Variants in GH, IGF1, and LEP genes associated with body traits in Santa Inês sheep

Growth hormone (GH), insulin-like growth factor 1 (IGF1), and leptin (LEP) can be candidate genes for association studies because they play vital roles in the metabolism process. Thus, this study aimed to identify variants in these genes associated with body traits in Santa Inês sheep. The following were recorded: body weight at 100 (BW100) and 240 days (BW240), average daily gain (ADG), withers (WH) and croup (CH) heights, body length (BL), thoracic (TG) and leg (LG) girths, thoracic (TW) and croup (CW) widths, body depth (BD), rib eye area (REA), fat thickness (FT), and carcass finishing score (CFS). Single-locus association analysis was performed with 11 variants in IGF1, 18 in LEP, and 16 in GH. Moreover, two haplotypes in IGF1 and one haplotype in LEP were evaluated in haplotype association analysis. The single-locus analysis revealed 23 suggestive additive effects (p < 0.05), but no additive effect was found at the Bonferroni threshold. Haplotype association analysis revealed 19 additive effects, of which ten were at the Bonferroni threshold (p < 0.0074). In IGF1 gene, haplotype replacements were associated with ADG 20.51(7.37), CH 4.09(1.21), WH 3.52(1.20), BL 3.94(1.19), TG 3.88(1.30), TW 1.13(0.36), and LG 3.40(1.08); while in the LEP gene the haplotype replacement was associated with BW100 1.83(0.51), BD −2.51(0.56), and CFS −0.24(0.06). Therefore, there are haplotypes in IGF1 and LEP genes associated with body traits in Santa Inês sheep, which can be useful in marker-assisted selection.

Variants in GH, IGF1, and LEP genes associated with body traits in Santa Inês sheep

Growth hormone (GH), insulin-like growth factor 1 (IGF1), and leptin (LEP) can be candidate genes for association studies because they play vital roles in the metabolism process. Thus, this study aimed to identify variants in these genes associated with body traits in Santa Inês sheep. The following were recorded: body weight at 100 (BW100) and 240 days (BW240), average daily gain (ADG), withers (WH) and croup (CH) heights, body length (BL), thoracic (TG) and leg (LG) girths, thoracic (TW) and croup (CW) widths, body depth (BD), rib eye area (REA), fat thickness (FT), and carcass finishing score (CFS). Single-locus association analysis was performed with 11 variants in IGF1, 18 in LEP, and 16 in GH. Moreover, two haplotypes in IGF1 and one haplotype in LEP were evaluated in haplotype association analysis. The single-locus analysis revealed 23 suggestive additive effects (p < 0.05), but no additive effect was found at the Bonferroni threshold. Haplotype association analysis revealed 19 additive effects, of which ten were at the Bonferroni threshold (p < 0.0074). In IGF1 gene, haplotype replacements were associated with ADG 20.51(7.37), CH 4.09(1.21), WH 3.52(1.20), BL 3.94(1.19), TG 3.88(1.30), TW 1.13(0.36), and LG 3.40(1.08); while in the LEP gene the haplotype replacement was associated with BW100 1.83(0.51), BD −2.51(0.56), and CFS −0.24(0.06). Therefore, there are haplotypes in IGF1 and LEP genes associated with body traits in Santa Inês sheep, which can be useful in marker-assisted selection.(AU)

The effects of gelatin supplementation prior to cooling on ram semen quality and fertility

