The present work aimed to investigate the presence of T. vivax DNA in the semen of experimentally infected goats. Twelve male goats native to the Brazilian Northeast, adults, were randomly assigned to two experimental groups: the infected group consisting of six goats infected intravenously with 0.5 mL of blood containing approximately 1.25 × 10 trypomastigotes of T. vivax, and a control group composed of six uninfected goats. After the infection, clinical examinations aiming to evaluate rectal temperature, parasitemia and hematocrit were performed. Semen samples were collected from goats by electroejaculation on the 7th, 14th and 21st days post-infection (dpi). The recombinant DNA-encoding gene encoding the L-like-specific gene for T. vivax. The infection was characterized by increased rectal temperature, high parasitemia and significant reduction of hematocrit values. Results for T. vivax DNA detection using TviCatL-PCR were positive in all semen samples from the infected group collected on 7th, 14th and 21st dpi. The presence of T. vivax DNA in 7th dpi suggests the early invasion of the parasite in the reproductive organs. Also, the finding of T. vivax DNA in all periods analyzed may suggest the continued elimination of the parasite in the semen, which may increase the chances of sexual transmission. Thus, T. vivax DNA is recorded for the first time in the semen of infected goats. Thus, these data are of great importance, since the detection of the T. vivax genetic material in the semen may point to the possibility that the parasite may be transmitted through the sexual pathway.

Considering that neem (Azadirachta indica A. Juss.) causes deleterious effects on fertility, the objective was to evaluate the effect of feeding quail (Coturnix coturnix japonica Linnaeus, 1758) of 90 days old with neem seeds on seminal quality, biometric parameters, and testicular morphometrics, as an experimental model. After the 30 day adaptation period to the experimental conditions, birds were randomly distributed in five treatments of neem seeds incorporated into feed, with 10 replicates: T1 (0%), T2 (5%), T3 (10%), T4 (20%) and T5 (40%). After 60 days of receiving experimental rations, their semen was collected to evaluate the sperm quality, the birds were euthanized, and testes were submitted to biometric, histological, and histomorphometric evaluation. The data were evaluated by analysis of variance and later by Tukey test with a significance level of 5%. The mean values of testicle weight, length, and width significantly decreased in T4 and T5, due degeneration of germinal epithelial cells. In these treatments, it occurred a significant increase (P>0.05) in the average values of the tunica albuginea thickness and a significant reduction in the values of the seminiferous tubule diameter and the height of the germinal epithelium. In addition, the mean values of seminal volume, sperm concentration, sperm motility, vigor, and sperm viability were significantly reduced. Thus, the use of neem in bird feeding, as well as the use for therapeutic purposes, is questionable, considering its negative impact on reproduction.