Abstract
This report aimed to determine the effect of lipopolysaccharide (LPS) on food intake in broiler chicks with different rations. All birds received a starter diet until five days of age, but experimental diets were provided on days of injections. In experimental group one, chickens received an intracerebroventricular (ICV) injection of LPS (25, 50, and 100 ng) with a standard diet. In experimental group two, chickens received intraperitoneal (IP) injections of LPS (50, 100, and 200 µg) with a standard diet. In experimental group three, birds received ICV injections of saline and different diets. Accordingly, a standard diet without fat, a diet containing 20% higher nutrient energy than the standard, a diet containing 20% less nutrient energy than the standard, and a standard diet containing fat were offered to them to investigate the desire of chickens for the diets. Experimental groups four, five, and six were similar to experimental group three, except that the chickens received ICV injections of LPS. In experimental groups seven, eight, and nine, chickens received IP injections of LPS with different diets. Afterward, their cumulative food intake was measured until 180 min post-injection. According to the results, ICV and IP injections of LPS decreased food intake (P<0.05). However, the ICV injection of saline increased the desire of chickens for the standard diet with fat (P<0.05). The ICV injection of the LPS (50 and 100 ng) increased the appetite for a standard diet with nutrient energy 20% higher than the standard and a standard diet containing fat, at 120 and 180 min after the injection (P<0.05). In addition, IP injection of LPS (200 µg) significantly increased the desire for a standard diet with nutrient energy 20% higher than the standard and a standard diet containing fat (P<0.05). These results suggested the desire of chickens for different types of rations is affected by central or peripheral administration of the LPS.