Brett Lumpkins

Evaluation of the bacterial community and intestinal development of different genetic lines of chickens

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.

The Effect of Gender on the Bacterial Community in the Gastrointestinal Tract of Broilers

The effect of gender on the growth, carcass yield, and nutritional requirements of chickens has been well documented, but little is known about how the sex of a chicken affects the bacterial population of the gastrointestinal tract. Therefore, our objective was to evaluate the biodiversity of the bacterial community in the gastrointestinal tract of male and female broilers. An experiment was conducted with Cobb 500 broiler chicks that were vent sexed at 0 d of age and allocated to 8 pens of 25 chicks per gender. All birds were fed a nonmedicated corn-soybean meal starter diet from 0 to 21 d of age. At 3, 7, 14, and 21 d of age, chicks were randomly selected and ileums were taken for bacterial sampling. Bacterial DNA was isolated from the digesta of the ileum, and denaturing gradient gel electrophoresis was used to examine PCR-amplified fragments of 16S ribosomal DNA. Denaturing gradient gel electrophoresis analyses revealed that the bacterial communities separated into 2 gender-specific groups, with less than 30% similarity between populations. Furthermore, as the birds aged, the similarity of the intestinal bacterial community decreased within each gender. Although ileal bacterial population differences within and between genders were noted as early as d 3, differences in growth rate between males and females were not noted until d 21 (data not shown). This suggested that non-growth-related factors influenced the composition of intestinal bacterial communities.

Comparative evaluation of probiotic and salinomycin effects on performance and coccidiosis control in broiler chickens

The annual financial loss to the poultry industry as a result of coccidiosis has been estimated at about US

Calcium Montmorillonite-Based Dietary Supplement Attenuates Necrotic Enteritis Induced by Eimeria maxima and Clostridium perfringens in Broilers

3 billion. The objective of this study was to evaluate and compare the effects of probiotics and salinomycin as feed additives on performance and coccidiosis control in male broilers raised to 42 d of age. The study consisted of 360 Cobb male broiler chickens randomly allocated to 4 groups each with 3 replicates. Group 1: untreated, unchallenged negative control group (NC); group 2: untreated, challenged positive control group (PC); group 3: negative control supplemented with salinomycin 66 mg/kg, challenged group (Sal); and group 4: negative control supplemented with probiotics, challenged (Prob mix). On d 15, all birds (except group 1) were challenged with approximately 75,000, 25,000, and 75,000 of Eimeria acervulina, Eimeria maxima, and Eimeria tenella oocytes, respectively, that were mixed into the feed. Feed conversion ratio and mortality were recorded throughout the experiment. On d 21 and 42, intestinal lesions and litter conditions were scored. On d 7, 14, 21, 28, 35, and 42, oocyst counts were determined from 10 freshly collected fecal samples per pen. The results showed that mortality, litter, and lesion scores at d 21 and 42, and oocyst shedding at d 21 did not differ significantly between the Prob mix and the Sal groups. However on d 28, oocyst shedding was significantly lower in the Sal group than in the PC group but insignificantly lower than the Prob mix group. Body weights of the Prob mix group at d 42 were significantly lower than the Sal group; however, the feed conversion ratio values were similar between the 2 groups. The results of this study showed that probiotics supplementation could be considered as a potential strategy to control coccidiosis in broiler chickens.

Comparison of breeder/layer coccidiosis vaccines: Part 1 -precocity and pathogenicity

