This study evaluated the effects of an antibiotic (oxytetracycline HCL) on reproductive performance of turkey breeder hens. The antibiotic was administered in 1) drinking water or 2) drinking water and intravaginal infusion. Hens were assigned to fertility subclasses (low 0-70%, medium 71-90%, high 91-100%) based on performance from the 7th to 10th week of production. Hens receiving antibiotic in drinking water showed significantly higher apparent fertility than untreated controls, but had significantly higher early embryonic mortality than hens receiving antibiotic in water plus intravaginal infusion. In order to determine the duration of the effect of antibiotic treatment on the variables under study, the eggs were divided into two periods; one containing eggs laid during treatment periods and one week following treatment periods, and the second containing eggs laid two to four weeks post-treatment. The antibiotic in drinking water significantly improved hatchability during the treatment period. The antibiotic in drinking water plus intravaginal infusion had its greatest effect in reducing early embryonic mortality. This treatment had a longer term effect holding embryonic mortality below 10% during treatment and post-treatment periods, while a shorter term effect was observed when antibiotic was administered only in drinking water. In the latter case early embryonic mortality increased significantly during the post-treatment period compared to the treatment period. No correlation was found between mycoplasmal or bacterial population and fertility subclass or antibiotic treatment. Hen day and hen housed production, body weight, feed consumption, feed consumed per egg, egg weight and specific gravity were unaffected by antibiotic treatment. / M.S.

Two experiments were conducted with a total of 1,728 Large White turkeys to determine the relative potencies of four methionine compounds on an equimolar basis. A 28% protein basal diet composed primarily of ground yellow corn, dehulled soybean meal, and meat and bone meal was supplemented with DL-methionine (DL), sodium salt of DL-methionine (MENA), methionine hydroxy analogue calcium salt (MHAC), or methionine hydroxy analogue free acid (MHAA) at the .06, .12, .18, .24, or .3090 level of added methionine. Each of these 20 diets was fed to two pens of poults of each sex (9 birds per pen), and the basal diet was fed to eight pens of each sex from one day to sevenweeks of age in each experiment. From the combined six-week body weight data, MENA was 104.7 (86.1, 123.3), MHAC 101.8 (83.5, 120.1), and MHAA 92.590 (74.9, 110.1) as potent as DL (with 9590 fiducial limits) by the slope ratio procedure. No differences were detectable among the methionine products. The extra one degree of freedom associated with the nonlinear procedure accounted for 4.8 and 10. 7% of the residual variation in Experiments 1 and 2, respectively. Relative potencies were obtained for MENA of 110.3 and 115.6, MHAC of 100.4 and 88.1, and MHAA of 89.7 and 112.390 in Experiments 1 and 2, respectively. Two additional experiments were conducted using a total of 1,680 poults to study the relationships of methionine, choline, and sulfate in practical-type diets. A 6 x 2 x 2 factorial design was used involving increments of .0690 DL-methionine from 0 to .3090, 0 or .20% choline chloride, and 0 or . 10% potassium sulfate. The variables were added to a 21 90 protein basal diet containing 61% ground yellow corn and 32% dehulled soybean meal to which no supplemental choline or sulfate was added. Each of the 24 diets was fed to two pens of medium-type turkeys of each sex (9 birds per pen) from four to eight-weeks of age in the first experiment, and to two pens of Large White turkeys of each sex (9 and 8 birds per pen for males and females, respectively) from three to seven-weeks of age in the second experiment. From the addition of .06% and .12% DL-methionine, body weight gains were increased 11.0 and 16.5% in the first experiment, and 8.9 and 13.690 in the second experiment, respectively. In addition, methionine increased feed consumption about 1/3 these amounts, and feed efficiencies 1/2 these amounts. The addition of choline or sulfate failed to significantly increase these parameters, even in the absence of methionine. No significant interactions were observed among the dietary variables in either experiment. / M. S.

