3 research outputs found
Proteomic profiling of bovine M. longissimus lumborum from Crossbred Aberdeen Angus and Belgian Blue sired steers varying in genetic merit for carcass weight
Bovine skeletal muscle is a tissue
of significant value to the beef industry and global
economy. Proteomic analyses offer the opportunity to
detect molecular mechanisms regulating muscle growth
and intramuscular fat accumulation. The current study
aimed to investigate differences in protein abundance
in skeletal muscle tissue of cattle from two breeds of
contrasting maturity (early vs. late maturing), adiposity,
and muscle growth potential, namely, Belgian Blue
(BB) Ă— Holstein Friesian and Aberdeen Angus (AA) Ă—
Holstein Friesian. Twenty AA (n = 10) and BB (n = 10)
sired steers, the progeny of sires of either high or low
genetic merit, expressed as expected progeny difference
for carcass weight (EPDcwt), and bred through
AI, were evaluated as 4 genetic groups, BB-High,
BB-Low, AA-High, and AA-Low (n = 5 per treatment).
Chemical composition analysis of M. longissimus
lumborum showed greater protein and moisture and
decreased lipid concentrations for BB-sired compared
with AA-sired steers. To investigate the effects
of both sire breed and EPDcwt on M. longissimus
lumborum, proteomic analysis was performed using
2-dimensional difference gel electrophoresis followed by mass spectrometry. Proteins were identified from
their peptide sequences, using the National Center for
Biotechnology Information (NCBI) and Swiss-prot
databases. Metabolic enzymes involved in glycolysis
(glycogen phosphorylase, phosphoglycerate mutase)
and the citric acid cycle (aconitase 2, oxoglutarate
dehydrogenase) were increased in AA- vs. BB-sired
steers. Expression of proteins involved in cell structure,
such as myosin light chain isoforms and troponins I
and T, were also altered due to sire breed. Furthermore,
heat shock protein β-1 and peroxiredoxin 6, involved
in cell defense, had increased abundance in muscle of
AA-sired relative to BB-sired steers. Protein abundance
of glucose-6-phosphate isomerase, enolase-3, and
pyruvate kinase was greater in AA-sired animals of
High compared with Low EPDcwt. Changes in the
expression of these proteins were supported by gene
expression analysis using quantitative real-time PCR.
This information will aid in our understanding of
genetic infl uences controlling muscle growth and fat
accumulation and could contribute to future breeding
programs to increase lean tissue gain of beef cattle
Effect of dietary restriction and compensatory growth on performance, carcass characteristics, and metabolic hormone concentrations in Angus and Belgian Blue steers
peer-reviewedCompensatory growth (CG) is the ability of an animal to undergo accelerated growth after a period of restricted feeding. However, there is a dearth of information in relation to the effect of genotype on CG response, thus the objective of this study was to evaluate CG response in two contrasting breed types, namely Aberdeen Angus (AN) and Belgian Blue (BB). Crossbred ANÂ Ă—Â Holstein-Friesian or BBÂ Ă—Â Holstein-Friesian steers were assigned to one of two treatment groups in a two (genotypes)Â Ă—Â two (diets) factorial design. For 99Â days, one group (11 AN and 12 BB) was offered a high energy control diet (H-H) whereas the second group (11 AN and 12 BB) was offered an energy restricted diet (L-H). At the end of the differential feeding period (99Â days), both groups of animals were then offered a high energy control diet for a further 200Â days. All animals were then slaughtered on day-299 of the study. During feed restriction, L-H had lower DM intake (DMI), had greater feed conversion ratio (FCR) and lower plasma concentrations of insulin, IGF-1, leptin, glucose, urea, betahydroxybutyrate and smaller M. longissimus thoracis or lumborum muscle and fat depths compared to H-H steers. During realimentation, there was no difference in DMI between diets; however, L-H had greater live weight gain compared to H-H steers. Overall, H-H consumed greater quantities on a DM basis, however, had a higher FCR compared to L-H steers. By the end of the realimentation period, there was no difference in plasma metabolite or hormone concentrations, linear body measurements, ultrasonically scanned fat depths, carcass conformation, dressing percentage or fat class between H-H and L-H steers. At slaughter, carcass weights were affected by diet with greater values for H-H compared to L-H steers. Genotype affected measures associated with body composition including pelvic width and both muscle and fat depths (PÂ <Â 0.05). Overall, L-H had a CG (or recovery) index of 0.52 and did not make up for the loss of gains during the differential feeding period; however, M. longissimus thoracis et lumborum, a tissue of high economic value, recovered completely making it a target of interest for further investigation