Bolus i.v. injections of 1.2 N HCl elicit a rapid but transient pulmonary vasoconstriction in broiler chickens. In mammals, the pulmonary vasoconstrictive response to bolus acid injection depends on increased synthesis of thromboxane A2; however, the vascular responsiveness of domestic fowl to thromboxane previously had not been evaluated. In the present study, we tested the hypothesis that, if...

Two experiments were conducted to evaluate effects of strain [five in Experiment (Exp.) 1 and six in Exp. 2)] and age (29, 47, and 57 wk in Exp. 1 and 29, 41, and 52 wk in Exp. 2) of commercial broiler breeders on incubation time and chick weight. Highly significant differences in egg weight were found among strains in both Exp. After adjusting for effects of egg weight, significant effects of ...

Induced molting improves egg producing functions in hens. We investigated the mechanism of oviducal regression during induced molting. Involvement of apoptosis and autolysis in the oviducal regression process was analyzed by terminal deoxynucleotidyl transferase (Tdt)-mediated biotinylated deoxyuridine triphosphates (dUTP) nick end-labeling (TUNEL) and an enzyme histochemistry for acid phosphat...

The deposition of dietary folic acid (FA) into the chicken egg is likely regulated by its conversion to 5-methyltetrahydrofolate (5-MTHF), the predominant form of this vitamin in eggs (>80%). Supplementation of 5-MTHF in the laying hens′ diet may therefore enhance total egg folate concentrations. To this end, a study was conducted using equimolar concentration of either FA or 5-MTHF in diets fe...

Broilers (B, 19 d old; 507 ± 40 g BW) and Leghorns (L, 63 d old, 861 ± 87 g BW) had surgical pulmonary artery occlusion (B–PAO and L–PAO; n = 12 each) or were sham–operated (B–SHAM and L–SHAM; n = 12 each). Birds had free access to a commercial broiler feed (NRC, 1994). Medial thickness (%, Thick) was determined in 2 sizes of resistance pulmonary arteries (RPA): ≤ 100 μm (small diameter, SD) an...

In total, 120 one-day-old female Ross 308 broilers were used to evaluate the effect of including oat hulls (OH), sugar beet pulp (SBP), and pea hulls (PH) at levels of 2.5, 5.0, and 7.5% in the diet on lipid metabolism of broilers from hatch to 21 d of age. The OH, SBP, and PH contained 0.7, 11.6, and 5.1% soluble fiber and 70.6, 47.4, and 49.6% insoluble fiber, respectively. The control diet c...

Recent decades were characterized by genetic selection of broiler and layer chickens for enhanced growth rate and meat yield or intensified egg production, respectively. It is to be expected that genetic selection for various traits would also influence embryo development and growth patterns that affect metabolism. The objective of the present study was to examine the effects of broiler (Cobb a...

Experiments were conducted to address recent reports of precocial testis development or testicular hypertrophy induced by the anti-thyroid agent 6-N-propyl-2-thiouracil (PTU) in domestic fowl and rodents. In three experiments, PTU was administered to male turkeys during different stages of development. The PTU was given in the feed at a concentration of either 0.1 or 0.5% and effects on thyroid...

mechanization and automation technologies. By the early 1980s, consumers preferred cut-up and further-processed chickens to the traditional whole bird. Chicken surpassed pork consumption in 1985. Chicken consumption surpassed beef consumption in the United States in 1992. In 1998, USDA required the Hazard Analysis and Critical Control Point (HACCP) process control system program in all large po...

Previous investigations have confirmed the potential effectiveness of various metabolic stimulants and physiological salt solutions in supporting broiler embryogenesis. The current study investigated the effects of the same solutions on chick posthatch performance and tissue nutrient profiles. In the first of 2 trials, 200 μL each of a (i) 0.18 mM carbohydrate electrolyte nutrient (CEN) solutio...