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Sirvi Autor "Plavina, S." järgi

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  • Pisipilt
    Kirje
    IGF1 and IGF2 gene polymorphisms are associated with the feed efficiency of fattened lambs in Latvian sheep breads
    (Estonian University of Life Sciences, 2024) Trapina, I.; Plavina, S.; Krasņevska, N.; Paramonovs, J.; Kairisa, D.; Paramonova, N.
    Feed efficiency is an economically important indicator in sheep farming. The most effective technology for selecting the best feed-efficient lambs for breeding is marker association selection of genetic variations in the sheep genome as potential biomarkers. In tissue growth and differentiation, insulin-like growth factors (IGFs) play a major role: IGF1 mediates the effects of growth hormone, and IGF2 is a growth regulator, regulating skeletal muscle growth. The study aims to find possible molecular markers for feed efficiency indicators in IGF1 and IGF2 genes for Latvian sheep breeds. The exonic regions of the IGF1 and IGF2 genes were sequenced for the first time in the genomic DNA of 76 controlled, intensively fattened lambs, to search for possible genetic biomarkers. Seven polymorphic loci in the IGF1 gene and sixteen in the IGF2 gene were detected. Statistically significant associations of the IGF1 SNP rs600896367 were found with residual indicators: Residual feed intake, Residual weight gain (RWG), and Residual intake and body weight gain (RIG), and with feed efficiency and feed conversion ratio in the overall group of samples. Additionally, IGF2 SNPs New_7 and rs429576107 exhibited associations with RWG and RIG specifically in the Latvian dark-head sheep group. On average, effect of the IGF1 SNP on associated feed efficiency residuals is 3.9%, with the most pronounced impact observed in RFI. In contrast, the influence of IGF2 SNPs is comparatively lower. Our results indicate that rs600896367 and New7/rs429576107 are potential molecular markers for marker-assisted selection in sheep breeding for residual feed efficiency indicators.
  • Pisipilt
    Kirje
    Metabolic hormone profiles pre- and post-fattening in sheep breeds in Latvia with varying feed efficiency
    (Estonian University of Life Sciences, 2025) Trapina, I.; Plavina, S.; Krasņevska, N.; Paramonovs, J.; Kairisa, D.; Paramonova, N.
    In sheep production, livestock fattening constitutes a major source of income, with overall economic efficiency largely determined by feed efficiency (Fe). Feed efficiency, in turn, is influenced by the hormone-regulated physiological state of the animal. Monitoring hormone levels as biomarkers can significantly optimise the lamb fattening process, improving outcomes. The study aims to analyse levels of hormone IGF-1, insulin, total T4, ACTH, haematocrit (HCT), haemoglobin (Hb), and glucose in sheep breeds raised in Latvia at different ages or fattening periods and corresponding Fe indicators. Blood samples and phenotypic data were collected from 76 and 92 intensively fattened lambs at ~81 and ~150 days of age, respectively, with ~60% representing the Latvian Dark-Head breed. Post-fattening levels of IGF-1, insulin, haematocrit, and haemoglobin were statistically higher, while glucose was elevated pre-fattening. IGF-1 and insulin varied significantly across five and three breeds; HCT and Hb levels differed significantly in one breed each. Pre-fattening IGF-1 and glucose levels correlated with feed efficiency traits. Regression analysis showed that pre-fattening hormone levels explained 24.7% of FCR, 22.8% of RGR, and 31.6% of KR variance. Results demonstrate breed-specific hormonal differences in Latvian sheep and indicate the potential of hormone levels as biomarkers for assessing and optimising feed efficiency, emphasizing the need to study hormone levels across breeds and at different fattening stages.
  • Pisipilt
    Kirje
    MSTN gene polymorphisms are associated with the feed efficiency of fattened lambs in Latvian sheep breeds
    (Estonian University of Life Sciences, 2024) Trapina, I.; Plavina, S.; Krasņevska, N.; Paramonovs, J.; Kairisa, D.; Paramonova, N.
    The economic benefit for sheep farmers depends on the level of feed efficiency of the lambs raised. Promoting breed selection for feed efficiency could provide sheep farmers with higher quality and more economically profitable lambs. In livestock production, marker-assisted selection employs genetic biomarkers linked to specific traits. Myostatin (MSTN), a vital transforming growth factor-beta superfamily member, is pivotal in regulating myogenesis and negatively impacts mammal muscle growth and development. The study aims to find molecular markers related to feed efficiency parameters in the MSTN gene for Latvian sheep breeds. DNA extraction was made from blood collected from 76 controlled fatten lambs, with 63.16% belonging to the Latvian Dark-head (LT) breed. A complete gene sequencing analysis was conducted to identify variations in loci across different sheep breeds, aiming to discover statistically significant associations between identified polymorphisms and feed efficiency indicators. Polymorphic variants were identified in 23 loci of the MSTN gene among Latvian lambs, with the discovery of a novel SNP. Notably, SNP rs404916326 T>A exhibited statistically significant associations with indicators such as Residual feed intake, Residual intake, and body weight gain, specifically in the LT breed. Furthermore, SNP rs408469734 G>A showed associations with relative growth rate and Kleiber's ratio within the lamb group. These findings suggest that SNPs rs404916326 and rs408469734 within the MSTN gene are promising molecular markers for marker-assisted selection strategies in sheep breeding to improve feed efficiency indicators.