RESUMEN

The two-step protocol (2 S) is currently used for boar semen cryopreservation. In this method, the cryoprotectant penetrant agents (CPAs) are added at 5 °C to reduce the toxicity of CPAs. An alternative is the one-step protocol (1 S), which is easier, cheaper, and reduces the necessity of equipment, but could increase the toxicity of CPAs. Currently, there are no studies that compared both protocols for boar semen cryopreservation. This experiment aimed to study the effect of cryopreservation protocol (1 S vs 2 S) on boar spermatozoa. In the one-step protocol, after centrifugation, the spermatozoa pellet was resuspended at 17 °C in the extender containing CPAs to achieve a concentration of 1 × 109 spermatozoa/mL and then submitted to cryopreservation. For the two-step protocol, the sperm pellet was resuspended in fraction A at 17 °C to achieve a concentration of 1.5 × 109 spermatozoa/ mL, and then allowed to cool to 5º C before fraction B with CPA was added to the sample to achieve a final concentration of 1 × 109 spermatozoa/mL and followed by freezing. The cryopreservation protocol did not impact total motility at 5 °C (1 S: 78.5 % vs 2 S: 79 %, p > 0.05). After thawing, the two-step protocol improved (p < 0.05) total (1 S: 18.2 % vs 2 S: 29.5 %) and progressive motility (1 S: 9 % vs 2 S: 15%). Further, the 2 S protocol increased (p < 0.05) the percentage of rapid spermatozoa (1 S: 8.7 % vs 2 S: 14.6 %) and spermatozoa with intact plasma and acrosomal membrane (IAIP) (1 S: 40.5 % vs 2 S: 61.5 %), and increased (p < 0.05) live sperm cells with high mitochondrial potential (MHIP) (1 S: 42.9 % vs 2 S: 60 %). The boar semen cryopreservation method (TRT) did not (p > 0.05) alter membrane lipid disorder, lipid peroxidation, and superoxide anion. Thus, the best method for boar semen cryopreservation is the two-step protocol.

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The study aimed to evaluate the supplementation of gilts with cow's milk naturally enriched with n-3 and n-6 polyunsaturated fatty acids (PUFA) on reproductive outcomes, and the serum biochemical and FA profile of swine females and their offspring. During 316 days, 30 gilts were distributed into three groups: (1) Control, fed a basal diet + milk from cows without oil; (2) n-3, fed a basal diet + milk from cows fed a diet enriched with linseed oil; (3) n-6, fed a basal diet + milk from cows fed a diet enriched with soybean oil. The gilts receiving the diets containing PUFA had higher serum urea and very-low-density lipoprotein levels and lower serum total protein and low-density lipoprotein levels compared to the Control group. Females supplemented with n-3 presented higher serum palmitic acid and γ-linolenic acid levels than those fed n-6. Piglets from the Control group were heavier at birth than those from females supplemented with enriched milk. The piglets from females receiving enriched milk had 140 g higher body weight from 1 to 21 days old compared to the Control group, and greater average daily weight gain from 7 to 14 days old. The serum eicosapentaenoic acid level of piglets fed n-3 was 69% higher than those fed n-6, which reduced the AA/EPA ratio. Gilts supplemented with PUFA-enriched cow's milk showed changes in their serum palmitic and γ-linolenic acid levels, in addition to improved performance, EPA concentration and consequently reduced AA/EPA ratio in their piglets, demonstrating beneficial results for their progeny.

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This study evaluated the effects of supplying altrenogest from day 6-12 of pregnancy on the endometrial glandular epithelium, corpora lutea (CL) morphology, and endometrial and CL gene expression. A total of 12 crossbred females (Landrace × Large White) were used. The females were assigned to 4 treatments according to a random design with a 2 × 2 factorial arrangement, with two categories (sow or gilt) and two treatments (non-treated and treated with altrenogest). On day 6 of pregnancy, animals were allocated to one of the following groups: non-treated (NT, n = 6; 3 sows and 3 gilts), and (T, n = 6; 3 sows and 3 gilts) treated daily with 20 mg of altrenogest, from day 6-12 of pregnancy. All animals were euthanized on day 13 of pregnancy. All CLs were individually weighed, and their volume were determined. The endometrial glandular density (GD), mean glandular area (MGA), and vascular density (VD) were determined by histomorphometric and immunohistochemical analyses. Endometrium samples were collected and analyzed by qRT-PCR to evaluate the abundance of transcripts for VEGF and IGF-I. Females in the T group had higher MGA (P < 0.05) compared to the NT group. There was no effect of treatment on GD or VD for both experimental groups. Sows in the T group had augmented expression of IGF-I (P < 0.05). Progestagen had no detrimental effect on CL morphology. In conclusion, altrenogest improves the uterine environment during the peri-implantation period in pigs without compromising corpora lutea development.

