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Sarcopenia is a condition that is most common in aged animals, and is characterized by the loss of skeletal muscle mass and integrity, and can lead to physical disability and poor quality of life. Since skeletal muscle protein synthesis can be limited by the availability of amino acids, supplementation of limiting amino acids to ameliorate the progression of sarcopenia has become a topic of interest in companion animal research. Although there is some data to support the idea that amino acid supplementation improves maintenance of muscle mass in aged horses, the cellular mechanisms behind that improvement have yet to be elucidated. Therefore, the objective of this study was to examine the effect of amino acid supplementation in aged horses on markers of whole body and muscle protein metabolism. In a cross-over design, six old horses were studied while receiving each of three treatments in a replicated Latin square design. For all three treatments, horses received 1.8% BW/d of timothy hay cubes and 0.5% BW/d of experimental concentrate. The three treatments included a control (CON) treatment concentrate that was designed to meet all requirements of mature horses when fed in combination with the timothy hay cubes, and two supplemented concentrates, LYS/THR with additional lysine and threonine (40 mg/kg BW/d and 31 mg/kg BW/d, respectively), and LYS/THR/MET with additional lysine, threonine, and methionine (40 mg/kg BW/d, 31 mg/kg BW/d and 11mg/kg BW/d respectively). In each 15 d period, following a 9-day adaptation, horses were fitted with a collection harness, and total urine and feces were collected for 72 hours for assessment of nitrogen balance and creatinine output. Blood samples were taken directly before feeding and 30, 60, 90, 120, 150, 180, 210, and 240 minutes post-feeding for analysis of plasma urea nitrogen (PUN), glucose, insulin, and plasma amino acid concentrations. Muscle biopsy samples were taken for analysis of proteins in the mTOR pathway. Additionally, horses underwent stable isotope infusion procedures, and comparisons of phenylalanine kinetics were used to determine whole-body rates of protein synthesis and degradation. There was no significant effect of treatment on creatinine output (P=0.58), relative abundance of proteins in the mTOR pathway (P>0.05), nitrogen retention (P=0.70), or phenylalanine kinetics (P>0.05). PUN concentrations were significantly (P=0.0058) higher for LYS/THR and LYS/THR/MET than for CON. Atrogin-1 activation was significantly higher for the pre-feeding CON sample compared to the post-feeding CON sample. Lack of significant difference in creatinine output suggests that there were not significant differences in muscle mass between treatments. Lack of significant differences in mTOR protein activation suggests that amino acid supplementation did not result in improvements in protein synthesis. Lack of significant differences in nitrogen retention and phenylalanine kinetics suggests that whole-body protein metabolism was not improved. Additionally, higher PUN concentrations in the supplemented diets suggests that the supplemented amino acids being provided were catabolized. However, increased activation of Atrogin-1 in the pre-feeding CON samples, but not the pre-feeding samples of supplemented treatments, suggests amino acid supplementation may have reduced protein degradation in the post-absorptive state. Data from the present study suggests that amino acid availability may not have been limiting protein synthesis in the sedentary aged horses in the present study.

The aim of this thesis was to investigate how physiological and environmental factors affect surfing performance. Studies were performed that assessed the effect of anthropometric and physiological characteristics of surfers on rank and ability, the effect of creatine supplementation on surfing performance and the effect of wave size, wave period and the ability of surfers on physiological and performance indices of surfing. Study one investigated the effect of the anthropometric variables on rank and rating of ability. This was measured across a sample of 79 surfers ranging from intermediate to professional surfers. Significant correlations were found for endomorphy (r = -0.366, P <0.01), sum of six skinfolds (r = -0.274, P <0.05), Body fat percentage (r = -0.268, P <0.01) and mesomorphy (r = 0.442, P <0.01). Findings suggest that levels of adiposity and muscularity might influence the potential for progression between intermediate and professional level surfing performance. Study two investigated the effect of physiological variables on the national ranking of 18 elite male junior surfers using assessments of maximal oxygen uptake, lower body explosive power, upper body power, agility, and balance. Partial correlations were used to account for the influence of age within the sample and a significant correlation was found between power output at (rp = -0.879, P <0.01). Findings suggest that power output at is an important factor for achieving competitive success in high performance junior surfers. Study three investigated the effect of short term (20g.day-1 for 5 days) creatine supplementation on body composition, repeated upper body