Doran (nee Udovikova), Olena

Moule, S. K.

Wood, J. D.

English

UWE Bristol Research Repository

205The effect of age on the levels of lipogenic enzymes in subcutaneous fat and muscle of pigsE.Doran1, S.K.Moule2 and J.D.Wood11Department of Clinical Veterinary Science, University of Bristol, Langford, Bristol BS40 5DU,  U.K.  2Department ofBiochemistry, University of Bristol , Bristol BS8 1TD, U.K.E-mail: E.Udovikova@Bristol.ac.ukIntroduction  Understanding the mechanisms that regulate the formation of subcutaneous and intramuscular fat (IF) Isimportant  in improving  meat quality.  Formation of IF is a process, which occurs in the later stages of development,perhaps due to age-related changes in expression of  lipogenic enzymes. Acetyl CoA carboxylase (ACC) and fatty acidsynthase (FAS) are the key enzymes in the process of  de novo synthesis of fatty acids. Delta-9-desaturase (d-9-d)  isanother key lipogenic enzyme, which catalyses conversion of saturated fatty acids (synthesised  de novo as well asdietary)  to  monounsaturated. The objective of the present research was to investigate the levels of ACC, FAS and d-9-d in the subcutaneous fat and muscles of pigs of different ages.Materials and methods  Thirty   Meishan x Large White  male  pigs were used in the study. Half  of the  animals hadbeen  castrated  at  birth  under  veterinary  supervision.  The  animals were  fed a  standard pelleted  feed  andslaughtered  at the age of  114,  144  and 174  days  (five boar and five castrated pigs per each age group). The  dietcontained 14 MJ/kg Digestible Energy, 170g/kg crude protein and 1.1g/kg lysine. Samples of subcutaneous fat and thelongissimus muscle were frozen in solid CO2  and  subsequently stored at –80 o C.  Cytosolic  and  microsomal fractionswere isolated by differential centrifugation. The levels of ACC and FAS in cytosol and the level of  d-9-d inmicrosomes  were  measured  by  Western  blotting using polyclonal sheep antibodies against   rabbit  mammary glandACC and FAC or rabbit polyclonal antibody against porcine d-9-d.  Significance of differences was assessed usingSudent’s t-test.Results  The levels of ACC, FAS and d-9-d  in      Table 1 Relative amount of  lipogenic enzymes (arbitrary units) insubcutaneous fat were low in 114d animals,  in-     subcutaneous fat and  longissimus  muscle of pigs of different  agecreased  at 144d  and significantly  declined  in        ------------------------------------------------------------------------------174d pigs (Table 1). In muscles d-9-d level was                                                   Age  (days)decreased between 114-144 days and then signi-      ------------------------------------------------------------------------------ficantly increased  in 174d animals. Thus,    the                                  114                       144                   174pattern of age-related changes of d-9-d in  mus-       ------------------------------------------------------------------------------cles showed the opposite trend to the pattern in                                                   Subcutaneous fatsubcutaneous fat. The levels of ACC and  FASin muscle were approximately  the  same in all              ACC         0.74 ± 0.17*        2.06 ±  0.21        0.71 ±  0.16***age groups. Castration led to an increase in the              FAS          0.88 ± 0.14*       1.67 ±  0.16        1.08 ±  0.13*d-9-d level in both tissues (Fig 1 and 2).                        D-9-d        18.7 ± 5.7*          54.6 ±  13.5        14.8 ±  7.9*Conclusions  The results suggest that the mecha-                                               Longissimus  musclenisms regulating expression of the lipogenic    en-zymes in subcutaneous fat and muscles are diffe-         ACC         0.77 ± 0.03            0.67 ± 0.01        0.58 ± 0.02rent. Sex hormones might be one of the  factors            FAS          0.10 ± 0.05            0.09 ± 0.04         0.06 ± 0.01regulating d-9-d expression.                                          D-9-d       10.3  ± 0.74*            6.7 ±  1.2           13.0±2.6*                                                                                     -----------------------------------------------------------------------------                                                                                     The data are presented as the mean ± SEM.                                                                                     * P<0.05 ,   ***P=0.001 (when  compared with  144d)0510152025B55C55B85C85B115C115delta-9-desaturase (arbitrary units)Figure 1. Effect of castration on d-9-d in musclesB=boar, C=castrate, 114,144,174=age (days)020406080100120140B55C55B85C85B115C115delta-9-desaturase (arbitrary units) Figure 2. Effect of castration on d-9-d insubcutaneous fat.B=boar, C=castrate,                114, 144, 174=age (days) Acknowledgements   This research was funded by DEFRAB    C                 B         C                 B        C114d                       144d                        174dB    C                    B         C                B        C114d                         144d                        174d

The effect of age on the level of lipogenic enzymes in subcutaneouse fat and muscle of pigs

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The effect of age on the level of lipogenic enzymes in subcutaneouse fat and muscle of pigs

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