Performance and behavior of pigs in finish phase subject to different programs of lighting

SUMMARY The aim of this study was to evaluate the use of lighting programs on performance, plasma concentration of melatonin and behavior of finishing pigs. The experiment was conducted in the pig farming sector UFLA, using 32 pigs in the finishing phase, for 48 days. The animals were housed in groups of two in each pen (experimental unit), distributed in a randomized block design, according to the initial weight. Four light periods were used (treatments): T1: natural light (LN); T2: 15 hours of light and dark by day nine (15L: 9E); T3: 19 hours light per day (19L: 5E); T4: 23 hours of light per day (23L: 1D). The variables analyzed were the performance (average daily feed consumption, average daily gain weight and feed conversion), the plasma concentrations of melatonin and the behavior (drinking, sniffing, leisure and eating). The change in photoperiod did not affect performance or melatonin concentration in pigs. The behavioral variables "digging", "eating", "drinking", did not differ in any of the periods studied, but leisure behavior was more occurring to the pigs receiving 15 hours of light. The increase in photoperiod showed no significant changes in performance or behavior of the animals.