Background: Preterm birth is one of the leading causes of perinatal mortality and morbidity and poses extensive economic liability. The rate of preterm births globally is approximately 11.1%, and in the US, the preterm birth rate has been estimated to be 12-13%. Folate and B12 requirements increase during pregnancy as a result of increased cell division to accommodate maternal and fetal growth; inadequate levels can result in placental abnormalities and thus present implications for preterm birth. Objective: To investigate the association between red blood cell (RBC) folate and B12 concentrations with the risk of preterm birth. Methods: Study participants were recruited from Tampa General Hospital between January 2011 and May 2013. Women with a singleton delivery occurring less than 37 weeks gestation were classified as cases and those with a singleton delivery occurring between 37 and 42 weeks gestation were classified as controls. The study had a final sample size of 227 women, including 36 cases and 191 controls. Maternal blood was collected in order to measure folate and B12 concentrations. The association between folate/B12 and preterm birth was assessed using logistic regression; odds ratio (OR), 95% confidence interval (CI) and p values are reported. A power analysis was also performed using the available sample as well as imputation for missing values in the B12 variable. Results: Although not statistically significant, the mean concentration of folate and B12 levels were higher in the cases than in the controls, 894 ± 158.1 vs. 869.2 ± 169.6 and 245.2 ± 102.2 vs 238.3 ± 81.5, respectively. No significant associations were found between folate or B12 and the risk of preterm birth. Conclusions: This study did not detect a significant association between folate or B12 and preterm birth; however, due to the small sample size this analysis was underpowered. Additional studies are needed, preferably using a randomized control study design, in order to elucidate the relationship between folate/B12 and preterm births.

Master of Science / Department of Animal Sciences and Industry / K C Olson / Prepartum fat supplementation has been associated with improved reproductive performance by cows managed for AI. Our objective was to evaluate the effects of prepartum supplementation with whole cottonseed or whole raw soybeans on response to ovulation synchronization and timed artificial insemination in mature beef cows. Cows (n = 188; average initial BW = 579 [plus or minus] 54 kg) were stratified by BCS and BW and assigned to 3 supplementation treatments: whole raw soybeans (21.6 % fat, 38.6% CP), whole fuzzy cottonseed (21.7% fat, 21.1% CP), or a 50:50 mixture of ground corn and soybean meal (2.6% fat, 30.6% CP). Supplements were fed at 1.8 kg per animal daily for 45 d before the first projected calving date (April 1). Supplementation was continued until each cow calved; thereafter, all cows received the control supplement until May 1. Ovulation was synchronized using the CoSynch + CIDR protocol and cows were bred via AI on June 21. Eleven d after AI, cows were exposed for natural service breeding for 50 d. Conception to AI was assessed 33 d after AI. Overall conception was assessed and conception to AI reaffirmed 126 d after AI. Body weight of cows fed control or oilseed supplements was similar (P > 0.3) at calving, initiation of ovulation synchronization, and at the end of the breeding season. Cottonseed-supplemented cows lost more BW and more BCS (P < 0.03) from the beginning of the trial to calving than those fed soybeans. Proportion of cycling cows was similar (P = 0.57) between treatments. Pregnancy to timed AI and final pregnancy rates were similar (P > 0.75) between control and oilseed-supplemented cows. Conversely, supplementation with cottonseed was associated with increased AI conception (P = 0.08; 54 and 39%, for cottonseed and soybeans, respectively) and greater final pregnancy rate compared to soybean-fed cows (P = 0.03; 100 and 93% for cottonseed and soybeans, respectively). Calf birth weights and calf weights at the end of the breeding season were similar (P > 0.24) between treatments. Effects of cottonseed and soybean supplementation on response to ovulation synchronization and timed AI by beef cows warrant further study.

