Effect of supplementation of beef steer diets with oil containing n6 and n3 fatty acids and 48h feed withdrawal treatments on animal productivity, carcass characteristics and fatty acid composition

Effects of n-3 and n-6 feeding sources on the quality and lipid oxidation of meat from feedlot-finished Bos indicus steers

This study was conducted to evaluate the fatty acid profile, sensory properties and lipid oxidation of meat on retail display (RD) from Nellore steers (n = 96) fed diets containing soybean (SOY), sunflower (SUN), or linseed (LIN) oil or a control diet (CON). After slaughtering, samples of the Longissimus muscle were collected for sensory properties (1 day), fatty acid composition (1 day) and oxidation stability (3 days under RDC) evaluations. No differences in total lipids, cholesterol, TBARS, and total SFAs, MUFAs, PUFAs, and PUFA/SFA were observed. However, meat from animals fed vegetable oil had more CLA than that of the CON samples. The flavour, juiciness and overall acceptability were affected by the treatments (P < 0.05), but no consistent effect of a specific oil source was observed. Meat colour was not affected by diets or days under RD, and 7-ketocholesterol was not detected in any sample. The oil sources used in this work were not effective in consistently changing meat properties.

Adding heat-treated rapeseed to the diet of yak improves growth performance and tenderness and nutritional quality of the meat

Heat-treated rapeseed was supplemented to indoor fed yaks in winter to test the effect on dry matter intake (DMI), body mass change, and meat quality. Sixteen 3-year-old yak steers (124 ± 15.3 kg) were divided randomly into two groups and were offered either heat-treated rapeseed (HTR) or rapeseed meal (CONT). The yaks were allowed 14 days for adjustment and measurements were made over 120 d. There was no difference in DMI between groups (p = 0.67), but average daily gain tended to be higher (p < 0.056) and feed to gain ratio tended to be lower (p = 0.050) in HTR than in CONT yaks. Meat from HTR yaks was more tender (p = 0.006), had higher intramuscular fat (p = 0.013), and had lower cholesterol content (p = 0.009) than from CONT yaks. In addition, the atherogenic index was lower (0.37 vs. 0.43; p = 0.049), the PUFA:SFA ratio was higher (0.55 vs. 0.37; p = 0.049), and the n-6:n-3 (n-6 PUFA to n-3 PUFA) ratio was lower (2.76 vs. 4.78; p = 0.003) in HTR than in CONT yaks, which all favoured the HTR yaks. Meat from HTR yaks met human health standards of a PUFA:SFA ratio of above 0.4 and n-6:n-3 ratio of less than 4, whereas meat from CONT yaks just missed these standards.

Preadipocyte and adipose tissue differentiation in meat animals: influence of species and anatomical location

Early in porcine adipose tissue development, the stromal-vascular (SV) elements control and dictate the extent of adipogenesis in a depot-dependent manner. The vasculature and collagen matrix differentiate before overt adipocyte differentiation. In the fetal pig, subcutaneous (SQ) layer development is predictive of adipocyte development, as the outer, middle, and inner layers of dorsal SQ adipose tissue develop and maintain layered morphology throughout postnatal growth of SQ adipose tissue. Bovine and ovine fetuses contain brown adipose tissue but SQ white adipose tissue is poorly developed structurally. Fetal adipose tissue differentiation is associated with the precocious expression of several genes encoding secreted factors and key transcription factors like peroxisome proliferator activated receptor (PPAR)γ and CCAAT/-enhancer-binding protein. Identification of adipocyte-associated genes differentially expressed by age, depot, and species in vivo and in vitro has been achieved using single-gene analysis, microarrays, suppressive subtraction hybridization, and next-generation sequencing applications. Gene polymorphisms in PPARγ, cathepsins, and uncoupling protein 3 have been associated with back fat accumulation. Genome scans have mapped several quantitative trait loci (QTL) predictive of adipose tissue-deposition phenotypes in cattle and pigs.

Effect of supplementing different oils: linseed, sunflower and soybean, on animal performance, carcass characteristics, meat quality and fatty acid profile of veal from "Rubia Gallega" calves

The fatty acid (FA) composition of longisimus dorsi (LD) and subcutaneous fat (SCF) from Rubia Gallega (RG) calves was compared for three dietary oil sources (linseed, LO; sunflower, SFO or soybean, SYO). Oils were added (4.5%) to a commercial concentrate and no differences on animal performance, carcass characteristics or meat quality among diets were noted. Total n-3 polyunsaturated FA (PUFA) increased in LD and SCF when feeding LO diet (P<0.001). The trans(t) FA profiles were dominated by t11-18:1, except when feeding SFO diet, where ∑t6- to t10-18:1 exceeded t11-18:1 leading the highest (∑t6-to t10-18:1)/t11-18:11 ratio in LD (P<0.05). The overall changes in n-3 PUFA and t18:1 when feeding LO and SYO could be viewed as positive for human health, but quantitatively it was apparent that most dietary PUFA were completely biohydrogenated. Inhibiting PUFA biohydrogenation will be an important next step to improve the FA composition of RG cattle.

Fatty Acid Composition of Phospholipids and in the Central and External Positions of Triacylglycerol in Muscle and Subcutaneous Fat of Beef Steers Fed Diets Supplemented with Oil Containing n6 and n3 Fatty Acids While Undergoing One of Three 48 h Feed Withdrawal Treatments

This study was designed to determine the effects of dietary oil and feed withdrawal treatments on fatty acid composition of phospholipids of triacylglycerol in pars costalis diaphragmatis muscle and subcutaneous fat from the brisket. A 2 × 3 factorial experiment was conducted with crossbred steers with an initial body weight of 280.5 ± 5.8 kg. Steers were fed either a control or an oil containing diet where 5% of the control diet was replaced with an equal mixture sunflower and flax oil while undergoing one of three feed withdrawal treatments: no withdrawal, a single 48 h withdrawal before initiation of fattening at one year of age, or 48 h withdrawal at 8 wk intervals from weaning to initiation of fattening. At time of processing samples of muscle and fat were obtained and analyzed to determine fatty acid composition. Disproportionate distribution of the fatty acids was observed by diet, feed withdrawal regimen and whether the sample was from muscle or fat. Differences are discussed in detail, and our data suggests a special function for the fatty acids that accumulate in specific positions of the triacylglycerol due to treatment.