Concentrations of contaminants in muscle of the American alligator in Florida

Samples of tail muscle from 32 American alligators (Alligator mississippiensis) in Florida were analyzed for contaminant concentrations to provide preliminary information on the potential public health hazard of meat consumption. Detectable levels were found for eight metals; copper, zinc, iron, chromium, mercury, lead, cadmium and arsenic. Mean residue was highest for mercury (geometric mean = 0.61 ppm). DDE, DDD, DDT, dieldrin, heptachlor epoxide, lindane, and PCB's were found. Mean residue concentrations were compared by lake. Alligators appeared to be suitable monitors of environmental pollution. Concentrations of contaminants found in these animals probably pose little threat to public health. However, recommendations must await analysis of larger sample sizes and information on amount and frequency of meat consumption. Alligators killed for human consumption should continue to be monitored for contaminant residues.     

Environmental pollutant and necropsy data for ospreys from the eastern United States, 1975-1982

Twenty-three ospreys (Pandion haliaetus) found dead or moribund in the eastern United States during 1975-1982 were necropsied and selected tissues were analyzed for organochlorines and metals. Major causes or factors contributing to death were trauma, impact injuries, and emaciation. DDE was detected in 96% of the osprey carcases, DDD in 65%, DDT and heptachlor epoxide in 13%, dieldrin, oxychlordane, and cis-nonachlor in 35%, cis-chlordane in 52%, trans-nonachlor in 45%, and PCB's in 83%. Carcasses of immature ospreys from the Chesapeake Bay had significantly lower concentrations of DDE, DDD + DDT, cis-chlordane, and PCB's than carcasses of adults from the same area. Concentrations of some organochlorines in ospreys from the Chesapeake Bay declined significantly from 1971-1973 to 1975-1982. Significant differences in concentrations of certain metals in the ospreys' livers were noted between time periods, and sex and age groups for birds from the Chesapeake Bay. During 1975-1982, adults had significantly lower concentrations of chromium, copper, and arsenic than immatures and nestlings, and adult males had higher mercury concentrations than adult females. Adult females had lower zinc concentrations in 1975-1982 than in 1971-1973. Immatures and nestlings had higher concentrations of chromium and lead in 1975-1982 than in 1971-1973. A slightly elevated concentration of chromium (1.7 ppm) or arsenic (3.2 ppm) was found in the livers of individual ospreys. Several ospreys had elevated concentrations of mercury in their livers; two ospreys had more than 20 ppm which may have contributed to their deaths.     

Withdrawal rates of DDT from chickens treated with diphenylhydantoin.

Male and female chickens of a broiler-type strain were fed, from 1 day old to 5 weeks of age, diets containing 0, 2.5, or 15.0 p.p.m. (mg/kg) 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT). Then the diets with pesticide were withdrawn and the chickens were fed dietary levels of diphenylhydantoin (DPH) at 0, 100, or 250 p.p.m. Adipose-tissue and liver samples were obtained on days 0, 10, 20, and 30 following withdrawal of diets with pesticides to determine DPH effect on DDT, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) levels. DPH had no effect on the concentration of DDT and DDE in adipose tissue; their levels declined at a rate having a half-life value of 16 days. DDD was not detected in adipose tissue. DDT accounted for 87% of the adipose residues on day 0, but 66% of the residues at day 30. DPH had no effect on the concentrations of DDT and DDE in livers of chickens fed 15.0 p.p.m. DDT, but did significantly reduce the levels of DDD by 28 and 54% for levels of 100 and 250 p.p.m. DPH, respectively. The similarity of these data to studies on dairy cows and humans, and the dissimilarity to data from rat studies were discussed.     