RESUMEN

This study evaluated the effects of supplying altrenogest from day 6-12 of pregnancy on the endometrial glandular epithelium, corpora lutea (CL) morphology, and endometrial and CL gene expression. A total of 12 crossbred females (Landrace × Large White) were used. The females were assigned to 4 treatments according to a random design with a 2 × 2 factorial arrangement, with two categories (sow or gilt) and two treatments (non-treated and treated with altrenogest). On day 6 of pregnancy, animals were allocated to one of the following groups: non-treated (NT, n = 6; 3 sows and 3 gilts), and (T, n = 6; 3 sows and 3 gilts) treated daily with 20 mg of altrenogest, from day 6-12 of pregnancy. All animals were euthanized on day 13 of pregnancy. All CLs were individually weighed, and their volume were determined. The endometrial glandular density (GD), mean glandular area (MGA), and vascular density (VD) were determined by histomorphometric and immunohistochemical analyses. Endometrium samples were collected and analyzed by qRT-PCR to evaluate the abundance of transcripts for VEGF and IGF-I. Females in the T group had higher MGA (P < 0.05) compared to the NT group. There was no effect of treatment on GD or VD for both experimental groups. Sows in the T group had augmented expression of IGF-I (P < 0.05). Progestagen had no detrimental effect on CL morphology. In conclusion, altrenogest improves the uterine environment during the peri-implantation period in pigs without compromising corpora lutea development.(AU)

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Seminal plasma (SP) plays a vital role in the maintenance of sperm function and integrity along with being involved in their communication with the female reproductive tract. Under in vitro conditions, although it is generally accepted that boar semen is better preserved when SP is diluted (extended) or removed (cryopreserved), its role during storage is not completely elucidated. In this context, the current study sought to determine the role of SP during storage of boar spermatozoa at 17 °C for 72 h. Thus, two treatments were prepared with semen from the sperm-rich fraction (SRF) of boar ejaculate previous to storage in liquid state: 1) PSP: semen directly extended in Beltsville Thawing Solution (BTS), and 2) ASP: semen first centrifuged with subsequent removal of supernatant (containing SP) followed by suspension of sperm in BTS. From this, two experiments were conducted separately in this work: 1) in vitro and 2) in vivo assays. The former aimed to evaluate how sperm capacity responds to in vitro capacitation (IVC) and whether their quality is affected by previous exposure to SP. In the latter, the objective was to understand how important these previous conditions can be for reproductive performance after artificial insemination (AI). According to our results, the previous removal of SP does not affect sperm quality and the response of these cells to IVC (P > 0.05) along with resulting in a lower percentage of acrosome damage in them [12.87 ±â€¯0.76 (ASP) vs. 16.38 ±â€¯0.73 (PSP)] (P < 0.05). This improved preservation of acrosome integrity in the absence of SP can explain the higher fertility rate (%) [63.27 ±â€¯23.47 (ASP) vs. 38.57 ±â€¯16.30 (PSP)] and number of implanted embryos at 28 days after AI (13.71 ±â€¯4.88 (ASP) vs. 7.16 ±â€¯4.02 (PSP)] (P < 0.05) presented by gilts inseminated with seminal doses of ASP. In conclusion, removal of SP prior to liquid storage of boar sperm for 72 h can be beneficial for their fertilizing ability.