The physical and chemical characteristics of gelatin have been used to justify its inclusion in extenders to preserve the sperm quality and improve results of cervical artificial insemination with cooled semen. The objective of this study was to evaluate the effects of gelatin supplementation in cooling extender on the quality and fertility of ram semen stored at 5°C. Semen samples (n = 24) of Santa Inês rams (n = 6) were diluted in Glycine-Yolk-Milk extender without (control) or with 1.5% of gelatin. The samples were loaded into 0.25 mL straws, cooled to 5°C and stored vertically for 48 and 72 hours. Sample quality was evaluated using straw homogeneity tests based on pH, osmolality and the proportion of spermatozoa (PS) in both upper and lower segments of straws (US and LS), analyses of sperm motility, plasma and acrosomal membrane integrity, and by fertility after artificial insemination. Differences between the US and LS of straws were found for pH and PS (%). They were significant only in the control group at both times: pH 5.96 vs. 5.71 at 48 h and 6.13 vs. 5.89 at 72 h; PS 21.66 vs. 78.34 at 48 h and 20.87 vs. 79.13 at 72 h. Storage in gelatin had very little, to no effect on the sperm kinetics or on the sperm membrane integrity evaluations. The addition of gelatin to the extender did not affect the pregnancy rate which ranged from 4.4 to 26.1%. We conclude that gelatin is effective in maintaining the physical and chemical homogeneity of the semen samples. Further research is needed in order to optimize the use of gelatin supplementation and elucidate any potential benefits.(AU)

The effects of gelatin supplementation prior to cooling on ram semen quality and fertility

The physical and chemical characteristics of gelatin have been used to justify its inclusion in extenders to preserve the sperm quality and improve results of cervical artificial insemination with cooled semen. The objective of this study was to evaluate the effects of gelatin supplementation in cooling extender on the quality and fertility of ram semen stored at 5°C. Semen samples (n = 24) of Santa Inês rams (n = 6) were diluted in Glycine-Yolk-Milk extender without (control) or with 1.5% of gelatin. The samples were loaded into 0.25 mL straws, cooled to 5°C and stored vertically for 48 and 72 hours. Sample quality was evaluated using straw homogeneity tests based on pH, osmolality and the proportion of spermatozoa (PS) in both upper and lower segments of straws (US and LS), analyses of sperm motility, plasma and acrosomal membrane integrity, and by fertility after artificial insemination. Differences between the US and LS of straws were found for pH and PS (%). They were significant only in the control group at both times: pH – 5.96 vs. 5.71 at 48 h and 6.13 vs. 5.89 at 72 h; PS – 21.66 vs. 78.34 at 48 h and 20.87 vs. 79.13 at 72 h. Storage in gelatin had very little, to no effect on the sperm kinetics or on the sperm membrane integrity evaluations. The addition of gelatin to the extender did not affect the pregnancy rate which ranged from 4.4 to 26.1%. We conclude that gelatin is effective in maintaining the physical and chemical homogeneity of the semen samples. Further research is needed in order to optimize the use of gelatin supplementation and elucidate any potential benefits.

Biotecnologias de seleção, conservação e multiplicação de recursos genéticos de ovinos Santa Inês

The preservation of animal genetic biodiversity is fundamental to food security. Santa Ines (SI) is an important native Brazilian hair sheep breed that should be preserved by biotechnologies of selection, conservation and multiplication. The molecular biotechnology identify genes of interest that have an impact on the reproductive, productive and health performance, adding value to these animals, while reproduction biotechnologies, especially semen cryopreservation and artificial insemination, are used for multiplication, conservation and dissemination of this germplasm. Activities related to the conservation and adding value to SI should continue to be stimulated otherwise an irretrievable loss of its originality and genetic diversity can happen.

A preservação da biodiversidade genética dos animais é fundamental para a segurança alimentar. O ovino Santa Inês (SI) é um importante patrimônio genético autóctone brasileiro que deve ser conservado através do uso de biotecnologias para seleção, conservação e multiplicação. As biotecnologias moleculares identificam genes de interesse que têm impacto sobre o desempenho reprodutivo, produtivo e sanitário, agregando valores a estes animais, enquanto que, as biotecnologias da reprodução, em especial a criopreservação do sêmen e inseminação artificial, são utilizadas para a multiplicação, conservação e disseminação deste germoplasma. As atividades relacionadas à conservação e agregação de valores ao ovino SI devem continuar sendo estimuladas sob pena de uma irrecuperável perda da sua originalidade e diversidade genética.

