Efecto de la línea genética Holstein sobre la capacidad de adaptación metabólica de vacas multíparas en pastoreo

El objetivo de este trabajo fue estudiar el efecto de la línea genética Hosltein (origen americano, NAH, vs. neozelandés, NZH) sobre las adaptaciones metabólicas de vacas en pastoreo. El trabajo 1 evaluó el efecto de la línea genética (NAH, n = 20; NZH, n = 20) y dos estrategias de alimentación basadas en un consumo de pasturas en torno al 40 % de la dieta anual (P30) o pastoreo maximizado (PMAX), sobre el metabolismo energético, proteico y redox. Los animals NZH tuvieron una menor (P = 0,02) producción de leche corregida por grasa y proteína que estuvo asociada a una mayor (P = 0,01) concentración plasmática de glucosa, una tendencia a mayor insulina (P < 0,07) y menores valores del índice de desbalance fisiológico, especialmente en PMAX. Los animales NZH tuvieron una mayor (P < 0,05) concentración plasmática de urea y menor concentración de 3-metilhistidina lo que sugiere una menor movilización de músculo esquelético. También parecen haber tenido un mayor daño oxidativo (concentraciones más altas de TBARS previo al parto y una tendencia a mayores niveles de carbonilos proteicos durante la lactancia, P < 0,10) y mayor respuesta antioxidante [actividad de superóxido dismutasa, SOD, que tendió (P = 0,06) a ser alta durante más tiempo, mayor aumento (P < 0,05) de la concentración plasmática de α-tocoferol durante la lactancia]. Finalmente, el análisis de componente principal sugiere que los animales NZH tuvieron un menor desplazamiento metabólico entre las distintas etapas de la lactancia. El trabajo 2 tuvo como objetivo determinar el efecto de la línea genética (NAH, n = 8; NZH, n = 8) sobre el perfil metabolómico en plasma a lo largo la lactancia (21 vs. 180 días en leche) en el sistema PMAX. Los resultados indican que el metabolismo de los aminoácidos (AA) estuvo afectado (FDR < 0,05) tanto por la etapa de lactancia (19/46 vías afectadas) como por la línea genética durante la lactancia temprana. Esto último dado por menores concentraciones plasmáticas de valina, leucina e isoleucina en los animales NZH vs. NAH (raw-P < 0,05)

Increased dietary methionine, lysine and histidine supply modulated the heat stress-induced metabolic remodeling of dairy cows

Increasing dietary Met, Lys, and His supply without increasing the dietary protein content was reported to partially alleviate the productive and physiological impact of heat stress. Nevertheless, the metabolic pathways involved are yet to be identified. Thus, we aimed to explore the metabolic pathways associated with these positive effects and develop new metabolomics-based hypotheses. Twelve lactating Holstein cows (primiparous, n = 6; multiparous, n = 6; 42.2 ± 10.6 kg/d milk yield; 83 ± 28 days in milk) were enrolled in two 3×3 replicated Latin squares consisting of 14-day treatment periods: heat stress [HS; max. Temperature Humidity Index (THI) 84, 16.8% crude protein (CP), 1,741 g/d metabolizable protein (MP), 108 Lys, 33 Met, and 37 His (g/d)], pair feeding in thermo-neutrality (TN; max. THI 64, same diet as HS), and HS with increased Lys, Met and His supply [HS+AA; max. THI 84; 17.0% CP, 1,730 g/d MP, 179 Lys, 58 Met, and 45 His (g/d)]. Blood plasma and milk were sampled on day 14 for metabolomics profiling. Several amino acids (AA) and derivatives differed between the treatments. Plasma and milk Met, Val, Trp and α-amino adipic acid concentrations were highest in HS+AA (false discovery rate-P (FDR) &lt; 0.05). Moreover, only plasma Lys and milk His were highest in HS+AA (FDR &lt; 0.05). Some phosphatidylcholines (PC) and diglycerides had lower concentrations in HS than TN (FDR &lt; 0.05), while HS+AA had similar concentrations as TN. The pathway enrichment analysis revealed that the AA-related pathways were more significantly affected in multiparous than in primiparous cows. Our results suggest that increased supply of Met stimulated PC synthesis in HS+AA to similar concentrations as in TN. Increased Lys supply likely elevated the oxidation rate of Lys and downregulated the catabolism of other essential AA (EAA) such as Val and Trp, stimulating milk protein synthesis. No clear associations were found related to His availability. In conclusion, partial amelioration of productive and physiological effects of heat stress associated with increased dietary Met and Lys supply were likely explained by stimulated PC synthesis and increased plasma and milk concentrations of other EEA

