Lumpkins B.S.,Southern Poultry Research Inc |
Lee M.D.,University of Georgia
Poultry Science | Year: 2010
The gastrointestinal tract (GIT) of each animal species provides a unique niche for specialized intestinal bacterial communities to thrive, and in poultry this is no exception. However, little is known about how the bacterial community varies among these different genetic lines of chickens, especially of those with various growth rates. Therefore, an experiment was conducted to observe and evaluate the changes in the bacterial community and GIT development of a modern multipurpose strain, high-yield strain, and a historic strain, Athens Canadian Random Bred (ACR), of broilers. All birds were fed a standard nonmedicated corn-soybean meal broiler starter diet ad libitum from 0 to 35 d of age. Intestinal measurements and bacterial analysis of the ileum were conducted at 4, 8, 14, 21, and 35 d of age. Bacterial DNA was isolated from the digesta, and the distribution of bacterial 16S rRNA sequence polymorphisms was analyzed by a combination of denaturing gradient gel electrophoresis and terminal restriction fragment length polymorphisms. The multipurpose chicks performed the best from 0 to 14 d of age; however, overall performance was similar for the multipurpose and the high-yield broilers. The ACR birds had the poorest performance at all periods measured. The overall relative weight of the jejunum and ileum was not different between the 3 genetic lines, but the ACR birds had the longest relative jejunum and ileum lengths. Furthermore, the multipurpose birds had the longest villi height, whereas the ACR birds had the shortest villi height in the jejunum and ileum at all measuring periods. Based on denaturing gradient gel electrophoresis, the multipurpose and high-yield broilers had similar bacterial communities at all ages. Regardless of the genetic line of broiler, the bacterial community changed with age. Performance, GIT measurements, and bacterial community of the ACR differed compared with the modern broilers. The results indicate that the different genetic lines of broilers have varying rates of intestinal development, which may affect performance and the bacterial community. © 2010 Poultry Science Association Inc.
Knap I.,Chr. Hansen A S |
Lund B.,Chr. Hansen A S |
Kehlet A.B.,Chr. Hansen A S |
Hofacre C.,University of Georgia |
Mathis G.,Southern Poultry Research Inc
Avian Diseases | Year: 2010
Thúree studies were conducted using Clostridium perfringens as an intestinal challenge to produce necrotic enteritis (NE). The studies consisted of two battery screening studies and one production study in floor pens, which were used to test the effect of the addition of Bacillus licheniformis (DSM 17236) spores at different doses and feeding periods in comparison to birds fed diets with subtherapeutic levels of virginiamycin (15 g/ton feed). In all three studies the use of B. licheniformis (1.6 × 1068 × 10 7 CFUs/g) or virginiamycin (15 g/ton feed) showed no difference in effect with regard to feed conversion ratio, weight gain, NE lesion score, and NE mortality. In the two battery studies, both treatments showed a significantly decreased feed conversion ratio, increased weight gain, reduced NE lesion score, and NE-reduced mortality compared to the nonmedicated C. perfringenschallenged group. In general, none of the treatments performed as well as the no-challenge group. The present data indicate that the use of B. licheniformis spores as a probiotic or direct-fed microbial could be an alternative to adding medication to the feed to overcome NE under commercial-like conditions and could therefore be of direct use in preventing antibiotic-resistant pathogens in chickens. © 2010 American Association of Avian Pathologists.
