Reactive oxygen species-induced damage of cells and molecules is one of the mechanisms responsible for the decline in an animal's performance due to heat stress. Mitochondria are the main producers of cellular superoxide, a process that is sensitive to proton motive force, and this superoxide production can be decreased by mild uncoupling. We studied the effects of heat stress on the production...

The aim of this study was to investigate the role of diet-induced thermogenesis (DIT) in the regulation of feed intake in age-matched broiler and layer cockerels. In addition, the effect of genotype on endocrine functioning and key metabolites of the intermediary metabolism as well as on the expression of muscular uncoupling protein (avUCP) was explored. One-day-old male broiler (Ross) and laye...

Two experiments were conducted to determine the influence of 15.6 and 29.4 degrees C. environmental temperatures on 2- to 4-week broiler lysine requirements. Weights for 4-week-old cockerels were maximum when either 1.10% dietary lysine in the 15.6 degrees C. environment or 1.00% dietary lysine in the 29.4 degrees C. environment were fed. Feed was used more efficiently by 4-week old cockerels f...

Comparative studies were made of semen samples from subfertile RR and normally fertile rr cockerels. These samples were obtained either by abdominal massage or directly from the tip of papillae. The numbers of collected sperm did not differ between genotypes and the sperm from RR cockerels were less motile than those from rr cockerels irrespective of the semen collection method. The uric acid c...

A total of 105, 14 weeks old cockerels weighing 1.49 ± 0.023 kg were used to investigate the effects of Vitex doniana leaf meal (VDLM) on performance, haematological and serum biochemical parameters in cockerels over a seven-week experimental trials. The cockerels were divided into three (3) treatment groups of 0%, 5% and 10% inclusion levels of VDLM in a completely randomized design layout. Th...

BACKGROUND A number of epidemiologic studies have suggested that every year environmental tobacco smoke (second-hand smoke) is responsible for tens of thousands of deaths, mostly from heart disease, in the United States. Environmental tobacco smoke is composed mainly (80% to 85%) of aged and diluted sidestream smoke. The remainder is exhaled mainstream smoke. Among the thousands of compounds th...

Research with adult mammals has shown that the diet-induced thermogenesis (DIT) related to the oxidation of macronutrients has a negative feedback on feed intake (FI), depending on the nutrient considered: proteins are combusted first, then carbohydrates and finally fat, corresponding to their satiating ability. However, previous studies revealed no significant differences in DIT between broile...

In M33 cockerels, the rapid phase of testicular growth and the onset of sperm production were advanced either by increasing daylengths or an interrupted-night photoschedule; they were delayed by constant short days (8L). The results observed under constant long days (16L) were intermediate. In this strain, the cockerels maintained their mean testicular weight during the adult period while their...

The amount of RNA in the testis of immature cockerels has been shown to increase by the injection of pituitary gonadotropins1). The gonadotropic activity of the anterior pituitary of cockerels has been known to show a diurnal change starting at 5 weeks of age2). White Leghorn cockerels were housed in cages under 14hr light (5.00-19.00 hours) per day with food and water available continuously. F...