Biotecnologias de seleção, conservação e multiplicação de recursos genéticos de ovinos Santa Inês

The preservation of animal genetic biodiversity is fundamental to food security. Santa Ines (SI) is an important native Brazilian hair sheep breed that should be preserved by biotechnologies of selection, conservation and multiplication. The molecular biotechnology identify genes of interest that have an impact on the reproductive, productive and health performance, adding value to these animals, while reproduction biotechnologies, especially semen cryopreservation and artificial insemination, are used for multiplication, conservation and dissemination of this germplasm. Activities related to the conservation and adding value to SI should continue to be stimulated otherwise an irretrievable loss of its originality and genetic diversity can happen.(AU)

A preservação da biodiversidade genética dos animais é fundamental para a segurança alimentar. O ovino Santa Inês (SI) é um importante patrimônio genético autóctone brasileiro que deve ser conservado através do uso de biotecnologias para seleção, conservação e multiplicação. As biotecnologias moleculares identificam genes de interesse que têm impacto sobre o desempenho reprodutivo, produtivo e sanitário, agregando valores a estes animais, enquanto que, as biotecnologias da reprodução, em especial a criopreservação do sêmen e inseminação artificial, são utilizadas para a multiplicação, conservação e disseminação deste germoplasma. As atividades relacionadas à conservação e agregação de valores ao ovino SI devem continuar sendo estimuladas sob pena de uma irrecuperável perda da sua originalidade e diversidade genética.(AU)

Manejo reprodutivo: foco na taxa de reprodução / Reproductive management: focus on reproduction rate

A exploração racional dos ovinos de corte deve voltar-se para a produtividade dos animais e a rentabilidade econômica do sistema de produção. Contudo, não esquecendo o respeito ao equilíbrio agroecológico, ao impacto social quanto a geração e qualidade do emprego e ao não uso de mão de obra infantil. Também, a ética e a rastreabilidade ao longo de todo o processo produtivo. É muito importante o uso de inovações tecnológicas apropriadas aos diferentes sistemas de produção; o investimento na organização e na inovação na gestão da unidade produtiva em sintonia com a cadeia produtiva; a assistência técnica e a qualificação de mão de obra. Quando as condições físicas da unidade produtiva, o regime de manejo, o bem-estar animal, os manejos alimentar e da nutrição, o manejo da promoção da saúde, o genótipo e o mercado são favoráveis deve-se buscar a otimização do retorno econômico da atividade. Para tanto, o uso de técnicas reprodutivas como estação de monta, sincronização do estro e da ovulação, inseminação artificial, transferência de embriões, diagnóstico precoce de gestação e indução do parto é fundamental. A idade e o peso a primeira cobertura e ao primeiro parto, a fertilidade ao parto, a prolificidade, a sobrevivência e desenvolvimento das crias, o período de serviço, o período entre o parto e a concepção e o intervalo de partos são parâmetros muitos importantes para a eficiência reprodutiva. Com este foco, ressalta-se o impacto positivo que a taxa de reprodução exerce sobre o desfrute dos rebanhos e a rentabilidade da unidade produtiva.

Rational exploitation of meet sheep should focus on animal productivity and economic profitability of the production system. However, it is important not to forget the respect for the environment, respect for the social impact as the generation and quality of employment and failure to use child labor, ethics and traceability throughout the entire production process. On the other hand, it is very important to use appropriate technologic innovations on different production systems; investment in organization and innovation on the management of the productive unit, technical assistance and technical qualification of labor. When the productive units physical condition, management regime,animal well-being, food and nutrition management systems, management of health promotion, genotype and market allows it should seek to optimize economic return from the activity. Thus, the use of reproductive biotechnologies as breeding season, estrus synchronization and ovulation, artificial insemination, embryo transfer, early pregnancy diagnosis and induction of labor is crucial. The age and body weight at first mating and parturition, fertility at parturition, prolificacy, survival and development of the offspring, service period, period between birth and conception and calving interval are very important parameters to express the reproductive efficiency. With all this in mind, the positive impact that reproduction rate has on the profitability of the productive unit is herein highlighted.

