40 young Alentejana bulls were either fed hay and concentrates ad libitum (CG group) until 18 months of age or subject to food restriction from 9 to 15 months of ...
A.S.H. Costa2, P. Costa2*, S. P. Alves2, C. P. M. Alfaia2, J. A. Simões1, Paula Lopes2, J. F. Hocquette3, C. R. Calkins4, and R. J. B. Bessa1,2
1L-INIAV
Santarém, Instituto Nacional dos Recursos Biológicos, Quinta da Fonte Boa, 2005-048 Vale de Santarém - Faculdade de Medicina Veterinária, Universida de Lisboa, Avenida da Universidade Técnica, Pólo Universitário do Alto da Ajuda, 1300-477 Lisboa, Portugal. UR 1213, Unité de Recherches sur les Herbivores (URH), Theix, F-63122 Saint-Genés Champanelle, France. 4University of Nebraska, Department of Animal Science, Lincoln, Nebraska, USA1A contribution of the University of Nebraska Agricultural Research Division, Lincoln, NE 68583. 2CIISA
3INRA,
Conclusions
Aims Take advantage of the recent progress in genomics to acquire a better knowledge of the biochemical traits and the genes dictating bovine
meat quality.
To investigate the effects of the growth path on gene expression and beef
fatty acid composition.
Background
The results from the present study show that compensatory growth impacts on fatty acid deposition through enhanced fatty acid synthesis and elongation. Lipid
metabolism is affected by growth path to
a transcriptional and molecular level, with beneficial effects on the nutritional quality of meat obtained.
Results and discussion
Discontinuous growth doesn’t impact negatively on IMF deposition
An alternative to these intensive finishing systems is the traditional Mediterranean system in which young bulls are feed-restricted in summer when pasture availability is scarce, and are fed pasture ad libitum during the spring, when grass availability and quality increase [1]. This strategy take advantage of the compensatory growth. In spite of the recent advances in transcriptomics, there is still a shortage of gene expression studies addressing the adaptations in skeletal muscle of cattle in response to compensatory growth, particularly regarding lipid metabolism.
IMF (g/100 g meat)
2,5
Similar levels of intramuscular fat (IMF) were observed in the meats of continuous (CG) and discontinuous growth (DG) groups
2,0 1,5 1,0 0,5 0,0
CG
DG
Growth path impacts on meat fatty acid composition 50
**
45
Feed restricted bulls deposit lower proportions of saturated (SFA) and branched chain fatty acids (BCFA)
Fatty acid partial sums (mol%)
Experimental design
40 young Alentejana bulls were either fed hay and concentrates ad libitum (CG group) until 18 months of age or subject to food restriction from 9 to 15 months of age (only hay was provided), and fed hay and concentrates ad libitum until 24 months of age (DG group).
40 35 30 25
CG DG
Increased 18:1-t10
20 15 10
**
5 0
SFA
Alentejana bulls (n=40)
cisMUFA
TFA
* BCFA
PUFA
n-3 PUFA
Compensatory growth enhances fatty acid desaturation
Material and methods Meat samples were lyophilised to constant weight. The IMF in lyophilised samples was extracted, converted to fatty acid methyl esters and analysed as described by Jerónimo et al. [2]. A new cDNA chip was developed by the INRA to access the expression of more than 3000 genes or bovine EST sequences related to growth, carcass fatness and beef quality including connective tissues, proteolytic activity, metabolic enzymes. Total RNA was amplified and labelled with Cyanine 3 using Agilent’s Low RNA Input Linear Amplification Kit, PLUS, One-Color (Agilent Technologies) following the detailed protocol described by Hocquette et al. [3]. Fatty acid composition Gas Cromatography
Gene expression
microarray
80
Acknowledgements Abattoir staff for their cooperation in carcass collection data and meat sampling Unidade de Produção Animal, Instituto Nacional de Investigação Agrária e Veterinária (INIAV)staff for assistance in animal management PTDC/CVT/111744/2009 grant individual fellowships SFRH/BD/2009/61068 and SFRH/BPD/2008/46135
60
***
50 40 30 20 0
*
*
10 ID14
ID16
ID17
ID18
CG DG
n-6 PUFA
Significance level: *, P