A study was conducted during the period May to September, 1999 to determine the effect of phosphorus (P) supplementation to beef weaners grazing kikuyu (Pennisetum clandestinum) foggage during winter followed by hay towards the end of winter at Dundee in northern KwaZulu-Natal. Foggaging is defined as the practice of allowing herbage to accumulate on a pasture during the growing season (Gertenbach, 1998). This accumulated herbage is then utilized by grazing animals during the dormant season. A total of 200 crossbred beef weaners (average age six months and average weight 175 kg) was used in the trial. Animals were randomly allocated into five groups, each receiving a different supplemental treatment. The treatments were different levels of P supplementation, administered through free-choice P lick supplements, viz. at levels of 0 g P, 2 g P, 4 g P, 6 g P and 8 g P per animal per day. The experiment was divided into two phases. During the first phase (08-06-99 to 20-07-99) the weaners grazed kikuyu foggage and during the second phase (05-08-99 to 16-09-99) they received Smutsfinger(Digitaria eriantha) hay ad libitum. During phase 1 the average weight gain of the animals in Group 1 (receiving 8 g P/animal/day) was significant higher (6 kg/animal during trial) than that of the control group, which received 0 g P/day/animal. Phase 2 which represented a transition from winter to summer showed that Group 1 had an average weight loss of 0.88 kg/animal but the control group lost an average of 5.13 kg/animal. Throughout the trial blood was collected from five animals randomly selected from each group. Plasma inorganic P (Pi) concentrations remained between 1.94 and 2.58 mmol/L. The average trend during phase 1 was that the Pi concentrations increased, while during phase 2, Pi concentrations dropped more (P ¡Ü 0.5) in the animals of Group 1 (8 g P/animal/day) than in the control. This resulted that during the entire experimental period plasma Pi in Group 5 increased while that in Group 1 decreased. Before the animals entered a grazing strip, herbage samples were collected at 14 to 20 day intervals from the five strip grazed kikuyu camps. Samples were divided into leaves and stems which were analysed separately. Mean foggage calcium (Ca) and P concentrations ranged from 25.0 to 29.0 g/kg DM and 20.0 to 27.0 g/kg DM, respectively, while the Ca:P ratios ranged from 1.20:1 to 1.60:1. Calcium concentrations were significantly lower (P = 0.0026) in the stems than in the leaves of the kikuyu foggage, while P concentrations decreased significantly over time, resulting in extremely low foggage P concentrations towards the end of the grazing season. This decrease in P concentrations resulted in Ca:P ratios of above 1:1 instead of the reported ratios of below 1:1 in kikuyu herbage due to low herbage Ca concentrations. The Ca concentrations in the kikuyu in this study were in the same range as herbage concentrations reported in the literature, but P concentrations were much lower than the reported herbage P concentrations. As with the summer pastures we found that magnesium (Mg) concentrations (ranging from 2.1 to 2.6 g/kg DM) were adequate in terms of the requirements of most classes of ruminants. However, potassium (K) concentrations (ranging from 11.4 to 20.3 g/kg DM) were well in excess of animal requirements, and Mg absorption could be severely inhibited by the oversupply of K The sodium (Na) concentration in kikuyu foggage was, as with herbage, inadequate in terms of animal requirements. Zinc (Zn) and manganese (Mn) concentrations were well above animal requirements but below toxic levels. Copper (Cu) concentrations was above animal requirements during May (onset of the study) but decreased significantly to levels below minimum animal requirements. Selenium (Se) concentrations were found to be largely inadequate in terms of animal requirements. The neutral detergent fibre (NDF) levels in kikuyu foggage tended to increase with maturity while acid detergent fibre (ADF) levels did not vary significantly. Crude protein (CP) concentrations decreased as winter progressed to reach levels of < 60 g/kg DM in the dry foggage, indicating that supplementation of CP would be required by animals grazing the kikuyu foggage in mid-winter. It is concluded that if little or no gain is expected from weaners in winter, the Ca and P concentrations in the kikuyu foggage should be adequate. However, if even slight weight gains are required, supplementation of Ca and P would be necessary when the foggage is dry. The P and CP composition of pastures in general were closely correlated and had a seasonal pattern with maximum levels during summer and minimum levels during winter. We can therefore expect that pastures and kikuyu foggage low on protein will also have a P deficiency. In the dry winter we should therefore firstly supplement for protein and energy and then P. The supplementation of P during winter has not only been very positive (in other studies) with positive results on weight gain during the winter period but also during the months thereafter. It is concluded that beef weaners grazing kikuyu foggage in northern KwaZulu-Natal would require supplemental P to maintain their body weights during winter as well as beef weaners on Smutsfinger hay. The recommended level of P supplementation is 8 g P/animal/day. / Dissertation (MSc (Animal Science))--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted

The last 50 years was characterized by a dramatic decrease in free-roaming cheetah populations and consequently the cheetah now appears on the IUCN Red List for Threatened Species. In order to save cheetahs from extinction, a number of projects were launched to breed cheetahs in captivity. Captive cheetahs, however, receive fundamentally different diets than their free-roaming counterparts, which necessitates feed supplementation to fulfill their unique dietary needs. The Hoedspruit Endangered Species Centre (HESC) is one such project aiming to breed captive cheetahs. At the HESC, a number of juvenile cubs were diagnosed with a form of relaxed carpal joints, namely metacarpal deformity of the front legs. Literature suggests that the condition is due to a magnesium deficiency, which is a consequence of an unbalanced diet. Supplementing magnesium to the diet of cheetahs can, however, affect the urinary system negatively: such as the formation of urolithiasis. V The aim of this study was to determine whether dietary magnesium supplementation in the diets of captive cheetahs will remedy metacarpal deformity and also to investigate the influence of magnesium supplementation on the formation of urolithiasis. The study was divided into two phases. Phase 1 was conducted to determine the influence of dietary magnesium supplementation on metacarpal deformity, identified in juvenile cheetahs at the HESC. To determine the degree of deformity, a leg deformity scoring system was developed. On a scale from 1-3, the cheetahs were scored twice to determine the Flexed Deformity Score (FDS) and Rotational Deformity Score (RDS) values before and after dietary magnesium supplementation. Phase 2 was conducted to determine the influence of magnesium supplementation on different physiological parameters that have an influence on the formation of urolithiasis. Phase 2 was divided into three periods. During each period, the cheetahs received a different diet. During period C, the experimental period, the cheetahs were divided into two groups. One group received a meat-only diet, whereas the other group received a meat-Mg diet. At the end of each of the three periods, blood- and urine samples were collected and analyzed to determine the concentration of minerals in the cheetah’s blood plasma and urine. Based on the FDS and RDS scores, a 25.5% response rate to dietary magnesium supplementation on rotational deformities was found, whereas a 60.8% response rate on flexural deformation was found. It is thus concluded that dietary supplementation of magnesium in juvenile cheetahs that experience metacarpal deformities, will remedy the deformity. By analyzing the changes of different blood- and urine parameters in the cheetahs it was observed that dietary magnesium supplementation do influence the formation of urolithiasis. The physiological state of the cheetahs can influence these parameters. The results obtained from the study can be utilized by nutritionists, veterinarians and institutions to enhance the health of captive cheetahs. Copyright / Dissertation (MSc(Agric))--University of Pretoria, 2012. / Animal and Wildlife Sciences / unrestricted

Orientador: Ricardo de Oliveira Orsi / Resumo: A alimentação larval exerce papel fundamental na diferenciação das castas em abelhas Apis mellifera, uma vez que promove a mudança no perfil hormonal e manutenção da integridade do ovário de futuras rainhas. Essa diferença no desenvolvimento é atribuída a sua dieta exclusiva de geleia real, produzida pelas abelhas operárias nutrizes a partir das secreções das glândulas mandibulares e hipofaringeanas. Para essas abelhas, a quantidade e qualidade do pólen consumido são imprescindíveis ao desenvolvimento de suas glândulas, estando diretamente relacionados ao alimento consumido e nutrientes como proteínas, vitaminas e minerais. Dentro deste contexto, minerais como o ferro (Fe) são importantes para o funcionamento celular normal e podem interferir na função da glândula mandibular (produção de geleia real). Neste projeto propomos avaliar o efeito de suplementação de fonte inorgânica de Ferro na alimentação de abelhas e seus reflexos na morfologia da glândula mandibular. Para isto, foram utilizadas 12 colmeias (03 colmeias por tratamento) distribuídas de forma aleatória nos seguintes tratamentos: Fe0 (sem suplementação de Fe); Fe25 com suplementação de 25 mg L-1 de Ferro; Fe50 com suplementação de 50 mg L-1 de Ferro e Fe100 com suplementação de 100 mg L-1 de Ferro. A fonte de ferro utilizada foi o Sulfato Ferroso heptahidratado (33,10% Fe) diluído em xarope de açúcar (proporção de 1:1 de água e açúcar cristal), e fornecido a cada 07 dias para os enxames (500 mL). Para a morfometria ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Larval feeding plays a fundamental role on caste differentiation in Apis mellifera honeybee, since it promotes hormone profile changes and ovary integrity maintenance for future queens. This difference on the development is attributed to its exclusive royal jelly diet, produced by nurse bees into mandibular and hypopharyngeal glands. To these bees, the quantity and quality of pollen consumed is directly related to glands development, linked to nutrients