Estimação de parâmetros genéticos de ovinos da raça Santa Inês utilizando modelos uni e bicaracterística / Estimation of genetic parameters Santa Inês Sheep breed using single and two - traits models

Objetivou-se nesse trabalho, estimar os parâmetros genéticos para características de crescimento em ovinos da raça Santa Inês através do Método da Máxima Verossimilhança Restrita (REML). Os componentes de (co)variâncias e os parâmetros genéticos foram estimados pelo Software MTDFREML (Multiple Trait Derivative-Free Restricted Maximum Likelihood). As características avaliadas em modelos uni e bicaracterística foram: peso ao nascimento (PN) e peso ao desmame (P90). Além dos efeitos fixos de sexo, grupo contemporâneo e tipo de parto, foram utilizados os seguintes efeitos aleatórios: efeito genético aditivo direto, efeito genético aditivo materno e efeito residual. As estimativas de herdabilidade aditiva direta para PN foram 0,20 e 0,21, para os modelos uni e bicaracterística, respectivamente. As estimativas de herdabilidade aditiva direta para P90 foram 0,04 e 0,07, para os modelos uni e bicaracterística, respectivamente. A correlação genética entre PN e P90 foi de 0,11, indicando que ambas as características devem ser trabalhadas simultaneamente.(AU)

The objective of this study is to estimate genetic parameters for growth traits in sheep Santa Ines breed by Restricted Maximum Likelihood (REML). The (co)variance components and genetic parameters were estimated by MTDFREML Software (Multiple Trait Derivative-Free Restricted Maximum Likelihood). The characteristics evaluated in single and two-trait models were: birth weight (BW) and weaning weight (WW). In addition to the fixed effects of sex, contemporary group and parity type, we used the following random effects: direct genetic effect, maternal additive genetic and residual effects. The direct additive heritability estimates for BW were 0.20 and 0.21 for single and two-trait models, respectively. Heritability estimates for direct additive WW were 0.04 and 0.07 for single and two-trait models, respectively. The genetic correlation between BW and WW was 0.11, indicating that both traits should be worked on simultaneously.(AU)

Avanços na criopreservação do sêmen ovino I: diluidores e crioprotetores / Advances in cryopreservation of ram semen I: extenders and cryoprotectans

A eficácia da utilização de sêmen ovino congelado em programas de inseminação artificial necessita do desenvolvimento de diluidores e protocolos de congelação que melhorem a taxa de gestação das fêmeas inseminadas. Este trabalho tem como objetivo fazer um levantamento dos principais diluidores, aditivos, crioprotetores penetrantes e não penetrantes que veem sendo empregados, visando incrementar os níveis de manutenção dos parâmetros espermáticos, após o processo de congelação-descongelação. Pode-se considerar que índices superiores de viabilidade do sêmen ovino pós-descongelação podem ser obtidos com alterações na composição do meio de congelação, seja com ajustes dos seus componentes, seja com a introdução de aditivos que inibam a ocorrência de alterações espermáticas durante o processo de criopreservação. Para tanto, as possíveis modificações propostas devem contemplar as características intrínsecas do sêmen da espécie e a variabilidade individual entre animais. É importante ressaltar que um adequado processo de criopreservação do sêmen necessita que todas as etapas sejam conduzidas de forma integrada, para que, dessa forma, sejam maximizados os índices de fertilidade do sêmen ovino congelado.

The effectiveness of using frozen sheep semen in artificial insemination programs requires the development of extenders and freezing protocols that will increase pregnancy rate of inseminated females. This work aimed to survey the main extenders, additives and external and internal cryoprotectants that have been employed to improve the maintenance levels of sperm parameters after the freezing-thawing process. Better rates of post-thawing sheep sperm viability may be obtained with changes in the freezing extender composition, whether by the adjustment of its components or by introducing additives that inhibit the occurrence of sperm changes during the cryopreservation process. Thus, the possible changes proposed must take into consideration the intrinsic characteristics of ram semen and the individual variability among animals. It is important to emphasize that the sperm cryopreservation effectiveness requires that all process steps are conducted in an integrated manner, to maximize the fertility rate of frozen ram semen.

