• Fatty Acid Composition of New Zealand Forage Finished Beef Compared to US Grain Fed Beef

    Reciprocal Meat Conference Abstracts

    Fatty Acid Composition of New Zealand Forage Finished Beef Compared to US Grain Fed Beef

    Authors: , ,

Abstract

ObjectivesThe objective of this study was to evaluate differences in fatty acid (FA) composition of NZ beef finished on fodder beet (Beta vulgaris subsp. vulgaris L.; FB) or traditional grass diets and US grain-finished beef.Materials and MethodsStrip loins (n = 240) were selected from a commercial abattoir in NZ representing two feeding treatments (FB, non-FB) and expected low and high eating quality (primarily based on marbling) following a nationwide feeding trial to finish beef steers using FB. Selection resulted in four treatments: FB low quality (FBL), FB high quality (FBH), non-FB low quality (NFBL), and non-FB high quality (NFBH). Additionally, sides of beef (n = 120) representing USDA Top Choice (TCH) and Select (SEL) were sourced from a commercial abattoir in the US. Loins were fabricated prior to 21 d postmortem to isolate the longissimus lumborum (LL); these were sliced into 2.5 cm steaks, vacuum packaged, and stored at 2–4°C until 21 d or 35 d postmortem and frozen on the appropriate day. Lipids were extracted from a subset of samples via chloroform: methanol extraction then separated into polar and neutral fractions. Fatty acid methyl esters were evaluated using GC-FID. Data were analyzed with a 2-way ANOVA at a significance level of α = 0.05 and treatment, aging, and the respective interaction as fixed effects.ResultsAging influenced percent saturated FA (%SFA; P < 0.01), monounsaturated FA (%MUFA; P < 0.01), and polyunsaturated FA (%PUFA; P = 0.01). An increase in %MUFA and %PUFA at 35 d compared with 21 d (P < 0.01) corresponded with a decrease in %SFA at 35 d (P < 0.01). Treatment also influenced %PUFA (P < 0.01). NFBL contained the greatest %PUFA (P < 0.05). TCH and FBH contained less %PUFA than all treatments except SEL (P > 0.05). Treatment and aging also affected palmitic and stearic acids (P < 0.01), which make up the greatest portion of SFA. The proportion of palmitic acid was least in SEL (P < 0.05) and greater in FBH than NFBH and TC (P < 0.05). The US treatments had lower proportions of stearic acid than NZ treatments (P < 0.05). Both palmitic and stearic acids were of greater proportions in 35 d samples than 21 d samples (P < 0.05). Oleic acid contributes largely to total FA and was affected by the interaction of treatment and aging (P = 0.04). At 35 d, NZ treatments had greater proportions of oleic acid than at 21 d (P < 0.05). The proportion of oleic acid was least in SEL at both aging times. Of the PUFA, linoleic was affected by treatment (P < 0.05) and was greatest in SEL and TC (P < 0.05); FB treatments had the lowest proportion of linoleic acid (P < 0.05). Treatment and aging affected α-linolenic acid (P < 0.01). NFBL and NFBH had a greater proportion than both FB and US treatments (P < 0.05); both FB treatments had greater proportions of α-linolenic than US treatments (P < 0.05). Proportion of α-linolenic acid was elevated with 35 d aging (P < 0.05). Treatment affected proportions of long chain PUFA (P < 0.05) with TCH and SEL having lower proportions than NZ treatments (P < 0.05). Low quality NZ treatments had the greatest proportions of long chain PUFA (P < 0.05).ConclusionWhile finishing diet does affect fatty acid composition of beef strip steaks, finishing on FB produces a similar FA composition to non-FB grass. Total lipid content is also responsible for variation in FA composition. As lipids oxidize during aging, a shift toward more unsaturated FA occurs, leading to a decrease in %SFA.

Keywords: feeding, fatty acid, fodder beet

How to Cite:

Milopoulos J. T. & Garmyn A. J. & Miller M. F., (2019) “Fatty Acid Composition of New Zealand Forage Finished Beef Compared to US Grain Fed Beef”, Meat and Muscle Biology 3(2).

20 Views

5 Downloads

Published on
30 Nov 2019
Peer Reviewed