RESUMEN

Artificial insemination with cooled semen is the most common practice in rabbit farms and any improvement on it helps to increase the efficiency and productivity of rabbit meat farms. Therefore, the aim of this study was to assess whether different cryoprotectant agents (CPA) as glycerol, N, N-Dimethylformamide (DMF) and N-Methyl-2-Pyrrolidone (NMP) can improve cooled rabbit sperm quality stored at 4ºC and 16ºC. Sperm samples were diluted with INRA 96® (Extender A), INRA 96® with 6% glycerol (Extender B) or 6% DMF (Extender C) or 6% NMP (Extender D) respectively and stored at 4ºC and 16ºC. Samples were then analysed at 4, 24, 48 and 72 hours after refrigeration by integrated sperm analysis system (ISAS®), eosin-nigrosin stain (vitality), hypo-osmotic swelling test (HOS test) and acrosome integrity test. Extender C showed higher percentage of motility, vitality and HOS test than extender B and D (p<0.05). Whereas sperm quality decreased over time (p<0.05), data showed that the addition of DMF kept the motility and sperm plasma membrane integrity after 24 hours of storage better than other diluents. These results suggest that the addition of DMF to INRA 96® exerts a protective effect on the membrane of spermatozoa improving seminal quality.

Asunto(s)

RESUMEN

Artificial insemination with cooled semen is the most common practice in rabbit farms and any improvement on it helps to increase the efficiency and productivity of rabbit meat farms. Therefore, the aim of this study was to assess whether different cryoprotectant agents (CPA) as glycerol, N, N-Dimethylformamide (DMF) and N-Methyl-2-Pyrrolidone (NMP) can improve cooled rabbit sperm quality stored at 4ºC and 16ºC. Sperm samples were diluted with INRA 96® (Extender A), INRA 96® with 6% glycerol (Extender B) or 6% DMF (Extender C) or 6% NMP (Extender D) respectively and stored at 4ºC and 16ºC. Samples were then analysed at 4, 24, 48 and 72 hours after refrigeration by integrated sperm analysis system (ISAS®), eosin-nigrosin stain (vitality), hypo-osmotic swelling test (HOS test) and acrosome integrity test. Extender C showed higher percentage of motility, vitality and HOS test than extender B and D (p<0.05). Whereas sperm quality decreased over time (p<0.05), data showed that the addition of DMF kept the motility and sperm plasma membrane integrity after 24 hours of storage better than other diluents. These results suggest that the addition of DMF to INRA 96® exerts a protective effect on the membrane of spermatozoa improving seminal quality.(AU)

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RESUMEN

O índice de prenhez utilizando sêmen criopreservado de garanhões é variável e, além disso, algumas raças apresentam baixa congelabilidade. Foram inseminadas 104 éguas, divididas em dois experimentos, para avaliar a fertilidade do sêmen congelado de garanhões da raça Crioula (n=5), com 5% de dimetilformamida (DMF) ou 5% de glicerol (GLI), como crioprotetores. No Experimento I, as inseminações foram conduzidas pré-ovulação com sêmen fresco e criopreservado com DMF. No Experimento II, as éguas foram inseminadas pós-ovulação com sêmen fresco, DMF e GLI. As inseminações com sêmen congelado foram realizadas no ápice do corno uterino e as éguas do grupo controle foram inseminadas no corpo do útero com sêmen fresco. Para a avaliação  dos índices de prenhez dos grupos, utilizou-se um ciclo estral/animal. O diagnóstico de gestação foi realizado por meio de ultrassonografia transretal no 15º dia pós-ovulação. A motilidade média pós-descongelamento foi de 40% e 20%, respectivamente, para o sêmen congelado com DMF e GLI (P<0,05). Todos os garanhões tiveram motilidade superior no pós-descongelamento quando se utilizou a DMF. No Experimento I, o índice de prenhez foi de 12% (5/42) e 62% (20/32), respectivamente, para DMF e sêmen fresco (P<0,0001). No Experimento II, o índice de prenhez foi de 70% (7/10; P<0,05) para o sêmen fresco, 40% para o congelado com DMF (4/10; P<0,05) e 10% com GLI (1/10). A inseminação com sêmen congelado realizada com controle folicular mais frequente apresentou os melhores resultados. A baixa motilidade dos espermatozoides pós-descongelamento foi atribuída ao GLI utilizado no Experimento II. A DMF pode ser utilizada como uma alternativa ao congelamento do sêmen de garanhões da raça Crioula.