To compare the effect of a standard commercial trace mineral dietary program to low levels of organic minerals on turkey performance, mineral excretion, bone strength, and carcass yield, day-old Hybrid poults (n=1,224) were randomly distributed to one of four treatments with 9 replicates. Experimental treatments consisted of: standard inorganic (SI) with a commercial supplementation program (Mn, Zn, Cu, Se), reduced inorganic (RI) with 10% level of SI, and two organic regimens of Bioplex®/Sel-Plex® (at the same level of RI during period 1 and 2 and at 2/3 of RI for period 3, 4, 5, and 6, or at the same level of RI for entire trial). Body weight (BW), body weight gain (BWG), feed conversion ratio (FCR), and feed intake (FI) were evaluated and fresh excreta were collected at d 28, 49, 70, 84, 105 and 133. Tibias and femurs were collected at d 49, 84 and 133. Trace mineral concentration in litter and carcass yield were determined at d 133. Overall, there was no significant effect on BW, cumulative BWG, FCR, or FI due to treatments (P < 0.05). The contents of Mn and Zn in excreta and litter were significantly reduced (P < 0.05) in Bioplex®/Sel-Plex® or RI diet compared to SI during the study. Cu excretion was significantly reduced at d 84 and 133. Tibias from the SI treatment had increased bone strength at d 49. Carcass yield at processing was significantly improved (P < 0.05) by feeding Bioplex®/Sel-Plex® treatments compared to the SI diet. To investigate the effect of organic or inorganic Zn combined with other trace minerals on turkey performance, immune response, and intestinal development, a 2 by 4 factorial design was utilized with coccidia vaccinated and non-vaccinated and 4 dietary treatments varying in level and source of Zn with Mn, Cu, and Se. A total of 2,376 day-old Hybrid turkeys were assigned to one of the combinations with 9 replicates of each. Dietary treatments consisted of: 1) standard inorganic (SI), Zn (150 ppm) with Mn (165 ppm), Cu (10 ppm), and Se (0.2 ppm); 2) reduced inorganic (RI), Zn, Mn, and Cu at 10% of SI, and Se at 0.2ppm; 3) organic 1 (O1), at the same level of RI; 4) organic 2 (O2), Zn (30 ppm) with the same level of Mn, Cu, and Se as O1. Body weight, BWG, FI and FCR were determined weekly. Bursa, thymus, and spleen were weighed, and duodenum and jejunum were collected at d 7, 14, 28, and 42. Peripheral blood was collected for T-lymphocyte populations on d 21, 28, and 42. Cumulative FI was influenced by vaccination (P=0.003). Cumulative BWG and BW were significantly decreased by vaccination except on d 14. Cumulative BWG increased in poults fed RI compared with those fed O2 (P=0.03). Poults fed O2 had significantly decreased BW when compared with RI after d 28. Cumulative FCR was not affected by diet and vaccination. Vaccination increased spleen weight on d 7 and thymus weight on d 42 (P < 0.05). The birds fed O2 had increased thymus weight when compared with those fed SI at d 7 (P < 0.05). The vaccinated poults had higher numbers of CD4+ T-cells than non-vaccinated birds on d 28 and d 42 (P < 0.05), and an interaction between diet and vaccination was observed (P < 0.05). Compared to non-vaccinated poults, CD4+/CD8+ ratio was significantly increased in vaccinated poults on d 42 (P = 0.0475). The villus height in vaccinated birds was significantly increased in the jejunum (P = 0.0012), but diets did not affect intestinal morphology. In summary, using low levels of organic or inorganic trace minerals is adequate to maintain turkey performance and immune response and decreased trace minerals excretion. / Ph. D.

Host defense peptides (HDPs) are a large group of small positively charged peptides that play an important role in innate immunity. Their role is more critical at early ages when other components of the immune system have not fully developed. There are three classes of avian HDPs: avian beta defensins (AvBDs), cathelicidins (Cath) and liver-expressed antimicrobial peptide 2 (LEAP-2). The objective was to compare expression of HDPs in male turkey poults at day of hatch (D0), D7, D14, D21 and D28 from the thymus, spleen, bursa, duodenum, jejunum and ileum. The expression of AvBD1, AvBD2, AvBD8, AvBD9, AvBD10, AvBD13, Cath2, Cath3 and LEAP-2 was measured using qPCR (n=6 birds/tissue/age). Data were analyzed by one-way ANOVA and Tukey's test, and significance considered at P ≤ 0.05. AvBDs and Caths exhibited greater expression in immune organs than intestinal tissues, with the greatest expression of AvBDs observed in the spleen. The intestinal tissues showed very low expression of AvBDs except for AvBD10 at D0. Similar to AvBDs, Caths expression in the immune organs was greater than the intestinal tissues with the spleen having the greatest expression among immune organs. Conversely, LEAP-2 showed greater expression in the intestinal tissues than in the immune tissues, which showed very low LEAP-2 expression unlike other HDPs. Understanding the differential expression of HDPs could reveal the innate immune status of poults, and may subsequently allow improvement of their health through appropriate mitigation strategies. / Master of Science

