Physiology, Endocrinology, and Reproduction

In total, 120 one-day-old female Ross 308 broilers were used to evaluate the effect of including oat hulls (OH), sugar beet pulp (SBP), and pea hulls (PH) at levels of 2.5, 5.0, and 7.5% in the diet on lipid metabolism of broilers from hatch to 21 d of age. The OH, SBP, and PH contained 0.7, 11.6, and 5.1% soluble fiber and 70.6, 47.4, and 49.6% insoluble fiber, respectively. The control diet contained 3,265 kcal of AMEn/kg, 22.1% CP, 1.3% digestible lysine, and 1.6% crude fiber (6.9% dietary fiber). The fiber sources were included in the experimental diets at the expense (wt/wt) of the control diet. Each treatment was replicated 6 times (a cage with 2 chicks). At 21 d of age, one chick per replicate was slaughtered and plasma lipid metabolites and liver lipid components were determined. At 21 d of age, the inclusion of fiber in the diet tended to reduce total cholesterol (P = 0.06) and to increase HDL cholesterol (P = 0.06) in plasma and reduced lipid components of the liver including total lipids, triglycerides, and total cholesterol (P < 0.05). Type of fiber did not affect total lipids, triglycerides, and LDL cholesterol in the plasma or the relative weight (% BW) of the liver. Plasma HDL, however, was higher in birds fed OH than in birds fed PH or the control diet with birds fed SBP being intermediate (P < 0.01). An increase in the level of fiber in the diet from 0 to 7.5% tended to decrease triglycerides in the liver from 7.37 to 6.00 mg/g across treatments (P = 0.08) but did not affect any of the other traits studied. It is concluded that the inclusion of fiber in the diet modified in different ways lipid metabolism in broilers at 21 d of age but that fiber sources differing widely in solubility and physico-chemical properties had little effect on these traits. An increase in the level of fiber reduced lipid components in the liver at this age.