Investigations into mechanisms responsible for seizures induced by chlorinated hydrocarbon insecticides: the role of brain ammonia and glutamine in convulsions in the rat and cockerel

Abstract— Seizures were produced in adult female rats and in cockerels (Gallus domesticusL.) after the intracarotid administration of four structurally-unrelated chlorinated hydrocarbon insecticides. The temporal relationship of the course of the convulsions to levels in whole brain of ammonia and glutamine was examined. High levels of brain ammonia occurred in rats and cockerels poisoned acutely with lindane, dieldrin, heptachlor and DDT. The intensity of convulsions and other neurological signs coincided with and were directly correlated with the increases in brain ammonia, whereas interictal periods were associated with decreased levels of ammonia. In both species the order of drug toxicity was lindane > dieldrin > heptachlor > DDT. Significantly elevated levels of brain glutamine were induced in the cockerels after administration of all four insecticides. In contrast, increased levels of glutamine in rats were found only in those intoxicated with lindane and dieldrin. Although the ammonia-binding mechanism (conversion of free ammonia into glutamine) was saturated throughout the experiments in both the rats and cockerels, the latter were more resistant to ammonia toxicity by virtue of being able to convert free ammonia into glutamine more efficiently than rats. These data, together with data reported by others, lead to the conclusion that the four structurally-unrelated chlorinated hydrocarbon insecticides probably induced convulsions in both species by a common mechanism, involving interference with the production and/or utilization of ammonia.     

Histological assessment of selected tissues in tigerfish (Hydrocynus vittatus Castelnau, 1861) from the Sanyati Basin,Lake Kariba,Zimbabwe: a DDT-sprayed area

A pilot investigation was conducted in 2014 in the Sanyati Basin of Lake Kariba to ascertain whether long-term DDT spraying in the Kariba catchment had a negative effect on fish health. The aim was to assess the health of tigerfish, Hydrocynus vittatus, by means of histological analysis and to analyse water, sediment and tissue samples for bioaccumulated levels of chlorinated pesticides, including DDT. Eighteen tigerfish were collected by seine netting along the north-eastern shoreline of the Sanyati Basin in April 2014 and samples of their gill, liver, kidney, muscle and brain tissue were processed for histology and assessed using light microscopy. No detectable levels of DDT and/or its metabolites were found in the water or sediment samples and only a low concentration of p,p′-DDE in fish tissues. No major histological alterations were observed in the fish tissues. Consequently, there seems to be no risk of DDT exposure following the consumption of tigerfish from the Sanyati Basin of Lake Kariba. These results were unexpected, given the historical use of DDT within the current study area. It is recommended that these findings be compared with those from other regions of Lake Kariba.     

The intracellular distribution and activities of phosphoenolpyruvate carboxykinase isozymes in various tissues of several mammals and birds.

1. The intracellular distribution and/or activities of phosphoenolpyruvate carboxykinase isozymes were determined in liver, kidney, gastrointestinal mucosa, adipose, skeletal muscle, brain, spleen, lung and heart of fed and fasted rabbits, guinea pigs, rats, chickens and pigeons. 2. Liver and kidney of all species contained the highest enzyme activity/g. 3. Carboxykinase activity/g gastrointestinal mucosa of rabbits was quite high compared to the low activity in guinea pig and rat mucosa and essentially undetectable activity in chicken and pigeon mucosa. 4. Activity/g was high in rat brown adipose. 5. Low carboxykinase activity/g was found in skeletal muscle of all species and in white adipose of guinea pig, rabbit and rat although activity was undetectable in white adipose of chicken and pigeon. 6. Carboxykinase activity was essentially undetectable in brain, spleen, lung and heart of all species.     

Changes of insulin binding in rat tissues after exposure to stress.

The effects of various stressors on insulin receptors in adipose, liver and skeletal muscle tissues were studied in rats exposed to acute or repeated stress. Adult male rats were exposed to immobilization (IMO) for 2.5 hours daily for 1, 7 and 42 days, or to hypokinesia (HK) for 1, 7 and 21 days. We determined the values of specific insulin binding (SIB) and insulin receptor binding capacity (IR) of plasma cell membranes from adipose, liver and muscle tissue (IMO groups), or insulin binding to isolated adipocytes and hepatocytes (HK groups). A significant decrease of SIB and IR was observed in rats exposed to acute stress (1x IMO) in muscle, adipose and liver tissues. However, in animals exposed to repeated stress (7x and 42x IMO), SIB and IR were diminished in the muscle tissue, whereas no significant changes were noted in the liver and adipose tissue. When tissue samples were collected 3-24 hours after exposure to IMO stress, no changes of SIB and IR were found in liver and adipose tissue, but insulin binding was lowered in skeletal muscles. In animals exposed to HK for one day, a decrease of SIB and IR was found in isolated adipocytes, but no changes in insulin binding were noted in the liver tissue. In rats exposed to HK for 7 and 21 days, values of IR were similar as in control group. Our results indicate a) the different changes of IR in the liver, fat and muscle tissues after exposure to stress situations, b) a long-term decrease of insulin binding in muscles of rats exposed to repeated IMO stress, and c) the return of reduced SIB and IR (induced by acute stress) to control values in the liver and adipose tissue after a short recovery period.     

