K Leske | PubMed Health

PubMed2002

The development of feedstuff retainable phosphorus values for broilers.

Presently, phosphorus requirements are based on consumption of nonphytate phosphorus (NPP), which does not account for the fact that NPP may not be completely available and that phytate phosphorus can be partially utilized to fulfill phosphorus requirements. Phosphorus retention values for feed ingredients, accounting for NPP and phytate phosphorus, and total retainable phosphorus requirements are needed to formulate diets that meet the phosphorus requirements of poultry but that do not result in excessive amounts of phosphorus in poultry excreta. A bioassay was conducted to determine retention of phosphorus from calcium phosphates. Eight levels of a reagent-grade monocalcium phosphate, monohydrate, (MCP) were added to a cornsoy, semi-synthetic basal diet containing an acid-insoluble ash marker and offered to individually caged 10-d-old male broilers. After acclimation to the diets for 3 d, excreta were collected for 48 h. Diet and excreta samples were analyzed for total phosphorus, phytate phosphorus, and acid insoluble ash. Retentions of the basal total, NPP, and phytate phosphorus were determined to be 43.2, 65.5, and 32.3%, respectively. Retention of the phosphorus from different phosphorus sources was determined to be dependent on the amount of source included in the diet. The maximum retentions of total phosphorus, NPP, and phosphorus from MCP for the basal-MCP test diets were 67.6, 80.2, and 98%, respectively. The maximum retention of dietary retainable phosphorus occurred with a 2:1 ratio of 0.48% calcium and 0.24% retainable phosphorus. The retainable phosphorus intakes for 10-to-15-d-old broilers required to provide a steady physiological state was 108 mg/d, as determined by two-line regression analysis. Retainable phosphorus requirements based on segmented line regression analysis using bone strength measurements for 0-to-3-wk-old chicks and 3-to-6-wk-old broilers were 0.39 and 0.30%, respectively.

Animal Feed↗

PubMed1990

Two distinct yolk lipoprotein complexes from Caenorhabditis elegans.

The four yolk polypeptides of the nematode Caenorhabditis elegans are found in two types of lipoprotein particle: 12 S particles with Mr estimated at 450,000 and 8 S particles with Mr estimated at 250,000. Both types of particle contain approximately 8% phospholipids, 3% triglycerides, and 3% other lipids by mass. All four C. elegans yolk polypeptides can be found in either 12 or 8 S particles, depending upon the conditions of isolation. While the properties of the 12 and 8 S lipoprotein particles are consistent with a dimermonomer relationship, the asymmetric distribution of the yolk polypeptides between 12 and 8 S fractions suggests that at least two different oligomeric lipoprotein complexes are present in C. elegans embryos. In order to clarify the subunit composition of the C. elegans yolk lipoproteins, the patterns of polypeptides retained in immunoaffinity binding procedures by immunoglobulins of different antigenic specificities have been compared. When immunoaffinity binding is performed in the absence of sodium dodecyl sulfate, three C. elegans yolk proteins (yp170A, yp115, and yp88) are retained together by polyclonal immunoglobulins directed against either yp115 or yp88. A monoclonal immunoglobulin also retains these three proteins together. In contrast, a second monoclonal immunoglobulin retains only the fourth yolk protein (yp170B). Aggregate species, evidently reflecting the spontaneous formation of interchain disulfide bonds, indicate that yp170A and yp88 are physically associated, whereas yp170B self-associates in dimers. It is concluded that there are two distinct lipoprotein complexes in C. elegans: the A complex, which consists of yp170A, yp115, and yp88 and is essentially heterodimeric and the B dimer, a simple dimer of yp170B.

Animals↗