Protein quality of various raw and rendered by-product meals commonly incorporated into companion animal diets.

Several experiments were conducted to evaluate the protein quality of various raw and rendered animal by-product meals commonly used in companion animal diets. Six freeze-dried raw animal meals (beef lungs, pork lungs, sheep lungs, pork livers, oceanfish, chicken necks) and 3 rendered animal meals (lamb meal, regular ash poultry by-product meal, and low ash poultry by-product meal) were fed in chick assays to determine Lys and TSAA bioavailability, protein efficiency ratio (PER), and net protein ratio (NPR). Each experimental diet was offered to 4 replicates of 5 chicks per pen in all growth assays. Furthermore, each animal by-product meal was fed to mature White Leghorn roosters for determination of true AA digestibility. All freeze-dried, raw animal meals were offered to 5 replicate roosters, and all rendered animal meals were offered to 4 replicate roosters. Most raw animal meals exhibited moderate to high protein quality. Lysine bio-availabilities ranged from 86 to 107% and 70 to 99% for raw and rendered animal meals, respectively. Bio-availability of TSAA ranged from 64 to 99% and 61 to 78% for raw and rendered animal meals, respectively. The PER values ranged from 2.83 to 4.03 and 2.01 to 3.34 for raw and rendered animal meals, respectively. The NPR values ranged from 3.83 to 4.8 and 3.05 to 4.12 for raw and rendered animal meals, respectively. Despite a numeric increase in NPR vs. PER values, the overall ranking of animal meals remained similar. Lamb meal had the poorest PER and NPR values, and pork lungs had the greatest values. Total essential AA digestibility and total AA digestibility ranged from 93.6 to 96.7 and 90.3 to 95.5%, respectively, for raw animal meals and 84.0 to 87.7 and 79.2 to 84.8%, respectively, for rendered animal meals. Rendered animal meals generally had lower protein quality than raw animal meals, with lamb meal consistently having the poorest protein quality and pork livers having the greatest protein quality.

A calibration system for X-ray generators and tube factors.

An apparatus (Machlett's Dynalyzer II system) is described that makes real-time dynamic tests on the output and performance of the X-ray tube and generator so that a single exposure gives information on mA and mAs; exposure time (ms); kVp anode to earth; kVp cathode to earth; kVp cathode to anode; tube filament current; line voltage and radiation output of the tube (mR). The method of use is described together with the results of comparisons made with other test equipment. Some novel design features are of particular interest. The results show that by using this apparatus present design characteristics of X-ray generator-control-tube systems are such that the accuracy of calibration can be improved by at least an order of magnitude.