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2.3.3 MeasurementsBody weights were recorded at 11 days of age, 14 days of age and weekly thereafter. Feed refusalswere weighed at the time of bird weighing, and additions to each feeder were allocated on a needsbasis and weighed each time.At 21 days of age, one bird per cage was euthanazed using CO 2 gas for dissection. The proventriculus,gizzard, duodenum, jejunum, and ileum were weighed with and without digesta contents. Gizzard andduodenum digesta pH was recorded. Digesta was collected from the duodenum and immediatelyrefrigerated for particle size analysis. All organs were cleaned of external fat and mesentery beforeweighing. At 35 days of age, the dissection procedure was repeated.At 25d all birds were fasted for six hours, feeds and birds were weighed, and excreta trays placedunder birds for excreta collection. Excreta were collected for three consecutive days at the same timeof day that the trays were placed under the birds on the first day of collections. Daily collections ofexcreta were pooled and frozen at -20˚C. The birds and feeds were weighed at the commencementand completion of excreta collection. Excreta were used for nitrogen corrected apparent metabolisableenergy (AME n ) determination.2.3.4 Marker preparation and administrationChromium mordanted hay (used as a solid phase marker) was prepared according to the methodoutlined by Udén et al. (1980). The prepared hay was ground using a 1 mm screen on a Christy-Hunthammermill, desiccated, and pressed into 1000±5 mg tablets using a manual screw-down tablet press.Cobalt-ethylenediamine tetraacetic acid (Co-EDTA) powder, used as a liquid phase marker, containedin a commercially available 1.0cm 3 gelatine capsule was also used to measure digesta transit time.Cobalt-EDTA was prepared according to the method outlined in Udèn et al. (1980). Birds receivedtwo 1000 mg Cr-mordanted hay tablets each, and one Co-EDTA capsule in a one-off (force-fed)administration. All birds were allowed ad libitum access to feed and water immediately before andafter marker administration. Markers were administered to ten 29d-old birds per treatment over cleanexcreta collection trays, with excreta collected at 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, and 24h post markeradministration for marker retention time and recovery analyses. Samples were frozen after eachaddition of fresh excreta, and until the time of analysis.2.4 Experiment 2Based on the findings of the first experiment, it was concluded that there was an effect of the particlesize of the grain used in the diet. It was postulated that the type of grain used in the diet would alsohave an effect on the performance of the broiler, and thus a second grain of greatest significance to theAustralian broiler industry (wheat) as well as sorghum was used in the second experiment. Thehypotheses for the second experiment were that; the particle size of the grain in the pelleted dietswould affect performance, gut development, and enteric microbial status, irrespective of grain type,and, the aforementioned parameters will be affected by grain type.The second experiment was conducted at the University of New England Animal House facility,located in Armidale, New South Wales, Australia, during September and October of 2005. Armidaleis located at 30˚30'E, 151˚40'S and is approximately 1000 m above sea level. Due to its altitude, anddistance from the coast, Armidale is in a cool-temperate climate zone, with mean daily temperaturesranging between 3.7˚C and 17.6˚C in September, and 7.0˚C to 21.2˚C in October (Australian Bureauof Meteorology, 2006). Climate-controlled rooms were thus needed for the experiment.10
2.4.1 Experimental facilitiesThe birds were housed in two climate-controlled rooms for the brooder phase, and two temperaturecontrolled rooms for the grower phase. Birds were housed in their respective treatments groups from1 day of age until the end of the experiment. All analyses were conducted at the Department ofAnimal Science laboratories, located on the university campus.2.4.2 TreatmentsFour treatments were used in the experiment to test the stated hypotheses. The treatments consisted ofa 2 x 2 factorial, with grain type and particle size comprising the two factors. Within the grain typefactor, the two levels were wheat and sorghum, and within the particle size factor, the two levels werecoarse and fine particle size. The four treatments used were: Fine wheat (WF); Coarse wheat (WC);Fine sorghum (SF), and Coarse sorghum (SC).The diet formulations used were semi-purified, in an attempt to eliminate confounding factors in thediet, such as fibre. The diets were also free of antibiotic/growth promotant and coccidiostat, as theseadditives would most certainly affect the microbial ecology of the digestive tract.2.4.3 Feed preparationApproximately 50% of the wheat and sorghum used for the treatments was ground using a smallroller-mill (Wolf Engineering & Millwrights, Victoria, Australia) powered by a 0.75kW TecoElectrical and Machinery Company Ltd. (Taiwan) motor. Both rollers used, had approximately 2.75flutes.cm -1 , with flutes protruding from the roller by approximately 4 mm, and a 0.5 mm flattened top.The remaining grain was milled using a hammer-mill (JAS. Smith Pty. Ltd., Ballarat, Victoria,Australia), used for small scale grinding, operated at 2500 RPM (approximately 2000 kg.hr -1 capacity)and was powered by a 15kW (25.8A) (Australian Electrical Industries Pty. Ltd., Australia) motor.After milling, and prior to mixing with the remaining ingredients in a small rotary four-blade mixeroperated (at 23 RPM), each of the grains was sieved using a soil sieving machine (custom made forthe University of New England‟s School of Agronomy and Soil Science), vibrating at an approximateamplitude of 3 cm at a frequency of approximately 20 Hz, fitted with a 2.0 mm sieving screen.Screenings collected from under the sieve were used for the „fine‟ treatments, and residue on the top ofthe screen was used for the „coarse‟ treatments.Celite ® was added as a source of acid insoluble ash, as an indigestible marker for nutrient digestibilityanalyses. Cellulose was added to the sorghum diet to serve as an energy diluent, whilst semi-purewheat starch (Fielder‟s Wheaten Corn Flour) was added to the wheat diet to increase themetabolisable energy content.All diets were “cold” pelleted using a 7.5 kW Templewood Hawkesley (Slough, Bucks, England) coldpelleter fitted with a 4.0 mm die, moving at 126 RPM past two pellet cutter blades. The mean pelletlength for all diets was approximately 6mm. The actual feeding trial was conducted as described insection 2.4.1.2.5 Experiment ThreeThe third experiment was held under commercial conditions on rice husk litter to give a „real world‟perspective to the body of research, as Experiments One and Two were conducted under experimentalconditions in cages.The experiment was conducted at the Bartter Enterprises Pty. Ltd. grow-out testing facility, locatednear Hanwood in southern central New South Wales (34.33˚S, 146.03˚E) at an elevation of11
Page 6: diets. The FCR on whole-wheat diet
Page 10 and 11: 2.2.7 Fermentation characteristics
Page 14 and 15: approximately 126m. The experiment
Page 18 and 19: 2.6.6 Digestibility of nutrientsApp
Page 20 and 21: utyldimethylsilyltrifluoroacetamide
Page 22 and 23: High performance size-exclusion chr
Page 24 and 25: 3.1.3 Prebiotic plant extracts for
Page 26 and 27: The ARDRA and partial 16S rRNA gene
Page 28 and 29: WSCs from the two plant sources was
Page 30 and 31: Results from Experiment Two demonst
Page 32 and 33: irds was also 15 % higher than that
Page 34 and 35: The tested plant extracts and prebi
Page 36 and 37: et al., 1992; Nir et al., 1994a). H
Page 38 and 39: The results of the current study su
Page 40 and 41: Cambie, R. C. & Ferguson, L. R. (20
Page 42 and 43: Mitsuoka, T. (2002). Prebiotics and
Page 44 and 45: 9.0 Plain English Compendium Summar

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