Eduardo R. Chavez

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A 3-wk feeding trial with 240 sexed, day-old broiler chickens was conducted to determine the efficacy of microbial phytase at different levels of dietary Ca on performance and utilization of minerals in broiler chickens fed a low-P corn-soybean diet. The experimental design was a 3 x 2 factorial arrangement of treatments; Ca at 0.6, 1.0, and 1.25% and(More)
A 3-wk feeding trial with 180 sexed day-old broiler chickens was conducted to study the efficacy of microbial phytase (Natuphos 1000) on growth performance, relative retention of P, Ca, Cu, and Zn, and mineral contents of plasma and bone. Treatments involved a normal P level corn-soybean diet, a low-P diet, and a low-P plus phytase (600 phytase units/kg)(More)
The effect of microbial phytase supplementation on CP and amino acid (AA) digestibility was investigated in a 28-d trial using 360 sexed, day-old broiler chickens fed corn-soybean meal diets. The experimental design was a completely randomized one with a 3 x 2 factorial arrangement of treatments. The variables included P and Ca levels and phytase: P and Ca(More)
Male and female Pekin ducks selected (F2 generation) for greater breast muscle thickness (MT) and an unselected control (C) were used in this study under mixed- or separated-sex rearing. Ducks in the separated-sex program had significantly higher body weights than the birds in the mixed-sex program. The ducks selected for greater breast muscle thickness(More)
Ten crossbred gilts fitted with simple T-cannulas at the distal ileum were used to determine the apparent and true ileal amino acid digestibilities in five different soybean products: extruded, jetsploded, micronized, or roasted full-fat soybeans (FFSB) and soybean meal (SBM). The gilts with an average initial body weight of 36 kg were fed the different(More)
The effect of age at the first mating and herd size were evaluated in the reference Spanish Databank (BDporc) of 37 698 sows born between 1991 and 1995 and with individual lifetime records. The data included dates of births at entrance and culling, first mating, repetitive mating and conception, first farrowing and weaning records. Individual records were(More)
Three experiments were conducted to determine and characterize plasma insulin-like growth factor-I (IGF-I) concentrations in Pekin ducks. Plasma IGF-I in Pekin ducks was assayed in a heterologous radioimmunoassay for human IGF-I. When treated with acid, the response dose of duck IGF-I was parallel to that of human recombinant (r) IGF-I. The effect of line(More)
Female weanling Sprague-Dawley rats were used to examine the changes that occurred in selenium and antioxidant status during the development of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumors. Animals were fed an AIN-76 diet, modified to contain 20% fat (3:1 wt/wt, lard:corn oil) and 0.1, 0.035, 0.1, 1.0, 2.0 or 4.0 mg Se/kg diet. At wk 5, rats(More)
A study was conducted to evaluate the effects of diets containing 3% of either palmitic acid (Diet PA), oleic acid (Diet OA), or linoleic acid (Diet LA) on reproductive performance, fatty acid composition of egg yolk, plasma, and liver, and total plasma phosphorus of Japanese quail. Each diet was fed to 20 individually caged hens from 5 wk of age. A 24-wk(More)
The effects of selenium intake on 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis were examined in rats fed a diet high in mixed fats and representative of that consumed in North America. Six groups of 20 rats were fed an AIN-76 diet modified to contain 20% fat from lard:corn oil (3:1 wt/wt) and various amounts of selenium (0.1, 0.035,(More)