|Donoghue, Ann - Annie|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/1/2004
Publication Date: 1/24/2005
Citation: Solis, F., Balog, J.M., Tellez, G., Anthony, N.B., Hargis, B.M., Donoghue, A.M. 2005. Hypobaric hypoxia in ascites resistant and susceptible broiler genetic lines influences gut morphology [abstract]. 2005 International Poultry Scientific Forum. Abstract No. 164. p. 39.
Technical Abstract: Genetic selection based on rapid growth rates, better feed conversion and heavy body weight for broilers has led to a predisposition to ascites in broiler populations. Sire-family selection was applied to a commercial elite line to produce divergent lines of ascites resistant (<22% ascites mortality, RES) and ascites susceptible (>86% ascites mortality, SUS) broilers by the 7th generation. One objective of this research was to determine the effects of hypobaric hypoxia on gut morphology in these genetic lines. In two separate trials, four hundred and eighty vaccinated, pedigree broiler chickens (40 groups of 12 birds) were randomly assigned to cages in a hypobaric chamber (simulated 2900m above sea level) or a matching local altitude chamber (390m above sea level). On day 42, 2-cm sections of the mid-point duodenum and distal ileum were collected from five chickens in each line at each altitude in each experiment. The sections were fixed in 10% formalin for 72 h and then they were stained with haematoxylin and eosin. From these stained sections, 20 measurements of villus height, villus base, lamina propria and crypt were made at random from different parts of each section. Under hypoxic conditions duodenal surface area was higher (P<0.05) in the RES line (181.3±16.8 and 219± 16.8µm) compared to the SUS line (130.1±10.5 and 134.3±10.5µm, Trials 1 and 2, respectively). Hypoxic conditions also reduced the surface area approximately 60% (P<0.05) in SUS birds compared to SUS birds at local altitude. No differences in ileum morphology was observed for any of the parameters measured. The reduced surface area in the duodenum of birds selected for ascites susceptibility suggests reduced enteric function and may provide clues as to why these birds cannot compensate under hypoxic conditions.