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Impact Of An Acute Heat Shock During In Vitro Maturation On Interleukin 6 And Its Associated Receptor Component Transcripts In Bovine Cumulus-Oocyte Complexes, Julia Rowinski

Masters Theses

An acute heat stress event after LH surge increased intrafollicular interleukin 6 (IL6) levels in cows that became hyperthermic. To examine direct consequences of the physiologically-relevant elevated temperature of 41.0ºC on the cumulus-oocyte complex (COC), IL6 transcript abundance and related receptor components were evaluated throughout in vitro maturation. Because IL6 and LIF share a signal transducer, LIF was also examined. Abundance of IL6 was interactively influenced by temperature and time (P < 0.0001). Heat-induced increases in IL6 were first noted at 4 hIVM; peak levels occurred at 4.67 versus 6.44 hIVM for 41.0 and 38.5ºC COCs, respectively (SEM = 0.23; P < 0.001). Abundance of IL6R (P = 0.05) and IL6ST (P = 0.002) were also interactively influenced by temperature and hIVM. Peak IL6ST levels occurred at 6.95 versus 8.29hIVM for 41.0 and 38.5ºC, respectively (SEM = 0.23; P < 0.01). Transcript for LIF differed over time (P < 0.0001) but was not affected by 41.0ºC exposure. Blastocyst development after performing IVF was not affected by 41.0ºC exposure for 4 or 6 h. Progesterone released into maturation medium by COCs was interactively influenced by temperature and hIVM (P = 0.0116). When limiting analysis to when IL6 was temporally produced, progesterone levels were only impacted by time and temperature. Heat-induced shift in the temporal production of IL6 along with its impact on progesterone likely cooperate in heat-induced hastening of meiotic progression described by others.

Nutritional Strategies To Improve Utilization Of Nutrients In Lactating Dairy Cows Exposed To Heat Stress, Jeffrey Kaufman

Doctoral Dissertations

Two experiments were conducted to evaluate levels of dietary crude protein (CP) and a new postbiotic prototype from fungal fermentation on nutrient utilization in heat-stressed cows. Experiment 1 consisted of feeding a medium (16.1%) and low (12.5%) CP level to mid-lactating cows in heat stress with or without cooling to assess the interaction. Cooling decreased afternoon body temperature and respiration rates and increased yields of milk, lactose, and protein. Cooling tended to decrease the acute phase reaction in plasma. Compared with low CP, medium CP increased milk fat yield and tended to increased energy-corrected milk yield in cooled cows but …

Effect Of Varying Rumen Degradable And Undegradable Protein On Milk Production And Nitrogen Efficiency In Lactating Dairy Cows Under Summer Conditions, Jeffrey D. Kaufman

Masters Theses

The objective is to determine the effect of reducing nitrogen input through feeding low rumen degradable protein (RDP) and rumen undegradable protein (RUP) proportions on milk production, nitrogen efficiency and metabolism in heat-stressed cows. Forty-eight mid-lactating, Holstein cows were assigned to treatments using a randomized block design in a 2x2 factorial arrangement of treatments (n = 12/treatment). Treatments included two levels of RDP (10 and 8%) and two levels of RUP (8 and 6%). From d 1 to 21, a common diet (10% RDP-8% RUP) was fed to cows followed with their respective treatment diets fed from d 22 to …

The Effect Of Heat Stress And Essential Amino Acids On Production And Metabolism Of Lactating Dairy Cattle, Kimberly Rose Kassube

Masters Theses

Heat stress (HS) causes decreases in production of lactating cattle that is only partially explained by decreases in intake. Evidence suggests that changes in energy and protein metabolism occur to cope with the impact of HS. The objective of this thesis was to determine if the effect of jugular infusion of essential amino acids (AA) ameliorated the negative effects of HS in milk production and metabolism. Twelve multiparous lactating Holstein cows were used in a crossover design to evaluate the effect of thermoneutral (THN) and HS environments along with the absence (CTL) …

Impact Of Matrix Metallopeptidase-9 Supplementation During In Vitro Maturation Of Bovine Oocytes, Megan Rene Goodwin

Masters Theses

Heat-induced decreases in bovine blastocyst development have been related to reductions in latent matrix metallopeptidase-9 (proMMP9) production from maturing cumulus-oocyte complexes. Elevated intrafollicular proMMP9 levels at the time of oocyte retrieval have been positively related to pregnancy following human IVF. Thus, we hypothesized that heat-induced reductions in proMMP9 levels during oocyte maturation may be responsible for decreased blastocyst development. As a first step towards testing this hypothesis, bovine cumulus-oocyte complexes were matured at 38.5°C for 24 h with 0 or 300 ng/mL recombinant human proMMP9 (rhMMP9) added at 0 h of in vitro maturation (hIVM). No differences were found in …