Effect of high-fat diet on the expression of proteins in muscle, adipose tissues, and liver of C57BL/6 mice

In the present study, the effect of a high fat diet on the expression of proteins in insulin target tissues was analyzed using a proteomic approach. Gastrocnemius muscle, white and brown adipose tissue, and liver were taken from C57BL/6 mice either fed on a high-fat or a chow diet. Expression levels of approximately 10 000 polypeptides for all the four tissues were assessed by two-dimensional gel electrophoresis (2-DE). Computer-assisted image analysis allowed the detection of 50 significantly (p < 0.05) differentially expressed proteins between obese and lean mice. Interestingly, more than half of these proteins were detected in the brown adipose tissue. The differentially expressed proteins were identified by tandem mass spectrometry. Several stress and redox proteins were modulated in response to the high-fat diet. A key glycolytic enzyme was found to be downregulated in adipose tissues and muscle, suggesting that at elevated plasma fatty acid concentrations, fatty acids compete with glucose as an oxidative fuel source. Furthermore, in brown adipose tissue there were significant changes in mitochondrial enzymes involved in the Krebs tricarboxylic acid (TCA) cycle and in the respiratory chain in response to the high-fat diet. The brown adipose tissue is an energy-dissipating tissue. Our data suggest that the high-fat diet treated mice were increasing energy expenditure to defend against weight gain.     

mRNA expression of genes involved in fatty acid utilization in skeletal muscle and white adipose tissues of sows during lactation

Rodents are able to lower fatty acid utilization in liver and muscle during lactation in order to spare fatty acids for the production of milk triacylglycerols, an effect which is mediated by a down-regulation of peroxisome proliferator-activated receptor α (PPARα). The present study was performed to investigate whether similar fatty acid sparing effects are developing in lactating sows. We considered PPARα and its target genes involved in fatty acid utilization in biopsy samples from muscle and adipose tissue of lactating compared to non-lactating sows. In muscle, PPARα target genes involved in fatty acid utilization were up-regulated during lactation indicating that the fatty acid utilization in muscle was increased. Activation of PPARα was probably due to increased concentrations of non-esterified fatty acids in plasma observed in the lactating sows. In contrast to muscle, PPARα and its target genes involved in β-oxidation in white adipose tissue were down-regulated in early lactation. Overall, the present study shows that sows, unlike rats, are not able to reduce the fatty acid utilization in muscle in order to spare fatty acids for milk production. However, fatty acid oxidation in adipose tissue is lowered during early lactation, an effect that might be helpful to conserve fatty acids released from adipose tissue for the delivery into other tissues, including mammary gland, via the blood.     

Organochlorine pesticides in Cyprinus carpio from Sidi Salem Dam,north-western Tunisia

Cyprinus carpio (Linnaeus, 1758) caught in Sidi Salem Dam in 2011 were analysed for the levels of organochlorine pesticides (OCPs), including hexachlorobenzene (HCB), aldrin, heptachlor, lindane, dieldrin, endrin, and pp′-DDT and its two main metabolites pp′-DDD and pp′-DDE, in order to evaluate the extent of contamination of the dam. Fish were sampled monthly within the dam during 2011. Muscle, liver and gill tissues were analysed by gas chromatography for the determination of OCPs. Samples had variable concentrations of OCPs, ranging from 2.26 to 17.93 ng g?1, 0.59 to 42.67 ng g?1 and 3.30 to 84.27 ng g?1, which were isolated from gills, muscle and liver, respectively. The organochlorine pesticide levels found posed no threat to human health. The highest OCP levels were found in the liver tissues. The pp′-DDE concentrations and their ratios to ΣDDTs indicate aged DDT pollution and suggests that there has been no recent input of technical DDT from the agricultural areas into Sidi Salem Dam.     

