No abstract

The effects of dietary supplementation with acetic or propionic acid, given at a level of 3% of diets containing 2,500 or 2,750 kcal of metabolizable energy per kg, on levels of blood glucose, and on lipid, protein, and energy metabolisms were studied in female broiler chicks. Voluntary feed and energy intakes, as well as body weight gain, decreased significantly with the inclusion of the acids in either diet, in decreasing order of effect: propionate > acetate > nonsupplemented controls. The relative weight of the abdominal adipose tissue decreased significantly with the inclusion of either acid, but was unaffected by dietary energy level. In contrast, the weight of the liver was higher in birds fed the low-energy diet, but was unaffected by the anorectic agents. Inclusion of the acids increased the concentration of volatile fatty acids in the cecum and blood plasma. The rate of clearance of plasma propionate was greater than that of acetate. Anorectic agents and dietary energy density exhibited a synergistic effect on feed intake. These agents altered blood metabolites involved in lipid and energy metabolisms, but not in that of protein. Plasma metabolites and enzymes, particularly β-hydroxybutyrate and alkaline phosphatase, reflected the degree of feed restriction, supporting the hypothesis that the hypophagic effect of these acids is due to metabolic intervention.

Summary ― The developmental pattern of apolipoprotein in the plasma with regard to lipid concentration was characterized during the transition of pullet females to the laying phase in commercial laying hens (Gallus domesticus). Apo-I I was isolated from the plasma of estrogen-administered roosters, and a rapid ELISA was developed for its quantification in chickens. The sensitivity of the assay was 5 ng/ml, and the inter-and intra-assay coefficients of variation were 4 and 8%, respectively. Whereas no detectable levels of apo-11 could be monitored in the blood plasma of immature chickens, the level increased slightly to 23 weeks of age and sharply at the onset of lay. This profile reflects the dramatic changes in lipid metabolism at the onset of lay, and concurs with the concentration of total lipids in the plasma and with egg production rate. Plasma apo-II of 2 laying strains differing in body weights but compared at approximately similar egg production rates, tended to be slightly higher in heavy vs light-weight type hens. Oogenesis was speculated to be the main factor affecting both apo-II and total lipid profiles in chicken plasma, enabling efficient delivery of VLDL to the egg. apolipoprotein VLDL-11 / chicken / hen / egg production rate / lipid