In vitro adverse effects of amitraz on semen quality: Consequences in bovine embryo development.

Veterinary drugs are potential environmental pollutants that interfere with male reproductive function. Infertility has increased, and it is known that environmental toxins contribute to declining sperm parameters. Amitraz {N,N-[(methylamino) dimeth-ylidyne] di-2,4-xylidine} (AMZ) is a formamidine pesticide widely used as an insecticide and an acaricide. The aim of this study was to evaluate the toxicity of AMZ in bovine sperm. Three experiments using frozen-thawed bovine semen incubated with AMZ for 2 h were carried out. Negative and solvent (dimethyl sulfoxide) controls were run simultaneously with treatments. In experiment 1, the AMZ concentrations used were 10, 15 and 25 µg AMZ/ml and the sperm parameters evaluated were viability, mitochondrial activity, acrosomal status, functional membrane integrity and apoptosis. In experiments 2 and 3, 25 µg AMZ/ml was used to evaluate fertilizing capacity, embryo development and blastocyst DNA damage. In experiment 1, 25 µg AMZ/ml decreased sperm viability (P = 0.01), reduced mitochondrial activity (P = 0.03) and induced apoptosis (P < 0.01). Also, 15 and 25 µg AMZ/ml affected functional membrane integrity (P < 0.01). In experiment 2, AMZ did not alter sperm-zona binding (P = 0.40) and pronucleus formation (P = 0.36). In experiment 3, 25 µg AMZ/ml decreased the rate of embryo development (P < 0.01) and increased apoptosis (P = 0.03). These results suggest that AMZ induced alterations in bovine sperm, probably affecting male fertility at concentrations that could be present in the environment.

Effects of Parenteral Supplementation with Minerals and Vitamins on Oxidative Stress and Humoral Immune Response of Weaning Calves.

We aimed to evaluate the effects of injectable mineral and vitamin supplementation on weaning calves subjected to a low-stress (fence-line) weaning system. Seven-month-old Aberdeen Angus female calves (n = 40, 152 ± 11 kg body weight) from a selenium-deficient area of extensive cattle production on natural grass were randomly assigned to two groups (n = 20 each). One group received subcutaneous supplementation with copper, zinc, selenium, manganese and vitamins A and E (SG), and the other was given sterile saline solution (CG). The animals were supplemented twice, seven days before weaning (day -7) and on the day of weaning (day 0), and they were evaluated 30 (+30) and 60 (+60) days after weaning. Total antioxidant status (TAS), selenium-dependent glutathione peroxidase (GPx) activity, body weight, and average daily gain (ADG) were evaluated. Additionally, antibody titers were assessed prior to and after each immunization with a vaccine containing bovine herpes virus type 1 (BoHV-1). On day +30, body weight (p = 0.03) was higher in SG, whereas TAS (p = 0.02) and GPx (p = 0.0038) activity were lower in CG and remained constant in SG. Antibody titers increased in SG and CG following immunization, being higher in SG on days +30 and +60 (p < 0.05). In conclusion, parenteral supplementation of minerals and vitamins with antioxidant effects in a low-stress weaning system prevented the decrease in TAS and GPx activity, improved antibody response and had positive effects on body weight.

Assessment of Cu-Zn EDTA Parenteral Toxicity in Calves.

Copper (Cu) parenteral administration is used in a beef cow-calf operations to prevent or correct Cu deficiency in bovines. At present, Zinc (Zn) salts have been incorporated to complement Cu antioxidant effect. A risk of hepatotoxicity generated by overdose is a negative consequence of injectable Cu application. Cu-Zn EDTA appears as an alternative; however, data about its toxicity is unknown. The aim of this study was to assess toxicity risk of different doses of Cu-Zn EDTA in calves. Thirty two Aberdeen Angus calves of 162 (±20) kg BW were assigned to 4 groups (n = 8), homogeneous in weight, sex, and age. Cu-Zn EDTA was administrated in doses of 0.3 mg/kg BW (group 1X); 0.6 mg/kg BW (group 2X); 0.9 mg/kg BW (group 3X) and sterile saline solution (control group-with no treatment). Clinical and blood parameters in animals were monitored during 28 days. In groups' control, 1X and 2X there were no alterations in the assessed parameters. In group 3X, one of the animals showed depression, permanent decubitus, and muscular twitching; that animal had to be killed in extremis for humanitarian reasons. Necropsy and Cu tissue concentration findings confirmed intoxication in the clinically affected animal. The rest of the animals in group 3X showed only a temporary increase in liver enzymes. The results indicate that a dose of 0.9 mg/kg BW of Cu as Cu-Zn EDTA is potentially hepatotoxic, this dose is similar to other soluble salts of parenteral administration.

The prevalence of chromosomal aberrations in Argentine air crew members.

The authors analyzed the effects of chronic exposure of Argentine air crew members to low doses of ionizing radiations. Genetic damage induced by either low doses or low rates of ionizing radiation was higher than expected. Seventy-one heparinized blood samples were obtained from technical ground workers (group A; n = 10), pilots of domestic flights (group B; n = 14), pilots of transequatorial flights (group C; n = 17;), pilots of transpolar flights (group D; n = 17) and retired pilots (group E; n = 10) The frequency of dicentric chromosomes was higher in groups B and C compared with groups D and E. These observations suggest that the exposure of the aircraft to ionizing radiations may induce chromosomal aberrations. However, dicentric chromosomes in both domestic and retired pilots are still high compared with dicentric control participants.