title: Nitrogen metabolism, tissue carnosine concentration and blood chemistry of gravid swine fed graded levels of histidine.
abstract: Three nitrogen metabolism experiments were conducted to determine the qualitative and quantitative histidine need of first-litter gilts during the last third of pregnancy. A completely purified, crystalline 8amino acid diet was formulated to meet all nutrient needs of the gravid gilt when 2 kg/day was fed. Experiments 1 and 2 were 9-day nitrogen balance studies, each consisting of three littermate gilts subjected to three levels of dietary L-histidine in a Latin square arrangement of treatments. Nitrogen retention was depresed, but not significantly, when less than 0.12% histidine was fed. Complete deletion of histidine, however, did not depress retention below that observed when 0.06% was fed. This suggested that either histidine biosynthesis or its release from endogenous reserves was confounding retention data. Therefore in a third experiment, two gilts were fed a histidine-free diet for 24 days in an attempt to deplete endogenous reserves. For comparison, two siblings were fed 0.12% histidine during this same period. Nitrogen retention tended to be lower for gilts fed the histidine-free diet during each of three consecutive collection periods. Blood hemoglobin, muscle and olfactory bulb carnosine concentration, plasma protein and glutamic-oxaloacetic transaminase activity, and blood urea nitrogen were all unaffected by treatment. Offspring from gilts fed the histidine-free diet had lower blood hemoglobin concentrations than their counterparts from gilts receiving histidine. A tentative recommendation of 0.12% dietary L-histidine would seem justified for gravid swine.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001219:Aspartate Aminotransferases / Q000097:blood; D001806:Blood Urea Nitrogen; D002336:Carnosine / Q000378:metabolism*; D004032:Diet; D004151:Dipeptides / Q000378:metabolism*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006639:Histidine / Q000172:deficiency / Q000378:metabolism*; D008892:Milk / Q000032:analysis; D009132:Muscles / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D009830:Olfactory Bulb / Q000378:metabolism; D011247:Pregnancy; D011270:Pregnancy, Animal; D013552:Swine
chemical_list: D004151:Dipeptides; D006454:Hemoglobins; D006639:Histidine; D002336:Carnosine; D001219:Aspartate Aminotransferases; D009584:Nitrogen