1. Intestinal development was examined in Arbor Acres and Lohmann chicks from one week before hatching until one week after. Changes in morphology and concentrations of DNA, RNA and protein in the duodenal tissue were determined. 2. Villus height and perimeter increased 9 to 11 fold from day 14 of incubation until 7 d after hatching. Arbor Acres chicks had values which were consistently higher than Lohmann chicks. 3. DNA concentration of duodenal tissue increased with age in parallel to the increase in the number of enterocytes per villus. In the pre-hatch period tissue activity as indicated by RNA/DNA, and ribosomal capacity as shown by the RNA/protein ratios, were high for both strains; values for Arbor Acres embryos and chicks were greater than for Lohmann. 4. DNA concentrations, RNA/DNA, RNA/protein and protein/DNA ratios correlate with morphological measurements and can be used as additional criteria for evaluating development in chick intestine. 5. In the last week of incubation and immediately after hatching, intestinal growth appears to arise mainly from cellular hyperplasia and not from cellular hypertrophy. Intestinal development patterns were similar for both strains but growth was more rapid in Arbor Acres chicks.

Development of the small intestine in heavy and light strain chicks before and after hatching

Among the core transitions in medical education is the one from medical school to residency. Despite this challenging transition, the final year of medical school is known as lacking structure and clarity. The authors examine the preparation of medical students for the professional and personal challenges of internship in the context of transition courses. They first describe the development of a residency transition course, offered since 2001 at the University of California, San Francisco, School of Medicine (UCSF), exploring aspects of a needs assessment, course goals and content, core competencies, and course implementation. They then critically analyze the course, judging it successful based on high subjective satisfaction scores and increased perceived preparedness data. Next, the authors discuss the national context of transition courses, perspectives of various stakeholders, and lessons learned from the UCSF experience. Finally, they consider future directions, suggesting that internship transition courses be a standard part of the medical school curriculum.

The key role of a transition course in preparing medical students for internship.

The embryonic and immediate post-hatch developmental period represents a significant phase in attaining quality broiler performance at marketing. An efficient transition period from late term embry...

Early nutritional strategies

In ovo supplementation of poultry embryos was first reported several decades ago, but it is only recently that concerted research has been directed at developing the technology for this process to be routinely used by the poultry industry. Although the technology of in ovo feeding was patented more than 10 years ago, it has not been widely adopted by the poultry industry. This review examines the early development of the enteric system of the poultry embryo; defines and distinguishes between in ovo feeding and in ovo nutrient administration; highlights the importance of early feeding of the chick; and discusses the development of in ovo feeding technology and its effects on hatchability, growth, gut health and immune response of chicks. The range of possible nutrients that can be administered is also explored. The limitations associated with embryo development and nutrient metabolism are highlighted, leading to the prediction of the future role of in ovo feeding in the poultry industry.

Prospects of in ovo feeding and nutrient supplementation for poultry: the science and commercial applications--a review.

Model of physiological stress in chickens 3. Temporal patterns of response

Yolk Sac Absorption and Initiation of Growth in Broilers

Evaluation of the Chemical and Physical Properties of Hardwood Bark Used as a Broiler Litter Material

SUMMARY This study examined hatchery feeding of starter diets differing in amino acid density and moisture on live performance measurements up to 37 d and processing measurements at 38 d. Eggs from a Cobb × Cobb 500 slow-feathering cross broiler strain were set in a common incubator and hatched. Chicks were feather-sexed, placed in 36 chick trays (25 chicks of each sex), and weighed by tray. One of 4 dietary treatments was administered (454 g/tray) in crumble form: 1) no feed; 2) feed containing 1.24% digestible Lys, 0.84% digestible TSAA, 0.80% digestible Thr, 23.2% CP, and 3,080 kcal/kg of ME; 3) feed containing 1.45% digestible Lys, 0.94% digestible TSAA, 0.84% digestible Thr, 26.0% CP, and 3,080 kcal/kg of ME; and 4) treatment 3 plus 100 mL of potable water added to the crumbles 5 min before administration in the trays. Chicks received feed treatments in trays in the hatchery, during transportation to the research facility, and in the research facility until placement (5 h of total tray feeding). Body weight gain at d 7 was increased in birds fed the high density diet alone or in combination with water as compared with birds that were fasted. Subsequent live performance, processing, and small intestine weights, however, did not differ among treatments. Lack of 37-d improvements (average 4.6-lb birds) to early feed allocation may be a result of diet composition, duration of diet allocation, and the genetic strain of bird used, because much literature has pointed to the importance of posthatch nutrition of broilers.

Hatchery Feeding of Starter Diets to Broiler Chicks

SUMMARY Three trials were conducted to examine the efficacy of rice hull ash as a litter material for broiler chickens. Each 42-d trial used the following litter materials: pine shavings, rice hull ash, and rice hull ash blended with pine shavings. In trial 1, pine shavings (PS), rice hull ash (RHA), and a 50/50 blend of PS and RHA were used as the 3 litter treatments. In trials 2 and 3, PS, RHA, PS/RHA (50/50), PS/RHA (70/30), and PS/RHA (70/30 layered) were used as the 5 litter treatments. Body weight, feed conversion, and NH3 production, N, phosphate, and potash in litter were determined at the end of each trial. Body weight and feed conversion were not consistently altered by any of the litter treatments among the 3 trials. Likewise, NH3, N, phosphate, and potash in litter were not consistently altered by any of the litter treatments among the 3 trials. RHA alone or in combination with PS can be used as litter material for broiler chickens with no adverse effects on broiler performance, litter NH3 production, or litter fertilizer value.

T. N. Chamblee

Papers

Yolk Sac Absorption and Initiation of Growth in Broilers

Evaluation of the Chemical and Physical Properties of Hardwood Bark Used as a Broiler Litter Material

Hatchery Feeding of Starter Diets to Broiler Chicks

Evaluation of Rice Hull Ash as Broiler Litter

Effect of Refeeding Following Short-Term Deprivation of Feed or Water, or Both, on Selected Physiological Parameters for Broiler Chickens