Pregnancy rates using stallions's frozen semen are variable; moreover, some breeds  present low freezability. One hundred and four (104) mares were inseminated and separeted into two experiments to evaluate fertility of frozen semens of Criollo stallions (n=5), with 5% of dimethylformamide (DMF) or 5% of glycerol (GLY) as cryoprotectants. In Experiment I, the inseminations were made during pre-ovulation with fresh and frozen semen with DMF. In Experiment II, the mares were inseminated during post-ovulation with fresh semen, DMF and GL. The inseminations with frozen semen were performed deep in the uterine horn ipsilateralis to the dominant follicle. Control mares were inseminated with fresh semen in the uterus. Only one estrus period per mare was used to evaluate the pregnancy rates of the groups. Pregnancy diagnosis through ultrasonography was performed on the 15th day post-ovulation. The mean post-thawing motility was 40% and 20%, respectively, for frozen semen with DMF and GLY (P<0.05). All stallions had higher post-thawing motility when using DMF. In Experiment I, pregnancy rates were 12% (5/42) and 62% (20/32), respectively for DMF and fresh semen (P<0.0001). In Experiment II, pregnancy rates were 40% (4/10), 10% (1/10) and 70% (7/10), respectively for DMF, GLY (P<0.05) and fresh semen (P<0.0001). Insemination with frozen semen performed with more frequent follicular control showed the best results. The low sperm motility after thawing was attributed to the GLY used in experiment II. The DMF can be used alternatively to Criollos Stallion’s semen feezing.

Asunto(s)

RESUMEN

O índice de prenhez utilizando sêmen criopreservado de garanhões é variável e, além disso, algumas raças apresentam baixa congelabilidade. Foram inseminadas 104 éguas, divididas em dois experimentos, para avaliar a fertilidade do sêmen congelado de garanhões da raça Crioula (n=5), com 5% de dimetilformamida (DMF) ou 5% de glicerol (GLI), como crioprotetores. No Experimento I, as inseminações foram conduzidas pré-ovulação com sêmen fresco e criopreservado com DMF. No Experimento II, as éguas foram inseminadas pós-ovulação com sêmen fresco, DMF e GLI. As inseminações com sêmen congelado foram realizadas no ápice do corno uterino e as éguas do grupo controle foram inseminadas no corpo do útero com sêmen fresco. Para a avaliação  dos índices de prenhez dos grupos, utilizou-se um ciclo estral/animal. O diagnóstico de gestação foi realizado por meio de ultrassonografia transretal no 15º dia pós-ovulação. A motilidade média pós-descongelamento foi de 40% e 20%, respectivamente, para o sêmen congelado com DMF e GLI (P<0,05). Todos os garanhões tiveram motilidade superior no pós-descongelamento quando se utilizou a DMF. No Experimento I, o índice de prenhez foi de 12% (5/42) e 62% (20/32), respectivamente, para DMF e sêmen fresco (P<0,0001). No Experimento II, o índice de prenhez foi de 70% (7/10; P<0,05) para o sêmen fresco, 40% para o congelado com DMF (4/10; P<0,05) e 10% com GLI (1/10). A inseminação com sêmen congelado realizada com controle folicular mais frequente apresentou os melhores resultados. A baixa motilidade dos espermatozoides pós-descongelamento foi atribuída ao GLI utilizado no Experimento II. A DMF pode ser utilizada como uma alternativa ao congelamento do sêmen de garanhões da raça Crioula.(AU)

Pregnancy rates using stallions's frozen semen are variable; moreover, some breeds  present low freezability. One hundred and four (104) mares were inseminated and separeted into two experiments to evaluate fertility of frozen semens of Criollo stallions (n=5), with 5% of dimethylformamide (DMF) or 5% of glycerol (GLY) as cryoprotectants. In Experiment I, the inseminations were made during pre-ovulation with fresh and frozen semen with DMF. In Experiment II, the mares were inseminated during post-ovulation with fresh semen, DMF and GL. The inseminations with frozen semen were performed deep in the uterine horn ipsilateralis to the dominant follicle. Control mares were inseminated with fresh semen in the uterus. Only one estrus period per mare was used to evaluate the pregnancy rates of the groups. Pregnancy diagnosis through ultrasonography was performed on the 15th day post-ovulation. The mean post-thawing motility was 40% and 20%, respectively, for frozen semen with DMF and GLY (P<0.05). All stallions had higher post-thawing motility when using DMF. In Experiment I, pregnancy rates were 12% (5/42) and 62% (20/32), respectively for DMF and fresh semen (P<0.0001). In Experiment II, pregnancy rates were 40% (4/10), 10% (1/10) and 70% (7/10), respectively for DMF, GLY (P<0.05) and fresh semen (P<0.0001). Insemination with frozen semen performed with more frequent follicular control showed the best results. The low sperm motility after thawing was attributed to the GLY used in experiment II. The DMF can be used alternatively to Criollos Stallions semen feezing.(AU)

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