such as proteins, vitamins and minerals from food consumption. In this context, minerals such as Iron (Fe) are important to the normal cell functioning and can affect mandibular glands (production of royal jelly). In this project we propose to evaluate the effects of inorganic Iron supplementation and their effects on mandibular gland morphology. For this, 12 beehives were used (03 hives each treatment) randomly distributed into four treatments: Fe0 (without iron supplementation); Fe25 supplemented with 25 mg L-1 Iron; Fe50 supplemented with 50 mg L-1 Iron and Fe100 supplemented with 100 mg L-1 Iron. Was used Ferrous Sulfate heptahydrate (33.10% Fe) as Iron source, diluted in sugar syrup (1:1 water and sugar), the colonies were feed once a week (500 mL). For glands morphology analysis were collected 20 worker bees from each treatment with six days life along three months: June, July and August 2016. Resin blocks were processed, slices were arranged in slides for analysis using image analyses software Leica Qwin Plus®. Results ... (Complete abstract click electronic access below) / Mestre

Estudos realizados com zigotos bovinos submetidos a uma diminuição de cerca de 50% do conteúdo mitocondrial não apresentaram efeito deletério ao desenvolvimento embrionário in vitro. Este modelo foi desenvolvido pela centrifugação de zigotos após a fecundação in vitro (FIV), retirada do extrato citoplasmático rico em mitocôndrias (ECRM) e posterior introdução de 20-30% de ooplasto (FERREIRA, 2006). Sabendo-se que esse modelo biológico permite o desenvolvimento embrionário em condição de depleção mitocondrial, o objetivo deste trabalho foi avaliar o efeito da remoção e da suplementação mitocondrial em estádio de zigoto visando compreender a importância da organela no processo de desenvolvimento e morte celular programada (MCP). Este trabalho descreve a transferência de mitocôndrias entre zigotos bovinos. Para tanto, foi desenvolvido um sistema de reconstrução de embriões bovinos capaz de gerar indivíduos depletados e suplementados de mitocôndrias. O extrato citoplasmático rico em mitocôndrias (ECRM) dos zigotos centrifugados foi retirado do oócito doador, para gerar um zigoto depletado (D). Posteriormente, foi retirado um volume citoplasmático de aproximadamente 7,1% para gerar um embrião receptor. Com a quantidade retirada do zigoto depletado (doadores), foi realizada a suplementação de zigotos biopsados (receptores), formando assim, o grupo suplementado (S). A depleção mitocondrial causou uma diminuição na quantidade de DNAmt que foi recuperada antes das 72 horas de cultivo possivelmente, devido a um aumento na expressão de mtTFA. Os genes anti-apoptóticos BCL2 e PI3K tiveram sua expressão aumentada nos embriões depletados. A suplementação e depleção mitocondrial resultaram em uma diminuição na taxa de desenvolvimento embrionário até o estádio de 8 células e na formação de blastocistos. A técnica suplementação mitocondrial por meio de micromanipulação não apresentou efeito sobre a quantidade de DNAmt e atividade mitocondrial estimada pelo potencial de membrana interna mitocondrial (&Psi;mm), apresentando um aumento no &Psi;mm apenas às 168 horas em conseqüência do aumento da expressão de COXI e mtTFA. A suplementação e a depleção geraram efeitos negativos na quantidade de núcleos totais e os embriões suplementados apresentaram uma maior taxa de fragmentação de núcleos provavelmente, por um desbalanço de fatores pró e anti-apoptóticos. / Studies developed with bovine zygotes submitted to a decrease of about 50% of the mitochondrial content did not present a deleterious effect on in vitro embryonic development. This model was developed by the centrifugation of zygotes after in vitro fertilization (IVF), removal of the mitochondria enriched cytoplast fraction (MECF) and posterior introduction of 20-30% ooplast (FERREIRA, 2006). Knowing that this biological model allows the development of embryos with mitochondrial depletion, the objective of this study was to evaluate the effect of the mitochondrial removal and supplementation in zygotes aiming to understand the organelle importance in the development and programmed cellular death process (PCD). Therefore, we developed a reconstruction model capable to generate mitochondrial depleted and supplemented embryos. The MECF of the centrifuged zygotes was removed from the donor\'s oocyte (depleted group-D). To prepare the supplemented group (S), a biopsy of approximately 7.1% of the cytoplasm was removed from the recipient zygote for the supplementation with MECF derived from the donor. Mitochondrial depletion caused a decrease of DNAmt amount that was replenished before 72 hours possibly due to an increase of mtTFA, BCL2 and PI3K expression and no effects in &Psi;mm. The technique of mitochondrial supplementation by micromanipulation showed no effect on the mitochondria DNA amount and activity estimated by mitochondrial membrane potential (&Psi;mm). The &Psi;mm increased at 168ha in consequence of an increase in COXI and mtTFA expression. Mitochondrial depletion and supplementation caused a decrease in embryonic development in the 8-cells stage, on blastocyst production and total cell number. The supplementation resulted in increased rates of fragmented nuclei possibly due to an imbalance between pro- and anti-apoptotic factors.

