Red blood cells are superior to plasma for predicting subcutaneous trans fatty acid composition in beef heifers

The trans (t)-18:1 content in beef has become more of interest as partially hydrogenated vegetable oils are removed from foods. Predicting t-18:1 early in the feeding period would be useful if limitations are put on t-18:1 in beef. To determine which blood component is better related to backfat, proportions of t10-18:1 and t11-18:1 (vaccenic acid) were measured in heifer red blood cells (RBC) and plasma (N = 14) after 0, 28, 56, and 76 d on a barley-grain-based diet, and correlated with post-slaughter subcutaneous fat (SCF). Total t-18:1 declined in both RBC and plasma during late finishing (P < 0.05). At 28 d, t11-18:1 decreased and t10-18:1 increased in RBC and plasma (P < 0.05). By 76 d, t10-18:1 declined to 0 d levels. RBC and plasma t-18:1 compositions were highly correlated (t10-18:1, r ≥ 0.7, P ≤ 0.02; t11-18:1, r ≥ 0.51, P ≤ 0.06). Correlations with post-slaughter backfat were, however, consistently greater for RBC compared with plasma. The use of RBC t-18:1 composition may, therefore, be superior to plasma for predicting t-18:1 in SCF, and the length of finishing could be useful for manipulating t-18:1 in beef. The time required for changes in t18:1 in RBC to reflect in changes in SCF still, however, needs to be determined to establish optimal durations for beneficial modification.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Beef Quality of Calf-Fed Steers Finished on Varying Levels of Corn-Based Wet Distillers Grains Plus Solubles

Ninety-four, calf-fed crossbred steers were randomly allocated to three different dietary treatments (0%, 15% or 30% wet distillers grains plus solubles - WDGS – DM basis) and fed for 167 d to test the influence of different levels of WDGS on quality attributes of beef. At 48 h postmortem, marbling score, marbling texture, and marbling distribution were assessed by a USDA grader. After grading, one ribeye slice (Longissimus thoracis) about 7 mm thick was excised from each carcass, trimmed of subcutaneous fat, and analyzed for fatty acid profile and lipid content. At 7 d postmortem, 48 top blades (Infraspinatus), strip loins (Longissimus lumborum) and tenderloins (Poas major) (16 per treatment) were removed from shoulder clods and short loins and two steaks were obtained for measurement of mineral content, fatty acid profile (except strip loins), trained sensory analysis, objective color and lipid oxidation. Finishing diet did not influence the content of total lipid (P = 0.19) or marbling, marbling texture, or marbling distribution (P = 0.46, P = 0.84 and P = 0.40, respectively). Feeding WDGS created a linear increase (P \u3c 0.01) of PUFA in all three muscles (Longissimus thoracis showed: 4.90, 5.91, and 6.23 % for 0, 15 and 30%, respectively). Similar responses were observed for 18:2(n-6) and total omega 6 fatty acids. Conversely, lower proportions of 18:1(n-7) fatty acid were observed in beef from animals fed 30% WDGS (P \u3c 0.01). Total trans fatty acids increased linearly in strip loin and top blade steaks (P \u3c 0.01) whereas proportions of 16:0 and 14:1(n-5) fatty acids decreased in all muscles (P \u3c 0.01) as levels of WDGS increased. Diet did not affect mineral content of top blades or strip loins. For tenderloin steaks, sulfur concentration was lower when 30% of WDGS was fed (P = 0.05). No effects on sensory attributes and Warner Bratzler shear force were observed (P ≥ 0.50), except a minimal effect on strip loin juiciness (5.32, 4.86, and 5.52 for 0, 15, and 30%, respectively; P = 0.02). Top blade and tenderloin steaks from cattle fed 30% WDGS were significantly less red (lower a* values) on day 3 of simulated retail display (P \u3c 0.04). Inclusion of 30% WDGS in the diet resulted in higher levels of oxidation after 7 d of retail display for top blade and strip loin steaks (P \u3c 0.01). Feeding WDGS to calf-fed steers altered fatty acid profile, increased oxidation and decreased color stability during retail display

