Does growth path influence beef lipid deposition and fatty acid composition?

Area of Science:

• Animal Science
• Nutritional Biochemistry
• Molecular Biology

Background:

• Understanding skeletal muscle adaptations to compensatory growth is crucial for optimizing meat quality.
• Lipid metabolism plays a significant role in the sensory and nutritional traits of meat.
• Gene expression studies in cattle are needed to elucidate these adaptations.

Purpose of the Study:

• To investigate the effects of discontinuous growth (feed restriction followed by re-alimentation) on lipid metabolism in Alentejana bulls.
• To analyze changes in fatty acid composition and gene expression of adipogenic and lipogenic pathways in skeletal muscle.
• To identify key genes involved in skeletal muscle adaptation during compensatory growth.

Main Methods:

• Forty young Alentejana bulls were divided into ad libitum fed (CG) and discontinuous growth (DG) groups.
• DG group underwent feed restriction from 9 to 15 months, followed by ad libitum feeding until 24 months.
• Intramuscular fat, total fatty acids, minor/major fatty acid profiles, and gene expression (microarray and qRT-PCR) were analyzed.

Main Results:

• Intramuscular fat and total fatty acid content were similar between groups, but specific fatty acid profiles differed.
• DG bulls showed higher proportions of certain minor fatty acids (e.g., 17:1c9, 18:1t9) and lower branched-chain fatty acids.
• Compensatory growth down-regulated ACACB, FABP3, HADHA, and SLC37A4 gene expression, while up-regulating ELOVL5 and FASN expression compared to continuous growth.

Conclusions:

• Discontinuous growth significantly alters fatty acid profiles and gene expression in cattle skeletal muscle.
• Specific genes involved in lipid metabolism are differentially regulated by compensatory growth strategies.
• These findings contribute to understanding the molecular mechanisms of meat quality development in Mediterranean cattle breeds.