Submitted by Adriana Martinez (amartinez@unoeste.br) on 2017-08-15T19:37:52Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Eloisa.pdf: 351801 bytes, checksum: 5d8bb006aa699c1f75f27ffc6a85479b (MD5) / Made available in DSpace on 2017-08-15T19:37:52Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Eloisa.pdf: 351801 bytes, checksum: 5d8bb006aa699c1f75f27ffc6a85479b (MD5) Previous issue date: 2017-05-23 / L-arginine has been used as a dietary supplement to minimize the side effects of chemotherapy, but it is not fully elucidated its actions and nor the ideal dose that can minimize the side effects. The objective of this study was to evaluate the effect of L-arginine supplementation on the formation of micronuclei in 70 Wistar rats after chemotherapy with 5-FU divided into 7 batches (10 male rats weighing 200 g/batch): LC water ad libitum; LArg2% and LArg4% mice fed commercial feed and 2% and 4% of L-arginine in water ad libitum, respectively; LC rats fed commercial feed, water ad libitum and a dose of 50 mg cyclophosphamide/kg; L5-FU rats fed commercial feed, water ad libitum and a dose of 200 mg of 5-FU/kg was applied; LArg2%+5-FU and LArg4%+5-FU rats fed commercial feed, 2% and 4% L-arginine were added in water ad libitum, respectively, and a dose of 200 mg of 5-FU/Kg. The mice were sacrificed 72 hours after the application of the chemotherapeutics to evaluate the formation of micronuclei. In the data analysis, one-way ANOVA was applied and followed by the Tukey test at 5%. Mice supplemented ad libitum with 2% and 4% L-arginine showed a reduction (P < 0.05) in the formation of micronuclei in bone marrow cells after chemotherapy, indicating that these supplements minimize the mutagenic effect of 5-FU. / A suplementação com L-arginina tem sido utilizada para minimizar os efeitos colaterais da quimioterapia, no entanto, ainda não está totalmente elucidado seus benefícios e nem determinado uma dose ideal de suplementação que pode minimizar esses efeitos. Objetivou avaliar o efeito da suplementação com L-arginina na formação de micronúcleos em 70 ratos Wistar após a aplicação da 5-FU. Estes ratos foram divididos em sete lotes (10 ratos/lote): Lc ratos alimentados com ração comercial e água ad libitum; LArg2% e LArg4% ratos alimentados com ração comercial e adicionou-se 2% e 4% de L-arginina na água ad libitum, respectivamente; Lciclo ratos alimentados com ração comercial, água ad libitum e aplicou-se uma dose de 50 mg de ciclofosfamida/Kg; L5-FU ratos alimentados com ração comercial, água ad libitum e aplicou-se uma dose de 200 mg de 5-FU/Kg; LArg2%+5-FU e LArg4%+5-FU ratos alimentados com ração comercial, adicionou-se 2% e 4% de L-arginina na água ad libitum, respectivamente, e aplicou-se uma dose de 200 mg de 5-FU/Kg. A contagem de micronúcleos nos eritrócitos policromáticos dos ratos foi realizada 72 horas após a aplicação dos quimioterápicos. Os resultados obtidos foram analisados pela ANOVA one-way seguido do teste de Tukey a 5%. Os ratos dos lotes LArg2%+5-FU e LArg4%+5-FU apresentaram redução (P < 0,05) na formação de micronúcleos nos eritrócitos policromáticos após a quimioterapia, indicando que estas suplementações com L-arginina minimizou o efeito mutagênico da 5-FU.

