Call number: LD2668 .T4 1955 B68 / Master of Science

Studies investigating the effects of feeding diets containing the yeast, Saccharomyces cerevisiae var. boulardii (SCB), and a yeast culture (YC) containing S. cerevisiae were conducted in market turkeys and Medium White turkey breeder hens. Increased utilization of dietary gross energy, N, Ca, P, B, K, Mg, and Mn were observed in poults fed a diet containing 1% YC when compared to the control and 1% inactivated YC diets at 4 weeks of age (WOA). It was concluded that the YC must be "biologically active" in order to affect nutrient retention in poults. Feeding day-old poults diets containing varying amounts of SCB resulted in increased body weights at 3 WOA. Greater body weights and a decrease in the number of mucous-secreting goblet cells per mm of villus height and a decreased crypt depth were observed in poults receiving .02% SCB from 3 to 5 WOA. No dietary differences were observed for either villus height or width. Results indicated that feeding SCB to poults increased body weight and altered gut morphology. Experiments conducted to evaluate the effects of .25% YC on market male turkey performance resulted in contradictory responses. Supplemental YC increased body weights of turkeys at 5, 8, 11, and 14 WOA in one trial, while no differences and depressed body weights from 2 through 17 WOA were observed in two subsequent trials, respectively. Similarly, feed to gain ratios were improved from day-old to 5 WOA in one trial, while no differences and a higher feed to gain ratio was observed from 2 to 5 WOA in the second and third trials, respectively. Results indicated that unelucidated factors may influence the response of market male turkeys fed dietary YC. Consistent results have been observed in two trials on the hatchability of fertile eggs (HFE) from hens of three genetic lines fed .5% dietary YC. Early embryonic mortality (0-10 d of incubation) was reduced when hens were supplemented with YC and the HFE was increased in eggs stored less than 9 days in select hen genotypes. Results indicated that the breeder hen's genotype and pre-incubation storage time are factors to be considered when evaluating a YC in turkey breeder hen diets. / Graduation date: 1994

An experiment was conducted to evaluate a breeder diet containing a yeast culture as a means of improving the reproductive performance of two genetically dissimilar lines of turkey hens (designated as L and H). Two hundred hens of lines L and H, 100 hens per line, were housed in a curtain sided breeder house (10 hens/line/pen). Starting at 31 weeks of age (WOA), the hens were fed either Corn-soy (CS) or Corn soy+yeast (CS+Y,.5% Diamond V Mills "XP" yeast culture, Saccharomyces cerevisiae) diets. Between 33 and 45 WOA, the hens were mated inter se and from 45 to 51 WOA reciprocal line matings were established. Hen reproductive parameters measured between 31 and 51 WOA were, body weight (BW) change, feed intake, feed per dozen eggs, egg production, egg size, fertility, embryonic mortality, and hatchability of fertilized eggs from 7 biweekly egg settings. No differences (P>.05) were observed with yeast culture supplementation of the diet for changes in BW, egg production, egg weight, embryonic mortality, and hatchability of fertilized eggs (n= 5 biweekly hatches) of either line. A significant time by diet interaction was evident only in feed intake. There was an improved (P<.05) hen fertility in line H as a result of feeding the dietary yeast culture. When reciprocal line crosses were established between 46 and 51 WOA, hatch of fertilized eggs (n= 2 biweekly hatches) was substantially improved (p<.05) from hens fed the yeast culture containing diet. The results of this study suggest that there is a genetic factor associated with the feeding of a diet containing a yeast culture to turkey breeder hens. / Graduation date: 1993

Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 21, 2007) Vita. Includes bibliographical references.

Thesis (M.Sc.(Agric.))--University of Pretoria, 2007. / Includes summary. Includes bibliographic references (leaves 75-86).

