Association of leptin genotype with growth performance, adipocyte cellularity, meat quality, and fatty acid profile in beef steers fed flaxseed or high-oleate sunflower seed diets with or without triticale dried distiller's grains.

Leptin genotypes can be identified as homozygous normal (CC), homozygous mutant (TT), and heterozygous (CT) based on a single-nucleotide polymorphism in exon 2 of the leptin gene, which has been associated with feed intake and fat deposition in cattle. The experiment was designed as 2 × 2 × 2 factorial with three main factors: (1) genotype (CT or TT) and diets fed 2) with or without triticale dried distiller's grains with solubles (DDG), and 3) with either flaxseed (FS) or high-oleate sunflower seed (SS). Evaluations included growth performance, subcutaneous fat deposition, adipocyte cellularity, meat quality, and fatty acid (FA) profile of various depots. Beef steers (n = 40, 459 ± 31 kg) of either CT or TT genotypes were housed in individual pens with ad libitum access to one of the four diets: 75% steam-rolled barley + 10% barley silage with 10% FS or SS (non-DDG diets, NDG) and 46.5% barley + 10% barley silage + 30% DDG, with 8.5% FS or SS, all on a dry matter basis. Growth performance, ultrasound subcutaneous fat thickness, rib eye area (REA), and plasma FA were measured prior to and during the finishing period. At slaughter, samples of subcutaneous fat, perirenal fat, and Longissimus thoracis (LT) muscle were collected for FA analysis and carcass and meat quality were measured. Compared with CT cattle, TT tended to have less (P = 0.06) C18:2-c9,t11 (rumenic acid) in plasma and subcutaneous fat and a greater proportion (P < 0.05) of C18:0 in subcutaneous, perirenal, and LT fat. Cattle with TT genotype also tended (P < 0.1) to have more total saturated and less unsaturated (USFA) and monounsaturated fats (MUFA) and had less (P = 0.04) linoleic acid in LT. Ultrasound fat thickness, REA, and average diameter of adipocytes in subcutaneous fat at 12 wk were not affected (P > 0.39) by genotype. Generally, carcass and meat quality were similar (P > 0.1) among diets, although adding FS tended to increase (P = 0.06) total USFA of subcutaneous fat including omega-3 FA (P < 0.001). For the high-fat diets evaluated, CT cattle would have more potential to produce beef with enhanced health benefits than would TT cattle.

Genetics, structure, and prevalence of FP967 (CDC Triffid) T-DNA in flax.

The detection of T-DNA from a genetically modified flaxseed line (FP967, formally CDC Triffid) in a shipment of Canadian flaxseed exported to Europe resulted in a large decrease in the amount of flax planted in Canada. The Canadian flaxseed industry undertook major changes to ensure the removal of FP967 from the supply chain. This study aimed to resolve the genetics and structure of the FP967 transfer DNA (T-DNA). The FP967 T-DNA is thought to be inserted in at single genomic locus. The junction between the T-DNA and genomic DNA consisted of two inverted Right Borders with no Left Border (LB) flanking genomic DNA sequences recovered. This information was used to develop an event-specific quantitative PCR (qPCR) assay. This assay and an existing assay specific to the T-DNA construct were used to determine the genetics and prevalence of the FP967 T-DNA. These data supported the hypothesis that the T-DNA is present at a single location in the genome. The FP967 T-DNA is present at a low level (between 0.01 and 0.1%) in breeder seed lots from 2009 and 2010. None of the 11,000 and 16,000 lines selected for advancement through the Flax Breeding Program in 2010 and 2011, respectively, tested positive for the FP967 T-DNA, however. Most of the FP967 T-DNA sequence was resolved via PCR cloning and next generation sequencing. A 3,720 bp duplication of an internal portion of the T-DNA (including a Right Border) was discovered between the flanking genomic DNA and the LB. An event-specific assay, SAT2-LB, was developed for the junction between this repeat and the LB.