anaerobic power and competition performance was assessed in 17 club level surfers. Testing comprised assessment of body mass and total body water using bioelectrical impedance analysis, a repeated upper body Wingate based on time motion analysis of competitive surfing. A two-way repeated measures ANOVA found no significant effects of supplementation on laboratory measures of anaerobic power or competitive performance. The fourth study investigated the effects of changes in wave conditions on physiological response and performance parameters of surfing. This was assessed using 39 surfers who participated in 60 surfing sessions where wave conditions were recorded and performance was measured using GPS. The study found that wave height was significantly related to energy expenditure (rp =-0.351, P <0.05), maximum ride speed (rp = 0.866, P <0.01), the standard deviation of maximum ride speeds (rp = 0.654, P <0.01), mean ride time (rp = 0.354, P <0.01), maximum ride time (rp = -0.296, P <0.05), the standard deviation of the ride times expenditure (rp = -0.344, P <0.01), mean ride distance (rp = 0.398, P <0.01), maximum ride time (rp = 0.318, P <0.05), minimum ride distance (rp = 0.268, P <0.05), standard deviation of the ride distances (rp = -0.362, P <0.01), percentage of total distance riding (rp = 0.310, P <0.05), percentage of time spent waiting (rp = -0.272, P = 0.05), percentage of total time spent riding (rp = 0.396, P < 0.01), percentage of total time in miscellaneous activities (rp = 0.471, P <0.01), total distance riding (rp = 0.310, P =0.05), total distance per hour (rp = 0.427, P <0.01). Wave period was found to be significantly related to average heart rate as a percentage of maximum (rp = 0.490, P <0.01), the percentage of time spent in the “easy” training zone (rp = -0.408, P <0.01), maximum ride speed (rp = 0.371, P <0.01), mean ride time (rp = 0.283, P <0.05), maximum ride distance (rp = 0.279, P <0.05), and the standard deviation of the ride distances (rp = 0.325, P <0.05). The ability levels of the surfers were found to be significantly related to average heart rate as a percentage of maximum (rp = -0.412, P <0.01), percentage of time in the “steady” zone (rp = 0.435, P <0.01), percentage of time in the “intermittent” zone (rp = 0.483, P <0.01), maximum ride speed (rp = 0.454, P <0.01), mean ride distance (rp = 0.392, P <0.05), standard deviation of the ride distances (rp = 0.264, P <0.05), percentage of the total distance riding(rp = 0.267, P <0.05), percentage of time paddling (rp = 0.364, P <0.05), percentage of time in miscellaneous activities (rp = -0.299, P <0.05), total distance riding (rp = 0.267, P <0.05) and average speed (rp = 0.428, P <0.01). This thesis has found that ability in surfing is related to anthropometric and physiological measures, creatine supplementation improves peak anaerobic power but does not significantly improve surfing performance in club level surfers and that wave conditions and the skill levels of surfers are significantly related to the physiological and performance parameters of surfing.

Four studies were conducted to evaluate the potential for post-extraction algal residue (PEAR) to be incorporated as a protein source in the grazing sector of the beef cattle industry. In Experiment 1, blends of PEAR and conventional protein supplements (dried distillers’ grains, DDG; cottonseed meal, CSM) were offered to steers consuming Bermudagrass to evaluate palatability of PEAR. Supplement completion, time required for consumption, and amount of supplement consumed were recorded. In Experiment 2, isonitrogenous amounts of PEAR and CSM (100 mg N/kg BW) were supplemented to steers consuming low-quality forage to compare effects on nutrient utilization. Experiment 3 evaluated the optimal inclusion rate of PEAR to steers consuming low-quality forage. Treatments included no supplemental protein, 3 levels of PEAR (50, 100, and 150 mg N/kg BW) and 1 level of CSM (100 mg N/kg BW). In Experiment 4, the effects of upstream operations on the nutritive value of PEAR were quantified. Observations indicate PEAR may be blended with existing protein sources in the beef industry without negatively affecting palatability, but there may be palatability concerns when PEAR is offered alone. Provision of 100 mg N/kg BW of PEAR or CSM stimulated forage intake (P ≤ 0.05) and increased N retention (P = 0.02) relative to unsupplemented animals. Imbalances in mineral intakes (Ca:P ratio of 8:1) were observed when PEAR was supplemented, but not CSM. Total digestible OM intake (TDOMI) responded quadratically (P = 0.01) to increasing provision of PEAR with maximization occurring when PEAR was provided at 100 mg N/kg BW. There was not a difference in TDOMI (P = 0.13) at isonitrogenous levels of PEAR and CSM, indicating forage utilization was stimulated to a similar extent. Excess mineral levels and imbalances in PEAR were largely a result of cultivation, harvesting, and extraction procedures which could be controlled. Thus, there is potential to alter production streams to optimize oil yield and co-product value. Overall, our results indicate PEAR can be incorporated as a protein source in the beef cattle industry, thus increasing economic viability of biofuel production from algal biomass.

