ABSTRACT
Beef is a source of essential fatty acids (EFA), linoleic (LA) and alpha-linolenic (ALA) acids, which protect against inflammatory and cardiovascular diseases in humans. However, the intramuscular EFA profile in cattle is a complex and polygenic trait. Thus, this study aimed to identify potential regulatory genes of the essential fatty acid profile in Longissimus thoracis of Nellore cattle finished in feedlot. Forty-four young bulls clustered in four groups of fifteen animals with extreme values for each FA were evaluated through differentially expressed genes (DEG) analysis and two co-expression methodologies (WGCNA and PCIT). We highlight the ECHS1, IVD, ASB5, and ERLIN1 genes and the TF NFIA, indicated in both FA. Moreover, we associate the NFYA, NFYB, PPARG, FASN, and FADS2 genes with LA, and the RORA and ELOVL5 genes with ALA. Furthermore, the functional enrichment analysis points out several terms related to FA metabolism. These findings contribute to our understanding of the genetic mechanisms underlying the beef EFA profile in Nellore cattle finished in feedlot.
ABSTRACT
The beef fatty acid (FA) profile has the potential to impact human health, and displays polygenic and complex features. This study aimed to identify the transcriptomic FA profile in the longissimus thoracis muscle in Nellore beef cattle finished in feedlot. Forty-four young bulls were sampled to assess the beef FA profile by considering 14 phenotypes and including differentially expressed genes (DEG), co-expressed (COE), and differentially co-expressed genes (DCO) analyses. All samples (n = 44) were used for COE analysis, whereas 30 samples with extreme phenotypes for the beef FA profile were used for DEG and DCO. A total of 912 DEG were identified, and the polyunsaturated (n = 563) and unsaturated ω-3 (n = 346) FA sums groups were the most frequently observed. The COE analyses identified three modules, of which the blue module (n = 1776) was correlated with eight of 14 FA phenotypes. Also, 759 DCO genes were listed, and the oleic acid (n = 358) and monounsaturated fatty acids sum (n = 120) were the most frequent. Furthermore, 243 and 13, 319 and seven, and 173 and 12 gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways were enriched respectively for the DEG, COE, and DCO analyses. Combining the results, we highlight the unexplored GIPC2, ASB5, and PPP5C genes in cattle. Besides LIPE and INSIG2 genes in COE modules, the ACSL3, ECI1, DECR2, FITM1, and SDHB genes were signaled in at least two analyses. These findings contribute to understand the genetic mechanisms underlying the beef FA profile in Nellore beef cattle finished in feedlot.
Subject(s)
Fatty Acids , Transcriptome , Animals , Cattle/genetics , Fatty Acids/analysis , Male , Meat/analysis , Muscle, Skeletal/metabolism , PhenotypeABSTRACT
Dental classification of carcasses is used as a parameter of cattle maturity at slaughter, and it can influence carcass and meat quality traits. Brazilian beef-packing companies use the number of permanent incisor (PI) teeth as a parameter for bonus and certification of carcasses with superior quality. However, when non-castrated male such as F1 Angus-Nellore (Bos taurus×Bos indicus) are slaughtered, only animals without PI teeth are subsidized by the breed association. We evaluated these animals finished in feedlot for 180 days with zero versus two PI teeth on the carcass and meat quality traits. At the time of slaughter, 88 carcasses were selected, forming two treatments according to dental carcass maturity (0 versus 2 PI teeth; 44 animals per category). It was demonstrated that the number of PI teeth (0 versus 2 PI) did not influence (p>0.05) carcass (weights, yield, cooling loss, ribeye area and the backfat thickness) and meat quality traits (Longissimus thoracis chemical composition, color, cooking losses, shear force and pH). Thus, dental carcass maturity (zero versus two PI teeth) does not influence non-castrated male F1 Angus-Nellore finished in feedlot for 180 days. This is the first study to demonstrate that carcasses of non-castrated male F1 Angus-Nellore with two PI teeth should be subsidized in a similar way to those with zero PI teeth. Moreover, Brazilian beef-packing companies could produce heavier and leaner carcasses of acceptable quality though the use of crossbred cattle such as non-castrated F1 Angus Nellore.
