ABSTRACT
Research data regarding exogenous melatonin effects on buck semen antioxidative status during the breeding and nonbreeding seasons are scarce or missing. The aim of this study was to investigate the effect of melatonin implants on the activity and ratios of antioxidative enzymes and on malondialdehyde concentrations in the seminal plasma and spermatozoa of French Alpine bucks during the 3 mo of the nonbreeding season. Two groups of randomly assigned bucks were either treated with melatonin (n = 6) or served as controls (n = 6). Semen samples were collected weekly, seminal plasma was separated from spermatozoa, and activities of glutathione peroxidase (GSH-Px), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), and the concentration of malondialdehyde were determined. The melatonin-treated bucks had significantly higher CAT/SOD and GSH-Px/SOD ratios, but a significantly lower GR/GSH-Px ratio in seminal plasma and spermatozoa during the different periods of the nonbreeding season. In conclusion, exogenous melatonin influenced the activities of all ratios and some single antioxidative enzymes tested in bucks' seminal plasma and spermatozoa. Here we provide the first evidence derived from an intervention, that is, melatonin treatment, which affects antioxidative enzymes ratios in the semen of bucks, and could thus be recommended as an indicator of oxidative stress severity and antioxidative status of semen.
Subject(s)
Goats , Melatonin/pharmacology , Seasons , Semen Analysis/veterinary , Semen/physiology , Spermatozoa/physiology , Animals , Antioxidants/metabolism , Antioxidants/pharmacology , Catalase/metabolism , Drug Implants , Gene Expression Regulation, Enzymologic/drug effects , Glutathione Peroxidase/genetics , Glutathione Peroxidase/metabolism , Glutathione Reductase/genetics , Glutathione Reductase/metabolism , Male , Melatonin/administration & dosage , Superoxide Dismutase/genetics , Superoxide Dismutase/metabolismABSTRACT
The aim of this study was to investigate the effects of exogenous melatonin on libido and semen quality parameters in bucks during the non-breeding season. Twelve bucks of the French alpine breed from 1.5 to 4 years of age were assigned into melatonin (MG) and control (CG) groups, with 6 bucks in each group. The experimental period was 3 months (March-May), divided into six periods of 15 days each. The bucks in the MG group received four melatonin implants at the end of March. Two semen samples were taken from the bucks by artificial vagina once per week and their libido estimated. Volume and spermatozoa concentration, their mass motility and motility, proportion of live and total abnormal and forms with abnormal head and tail were determined in the obtained ejaculate samples. The total number of spermatozoa and functional spermatozoa fraction in the ejaculate was also calculated. The MG bucks had significantly higher mass motility and motility of spermatozoa in the first half of April, and a higher proportion of live spermatozoa in the first and second half of April (p < .05). Differences in libido intensity were not significant. The results indicated that the application of melatonin significantly improved the qualitative parameters of semen in bucks, as seen in increased mass motility, motility of spermatozoa and proportion of live spermatozoa shortly following melatonin insertion. Therefore, the results of the current study are novel regarding the use of melatonin treatment during the non-breeding season to improve the qualitative parameters of ejaculates in bucks.
Subject(s)
Goats , Libido/drug effects , Melatonin/pharmacology , Semen/drug effects , Animals , Drug Implants , Male , Melatonin/administration & dosage , Seasons , Semen Analysis/veterinary , Sperm Motility/drug effects , Spermatozoa/drug effectsABSTRACT
This is a preliminary report on a multistate epidemiological model without age structure constructed on the grounds of the natural history of hepatitis B. In determining twelve essential epidemiological classes and related epidemiological parameters the lack of precise definitions of certain classes and their infectiousness was an important constraint in model formulation. For this reason the distribution of some classes and their parametric values were rather arbitrarily set. As more exact information on natural history becomes available it can be directly incorporated into the present model. The computer programme of the model has been written in basic language. The model was used for the simulation of endemic and epidemic situations. It was applied for simulating the natural course of infection as well as the effects of various public health interventions, such as passive and active immunization and/or application of appropriate sanitary and hygienic measures. The model is evaluated through the above simulations of actual and hypothetical situations. The cost-effectiveness analysis of various public health interventions can also be carried out with the model. The model in its present form, in spite of some uncertainties as far as epidemiological parameters are concerned, seems to be useful in the study of hepatitis B dynamics and its epidemiological patterns and in the search for effective and cost-effective control strategies. The model needs further refinement.
