The effect of supplementing rumen undegradable unsaturated fatty acids on marbling in early-weaned steers1

Abstract

The objective of this study was to determine if supplementation with a rumen undegradable unsaturated fatty acids (FA) source improved marbling deposition in early-weaned steers. All steers (Angus, = 23; Angus × Hereford, = 24) were weaned at 150 ± 5 d of age. Steers were blocked by BW and breed and then randomly assigned to either control (CON; average 1.5 kg of corn gluten feed [CGF], = 23) or isocaloric supplementation containing a rumen undegradable fat source (RUF; 200 g of Megalac-R added to an average of 1.06 kg of CGF, = 24) offered 5 d/wk for 110 d. All steers had ad libitum access to pastures throughout treatment and received supplements individually. Steer BW and blood samples were collected at 0, 55, and 110 d of supplementation, and real-time ultrasound measurements were collected at d 110. Following treatment, steers were transported to Oklahoma State University for finishing and subsequent harvesting at a commercial plant. All data were analyzed using the PROC MIXED procedure of SAS either as repeated measures or ANOVA depending on parameters. There were no significant changes in BW from the beginning of treatment to harvest due to treatment. Ultrasound data showed that RUF steers tended ( = 0.08) to have more i.m. fat than CON at d 110. Serum concentrations of FA showed a treatment × day interaction ( < 0.02) for 16:0, 18:0, 18:1-9, 18:2, 20:4, and total FA. These specific FA concentrations slightly increased in CON steers, but there was a more pronounced increase in the concentration of these FA across the supplementation period in RUF steers. Serum triglyceride and cholesterol concentrations were increased ( < 0.01) on d 55 and 110 in RUF steers compared with those in CON steers. Serum leptin concentration in RUF steers was greater ( < 0.01) than CON steers at d 110. After harvest, RUF carcasses had greater ( = 0.01) marbling scores than those of CON carcasses. All other carcass measures were similar between treatments. The percentage of total lipids was increased ( = 0.011) in steaks from RUF compared to CON. There was a decrease ( < 0.05) in adipocyte diameter in i.m. fat depot of RUF steers compared to CON. There was also a tendency ( = 0.06) for RUF steers to have a greater percentage of 20 to 30 μm adipocytes in their i.m. depot than CON steers. This study indicates that supplementation of unsaturated FA can positively impact marbling deposition in early-weaned steers without impacting other carcass measures.

Review: Nutrigenomics of marbling and fatty acid profile in ruminant meat

“…In other studies, Cooke et al (2011) and Mangrum et al (2016) reported that animals receiving rumen undegradable unsaturated fatty acid, that contained a high percentage of oleic and linoleic acid, had greater intramuscular fat and marbling scores. On the other hand, Schoonmaker et al (2010) showed that animals fed wet distillers grains (rich in PUFA) had decreased marbling score.…”

The Effects of Age at Weaning and Length of Lipid Supplementation on Growth, Metabolites, and Marbling of Young Steers

“…Our lab has previously shown that early weaned steers fed an unsaturated RBL supplement during the growing phase and finished in a feedlot had increased marbling scores compared with those fed a control diet during the growing phase [ 10 ]. However, there is difficulty discerning between the effects of calf age and supplementation on growth and carcass characteristics.…”

“…This resulted in the reduced marbling scores compared to finished steers in other published papers. Steers fed a RBL during the growing phase and then finished in a feedlot had increased marbling scores compared with those fed a control diet during the growing phase and would have resulted in greater carcasses values [ 10 ]. Steers weaned at 7 months of age and supplemented with a protected fat source for a 28 days pre-conditioning period produced carcasses with increased marbling scores compared to those not supplemented [ 28 ].…”

“…Early weaning, removal of the calf from the dam prior to 180 days of age [ 4 ], has increased marbling content in beef carcasses compared with those weaned at the traditional 210 days of age because of the association of early weaning and concentrate feeding at a young age [ 5 , 6 , 7 , 8 , 9 ]. Supplementation of a rumen by-pass lipid (RBL) has also increased marbling in early weaned steers [ 10 ] and increased the amount of USFAs available for post-ruminal absorption by the small intestine [ 11 ]. Wang, et al [ 12 ] showed that pathways responsible for regulating intramuscular adipose deposition are active as early as 7 months of age.…”

Primer Seminario Técnico de Programación Fetal

“…El crecimiento postnatal a través de la hiperplasia de tejido adiposo depende de la ubicación anatómica, siendo más alto en el tejido intramuscular que perirrenal, omental o subcutánea. Por lo tanto, la nutrición postnatal temprana probablemente podría tener más efecto que la programación fetal en la adipogénesis intramuscular porque la ventana crítica de adipogénesis intramuscular es mayor después del parto (Bonnet et al, 2010;Du et al, 2013;Mangrum et al, 2016).…”