Microplastic concentrations in cultured oysters in two seasons from two bays of Baja California, Mexico.

As filter feeders, bivalve mollusks have a high potential risk of contamination by microplastics (MPs), which can be considered a transfer vector for humans through their consumption. Spatial-temporal differences in the MP concentration were evaluated in the cultured oyster Magallana gigas in Todos Santos Bay (TSB) and San Quintin Bay (SQB) during winter and summer (2019). MPs were found in all samples in both seasons, where microfibers were the most abundant particles observed.

Microplastics: Sources and distribution in surface waters and sediments of Todos Santos Bay, Mexico.

Microplastics (MPs) are ubiquitous and a threat to marine and freshwater environments. Effluent waters from secondary wastewater treatment plants (WWTPs) into Todos Santos Bay (TSB) were investigated as sources of MPs. MPs were detected in all analyzed matrices and presented variable morphologies.

Porcine blastocyst viability and developmental potential is maintained for 48 h of liquid storage at 25 °C without CO gassing.

Short- and medium-term storage of pig embryos has become relevant for commercial application of non-surgical deep uterine embryo transfer (NsDU-ET) in the light of the strict legal and administrative requirements posed by the International Association for Air Transport (IATA) to allow shipment of liquid nitrogen (LN) containers and the technical drawbacks when using vitrified embryos. Therefore, this study developed an efficient method for the liquid storage of in vivo-derived porcine blastocysts for a moderate duration (48 h) without controlled CO gassing. We evaluated two storage temperatures (25 °C and 37 °C) and three HEPES-supplemented media: the chemically defined media TL-PVA and NCSU-PVA and the semi-defined medium NCSU-BSA.

Simple storage (CO-free) of porcine morulae for up to three days maintains the in vitro viability and developmental competence.

The advancement of porcine embryo transfer (ET) technology is constrained by regulatory hurdles (liquid nitrogen transportation) or, more importantly, the technical obstacles of using vitrified embryos in combination with nonsurgical deep uterine ET technology. Maintaining embryos in culture during transport and prior ET collides with the need of CO gassing and the best choice of culture medium. In this work, we describe storage conditions for short-term embryo CO-free storage that allowed for a majority of in vivo-derived porcine morulae to survive after 3 days of storage in a liquid state, and to develop to the blastocyst stage unhatched, a sanitary prerequisite for ET.

Organochlorine pesticides in residential soils and sediments within two main agricultural areas of northwest Mexico: Concentrations, enantiomer compositions and potential sources.

The agricultural Mexicali and Yaqui valleys (MV, YV) in northwest Mexico were heavily treated with organochlorine pesticides in the past. Residential soils and agricultural drain sediments were sampled in 2008-2009 and analyzed for DDTs (o,p'- and p,p'- isomers of DDE, DDD and DDT); hexachlorocyclohexanes (α-, β-, γ- and δ-HCH) and chlordanes (trans-chlordane, cis-chlordane, heptachlor and heptachlor exo-epoxide). Geometric means (GMs) (ng g dry weight) were: MV soils (n = 27) ΣDDT 22, ΣHCH 0.

Nonsurgical deep uterine transfer of vitrified, in vivo-derived, porcine embryos is as effective as the default surgical approach.

Surgical procedures are prevalent in porcine embryo transfer (ET) programs, where the use of vitrified embryos is quasi non-existent. This study compared the effectiveness of surgical vs nonsurgical deep uterine (NsDU) ET using vitrified, in vivo-derived embryos (morulae and blastocysts) on the reproductive performance and welfare of the recipients. The recipient sows (n=122) were randomly assigned to one of the following groups: surgical ET with 30 vitrified-warmed embryos (S-30 group, control); NsDU-ET with 30 vitrified-warmed embryos (NsDU-30 group) and NsDU-ET with 40 vitrified-warmed embryos (NsDU-40 group).

Successful non-surgical deep uterine transfer of porcine morulae after 24 hour culture in a chemically defined medium.

Excellent fertility and prolificacy have been reported after non-surgical deep uterine transfers of fresh in vivo-derived porcine embryos. Unfortunately, when this technology is used with vitrified embryos, the reproductive performance of recipients is low. For this reason and because the embryos must be stored until they are transferred to the recipient farms, we evaluated the potential application of non-surgical deep uterine transfers with in vivo-derived morulae cultured for 24 h in liquid stage.

An earlier uterine environment favors the in vivo development of fresh pig morulae and blastocysts transferred by a nonsurgical deep-uterine method.

This study aimed to evaluate the effect of recipient-donor estrous cycle synchrony on recipient reproductive performance after nonsurgical deep-uterine (NsDU) embryo transfer (ET). The transfers (N=132) were conducted in recipients sows that started estrus 24 h before (-24 h; N=9) or 0 h (synchronous; N=31), 24 h (+24 h; N=74) or 48 h (+48 h; N=18) after the donors. A total of 30 day 5 morulae or day 6 blastocysts (day 0=onset of estrus) were transferred per recipient.