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A inseminação artificial (IA) é uma biotécnica reprodutiva amplamente difundida dentro da cadeia suinícola. A mesma surge como uma alternativa para melhorar a eficiência reprodutiva aliada à rápida difusão de genética superior, o que consequentemente reflete sobre a produtividade dentro do sistema. Com o propósito de aperfeiçoar ainda mais a técnica de IA, o emprego de protocolos hormonais possibilita a sincronização de eventos como o estro e a ovulação, o que passa a fornecer condições para a realização da IA em um momento prédeterminado (IATF; inseminação artificial em tempo fixo). Neste manejo, a detecção do estro deixa de ser necessária, além de permitir a redução do número de doses inseminantes/estro/fêmea, bem como do número de mão de obra necessária. Além disso, a prática pode ser uma excelente alternativa para controlar o ciclo estral de fêmeas de reposição que precisam adentrar grupos de IA em datas pré-definidas dentro da granja. O resultado é o recrutamento e a preparação de um número de leitoas mais próximo ao real necessário, o que reduz os dias não produtivos (DNP) destas fêmeas dentro do sistema de produção e demais gastos associados à sua manutenção.

Artificial insemination (AI) is a reproductive biotechnology widely used within the pig breeding. It appears as an alternative to improve reproductive efficiency accompanied of the rapid diffusion of superior genetics, which consequently reflects on the productivity within the system. In order to further improve AI technique, the use of hormonal protocols allows the synchronization of events such as estrus and ovulation, which provides conditions for AI at a predetermined time (FTAI, fixed-time artificial insemination). In this management, estrus detection is no longer necessary, besides allowing the reduction of the number of seminal doses/estrus/female and of labor required. In addition, the practice may be an excellent alternative to control the estrus cycle of replacement gilts that need to enter AI groups at predefined dates within the farm. The result is the recruitment and preparation of a number of gilts closer to the real needed, which reduces non-productive days (NPD) of these females within the production system and other expenses associated with their maintenance.

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RESUMEN

A inseminação artificial (IA) é uma biotécnica reprodutiva amplamente difundida dentro da cadeia suinícola. A mesma surge como uma alternativa para melhorar a eficiência reprodutiva aliada à rápida difusão de genética superior, o que consequentemente reflete sobre a produtividade dentro do sistema. Com o propósito de aperfeiçoar ainda mais a técnica de IA, o emprego de protocolos hormonais possibilita a sincronização de eventos como o estro e a ovulação, o que passa a fornecer condições para a realização da IA em um momento prédeterminado (IATF; inseminação artificial em tempo fixo). Neste manejo, a detecção do estro deixa de ser necessária, além de permitir a redução do número de doses inseminantes/estro/fêmea, bem como do número de mão de obra necessária. Além disso, a prática pode ser uma excelente alternativa para controlar o ciclo estral de fêmeas de reposição que precisam adentrar grupos de IA em datas pré-definidas dentro da granja. O resultado é o recrutamento e a preparação de um número de leitoas mais próximo ao real necessário, o que reduz os dias não produtivos (DNP) destas fêmeas dentro do sistema de produção e demais gastos associados à sua manutenção.(AU)

Artificial insemination (AI) is a reproductive biotechnology widely used within the pig breeding. It appears as an alternative to improve reproductive efficiency accompanied of the rapid diffusion of superior genetics, which consequently reflects on the productivity within the system. In order to further improve AI technique, the use of hormonal protocols allows the synchronization of events such as estrus and ovulation, which provides conditions for AI at a predetermined time (FTAI, fixed-time artificial insemination). In this management, estrus detection is no longer necessary, besides allowing the reduction of the number of seminal doses/estrus/female and of labor required. In addition, the practice may be an excellent alternative to control the estrus cycle of replacement gilts that need to enter AI groups at predefined dates within the farm. The result is the recruitment and preparation of a number of gilts closer to the real needed, which reduces non-productive days (NPD) of these females within the production system and other expenses associated with their maintenance.(AU)

