Desempenho e características do sêmen de galos leves submetidos a diferentes fotoperíodos

Abstract

With the aim of evaluating the effects of different photoperiods on the performance and semen characteristics in roosters of light strains, an experiment was carried out at Animal Science Department of the Universidade Federal de Lavras. A total of 24 roosters of the Lohman LSL strain (light), aged 19 weeks was used, they themselves being submitted to 3 treatments: 1) continuous photoperiod; 2) intermittent photoperiod and 3) growing natural photoperiod. The birds were housed in a shelter divided into 3 environments, so that the lighting of one did not interfere upon the other. The experimental design was completely randomized, with 8 replicates. The experimental unit being made up of 1 rooster. The experimental period lasted 20 weeks and the variables evaluated were: feed intake (g/bird/day), body weight (g), seminal volume (ml), spermatic motility (%) and vigor (0 to 5), spermatic concentration (number of cells x 109), number of total spermatic cells (NCT- volume x concentration) and spermatic morphology (alterations of head, tail and total alterations). The roosters submitted to continuous light showed increased feed intake (P<0,05), but didn't influence (P>0.05) of the photoperiods on the other variables. One concluded that the continuous photoperiods, intermittent or growing natural light may be utilized in open shelters for light roosters over the reproductive period without harming the semen characteristics.