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Metabolomic profile differs between Holstein strains at grazing conditions during early and mid lactation.

E. Jorge-Smeding

Abstract:

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Metabolomic profile differs between Holstein strains at grazing conditions during early and mid lactation.
E. Jorge-Smeding*1, D. Armand-Ugon2, A. Mendoza2, M. Carriquiry1, A. Astessiano1. 1Departamento de Producci�n Animal y Pasturas, Facultad de Agronom�a, Universidad de la Rep�blica Montevideo, Uruguay, 2Programa de Producci�n de LecheUnidad de Lecher�a, Estaci�n Experimental INIA La Estanzuela, Instituto Nacional de Investigaci�n Agropecuaria Colonia, Uruguay.

The objective of this study was to evaluate the effect of Holstein strain on plasma metabolome to understand physiological adaptation at grazing of Holstein cows of 2 genetic origins: American (HFA, n = 8; 588 kg live weight, 2.60 BCS) and New Zealand (HFNZ, n = 8, 524 kg live weight, 2.50 BCS) during early and mid-lactation. Multiparous cows were used. Cows were fed 64% pastures, 31% of concentrate and 5% on average. Cows produced 33.0 vs. 30.4 � 2.0 kg/d of milk for HFA and HFNZ respectively (P = 0.02), without differences between genetic strains in body condition score (P = 0.10). Plasma were collected at 21 and 180 d in milk and analyzed using a targeted metabolomic approach through a gas chromatography/time-of-flight mass spectrometry method. A total of 172 metabolites were quantified. According to principal component analysis, data were clustered in 2 groups corresponding to DIM and a partial least square discriminant analysis classification model was obtained (R2 = 0.95; Q2 = 0.40) being oxoproline, p-tolyl glucuronide, 5-hydroxynorvaline, erythritol and isoleucine the 5 metabolites with the highest score of variable importance in the projection (VIP score >2.0 in all cases). Univariate analysis (false discovery rate-corrected ANOVA) showed 68 metabolites differing (adj-P < 0.05) between strains and 5 that tended (adj-P < 0.10) to be affected by the interaction between strain and DIM, but none of the metabolites were affected by DIM. Most of these differing metabolites belonged to amino acid metabolism (n = 26), fatty acids (n = 11), kidney deficiency pathways (n = 4), bile acids (n = 3) and the others composed single metabolite classes. There was not a clear trend on the effect of strain for most of the metabolite families as — on average— within each group (AA, fatty acid, kidney deficiency pathways, bile acids), half of the metabolites had a fold change >1.0 and half <1.0 for HFNZ compared with HFA cows. However, with the exception of linoleic and stearic acid, all fatty acids were increased in HFNZ compared with HFA cows (e.g., palmitoleic, arachidonic acids, adj-P < 0.05, fold change >1.0 in all cases). The effect of genetic strain on metabolic adaptations to pastoral constrains seems to rely, at least in part, on nitrogen metabolism.

Keywords: Holstein strains, grazing, metabolomics.

Biography: 27 years old. Agronomic engineer from Uruguay. Currently working at the Department of Animal Sciences and Pastures of the Agronomic College of Universidad de la Rep�blica. Passionate for dairy cows and milk production systems based on grazing.