GENETIC INFLUENCE OF HOST ANIMAL ON FATTY ACID COMPOSITION IN BEEF CATTLE TISSUES

• Author / Creator

  Ekine-Dzivenu, Chinyere, C

• Beef fatty acid (FA) composition has emerged as a trait of economic importance as consumers have become more aware of the relationship between diet and health. As a result, they are paying more attention on the health impact of the food they consume including the type of dietary fat. Clinical studies have shown that the type of dietary fat has a more profound impact on human health than the amount of fat in the diet. In animal studies, phenotypic variations of fatty acid contents in animal tissues are commonly observed. The objectives of this study were: (1) to estimate heritabilities, genetic and phenotypic correlation for FAs in the brisket adipose tissue, and heritabilities for FAs in the subcutaneous adipose tissue (SQ) and longissimus lumborum (LL) muscle in beef cattle, (2): to estimate phenotypic and genetic correlations between FAs in the LL muscle with 6 carcass and 13 meat quality traits of economic importance, (3): to identify single nucleotide polymorphism markers (SNP) associated with FA composition in order to help in designing effective genetic selection tool / genotype based management program for selection of beef with healthier FA profile to meet consumers’ demands. Heritability for 15 individual and 10 groups of FAs having a concentration greater than 0.5% was estimated in the brisket adipose of 223 Angus based crossbred steers, and for over 80 individual and groups of FAs in the LL muscle and SQ adipose tissue of 1366 crossbred steers and heifers using a univariate animal model. Across the three tissues, heritability ranged from 0 for 7c-17:1 in the LL and 7c-17:1, 12t-18:1, 6t, 8t-18:2, 9t, 11t-18:2, n-6/n-3 in the SQ to 0.68 ± 0.1 for 9c-16:1 in the LL nuscle tissue. The result suggested the presence of host animal genetic effects on some FAs, including harmful 14:0 (0.61 ±0.13 )and 16:0 (0.54 ±0.1 ), beneficial MUFA (0.44±0.09), and health index (0.54±0.1) in the muscle. The results also showed that non-genetic factors played a major role in determining the concentration of many other FAs in the muscle including 9c, 11t-18:2 conjugated linoleic acid (CLA, 0.16 ±0.07) and vaccenic acid (18:1, trans-11, 0.24 ±0.08), which have been shown to benefit humam health. Phenotypic correlation between FAs in the brisket adipose tissue did not indicate significant antagonistic relationships between harmful and healthy FAs. The relationship revealed that reducing the concentration of harmful 16:0 would yield a correlated response of increased concentration of beneficial 9c-18:1, 11t-18:1, 9c,11t-18:2, and 18:3n3. However, in the LL muscle, genetic correlations revealed antagonistic relationships between monounsaturated FA (MUFA) and hot carcass weight (HCW) (-0.4±0.13) and between 18:3n3, 22:3n6, and total n-3 with marbling (MARB) (-0.82±0.11,-0.60±0.17, -0.84±0.11). For FAs and meat quality, unfavourable genetic relationships existed between 11t-18:1 with WBSF_29d, shear force on 26-day aged steaks and flavor (0.49±0.22, -0.37±0.32). There was also a moderate to strong antagonistic genetic relationship between beneficial polyunsaturated FAs, 9c, 11t-18:2, 18:3n3, 20:5n3, 22:6n3 and total omega 3 with meat quality traits particularly flavor, tenderness and juiciness. A two step bayesian analysis approach was used to evaluate the association of each of 15 individual and 10 grouped FAs for associations with 947 polymorphic SNP markers in 556 growth- and fat metabolism- related genes. The markers were developed and genotyped on 223 commercial crossbred beef steers that had FA profiles measured in brisket adipose tissue. The analyses identified 24 SNPs in 22 genes involved in various cellular processes were significantly associated with 8 FAs at a genome-wise threshold of P<0.05. Phenotypic variance explained by significant SNPs at genome-wide threshold for each of the 8 traits ranged from 0.0001% for MUFA with a heritability of 0.06±0.10 to 19.61% for cis-13-octadecenoic acid (13c-18:1) with a heritability of 0.43±0.1. The results show that FA concentrations in brisket adipose tissue of beef cattle are influenced by multiple genes, with different functional roles in the cell: several having small effects The results of the study will not only help us gain more insight into the genetic influence of host animals on FA composition in beef cattle tissues but also provide genetic parameters and DNA markers for more effective genetic evaluation and selection as well as DNA marker assisted diet management to improve FAs profiles in beef cattle.

• Subjects / Keywords

  • Fatty Acids
  • Genetic Influence
  • Beef Cattle

• Graduation date

  Spring 2015

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3PG1HW80

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.