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Abstract
TG analysis of lipids is a suitable analytical method that offers the possibility to correlate kinetic parameters of thermal degradation (activation energy) and lipid composition. For this purpose, an inert (nitrogen) or oxidising atmosphere (oxygen) was applied during the thermal treatment (30–220°C) of lipids isolated from intramuscular and fatty tissues (L-IMT and L-FT) of deers and does. Prior to investigation, the extracted samples of lipids were kept at −24°C or +4°C for nine months, thus enabling detection of the influence of storage temperature on the thermal behaviour of the lipids.
An experiment was performed to study the effect of different vegetable oils containing high proportions of PUFA (5% soybean oil, SBO; and sunflower oil, SFO; respectively, in the DM of concentrate) or grass silage (150 g DM/d/animal, GSL) on the level of conjugated linoleic acid (CLA) isomers and other C18 fatty acids in muscle and adipose tissues of growing lambs. Control animals were fed on the same diet as SBO or SFO groups; however, instead of vegetable oils hydrogenated palm oil containing low level of PUFA was applied. In both muscle and adipose samples tested c-9, t-11 C18:2 showed the highest levels among the CLA isomers, however, t-10, c-12 CLA could also be measured in lower proportions. Considering vegetable oil supplementations, only SBO resulted in a significantly higher level of c-9, t-11 CLA in the triceps brachii muscle as compared to the control. Such a difference could not be detected in either the gracilis muscle or in the adipose tissue samples. However, lambs fed on the GSL diet had significantly higher c-9, t-11 CLA levels in both the triceps and gracilis muscles and lower proportion of t-10, c-12 CLA in the adipose than those fed on the control, SBO and SFO diets, respectively. Concerning C18 fatty acids other than CLA, SFO lambs showed significantly higher proportions of C18:1n-9 than those of control animals in both muscles and perirenal fat tested. However, level of C18:0 in the adipose tissue of GSL lambs was significantly lower than that of the animals fed both control or vegetable oil supplemented diets. Results of this experiments show that different dietary fatty acid sources have various potential to increase CLA contents in the meat of lambs. In addition to vegetable oils rich in PUFA, grass silage may be good dietary source for nutritional manipulation of the fatty acid composition of lamb meat.
Total lipids of the intramuscular tissue of fallow deer
Non-isothermal, non-oxidative and oxidative TG
Abstract
In this study non-isothermal non-oxidative and oxidative TG analysis was applied as a method for determining the thermal stability of the total lipids extracted from raw and maturing intramuscular tissue of fallow deer (Cervus Dama Dama L.). The total lipids were extracted from intramuscular tissue, according to the Folch method and stored for nine months at +4 and −18�C. The changes in the thermal stability of the total lipids during non-oxidative and oxidative TG analysis were correlated with the lipid composition, i.e. fatty acid composition. The Flynn-Wall method was used to determine the values of the activation energy of thermal degradation of the total lipids in a defined mass loss range.
Buchtová, H., Svobodová, Z., Krizek, Z., Vácha, F., Kocour, M., Velísek, J. (2007) Fatty acid composition in intramuscular lipids of experimental scaly crossbreds in 3-year-old common carp ( Cyprinus carpio L.). Acta Vet. Brno 76 , 73
ratio was calculated based on three bands and expressed as mean ± standard deviation. * P < 0.05, ** P < 0.01, *** P < 0.001. n = 5 The effects of acute aerobic exercise and 3-OBA treatment on intramuscular lipid changes-related proteins To