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Low density lipoproteins added to an extender frozen or lyophilizedare evenly efficient in cryoprotecting ovine sperm cells than when 16% whole egg yolk was added AbstractThe aim of this study was to test different concentrations of low density lipoprotein (LDL) in replacement of whole egg yolk in extenders preserved in the aqueous or lyophilized form, for ram sperm cryopreservation using two freezing curves (-40°C/min from 5 to -140°C and nitrogen vapor). One ejaculate from six Santa Inês rams was collected. Each ejaculate was divided into nine different diluents as follows: Tris-16% yolk (control), and Tris with 2, 4, 6 and 8% fresh LDL, and criopreserved in the aqueous or lyophilized form. The samples were diluted to a final concentration of 100 x 10 6 sperm/mL and filled into 0.25 ml straws. After thaw, sperm cells were evaluated for motility and sperm kinetics (CASA), and submitted to the hypoosmotic swelling test and the evaluation of the structural integrity of sperm membranes using fluorescent dyes (CFDA: PI), as well as sperm morphology and longevity. The experimental design was randomized blocks, and results were submitted to ANOVA and the averages were compared using the Scott-Knott test. There were no differences in progressive motility and functional and structural integrity of the membrane evaluated when different concentrations of aqueous or lyophilized low density lipoproteins or egg yolk were added to the extender (P>0.05). As for the velocity of sperm movement, the control medium had some kinetic scores similar to the extender containing LDL, both aqueous and lyophilized (P> 0.05). Results were similar between cooling curves. Therefore, we conclude that the media containing all concentrations of LDL, aqueous or lyophilized, were able to protect the ram sperm cells during the cryopreservation process, as whole egg yolk did. ResumoO objetivo deste trabalho foi testar para criopreservação de sêmen ovino diferentes concentrações de lipoproteína de baixa densidade (LBD) em substituição à gema de ovo em meios diluidores, armazenados na forma aquosa e liofilizada, utilizando-se duas curvas de congelação (-40°C/min de 5 à -140°C ou vapor de nitrogênio). Os ejaculados de seis carneiros da raça Santa Inês foram fracionados e distribuídos em nove tratamentos, sendo o primeiro o meio controle (Tris-gema 16%) e os demais meios Tris contendo lipoproteínas de baixa densidade nas concentrações de 2, 4, 6 e 8% (v/v), criopreservados tanto na forma aquosa quanto liofilizada. As amostras foram diluídas para a concentração final de 100 x 10 6 espermatozoides/mL e envasadas em palhetas de 0,25 mL. Após a descongelação foram avaliadas a motilidade e cinética espermática (CASA), morfologia e longevidade espermáticas, além da integridade funcional (HOST) e estrutural (CFDA/IP) das membranas. O delineamento experimental foi blocos ao acaso e os resultados foram submetidos a ANOVA, sendo as médias comparadas pelo teste de Scott-Knott. Quanto aos parâmetros de motilidade progressiva e integridade funcional e estrutural...

The objectives of the present study were to obtain posterior densities of genetic parameters for scrotal circumference (SC), testicular volume (TV), BW, and age at puberty, to determine their correlations, and to evaluate the inclusion of these traits as selection criteria for sexual precocity in Guzerat bulls. Two-trait analyses were performed including records of SC, TV, and BW at 365, 450, 550, 650, 730, 850, and 970 d of age with age at puberty of 1,783 Guzerat bulls born between 2000 and 2011. The (co)variance components were estimated using Bayesian methods. Posterior means of heritability ranged from 0.45 to 0.60 for SC, from 0.35 to 0.55 for TV, and from 0.39 to 0.60 for BW. Posterior means of heritabilities for age at puberty using the two-trait analysis with SC ranged from 0.46 to 0.55, those with TV ranged from 0.49 to 0.57, and those with BW ranged from 0.49 to 0.62. The genetic correlation between age at puberty and SC ranged from -0.52 to -0.85, those between age at puberty and TV ranged from -0.33 to -0.66, and those between age at puberty and BW ranged from -0.38 to -0.72. In general, the same trend was observed for the phenotypic correlation between age at puberty and SC, TV, and BW. The selection of the top 10% of young males for SC, TV, or BW caused a decrease in age at puberty, with the most favorable expected correlated response in age at puberty at 650 d of age (-119.95 ± 15.1 d per generation), 730 d of age (-82.20 ± 20.9), and 850 d of age (-93.68 ± 21.5), respectively. In conclusion, SC, TV, and BW can be used as selection criteria to improve early sexual development in Guzerat bulls, and SC measured at 650 d of age is the most advantageous indicative selection criterion for improvement of age at puberty in Guzerat young bulls.