Entre os efeitos ergogênicos levantados pela literatura da creatina estão, aumento de massa muscular, capacidade antioxidante, efeito de tamponamento e redução da lesão muscular ocasionada por exercícios físicos. Visto que a suplementação de creatina pode atenuar danos induzidos pelo exercício físico e influenciar diretamente o sistema ATP-CP, predominante da modalidade de voleibol, o presente estudo propôs o uso da suplementação de creatina associada ao carboidrato durante sete dias, concomitante à realização de um protocolo de indução de dano muscular a fim de investigar a capacidade de manter a integridade da célula muscular por meio de marcadores de lesão muscular e avaliar sua influência no teste de desempenho físico. Foi realizado um estudo duplo cego, randomizado com 14 atletas de voleibol, no qual foi suplementado creatina ou placebo por um período de 7 dias (fase de carga) e 4 dias (fase de manutenção). Antes e após as fases de suplementação os atletas foram submetidos ao teste de desempenho físico e a coleta de sangue para avaliar concentrações de creatina quinase, creatina plasmática e lactato desidrogenase. Após a realização do protocolo de suplementação de creatina foi observado um aumento na concentração total de creatina plasmática, peso corporal e menor percepção de dor no grupo suplementado com creatina. Não foi encontrada diferença no desempenho de salto, potência relativa e marcadores bioquímicos de lesão muscular de ambos os grupos. Quanto a ingestão alimentar, foi observado um aumento no consumo de proteínas e gorduras. Concluiu-se que a suplementação de creatina associada ao carboidrato foi capaz de atenuar a percepção de dor em atletas de voleibol após protocolo de indução de lesão. / Among the ergogenic effects raised by the literature of creatine are, increased muscle mass, antioxidant capacity, buffering effect and reduction of muscle injury caused by physical exercise. Since creatine supplementation may attenuate exercise-induced damage and directly influence the predominant volleyball ATP-CP system, the present study proposed the use of carbohydrate-associated creatine supplementation for seven days, concomitant with the performance of one muscle damage induction protocol to investigate the ability of creatine to maintain muscle cell integrity through muscle injury markers and to assess their influence on the physical performance test. A double-blind, randomized study with 14 volleyball athletes was performed with the supplementation of creatine or placebo for a period of 7 days (loading phase) and 4 days (maintenance phase). Before and after the supplementation phases, athletes underwent physical performance test and blood collection to evaluate concentrations of creatine kinase, plasma creatine and lactate dehydrogenase. After the creatine supplementation protocol an increase in plasma creatine total concentration, body weight and lower perception of pain in the creatine group was observed. No difference was found in the jump performance test, relative power and biochemical markers of muscle injury in both groups. Regarding food intake, there was observed an increase in protein and fat intake. In concluson, carbohydrate-associated creatine supplementation was able to attenuate the perception of pain in volleyball athletes after injury induction protocol.

