Effects of Exogenous Glutathione on the Quality of Chilled Bull Semen

Glutathione (GSH) at concentrations of 0.0 (control), 0.5, 1.0, 2.0 and 3.0 mM was added to chilled bull semen to determine its effects on the keeping quality of semen used for artificial insemination (AI). The semen was preserved with egg yolk citrate extender. All samples were stored at 4-8 degrees C for 5 days. Sperm motility and proportion of abnormal acrosome were assessed daily. Sperm motility was significantly (p < 0.01) higher in the semen treated with 0.5 mM glutathione than in untreated semen on each day. The optimum sperm motility (>or=50%) for AI was retained significantly (p < 0.01) for 3 days in 0.0, 0.5, 1.0 and 2.0 mM glutathione treated semen, whereas in 0.3 mM glutathione-treated semen, sperm motility was 46.8% for 3 days. Acrosomal damage was significantly (p < 0.01) reduced after addition of 0.5 mM GSH in the preserved semen. Bull semen can be preserved in chilled condition for 5 days with 0.5 mM GSH with sperm motility above 40% and 12% acrosome abnormality.     

Indications and implications for testing of milk urea in dairy cattle: a quantitative review. Part 1. Dietary protein sources and metabolism

MILK UREA CONCENTRATIONS IN DAIRY CATTLE: There has been increased use of milk urea concentration as an indicator of dietary protein intake and protein metabolism in dairy cattle over recent years. The value of milk urea content data in predicting dietary composition, particularly for pasture-fed cattle, has not been well described. PROTEIN METABOLISM AND UREA SYNTHESIS: Many factors influence the degradation of dietary proteins in the rumen, post-ruminal protein metabolism and urea synthesis in cattle. Strong positive correlations between nitrogenous fertiliser use and the crude protein content of pastures were identified by use of meta-analysis. Similar strong positive correlations were noted between dietary protein intake, rumen ammonia and plasma urea concentrations. The costs of urea synthesis include energy losses, and importantly, the loss of endogenous amino acids, which are deaminated in the synthesis of urea. MILK UREA AS AN INDICATOR OF PROTEIN METABOLISM: Urea concentrations in blood, plasma and milk are strongly correlated. Milk is an adequate indicator of blood and plasma urea content, but non-nutritional factors may significantly influence milk urea concentrations. Recommendations for dietary protein management based on milk urea concentrations must be undertaken with care.     

Pathology and Neurotoxicity in Dogs after Repeat Dose Exposure to a Serotonin 5-HT1B Inhibitor

AZD3783, a cationic amphiphilic drug and a potent inhibitor of the 5-hydroxytryptamine (5-HT_1B) receptor, was explored as a potential treatment for depression. To support clinical trials, repeat dose toxicity studies in rats and dogs were conducted. Here we report toxicity findings in dogs after dosing from 1 to 3 months. In the 1-month study, there were minimal neuronal vacuolation in the brain, a marked increase in liver enzymes accompanied by hepatocellular degeneration/necrosis and phospholipidosis (PLD), and PLD/cholecystitis in the gallbladder of animals dosed at 47 mg/kg/day. In the 3-month study, neurotoxicity resulted in euthanasia of one animal dosed at 30 mg/kg/day after 86 days. Extensive pathologic changes were seen in all animals in retina epithelium (inclusion bodies), brain (neuronal vacuolation, degeneration, or necrosis and nerve fiber degeneration), spinal ganglia (vacuolation, degeneration, or necrosis), as well as sciatic and optic nerves (degeneration). Pigment-laden macrophages were observed in the lung, kidney, liver, gallbladder, bone marrow, gastrointestinal tract, and lymphoid tissues. Also seen were vitrel and retinal hemorrhage in the eyes. A brain concentration and pathology study showed that the concentration of AZD3783 in the brain was approximately 4 times higher than in the plasma after 4 weeks of dosing, however, they were similar in all regions examined, and did not correlate with areas with pathologic findings. Our findings with AZD3783 in dogs have not been reported previously with other CNS compounds that effect through serotonergic pharmacology.     