Distribution of the UV filter 3-benzylidene camphor in rat following topical application

A straightforward analytical method for determination of 3-benzylidene camphor (3-BC) in rat adipose tissue, brain, liver, muscle, plasma and testis following topical application was developed and validated. Three exposure levels (60, 180 and 540 mg kg(-1) day(-1)) were tested for 65 days in male Sprague-Dawley rats (24 days postnatal). Sample preparation involving homogenization and n-heptane or methanol extraction of the tissue was applied before injection into the LC-ESI-MS-MS system. The response was linear from 2 to 100 microg l(-1) for the qualifier and the quantifier MRM transitions (R(2) (quantifier) > 0.994). Detection limit of the method corresponded to 0.005 microg g(-1) tissue and 12.5 microg l(-1) plasma, respectively. Recovery was determined for all tissues (adipose tissue: 40%; all other tissues: 80-100%) at three individual levels. 3-(4-Methyl benzylidene camphor) (4-MBC) was used throughout the study as internal standard. 3-Benzylidene camphor was detected in all tissues at all exposure levels at concentrations between 0.05 microg g(-1) (liver) and 36 microg g(-1) (adipose tissue) and in plasma at 16-89 microg l(-1). The method allowed for the quantification of 3-benzylidene camphor in all tested tissues following topical application. Furthermore, it was shown that 3-benzylidene camphor can be found in various tissues in the rat following topical application. These findings may suggest that following use of 3-benzylidene camphor containing sunscreen, similar disposition and distribution may occur in humans.     

Physiological mechanism of toxic action of DDT and endrin in two euryhaline freshwater fishes, Anguilla vulgaris and Mugil cephalus

RBC counts, Ht value and Hb content in both species exposed to DDT and endrin concentrations were not significantly different from those of controls. WBC counts in both species exposed to the two pesticides for 96 hr decreased significantly at different concentrations. The variance ratios of cations and anions were consistently more concentrated in the serum of DDT- and endrin-exposed fishes. Serum cholesterol was sharply elevated in all the lots exposed to pesticides. Exposure to sublethal concentrations of DDT and endrin impaired liver function, as evidenced by the transfer of major cations from hepatic tissue to the serum and by elevated serum cholesterol.     

Effects of different doses of resveratrol on body fat and serum parameters in rats fed a hypercaloric diet

Recently resveratrol, a compound naturally occurring in various plants, has been proposed as a potential anti-obesity compound. The aim of the present work was to analyse the effects of different doses of resveratrol on body fat and serum parameters in rats. Thirty-two male Sprague-Dawley rats were randomly divided into four groups and fed on a hypercaloric diet for 6 weeks. The doses oftrans-resveratrol used were 6, 30 and 60 mg/kg body weight/d in RSV1, RSV2 and RSV3 groups respectively. The stability of resveratrol when added to the diet was evaluated. Blood samples were collected, and white adipose tissue from different anatomical locations, interscapular brown adipose tissue, gastrocnemious muscles and liver were weighed. Commercial kits were used to measure serum cholesterol, glucose, triacylglycerols and non-esterified fatty acids. While the lowest dose did not have a body fat reducing effect, the intermediate dose reduced all the white adipose depots. The highest dose significantly reduced mesenteric and subcutaneous depots but not epididymal and perirenal tissues. Although the reduction in all the anatomical locations analysed was 19% in the RSV3 group, in the RSV2 group it was 24%. No significant differences among the experimental groups were found in brown adipose tissue, gastrocnemious muscle or liver weights. Serum parameters were not affected by resveratrol intake because no differences among the experimental groups were observed. These results suggest that resveratrol is a molecule with potential anti-obesity effect. The most effective of the three experimental doses was 30 mg/kg body weight/d.     

Tissue-specific modulation of insulin receptor mRNA levels in adrenaline-treated rats

Insulin receptor (IR) gene expression at the mRNA level was investigated in liver, hindlimb skeletal muscle, and epididymal adipose tissue of rats exposed to prolonged in vivo administration of adrenaline in relation to control rats. In the liver of adrenaline-treated rats, there were no differences in relation to controls when DNA and protein content were measured. In skeletal muscle, only a slight decrease in protein concentration was detected. By contrast, a clear increase in both protein and DNA content was observed in the adipose tissue of treated animals. Northern blot assays revealed two IR mRNA species of approximately 9.5 and 7.5 Kb in the three tissues from controls. Adrenaline treatment induced an increase of approximately 60% in the levels of both RNAs in adipose tissue but not in liver or skeletal muscle. These results provide evidence for an in vivo tissue-specific regulation of IR gene expression at the mRNA level in rats under an experimental condition of excess of catecholamines.     

