LPS-induced sickness behavior is not affected by selenium but is switched off by psychogenic stress in rats

Veterinary Research Communications - Sickness behavior (SB) is considered part of the adaptive behavioral and neuroimmune changes that occur in response to inflammatory processes. However, SB is a...     

In vitro evaluation of cryopreserved bovine sperm and its relation to field fertility in fixed‐time artificial insemination

This study aimed to assess characteristics of bovine cryopreserved sperm and evaluate its relation to field fertility in fixed‐time artificial insemination (FTAI). Semen samples of 16 bulls were used to inseminate 811 Nellore cows, and four of these bulls were also used to inseminate 101 Nellore heifers. Samples of the same ejaculate used for FTAI from each bull were analysed in the laboratory after thawing. Sperm motility and vigour were subjectively assessed by light microscope, and integrity of the plasma and acrosome membranes, and H₂O₂ production were evaluated by flow cytometer. Relation among sperm characteristics and pregnancy rate of cows and heifers were evaluated by univariate and multivariate logistic regression. Subjective sperm motility and vigour did not affect the probability of pregnancy in cows or heifers. In univariate analysis for pregnancy in cows, sperm traits related to acrosome injury positively affected probability of pregnancy mainly when associated with plasma membrane integrity; H₂O₂ production seems to be less important than plasma membrane integrity in affecting probability of pregnancy. In multivariate analysis, sperm traits related to injured acrosome positively affected probability of cow and heifer pregnancies while intact acrosome was negatively related to cow pregnancy. Intact plasma membrane and high H₂O₂ production were positively related to cow pregnancy but negatively related to heifer pregnancy. Results suggest that a capacitation‐like status of the acrosome may benefit probability of pregnancy in cows.     

Early luteal development in Santa Inês ewes superovulated with reduced doses of porcine follicle‐stimulating hormone

The aim was to compare the early luteal development in ewes superovulated with different doses of pFSH. Twenty‐nine Santa Inês ewes received a progesterone device (CIDR®) for 8 days. Gonadotrophic treatment started on Day 6: G200 (control, n = 9, 200 mg); G133 (n = 10, 133 mg); and G100 (n = 10, 100 mg of pFSH). On Day 6, all females received eCG (300 IU). B‐mode and spectral Doppler ultrasonography were performed daily during the early luteal phase (Days 11–15) to monitor the development of corpora lutea (CLs; dimensions) and ovarian arteries indices. CLs were also classified as normal or prematurely regressed (PRCL) on Day 15 by videolaparoscopy. Ewes from G100 and G133 showed gradual increase in luteal diameter during the early luteal phase (p < 0.001), whereas G200 animals presented increase from Day 11 to Day 13, and then decrease on Days 14 and 15 (p < 0.001). The G200 females showed greater percentage of PRCL (45.20%) than those of the other groups (p < 0.001). The normal CLs number was greater in G100 than in G133 (p = 0.04), while the PRCL number was greater in G200 than in the other groups (p = 0.03). Resistive index (RI) was greater in G200 than in G100 (p = 0.02). RI was lower in Day 12 than Day 15 (p = 0.02). Pulsatility index (PI) was greater on Days 14 and 15 (p < 0.01). In conclusion, the lowest dose of pFSH (100 mg) can be considered sufficient for an efficient superovulatory response in sheep, producing better CLs development dynamic in early luteal phase and ovarian blood perfusion and smaller number of PRCL than the traditional (200 mg) pFSH dose.     

Different levels of selenomethionine on the meat quality and selenium deposition in tissue of finishing pigs

The aim of the study was to verify the influence of selenomethionine (SM) supplementation on performance, carcass yield, characteristics of meat quality and Se tissue deposition of finishing pigs. A total of 128 hybrid pigs with an average weight of 76 kg were distributed in randomized blocks according to body weight in eight treatments and eight replicates. The experimental treatments were two Se levels from sodium selenite‐SS (0.3 and 0.6 ppm), four Se levels from SM (0.3, 0.4, 0.5 and 0.6 ppm) and two combinations of SS with SM (SS 0.15 + SM 0.15 ppm and SS 0.3 + SM 0.3 ppm) providing 0.3 and 0.6 ppm Se in the diet respectively. The feeds were based on corn and soya bean meal. After 30 days on test, were analysed the performance indices and the pigs were slaughtered at commercial slaughterhouse. The cold carcass yield, the physicochemical characteristics of the loin meat and the Se content in muscle and liver were evaluated. There was no significant difference in performance indices (p > .05); however, there was a linear effect on the increase in pig carcass yield by increasing SM (p < .05). The use of SM solely or combined with SS provided higher Se deposition in muscle compared to SS (p < .05). The highest Se deposition in muscle occurred for SM at 0.4 ppm (p < .05). The SS provided higher Se deposition in liver (p < .05). The SM presented best results for meat quality compared to other sources (p < .05). The level of 0.4 ppm Se promoted the best results for the indices of yellow, luminosity, cooking loss and pH (p < .05). The use of SM at any level promotes higher oxidation stability of pig meat (p < .05). The supplementation of SM at a level of 0.4 ppm promotes better physicochemical characteristics and higher Se deposition on swine meat.     