Avanços na criopreservação do sêmen ovino I: diluidores e crioprotetores / Advances in cryopreservation of ram semen I: extenders and cryoprotectans

A eficácia da utilização de sêmen ovino congelado em programas de inseminação artificial necessita do desenvolvimento de diluidores e protocolos de congelação que melhorem a taxa de gestação das fêmeas inseminadas. Este trabalho tem como objetivo fazer um levantamento dos principais diluidores, aditivos, crioprotetores penetrantes e não penetrantes que veem sendo empregados, visando incrementar os níveis de manutenção dos parâmetros espermáticos, após o processo de congelação-descongelação. Pode-se considerar que índices superiores de viabilidade do sêmen ovino pós-descongelação podem ser obtidos com alterações na composição do meio de congelação, seja com ajustes dos seus componentes, seja com a introdução de aditivos que inibam a ocorrência de alterações espermáticas durante o processo de criopreservação. Para tanto, as possíveis modificações propostas devem contemplar as características intrínsecas do sêmen da espécie e a variabilidade individual entre animais. É importante ressaltar que um adequado processo de criopreservação do sêmen necessita que todas as etapas sejam conduzidas de forma integrada, para que, dessa forma, sejam maximizados os índices de fertilidade do sêmen ovino congelado.(AU)

The effectiveness of using frozen sheep semen in artificial insemination programs requires the development of extenders and freezing protocols that will increase pregnancy rate of inseminated females. This work aimed to survey the main extenders, additives and external and internal cryoprotectants that have been employed to improve the maintenance levels of sperm parameters after the freezing-thawing process. Better rates of post-thawing sheep sperm viability may be obtained with changes in the freezing extender composition, whether by the adjustment of its components or by introducing additives that inhibit the occurrence of sperm changes during the cryopreservation process. Thus, the possible changes proposed must take into consideration the intrinsic characteristics of ram semen and the individual variability among animals. It is important to emphasize that the sperm cryopreservation effectiveness requires that all process steps are conducted in an integrated manner, to maximize the fertility rate of frozen ram semen.(AU)

Brucella ovis REO 198 natural and experimental infection in Santa Inês rams from Brazil / Infecção natural e experimental de Brucella ovis REO 198 em carneiros Santa Inês do Brazil

B. ovis pathogenicity was evaluated in experimentally inoculated and naturally infected rams. Ten animals were submitted to simultaneous conjunctival and intrapreputial inoculation with 2x109 CFU/ mL of B. ovis REO 198. After that, animals underwent physical examination and blood samples were collected for serology every week. Positive serology results started to be observed in the 3rd week, with fluctuations in titers. Clinical changes began in the 5th week after inoculation and were associated with positive serology in the acute phase of the disease. Presence of B. ovis in semen and urine culture was intermittent. Three non-inoculated animals showed natural infection. B. ovis was shed twice in semen of one serology-negative animal. The study underscored the pathogenic characteristics of B. ovis REO 198 in Santa Inês rams, as well as the importance of animals as potential sources of infection.(AU)

Patogenicidade da B. ovis foi avaliada em carneiros inoculados experimentalmente e naturalmente infectados. Dez animais foram submetidos à inoculação conjuntival e intrapreputial simultânea com 2x109 UFC/mL de B. ovis REO 198. Depois disso, os animais foram submetidos ao exame físico e amostras de sangue foram coletadas para sorologia a cada semana. Sorologia positiva começou a ser observada na terceira semana, com flutuações nas titulações. As alterações clínicas começaram na quinta semana após a inoculação e foram associadas com sorologia positiva na fase aguda da doença. A presença de B. ovis em sêmen e cultura de urina foi intermitente. Três animais não inoculados apresentaram infecção natural. B. ovis foi eliminada duas vezes em sêmen de animal com sorologia negativa. O estudo destacou as características patogênicas de B. ovis REO 198 em carneiros Santa Inês, bem como a importância dos animais como potenciais fontes de infecção.(AU)

