Associação de SNPs nos genes para κ-caseína e β-lactoglobulina com curvas de lactação em cabras leiteiras

Abstract

Resumo -O objetivo deste trabalho foi identificar o modelo com melhor ajuste aos dados de produção de leite, gordura, proteína e sólidos totais para cabras leiteiras, bem como associar polimorfismos de nucleotídeo único (SNPs) nos genes para κ-caseína (κ-CSN3) e β-lactoglobulina (β-LG) aos parâmetros das curvas de produção e qualidade do leite. Foram avaliados 4.160 registros de produção de leite, gordura, proteína e sólidos totais de cabras das raças Alpina, Saanen e mestiça, no Estado de Antioquia, na Colômbia. Os modelos não lineares com melhor ajuste à estrutura dos dados foram os de Nelder, para produção de leite, e de Cappio-Borlino, para qualidade do leite. As análises de associação mostraram efeito significativo do SNP κ-CSN3 sobre o pico de produção, a produção inicial e a persistência das características qualitativas do leite. Já o SNP β-LG apresentou efeito significativo sobre os picos de produção de leite e gordura, e sobre o tempo necessário para atingir o pico de produção de proteína. A identificação e a estimação da influência dos marcadores SNP avaliados sobre as curvas de lactação e a qualidade do leite podem contribuir para a seleção de caprinos leiteiros.Termos para indexação: Capra hircus, controle leiteiro, modelos não lineares, polimorfismo de nucleotídeo único, qualidade do leite, seleção assistida por marcadores. Association of SNPs in the genes for κ-casein and β-lactoglobulin with lactation curves in dairy goatsAbstract -The objective of this work was to identify the model that best fits production data of milk, fat, protein, and total solids for dairy goats, as well as to associate single-nucleotide polymorphisms (SNPs) in the genes for κ-casein (κ-CSN3) and β-lactoglobulin (β-LG) with parameters from lactation and milk-quality curves. A total of 4,160 production records of milk, fat, protein, and total solids from goats of the Alpine, Saanen, and crossbred breeds, in the state of Antioquia, Colombia, were evaluated. The nonlinear models with the best fit to data structure were Nelder's, for milk yield, and Cappio-Borlino's, for milk quality. Association analyzes showed significant effect of the SNP κ-CSN3 on production peak, initial production, and persistence of milk-quality traits. The SNP β-LG had significant effect on the peaks of milk and fat yield, and on the time required to reach the peak of protein yield. The identification and estimation of the influence of the evaluated SNP markers on lactation and milk-quality curves can contribute for dairy goat selection.

Genetic Evaluations of Dairy Goats With Few Pedigree Data: Different Approaches to Use Molecular Information

“…The descriptive statistics for the lactation curves traits (cumulative production at 210 days Lactation (P210), peak production (PP), and persistence (PER)) in goats of the Colombian tropics in the Department of Antioquia are presented in Table 1. The averages for the traits P210, PP, and PER were 318 Kg, 2.56 Kg, and 70.46%, respectively; these values are within the range reported for dairy goats (Cañas Álvarez et al, 2009;Cardona et al, 2015). Model comparison, variance components, and heritabilities: During the chain analysis, all the values of the additive genetic variance, residual, and heritability converged (Z-score value and the Geweke p-value) for all the tested models: i) MAPED (considered only pedigree data), ii) MAgPEDCLUS (considered pedigree and molecular genetic groups as xed effects), iii) MMMOL (considered genomic relationships), and iv) MAgMOLCLUS (considered genomic relationships and molecular genetic groups as xed effects).…”

Linear and nonlinear models to describe the lactation curve of Girolando cows

“…The average yield was calculated every 20 days until 310 days of lactation. Seventeen lactation-curve modelsnamed after the authors of each study -were used to analyze the behavior of the lactation curves (Table 1), as adapted from Calvo Cardona et al (2015).…”

Effect of IGF-1 and LEP/ob SNPs on growth parameters of Blanco Orejinegro cattle

“…Where, is the parameter evaluated for growth in animal i; μ is the general mean of the evaluated traits, and are the fixed effects of herd, season of birth, year of birth and sex of the individuals, respectively. is the effect of the marker variant of the individually evaluated SNPs and is the random error associated with each observation (Cardona et al, 2015). The lm function was used and the means of the genotypes were compared using the lsmeans package (Lenth, 2016), through the Tukey test in the R software (R Core Team, 2020).…”