The objectives of this study were to develop MAP conditions, using mixtures of oxygen (O₂) and carbon dioxide (CO₂), to prolong the shelf-life of ground turkey thigh meat. The effect of fat level and effectiveness of natural antioxidants were evaluated. Product quality was determined semi-weekly by sensory, microbial, chemical, and instrumental analysis to evaluate rancidity, and sensory flavor changes. Thiobarbituric acid (TBA) tests were conducted to objectively measure changes in oxidative rancidity. Microbial analysis included psychrotrophic, lactic acid, and anaerobic bacteria enumerations, pH determinations were conducted to evaluate the effects of each treatment on the meat. Instrumentation color analysis CIE L* a* b* values were determined to measure color changes. Test results indicate the pH changed significantly only in the air packaged samples. Psychrotrophic, lactic acid and anaerobic bacteria counts were significantly lower (P<0.05) in the 100% CO₂ packaged samples, than all other treatments and the control. Low TBA values, less than 4, were found with the 100% CO₂ samples. Sensory evaluation found the 80% O₂/20% CO₂ and 60% O₂/40% CO₂ packages were no longer acceptable at day 14, and air samples were unacceptable at day 18. The 100% CO₂ sample maintained acceptable over-all taste throughout the test period. Colorimeter values did show the 100% CO₂ atmosphere caused discoloration of the product during the first week. Fat level did not affect microorganism growth or shelf-life extension. Rosemary oleoresin was effective as an antioxidant. TBA values of rosemary treated samples remained under 1.0 for the entire 28-day storage period. / Master of Science

This research was designed to investigate the effect of Modified Atmosphere Packaging (MAP) on the shelf life of refrigerated, cubed, turkey thigh meat. Modified atmospheres of 25% carbon dioxide and 75% nitrogen and 20% carbon dioxide, 60% oxygen, and 20% nitrogen were used for MAP1 and MAP2 respectively. All sample packages, MAPl, MAP 2 , and Air Control, were stored at O.5°C. Headspace gas analysis, color measurement, sensory evaluation, aerobic plate count, and oxidative deterioration of fat were examined over 21 day of storage. Microbiological spoilage was significantly delayed by modified atmosphere treatments. MAP1 delayed fat rancidity while MAP2 increased rancidity because of the high amount of oxygen. The redness of turkey thigh meat was increased in both MAPs. MAP2 showed the highest a values up to storage day 12 and then MAP1 had the highest a values on storage days 16 and 21. Sensory evaluations showed preferences for MAPs in all variables: color, appearance, and odor. ThUS, modified atmosphere treatment 1 (MAP1) demonstrated the best effect on the extension of the shelf life of turkey meat in this study. / Master of Science

A 2 x 2 x 4 factorial experiment utilizing 640 male Large White turkeys was conducted to determine the effects of neonatal/juvenile heat stress and tryptophan supplementation upon growth to 129 days of age, as well as meat quality and brain neurotransmitter levels. Treatments consisted of neonatal heat stress (36 continuous hours at 38 C) starting at 5 days of age, juvenile heat stress (8 hours a day at 38 C for 5 consecutive days) starting at 106 days of age, and tryptophan supplementation (0, .1, .2, and .3 % added to the diet) from 112 days of age to market (129 or 138 days of age). Feed consumption, weight gain, and mortality were l recorded and selected meat quality measurements and brain neurotransmitter levels were determined. Weight gain and feed consumption were significantly reduced by juvenile heat stress treatment while early stress, late stress (EL) treatment significantly increased mortality as compared to CC treatment during this period. Such findings revealed that neonatal heat stress did not reduce losses due to heat stress at market age. After live haul, (129 days of age), EC birds had significantly greater cooking loss as compared to birds of the other three treatments and CC birds had significantly larger thigh weights than EL treated birds. In birds analyzed at 138 days of age, CL treatment resulted in a significantly higher Hunter L-value (lightness) in pectoralis major tissue as compared to CC treatment, indicating a darkening of pectoralis musculature due to juvenile heat stress treatment. Tryptophan supplementation resulted in no significant differences in food intake, body weight, or body weight gain. Serotonin, 5 hydroxyindole acetic acid (5-HIAA), and norepinephrine levels increased linearly with dietary tryptophan supplementation in the four brain regions analyzed while linear increases in L-dihydroxyphenylalanine (L·DOPA) occurred in all regions analyzed except for the cerebellum due to Lâ tryptophan supplementation. Plasma levels of serotonin also increased in a positive dose-response fashion while tryptophan supplementation at all levels significantly reduced norepinephrine levels as compared to the basal diet. The addition of .1% tryptophan to the tinisher diet significantly increased carcass weight and thigh weights while no significant differences occurred in breast protein and ether extract, or in either pectoralis major and biceps femoris shear or Hunter color values due to supplemental tryptophan. / Master of Science