The innovation network in animal reproduction: EMBRAPA's experience in organizing a research project on reproductive biotechnology

Background: In 2007 a broad Network project was proposed, aiming to organize in a more efficient way the different research and development actions related to new reproductive technologies in Embrapa. The initial proposal focused to develop new technological solutions to increase Brazilian livestock competitiveness; generate basic knowledge to support development of new technologies; to promote genetic improvement and evaluate dairy and beef animal models for the different ecosystems, to improve laboratorial infrastructure and promote capacity building; and to promote equal development of the technologies for the different livestock species. The final proposal, titled "Innovation Network in Animal Reproduction" was approved for the period 2008-2012. Review: The Network Project includes research activities in animal reproduction and in the interfaces of reproduction and animal health, nutrition, and genetics. A consortium of 12 of the Embrapa units, 14 Universities, 2 International Research Centers and 5 private companies are engaged in the project. The main structure follows the general guidelines of the Embrapa´s standard of network projects, being organized in 10 thematic Component Projects (CPs): CP1- Activities related to the organization of the Network, as the coordination of the CPs, financial management, promotion of meetings and workshops, and compilation of results and evaluations; CP2 ­ Development and evaluation of new technologies for the sanitary control of semen, oocytes, and embryos; CP3- Evaluation of nutritional strategies to improve reproductive efficiency; CP4- Development of methods to improve the quality and quantity of gametes used in assisted reproductive technologies; CP5- Development of in vivo and in vitro embryo production systems; CP6- Establishment of protocols for the isolation, culture and maintenance of cell lines aiming the production of animal clones; CP7- Establishment of alternative protocols to the production of transgenic or intragenic animals; CP8- Identification, selection, use and conservation of genetic resources; CP9- Validation and monitoring of technologies; CP10- Technological innovation. Conclusions: The establishment of the network allowed the organization of Embrapa's different ongoing research actions in animal reproduction in a large and multidisciplinary project. As consequences, there was a larger interaction among the different research groups of the company and external partners. The proposal of collaborative research improved the scientific production of the group and also the development of products, processes, and technical information to the private sector. The technology transference and capacity building activities were strategically reorganized in line with the scope of the Network Project. A last consequence of the network was the possibility of applying for consortium research funding opportunities. The group also expects to improve scientific collaboration and to increase the relevance of R&D projects in animal reproduction, to improve the interplay with the government agencies in charge of the establishment of laws and rules for reproductive biotechnology used in livestock, and to improve their capacity of identifying and measuring the impact of the new technologies in the different livestock production systems.

Brucella ovis REO 198 natural and experimental infection in Santa Inês rams from Brazil / Infecção natural e experimental de Brucella ovis REO 198 em carneiros Santa Inês do Brazil

B. ovis pathogenicity was evaluated in experimentally inoculated and naturally infected rams. Ten animals were submitted to simultaneous conjunctival and intrapreputial inoculation with 2x109 CFU/ mL of B. ovis REO 198. After that, animals underwent physical examination and blood samples were collected for serology every week. Positive serology results started to be observed in the 3rd week, with fluctuations in titers. Clinical changes began in the 5th week after inoculation and were associated with positive serology in the acute phase of the disease. Presence of B. ovis in semen and urine culture was intermittent. Three non-inoculated animals showed natural infection. B. ovis was shed twice in semen of one serology-negative animal. The study underscored the pathogenic characteristics of B. ovis REO 198 in Santa Inês rams, as well as the importance of animals as potential sources of infection.

Patogenicidade da B. ovis foi avaliada em carneiros inoculados experimentalmente e naturalmente infectados. Dez animais foram submetidos à inoculação conjuntival e intrapreputial simultânea com 2x109 UFC/mL de B. ovis REO 198. Depois disso, os animais foram submetidos ao exame físico e amostras de sangue foram coletadas para sorologia a cada semana. Sorologia positiva começou a ser observada na terceira semana, com flutuações nas titulações. As alterações clínicas começaram na quinta semana após a inoculação e foram associadas com sorologia positiva na fase aguda da doença. A presença de B. ovis em sêmen e cultura de urina foi intermitente. Três animais não inoculados apresentaram infecção natural. B. ovis foi eliminada duas vezes em sêmen de animal com sorologia negativa. O estudo destacou as características patogênicas de B. ovis REO 198 em carneiros Santa Inês, bem como a importância dos animais como potenciais fontes de infecção.

