Viabilidade in vitro de espermatozóides ovinos criopreservados em meios contendo lipoproteínas de baixa densidade nas formas natural ou liofilizada

• Ano de defesa: 2009
• Autor(a) principal: Valeria Spyridion Moustacas
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: sêmen ovino; LDL; Criopreservação; Reprodução animal; Espermatozóides; Lipoproteínas; Ovino Reprodução
• Link de acesso: http://hdl.handle.net/1843/SSLA-83GPVA

The aim of the present work was to evaluate the efficiency of the addition of natural and lyophilized low density lipoproteins (LDL) instead of egg yolk to ram semen extender during cryopreservation. Two ejaculates from 10 rams were collected and sperm motility, mass motility, vigor, number, reactivity to the hypoosmotic swelling test and morphology were evaluated. Ejaculates presenting sperm motility 70%, vigor 3 and sperm pathologies 30% were frozen. Ejaculates were distributed in 9 treatments: (T1) 16% egg yolk -Tris (control), (T2-T5) Tris - 8, 12, 16 and 20% of natural LDL, respectively, (T6-T9) Tris - 8, 12, 16 and 20% of lyophilized LDL, respectively. Samples were ressuspended to 100x106 sperm/ mL and packaged into 0.25mL straw, cooled to 5°C during three hours, and frozen in liquid nitrogen. Sperm total and progressive motility, and kinetic were analyzed using computadorized analyses system (CASA). Percentage of spermatozoa with functional integrity of plasma membrane was assessed by the hypoosmotic swelling test (HOST), sperm membrane physical integrity with Propidium Iodide (PI) and acrosome integrity with FITC-PSA using an epifluorescent microscope. There was no difference of sperm characteristics evaluated among different concentrations of natural LDL and egg yolk added to the extenders (P>0.05): total motility (T1: 20.9 ± 11.9 and T2-T5: 25.9 ± 13.6 %), progressive motility (T1: 6.6 ± 4.2 and T2-T5: 11.7 ± 7.5 %), HOST+ (T1: 23.7 ± 6.9 and T2-T5: 23.2 ± 8.7 %) and PI-/PSA- (T1: 13.8 ± 7.8 and T2-T5: 18.1 ± 7.8 %). Nevertheless, LDL lyophilization process was unable to preserve function of lipoproteins, since the sperm parameters evaluated showed lower values (P>0.05) compared to natural LDL and control groups