Effects of feeding diets rich in α-linolenic acid and copper on performance, carcass characteristics, and fatty acid profiles of feedlot heifers1

Abstract

Our objective was to evaluate whether feeding elevated Cu concentrations in conjunction with Linpro, a co-extruded blend of field peas and flaxseed, affected in vitro fermentation, performance, and plasma lipid profiles of fattening beef heifers. In study 1, 2 in vitro trials were conducted as randomized complete experiments with a 2×2 factorial treatment arrangement (10 or 100 mg/kg added Cu and 0 or 10% Linpro, DM basis) to determine VFA/gas production and IVDMD. Linpro contains 12% α-linolenic acid and added vitamins and minerals. In study 2, a randomized complete block experiment with a 2×2 factorial treatment arrangement was conducted with the same previously described treatment. Crossbred yearling heifers (n=261; 351±23 kg initial BW) were blocked by weight into heavy and light groups and randomly assigned to experimental pens containing 10 or 11 heifers each. In study 1, no interactions between levels of Cu and Linpro were observed. Copper concentration did not affect IVDMD (P>0.2) but increased (P<0.05) by 1.2% when Linpro was included. Final pH was not effected by added Cu (P>0.05), but pH increased when Linpro was added (P<0.05). Total VFA were greater in high-Cu treatments (P=0.038) and molar proportions were not affected (P>0.34). Linpro had no effect on total VFA (P=0.46) and molar proportions of propionate and isobutyrate increased whereas acetate and the acetate:propionate ratio decreased (P<0.01). Linpro increased the production of H2S (30% higher; P=0.05), and Cu inclusion slightly increased CO2 proportion (64.06 vs. 67.58% for Linpro vs. Cu treatments, respectively). In study 2, there were no interactions between levels of Linpro and supplemental Cu except for plasma n-6:n-3 ratio (P<0.01). Final BW were similar for cattle fed 0 and 10% Linpro (581 vs. 588 kg; P>0.20), but cattle fed diets with Linpro consumed less feed (14.08 vs. 13.59 kg/d; P<0.05) and were therefore more efficient (0.129 vs. 0.137 for 0 vs. 10% Linpro, respectively; P<0.01). Carcass traits were not affected by treatment. Feeding elevated levels of Cu did not appreciably alter PUFA proportions in plasma and LM. Plasma and LM concentrations of omega-3 fatty acids, including C18:3, C20:5, and C22:5, were greater for heifers fed Linpro (P<0.05). Increasing dietary Cu was not effective as a strategy for decreasing ruminal biohydrogenation and subsequent tissue deposition of PUFA.

Revision of the currently authorised maximum copper content in complete feed

“…The above‐mentioned changes in lipid metabolism by copper supplementation (20–40 mg/kg DM) are published mainly by one research group (Engle and Spears, ; Engle et al., ,b,c); some recent studies in bulls found a decrease in cholesterol and an increase in the proportion of UFA in meat after supplementation of copper (30–40 mg/kg DM, background 4.7–7) (Correa et al., , ; Fagari‐Nobijari et al., ). On the other hand, these effects were not confirmed in Simmental steers (10 or 40 mg Cu/kg DM, background 5.1) (Engle and Spears, ), in feedlot Brangus bulls (40 mg Cu/kg DM, background 5.8) (Netto et al., ) and in beef heifers (16.8 and 98 mg Cu/kg DM complete diet) (Alvarado‐Gilis et al., ).…”

Transcriptomics and metabolomics analysis reveal the dietary copper deficiency and supplementation effects of liver gene expression and metabolite change in grazing sheep

“…Lipidomics analysis has revealed that palmitic acid impaired the development of hepatocellular carcinoma by regulating cell membrane fluidity and glucose metabolism [ 44 ]. Furthermore, research has demonstrated that adding Cu to the diet leads to higher concentrations of fatty acids in calf plasma [ 46 ]. This effect may be due to the crucial role of Cu in the activity of enzymes involved in fatty acid synthesis and metabolism.…”

Impacts of fat from ruminants' meat on cardiovascular health and possible strategies to alter its lipid composition

“…36 Efforts have been made to improve meat FA profile according to health recommendations leading to meat products with reduced SFA and cholesterol and improved contents of MUFA, n-3 or CLA. For example, feeding beef cattle with rumen-protected fish oil supplements 37 or oil seeds 38 can be used to increase C20:5n-3 and C22:6n-3 concentrations. Also, there have been efforts to modulate the genetics of bovines to increase total n-3 FA: Cheng et al 39 demonstrated that the codon-optimized C. elegans mfat1 gene can be functionally expressed in beef cattle and converts n-6 PUFAs to n-3 PUFAs.…”