Effect of human tubal fluid medium and hyperactivation inducers on stallion sperm capacitation and hyperactivation

Conventional in vitro fertilization has not yet been implemented in the equine species. One of the main reasons has been the inability to develop a culture medium and incubation conditions supporting high levels of stallion sperm capacitation and hyperactivation in vitro. Although different culture media have been used for this purpose, human tubal fluid (HTF) medium, widely used in the manipulation of human and mice gametes, has not been reported so far in stallion sperm culture. The first part of this study aimed to compare HTF and Whitten's media on different stallion sperm quality and capacitation variables. Additionally, the effect of procaine, aminopyridine and caffeine in both media was evaluated on sperm motility parameters at different incubation times. Integrity and destabilization of the plasma membrane were evaluated by merocyanine 540/SYTOX Green (MC540), mitochondrial membrane potential (?Ψm) using tetramethylrhodamine methyl ester perchlorate (TMRM), acrosome membrane integrity by PNA/FITC and tyrosine phosphorylation by P‐tyrosine mouse mAb conjugated to Alexa Fluor® by flow cytometry. Motility parameters were evaluated using the integrated semen analysis system (ISAS®). We found no differences between Whitten's and HTF media and incubation time in terms of sperm viability, uninduced acrosome membrane damage or mitochondrial membrane potential at 30‐ and 120‐min incubation. Membrane fluidity (MC540) increased in both media at 30‐ and 120‐min incubation compared to noncapacitating conditions. Similarly, tyrosine phosphorylation increased in both media in capacitating conditions at 2‐ and 4‐hr incubation compared to noncapacitating conditions. Although procaine showed the best result in terms of sperm hyperactivated motility in both media, aminopyridine also showed parameters consistent with the hyperactivation including an increase in curvilinear velocity and decrease in straightness. In conclusion, HTF medium and aminopyridine equally support capacitation‐related parameters in stallion sperm.     

Combined treatment with oestradiol benzoate,d‐cloprostenol and oxytocin permits cervical dilation and nonsurgical embryo recovery in ewes

This study examined the feasibility of transcervical embryo recovery after the hormonal treatment to induce cervical dilation, following the 7‐day oestrous synchronization protocol in multiparous Santa Inês ewes. A total of 23 cyclic ewes received two doses of 37.5 μg of d‐cloprostenol by latero‐vulvar route 7 days apart. After the second injection of d‐cloprostenol, the ewes were checked for oestrus (every 12 hr) and then mated by fertile rams throughout the oestrous period. All ewes received 37.5 μg of d‐cloprostenol (latero‐vulvar) and 1 mg of oestradiol benzoate by either intramuscular (EBim group; n = 12) or intravaginal (EBivg group; n = 11) route 16 hr before embryo flushing. Twenty minutes before the flushing, 50 IU of oxytocin were administered intravenously. The oestrous response (i.e., the percentage of ewes that showed signs of oestrous behaviour after the second d‐cloprostenol injection) was 91.3% (21/23). The proportion of successfully penetrated ewes (81.8% compared with 80.0%), the mean duration of embryo flushing (24.7 ± 2.0 min compared 26.2 ± 1.9 min), the flushing fluid recovery rate (94.8 ± 1.3% compared with 91.0 ± 2.9%) and the average number of structures recovered per ewe (0.5 ± 0.4 compared with 0.8 ± 0.4) did not vary (p > 0.05) between the EBim and EBivg groups. Viable embryos were recovered from 41.2% (7/17) of successfully penetrated ewes. It can be concluded that nonsurgical (i.e., transcervical) embryo collection can be performed in oestrous‐synchronized Santa Inês ewes pretreated with d‐cloprostenol, oxytocin and oestradiol benzoate, with the latter hormone administered by either the intramuscular or intravaginal route.     

