published_or_final_version / Zoology / Doctoral / Doctor of Philosophy

Feed withdrawal is commonly used by commercial egg producers to induce molt and stimulate multiple egg-laying cycles in their flocks. However, the practice can compromise the welfare of the birds by elevating stress, suppressing the immune response and causing abnormal behavior. An alternate molt diet was examined using alfalfa diets, and a series of experiments were conducted to evaluate the physiological, immunological and behavioral responses of laying hens fed these diets. We assessed the changes in the levels of blood plasma metabolites after hens were challenged with 106 colony forming units of Salmonella Enteritidis (SE). Hens fed alfalfa diets displayed similar (P ≥ 0.05) levels of cholesterol, glucose, and total protein when compared to full-fed hens. Reduced levels (P ≤ 0.05) of triglycerides were observed in the alfalfa fed and feed withdrawal hens when compared to the full-fed hens. The immune responses of SE challenged laying hens fed alfalfa diets showed similar (P ≥ 0.05) heterophil to lymphocyte ratios (H: L) to full-fed hens whereas the feed withdrawal hens displayed elevated (P ≤ 0.05) H: L ratios. The feed withdrawal hens displayed reduced (P ≤ 0.05) levels of serum IgY early in the trial when compared to the alfalfa and full-fed hens. The alfalfa fed hens displayed lower levels of acid α glycol protein than the feed withdrawal hens and higher levels than the full-fed early during the trial but returned to levels that were similar (P ≥ 0.05) to the full-fed hens. The hens fed alfalfa diets displayed elevated non-nutritive pecking behavior early in the trial however, this behavior declined to levels similar (P ≥ 0.05) to the full-fed hens by the end of the trial. No differences in aggressive behavior were observed between the alfalfa fed hens and the full-fed hens. Hafnium chloride did not effectively mark the alfalfa diet; however, it can be used to track the passage of corn-soy layer ration. This research suggests that the application of alfalfa as an alternative molt diet can be effective in reducing potentially harmful effects which are usually associated with feed withdrawal.

Feed withdrawal is commonly used by commercial egg producers to induce molt and stimulate multiple egg-laying cycles in their flocks. However, the practice can compromise the welfare of the birds by elevating stress, suppressing the immune response and causing abnormal behavior. An alternate molt diet was examined using alfalfa diets, and a series of experiments were conducted to evaluate the physiological, immunological and behavioral responses of laying hens fed these diets. We assessed the changes in the levels of blood plasma metabolites after hens were challenged with 106 colony forming units of Salmonella Enteritidis (SE). Hens fed alfalfa diets displayed similar (P ≥ 0.05) levels of cholesterol, glucose, and total protein when compared to full-fed hens. Reduced levels (P ≤ 0.05) of triglycerides were observed in the alfalfa fed and feed withdrawal hens when compared to the full-fed hens. The immune responses of SE challenged laying hens fed alfalfa diets showed similar (P ≥ 0.05) heterophil to lymphocyte ratios (H: L) to full-fed hens whereas the feed withdrawal hens displayed elevated (P ≤ 0.05) H: L ratios. The feed withdrawal hens displayed reduced (P ≤ 0.05) levels of serum IgY early in the trial when compared to the alfalfa and full-fed hens. The alfalfa fed hens displayed lower levels of acid α glycol protein than the feed withdrawal hens and higher levels than the full-fed early during the trial but returned to levels that were similar (P ≥ 0.05) to the full-fed hens. The hens fed alfalfa diets displayed elevated non-nutritive pecking behavior early in the trial however, this behavior declined to levels similar (P ≥ 0.05) to the full-fed hens by the end of the trial. No differences in aggressive behavior were observed between the alfalfa fed hens and the full-fed hens. Hafnium chloride did not effectively mark the alfalfa diet; however, it can be used to track the passage of corn-soy layer ration. This research suggests that the application of alfalfa as an alternative molt diet can be effective in reducing potentially harmful effects which are usually associated with feed withdrawal.