Integridade e funcionalidade dos espermatozóides ovinos submetidos à criopreservação após a incorporação de colesterol, desmosterol, ácido oléico-linoléico e alfa-lactoalbumina

Objetivando testar a ação do colesterol, desmosterol, ácido oléico-linoléico ou Q-Iactoalbumina sobre os espermatozóides ovinos, alíquotas de sêmen de 25 carneiros foram submetidas à criopreservação após tratamento com essas substâncias. O sêmen foi avaliado antes do processamento e após a refrigeração, descongelação e incubação quanto à, cinética pela análise subjetiva e computadorizada (CASA), morfologia, avaliação simultânea da integridade da membrana plasmática (IMP) e do acrossomo (IAC) e do potencial de membrana mitocondrial (PMM) pela associação da aglutinina de Pisum sativum conjugada ao isotiocianato de fluoresceína (FITC-PSA), iodeto de propídio (PI) e JC-1 e, status de capacitação pela c10rtetraciclina (CTC). A influência dos aditivos em poucos parâmetros não foi suficiente para sugerir a superioridade de qualquer um dos tratamentos. A criopreservação provocou prejuízos à cinética, IMP, IAC, PMM, além de induzir a capacitação e reação do acrossomo. Foram observadas diferenças entre grupos de carneiros quanto ao status de capacitação no sêmen in natura, assim como na sensibilidade desse sêmen à crioinjúria e criocapacitação. Após a descongelação, as mudanças semelhantes à capacitação foram maiores nos animais de menor IMP. A segregação dos carneiros de acordo com a crioresistência da membrana plasmática norteou o comportamento de vários outros parâmetros. Conclui-se, que o colesterol, desmosterol, ácido oléico-linoléico e alactoalbumina não protegem o sêmen ovino contra as crioinjúrias, que a congelação-descongelação é mais danosa que a refrigeração e, que existem diferenças entre grupos de indivíduos relacionadas à crioresistência e criocapacitação espermática

In order to evaluate the proteeting aetion of some substanceson ram spermatozoa, semen samples of 25 rams were colleeted and submitted to cryopreservation after treatment with cholesterol, desmosterol, oleic-linoleic acid or Q-Iactalbumin. Before the processing and after the procedures of cooling, freezing-thawing and incubation, semen was evaluated as to kínetcs by subjective and computerized analyses (CASA), morphology, simultaneously to plasma membrane integrity (PMI), acrosome integrity (ACI) and mitochondrial membrane potential (MMP) by isothiocyanate-conjugated Pisum sativum (FITCPSA), propidium iodide (PI) and JC-1 combination and as to sperm capacitation and acrosome reaction determined by chlortetracycline (CTC) assay. The influence resulted from the additives in a few parameters was not enough to suggest the superiority of any treatments. The cryopreservation process, especially the freezing-thawing, promotes damages to kinetics, PMI, ACI, MMP and induees accelerated eapacitation and acrosome reaction in spermatozoa. Differenees among groups of rams were observed regarding capacitation status in fresh semen as well as the sensibility of their semen to cryoinjury and cryocapacitation. Higher and more accelerated capacitation-like ehanges were observed in groups of rams presenting lower plasmatic membrane cryoresistance after thawing. The segregation of rams in different levels of PMI influenced the behavior of several other parameters. It was concluded that cholesterol, desmosterol, oleic-Iinoleic acid and Q-Iactalbumin do not protect the ram semen against the cryoinjuries as well as freezing-thawing is more harmful than cooling. Important differenees among groups of individuais were noticed as for the spermatozoa resistance to the damages provoked by cryopreservation such as the eryocapacitation susceptibility