Two meta-analysis of effects of yeast culture and monensin in lactating dairy cows were first performed. Secondly, two experiments were performed to evaluate the effects of live yeast (LY) or monensin (M) or both (LY+M) on gas production and fermentation by rumen micro-organisms in vitro in low (40 %) and high (60 %) concentrate diets of dairy cows. Rumen contents were collected from one cannulated lactating Holstein cow. Gas production was measured from 0 to 48 h of incubation. Volatile fatty acids and ammonia nitrogen concentrations were measured after 48 h. Meta-analysis of monensin indicated decrease dry matter intake (DMI) and increasing milk yield, consequently improving feed efficiency. Meta-analysis of yeast culture did not show improved performance. These results highlighted the importance of the meta-analysis as a useful tool that can be employed to both summarize effects across studies and to investigate factors explaining potential heterogeneity of response. The batch fermentation showed that in high concentrate diet, M significantly increased ammonia nitrogen, decreased acetate, but tended to increase propionate concentration (7.9, 63.2, 18.6 vs. 6.3, 66.8, 14.2 mmol/l; respectively). Addition of LY increased acetate concentration (64.2 vs 66.8 mmol/l). Supplementation with M, LY and LY+M reduced total gas production by 37.1, 22.5 and 26.9 %, respectively, compared to control at 48 h. In low concentrate diet, M and LY+M decreased and increased acetate (60.1 and 69.7 vs. 7.1 mmol/l; respectively). Adding LY and LY+M produced 8.6 % less gas, and M treatment 3.4 % more gas than the control. Overall, at 48 h, high concentrate resulted in less gas than low concentrate diets. High concentrate diets showed increased ammonia (7.9 and 6.4 vs. 5.21 and 4.7 mmol/l) decreased acetate (63.0 and 63.2 vs. 67.0 and 69.7 mmol/l) with a tendency to increased propionate (18.6 and 18.9 vs. 14.6 and 14.1 mmol/l) compared to low concentrate in M and LY+M treated diets. These results indicate that the effects of M and LY on rumen fermentation are substrate dependent, the high-concentrate diet showing the greatest response / Agriculture / M. Sc. (Agriculture)

Two meta-analysis of effects of yeast culture and monensin in lactating dairy cows were first performed. Secondly, two experiments were performed to evaluate the effects of live yeast (LY) or monensin (M) or both (LY+M) on gas production and fermentation by rumen micro-organisms in vitro in low (40 %) and high (60 %) concentrate diets of dairy cows. Rumen contents were collected from one cannulated lactating Holstein cow. Gas production was measured from 0 to 48 h of incubation. Volatile fatty acids and ammonia nitrogen concentrations were measured after 48 h. Meta-analysis of monensin indicated decrease dry matter intake (DMI) and increasing milk yield, consequently improving feed efficiency. Meta-analysis of yeast culture did not show improved performance. These results highlighted the importance of the meta-analysis as a useful tool that can be employed to both summarize effects across studies and to investigate factors explaining potential heterogeneity of response. The batch fermentation showed that in high concentrate diet, M significantly increased ammonia nitrogen, decreased acetate, but tended to increase propionate concentration (7.9, 63.2, 18.6 vs. 6.3, 66.8, 14.2 mmol/l; respectively). Addition of LY increased acetate concentration (64.2 vs 66.8 mmol/l). Supplementation with M, LY and LY+M reduced total gas production by 37.1, 22.5 and 26.9 %, respectively, compared to control at 48 h. In low concentrate diet, M and LY+M decreased and increased acetate (60.1 and 69.7 vs. 7.1 mmol/l; respectively). Adding LY and LY+M produced 8.6 % less gas, and M treatment 3.4 % more gas than the control. Overall, at 48 h, high concentrate resulted in less gas than low concentrate diets. High concentrate diets showed increased ammonia (7.9 and 6.4 vs. 5.21 and 4.7 mmol/l) decreased acetate (63.0 and 63.2 vs. 67.0 and 69.7 mmol/l) with a tendency to increased propionate (18.6 and 18.9 vs. 14.6 and 14.1 mmol/l) compared to low concentrate in M and LY+M treated diets. These results indicate that the effects of M and LY on rumen fermentation are substrate dependent, the high-concentrate diet showing the greatest response / Agriculture / M. Sc. (Agriculture)