Thesis--Ph. D., University of Hong Kong. / Typewritten.

No description available.

Thesis (doctoral)--Ludwig-Maximilians-Universität München, 2003. / Title from PDF t.p. (viewed on May 13, 2006). Includes bibliographical references (p. 145-161).

Salmonellosis affects an estimated 1.4 million people a year with a great majority of cases never being reported. Salmonella Enteritidis (SE) can be found in a variety of foods including poultry meat and eggs. Susceptibility of SE colonization is increased by molting. Induced molting is used in the poultry industry to rejuvenate the hen??s reproductive tract and increase post molt egg quality and production. The most common molting method is complete feed withdrawal. Recent animal welfare pressures have encouraged the industry to seek alternatives to feed withdrawal with one alternative being feeding a high fiber diet like alfalfa. Alfalfa is high in protein, but low in energy which is desirable for a molt diet. Alfalfa??s fermentation properties have been thought to be an inhibitor in pathogen colonization during molting. Including a prebiotic such as fructooligosaccharide (FOS) in the molt diet is thought to further decrease colonization while benefiting the indigenous microflora. Laying hens were molted using alfalfa combined with different ratios of layer ration in an in vivo experiment. The hens responded comparably to the alfalfa molt dietsas they did to feed withdrawal as far as post-molt production parameters were concerned, thus showing that alfalfa was a viable alternative molt diet. Two in vitro studies were designed to evaluate the fermentation properties of alfalfa and layer ration combined with the prebiotic FOS and their abilities to inhibit Salmonella growth. Each treatment was combined with diluted cecal contents and allowed to ferment. The results showed that the most fermentation occurred when alfalfa was the substrate and was slightly increased with the addition of FOS. In addition, combining FOS with alfalfa inhibited Salmonella growth. To integrate these results, an in vivo study was preformed using an alfalfa/layer ration diet from the previous in vivo study with FOS. Volatile fatty acids and lactic acid measurements were made to evaluate fermentation while Salmonella colonization was measured in pertinent organs and in fecal shedding. The results of this study further substantiate alfalfa as a molt diet and conclude that the addition of FOS does, while not statistically significant, further inhibit Salmonella colonization.

No description available.

Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains vii, 101 p. : ill. Includes abstract. Includes bibliographical references.

This project focused on improving the in vitro rearing methods of Toxoneuron nigriceps, an important biological control agent of Heliothis virescens, by supplementing the rearing media with the host hemolymph. T. nigriceps larvae of different ages were incubated in the artificial rearing media. The growth (increase in length and width), development (molting), and survival of the incubated larvae were observed. Changes in osmotic pressure of the rearing media before and after incubation were evaluated. The protein profiles of day 1, 3 and 5 hemolymph samples of the parasitized and unparasitized H. virescens fifth instar larvae, used in the artificial rearing media, were determined. Host hemolymph improved the growth and development of T. nigriceps larvae in the artificial rearing media except in the case of new and early first instar larvae. Osmotic pressure of all media showed a significant decrease after the incubation of the larvae except media incubated with the new first instar larvae indicating that the older larvae absorbed and utilized more of the nutrients from the rearing media than the younger larvae. Growth and development was higher in the semisolid media than in the liquid media. In the artificial rearing media, the late first instar T. nigriceps larvae molted to second instars and a few of them molted to third instars. The early and late second instar larvae incubated in the artificial media also grew well and molted to third instars. Some of the in vitro reared third instar larvae demonstrated behavioral changes that could be expressed as the preparation for cocoon formation or pupation, however neither a cocoon nor pupation occurred. No qualitative differences in the protein titers were detected between hemolymph of the parasitized and unparasitized fifth instar H. virescens larvae. There was a significant increase in the protein concentration in both unparasitized and parasitized H. virescens larvae as the age increased. This increase in the protein concentration showed a positive effect on the growth and development of T. nigriceps larvae indicating that availability of nutrients was an important factor for the growth of T. nigriceps larvae in vitro.