Two trials were conducted simultaneously to evaluate the effects of energy supplementation for cattle grazing tropical pastures managed with different initial sward heights on DMI and ruminal fermentation of cattle grazing intensively managed tropical grass during the rainy season. Eight 24-month-old rumen-cannulated Nellore steers were used per trial (Trial 1: 300 kg BW ± 5.97, Trial 2: 343 kg BW ± 7.40) allocated in two 4x4 Latin squares. Treatments corresponded to 0 (mineral supplementation) and a 0.3 (0.3% of BW of ground corn as fed basis) combined with 2 pre-grazing sward heights (25 and 35 cm). The stubble height was 15 cm. In the second trial the level of supplementation was 0.6% BW of ground corn as fed basis. Steers were managed in 2 ha of Palisadegrass pasture (Brachiaria brizantha marandu). Pastures were fertilized with 120 kg nitrogen/ha and averaged 13.8 and 11.0% CP and 58.8 and 63.4% NDF, for 25 and 35 cm, respectively The forage and the diet DM and CP digestibility were greater (P<0.05) for 25 then for 35 cm grazing management. For both trials 1 and 2, cattle grazing the pastures with 25 cm initial sward height consumed more forage DMI, more total DMI and more energy (P<0.05) and at the same time steers spent less time grazing (P<0.05) and more time resting (P<0.05), presented greater bite rates (P<0.05), less steps per day and less steps between feeding stations (P<0.05), when compared with cattle grazing the 35 cm pastures. Rumen pH values were less (P<0.05 in trial 1; P<0.1 in trial 2) and concentrations of rumen N-NH3 and retention of N were greater (P<0.05) for cattle grazing the 25 cm pastures while rumen VFA and microbial synthesis were not affected (P>0.05) by pasture management. Supplementing energy at 0.3% (trial 1) increased (P<0.05) diet DM digestibility while feeding energy at 0.6% (trial 2) decreased forage CP digestibility, increased (P<0.05) forage NDF digestibility and increased diet DM (P<0.05) and diet NDF (P<0.1) digestibility. Supplementing energy at 0.3% (trial 1) or at 0.6% (trial 2) decreased forage DMI (P<0.05) and substitution rates were 1.63 and 0.72, respectively. The total DMI and energy intake were not increased (P>0.05) by supplementing energy at 0.3% while increasing energy supplementation to 0.6% was effective to increase total DMI and energy intake of cattle grazing tropical forage, independent of initial sward height. Energy supplementation decreased (P<0.05) grazing time, but it did not affect (P>0.05) any other grazing behavior parameter. Supplementing grazing cattle with 0.3% had no effect (P>0.05) on rumen pH, N retention and microbial synthesis, increased (P<0.05) rumen propionate and decreased (P<0.05) rumen N-NH3, rumen acetate and acetate:propionate ratio. Supplementing grazing cattle with 0.6% decreased (P<0.05) rumen pH, rumen N-NH3, rumen acetate and acetate:propionate ratio, while it increased (P<0.05) rumen propionate, N retention and microbial synthesis. Plasma glucose was not affected by treatments (P>0.05). The pre-grazing sward height of 25 cm and feeding energy supplement at 0.6% of BW were efficient strategies to increase energy intake of cattle grazing Palisadegrass. / Dois experimentos foram conduzidos simultaneamente, para avaliar o uso da suplementação energética para bovinos manejados em diferentes alturas de entrada na pastagem. Foram usados 8 novilhos Nelore canulados no rumen por experimento (Exp. 1: 300 kg de PC ± 5,97, Exp. 2: 343 kg PC ± 7,40) distribuídos em 2 quadrados latinos 4x4. Os tratamentos para o Exp. 1 foram 0 (suplementação mineral) e 0,3 (0,3% do PC em milho moído) combinados com 2 alturas de entrada (25 e 35 cm). A altura de saída foi 15 cm. No Exp. 2 o nível de suplementação foi 0,6% do PC em milho moído. Os animais foram manejados em 2 ha de Capim Marandu, os quais foram adubados com 120 kg de N/há, apresentando valores médios de 13,8 e 11,0% de PB e 58,8 e 63,4% de FDN para pastos de 25 and 35 cm, respectivamente. A DMS e DPB da forragem e da dieta foram maiores (P<0,05) para o manejo da pastagem de 25 cm do que 35. Em ambos os experimentos, o CMS de forragem, energia e total foi maior (P<0,05) para o tratamento de 25 cm, que ao mesmo tempo promoveu menor tempo de pastejo (P<0,05), maior tempo em ócio (P<0,05) e taxa de bocado (P<0,05), menor número de passos por dia e passos entre estações de pastejo (P<0,05), quando comparados com animais mantidos no