Animal & Avian Sciences Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2741
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Item The Effects of Tryptophan and Probiotic Treatment on Behavior and Production Parameters of Laying Hens(2021) Bonilla Carrero, Paola Ivette; Dennis, Rachel L; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Dietary supplementation can impact behavior expression through microorganism’s activity in the gut microbiome and influence productivity in animal husbandry. Adding supplements to production animals’ diet can impact behaviors and productivity via gut-brain axis activity. We investigated the effects of either probiotic or antibiotic supplementation in addition to the effects of additional tryptophan (Trp) on overall behavior and production parameters. White Leghorn chickens (n=12) were supplemented with six dietary treatments in a 2 x 3 factorial design: probiotics (1 x 109 CFU/L) or the antibiotic erythromycin (125 mg/L) in combination with either normal (0.16%) or high (0.48%) Trp in drinking water. Results indicate that probiotics with tryptophan increased locomotion (P = 0.04), social (P = 0.04), and eating behavior (P = 0.02). Antibiotics with tryptophan increased fat pad (P = 0.04) and heart weight (P = 0.04). Supplementation affected behavioral expression of normal, comfort, and pecking behavior, potentially impacted by metabolic competition at the level of the gut microbiome.Item Characterization and Control of Aggression and Reproduction in the Male Clouded Leopard (Neofelis nebulosa)(2012) DeCaluwe, Heather Burton; Ottinger, Mary Ann; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Clouded leopards are a striking and elusive cat species whose secretive nature has made it difficult to gather information on population statistics and behavior in the wild, where the population is in decline. While captive populations are intended as a hedge against extinction, breeding clouded leopards ex situ has been a challenge, primarily due to extreme male aggression toward females. Despite the importance of aggression in this species, there has as yet been no systematic study characterizing the basis of aggressive episodes. Two mechanisms seem to underlie the aggressive behavior in clouded leopards: degree of anxiety and circulating testosterone levels. Three studies were conducted to characterize mechanisms modulating aggression in male clouded leopards. In Study 1, sixteen adult male clouded leopards were categorized as `anxious' or `calm' using a keeper questionnaire and fecal endocrine (androgen and glucocorticoid) profiles; these measures were correlated with behavior rates and frequencies before, during, and after a series of behavioral reaction tests aimed at assessing an individual's response to stress-inducing situations. In Study 2, the behavioral and endocrine responses to the same tests were compared in the same clouded leopards following three treatments: 1) an anxiety-reducing psychotropic drug (clomipramine, n = 4); 2) a gonadotropin releasing hormone agonist (deslorelin, n = 5), or 3) no treatment (n = 4). In Study 3, the long-term effects of the drug treatments on spermatogenesis and hormone concentrations were compared in clouded leopards (n = 2/treatment) and domestic cats (n = 5/treatment), a model for non-domestic felid reproduction. Studies revealed important findings about the basis of aggressive behavior in male clouded leopards. First, two of the behavioral reaction tests - `mirror image stimulation' and `unfamiliar people' - were effective tools for evaluating temperament and eliciting a behavioral response. Second, treatment with both clomipramine and deslorelin reduced anxious and aggressive behaviors (e.g. `tail flicking' and `growling') indicating multiple physiological mechanisms likely modulate aggression in this species. Finally, deslorelin temporarily suppressed hormone concentrations and reproductive function, while clomipramine had no clear effect on either. Ultimately, this information provides important tools for improving male-female pairing success and the overall management of captive clouded leopards.