Influência das concentrações de AGNE na qualidade oocitária e produção in vitro de embriões de vacas Holandesas no início da lactação
Palavras-chave: Balanço energético negativo. OPU/PIV. Taxa de blastocisto. Perfil metabólico. ABSTRACT SALA, R. V. Influence of NEFA concentrations on oocyte quality and in vitro embryo production in Holstein cows during early lactation. [Influência das concentrações de AGNE na qualidade oocitária e produção in vitro de embriões de vacas Holandesas no início da lactação]. 2013. 87 f. Dissertação (Mestrado em Ciências) -Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo,
... de de São Paulo, São Paulo, 2013. The present study evaluated the influence of the days postpartum and the concentrations of non-esterified fatty acids (NEFA -High vs. Low) on concentrations of metabolites (β-hydroxybutyrate and glucose), oocyte quality and in vitro embryo production of Holstein cows during early lactation (90 days postpartum). The experiment was carried out in a commercial dairy farm (Santa Rita -Agrindus S/A), located at Descalvado -SP. At the calving moment, 30 Holstein cows were selected to be submitted to ovum pick-up (OPU) procedures each 14 days, in 5 different moments during the early lactation (30 ± 3, 44 ± 3, 58 ± 3, 72 ± 3 and 86 ± 3 days postpartum). Previously to the OPU session blood samples were collected for metabolite assay, body condition score (BCS) was recorded and the number of follicles able to be aspirated was also registered. The High and Low concentration of NEFA were stablished with the samples of day 44 ± 3 postpartum. The laboratory procedures for in vitro embryo production (in vitro maturation, fertilization and culture) were performed in the same laboratory (Bioembryo, Bauru -SP). Statistical analysis was performed by the GLM procedure of SAS. No effect was observed for different NEFA concentrations (High NEFA = 0.45 vs. Low NEFA = 0.52 mmol / L, P = 0.20), nor for days postpartum (30±3 = 0.54; 44±3 = 0.43; 58±3 = 0.43; 72±3 = 0.52 e 86±3 = 0.51 mmol/L; P=0.11) on β-hydroxybutyrate concentrations. Considering glucose concentrations there was no treatment effect (High NEFA = 61.1 vs. Low NEFA = 63.6 mg / dL, P = 0.26). However, the glucose concentrations were influenced by days postpartum (30±3 = 60.1; 44±3 = 63.0; 58±3 = 63.5; 72±3 = 62.1 e 86±3 = 63.0 mg/dL; P=0.03). Treatment (High vs. Low NEFA) did not impact the number of recruited follicles (P = 0.36), total oocytes recovered (P = 0.28) and viable oocytes (P = .25). As well as, time did not alter the amount of recruited follicles (P = 0.87), total oocytes recovered (P = 0.42) and viable oocytes (P = .44). The amount of grade I oocytes was not influenced by treatment (High NEFA vs. Low NEFA, P = 0.14). However, days postpartum reduced the quantity of grade I oocytes (P = 0.05). Also, no treatment effect (High and Low NEFA) was observed for number of cleaved oocytes per OPU session (P = 0.45) and cleavage rate (P = 0.95). In the same way, days postpartum had no influence in the amount of cleaved oocytes per OPU session (P = 0.31) and cleavage rate (P = 0.80). In addition, for the in vitro embryo production, the NEFA concentrations (High NEFA = 0.4 vs. Low NEFA = 1.2, P = 0.37) and days postpartum (30±3 = 0.4; 44±3 = 0.7; 58±3 = 0.8; 72±3 = 0.9 e 86±3 = 1.2; P=0.39) did not affect the number of blastocysts per OPU session. Also, the blastocyst rate was not influenced by treatment (High NEFA = 6.2% vs. Low NEFA = 11.6%, P = 0.51) and days postpartum (30±3 = 4.8%; 44±3 = 8.9%; 58±3 = 10.7%; 72±3 = 10.0% e 86±3 = 12.8%; P=0.41). It was concluded that high concentration of NEFA on day 44 postpartum in Holstein cows did not alter the concentrations of βhydroxybutyrate and glucose, as well as, the oocyte quality and in vitro embryo production. However, the increase in days postpartum elevated the glucose concentrations and decreased the number of grade I oocytes of Holstein cows submitted to OPU and in vitro embryo production up to 90 days postpartum.