Precalibration evaluation procedures for mid-infrared milk analyzers.

The purpose of this paper is to present a detailed account of the precalibration procedures developed and implemented by the USDA Federal Milk Market Administrators (FMMA) for evaluating mid-infrared (MIR) milk analyzers. Mid-infrared analyzers specifically designed for milk testing provide a rapid and cost-effective means for determining milk composition for payment and dairy herd improvement programs. These instruments determine the fat, protein, and lactose content of milk, and enable the calculation of total solids, solids-not-fat, and other solids.

Brain histidine and food intake in rats fed diets deficient in single amino acids.

Histidine (His) is elevated in plasma and brain during protein deficiency as well as in several pathological conditions, leading to the possibility of a direct effect on central nervous system (CNS) function. In this study, groups of weanling rats were fed diets containing graded levels of casein or a single indispensable amino acid (IAA: Leu, Val, Ile, Phe, Trp, Thr, Met or Lys) in order to produce nutritionally-deficient states. Body weight gains and food intakes were recorded daily for 2 wk.

Use of the peroxidase-antiperoxidase technique for differential staining of multiple cell types in the rat pancreatic islet.

Multiple staining of the endocrine cells of the pancreatic islet was studied in tissue obtained from adult rats. After fixation in Bouin's fluid and processing for light microscopy, the unlabeled peroxidase-antiperoxidase (PAP) technique was performed. Successful staining procedures used variations of the PAP technique with 3,3'-diaminobenzidine (DAB) and 4-chloro-1-naphthol (CN) as chromagens.

Control of physiological response in the rat by dietary nutrient concentration.

In three separate experiments, growing, male Sprague-Dawley rats were fed diets which contained: 1) graded levels of fiber 0-70%, 2) graded levels of pyridoxine 1-10 mg/kg diet, and 3) graded levels of casein 0-30%. The following physiological responses were measured in each respective experiment: 1) food intake, weight gain, serum triglycerides, 2) food intake, weight gain, SGPT levels, and 3) weight specific food intake, weight gain, relative testes weight. Diets were fed as a single source, and in each case, physiological response could be predicted as a function of dietary nutrient concentration.