T. Lucia

Risk factors for stillbirths in two swine farms in the south of Brazil.

We evaluated stillbirth risk factors in two commercial swine farms of the Rio Grande do Sul State (south of Brazil). The study was conducted during 1 month in Farm A and during 2 months in Farm B, both during 1999. Data for all farrowings that occurred during the study period were recorded (101 for Farm A and 373 for Farm B), without interference in the farm management. In Farm A, 39% of all litters born during the period of interest had stillborn piglets and the stillborn risk for piglets was 12%. In Farm B, 25% of all litters had stillborn piglets whereas the stillborn risk was 2%. Variables considered as potential risk factors for stillbirths were: parity (1, 2-3, 4+); breed (purebred or crossbred); sow body-condition (normal or fat); use of oxytocin during parturition (yes or no); obstetric intervention through vaginal palpation (yes or no); farrowing duration (<4 or > or =4h); mummified fetuses (yes or no); total litter size (<12 or > or =12 piglets); and litter birth weight (<11 or > or =11kg). All stillborn piglets had their classification validated by necropsy. In multivariable logistic-regressions, the cases were the litters having at least one stillborn piglet. In Farm A, litters having at least 12 pigs and in which oxytocin was used during the parturition had 20.8-times-higher odds of stillborn occurrence. In Farm B, litters from sows having parity > or =4 had 2.2-times-higher odds of stillborn occurrence than litters from parity 2 to 3 females, litters having > or =12 pigs had 2.0-times-higher odds of a stillborn piglet than smaller litters and farrowings in which vaginal palpation was performed had 8.0-times-higher odds. Farrowing room management to minimize stillborn risk should target higher-parity females, large litters and optimization of practices of obstetric interventions.

Use of amides as cryoprotectants in extenders for frozen sperm of tambaqui, Colossoma macropomum

Amides were tested as cryoprotectants in comparison with glycerol and DMSO (more traditional cryoprotectants) for recovery of Colossoma macropomum (tambaqui fish) sperm. Milt was extended in Beltsville Thawing Solution, then frozen with the addition of 2%, 5%, 8%, or 11% of: (1) dimethylacetamide (DMA), (2) dimethylformamide (DMF), (3) methylformamide (MF), or with 5% glycerol or 10% dimethylsulfoxide. Fertilization rates were greatest (P<0.001) with amides; 8% DMF (91.6±1.3%), 5% DMF (88.9±1.6%), and 8% MF (83.0±1.6%), which did not significantly differ among themselves, when compared with glycerol (51.6±2.4%) and DMSO (61.9±3.1%). The best hatching rates (P<0.001) also occurred for 5% or 8% DMF and 8% MF (79.1±3.1, 87.6±1.5, and 74.8±3.0, respectively) and were also similar (P>0.05). For such treatments, both fertilization and hatching rates were similar (P>0.05) to those with fresh sperm (91.7±1.4 and 87.4±1.4, respectively). The best sperm motility across extenders (at least 55.7%) was with 5%, 8%, and 11% DMF (P<0.001). Those same treatments, along with 11% MF, provided the longest (P<0.001) period of motility (at least 1 min). The greatest sperm integrity (more than 54%) was with 5% and 11% MF and with DMA and DMF at all tested concentrations (P<0.001). The greatest (P<0.001) sperm viability (at least 31%) was for 5%, 8%, and 11% DMA, and with 8% and 11% MF, and also for DMF at all tested concentrations. Sperm DNA integrity was best (more than 50%) for 2%, 5%, and 8% MF and for DMA and DMF at all concentrations (P<0.001), whereas 2% DMA, 11% MF, 11% DMF, and the three amides at both 5% and 8% yielded the highest mitochondrial functionality (at least 44%; P<0.001); thus, 8% MF and both 5% and 8% DMF were the cryoprotectants with the best postthaw quality for C. macropomum sperm.

Effect of low density lipoprotein on the quality of cryopreserved dog semen

Egg yolk is included in extenders for semen cryopreservation due to its protective effect against cold shock, which is attributed to the presence of low density lipoprotein (LDL). This study evaluates how semen quality is affected by using LDL as a replacement for egg yolk in extenders for cooled and frozen dog semen. In Experiment 1, semen was extended in TRIS-glucose at 5 degrees C, in four treatments: 20% egg yolk (T1); 6% (T2); 8% (T3); and 10% LDL (T4). Sperm motility and membrane integrity after 24, 48, 72 and 96 h and the 50% conservation rate of motile spermatozoa (50 M) were evaluated. The 50 M was less for T1 than for the other treatments (P<0.01), but T2-T4 did not differ (P>0.05). In Experiment 2, glycerol at 10% was included in the freezing extender, in treatments similar to those from Experiment 1. Sperm motility and membrane integrity did not differ for T2, T3 and T4 at any period in Experiment 1 and after thawing in Experiment 2 (P>0.05), but were greater for all LDL treatments than for T1 (P<0.01), in both experiments. Thus, LDL can replace egg yolk in the composition of the TRIS-glucose extender for cooled or frozen dog semen.