Alzheimer’s disease (AD), the most common form of dementia in the elderly, is a global issue affecting about 24 million individuals. Because AD is a systemic pathology, dementia is not the only leading factor contributing to loss of independence in AD patients. AD may also impair skeletal muscle metabolism and function. Creatine (CR) supplementation may enhance skeletal muscle hypertrophy/mass and function in sarcopenia and muscular dystrophies, but has yet to be studied in AD. This study examined the effect of oral CR on muscle metabolism in a triple-transgenic (3xTg) AD mouse model. Twenty-four, 3×Tg AD mice (~8 month-old) were randomly assigned to control (CON) or CR (3% w/w) diet. Bodyweights and feed intakes were measured throughout the 8-week study. Lower limb (quadriceps muscle; QM and gastrocnemius; GM) and upper limb muscles (triceps; TM) were collected to analyze levels of CR, total protein, DNA, RNA, amino acids (AA), adenosine triphosphate (ATP), adenosine diphosphate (ADP), total and phosphorylated p70 ribosomal S6 kinase (p70S6K). Data (mean ± SEM) were assessed by analysis of variance (ANOVA) and Fisher’s least significant difference (LSD) post hoc test. In comparison to the CON group, CR supplementation increased CR content in both GM (p=0.002) and QM (p=0.037), with higher (p=0.032) ATP/ADP ratio in CR in comparison with CON in QM. A higher protein concentration (p<0.0001) was notable in GM of CR supplemented group vs. CON. Total branched-chain AA levels in QM increased 2-fold (p< 0.0001) in CR groups. Additionally, CR resulted in a higher (p<0.05) protein/DNA ratio; an index of muscle cell size, in both QM and GM for CR groups. The index of cell capacity for protein synthesis (RNA/DNA ratio) in GM was also higher (p=0.001) in CR groups. However, phosphorylation (activation) level of p70S6K, an integral component in protein synthesis signalling pathway, did not show any significant differences in female (p=0.161) and male (p=0.292) CR supplemented groups compared with CON. To conclude, CR supplementation is capable of inducing muscle hypertrophy/growth parameters in the 3×Tg AD mouse model, thereby enhancing protein synthesis capacity in skeletal muscles, thus possibly promoting muscle function in AD. / May 2016

Master of Science / Department of Animal Science and Industry / Barry Bradford / During the past decades, the dairy industry has been challenged to find alternative approaches in order to feed cows without affecting their performance or increasing production costs. To accomplish these objectives, some options that have been implemented are the inclusion of short chain carbohydrates to replace starch and the addition of synthetic supplements to increase feed efficiency. In order to assess the impact of these strategies, an experiment was conducted to evaluate productive responses of lactating dairy cattle when they received sucrose and/or exogenous amylase in low starch diets. The results indicated that milk production, milk component profile, and feed efficiency were not significantly altered by the use of the enzyme, sucrose inclusion, or the combination of both. Comparing these results with the literature revealed apparent inconsistencies in responses to the inclusion of sugar in dairy rations. For that reason, a meta-analysis was performed to determine the impact of different sugar sources on milk production, and also to evaluate the impact of other dietary factors on response to dietary sugar. The results indicated that dry matter intake responses were significantly (P < 0.05) affected by an interaction between added sugar and dietary forage neutral detergent fiber content, but overall, dry matter intake tended to increase when sugar replaced corn grain in diets. Energy corrected milk was not affected by dietary sugar, but milk production showed a tendency to respond to treatment, dependent on an interaction between added sugar and rumen undegradable protein. In summary, sugar inclusion may promote small increases in dry matter intake, but the impact on milk production is inconsistent; both factors may be influenced by the diet to which sugar is added.