Necrotic enteritis (NE) is a poultry disease caused by Clostridium perfringens and characterized by severe intestinal necrosis. The incidence of avian NE has been progressively increasing following the removal of antibiotics from poultry feed. We evaluated the effect of diets supplemented with the thermally-processed clays, calcium montmorillonite (CaMM) on clinical signs, immunopathology, and cytokine responses in broiler chickens using an experimental model of NE consisting of co-infection with Eimeria maxima and C. perfringens. In Trial 1, Ross/Ross chickens were fed from hatch with a normal basal diet or a CaMM-supplemented diet with or without a fermentable fiber, an organic acid, and/or a plant extract, and co-infected with E. maxima and C. perfringens under conditions simulating clinical infection in the field. Chickens fed a diet supplemented with CaMM plus a fermentable fiber and an organic acid had increased body weight gain, reduced gut lesions, and increased serum antibody levels to C. perfringens α-toxin and NetB toxin compared with chickens fed the basal diet alone. Levels of transcripts for interleukin-1β (IL-1β), IL-6, inducible nitric oxide synthase, and tumor necrosis factor-α superfamily-15 were significantly altered in the intestine and spleen of CaMM-supplemented chickens compared with unsupplemented controls (p<0.05). In Trial 2, Cobb/Cobb chickens were fed an unsupplemented diet or a diet supplemented with CaMM or Varium®, each with a fermentable fiber and an organic acid, and co-infected with E. maxima and C. perfringens under subclinical infection conditions. Compared with unsupplemented controls, broilers fed with CaMM plus a fermentable fiber and an organic acid had increased body weight gain, and reduced feed conversion ratio, mortality, and intestinal lesions, compared with chickens fed an unsupplemented diet (p<0.05). Dietary supplementation of broiler chickens with CaMM plus a fermentable fiber and an organic acid might be useful to control avian NE in the field.

Comparison of breeder/layer coccidiosis vaccines: Part 2: Onset of immunity – attenuated vaccines

Abstract Coccidiosis control for breeding and laying chickens requires the development of immunity against multiple Eimeria species. Vaccines approved for use in Europe are precocious (attenuated) strains. Only one precocious vaccine (Paracox® 8) was widely available to breeder and layer producers in the European Union (EU) from 1991 until 2015, with registration in all EU member states except Luxembourg. Recently, 2 new products have been introduced to the market: Hipra Evalon® and a 2 part product originally designated as Huveguard® Start (now designated Mmat) and Huveguard® Plus (now designated NB). Nonattenuated (nonprecocious) vaccines, by contrast, are used in other parts of the world, but are not available in the EU. Three precocious vaccines (Paracox® 8, Evalon® and the combined Huveguard vaccines) were compared to each other and to a nonattenuated vaccine from North America (Coccivac®D2) with respect to precocity and pathogenicity. All 3 precocious vaccines demonstrated significantly reduced oocyst output compared to the nonattenuated breeder/layer coccidiosis vaccine. One vaccine (Paracox® 8) demonstrated oocyst output for all species at 96 h (more precocious), while the other 2 vaccines did not have output until 24 or even 48 h later for individual species (less precocious). When tested at 40X the manufacturers recommended dose (attempting to simulate the field effect of uneven application), all 3 precocious vaccines demonstrated lower lesion scores and better weight gain over the 7 d post challenge compared to the nonattenuated vaccine.

Evaluation of distillers dried grains with solubles as a feed ingredient for broilers

Abstract Coccidiosis control for breeding and laying chickens requires the development of immunity against multiple Eimeria species. Only one vaccine was widely available to producers in the European Union (EU) from 1991 until 2015. Recently, 2 new products have been introduced to the market. The 3 vaccines were compared with respect to the onset of immunity in pen studies, where sample birds were challenged at 21, 25, 28, and 32 d of age to determine the time at which lesion scores became significantly different from unvaccinated controls, the “onset of immunity.” The vaccines were given by oral gavage to eliminate any effect of application methodology on the onset of immunity. “Complete Immunity,” defined as no coccidiosis lesions following challenge, was only achieved for one species (Eimeria tenella) by one vaccine through the final challenge at 32 d. Immunity remained incomplete for all other challenge groups for the duration of the experiment. Onset of immunity was detected by 25 d of age in only one vaccine group for all 5 challenge species tested (E. acervulina, E. maxima, E. tenella, E. necatrix, E. brunetti); and while onset of immunity was detected for some species with the other vaccines by 21 to 32 d of age, neither of the other 2 vaccines demonstrated onset of immunity to all 5 challenge species by the end of the experiment. Delayed onset of immunity could adversely affect pullet weight with early field challenge, as indicated by bird weights taken before and after challenge.