MALDI‐MS Lipid Profiles of Oocytes Recovered by Ovum Pickup from Bos indicus and 1/2 indicus × taurus with High vs Low Oocyte Yields

The aim of the present study was to compare the lipid profile in oocytes of indicus and 1/2 indicus × taurus cows with high and low antral follicle count (AFC)/oocyte yields. After an OPU procedure (D0), antral follicles ≥3 mm were counted by ultrasonography (D4, 19, 34, 49, 64), and cows were assigned to groups with either high AFC (≥30 follicles; indicus, NH group; 1/2 indicus × taurus, AH group) or low AFC (≤15 antral follicles; indicus, NL group; 1/2 indicus × taurus, AL group). The lipid profiles of the oocytes were determined by MALDI‐MS. For GI, GII and GIII oocytes, the indicus samples tend to cluster separately from the 1/2 indicus × taurus samples. The lipid species [PC (P‐38:5) + H]⁺ and/or [PC (P‐36:2) + Na]⁺, [PC (38:2) + H]⁺, [PC (38:5) + Na]⁺ and [TAG (60:8) + NH⁴]⁺ were more abundant in indicus (NH and NL groups) than 1/2 indicus × taurus. The higher lipid content in the indicus oocytes likely reflects differences in the rate of lipid metabolism and may contribute to oocyte competence and embryo development.     

Exogenous paraoxonase‐1 during oocyte maturation improves bovine embryo development in vitro

Paraoxonase‐1 (PON1) is an enzyme found in serum and follicular fluid that protects cell membrane and circulating lipids against oxidative damage. The aims of this study were to measure the direct effects of recombinant PON1 (rPON1) on bovine oocyte maturation at the molecular level (gene expression) and to measure the carry‐over effects of PON1 on pre‐implantation embryo development in vitro. COCs were submitted to IVM with the addition of 0.0, 0.02, 0.04 and 0.08 mg ml^?1 of rPON1, corresponding to an average PON1 arylesterase enzyme activity of 2.2 ± 0.4, 15.5 ± 1.5, 30.2 ± 3.0 and 57.9 ± 5.0 U ml^?1, respectively. The results indicated that addition of rPON1 during IVM improved embryo development in a dose‐dependent manner as D7 embryo development was 22.2%, 29.4%, 32.2% and 37.0% for the treatment groups, respectively (p = 0.02). In conclusion, addition of PON1 enzyme during IVM exerted dose‐related positive effects on embryo development rates to blastocysts.     

Lipid profiles of canine spermatozoa as revealed via matrix‐assisted laser desorption/ionization mass spectrometry

In this study, we investigated the ability of matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) to characterize the lipid contents of canine spermatozoa. For that, samples of pure semen were analysed. Indeed, quite comprehensive lipid coverage was observed, and the most abundant phospholipid ions detected were from four phosphatidylcholines, that is those of m/z 760.6; 782.6; 808.6; and 830.6 and one of m/z 725.6 from a sphingomyelin. In conclusion, MALDI‐MS was found to offer an easy, fast, accurate, and sensitive analytical method for lipid profiling in canine spermatozoa and could be used as a tool to select sires by assessing the relationship between sperm lipid profiles and variables such as age and breeding history as well as to study the effects of cryopreservation on lipid contents.     

Effect of oestrous synchrony between embryo donors and recipients,embryo quality and state on the pregnancy rate in beef cattle

This study aimed to evaluate the effect of oestrous synchrony between donors and recipients and the embryo quality on the pregnancy rate in beef cow recipients. The experiment was performed over two years at an embryo transfer (ET ) centre in Southern Brazil. Ninety Aberdeen Angus cows were subjected to superovulation (SOV ) protocols, resulting in the recovery of 1,048 transferable embryos. Eleven groups were formed with intervals of 6 hr, from ?30 to +30 hr, with respect to recipient versus donor oestrous detection. Evaluation of embryo quality was according to the IETS guidelines. The overall pregnancy rate was 52%. Effects related to donor and recipient oestrous synchronization on pregnancy rate were observed (p  =  .01), ranging from 36% to 50%. The embryo quality rate affected the pregnancy rate, where Grade I resulted in 57% and Grade III in 43% of pregnancy (p  <  .001). The embryonic state (frozen or fresh) showed no (p  >  .05) effect on pregnancy rate: 53% for fresh embryos and 44% for frozen embryos. The odds ratio for explanatory variables causing pregnancy indicated that Grade III embryos had 31% less chance of conception compared to Grade I. Thus, oestrous synchrony between donor and recipient, considering ±30 hr apart, can affect the pregnancy rate along with embryo quality.