Phenotypic and genetic relationships of residual feed intake measures and their component traits with fatty acid composition in subcutaneous adipose of beef cattle

Citation

Zhang, F., Ekine-Dzivenu, C., Vinsky, M., Basarab, J.A., Aalhus, J.L., Dugan, M.E.R., Li, C. (2017). Phenotypic and genetic relationships of residual feed intake measures and their component traits with fatty acid composition in subcutaneous adipose of beef cattle. Journal of Animal Science, [online] 95(7), 2813-2824. http://dx.doi.org/10.2527/jas2017.1451

Plain language summary

Feed efficiency is of particular interest to the beef industry as feed is the largest variable cost in production while fatty acid composition is also emerging as an important trait, due to the potential implications of dietary fatty acids on human health. Selection of more efficient cattle will reduce beef production costs but its possible impacts on end-product quality such as carcass and meat quality traits including fatty acid composition must also be investigated. The purpose of this study was to evaluate how selection of feed efficiency traits will lead to changes of fatty acid composition in subcutaneous adipose tissue of beef cattle based on measures of feed efficiency and fatty acids in 1366 finishing steers and heifers. The results showed that selection for more efficient beef cattle will result in a healthier fatty acid profile by lowering the content of omega-6 polyunsaturated fatty acids, thus reducing the ratio of omega-6 to omega-3, along with increasing the amount of palmitoleic acid (9c-16:1). Moreover, selection of beef cattle with lower feed intake will also improve fatty acid profiles by increasing amount of myristoleic acid (9c-14:1) and total conjugated linoleic acids (CLA) in the adipose tissue. However, selection of beef cattle with a better growth rate will decrease the content of healthy fatty acids vaccenic acid (11t-18:1) and total CLA. Therefore, it is recommended that a multiple trait selection approach or index be used when genetic improvements of fatty acid composition, feed efficiency, feed intake and growth are important in the breeding goal. The research result will also provide a value reference of genetic parameters on both feed efficiency measures and fatty acid composition for the beef industry to construct a multiple trait selection index for selection of more efficient cattle with improved fatty acid profile in beef.

Abstract

Feed efficiency is of particular interest to the beef industry because feed is the largest variable cost in production and fatty acid composition is emerging as an important trait, both economically and socially, due to the potential implications of dietary fatty acids on human health. Quantifying correlations between feed efficiency and fatty acid composition will contribute to construction of optimal multiple-trait selection indexes to maximize beef production profitability. In the present study, we estimated phenotypic and genetic correlations of feed efficiency measures including residual feed intake (RFI), RFI adjusted for final ultrasound backfat thickness (RFIf); their component traits ADG, DMI, and metabolic BW; and final ultrasound backfat thickness measured at the end of feedlot test with 25 major fatty acids in the subcutaneous adipose tissues of 1,366 finishing steers and heifers using bivariate animal models. The phenotypic correlations of RFI and RFIf with the 25 individual and grouped fatty acid traits were generally low (<0.25 in magnitude). However, relatively stronger genetic correlation coefficients of RFI and RFIf with PUFA traits including the n-6:n-3 ratio (0.52 ± 0.29 and 0.45 ± 0.31, respectively), 18:2n-6 (0.45 ± 0.18 and 0.40 ± 0.19, respectively), n-6 (0.43 ± 0.18 and 0.38 ± 0.19, respectively), PUFA (0.42 ± 0.18 and 0.36 ± 0.20, respectively), and 9c-16:1 (−0.43 ± 0.20 and −0.33 ± 0.22, respectively) were observedHence, selection for low-RFI or more efficient beecattle will improve fatty acid profiles by lowering the content of n-6 PUFA, thus reducing the ratio of n-6 to n-3 along with increasing the amount of 9c-16:1Moderate to moderately high genetic correlations were also observed for DMI with 9c-14:1 (−0.32 ± 0.17) and the sum of CLA analyzed (SumCLA; −0.45 ± 0.21)suggesting that selection of beef cattle with lower DMwill lead to an increase amount of 9c-14:1 and SumCLA in the subcutaneous adipose tissue. However, unfavorable genetic correlations were detected for ADG with 11t-18:1 (−0.38 ± 0.23) and SumCLA (−0.73 ± 0.26)implying that selection of beef cattle with a bettegrowth rate will decrease the contents of healthy fatty acids 11t-18:1 and SumCLA. Therefore, it is recommended that a multiple-trait selection index be used when genetic improvements of fatty acid composition, feed efficiency, feed intake, and growth are important in the breeding objective.

Publication date

2017-01-01

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