Effects of dietary flaxseed and vitamin E on fermentation, nutrient disappearance, fatty acid biohydrogenation, and microbial protein synthesis using a simulated rumen (Rusitec)

Two simulated rumens (Rusitecs) were used to assess the effects of flaxseed (FS) and (or) vitamin E (VE) on rumen fermentation, fatty acid (FA) biohydrogenation, and microbial protein synthesis. Ground FS replaced 0% or 15% of barley grain, along with VE at 0 or 1000 IU d−1 in a 2 × 2 factorial experiment. Flaxseed lowered neutral detergent fiber (P = 0.001) and acid detergent fiber (P = 0.01) and increased (P = 0.001) nitrogen (N) disappearance. Flaxseed also increased (P = 0.01) total volatile FA and decreased (P = 0.001) acetate production. When both FS and VE were included, the acetate:propionate ratio decreased (P = 0.04). Biohydrogenation of FA was not influenced by VE, but total FA and C18:0 in effluent were increased (P = 0.001) and C16:0 decreased (P = 0.001) by FS. With VE, total microbial N (MN) was increased (P = 0.001). In the concentrate, production of MN in feed-particle-bound bacteria was increased (P = 0.001) by VE. Vitamin E did not alter FA biohydrogenation but did promote MN production. The stable and relatively high pH in the Rusitec may have prevented the typical shift from C18:1 trans-11 to C18:1 trans-10 with concentrate diets. Future studies simulating subclinical acidosis in the Rusitec may illuminate ruminal mode(s) of action of VE on FA biohydrogenation.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Comparative effects of feeding citrus pulp and grape pomace on nutrient digestibility and utilization in steers

© 2020 Feedlot beef production in tropics and subtropics is being limited by shortage of feed ingredients due to prolonged droughts resulting in high prices of cereal grains and reduced profitability. To alleviate feed shortages and increase profitability for the feedlot industry, it is important to explore underutilized non-conventional resources such as fruit by-products. The current study compared the nutrient intake, digestibility and utilization effects of feeding either 150 g/kg of dried citrus pulp (DCP) or grape pomace (DGP) as alternative dietary fibre sources to 7 months-old Angus steers (281 ± 15.7 kg) under feedlot conditions. Twenty-four steers were assigned to three dietary treatments (8 steers/treatment) in a completely randomised design. Each steer was treated as an experimental unit. Steers were adapted to diets for 21 d followed by 7 d of sample collection during which nutrient intake, digestibility, rumen fermentation parameters, nitrogen retention and microbial N supply were determined. All the data were analysed using the GLIMMIX procedures. Overall, steers fed DGP had the greatest dry matter intake (DM), organic matter (OM) crude protein (CP), ash free neutral detergent fibre (aNDFom), ether extract (EE) and starch intake followed by DCP and control (CON) diets (P ≤. 05). Apparent digestibilities of DM, OM and aNDFom were higher (P ≤. 05) for DCP diet compared to DGP and CON diets. Feeding DCP and DGP diets increased ruminal concentrations of total volatile fatty acids, acetate and isovalerate, and acetate to propionate ratio, and reduced propionate concentrations compared to the CON diet (P ≤. 05). The steers fed the CON diet had the greatest urinary excretions of allantoin, uric acid and total purine derivatives followed by those fed the DCP and DGP diets (P ≤. 05). Nitrogen intake, faecal nitrogen (N), N retention and N efficiency utilization were in the order of DGP > DCP > CON diets (P ≤. 05). Overall, feeding DGP as alternative fibre source to wheat bran improved nutrient intake, retention and efficiency of N utilization but reduced apparent nutrient digestibility compared to DCP. Current finding suggests that DGP may be a better fibre substitute for wheat bran in beef diets than DCP