The prophylactic use of antibiotics is rapidly being phased out of poultry operations. Diseases such as coccidiosis are extremely costly, and typically prevented with coccidiostats and antibiotics. New regulation banning antibiotics is mandating a search for new alternatives, such as probiotics and phytogenic feed additives (PFAs). Two separate studies were performed to evaluate the performance and microbial profiles of commercial broilers fed either PFAs or Eimeria challenged broilers fed probiotics. During the probiotics study, 1056 day-old male Ross broiler chicks were assigned to one of 6 treatments, 8 replicates per treatment, with 22 birds per floor pen in a 2x3 factorial arrangement, with DFM mix and coccidiosis challenge being the main factors. Treatments included a non-infected control (NC), a non-infected low level DFM-fed group (DL), a non-infected high level DFM-fed group (DH), an infected control (PC), an infected low level DFM-fed group (DL+), and an infected high level DFM-fed group (DH+). Performance measurements were taken on d0, d7, d14, d21, and d28. Mucosal scrapings from the ileum were obtained on d7, d14, d21, and d28 to determine microbial profiles. On d15, birds in the three infected groups were challenged with a mixed inoculum containing Eimeria maxima, E. tenella, and E. acervulina. Lesion scores were assessed on d21. Body composition was analyzed via Dual Energy X-Ray Absorptiometry (DXA) on d28. Results indicated a trend (P < 0.1) toward improved D28 body composition, lower Clostridium in DFM-fed challenged broilers compared to PC, and higher Bacillus in DH compared to DH+. Results were not significant for BW, BWG, FI, or lesion scores. The second study evaluated the effects of PFA provided as a dietary supplement over a 6-week period on performance and immune responses in broilers. In total, 1056 day-old male chicks were randomly assigned to 8 replicate pens (22 birds/pen) with 6 treatments including a standard corn/wheat basal diet, a basal with antibiotics, and 4 various combinations of PFA (PHY 1, 2, 3, and 4). Performance was assessed on day 7 (D7), 14, 28, and 42. Starter diet was fed D0-14, grower D14-28, and finisher D28-42. Microbial profiling was assessed on D7, 14, and 42, and body composition measured on D42 using Dual Energy X-Ray Absorptiometry (DXA). Results varied by week, but cumulatively, body weight gain (BWG) per bird was higher in PHY1 and 4, statistically similar to AGP and CTRL. With feed conversion ratio (FCR), PHY2 was higher than any other treatment between D0-42, while all other treatments were similar. PCR results were not statistically significant; however, DXA results indicated a higher lean to fat ratio in birds from PHY1-4 when compared to AGP, indicating an overall leaner bird in PHY treatments. The results of these studies suggest that diets supplemented with DFMs or PFAs result in improved broiler performance. / Master of Science / The prophylactic use of antibiotics is rapidly being phased out of poultry operations. Diseases such as coccidiosis are extremely costly, and typically prevented with coccidiostats and antibiotics. New regulation banning antibiotics is mandating a search for new alternatives, such as probiotics and phytogenic feed additives (PFAs). Two separate studies were performed to evaluate the performance and microbial profiles of commercial broilers fed either PFAs or Eimeria challenged broilers fed probiotics. During the probiotics study, 1056 day-old male Ross broiler chicks were assigned to one of 6 treatments, 8 replicates per treatment, with 22 birds per floor pen in a 2x3 factorial arrangement, with DFM mix and coccidiosis challenge being the main factors. Treatments included a non-infected control (NC), a non-infected low level DFM-fed group (DL), a non-infected high level DFM-fed group (DH), an infected control (PC), an infected low level DFM-fed group (DL+), and an infected high level DFM-fed group (DH+). Performance measurements were taken on d0, d7, d14, d21, and d28. Mucosal scrapings from the ileum were obtained on d7, d14, d21, and d28 to determine microbial profiles. On d15, birds in the three infected groups were challenged with a mixed inoculum containing Eimeria maxima, E. tenella, and E. acervulina. Lesion scores were assessed on d21. Body composition was analyzed via Dual Energy X-Ray Absorptiometry (DXA) on d28. Results indicated a trend (P < 0.1) toward improved D28 body composition, lower Clostridium in DFM-fed challenged broilers compared to PC, and higher Bacillus in DH compared to DH+. Results were not significant for BW, BWG, FI, or lesion scores. The second study evaluated the effects of PFA provided as a dietary supplement over a 6-week period on performance and immune responses in broilers. In total, 1056 day-old male chicks were randomly assigned to 8 replicate pens (22 birds/pen) with 6 treatments including a standard corn/wheat basal diet, a basal with antibiotics, and 4 various combinations of PFA (PHY 1, 2, 3, and 4). Performance was assessed on day 7 (D7), 14, 28, and 42. Starter diet was fed D0-14, grower D14-28, and finisher D28-42. Microbial profiling was assessed on D7, 14, and 42, and body composition measured on D42 using Dual Energy X-Ray Absorptiometry (DXA). Results varied by week, but cumulatively, body weight gain (BWG) per bird was higher in PHY1 and 4, statistically similar to AGP and CTRL. With feed conversion ratio (FCR), PHY2 was higher than any other treatment between D0-42, while all other treatments were similar. PCR results were not statistically significant; however, DXA results indicated a higher lean to fat ratio in birds from PHY1-4 when compared to AGP, indicating an overall leaner bird in PHY treatments. The results of these studies suggest that diets supplemented with DFMs or PFAs result in improved broiler performance.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/83871 |
| Date | 06 February 2018 |
| Creators | White, Mallory B. |
| Contributors | Animal and Poultry Sciences, Dalloul, Rami A., El-Kadi, Samer Wassim, Pierson, F. William |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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