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Boar semen cryopreservation remains a challenge due to the extension of cold shock damage. Thus, many alternatives have emerged to improve the quality of frozen-thawed boar sperm. Although the use of seminal plasma arising from boar sperm-rich fraction (SP-SRF) has shown good efficacy; however, the majority of actual sperm evaluation techniques include a single or dual sperm parameter analysis, which overrates the real sperm viability. Within this context, this work was performed to introduce a sperm flow cytometry fourfold stain technique for simultaneous evaluation of plasma and acrosomal membrane integrity and mitochondrial membrane potential. We then used the sperm flow cytometry fourfold stain technique to study the effect of SP-SRF on frozen-thawed boar sperm and further evaluated the effect of this treatment on sperm movement, tyrosine phosphorylation and fertility rate (FR). The sperm fourfold stain technique is accurate (R2 = 0.9356, p > 0.01) for simultaneous evaluation of plasma and acrosomal membrane integrity and mitochondrial membrane potential (IPIAH cells). Centrifugation pre-cryopreservation was not deleterious (p > 0.05) for any analyzed variables. Addition of SP-SRF after cryopreservation was able to improve total and progressive motility (p < 0.05) when boar semen was cryopreserved without SP-SRF; however, it was not able to decrease tyrosine phosphorylation (p > 0.05) or improve IPIAH cells (p > 0.05). FR was not (p > 0.05) statistically increased by the addition of seminal plasma, though females inseminated with frozen-thawed boar semen plus SP-SRF did perform better than those inseminated with sperm lacking seminal plasma. Thus, we conclude that sperm fourfold stain can be used to simultaneously evaluate plasma and acrosomal membrane integrity and mitochondrial membrane potential, and the addition of SP-SRF at thawed boar semen cryopreserved in absence of SP-SRF improve its total and progressive motility.

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Reestablishment of testicular normal temperature after testicular heat stress is unknown and its effect varies widely. The aim of this study was to investigate the impact of scrotal insulation (IN) on testicular temperature and its relation to semen quality and testosterone blood serum concentration. For this, 33 rams were used; 17 submitted to IN for 72 hours (using bags involving the testes) and 16 not submitted to IN (control group). The experiment was performed between August and December 2013 in Pirassununga, Brazil (21°56″13″ South/47°28'24″ West). Seminal characteristics, testosterone blood serum concentration, rectal temperature (RT), respiratory frequency, scrotal superficies mean temperature (SSMT), and eye area mean temperature (EAMT) were analyzed 7 days before IN and 21, 35, 49, 63, and 90 days afterward. Scrotal superficies mean temperature and EAMT were measured by thermography camera FLIR T620. Testosterone was evaluated by radioimmunoassay. Analysis of variance was used to determine the main effects of treatment, time, and treatment-by-time interaction using PROC MIXED of SAS software adding command REPEAT. Pearson correlation test was used to verify correlation between SSMT, EAMT, RT, and respiratory frequency. Significant difference was considered when P ≤ 0.05. At the end of IN, SSMT was higher (P < 0.05) in insulated group (32.26 ± 0.19(o)C) than in control group (30.58 ± 0.18(o)C), and the difference between rectal and testicular (deduced from SSMT) temperatures was 1.12 °C; in the other times of the evaluation this difference was between 2.91 and 4.25 °C in IN group. Scrotal superficies mean temperature was reestablished 24 hours after IN. Rectal temperature and EAMT presented correlation (r = 0.59; P < 0.0001). There was time-by-treatment interaction for total sperm (P = 0.0038) and progressive motility (P = 0.01), abnormal spermatozoa (P < 0.0001), membranes integrity (P < 0.0001), induced thiobarbituric acid reactive substances (TBARSs; P = 0.05), and DNA integrity (P = 0.0004). These semen characteristics were negatively affected 21 days after IN, and excluding induced TBARSs and abnormalities, recovered 35 days afterward; induced TBARSs just were affected after 49 days of IN; sperm abnormalities just recovered after 63 days. Testosterone blood serum concentration was lesser in insulated rams (P = 0.03). Thus, the difference of 1.12 °C between RT and testicular temperature impacts semen quality and testosterone blood serum concentration. Moreover, this study shows that rams can recover testes temperature efficiently toward IN and that infrared thermography is an efficient tool to identify differences on SSMT.

