Soybean meal (SBM) is a staple proteinaceous feedstuff in diets for monogastric animals like poultry and swine. It is known that soybeans contain several anti-nutritional factors that, if untreated, results in decreased quality and bioavailability of amino acids (AA). Thermal processing via heat treatment of soybeans and SBM is essential for inactivation of these anti-nutritional factors; however, over-processing may result in extensive AA damage, particularly lysine. Feeding heat damaged SBM has been proven to be an inefficient source of AA for monogastrics as they cannot be used for any metabolic function. In typical corn-soybean meal diets for pigs and poultry, lysine is the first- and second- limiting AA, respectively. Currently, laboratory procedures are unable to accurately determine digestible lysine in SBM. The objective of this thesis was to compare SBM AA digestibility obtained from 28-day old broilers to values obtained from an in vitro digestion procedure. The correlation between AA concentration in the SBM and its in vivo standardized ileal digestibility (SID) was also analyzed. Twenty-four SBM samples (21 from U.S.A., 2 from Canada, and 1 from Mexico) were analyzed. In vivo lysine SID ranged from 69-93%. Results indicated no correlation (r = -0.16 to 0.21; P = 0.33 to 0.98) between analyzed AA content in SBM and in vivo SID. An increase in lysine SID was associated with an increase in the SID of phenylalanine, leucine, isoleucine, valine, tyrosine, alanine, threonine, glutamate, aspartate, methionine, histidine, and glycine (r² = 0.63 to 0.93; P < 0.001). Poor association was determined between lysine proline, arginine, and serine (r² = 0.14 to 0.43; P = 0.001 to 0.003). Lastly, results indicated no association (r² = 0.00 to 0.08; P = 0.17 to 0.99) between in vivo and in vitro SID for any of the AA tested. In summary, it appears that lysine may be a good indicator for SID estimations for most essential AA; however, SBM content of a particular AA is not a good indicator of its digestibility. Additionally, current in vitro digestibility techniques seemed inadequate in identifying in vivo SID differences and further analytical improvements are needed. / Master of Science

A southern Mississippi broiler complex in an area of high poultry density experienced persistent lower livability and growth performance compared with company averages for the state. It was hypothesized that circulating Infectious Bronchitis Virus (IBV) challenge exacerbated by underlying Infectious Bursal Disease (IBD)-induced immune suppression was the primary contributor to reduced livability and live production performance on certain farms, and that disease challenges were most prevalent on farms in areas of high bird density. A retrospective analysis of data from a three-year period (March 2014 through March 2017) was designed to investigate the role of disease, settlement, geographic, and weather variables in broiler mortality. A database comprising diagnostic variables (processing-age ELISA titers for Infectious Bursal Disease (IBD), Infectious Bronchitis Virus (IBV), Newcastle Disease Virus (NDV), and Reovirus (REO)), settlement variables (downtime, age at processing, average weight at processing, week 1 mortality, genetic line, year, and broiler vaccination programs), geographic variables (number of commercial chicken farms and houses within 1 km, 5 km, 10 km and 15 km radii), and weather variables (average temperature, average heat index, and average humidity for the first 7 days and last 14 days of grow-out) was created and analyzed using univariable and multivariable statistical analyses. First-week mortality, processing age, average processing weight, genetic line, NDV/IBV vaccination program, and heat index in the last 14 days of the grow-out period were found to be significantly associated with flock mortality in this broiler complex (P <= 0.05). The results of this study should guide future management and disease control strategies aimed at reducing broiler mortality. Future studies with more diagnostic data are needed to further investigate the relative contribution of diseases to broiler flock mortality.