In vivo tissue specific modulation of rat insulin receptor gene expression in an experimental model of mineralocorticoid excess

Insulin receptor (IR) gene expression at the mRNA level was investigated in hindlimb skeletal muscle, epididymal adipose tissue and in the liver of rats exposed to prolonged in vivo administration of deoxycorticosterone acetate (DOCA). Following treatment, plasma insulin levels were reduced while glucose levels increased compared to values in control rats. DOCA-treated animals showed an increase in blood pressure and a reduction in body weight. This treatment also induced hypokalemia and decreased plasma protein levels. Sodium levels were unaffected. Moreover, no differences in DNA and protein content or in the indicator of cell size (protein/DNA) were observed in the skeletal muscle or adipose tissue of animals. In contrast, there was a clear increase in the protein and DNA contents of the liver with no change in the indicator of cell size. Northern blot assays revealed 2 major IR mRNA species of approximately 9.5 and 7.5 Kb in the 3 tissues from control animals. DOCA treatment induced no change in the levels of either RNA species in skeletal muscle. However, a decrease of approximately 22% was detected in the levels of both species in adipose tissue whereas the liver showed an increase of 64%. These results provide the first evidence for an in vivo tissue-specific modulation of IR mRNA levels under experimental conditions of mineralocorticoid excess.     

Heavy metals in tissues of loggerhead turtles (Caretta caretta) from the northwestern Adriatic Sea

Thirty-five specimens of Caretta caretta were collected dead along the Adriatic Sea coast from the Po Delta to the Reno mouth (Italy). Turtles were classified into four size categories ranging from 24.5 to 74 cm, by measuring the minimum straight-line carapace length (MSCL). Cd, Cu, Fe, Mn, Ni, and Zn levels were assessed in liver, lung, muscle and adipose tissue. Cd, Cu and Fe mainly accumulated in the liver (8.9, 23.7 and 1180 mg/kg dry mass [d.w.], respectively), and Mn in the lung (29.5 mg/kg d.w.). Levels of Ni were higher in adipose (22 mg/kg d.w.) than other tissues, while Zn concentrations were higher in muscle (about 140 mg/kg d.w.). Negative correlations with size were established for Zn in liver and Cu in adipose tissue, while positive correlations were observed for Mn and Ni in adipose tissue. Metal concentrations did not differ between males and females, nor between individuals found stranded and those victims of by-catch. On average, Cd, Cu, Mn and Ni concentrations in our specimens were higher than in loggerhead turtles and other species living in other areas. We hypothesize that trace metals could be used as "acquired markers" to help investigate migration routes of C. caretta.     

Drug distribution studies with microdialysis: I. Tissue dependent difference in recovery between caffeine and theophylline

Microdialysis was applied to estimate concentrations of caffeine and theophylline in vitro or in vivo in blood, adipose tissue, muscle, liver and brain of rats. The in vivo and in vitro recovery of a compound was estimated by perfusing the dialysis probe with varying concentrations of caffeine and theophylline. The difference between the concentration in the dialysate and the concentration in the perfusion medium was plotted against the concentration in the perfusion medium and the slope of the resulting line was taken as an estimate of the recovery (difference method). In all experiments caffeine (20 mg/kg sc) and theophylline (20 mg/kg sc) were administered simultaneously. The recovery in vitro was virtually identical for caffeine and theophylline. The in vivo recovery of theophylline was significantly smaller than the recovery of caffeine in brain, liver, muscle and adipose tissue. The difference in recovery was significantly larger in the brain than in other tissues. The results show that the transport of a substance from the tissue to the dialysis probe may differ between tissues and between chemically very similar compounds. It is shown that the recovery of theophylline rapidly declines after death ensues which shows that energy-dependent processes are involved in the transport to the dialysis probe and not solely passive diffusion. It is suggested the differences in transport over brain capillaries explain the difference between caffeine and theophylline. It is concluded that the use of internal standards in microdialysis experiments requires validation in every specific application.     