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The aim of this study was to investigate the efficiency of low-level laser therapy (LLLT) to recovery testicular degeneration in rams. In the first study, rams were induced to testicular degeneration by scrotal insulation, and then, they were treated using LLLT at 28 J/cm(2) (INS28) or 56 J/cm(2) (INS56) energy densities. Sperm kinetics, morphology, and membranes integrity as well as proportion of lumen area in seminiferous tubule were assessed. In the second study, rams were submitted or not to scrotal insulation and treated or not by the best protocol of LLLT defined by experiment 1 (INS28). In this study were evaluated sperm kinetics, morphology, membranes integrity, ROS production, and DNA integrity. Testosterone serum concentration and proportion of lumen area in seminiferous tubule were also analyzed. Insulation was effective in promoting sperm injuries in both experiments. Biostimulatory effect was observed in experiment 1: INS28 presented smaller proportion of lumen area (P = 0.0001) and less degeneration degree (P = 0.0002). However, in experiment 2, there was no difference between the groups (P = 0.17). In addition, LLLT did not improve sperm quality, and there was a decreasing for total and progressive motility (P = 0.02) and integrity of sperm membranes (P = 0.01) in LLLT-treated groups. Moreover, testosterone concentration was not improved by LLLT (P = 0.37). Stimulation of aerobic phosphorylation by LLLT may have led to a deregulated increase in ROS leading to sperm damages. Thus, LLLT at energy of 28 J/cm(2) (808 nm of wavelength and 30 mW of power output) can induce sperm damages and increase the quantity of cells in seminiferous tubule in rams.

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Estrus stimulation by exogenous gonadotropins (EG) in association with dietary flushing is an important tool for theimprovement of gilt reproductive performance. However, there is evidence associating both flushing and EG with a disturbance in the endocrine balance that could lead to increased ovarian cysts. The aim of this study was to evalu- ate whether flushing or EG might affect the ovulation rate and the incidence of ovarian cysts. Seventy-one gilts were randomly distributed into 2x2 factorial design with four treatments: flushing and hormone (wFwH); no flushing and hormone (nFwH); flushing without hormone (wFnH); and neither flushing nor hormone (nFnH). Gilts were slaughtered for macroscopic and histopathological ovary examination approximately five days after AI. The characterization of these cysts was performed by optical microscopy in the following: follicular cysts (FC), luteinizedcysts (LC) or cystic corpora lutea (CCL). The number of ovulations did not differ between treatments. There was no interaction between the factors in any analyzed variable. The frequency of gilts with CCL and LC was not affected by flushing and EG. No difference was found in the incidence of FC, with 12.5% and 5.88% in gilts from wFwH and nFwH treatments, respectively. There were no differences in the proportion of CCL between FC and LC (9.85 vs. 4.22 and 4.22%, respectively). In conclusion, the use of exogenous gonadotropins for second estrus synchronization in gilts, either alone or in association with dietary flushing, does not increase the incidence of ovarian cysts, nor does it decrease the ovulation rate.(AU)

A estimulação do estro por gonadotrofinas exógenas (GE) associada ao flushing alimentar é uma ferramenta importante na melhoria do desempenho reprodutivo de marrãs. Contudo, há evidência da associação do flushing com GE levando ao desequilíbrio no sistema endócrino que poderia levar ao aumento de cistos ovarianos. O objetivo deste estudo foi avaliar se o flushing ou GE pode afetar a taxa de ovulação e a incidência de cistos ovarianos. Setenta e uma marrãs foramdistribuídas aleatoriamente em arranjo fatorial 2x2 com quatro tratamentos: flushing e hormônio (cFcH); sem flushing e com hormônio (sFcH); com flushing e sem hormônio (cFsH) e sem flushing e hormônio (sFsH). Marrãs foram abatidas para exame macroscópico e histopatológico dos ovários, aproximadamente cinco dias após IA. A caracterização desses cistos foi realizada por microscopia óptica: cistos foliculares (CF), cistos luteinizados (CL) ou corpos lúteos císticos(CCL). O número de ovulações não diferiu entre os tratamentos. Não houve interação entre os fatores em qualquer variável analisada. A frequência de leitoas com CCL e CL não foi afetada pelo flushing e GE. Não houve diferença na incidência de CF, com 12,5% e 5,88 % em leitoas dos tratamentos cFcH e sFcH, respectivamente. Não foram obtidas diferenças na proporção de CCL entre CF e CL (9,85 vs. 4,22 e 4,22%, respectivamente). Em conclusão, a utilização de gonadotrofinas exógenas para sincronização do segundo estro de marrãs, isoladamente ou em associação com o flushing, não aumenta a incidência de cistos ovarianos e não diminui a taxa de ovulação.(AU)