Controlling pathogenic presence in broilers has become a priority in the poultry industry to prevent economic losses due to disease and infection, as well as the possible contamination of chicken products. The use of antibiotics reduces the incidence of infections; however, their removal from production initiated the search for suitable alternatives. Probiotic ineed supplements have been widely evaluated as alternatives. Probiotic use has improved broiler performance, reduced pathogenic loads, and stimulated the immune system at later life stages. However, there is still a gap in protection during the first weeks after the chick hatches. The in ovo supplementation of probiotics has the potential of promoting early health benefits and protect the chick against pathogens after hatch. In the present study, the in ovo inoculation of different probiotic species was evaluated. It was determined that the inoculation of higher concentrations of E. faecium (107 cfu/50µL) into the egg improves growth performance and intestinal morphology compared to lower doses (105 and 106 cfu/50µL). It was also determined that not all B. subtilis serotypes are safe for in ovo inoculation, even if recognized as safe for use in feed, due to a high reduction in hatchability. However, certain B. subtilis are safe for in ovo inoculation and regulate the gut microflora through modulations in coliforms and aerobic bacteria after hatch. Lastly, the in ovo inoculation of different Lactobacillus strains does not affect hatchability or growth performance. However, different Lactobacillus species stimulated cytokine production even during the first week of hatch. The bursa of Fabricius morphology was modulated through an increase in follicular area, which could possibly induce higher antibody production against incoming pathogenic challenges. These results indicate that the in ovo inoculation of probiotic bacteria can induce earlier benefits to broiler health through early changes in gut microflora, as well as early stimulation in the immune system. The early protection provided through the in ovo inoculation of probiotics combined with the protection obtained through the administration of probiotics in feed could potentially result in overall healthier broilers and therefore improved performance.

The objectives of this study were first, to investigate the effect of stress and ascorbic acid (AA) supplement during stress on intestinal microflora of broilers and layers, and secondly, to determine nitric oxide (NO) production in intestinal tract of broilers during stress, when supplemented with L-arginine, and NO production in cecal bacteria. The intestinal microflora from broilers and layers were analyzed for bacterial populations during stress and when supplemented with ascorbic acid. In both studies, stress response was induced by adrenocorticotropic hormone (ACTH) via a mini osmotic pump for 7 days, and intestinal samples were collected before and after stress response was induced. During stress, there were no significant effects on intestinal bacterial populations, but changes in intestinal microflora were found in stressed layers and broilers. When AA was supplemented during stress, both short-term and long-term, the microbial population was changed. Cecal NO production during stress, cecal bacterial NO production, and large intestinal NO production when L-arginine was supplemented in broilers were determined as nitrite using Griess reagents. The stress response was induced as in the previous studies. The cecal pouches were collected at day 7 after ACTH insertion. Nitric oxide production by the ceca of broilers during stress was decreased. The cecal bacterial NO production was determined in vitro. The cecal bacteria that produced NO were identified as Lactobacillus fermentum, and Clostridium butyricum. Supplementing with L-arginine, Nù -nitro-L- arginine methyl ester (L-NAME), and sodium nitrate did not affect bacterial NO production on MRS agar incubated anaerobically, but sodium nitrate did affect bacterial NO production on tryptic soy and anaerobic agar incubated aerobically and anaerobically, respectively. L-arginine was supplemented in broiler diet to determine the effect on intestinal NO production and microbial populations. Supplemented with L-arginine affected cecal NO production, but did not affect large intestinal NO production or microbial populations. The positive correlation coefficient between NO contents and bacterial populations was only observed in the large intestine when L-arginine was supplemented in the diet.

No description available.

Previous research evaluated the dLys requirement and the impact of varying dLys and AME on Cobb MV x Cobb 500 broilers during the starter and grower phases, leaving the finisher phase to be determined. Experiment 1 estimated the finisher dLys requirement to range from 0.748-1.32% for males and 0.752-1.292% for females. Male broilers were more responsive to increasing dLys than females, though in general, increasing dLys improved performance and processing. Experiment 2 determined the effects of varying finisher dLys and AME on broiler performance and processing. Increasing dLys improved BWG, FCR, ALI, and breast yield while decreasing FI and fat pad yield. Increasing AME consistently reduced FI and FCR while increasing thigh and fat pad yield. Economic analyses for both experiments demonstrated that maximizing performance was not always economical, verifying the importance of considering feed costs and performance to optimize return on investment for Cobb MV x Cobb 500 broilers.

Coccidiosis is a costly parasitic disease to the poultry industry with multiple prevention methods being explored to control its impact. One approach under development is the use of -glucans, which are carbohydrates from cell walls of various plant species. The first study evaluated the feeding effects of algae- derived -glucans on performance and responses of broilers during a coccidiosis challenge. Cobb 500 broilers (n=1280) were fed a control diet, control supplemented with 150 g/MT Algamune (BG), 100 g/MT Algamune ZPC (BGZn), or 0.01% Salinomycin (Sal). On d 15, challenged birds received mixed Eimeria inoculum. Measurements were taken on d 7, 14, 21, and 28, and lesion scores assessed on d 21. The challenge resulted in reduced BW, and higher feed conversion ratio (FCR) was observed in the challenged birds with Sal and BGZn. Escherichia coli (E. coli) is normally commensal to the gastrointestinal tract, but certain serotypes cause disease in domestic poultry. A subsequent study was conducted to evaluate the feeding effects of algae-derived glucan (1,3 -glucan) on performance of broiler chickens during an E. coli challenge. Cobb 500 broilers (n=900) were fed a control diet, control + 25 mg/kg of -glucan, or control + 100 mg/kg of -glucan. On d 0, litter was sprayed with E. coli inoculum. Measurements were taken on d 7, 14, 21, and 28. -glucan supplementation increased BW gain andlowered FCR. The results from these studies offer some insight to the effects of -glucans on poultry and their potential to offset negative effects caused by infectious challenges. / Master of Science