Plasma concentrations of branched-chain amino acids differ with Holstein genetic strain in pasture-based dairy systems

International audienceAbstract In pasture-based systems, there are nutritional and climatic challenges exacerbated across lactation; thus, dairy cows require an enhanced adaptive capacity compared with cows in confined systems. We aimed to evaluate the effect of lactation stage (21 vs. 180 days in milk, DIM ) and Holstein genetic strain (North American Holstein, NAH , n = 8; New Zealand Holstein, NZH , n = 8) on metabolic adaptations of grazing dairy cows through plasma metabolomic profiling and its association with classical metabolites. Although 67 metabolites were affected ( FDR < 0.05) by DIM, no metabolite was observed to differ between genetic strains while only alanine was affected ( FDR = 0.02) by the interaction between genetic strain and DIM. However, complementary tools for time-series analysis (ASCA analysis, MEBA ranking) indicated that alanine and the branched-chain amino acids ( BCAA ) differed between genetic strains in a lactation-stage dependent manner. Indeed, NZH cows had lower ( P -Tukey < 0.05) plasma concentrations of leucine, isoleucine and valine than NAH cows at 21 DIM, probably signaling for greater insulin sensitivity. Metabolic pathway analysis also revealed that, independently of genetic strains, AA metabolism might be structurally involved in homeorhetic changes as 40% (19/46) of metabolic pathways differentially expressed ( FDR < 0.05) between 21 and 180 DIM belonged to AA metabolism

Metabolomics reveals changes in urea cycle associated to residual feed intake in growing heifers

Metabolomics reveals changes in urea cycle associated to residual feed intake in growing heifers. 6. International Symposium on Energy and Protein Metabolism and Nutrition (ISEP

Untargeted metabolomics confirms the association between plasma branched chain amino acids and residual feed intake in beef heifers

International audienceThis study explored plasma biomarkers and metabolic pathways underlying feed efficiency measured as residual feed intake ( RFI ) in Charolais heifers. A total of 48 RFI extreme individuals (High-RFI, n = 24; Low-RFI, n = 24) were selected from a population of 142 heifers for classical plasma metabolite and hormone quantification and plasma metabolomic profiling through untargeted LC-MS. Most efficient heifers (Low-RFI) had greater (P = 0.03) plasma concentrations of IGF-1 and tended to have (P = 0.06) a lower back fat depth compared to least efficient heifers. However, no changes were noted (P ≥ 0.10) for plasma concentrations of glucose, insulin, non-esterified fatty acids, β-hydroxybutyrate and urea. The plasma metabolomic dataset comprised 3,457 ions with none significantly differing between RFI classes after false discovery rate correction (FDR > 0.10). Among the 101 ions having a raw P < 0.05 for the RFI effect, 13 were putatively annotated by using internal databases and 6 compounds were further confirmed with standards. Metabolic pathway analysis from these 6 confirmed compounds revealed that the branched chain amino acid metabolism was significantly (FDR < 0.05) impacted by the RFI classes. Our results confirmed for the first time in beef heifers previous findings obtained in male beef cattle and pointing to changes in branched-chain amino acids metabolism along with that of body composition as biological mechanisms related to RFI. Further studies are warranted to ascertain whether there is a cause-and-effect relationship between these mechanisms and RFI

Metabolites identified through ion annotation and further confirmed by standards which were affected (raw-P < 0.05) by residual feed intake class (Low vs High) in beef heifers.

High and Low-RFI classes are depicted by black and empty bars, respectively. For leucine and ornithine, only the ion with the highest peak intensity was plotted.</p

Metabolites identified through ion annotation and further confirmed by standards which were affected (raw-P < 0.05) by residual feed intake class (Low vs High) in beef heifers.

Metabolites identified through ion annotation and further confirmed by standards which were affected (raw-P < 0.05) by residual feed intake class (Low vs High) in beef heifers.</p

S1 Fig -

Partial least square discriminant analysis (PLS-DA) for residual feed intake (RFI) on the basis of: a) total metabolomic dataset (3,457 ions) or b) only confirmed metabolites (annotation class 1). Score plot, and cross validation values are presented in the top and bottom of each figure panel, respectively. Red and green dots depict Low- and High-RFI, respectively. (JPG)</p

Animal performance and classical plasma blood metabolites across Low vs. High residual feed intake (RFI) heifers.

Data is presented as least square means and standard error of the mean (SEM).</p

Principal component analysis plot score according to residual feed intake class (Low vs. High RFI) of Charolais heifers.

Principal component analysis plot score according to residual feed intake class (Low vs. High RFI) of Charolais heifers.</p