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The study evaluated the effect of dietary restriction in prepubertal gilts associated with the use of flushing in the preceding cycle of artificial insemination, 2nd or 3rd estrus on productive performance, number of corpora lutea and fetus, besides the fetus survival rate. A total of 96 gilts were distributed to a completely randomized design with 2x2x2 factorial arrangement of treatments, consisting of: nutritional strategy, ad libitum or restricted feeding, use or not of flushing in the preceding cycle AI, and time of AI, held on the 2nd or 3rd estrus. The age at which gilts expressed the 1st estrus was not influenced by nutritional strategy, but the body weight and weight gain were higher (P 0.05) in gilts submitted to ad libitum feeding. No interactions were observed as treatment effect on number of corpora lutea and fetus survival rate. The number of fetuses in females on ad libitum feeding was not influenced by time of AI, but the females feed restriction showed an increase (P 0.05) in the number of fetuses when inseminated on 3rd estrus. Thus, it is concluded that the use of ad libitum nutritional strategy allows for insemination forward 2nd estrus without reducing the number of fetuses, reducing the non-productive days gilt. However, this strategy reduces the rate of fetal survival until day 35 of gestation(AU)

Foi avaliado o efeito da restrição alimentar na fase pré-púbere associada ao emprego do flushing no ciclo precedente ao da inseminação artificial, sendo realizada no 2 ou 3 estro, sobre o desempenho produtivo, numero de corpos lúteos e de fetos, além da taxa de sobrevivência fetal. Um total de 96 fêmeas foi distribuído em delineamento inteiramente casualizado com arranjo fatorial 2x2x2, sendo considerados os fatores: estratégia nutricional, alimentação ad libitum ou restrita; utilização ou não de flushing no ciclo precedente a IA, e momento da IA, realizada no 2 ou 3 estro, constituindo oito tratamentos. A idade em que as marras manifestaram o 1 estro não foi influenciada pela estratégia nutricional, mas o peso e o ganho de peso foram maiores (P 0,05) na alimentação ad libitum. Não foram observados interação e tão pouco efeito de tratamento no numero de corpos lúteos e a taxa de sobrevivência dos fetos. O numero de fetos em fêmeas mantidas em alimentação ad libitum não foi influenciado pelo momento da IA, contudo as fêmeas em restrição alimentar apresentaram aumento (P 0,05) no numero de fetos quando inseminadas no 3 estro. Desse modo, conclui-se que o emprego da estratégia nutricional ad libitum possibilita adiantar a inseminação para o 2 estro sem redução no numero de fetos, diminuindo os dias não produtivos da marra. Porém, essa estratégia reduz a taxa de sobrevivência fetal até 35º dia de gestação(AU)

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RESUMEN

Estrus stimulation by exogenous gonadotropins (EG) in association with dietary flushing is an important tool for theimprovement of gilt reproductive performance. However, there is evidence associating both flushing and EG with a disturbance in the endocrine balance that could lead to increased ovarian cysts. The aim of this study was to evalu- ate whether flushing or EG might affect the ovulation rate and the incidence of ovarian cysts. Seventy-one gilts were randomly distributed into 2x2 factorial design with four treatments: flushing and hormone (wFwH); no flushing and hormone (nFwH); flushing without hormone (wFnH); and neither flushing nor hormone (nFnH). Gilts were slaughtered for macroscopic and histopathological ovary examination approximately five days after AI. The characterization of these cysts was performed by optical microscopy in the following: follicular cysts (FC), luteinizedcysts (LC) or cystic corpora lutea (CCL). The number of ovulations did not differ between treatments. There was no interaction between the factors in any analyzed variable. The frequency of gilts with CCL and LC was not affected by flushing and EG. No difference was found in the incidence of FC, with 12.5% and 5.88% in gilts from wFwH and nFwH treatments, respectively. There were no differences in the proportion of CCL between FC and LC (9.85 vs. 4.22 and 4.22%, respectively). In conclusion, the use of exogenous gonadotropins for second estrus synchronization in gilts, either alone or in association with dietary flushing, does not increase the incidence of ovarian cysts, nor does it decrease the ovulation rate.

