Effects of dietary dihydropyridine supplementation on growth performance and lipid metabolism of broiler chickens

An experiment was conducted to investigate the effects of dihydropyridine supplementation on growth performance and lipid metabolism of broilers. A total of 480 one-day-old female Arbor Acres broiler chicks were randomly divided into four groups, each group had six replications of 20 birds. Each group was fed a maize-soybean meal diet supplemented with 0, 100, 200, 300 mg/kg dihydropyridine, respectively, for six weeks. At 42 days of age, body weight and feed intake were not affected by dihydropyridine, while feed efficiency was significantly increased by 8.4%, 15.0% and 12.0%, respectively (P < 0.05). The percentage of abdominal fat and the percentage of liver fat were reduced by 24.5%, 25.9%, 23.3%, and 23.6%, 26.7%, 26.0%, respectively (P < 0.05). The higher level of dietary dihydropyridine (200 or 300 mg/kg) increased the hormone-sensitive triglyceride lipase activity in liver and abdominal fat (P < 0.05). The lipoprotein lipase activity in abdominal fat was significantly decreased by dihydropyridine (P < 0.05). The activity of glucose-6-phosphate dehydrogenase and malic dehydrogenase in liver was significantly reduced, whereas the isocitrate dehydrogenase activity in liver was not affected by dietary dihydropyridine. The content of cAMP was significantly increased by dihydropyridine, but malondialdehyde content was decreased (P < 0.05). Dihydropyridine at doses of 100 and 200 mg/kg increased apolipoprotein B (P < 0.05), but 300 mg/kg dihydropyridine had no effect on apolipoprotein B compared with the control group. Triiodothyronine was significantly increased by dietary dihydropyridine (P < 0.05). There were no differences in apolipoprotein A, cholesterol, trigly-cerides, high density lipoprotein-cholesterol, very low density lipoprotein-cholesterol, thyroxine and insulin among dietary treatments. It is concluded that supplementing dihydropyridine has a beneficial effect on feed efficiency and lipid metabolism of broilers, and that 200 mg/kg dihydropyridine supplementation is the optimum dose.