acetyl-coA carboxylase, fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme], circulating triacylglycerol (TAG) uptake (lipoprotein lipase), and fatty acid esterification (glycerol-3-phosphate dehydrogenase), as well as the mRNA level of leptin, an adiposity-related factor. In a first study, enzyme activities were assayed in the s.c. adipose tissue (AT), the oxidative rectus abdominis, and the glycolytic semitendinosus muscles from steers finished for 6 mo. Compared with Angus or J. Black cross, Limousin steers had a 27% less (P = 0.003) rib fat thickhess, and 23 and 29% less (P [less than or equal to] 0.02) FAS and G6PDH activities in s.c. AT. In rectus abdominis and semitendinosus, the 75% less (P < 0.001) TAG content was concomitant with 50% less (P < 0.001) G6PDH activity. In a second study, enzyme activities plus mRNA levels were assayed in an oxido-glycolytic muscle, the longissimus thoracis (LT), in the i.m. AT dissected from LT, and in s.c. AT from the same Limousin steers and from Angus steers finished for 10 mo. Compared with Angus, the 50% less (P < 0.001) rib fat thickness in Limousin contrasted with the 1.1- to 5.8-fold greater (P [less than or equal to] 0.02) mRNA levels or activities, or both, of acetyl-coA carboxylase, G6PDH, lipoprotein lipase, and glycerol-3-phosphate dehydrogenase in s.c. AT. Conversely, the 90% less (P < 0.001) TAG content in Limousin LT was concomitant to the 79 and 83% less (P [less than or equal to] 0.002) G6PDH activity and leptin mRNA level. Such differences could arise from a greater number of adipocytes in LT from Angus steers because no difference was found between Limousin and Angus for G6PDH activity and leptin mRNA in i.m. AT. We conclude that FAS and G6PDH in s.c. AT could be involved in differences in carcass adiposity, but this relationship disappeared when the fatness increased strongly. Leptin and G6PDH are related to the expression of marbling whatever the body condition and thus could be relevant indicators of marbling in beef cattle. Key words: adipose tissue, bovine, leptin, lipogenic activity, muscle