Broiler nutrition can be affected by many different factors, and diets can be made up of a wide variety of components. Feed enzymes, different Ca sources, and various ingredient particle sizes all contribute to broiler nutritional status and need to be investigated to determine their full effects on the bird. The objective of the first study was to evaluate various Ca sources and microbial phytases using an in vitro assay to simulate broiler digestion. The trial measured total Ca and P, soluble Ca and P, and pH. It involved limestone, dicalcium phosphate, highly soluble Ca (HSC), whey, and a control with no added Ca. Each diet was supplemented with 0 or 500 FTU/kg of phytase 1 or phytase 2. Diets were analyzed for total Ca and P and then were subjected to a gastric phase digestion, including the addition of HCl and pepsin, with incubation times of 5, 10, or 20 min. They were also subjected to a gastric phase and a SI phase digestion, including the addition of HCl, pepsin, NaHCO3, and pancreatin with incubation times of 5, 10, 20, or 60 min. The objective of the second study was to evaluate various particle sizes, Ca sources, and source locations using the same in vitro assay. Large, medium, and fine particle sizes, as well as limestone from 4 different locations and HSC were subjected to the same assays and conditions as in the first trial. These studies suggest that HSC is a highly soluble Ca source, phytase improves P solubility in vitro, fine particle size is more soluble than large particle size in vitro, and location from which the Ca source is obtained can affect Ca and P solubility. The in vitro assay utilized in this study is a fast and cost efficient technique for evaluating and comparing parameters of broiler diets to make recommendations for commercial poultry nutrition. / Master of Science