A estimulação do estro por gonadotrofinas exógenas (GE) associada ao flushing alimentar é uma ferramenta importante na melhoria do desempenho reprodutivo de marrãs. Contudo, há evidência da associação do flushing com GE levando ao desequilíbrio no sistema endócrino que poderia levar ao aumento de cistos ovarianos. O objetivo deste estudo foi avaliar se o flushing ou GE pode afetar a taxa de ovulação e a incidência de cistos ovarianos. Setenta e uma marrãs foramdistribuídas aleatoriamente em arranjo fatorial 2x2 com quatro tratamentos: flushing e hormônio (cFcH); sem flushing e com hormônio (sFcH); com flushing e sem hormônio (cFsH) e sem flushing e hormônio (sFsH). Marrãs foram abatidas para exame macroscópico e histopatológico dos ovários, aproximadamente cinco dias após IA. A caracterização desses cistos foi realizada por microscopia óptica: cistos foliculares (CF), cistos luteinizados (CL) ou corpos lúteos císticos(CCL). O número de ovulações não diferiu entre os tratamentos. Não houve interação entre os fatores em qualquer variável analisada. A frequência de leitoas com CCL e CL não foi afetada pelo flushing e GE. Não houve diferença na incidência de CF, com 12,5% e 5,88 % em leitoas dos tratamentos cFcH e sFcH, respectivamente. Não foram obtidas diferenças na proporção de CCL entre CF e CL (9,85 vs. 4,22 e 4,22%, respectivamente). Em conclusão, a utilização de gonadotrofinas exógenas para sincronização do segundo estro de marrãs, isoladamente ou em associação com o flushing, não aumenta a incidência de cistos ovarianos e não diminui a taxa de ovulação.

Asunto(s)

RESUMEN

The study evaluated the effect of dietary restriction in prepubertal gilts associated with the use of flushing in the preceding cycle of artificial insemination, 2nd or 3rd estrus on productive performance, number of corpora lutea and fetus, besides the fetus survival rate. A total of 96 gilts were distributed to a completely randomized design with 2x2x2 factorial arrangement of treatments, consisting of: nutritional strategy, ad libitum or restricted feeding, use or not of flushing in the preceding cycle AI, and time of AI, held on the 2nd or 3rd estrus. The age at which gilts expressed the 1st estrus was not influenced by nutritional strategy, but the body weight and weight gain were higher (P 0.05) in gilts submitted to ad libitum feeding. No interactions were observed as treatment effect on number of corpora lutea and fetus survival rate. The number of fetuses in females on ad libitum feeding was not influenced by time of AI, but the females feed restriction showed an increase (P 0.05) in the number of fetuses when inseminated on 3rd estrus. Thus, it is concluded that the use of ad libitum nutritional strategy allows for insemination forward 2nd estrus without reducing the number of fetuses, reducing the non-productive days gilt. However, this strategy reduces the rate of fetal survival until day 35 of gestation...

Foi avaliado o efeito da restrição alimentar na fase pré-púbere associada ao emprego do flushing no ciclo precedente ao da inseminação artificial, sendo realizada no 2 ou 3 estro, sobre o desempenho produtivo, numero de corpos lúteos e de fetos, além da taxa de sobrevivência fetal. Um total de 96 fêmeas foi distribuído em delineamento inteiramente casualizado com arranjo fatorial 2x2x2, sendo considerados os fatores: estratégia nutricional, alimentação ad libitum ou restrita; utilização ou não de flushing no ciclo precedente a IA, e momento da IA, realizada no 2 ou 3 estro, constituindo oito tratamentos. A idade em que as marras manifestaram o 1 estro não foi influenciada pela estratégia nutricional, mas o peso e o ganho de peso foram maiores (P 0,05) na alimentação ad libitum. Não foram observados interação e tão pouco efeito de tratamento no numero de corpos lúteos e a taxa de sobrevivência dos fetos. O numero de fetos em fêmeas mantidas em alimentação ad libitum não foi influenciado pelo momento da IA, contudo as fêmeas em restrição alimentar apresentaram aumento (P 0,05) no numero de fetos quando inseminadas no 3 estro. Desse modo, conclui-se que o emprego da estratégia nutricional ad libitum possibilita adiantar a inseminação para o 2 estro sem redução no numero de fetos, diminuindo os dias não produtivos da marra. Porém, essa estratégia reduz a taxa de sobrevivência fetal até 35º dia de gestação...

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