Esse trabalho objetivou estudar os efeitos da suplementação de novilhos Nelore de sobreano no período das águas em pastagem e a posterior terminação em confinamento. O experimento foi conduzido com 40 animais, inicialmente em quatro piquetes de 6,75 ha cada, de Brachiaria brizantha e teve duração de seis meses. Após esse período, os animais foram levados para baias individuais do confinamento, que teve duração variável e terminava quando os animais atingiam o peso de abate (450,00 kg). Para a suplementação em pastagem, os 40 animais foram divididos em 4 grupos de 10 animais (um para cada pasto), sendo que dois grupos receberam suplemento mineral (controle) e dois, suplemento energético (suplementado). Após o período em pastagem, os animais foram terminados em confinamento, com dieta única. A suplementação energética em pastagem propiciou maior ganho em peso dos animais (P< 0,05). No confinamento, os animais que receberam suplementação nas águas atingiram o peso de abate mais cedo, mas os do grupo controle apresentaram os maiores ganhos (P<= 0,05). / This research investigated the effects of yearling Nellore supplementation during the water period of grazing and subsequent feedlot finishing. The experiment was conduced with 40 animals, initially in four paddocks of 6,75 ha each, of Brachiaria brizantha during six months. After this period, the animals were moved to individual stalls in feedlot area, wich had variable duration and ended when the animals reached slaughter weight (450.00 kg). For the supplementation in grazing period, the 40 animals were divided in four groups of 10 animals (one for each paddock), and two groups were fed with mineral supplement (control) and two with energy supplement (supplemented). After the grazing period, the animals were finished in feedlot with only one diet. Energy supplementation in grazing period causes greater weight gain of animals (P< 0,05). In feedlot, animals that were supplemented in water period reached slaughter weight earlier, but the unsupplemented group had the highest weight gain (P<= 0.05).

Os diversos estudos com a suplementação de glutamina em situações de estresse fisiológico demonstram o essencial papel deste aminoácido no metabolismo. Agudamente, a suplementação com glutamina aumenta a glutaminemia. Cronicamente, verifica-se maior concentração de glutamina em tecidos, tais como o muscular e o hepático. Entretanto, não é conhecido se esses efeitos são decorrentes diretos da suplementação oral com glutamina ou da redução de sua captação a partir da membrana basolateral de enterócitos. O estudo da cinética na absorção de glutamina traz informações relacionadas à proporção da concentração de glutamina absorvida e a retida no tecido intestinal, de acordo com as doses utilizadas, e aponta quais são as alterações decorrentes da sepse induzida pela endotoxemia. O objetivo deste trabalho foi investigar a cinética de absorção de glutamina em camundongos submetidos à endotoxemia, o que não fora previamente investigado em outros trabalhos. Para avaliar a cinética da absorção intestinal de glutamina foi realizada eversão intestinal em camundongos machos, o que permite a coleta dos líquidos das camadas mucosa e serosa com maior precisão. Foram utilizadas doses de 10, 20, 40 e 50 mM de L-glutamina associada a [14C]-glutamina, nos tempos 0, 5, 10, 20, 30, 40, 60, 90 e 120 minutos. Os resultados obtidos demonstraram que em alta concentração de glutamina (50 mM) ocorre maior absorção em relação à retenção tecidual e esta é realizada por transporte ativo de aminoácidos. Os animais que foram submetidos à endotoxemia por LPS (5mg/kg) apresentaram alterações estruturais no tecido intestinal, detectadas pela histologia. Neste grupo, a retenção tecidual de glutamina foi significativamente maior do que no grupo controle, sobretudo na presença de glicose. Conclui-se que a cinética na absorção de glutamina é dose e tempo dependente em animais saudáveis e que, em condições de endotoxemia, ocorre maior retenção de glutamina no tecido intestinal na presença de glicose. Sugere-se que a via da hexosamina está envolvida; no entanto, mais estudos são necessários para esclarecer tais mecanismos. / The various studies of glutamine supplementation in stressful situations demonstrate the physiological role of this essential amino acid in metabolism. Acutely, supplementation with glutamine improves glutaminemia. Chronically, there is a greater concentration of glutamine in tissues such as muscle and liver. However, it is not known whether these effects are direct result of glutamine oral supplementation or reduced uptake within the basolateral membrane of enterocytes. The kinetic study of the absorption of glutamine provides information related to the ratio of concentration of glutamine absorbed and retained in the intestinal tissue, according to the doses used, and points out the changes resulting from sepsis induced by endotoxemia. The objective of this study was to investigate the kinetics of glutamine uptake in mice subjected to endotoxemia. To evaluate the kinetics of intestinal absorption of glutamine intestinal eversion was performed in male mice, allowing to collect the liquid layers of mucosa and serosa with greater precision. The doses used were 10, 20, 40 and 50 mM L-glutamine associated with [14C]-glutamine at 0, 5, 10, 20, 30, 40, 60, 90 and 120 minutes. The results showed that high concentrations of glutamine (50 mM) a higher absorption occurs in relation to tissue retention and this is accomplished by active transport of amino acids. The animals subjected to endotoxemia by LPS (5mg/kg) showed structural changes in the intestinal tissue, detected by histology. In this group, the tissue retention of glutamine was significantly higher than in the control group, especially in the presence of glucose. It is concluded that the kinetics of glutamine uptake is dose and time dependent in healthy animals, and in conditions of endotoxemia, there is greater retention of glutamine in intestinal tissue in the presence of glucose. It is suggested that the hexosamine pathway is involved; however, more studies are needed to clarify these mechanisms.

