Effects of Addition of Tissue‐Type Plasminogen Activator in In Vitro Fertilization Medium on Bovine Embryo Development and Quality

Plasminogen activators/Plasmin system plays pivotal role in regulating reproductive functions of mammals. Here, we examined the effects of modification of in vitro fertilization medium (IVF medium) with the addition of tissue‐type plasminogen activator (t‐PA), on bovine embryo development and quality, assessed by quantification of expression of various genes related to metabolism, oxidation, implantation and apoptosis. In addition, plasminogen activator activity (PAA) and plasminogen activator inhibition (PAI) were measured in the spent media. After conventional IVM, 2016 cumulus‐oocyte complexes (COCs) were divided into four groups with modified composition of the IVF medium containing t‐PA and/or its inhibitor epsilon‐aminocaproic acid (control, t‐PA, t‐PA+ε‐ACA, ε‐ACA). Presumptive zygotes were cultured for 8 days in synthetic oviductal fluid (SOF) medium; gene expression studies were carried out on morulae and blastocysts. t‐PA alone significantly suppressed cleavage and blastocyst formation rates, but this effect was neutralized by the addition of ε‐ACA. PAA in the treated group was significantly reduced by ε‐ACA, but without total elimination. Significant differences were detected in the expression of genes related to apoptosis and/or cell cycle arrest (BAX, BCL2L1, KAT2B) between embryos produced in t‐PA‐modified media and controls, giving an overall notion that the inferior developmental competence of treated embryos may be attributed to apoptotic phenomena induced by t‐PA. In conclusion, it appears that excessive t‐PA content in the IVF media, suppresses blastocyst formation rate, possibly due to induction of apoptotic phenomena.     

Amoebic meningoencephalitis caused by Balamuthia mandrillaris in an orang utan

Objective
To describe a case of meningoencephalitis caused by Balamuthia mandrillaris in an orang utan.
Design
A pathological case report.
Animal
A 20 years old male orang utan (Pongo pygmaeus).
Procedure
The disease process was investigated by clinical pathology, necropsy, histopathology and immunofluorescence labelling.
Results
The orang utan developed sudden onset of depression, lethargy, inappetence and apparent head pain. The condition was considered to be related to a 2 year history of upper and lower respiratory disease, and the animal was placed on antibiotics after extensive testing. By the seventh day the animal had become ataxic and disoriented and a brain abscess was suspected. He died on the ninth day of illness. At necropsy, and subsequent sectioning, the brain showed multiple circular, soft, white to grey brown areas of varying size, the largest being in the left temporal (3.5 cm diameter) and right occipital (2.5 cm diameter) regions of the cerebrum. Histological examination of these regions revealed many amoebic trophozoites and occasional cysts associated with areas of haemorrhage and inflammatory necrosis. The trophozoites were packed in perivascular spaces and their nuclei often contained two or more prominent nucleoli. Immunofluorescent labelling of histological sections suggested that the agent was B mandrillaris.
Clinical implications
This report provides further evidence that B mandrillaris , a free living amoeba, can act as a pathogen in animals as well as people, and cause fatal meningoencephalitis. Along with Naegleria and Acanthamoeba spp, B mandrillaris should be considered amongst the causes of acute onset meningoencephalitis in animals.     

Micromechanical "Trampoline" magnetometers for use in large pulsed magnetic fields

A silicon micromechanical magnetometer was constructed and successfully used in 60-tesla pulsed magnetic fields of less than 100-millisecond duration. The device is small, inexpensive to fabricate, and easy to use. It features a fast mechanical response (up to 50,000 hertz) and extremely high sensitivity yet is relatively robust against electrical and mechanical noise. Quantum oscillations in the magnetization of a 1-microgram sample of an organic superconductor, kappa-[bis(ethylenedithio)tetrathiafulvalene]2Cu(NCS)2, have been observed with this device.     