Two experiments were conducted to determine the effects of high dietary calcium (Ca) on broiler chicks fed low phosphorus (P) diets from either nonphytate (nPP) or phytate P (PP) with or without phytase. The response criteria that were analyzed was bird performance, tibia ash, Ca and P digestibility and duodenal P transporter mRNA abundance. Newly hatched broiler chicks were housed in raised-wire starter batteries (65.8 in2) for 16 d. Each experiment had 12 treatments were replicated 6 times using 8 chicks per cage that resulted in a total of 576 Cobb 500 chicks. Experiment 1 had a 3x2x2 factorial arrangement included 3 P treatments (0.225%nPP, 0.225 + 0.1%P from nPP and 0.225 + 0.1%PP), 2 concentrations of Ca (0.9 vs.1.7%Ca) and either (0 or 1,000 FTU of phytase). Experiment 2 also had a 3x2x2 factorial arrangement but set closer to commercial standards (0.325% nPP, 0.325 + 0.1% P from nPP and 0.325 + 0.1% P from PP), 2 concentrations of Ca (0.9 vs.1.4% Ca) with and without phytase (0 or 1,000 FTU of phytase). Body weight gain (BWG), feed intake, feed conversion and mortality were calculated over the 16d period. On 16d, all remaining chicks were euthanized, and the right tibia was analyzed for tibia ash weight (TAW) in mg/tibia and expressed as a percentage (TAP). All data were analyzed as a 3x2x2 factorial using ANOVA in JMP 14 (P ≤ 0.05). In Experiment 1, the phytase interactions were driving FI, which increased BWG (P ≤ 0.05). However, the phytase interactions did not influence bone mineralization (P ≤ 0.05). So, the diet is potentially more appetizing with phytase supplementation. Calcium x phosphorus interaction was driving bone mineralization, but not influencing BWG or FI (P ≤ 0.05). Additionally, bone mineralization was impacted when additional P was put into high Ca diets (P ≤ 0.05). Phytase upregulated P transporter mRNA abundance in normal Ca diets, but the results were muted in high Ca diets (P ≤ 0.05). Experiment 2 used more practical P and Ca conditions to validate the responses from Experiment 1 with the understanding that the potential responses would be blunted. The addition of phytase improved tibia ash when Ca and P were unbalanced (P ≤ 0.05). High concentrations of Ca lowered BWG and FI, but again the addition of phytase to the diet had a more beneficial effect (P ≤ 0.05). Diets with reduced P had an improved P and Ca digestibility and upregulation of P transporter mRNA abundance (P ≤ 0.05). Also, the addition of phytase improved both P and Ca digestibility and downregulated P transporter mRNA abundance (P ≤ 0.05). Overall, both experiments exhibited that source of P did not influence performance but did influence tibia ash. High calcium had a negative effect on performance and digestibility. However, phytase was able to ameliorate negative impacts of high calcium diets. The multiple interactions of Ca, P and phytase indicate a complex relationship among the three factors that require balancing when looking for optimal conditions commercially, especially to maximize performance and skeletal health while balancing cost and environmental considerations. / M.S. / Phosphorus and calcium have many important functions within the body including energy metabolism, cell signaling, bone development and mineralization. When deficiencies of these minerals are seen in broiler chickens a decrease in skeletal health will be one of the first visual signs, where commercially will show up as leg issues. However, meeting the dietary requirements for P and Ca is not a simple task. A considerable amount of P in poultry diets is in the form of phytate P, which is an organic form of P that is hard to digest by the bird. In most cases inorganic P must be fed to meet the broiler requirements for P because its easily absorbed by the animal. Another way to increase the utilization of these minerals is with the supplementation of phytase into the diet. Supplementing phytase allows for a decrease in the amount of inorganic P being added to the diet. The decrease of inorganic P put in the diet saves industries money and is more beneficial for the environment. The addition of phytase also increases the utilization of Ca from the diet, which is brought into consideration during the formulation of the diet. However, there is still a potential for over supplementation of Ca commercially if there are feed mixing errors or high concentrations of Ca from new feed additives. Over supplementation of Ca can lead to many issues which include reduced nutrient digestibility, reduced performance, and an influence on the effectiveness of phytase. Therefore, the effects of feeding high dietary Ca on broiler chicks fed phosphorus from either nonphytate P or phytate P sources with or without phytase were determined with a focus on bird performance, tibia ash, Ca and P digestibility and duodenal P transporter mRNA abundance. Across both experiments source of P did not influence performance but did influence tibia ash. High calcium had a negative effect on performance and digestibility. However, phytase was able to ameliorate negative impacts of high calcium diets. The multiple interactions of Ca, P and phytase indicate a complex relationship among the three factors that require balancing when looking for optimal conditions commercially, especially to maximize performance and skeletal health while balancing cost and environmental considerations.

The role of nutrition in providing optimal broiler growth and intestinal health is essential, especially during stress or disease challenge. Feed enzymes are useful for improving performance of poultry, particularly when nutrition, management, or health status is not favorable. The objective of the following experiments was to evaluate the effect of dietary phytic acid (PA) and phytase on the performance and intestinal health of birds that were vaccinated with a live coccidial oocyst vaccine. For each experiment, half of the chicks were spray-vaccinated at day-of-hatch with Coccivac®-B and grown out in floor pens with ad libitum access to diets formulated to meet Cobb nutrient recommendations. In the first experiment, birds were given one of three diets that included different levels of a PA solution to obtain dietary PA levels of 0.74, 0.87, and 1.12% for low, medium, and high PA diets, respectively. In the second experiment, two levels of PA were included to obtain dietary PA levels of 0.75 and 1.05% for low and high PA diets, respectively. In addition, phytase was added over the top to half of the diets at 1000 FTU/kg, resulting in four diets: low PA without phytase, low PA with phytase, high PA without phytase, and high PA with phytase. Live performance parameters including body weight, body weight gain, feed intake, feed conversion, and mortality were measured as well as tibia ash (experiment 2) and indicators of small intestinal health including morphology, apparent ileal amino acid digestibility (IAAD), and pH (experiment 2). The results presented here indicated that giving broilers vaccinated against coccidiosis a medium level of PA was detrimental to feed intake, body weight gain, and it induced necrotic enteritis (P ≤ 0.05). Adding phytase on top of nutritionally adequate diets did not improve performance (P ≥ 0.05), but did improve (P ≤ 0.05) apparent IAAD and morphology of the small intestine, especially in younger birds. In addition, it has been determined that important considerations in diet formulation also can include the phytate: protein as well as calcium: total phosphorus ratios, as these may critically affect how phytate impacts bird health and performance. / Ph. D.