Jamil Williams

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Ad libitum feeding reduces livability and reproductive fitness in broiler breeder hens. Two genotypes, a standard (S) and an experimental dwarf broiler breeder (E), were fed ad libitum (SA and EA, respectively), restricted at 55% of ad libitum feed intake (intermediate restriction) from 6 to 15 wk of age (SI and EI, respectively), or restricted (SR and ER,(More)
Chicken leptin cDNA shows a high homology to mammalian homologous, with an expression localized in the liver and adipose tissue. It is noteworthy, that the hepatic expression is most likely associated with the primary role that this organ plays in lipogenic activity in avian species. As in mammals, chicken leptin expression is regulated by hormonal and(More)
Ovarian regression was induced in hens by infusing 30 micrograms corticosterone/h, feeding diets deficient in Ca2+ or Na+ and by withdrawal of food and water. The weight of the ovary was most severely reduced by the corticosterone infusion. The total number of normal ovarian follicles weighing greater than 0.012 g was not altered by any of the treatments.(More)
1. The objective of this experiment was to study two feeding methods, which could potentially act on the gut microflora, the structure and/or the function of the digestive tract and thereby improve the performance of broilers. 2. Four dietary treatments were studied: a negative control (wheat based) with no additives (C), a positive control with 0.01 g/kg(More)
The production of shell-less eggs was induced in hens to measure the effects of the high demands made by shell formation on the blood minerals and hormones whose concentrations change during egg formation. In control hens laying hard-shelled eggs, the concentration of ionized calcium in plasma decreased at the onset of shell formation, but no change was(More)
The concentrations of prolactin, LH, progesterone and GH were measured in the blood of broody bantam hens. The concentration of prolactin was at its highest when the birds began to incubate their eggs and in six out of nine hens it tended to remain raised until the eggs hatched. The increase in the concentration of prolactin was small: in incubating hens it(More)
The aim of this study was to compare and relate plasma hormone levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P4), estradiol (E2), and the in vitro P4 production capacity of the largest yellow (F1) follicle granulosa cells with the laying performance of 2 genotypes (a standard S line and a dwarf cross-experimental E(More)
(1) Tolerance to ad libitum feeding was compared in three genotypes of broiler breeder hens: a standard broiler breeder fed ad libitum (SA) or restricted (SR), a slow growing 'label' broiler breeder (L) and an experimental dwarf heavy broiler breeder (E). Two similar experiments were conducted in two distinct research centres. (2) Feed intake and body(More)
An evaluation of the insulin-like growth factors (IGF) system in the ovaries of heavy breeder hens during the growing phase was performed to measure the effect of feed restriction. The transcripts of IGF-I, IGF-II, IGF receptor (IGF-R), two IGF binding proteins (IGFBP-2 and IGFBP-5), GH receptor (GH-R) and insulin receptor (I-R) were measured by RT-PCR at(More)
An experiment was conducted to investigate possible differences in plasma hormone levels between females of two lines of chickens selected for high (FL) or low (LL) abdominal fat content. Blood was taken at weekly intervals from 6 weeks of age to sexual maturity, and assays were performed for luteinizing hormone (LH), growth hormone (GH), and estradiol(More)