Management of land and livestock contaminated with polychlorinated biphenyls

Investigations were conducted on several small neighbouring beef cattle and sheep farms that were found to be contaminated with polychlorinated biphenyls (PCBs). The residues detected contained about 62% w/w chlorine and soil concentrations ranged from 0.35 to 1.9 mg/kg. Beef cattle and sheep grazing the contaminated land had PCB concentrations in their fat of 0.3 to 1.7 mg/kg and 0.19 to 0.45 mg/kg, respectively. The concentration of PCBs in the caudal fat of cattle was 0.3 to 2 times the concentration of PCBs in the land they were grazing and was positively related to stocking rates. PCBs were present in milk fat from cattle at about the same concentration as in caudal fat, and lactation appeared to contribute to decontamination. Wool grease from sheep contained about 1 to 2 times the concentration of PCBs in subcutaneous fat. Calves of contaminated cows also became contaminated. The half-life for decontamination of PCBs in a group of 8 young female beef cattle was calculated at 13 months. PCBs were detected in pasture samples at concentrations ranging from less than 0.01 mg/kg to 0.12 mg/kg. However, PCBs were not detected in any sample of hay cut from these paddocks. In 4 sheep fed a sole ration of this hay, traces of PCBs were detected in their fat following 89 days of feeding. Grazing livestock for meat production on land contaminated with PCBs is not recommended because livestock readily acquire residues, and PCBs persist in soil and livestock for long periods. Grazing sheep for wool production on land contaminated with PCBs may be an option.     

Serum Levels of Cardiac Markers NT‐proANP and NT‐proBNP in Brachycephalic bitches at Different Gestational Stages

The aim of this study was to determine serum levels of natriuretic peptide precursors (NT‐proANP and NT‐proBNP) during pregnancy in brachycephalic bitches. Fifteen healthy multiparous bitches were selected for this prospective study. Serum levels of NT‐proANP and NT‐proBNP were measured during anoestrous and at 14, 35, 42, 49 and 56 days (2nd, 5th, 6th, 7th and 8th weeks) of pregnancy. Fourteen animals had normal gestations, and one bitch developed single foetus syndrome. The natriuretic peptide levels of this animal were not included in this study; however, it is important to report that its NT‐proANP levels were four times greater than those of normal patients. There was no significant difference (p = 0.072) in NT‐proBNP levels between anoestrous (0.20 ± 0.10 ng/ml) and the different pregnancy weeks (0.27 ± 0.12 ng/ml). There was a positive correlation (p < 0.0001) between NT‐proANP and gestational age, and the levels of this marker increased significantly (p < 0.0001) during the 6th (0.26 ± 0.06 ng/ml), 7th (0.28 ± 0.04 ng/ml) and 8th weeks (0.29 ± 0.05 ng/ml) when compared to anoestrous (0.18 ± 0.02 ng/ml). NT‐proANP serum levels are correlated with gestational development and may be indicative of cardiovascular adaptation in canine brachycephalic pregnancy.     

Effect of cutting height and genetics on composition, intake, and digestibility of corn silage by beef heifers

This research was conducted to determine the effect of corn genetics and cutting height on the composition and nutritive characteristics of corn silage. An in situ study involving eight commercially available corn hybrids indicated main effects and interactions (P < 0.01) of hybrid and cutting height on NDF, ADF, and starch content and on in situ DM and NDF degradablility. Four ruminally cannulated Angus heifers (initial BW = 378 +/- 3 kg) were used in a 4 x 4 Latin square digestion experiment with a 2 x 2 factorial treatment arrangement. Main effects and interactions of hybrid (Pioneer Hi-Bred Int., Inc., hybrids 3335 and 3223) and cutting height (LO = 20.3 cm, and HI = 61 cm) were evaluated. Dietary treatment consisted of 40% chopped alfalfa hay and 60% corn silage. Although corn silage hybrids used were of equivalent maturity at harvest (60% milkline), 3335 treatments had 37.8% starch and 34.8% NDF, whereas 3223 treatments had 33.7% starch and 38.6% NDF. The LO treatments averaged 3.1 percentage units greater in NDF and 3.45 percentage units less in starch content than the HI treatments. Intake of DM was greater for heifers fed 3335-HI than 3335-LO; however, DMI was greater by heifers fed 3223-LO than 3223-HI (hybrid x cutting height interaction, P < 0.05). Starch intake was greater (P < 0.05) and NDF intake was less (P < 0.05) by heifers fed HI vs. LO and fed 3335 vs. 3223 dietary treatments. Digestibility of DM, starch, and NDF was greater (P < 0.05) by heifers fed 3223 than 3335 dietary treatments, but digestibility differences were not observed (P > 0.10) between cutting heights. Rate of in situ DM and starch degradability was not affected (P > 0.10) by hybrid or cutting height; however DM degradability was greater (P < 0.05) for HI than LO corn silage substrates at 8, 16, and 24 h of incubation. Rate of NDF degradability tended (P = 0.08) to be greater for 3223 than for 3335, and for LO compared with HI corn silage. Degradability of NDF was greater (P < 0.05) for 3223 compared with 3335 substrates at 24, 36, and 48 h of incubation. These data suggest fiber may not be an accurate measure of corn silage quality. Whereas cutting height affected chemical composition, we observed genetics to have a greater effect on corn silage quality.     