The aim of this study was to evaluate the motility, kinetics and membrane integrity of ovine sperm cryopreserved in extenders containing 8% LDL with enzymatic antioxidants at different concentrations. Four Santa Inês rams were used to form four pools of semen (each pool containing ejaculates from four ram, totaling four ejaculates per animal). Each seminal pool was divided into eight aliquots for the following treatments: 1) Tris-glucose-glycerol (TGG) + (16%) egg yolk (control 1); 2) TGG + 8% (w/v) LDL (control 2); 3) TGG + 8% LDL + catalase 100 U/mL; 4) TGG + 8% LDL + catalase 200 U/mL; 5) TGG + 8% LDL + superoxide dismutase 100 U/mL; 6) TGG + 8% LDL + superoxide dismutase 200 U/mL; 7) TGG + 8% LDL + reduced glutathione 5 mM; and 8) TGG + 8% LDL + reduced glutathione 10 mM. The samples were packed into 0.25 mL straws, cooled (-0.25 °C/ min), maintained at 5 °C for 2 h and then frozen (-25 °C/ min) using a TK4000 ® . Immediately after thawing (38 °C/ 30 s), sperm motility and movement characteristics were assessed by computer sperm analysis (CASA). The structural integrity of the plasma and acrosomal membranes was analyzed using fluorescent dyes. The functional integrity of membranes was assessed using a hypoosmotic swelling test. As assessed by ANOVA, significant differences (P<0.05) among treatments were only observed for VCL, VSL and VAP. For the VCL variable, the 2, 3, 4, 5, 6 and 7 extenders were similar and higher than 1 and 8 extenders, the latter being similar to each other. For the VSL variable, the 3, 4, 5, 6 and 7 extenders were similar and higher than 1, 2 and 8 extenders, the latter being similar to each other. For the VAP variable, the 3, 4 and 6 extenders were similar and higher than 1, 2, 5, 7 and 8 extenders, the latter being similar to each other. In conclusion, enzymatic antioxidants as catalase and superoxide dismutase improve the protective activity of extenders containing LDL on frozen ovine sperm. concentrações. Quatro carneiros da raça Santa Inês foram utilizados para formar quatro pools de sêmen (cada pool contendo ejaculados provenientes dos quatro carneiros, totalizando quatro ejaculados por animal). Cada pool de sêmen foi dividido em oito alíquotas para os seguintes tratamentos: 1) Trisglicose-glicerol (TGG) + (16%) gema de ovo (controle 1); 2) TGG + 8% (g/L) LDL (controle 2); 3) TGG + 8% LDL + catalase 100 U/mL; 4) TGG + 8% LDL + catalase 200 U/mL; 5) TGG + 8% LDL + superóxido dismutase 100 U/mL; 6) TGG + 8% LDL + superóxido dismutase 200 U/mL; 7) TGG + 8% LDL + glutationa reduzida 5 mM; and 8) TGG + 8% LDL + glutationa reduzida 10 mM. As amostras foram envasadas em palhetas de 0,25 mL, resfriadas (-0,25 °C/min), mantidas a 5 °C por duas horas e em seguida congeladas (-25 °C/ min) usando uma máquina de congelar TK4000 ® . Imediatamente depois da descongelação (38 °C/30 s), as amostras foram submetidas à análise computadorizada (CASA) para avaliação da motilidade e cinética. A integridade estrutural das membranas plasmática e acrossomal foi analisada utilizando corantes fluor...