Reproductive performance of early-weaned female swine according to their estrus profile and frequency of artificial insemination.

We determined the estrus profile (weaning-to-estrus interval (WEI), estrus duration (ED), and frequency of estrus per detection period) in 184 female swine and estimated the effect of the WEI, ED and frequency of artificial insemination (AI) on farrowing rate (FR) and litter size. Estrus detection was done at 8:30 a.m. and 5:00 p.m. The WEI was categorized as short (<100 h), medium (100-120 h) and long (>120 h). The ED was categorized as short (<60 h), medium (60-72 h) and long (>72 h). Mean lactation length was 14.6 days, mean WEI was 124.5 h and mean ED was 69 h. In each weaning group, females received either one or two AI, following a breeding schedule based on the estrus profile. In single-mated females, Al was performed 36 h after the beginning of estrus. In double-mated females, the first AI was done 24 h after the beginning of estrus and the second AI occurred 12 h later. The period of estrus detection had no effect (P > 0.05) on WEI, ED, FR, total born (TB) and live born litter size (LB). Mean FR was 82.6%, mean TB was 10.0% and mean LB was 9.2%. Mean ED was shorter (P < 0.03) for females having medium and long WEI (67.0 and 65.4 h, respectively) than for those having short WEI (72.2 h). A linear regression analysis identified a weak (R2 = 0.02) but significant negative association between ED and WEI (P = 0.05). The WEI did not influence FR (P > 0.05). Total litter size for females having short WEI (9.4) was lower (P < 0.03) than for those having long WEI (10.4). Also, LB for females having medium and long WEI (9.7-9.8) was higher (P < 0.05) than for those having short WEI (8.7). AI frequency had no effect on FR (P > 0.05). TB and LB litter size were lower (P < 0.05) for single-mated females (9.6 and 9.0, respectively) than for double-mated females (10.7 and 9.6, respectively). Double Al was associated with higher subsequent litter size. However, breeding schedules based only on estrus profile may not be precise in determining ideal breeding time, since females having short WEI had the longest ED and produced the lowest litter size.

Cryopreservation of immature equine oocytes, comparing a solid surface vitrification process with open pulled straws and the use of a synthetic ice blocker

The objective was to evaluate the effect of three cryopreservation methods on the in vitro maturation (IVM) and membrane integrity (MIn) of immature equine oocytes. An open pulled straw (OPS) method, a novel solid surface vitrification (SSV) process, and the addition of a synthetic ice blocker were evaluated. Compared with the control group (N=269), the OPS (N=159) and the SSV (N=202) cryopreservation methods decreased both IVM (50.9 vs. 13.3 and 9.4%, respectively; P<0.001) and MIn (76.6 vs. 31.1 and 33.7%; P<0.001) of immature equine oocytes. However, inclusion of 0.1% ice blocker in the OPS vitrification process increased the rates of both IVM (30.5%; P<0.01) and MIn (45.8%; P<0.05) of the oocytes (N=59). Including 0.1% ice blocker in the SSV process improved the IVM rate (20.9%; P<0.05), whereas MIn remained compromised in this group (N=67). However, increasing the concentration of the ice blocker (to 1.0%) in the cryopreservation methods did not significantly improve rates of IVM. In conclusion, the addition of a synthetic ice blocker (0.1%) to both cryopreservation processes significantly increased rates of both IVM and MIn of immature equine oocytes cryopreserved by OPS.

Leptin and mitogen-activated protein kinase (MAPK) in oocytes of sows and gilts

Leptin is a modulator of oocyte maturation and follicular development in swine. The MAPK are serine/threonine kinases that act as signal transduction pathways in swine ovaries. This study evaluated the presence of leptin, activated MAPK ERK 1/2 and p38 in oocytes of primordial/primary, secondary and tertiary follicles of gilts and sows. Ovaries from ten gilts and ten sows were collected in an abattoir, fixed in 10% formalin and prepared with classical histology methods. For immunohistochemistry, slides were incubated with polyclonal antibodies anti-leptin, anti-phospho ERK1/2 MAPK and anti-phospho p38 MAPK. Leptin immuno-labeling and the presence of activated ERK 1/2 MAPK were more intense for oocytes of sows (P<0.05), whereas p38 MAPK was more active for oocytes of gilts (P<0.05). Although no differences in immunolabeling for leptin and p38 MAPK were observed for oocytes of gilts at distinct follicle developmental stages (P>0.05), immunolabeling was intense for oocytes of sows included in primordial/primary follicles (P<0.05). Thus, leptin and p38 MAPK may be important to start oocyte development.