Partial structure and hormonal regulation of rabbit liver inhibitor-1; distribution of inhibitor-1 and inhibitor-2 in rabbit and rat tissues

Inhibitor-1 purified from rabbit liver could not be distinguished from the skeletal muscle protein by chromatographic, electrophoretic and immunological criteria. Amino acid sequences comprising 68% of rabbit liver inhibitor-1 were identical to the skeletal muscle protein indicating that they are products of a single gene. Total inhibitor-1 activity in heat-treated rabbit liver extracts was similar to that in skeletal muscle extracts, and the phosphorylation state of inhibitor-1 increased from 14% to 42% in rabbit liver in vivo after an intravenous injection of glucagon. Monospecific antibodies to rabbit skeletal muscle inhibitor-1 recognised a single major protein of identical electrophoretic mobility (26 kDa) in each rabbit tissue examined (skeletal muscle, liver, brain, heart, kidney, uterus and adipose). The antibodies also recognised a single major (30 kDa) protein in the same rat tissues, except liver. The results show that while there are interspecies differences in apparent molecular mass, inhibitor-1 is likely to be the same gene product in each mammalian tissue. Inhibitor-1 was not detected in rat liver, either by activity measurements or immunoblotting, irrespective of the age, sex or strain of the animals. Immunoblotting also failed to detect inhibitor-1 in mouse liver, although it was present in guinea pig, porcine and sheep liver. The absence of inhibitor-1 in rat liver indicates that phosphorylation of this protein cannot underlie the increased phosphorylation of hydroxymethylglutaryl-CoA reductase observed after stimulation by glucagon. Monospecific antibodies to rabbit skeletal muscle inhibitor-2 recognised a 31 kDa protein in each rabbit tissue, and a 33 kDa protein in all rat tissues including liver. The results suggest that inhibitor-2 is the same gene product in each mammalian tissue.     

Aspartate- and tyrosine transaminase activities in the organs of the rat during its breeding cycle

The aspartate- and tyrosine transaminase activities of liver kidney, brain, hind leg striated muscle, skin, adipose tissue, small intestine and stomach of pregnant, lactating and post-lactating rats were determined. The ratios of activities between both enzymes were uniform in the different tissues studied, with minimal values for liver and adipose tissue. The patterns and activity ratios found during the breeding cycle of the rat agreed with tyrosine transaminase being an independent entity of aspartate transaminase in liver and adipose tissue, coexisting to some degree in most other tissues and being probably only an artifact (according to recent findings in the literature) in brain, muscle and intestine. The different patterns of change found during this period in most organs suggest different hormonal regulation and help support the possibility of an independent r?le for tyrosine transaminase in them.     

Fatty acid composition and conjugated linoleic acid content of different tissues in rats fed individual conjugated linoleic acid isomers given as triacylglycerols small star,filled

HEAT TREATMENT OF VEGETABLE OILS GAVE RISE TO FOUR MAIN CONJUGATED LINOLEIC ACID (CLA) ISOMERS : the 9c,11t, 9t,11t, 10t,12c and 10t,12t. The diet of male Wistar rats was supplemented with 150 mg/day either 9c,11t-, 9t,11t-, 10t,12c- or 10t,12t CLA isomers for 6 days and their effects on lipid composition were investigated in liver, heart, skeletal muscle Gastrocnemius, kidneys, brain and adipose tissue. The incorporation of all isomers was low (< 1.4%) and the level was as follows : adipose tissue > Gastrocnemius > liver, kidneys > brain. The main changes in the overall lipid composition were observed in skeletal muscle (Gastrocnemius) and in heart and were associated with feeding the 10t,12c and 10t,12t isomers. The diet enriched in 10t,12t CLA decreased the total long chain polyunsaturated fatty acid proportion in Gastrocnemius (from 18.4% to 14.4%) and increased that of 20:4 n-6 in heart (from 16.9 to 19.3%). The diet enriched in 10t,12c CLA decreased the monounsaturated fatty acid proportion in Gastrocnemius (from 32.0 to 26.1%) and produced an effect similar to the 10t,12t in heart. By contrast, the 9c,11t and 9t,11t isomers did not affect fatty acid composition in all tissues and organs. We concluded that ingestion of 10t,12c and 10t,12t CLA present in oils and in CLA mixtures could change muscle lipid composition.