Population density as high as 0.70 square foot per bird had no apparent effect on growth, feed conversion, mortality, and market quality on Medium White turkeys to 10 weeks of age. At 14 weeks of age body weight and feed conversion decreased slightly for both males and females allowed less than 0.85 square foot per bird. Market quality and mortality were unaffected for both sexes allowed less than 0.85 square foot per bird. It was noted that consideration had to be given to litter management when high density production methods were practiced because wet litter at decreased floor space levels may contribute to potential disease outbreaks and added cost of dry litter for replacement. Both males and females reared on range were significantly heavier at 18 and 22 weeks of age than those reared in confinement at two and three square feet per bird. Bird density of two square feet per bird in confinement did not adversely affect body weight or feed conversion from 14 to 22 weeks of age. Market quality and mortality were approximately equal for confinement and range reared turkeys. Economic returns above poult and feed cost were found to be approximately 13 and 25 cents higher per square foot of floor space for females and males respectively, when allowed 0.70 rather than 1.30 square foot per bird to 14 weeks of age. / Master of Science

Two experiments were conducted to determine the effect of dietary self-selection of protein and energy on the reproductive performance of Large White turkey hens. The first study examined the effect of self-selection on reproductive performance during a production cycle that started in July and ended in December. Hens were maintained on one of two dietary regimes for a 20-week production cycle. Control birds were fed a conventional diet (18% crude protein, 2700 kcal/kg) which contained nutrients at levels recommended by the National Research Council (NRC, 1984). The remaining hens were allowed to select their diet from two feed sources: one relatively high in protein and low in energy (35% crude protein, 1850 kcal/kg) and the other relatively low in protein and high in energy (8% crude protein, 3220 kcal/kg). Hens fed the split diet produced an equal number of eggs as control hens but consumed significantly less feed (p≤.05). The diet that was selected contained approximately 40% less protein than the control diet (p≤.001) which resulted in significantly increased efficiency of protein utilization (eggs/kg protein) for hens fed the split-diet (p≤.001). In addition, the incidence of broodiness was significantly reduced in the split-diet treatment (p≤.10). Egg weight, fertility, hatchability and hatch of fertile eggs were not significantly effected by the dietary regimes. There was significantly greater body weight loss in hens fed the split-diet (p≤.05). Increasing trends in feed, energy, and protein consumptions were noted over the course of production. For this reason a second experiment was conducted to determine if these trends were the result of seasonal affects, due to changing ambient temperatures, or the result of changes in nutrient requirements of the turkey hen occurring with different stages of production. The second experiment was similar to Experiment 1 except that the production period started in March and ended in July. As in the first experiment, egg production was equal for hens in the two treatment groups. Feed intake and energy intake were not significantly different for hens fed the split and complete diets. However, as in the previous experiment, protein intake was significantly reduced in the split-diet treatment (p≤.001). The incidence of broodiness was again attenuated among split-fed birds (p≤.10). Average daily feed and energy intake appeared to decrease over the course of production which was presumed to be related to increasing ambient temperatures. As in the previous experiment, protein intake increased over the course of production despite increasing environmental temperatures. Therefore, the increased protein selection noted in these two experiments does not seem to be related to hot weather and may indicate an increased protein requirement in the later stages of egg production. Based on the finding that the incidence of broodiness was reduced among hens fed the split-diet, blood sera from hens in both experiments were analyzed for luteinizing hormone (LH) and prolactin (PRL). Although the incidence of broodiness was significantly reduced among birds fed the split-diet, there was no significant difference in serum LH and PRL concentrations. Therefore, the reduction in the incidence of broodiness that was noted in these experiments was not correlated with changes in the blood concentration of these hormones. / Master of Science

Two experiments were conducted to determine the role of the turkey hen’s immune system in the so-called seasonal decline in fertility. Results from Experiment I demonstrated that trauma to the oviduct induced either at the time of the initial artificial insemination, or during subsequent inseminations had no effect upon hen fertility, or serum anti-sperm antibody titers. No differences in fertility were found between hens showing a positive or negative anti-sperm antibody response. Experiment II demonstrated that only relatively infertile turkey hens had antibody positive cells within the uterovaginal sperm storage gland epithelium (UVSG), while fertile turkey hens had no such cells. Antibody positive amorphous material was found within the lumen of the UVSG of relatively infertile, but not fertile turkey hens. Blood serum from relatively infertile hens showed minimal anti-sperm antibody titers. It was concluded that the seasonal decline in fertility in turkey hens is a local not due to a humoral immune response against spermatozoa. However, immune response against spermatozoa appears to exist in the uterovaginal sperm storage glands of the turkey hen, which has a detrimental effect upon fertility / Master of Science