DEVELOPMENT AND TESTICULAR HISTOLOGY OF LIGHT ROOSTERS SUBMITTED TO DIFFERENT PHOTOPERIODS

Abstract

With the objective of evaluating the effects of different photoperiods on the development and testicular histology of light roosters, an experiment was conducted in the Animal Science Department of the Federal University of Lavras. 48 roosters of the Lohman LSL strain, aged 133 days were utilized, they themselves being submitted to 3 treatments: 1) Continuous photoperiod, 2) Intermittent photoperiod and 3) Growing natural photoperiod. The animals were allotted to a completely randomized experimental design, with 4 replicates being the experimental unit being made up of 1 animal. The experimental period lasted 140 days and the variables evaluated were: body weight, weights of the right (PTD) and left testes (PTE), in grams; diameter of the seminiferous tubules (DTS) and thickness of the seminiferous epithelium (EES), in micrometers and number of cells of the seminiferous tubules (Sertoli cells, rounded spermatogonia and spermatids). The differences between treatments were compared by the Scott Knott test (5%). A significant effect was not observed (P>0.05) of the photoperiods and the ages on the analyzed variable, with exception of the number of spermatogonia that had presented quadratic variation with the increase of the age of the animals. It follows that photoperiods continuous, intermittent or growing natural light can be utilized for creation of light roosters over the reproductive period without harming the testicular parameters. Had to the lesser expense of energy that can be gotten with the use of Growing natural photoperiod, this would be the recommended program more for the males, with regard to the testicular characteristics.