Effect Of Choline Or Betaine Supplementation On Broilers Exposed To Different Temperature Treatments, Joseph D. Summers

Masters Theses

In this study, we looked at the effects of supplemental choline or betaine on broiler performance under different temperature conditions. In total there were eighty pens containing ten birds each for a total of 800 Cobb MX™ X Cobb 500™ (Cobb-Vantress, Incorporated, Siloam Springs, AR, USA). Each pen was randomly assigned to one of five dietary treatments in this study: Treatment 1, basal diet, Treatment 2, basal diet plus 500 methyl equivalents added choline, Treatment 3, basal diet plus 1000 methyl equivalents added choline, Treatment 4, basal diet plus 500 methyl equivalents added betaine, and Treatment 5 basal diet plus …

Effects Of Environmental Enrichment Strategies On Behavior And Production Performance Of Broiler Breeder Chickens Reared At Elevated Temperatures, Oluwatoyin Bukunmi Adeniji

Masters Theses

Enriched housing systems are embraced as better alternatives to bare housing systems for table egg laying hens. However, attention is presently turning to the meat type (broiler breeder) laying hens. Hence, this experiment investigated the effects of perch structures and sharp sand on behavior, physiology, and production performance of broiler breeder chickens reared under elevated temperatures.

Two hundred and eighty eight broiler breeder females and 48 males (Cobb 500) at 21-weeks-old were assigned to their respective treatments in two different rooms. One room was maintained at 23°C to mimic a thermoneutral environment while the second room cycled between 23°C and …

Assessing Mitochondrial Activity In Embryos From Heat-Stressed Ova, Kimberly Ann Nagle

Masters Theses

Elevated ambient temperatures negatively impacts pregnancy rates in agriculturally important females. An oocyte undergoing meiotic maturation exposed to a physiologically-relevant heat stress results in alterations of developmentally important processes and reportedly decreases subsequent developmental potential after fertilization. To address problems of reduced competence after exposure to heat stress for the first 12 h of meiotic maturation (hIVM), Payton (2009) assessed the transcriptome profiles of oocytes and associated cumulus cells by microarray analysis and reported heat-induced perturbations at the molecular level in the oocyte. Specifically, 20 transcripts involved in mitochondrial function exhibited alterations in relative abundance of heat-stressed oocytes …

Stress Effects On Myosin Mutant Root Length In Arabidopsis Thaliana, Brett A. George

Chancellor’s Honors Program Projects

No abstract provided.

The Challenges Of Making A Blastocyst-Stage Embryo: Impact Of Heat Stress & Technical Factors Associated With Ivp Procedures, Estanislao Peixoto

Masters Theses

It was hypothesized that technical factors associated with in vitro production (IVP) of embryos may influence rate of blastocyst development of oocytes matured at 38.5 or 41.0 C. To test this hypothesis, a retrospective meta-analysis was performed. Simple linear regression was performed to analyze continuous variables and ANOVA for categorical variables. Interactions among factors and maturation temperature on blastocyst development were analyzed using dummy regression for continuous variables, and using a factorial treatment design and ANOVA for categorical variables. Month of collection was the only variable that impacted responsiveness of ova to heat stress. Independent of maturation temperature, variables that …

Effect Of Double Interspiking On Fertility, Behavior, And Blood Parameters In Broiler Breeder Males Reared Under Heat Stress Conditions, Karianne Mei-Ying Chung

Masters Theses

Broiler breeders experience a natural decline in fertility levels as a flock ages. A male management practice such as double interspiking could be applied to counteract this decline. Our objective was to investigate the effects of double interspiking on flock fertility, testosterone concentrations, stress responses, and behavioral responses of broiler breeders in heat stressed environments. Two hundred and eighty-eight broiler breeder pullets and thirty-six broiler breeder roosters (Ross 708) were assigned to three groups at 21 weeks of age (WOA). All three groups were housed in slatted floor pens in which room temperature cycled from 23.8 to 30 C to …

Broiler Performance And Mineral Utilization Of Enzyme-Supplemented Defatted Rice Bran Diet During Heat Stress, Ornprapun Puminn

Doctoral Dissertations

Defatted rice bran is a by-product from the solvent-extraction of rice bran. It contains high amounts of phytate and non-starch polysaccharides, which are considered to be two major antinutritional factors that limit the use of rice bran in poultry diets. Two experiments were conducted to evaluate broiler performance and mineral utilization of defatted rice bran diets supplemented with commercial enzyme phytase alone or a combination of phytase and xylanase under two different environmental temperatures. In the first experiment, six replicate groups of day-old chicks were assigned to five dietary treatments comprised of a control corn-soybean meal diet with 25% corn …