Effect of red propolis extract isolated or encapsulated in nanoparticles on the in vitro culture of sheep preantral follicle: Impacts on antrum formation,mitochondrial activity and glutathione levels

This study aimed to characterize the hydroethanolic extract of red propolis (HERP) and nanoparticles containing HERP for using as an additive in the culture medium of isolated ovine preantral follicles. HERP was characterized by high‐performance liquid chromatography (HPLC) and determination of flavonoid content, and the nanoparticles by the mean particle diameter, polydispersity index (PI) and encapsulation efficiency (EE). The effect of HERP (10 and 20 ηg/ml—HERP10 and HERP20 groups) and nanoparticles (NP10 and NP20 groups) on isolated secondary follicles cultured in vitro for 12 days was observed by morphological evaluation, oxidative stress markers (reactive oxygen species—ROS and glutathione—GSH) and active mitochondria. HPLC showed formononetin as the major compound in the HERP (63.92 ± 0.21 μg/mL). The content of flavonoids ranged from 2.14% to 11.00%. The nanoparticles showed mean diameter of 287.5 ± 3.9 and 479 ± 18.1 ηm; PI of 0.117 ± 0.018 and 0.316 ± 0.039; and EE of 67.15% and 41%, respectively, for the NP10 and NP20 groups. After 12 days of culture, HERP20 and NP20 increased (p < 0.05) the percentage of normal follicles compared to NP10. HERP20 showed significantly higher percentages of antrum formation than control medium (MEM) and NP10 (p < 0.05). HERP20 also showed an increase (p < 0.05) in mitochondrial activity compared to the other treatments, except NP20 (p > 0.05), and increased GSH levels (p < 0.05) compared to MEM and HERP10. In conclusion, use of HERP (20 ηg/ml) on in vitro culture of isolated ovine preantral follicles can increase antrum formation, mitochondrial activity and GSH levels.     

Cervical transposition test using Hegar dilator at oestrus as a tool to select ewes for transcervical embryo collection

This study evaluated the cervical transposition method as a tool to select ewes for embryo collection by transcervical route. Adult Santa Inês ewes (n = 50) received Day 0 protocol for superovulation treatments. The cervix transposition test was performed both at oestrus and at the embryo collection time. The latter was preceded by hormonal cervical dilation. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 85.7%, 66.6%, 85.7%, 66.6% and 80.0%, respectively. The kappa index yielded a moderate score (κ = 0.52). In conclusion, the high sensitivity and accuracy indicate that the cervical transposition test is a screening option to select ewes for embryo collection by transcervical route.     

Effect of oxygen tension on in vitro viability and development of dog follicles enclosed within the ovarian cortex

Oxygen concentration has been shown to influence in vitro viability and growth of ovarian follicles. The present study examined the effect of oxygen tension on in vitro development of dog follicles enclosed within the ovarian cortex. Ovaries were obtained from domestic dogs (age, 8 months to 2 years), and cortical fragments were recovered. The cortices were then incubated on 1.5% (w/v) agarose gel blocks within a 4‐well culture plate containing Eagle Minimum Essential Medium (MEM). Ovarian follicles within the tissues were processed for histology and assessed for follicle density, viability and diameter immediately after collection (Control) or after 2 or 5 days of in vitro incubation. Apoptotic cells were assessed using TUNEL assay. Comparisons of follicular viability and diameter were performed using analysis of variance followed by Tukey's test (p < 0.05). Comparisons of follicle density and apoptosis among treatments were conducted using Non‐parametric Kruskal–Wallis test followed by Friedman's test (p < 0.05). No difference (p > 0.05) in follicle density was observed among groups at Day 2 of in vitro culture. However, the density of follicles within cortices cultured in 20% oxygen for 5 days significantly reduced compared to the Control and those incubated in 5% concentration. The viability of cultured follicles in all treatments decreased (p < 0.05) compared to the Control after 2 days incubation, and this value further reduced (p < 0.05) in 20% oxygen group at Day 5. There were no differences in the percentages of apoptotic follicles between the two treatment groups (p > 0.05). Nevertheless, after 5 days of culture, the percentage of TUNEL‐positive follicles increased significantly (p < 0.05) in cortices incubated in 20% oxygen environment. In conclusion, our findings demonstrated that 5% oxygen level was superior to 20% concentration in sustaining in vitro viability of dog follicles enclosed within the ovarian cortex.