Age, FSH Dose and Follicular Aspiration Frequency Affect Oocyte Yield from Juvenile Donor Lambs

Experiments were conducted to determine the effects of lamb age, frequency of follicular aspirations, and hormone stimulation by fixed or variable FSH dose, on the number of collected oocytes and their maturational competence. In trial 1, the characteristics of follicular population (number and diameter of follicles) were studied in 40 lambs which were slaughtered at the age of 30 days (S1), 42 days (S2), 60 days (S3) and 5–6 months (S4), each n = 10. In trial 2, 27 lambs were divided into four groups. group MF lambs (n = 6) had follicular aspiration (OPU) in four monthly intervals commencing from the age of 8–9 weeks (sessions MF1, MF2, MF3 and MF4). In groups SF2, SF3 and SF4 (each n = 6), OPU was conducted once during the 12–13, 16–17 and 20–21 week of age, respectively. Ovarian stimulation was conducted with fixed FSH dose (3.52 mg/animal). In trial 3, 10 lambs (group MV) were treated as those of group MF apart from the FSH dose, which was administered according to the body weight in a dose of 0.27 mg/kg. The number and the size of follicles, the number and the quality of collected oocytes and the maturational competence of the oocytes were compared between and within groups. In trial 1, the total number and the number of small follicles were greater in groups S1 and S2 compared with those of S3 and S4 (p < 0.01). Similarly, the follicular population was greater in group MF1 than in group SF3 (p < 0.01). In sessions MF2, MF3, MV2, MV3 and MV4, more oocytes were collected in comparison with those from the respective once‐aspirated age mates (groups SF2, SF3 and SF4). In total, more (p = 0.02) oocytes per donor were collected from group MV (15.2 ± 5.5) than from group MF (9.0 ± 3.2). An absolute maturational failure was observed in oocytes collected from groups SF2 and SF3. Maturational competence varied between 16.7% and 58.3% (p = 0.017) among sessions of group MF, but it was more uniform among sessions of group MV (range 12.5–42.9%, p > 0.05). Our results indicate that firstly, the number and the quality of harvested oocytes from juvenile lambs can be much improved if follicular stimulation regime is adjusted to the body weight. Secondly, in terms of follicular population and oocyte quality, 3 and 4‐month‐old lambs are naturally bad oocyte donors, but this characteristic can be reversed by a previous follicular ablation.     

Effect of hybrid, maturity, and mechanical processing of corn silage on intake and digestibility by beef cattle

A study involving a 2 x 2 x 2 factorial arrangement of treatments was conducted to evaluate effects of hybrid (Pioneer 3335 and 3489), maturity (half milkline and blacklayer), and mechanical processing (field chopper with and without on-board rollers engaged) on intake and digestibility of corn silage. Forty Angus steers (322 +/- 5.2 kg BW) were assigned to the eight silage treatments (five steers per treatment) and individually fed using electronic gates. Diets consisted of 60% corn silage and 40% chopped alfalfa hay (DM basis). Following a 5-d adaptation period, intake was measured for 7 d and subsequently fecal samples were collected for 5 d. Chromic oxide (5 g/d) was fed beginning 7 d before fecal sample collection and digestibility was determined by the ratio of Cr in the feed and feces. Steers were reallocated to treatments and these procedures were repeated, providing 10 observations per treatment. In addition, all silages were ruminally incubated in six mature cows for 0, 8, 16, 24, 48, and 96 h to determine extent and rate of DM, starch, NDF, and ADF disappearance. Processing increased DMI of hybrid 3489 but did not affect DMI of hybrid 3335 (hybrid x processing; P < 0.06). Total tract digestibility of DM, starch, NDF, and ADF decreased (P < 0.01) as plant maturity increased. Maturity tended to decrease starch digestibility more for hybrid 3489 than for hybrid 3335 (hybrid x maturity; P < 0.10). Processing increased (P < 0.01) starch digestibility but decreased (P < 0.01) NDF and ADF digestibility, resulting in no processing effect on DM digestibility. There was a numerical trend for processing to increase starch digestibility more for latethan for early-maturity corn silage (maturity x processing; P = 0.11). Processing increased in situ rates of DM and starch disappearance and maturity decreased in situ disappearance rates of starch and fiber. These data indicate that hybrid, maturity, and processing all affect corn silage digestibility. Mechanical processing of corn silage increased starch digestibility, which may have been associated with the observed decreased fiber digestibility.