In vitro penetration of swine oocytes by homologous spermatozoa: Distinct systems for gamete's co-incubation and oocyte's cryopreservation

In vitro penetration (IVP) of swine oocytes by homologous spermatozoa was evaluated in two experiments using four boars as semen donors. In experiment 1, the IVP rate and the number of penetrating spermatozoa (PSP) were compared using three co-incubation systems for vitrified oocytes and fresh sperm: (1) 35mL petri dishes in a CO(2) incubator, (2) 35mL petri dishes in bags (submarine system) and (3) glass flasks partially submerged in water bath with the same gas mixture used for the bag system. Mean PSP was 8.2+/-10.1 and the IVP rate was 90.5%. The PSP differed across all systems (P=0.0006): 15.5+/-0.5 for flasks, 6.3+/-0.4 for CO(2), and 3.9+/-0.4 for bags. The IVP rate for flasks (95.0%) was greater (P=0.01) than for CO(2) and bags (90.8% and 85.0%, respectively), but it did not differ between flasks and CO(2) for three boars (P>0.05). In experiment 2, co-incubation was done as described for glass flasks in experiment 1. The IVP rate and PSP were compared for cryopreserved oocytes: either vitrified in open pulled straws (OPS), or frozen in cryotubes. Mean PSP was 5.4+/-6.5 and IVP rate was 89.6%. Both PSP and IVP rate were greater (P<0.0001) for oocytes frozen in cryotubes (7.0+/-0.3% and 95.8%, respectively) than those frozen in OPS (3.7+/-0.3% and 83.4%, respectively), with no differences found for three boars (P>0.05). In summary, successful IVP of swine oocytes by homologous spermatozoa can be achieved using gametes incubated in glass flasks and oocytes frozen in cryotubes.

Efeito de diferentes profundidades de cama sobre parâmetros ambientais para suínos em crescimento e terminação

Due to the large animal inventories and the great volume of waste, swine production is considered a highly polluting activity. Therefore one of its greatest challenges is the development of alternative production systems with lower polluting potential. Deep litter systems may be feasible alternative for waste management due to their capacity for slurry absorption, although they may negatively influence the thermal comfort of the pigs. The objective of this study was to evaluate the effect of distinct depths of rice husk litters used to raise pigs in growing and finishing phases on ambiental temperature and relative humidity inside the barn. Three treatments were compared: litter with a depth of 0.5 m; litter with a depth of 0.25 m; and solid concrete floor. Ambiental temperature and relative humidity inside the barn were not influenced by the use of litter or by different litter depths.

Brilliant cresyl blue staining negatively affects mitochondrial functions in porcine oocytes

The aim of the present study was to examine the effects of brilliant cresyl blue (BCB) staining on mitochondrial functions in porcine oocytes. Cumulus-oocyte complexes (COCs) collected from slaughterhouse-derived porcine ovaries were cultured with (13 μM) or without (0 μM, control) BCB for 60 min. Mitochondrial functions in oocytes were examined immediately after staining or after in vitro maturation. The BCB-stained oocytes produced reactive oxygen species (ROS) at higher levels than control oocytes immediately after staining (2.2-fold, P < 0.001) and after maturation (1.7-fold, P < 0.001). The adenosine triphosphate (ATP) content and mitochondrial membrane potential (MMP) in oocytes were similar for the two groups immediately after staining. However, ATP and relative MMP levels were significantly (P < 0.05) lower in BCB-treated oocytes than in the control (2.18 versus 2.83 pM and 0.82 versus 1.0, respectively). There was no difference in mitochondrial DNA copy number between the two groups after maturation. The ATP content in early developmental stage embryos (3 days after parthenogenetic activation) was lower in the BCB-stained group than that in the control group but the difference was not significant. In conclusion, BCB staining of oocytes at the immature stage compromises mitochondrial functions throughout oocyte maturation, but function is restored during early embryo development.

Association between the presence of protein bands in ram seminal plasma and sperm tolerance to freezing.

This study evaluated associations between the presence of protein bands in ram seminal plasma and the quality of sperm frozen with distinct extenders. Ejaculates were frozen in a Tris-egg yolk based extender, including either 5% glycerol or 100mM trehalose. Seminal plasma samples were submitted to unidimensional electrophoresis. Pre-freezing and post-thawing sperm quality was similar between extenders (P>0.05). A total of 26 bands were identified in ram seminal plasma. Pre-freezing sperm motility was increased when the 15, 19 and 80kDa bands were present in seminal plasma (P<0.05). The presence of an 11kDa band in seminal plasma was associated with reduced pre-freezing membrane integrity (P<0.05). After thawing, both sperm motility and membrane integrity were reduced when a 24kDa band was present in seminal plasma (P<0.05). Post-thawing acrosome integrity was greater in the presence of a 31kDa band in seminal plasma (P<0.05). Regardless of the cryoprotectant included in the freezing extender, these six bands may be potential markers for ram sperm tolerance to freezing.