Jenkins M.C.,U.S. Department of Agriculture |
O'Brien C.N.,U.S. Department of Agriculture |
Fuller L.,University of Georgia |
Mathis G.F.,Southern Poultry Research Inc |
Fetterer R.,U.S. Department of Agriculture
Veterinary Parasitology | Year: 2014
Standard methods of determining the ionophore sensitivity of Eimeria rely on infecting chickens with an isolate or a mixture of Eimeria spp. oocysts in the presence of different anti-coccidial drugs. The purpose of this study was to develop a rapid in vitro method for assessing salinomycin and monensin sensitivity in Eimeria tenella. Cultures of MDBK cells were grown to 85% confluency, and then inoculated with excysted E. tenella laboratory strain (APU-1) sporozoites in the presence of different concentrations of salinomycin or monensin. At various timepoints, the monolayers were fixed for counting intraceullar sporozoites, or were subjected to DNA extraction, followed by molecular analysis using quantitative (qPCR) or semi-quantitative PCR (sqPCR). Preliminary experiments showed that 24. h was the optimum time for harvesting the E. tenella-infected cell cultures. The average number of E. tenella sporozoites relative to untreated controls displayed a linear decrease between 0.3 and 33.0. μg/ml salinomycin and between 0.3 and 3.3. μg/ml monensin. A similar pattern was observed in the relative amount of E. tenella DNA as measured by sqPCR. A linear decrease in the relative amount of E. tenella DNA was observed over the entire range of salinomycin and monensin concentrations as measured by qPCR possibly reflecting the greater sensitivity of this assay. Comparison of sporozoite counting, sqPCR, and qPCR signals using a criterion of 50% inhibition in sporozoite numbers or level of PCR amplification product showed good agreement between the three assays. E. tenella field isolates (FS-1 and FS-2) displaying resistance to salinomycin and monensin were evaluated in the in vitro assay using qPCR and sqPCR. Compared to E. tenella APU-1, the E. tenella FS-1 and FS-2 isolates showed higher levels of E. tenella DNA at 24. h by both qPCR and sqPCR. This in vitro assay represents a significant advance in developing rapid, cost-effective methods for assessing ionophore sensitivity in E. tenella. © 2014.
Amerah A.M.,Danisco |
Mathis G.,Southern Poultry Research Inc |
Hofacre C.L.,University of Georgia
Poultry Science | Year: 2012
The present experiment examined the influence of xylanase supplementation and a blend of essential oils (EO; cinnamaldehyde and thymol) on performance and Salmonella horizontal transmission in broiler chickens challenged with Salmonella. Two thousand 1-d-old broiler chicks were randomly assigned to 5 dietary treatments (8 pens/treatment of 50 male broilers each). Four dietary treatments were challenged with Salmonella: 1) control, 2) basal diets supplemented with EO, 3) basal diet supplemented with xylanase (2,000 U/kg of feed), and 4) basal diet supplemented with a combination of EO and xylanase (2,000 U/kg of feed). One treatment served as an unchallenged control and was not supplemented with either additive. Broiler starter and finisher diets, based on wheat and soybean meal, were formulated, pelleted, and fed ad libitum. At d 1, before placement, half of the birds from each pen were tagged and dosed with Salmonella enterica serovar Heidelberg (5 × 10 5 cfu/mL). On d 42, 5 random untagged birds from each pen were killed and their ceca removed and tested for Salmonella. Performance data were analyzed as a completely randomized design using GLM. The frequency of positive Salmonella in the untagged birds was compared between treatments by using a chi-squared test of homogeneity. Challenging the birds with Salmonella had no effect (P > 0.05) on any of the measured performance parameters. Xylanase and EO supplementation improved (P < 0.05) the 42-d BW gain and feed efficiency, with no effect (P > 0.05) on feed intake, compared with that of the control treatment. Xylanase supplementation improved (P < 0.05) BW gain and feed efficiency compared with the results of EO supplementation. The combination treatment of xylanase and EO numerically improved BW gain and feed efficiency compared with the xylanase treatment. Xylanase and EO supplementation reduced (P < 0.05) the incidence of horizontal transmission of Salmonella infection between birds by 61 and 77%, respectively, compared with the control. The results of the current study suggested that dietary addition of EO and xylanase could improve broiler performance and contribute to food safety by lowering the incidence of horizontal transmission of Salmonella infection. © 2012 Poultry Science Association Inc.
Zhang G.,University of British Columbia |
Zhang G.,Neova Technologies Inc. |
Mathis G.F.,Southern Poultry Research Inc |
Hofacre C.L.,University of Georgia |
And 3 more authors.
Avian Diseases | Year: 2010
A cage study was conducted to demonstrate the effect of Entegard™REV, a lysozyme-based antimicrobial blend, on the performance of broiler chickens and necrotic enteritis (NE) disease reduction of birds that were challenged with Eimeria maxima and Clostridium perfringens. In the experiment, challenge by the infectious agents without medication resulted in impaired feed consumption, weight gain, and feed conversions and caused high incidence of gross NE lesions and NE mortality rate. Entegard™REV included in feed at 200 g/metric ton (MT) was very effective in reducing negative health effects in the birds after NE challenge, and its ability to control the disease was not statistically different from a commonly used antibiotic growth promotant, bacitracin methylene disalicilate, at 55 g/MT. © American Association of Avian Pathologists 2010.