A decadal trend study (1998-2008) of POPs in marine sediments at the south of the Southern California Bight.

In this study we present a temporal analysis of two groups of persistent organic pollutants. We compare dichlorodiphenyltrichloroethane (DDT) collected in coastal sediment samples during 1998 and 2008 at the southern end of the Southern California Bight. Other group of organochlorine compounds (OCs) compared in this decadal analysis is the polychlorinated biphenyls (PCBs).

The effects of superovulation of donor sows on ovarian response and embryo development after nonsurgical deep-uterine embryo transfer.

This study aimed to evaluate the effectiveness of superovulation protocols in improving the efficiency of embryo donors for porcine nonsurgical deep-uterine (NsDU) embryo transfer (ET) programs. After weaning (24 hours), purebred Duroc sows (2-6 parity) were treated with 1000 IU (n = 27) or 1500 IU (n = 27) of eCG. Only sows with clear signs of estrus 4 to 72 hours after eCG administration were treated with 750 IU hCG at the onset of estrus.

Relevance of ovarian follicular development to the seasonal impairment of fertility in weaned sows.

A field study was conducted to estimate seasonal differences in follicular development in weaned sows and to evaluate the implication of these differences on seasonal infertility. A total of 110 sows were selected at weaning during winter-spring (WS, n=58) and summer-autumn (SA, n=52). Ovaries were scanned once daily from weaning to the onset of oestrus and twice daily from then until ovulation.

Successful laparoscopic insemination with a very low number of flow cytometrically sorted boar sperm in field conditions.

The aim of this study was to develop a useful procedure for laparoscopic insemination (LI) with sex-sorted boar spermatozoa that yields adequate fertility results in farm conditions. In experiment 1, we evaluated the effects of single (oviducts) and double (oviducts and tips of the uterine horns) LI with X-sorted sperm on the reproductive performance of sows. Sows (N = 109) were inseminated once as follows: (1) single LI with 0.

Forskolin improves the cryosurvival of in vivo-derived porcine embryos at very early stages using two vitrification methods.

This study was aimed to determine the effect of forskolin on the viability of in vivo-derived porcine embryos vitrified by the superfine open pulled straw (SOPS) or solid surface vitrification (SSV) methods at the 2-cell, 4-cell, and blastocyst stages. Zygotes, 2- to 4-cell embryos, and morulae were obtained from superovulated sows. After collection, embryos were cultured for 24h with 0 or 10 μM forskolin and then vitrified using the SOPS and SSV method, or not vitrified (fresh controls).

Effect of MEM vitamins and forskolin on embryo development and vitrification tolerance of in vitro-produced pig embryos.

The aims of this study were (1) to determine the effect of in vitro maturation (IVM) medium supplementation with MEM vitamins on in vitro embryo development and sensitivity to vitrification of Day 6 blastocysts and (2) to evaluate whether the addition of forskolin to in vitro culture (IVC) medium enhances blastocyst survival following Super Open Pulled Straw (SOPS) vitrification. Cumulus-oocyte complexes (COCs; n=4000) were matured with 0.0% or 0.

The in vitro and in vivo developmental capacity of selected porcine monospermic zygotes.

In this study, we evaluated the in vitro and in vivo developmental capacity of selected monospermic zygotes produced in vitro. Cumulus-oocyte complexes were matured in vitro and inseminated with frozen-thawed spermatozoa. Thirteen hours after insemination, presumptive zygotes were centrifuged at 15,000 ×g for 20 minutes to polarize the lipids in the cytoplasm and permit the visualization of pronuclei.

Effects of lipid polarisation on survival of in vivo-derived porcine zygotes vitrified by the superfine open pulled-straw method.

This study aimed to evaluate the post-warming in vitro viability of intact porcine zygotes vitrified using the superfine open pulled-straw (SOPS) method and to investigate whether cryotolerance is increased by lipid polarisation before vitrification. In vivo-derived zygotes (n=317) were either untreated before SOPS vitrification or subjected to one of the following pre-treatments: (1) centrifugation (20 min, 15000 g) or (2) equilibration in high-osmolality medium (6 min, 400 mOsm kg(-1)) followed by centrifugation. Vitrified-warmed and non-vitrified fresh zygotes were cultured in vitro for 120 h.

Non-surgical deep intrauterine transfer of superfine open pulled straw (SOPS)-vitrified porcine embryos: evaluation of critical steps of the procedure.