O experimento foi realizado com o objetivo de avaliar o efeito de diferentes regimes de alimentação e de diferentes aditivos na dieta de suínos na fase de terminação. Foram utilizados 144 animais, da linhagem DB os quais foram pesados e distribuídos em delineamento em blocos casualizados, em esquema fatorial 2 x 4 (2 regimes de alimentação: a vontade e restrito; 4 formas de suplementação de aditivos na dieta: sem adição, cromo, ractopamina, cromo + ractopamina), totalizando 8 tratamentos com 6 repetições (3 repetições de machos e 3 repetições de fêmeas) e 3 animais cada, no período de 42 dias. Antes do início do experimento, foi avaliado o consumo médio dos animais para o fornecimento das dietas experimentais, o qual era corrigido semanalmente. Foi realizada uma restrição quantitativa da dieta em 15% em relação ao consumo dos animais alimentados à vontade, sendo que a restrição foi aplicada desde o primeiro dia do experimento e o fornecimento das dietas contendo o cromo e a ractopamina, a partir do 15º dia do experimento, ou seja, nos últimos 28 dias. Entretanto, os níveis nutricionais foram acrescidos em 15% para garantir o consumo da mesma quantidade de nutrientes da dieta. No final do experimento, um animal por repetição foi abatido para determinar a qualidade da carcaça dos animais. Foram avaliados dados de desempenho (ganho de peso, consumo médio e conversão alimentar) e de rendimento de carcaça (espessura de toucinho; espessura de músculo; porcentagem de carne magra). Os tratamentos não apresentaram efeito significativo para o desempenho dos animais sobre o consumo médio diário e o ganho médio de peso. Não houve diferença significativa para as características de carcaça. Os animais com restrição alimentar apresentaram diferença significativa (P&lt;0,001) na conversão alimentar quando comparada com a alimentação à vontade. O uso do cromo e da ractopamina de forma isolada ou em conjunto melhoraram a conversão alimentar em comparação aos animais que receberam a ração controle. / The experiment was carried out with the objective of evaluating the effect of different feeding regimes and different additives in the diet of pigs in the finishing phase. A total of 144 animals of the DB lineage were used, which were weighed and distributed in a randomized block design, in a 2 x 4 factorial scheme (2 feeding regimes: will and restricted, 4 supplementation forms in the diet: Chrome, ractopamine, chromium + ractopamine), totaling 8 treatments with 6 replicates (3 replicates of males and 3 replicates of females) and 3 animals each, in the period of 42 days. Before the beginning of the experiment, the average consumption of the animals for the experimental diet was evaluated, which was corrected weekly. A quantitative restriction of the diet was performed in 15% in relation to the consumption of the animals fed at will. The restriction was applied from the first day of the experiment and the diets containing chromium and ractopamine were applied from the 15th day of the experiment. Experiment, that is, in the last 28 days. However, nutritional levels were increased by 15% to ensure consumption of the same amount of nutrients from the diet. At the end of the experiment, one animal per replicate was slaughtered to determine the quality of the carcass of the animals. Performance data (weight gain, mean intake and feed conversion) and carcass yield (fat thickness, muscle thickness, lean meat percentage) were evaluated. The treatments had no significant effect on the performance of the animals on average daily consumption and average weight gain. There was no significant difference in carcass characteristics. Feed restriction animals showed a significant difference (P &lt;0.001) in feed conversion when compared to feed at will. The use of chromium and ractopamine alone or in combination improved feed conversion compared to animals receiving the control ration.