Thesis (M. S.)--Texas A&M University, 2006. / "Major Subject: Poultry Science" Title from author supplied metadata (automated record created on Feb. 23, 2007.) Vita. Abstract. Includes bibliographical references.

Aflatoxins are toxic organic compounds produced by fungi in grains. Moderately contaminated grains that cannot be used as food are often directed to animal feed. Economically-feasible detoxification measures for contaminated feeds are needed. The objectives of this research were to identify effective bentonites as aflatoxin adsorbents and to evaluate the performance of the clays as aflatoxin amendments in feed for broiler chickens. Five bentonite samples from Gonzales, Texas, USA were collected and analyzed against the published selection criteria for aflatoxin adsorbents: aflatoxin adsorption capacity, pH, cation exchange capacity (CEC), organic carbon, particle size distribution, and mineralogical and structural compositions. Two bentonites were identified as potentially good aflatoxin adsorbents based on the analyses. These two bentonites were selected for an in vivo poultry experiment where chickens were fed with aflatoxin-contaminated corn (1400 ppb) to test the detoxification efficacy of the clays. Detailed mineralogy analyses were conducted on these two samples (4TX and 1TX) after size fractionation. Clay 4TX and 1TX contained 87 percent and 65 percent clay, respectively. Smectite was the dominant mineral phase in both clay fractions. Quartz and feldspars were also present in both samples. These minerals are unlikely to cause harmful effects on the chickens. The presence of pyrite and heavy metals in 1TX raised concerns about its use in animal feed. The clays were introduced into feed by mixing the dry bentonite powder with the feed for twelve minutes in a mechanical mixer. The body weight was increased by 21 percent with clay 4TX and 14 percent with clay 1TX in the aflatoxin diet. The concentration of total aflatoxins in liver was reduced by 36 percent with the addition of clays. Liver visual appearance was also improved from pale red to a more reddish color resembling the healthy red liver. All chickens fed clean feed had significantly higher body weights than those fed with highly contaminated feed, suggesting that the clays did not completely eliminate aflatoxin toxicity. The published aflatoxin binder selection criteria were useful for screening bentonites as aflatoxin amendments. The selected bentonites based on the criteria could effectively sequester aflatoxins in vivo. Yet direct mixing of bentonite as dry powder to highly contaminated poultry feed could not eliminate the toxicity of aflatoxins.

The objective of this work was to define the effects of dietary energy intake on broiler fat deposition and metabolism. Fatty broilers are one of the major problems in the broiler industry. The effects of changing calorie to protein (Cal/Pr) ratios, and the addition of cellulose or dried distiller's byproduct (DDBP) in the diet, on abdominal fat deposition, liver lipogenesis and glucose oxidation and broiler performance indicated that the mean body weight of broilers fed narrower Cal/Pr ratio diets (124 and 143 for starter and grower, respectively) were lower (P<.01) than broilers fed diets with mid-Cal/Pr ratios (138 and 160) and wide Cal/Pr ratios (147 and 171). Feed conversion was better (P<.01) for broilers fed the diet with wide Cal/Pr ratio than the broilers fed the diet with narrow Cal/Pr ratio. Abdominal fat deposition increased (P<.001) with wide Cal/Pr ratio than narrow Cal/Pr ratio. No significant differences were found in in vitro liver lipogenesis and glucose oxidation when Cal/Pr ratio was widened. Mean body weight, feed conversion and abdominal fat levels of broilers fed 5% cellulose or 10% DDBP diets were not different when compared to broilers fed diets with the same Cal/Pr ratio without these two feed ingredients. The time-course of the deposition of abdominal fat fitted a negative exponential growth curve. The data also indicated that the highest potential for abdominal fat deposition was during the first two weeks of age. When the feed intakes of broilers were restricted for a 6 day period beginning at 1, 2, 3 and 4 weeks of age, the feed efficiencies of all the restricted broilers were significantly improved compared with broilers fed ad libitum. No significant differences were observed in mean body weight between the different treatments. The percentage of abdominal fat in broilers restricted-fed starting either at 1 or 2 weeks old for a 6-day period were lower (P<.05) than broilers fed ad libitum. Feed restriction from days 7 to 12 reduced the adipocyte size but not the number. Feed restriction decreased (P<.05) lipogenesis at 2 and 8 weeks of age. No significant effects were found in lipolysis between the restricted and ad libitum-fed broilers. These studies demonstrate that early feed restriction (days 7 to 12) reduced abdominal fat deposition which is attributed to the reduction in the adipocyte size. Smaller size adipocyte resulted from decreased activity of lipogenesis. / Graduation date: 1991

Research has shown that Salmonella can be prevalent in poultry litter, which can be a source of contamination for newly arrived chicks at the poultry house. Since this organism is a pathogen of concern to the poultry industry, two types of litter amendments and two types of feed additions were created and tested to determine effects of broiler growth, litter moisture and efficacy against Salmonella colonization. Litter amendments consisted of the combination of acidic calcium sulfate (ACS) with either diatomaceous earth (DE) or hydrated sodium calcium aluminiosilicate (HSCAS). Feed additions consisted of differing amounts of sodium bisulfate. For the litter amendment experiments, chicks were placed into pens in isolation rooms. Each litter amendment was applied to 3 pens for replicates of experimental groups. Litter samples were taken weekly from 5 areas in each pen and combined for the determination of Salmonella cfu/g of litter. At 3 and 6 weeks post placement, birds from each pen were euthanized by CO2 asphyxiation. The crop and ceca from these birds were tested for Salmonella cfu/g of crop/ceca or presence/absence of Salmonella. Efficacy of the liter amendments varied in experimental groups on broiler growth characteristics and efficacy against Salmonella. For the determination of sodium bisulfate as a feed addition on Salmonella colonization, birds were placed into 3 experimental groups and placed into respective pens. Two sodium bisulfate experimental groups were used at 0.25% and 0.75%. The other experimental group was the control. Litter samples were taken weekly from 5 areas in each pen and combined for the determination of Salmonella cfu/g of litter, aerobic plate counts, moisture content and pH. Efficacy of the sodium bisulfate as a feed addition varied in the experimental groups on Salmonella colonization, aerobic plate counts, pH and moisture content throughout both trials.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains ix, 39 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 32-37).

Thesis (MSc (Production Animal Studies, Veterinary Science)--University of Pretoria, 2009. / Includes bibliographical references. Also available in print format.

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xxi, 187 p.; also includes graphic (some col.). Includes abstract and vita. Advisor: Karen M. Mancl, Dept. of Food, Agricultural, and Biological Engineering. Includes bibliographical references (p. 169-178).

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographic references (p.100-105).

Thesis ((Ph. D.)--University of Queensland, 2003.

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xi, 111 p.; also includes graphics. Includes abstract and vita. Advisor: Michael S. Lilburn, Dept. of Animal Science. Includes bibliographical references (p. 100-111).