Previous trials achieved extremely poor results when using the one-step warming method in a syringe in combination with non-surgical deep intrauterine transfer (NET) of superfine open pulled straw (SOPS)-vitrified embryos. This study aimed to assess the effect of the warming procedure on the in vitro and in vivo development of SOPS-vitrified embryos. The effect of the passage of the vitrified-warmed (VW) embryos through the NET catheter was also evaluated.

Exposure of in vitro-matured porcine oocytes to SYBR-14 and fluorescence impairs their developmental capacity.

Staining with Hoechst 33342 followed by ultraviolet irradiation is frequently used to aid or confirm the enucleation of recipient oocytes in porcine somatic cell nuclear transfer programs. However, the procedure has a clearly deleterious effect on the developmental ability of oocytes. This study evaluated the effectiveness of a longer-wavelength fluorochrome (SYBR-14) for visualizing maternal chromosomes in in vitro-matured porcine oocytes and the effects of this dye in combination with fluorescence excitation on the subsequent in vitro fertilization and embryo development of the oocytes.

Early developing pig embryos mediate their own environment in the maternal tract.

The maternal tract plays a critical role in the success of early embryonic development providing an optimal environment for establishment and maintenance of pregnancy. Preparation of this environment requires an intimate dialogue between the embryo and her mother. However, many intriguing aspects remain unknown in this unique communication system.

Effects of Hoechst 33342 staining and ultraviolet irradiation on the developmental competence of in vitro-matured porcine oocytes.

Hoechst 33342 (H342) in combination with ultraviolet (UV) irradiation is frequently used to assist the enucleation of porcine oocytes in somatic cell nuclear transfer programs. This work evaluated the effects of H342 (5 μg/mL for 12 min) staining and/or exposure to UV irradiation on fertilisability and developmental capacity of porcine oocytes matured in vitro. In Experiment 1, a total of 1388 mature oocytes were distributed in the following groups: Group 1: oocytes without treatment (Control), Group 2: oocytes stained with H342, Group 3: oocytes stained with H342 and UV irradiated for 30 sec, and Group 4: oocytes UV irradiated for 30 sec.

Use of polarized light microscopy in porcine reproductive technologies.

The meiotic spindle in the oocyte is composed of microtubules and plays an important role during chromosome alignment and separation at meiosis. Polarized light microscopy (PLM) could be useful for a non-invasive evaluation of the meiotic spindle and may allow removal of nuclear structures without fluorochrome staining and ultraviolet exposure. In this study, PLM was used to assess its potential application in porcine reproductive technologies.

Capability of frozen-thawed boar spermatozoa to sustain pre-implantational embryo development.

The present study was designed to evaluate the competence of frozen-thawed (FT) boar spermatozoa on the developmental ability of early porcine embryos under in vitro and in vivo conditions. Repeat deep uterine insemination was applied to sows (n=12) at 30 h and 36 h after estrus detection, using either 750 x 10(6) of liquid or FT motile spermatozoa in a volume of 5 mL. Semen was pooled from mature Pietrain boars (n=3) of proven fertility and classified as "good sperm freezers" in previous experiments.

In vitro postwarming viability of vitrified porcine embryos: effect of cryostorage length.

Porcine embryos, which had been vitrified and stored in liquid nitrogen for up to three yr, were retrospectively analyzed to evaluate the influence of duration of storage on their in vitro viability post-warming. All embryos were vitrified (OPS or SOPS) and warmed (three-step or direct warming) using procedures that resulted in the same in vitro survival, hatching rates, and numbers of cells. Therefore, embryo data obtained using the different procedures were pooled according to their developmental stage as morulae (n = 571) or blastocysts (n = 797) and to the length of their storage in liquid nitrogen: a) 1-9 d; b) 10-30 d; c) 31-90 d; d) 1-3 yr.

Superfine open pulled straws vitrification of porcine blastocysts does not require pretreatment with cytochalasin B and/or centrifugation.

The present study investigated the in vitro development of and cytoskeletal disruption suffered by in vivo-derived porcine blastocysts subjected to superfine open pulled straws (SOPS) vitrification. Blastocysts were either untreated prior to SOPS vitrification or were subjected to one of the following three pretreatment protocols: (1) centrifugation (12 min, 13 000g); (2) 25 min equilibration with 7.5 microg mL(-1) cytochalasin B; or (3) equilibration with cytochalasin B followed by centrifugation.

Vitrification and warming of in vivo-derived porcine embryos in a chemically defined medium.

The aim of this study was to design a protocol for vitrification and warming of porcine embryos in a chemically defined medium. A total of 663 morulae and blastocysts were collected from weaned crossbred sows (Large White-Landrace) 5 to 6 d after estrus and vitrified with the Superfine Open Pulled Straw method. In Experiment 1, embryos were vitrified using as a basic medium TCM-199-HEPES supplemented with 20% newborn calf serum (NBCS) or with 0, 0.