Rheas (Rhea americana) belongs to the ratite group. Considering the commercial significance of this birds, some techniques, such as semen collection, were standardized. In this study, 107 male rheas (3 to 4 years of age) reared in commercial farms in the state of São Paulo, Brazil, were used. Semen was collected during the breeding and offbreeding seasons of 2001, 2002, and 2003. Bird hierarchical behavior was observed. Birds were restrained performed using a box and a black hood. Semen was collected by digital pressure on the base of the phallus, which size was measured, and the presence or absence of spiral shape was observed. Immediately after collection, semen samples were evaluated for volume, motility, sperm concentration, and morphology. In a limited number of birds, blood samples were collected to measure testosterone levels. Among the 69 birds studied during the breeding season, 44 presented large phalluses, out of which 26 showed spiral shape. The method of semen collection was efficient. The following semen parameter results were obtained: volume (0.68 ±0.14 ml), motility (61.11±11.54%), sperm concentration (3.29±1.33 x10 9 sptz/ml), and number of spermatozoa per ejaculate (2.40±1.38x10 9 sptz/ml). Morphological abnormalities were analyzed and recorded. Testosterone levels were statistically different (p = 0.0161) between the breeding and non-breeding season (53.28±18.41 ng/ml and 5:57±3.81 ng/ml, respectively). Variations in phallus size were also found between the breeding and non-breeding seasons. Larger phalluses and higher testosterone levels were correlated with dominant behavior. The results of the present experiment confirmed that it is possible to collect semen from rheas, allowing the future use of biotechnologies such as artificial insemination.

This study aimed to detect the most deleterious ROS for goat sperm and then supplemented the extender with a proper antioxidant. For this, 12 adult goats (aged 1-7) were used. Fresh samples were submitted to challenge with different ROS (superoxide anion, hydrogen peroxide, and hydroxyl radical) and malondialdehyde (MDA-toxic product of lipid peroxidation). After experiment 1, sperms were cryopreserved in extenders supplemented to glutathione peroxidase (Control: 0 UI/mL; GPx1: 1 UI/mL; GPx5: 5 UI/mL, and GPx10: 10 UI/mL) and catalase (Control: 0 UI/mL; CAT60: 60 UI/mL; CAT120: 120 UI/mL, and CAT240: 240 UI/mL). Each sample was evaluated by motility, plasma membrane integrity (eosin/nigrosin), acrosome integrity (fast green/rose bengal), sperm morphology, assay of the sperm chromatin structure, mitochondrial activity (3,3-diaminobenzidine), and measurement of lipid peroxidation (thiobarbituric acid reactive substances [TBARS]). It was possible to observe a mitochondrial dysfunction (DAB-Class IV) and low membrane integrity after hydrogen peroxide action. However, the high rates of TBARS were observed on hydroxyl radical. CAT240 presents the lower percentage of plasma membrane integrity. It was possible to attest that hydrogen peroxide and hydroxyl radical are the more harmful for goat sperm. Antioxidant therapy must be improving perhaps using combination between antioxidants.

No abstract

One reason for lower fertility of European bulls in tropical regions is a higher rate of oxidative stress caused by increased production of reactive oxygen species (ROS) not compensated by antioxidant protection. In that regard, sperm are extremely susceptible to oxidative stress due to a high concentration of polyunsaturated fatty acids (PUFA) in their plasma membranes. However, the presence of these PUFA is fundamental for sperm to be fertile and resistant to cold shock. Thus, treatments that suppress oxidation may increase productivity of these animals. This study aimed to evaluate the most damaging ROS for European bulls subjected to heat stress and to determine a possible antioxidant-targeted treatment. In a second step, we sought to verify the efficiency of the interaction between a diet rich in PUFA and a targeted antioxidant treatment on the quality of ejaculated and epididymal sperm in European bulls subjected to testicular heat stress. Four Bos taurus bulls were subjected to scrotal insulation for 5 days, with semen collection (electroejaculation) 60 days after insulation. Semen from each bull was divided into 4 aliquots and subjected to 4 ROS-generating systems: superoxide anion (xanthine/xanthine oxidase), hydrogen peroxide, hydroxyl radical (ascorbate + ferrous sulfate), and malondialdehyde (MDA; lipid peroxidation product). Samples were incubated for 1 h and assessed by computerized sperm analysis (CASA); eosin/nigrosin (membrane integrity); fast-green/Bengal rose (acrosome integrity); 3,3′ diaminobenzidine (mitochondrial activity); sperm chromatin structure assay (DNA fragmentation); and thiobarbituric acid reactive substances (lipid peroxidation). Overall, MDA had the most deleterious effects on semen quality of Bos taurus bulls subjected to acute heat stress. Thereafter, 16 bulls were subjected to testicular insulation and allocated into 4 groups: control (n = 4; given mineral oil; placebo); vitamin E (n = 4, given 5 mL of Monovin® every 13 days); PUFA (n = 4; given 4 kg day–1 Megalac®); and PUFA+vitamin E (n = 4; combination of PUFA and vitamin E treatment groups). Semen was collected on the day of installation of the insulation, on the day it was removed, and 30 and 60 days later. Overall, vitamin E reduced heat stress-induced damage to sperm DNA and mitochondria, but only in samples collected from the epididymis. Similarly, the combination of vitamin E and PUFA supplementation improved sperm motility patterns. Therefore, a combined antioxidant treatment (vitamin E and PUFA) may reduce damage to sperm caused by acute heat stress in European bulls. However, this treatment may be more effective if instituted before heat stress.