tratamento de 35 cm. O pH ruminal foi menor (P<0,05 no Exp. 1; P<0,10 no Exp. 2), a N-NH3 ruminal e retenção do N foram maiores (P<0,05) para animais manejados na altura de entrada de 25 cm. Os AGVs e a síntese microbiana não foram afetados (P>0,05) pelo manejo da pastagem. A suplementação em 0,3% (Exp. 1) aumentou (P<0,05) a DMS da dieta, enquanto a suplementação de 0,6% (Exp. 2) reduziu a DPB da forragem (P<0,05), aumentou a digestibilidade da FDN da forragem (P<0,05) e a DMS (P<0,05) e da FDN da dieta (P<0,01). A suplementação em 0,3% (Exp. 1) ou em 0,6% (Exp. 2) reduziu o CMS de foragem (P<0,05) e as taxas de substituição foram 1.63 and 0.72, respectivamente. O CMS total e de energia não foram aumentados (P>0,05) pela suplementação em 0,3%, enquanto o nível de 0,6% foi efetivo em aumentar o CMS total e de energia de bovinos mantidos em pastagem tropical, independente do manejo da pastagem. A suplementação reduziu o tempo de pastejo (P<0,05). Animais suplementados com 0,3% não alteraram (P>0,05) o pH ruminal, a retenção de N e síntese microbia, mas aumentaram (P<0,05) propionato no rumen e diminuíram (P<0,05) N-NH3 ruminal, acetato e relação acetato:propionato. A suplementação com 0,6% diminuiu (P<0,05) o pH ruminal, N-NH3 ruminal, acetato e relação acetato:propionato no rumen, aumentaram (P<0,05) o propionato no rumen, a retenção de N e a síntese microbiana. A glicose plasmática não foi alterada (P>0,05). A altura de pré-pastejo de 25 cm e a suplementação energética de 0,6% do PC foram estratégias eficientes para aumentar o consumo de energia de bovinos mantidos em pastagens de Capim Marandu.

A fermentação de mosto com alta concentração de açúcar (ACA) pode ser utilizada em escala industrial para a produção de etanol combustível. Esta tecnologia apresenta vantagens como a obtenção de níveis mais elevados de etanol e a minimização dos custos de produção, em contraposição apontam novos desafios, como minimizar os efeitos do estresse, osmótico e alcoólico, que as leveduras são submetidas. A suplementação do mosto com fontes nitrogenadas pode aumentar o rendimento de etanol durante a fermentação alcoólica, visto que este elemento desempenha importantes funções na fisiologia da levedura. Para avaliar o efeito da suplementação de mosto ACA, caldo de cana-de-açúcar concentrado a 25°, 30° e 35°Brix e suplementado com sulfato de amônio foi fermentado por linhagens comerciais de levedura, PE-2 e CAT-1, a 30ºC e 60rpm e monitorado por ciclos de 24 horas. Seis ciclos fermentativos foram realizados, mediante o reciclo das células de levedura por centrifugação a 2.000 g por 15 min. Os parâmetros analisados foram o desprendimento de CO2 obtido por avaliação da massa (pesagem em balança analítica); viabilidade celular determinada pelo método de coloração com eritrosina; teor alcoólico determinado em densímetro digital, após destilação da amostra, análise de açúcares totais e residuais por cromatografia de troca iônica e a concentração de nitrogênio assimilável determinada colorimetricamente pelo método da ninidrina, utilizando glicina como padrão. A suplementação dos meios com sulfato de amônio propiciou maiores taxas reprodutivas das leveduras, formando maior biomassa em todas as concentrações de Brix estudadas. Os valores de etanol observados foram superiores nas amostras suplementadas, atingindo um teor acima de 16% (v/v) para a linhagem CAT-1 e acima de 15,5% (v/v) para a linhagem PE-2 no mosto contendo 30°Brix. Entre as linhagens, a CAT-1 foi a que suportou melhor a pressão osmótica do meio e, consequentemente, apresentou produtividade fermentativa superior, atingindo uma produção acima de 5,2g/L/h. A presença da fonte de nitrogênio mostrou ser fundamental para o processo fermentativo, principalmente em mosto ACA, com concentrações mais elevadas de açúcar. A fermentação do mosto com 25°Brix não apresentou o mesmo comportamento. / The fermentation of sugar cane wort with a high concentration of sugar (ACA, very high gravity) can be used on an industrial scale for the production of fuel ethanol. This technology has the advantage of achieving higher levels of ethanol and reduction of production costs, although the challenges are to minimize the effects of osmotic and alcohol stress that the yeasts are subjected. Supplementation with nitrogen sources provides important roles in the physiology of yeast and it can increase the yield of ethanol during fermentation. To evaluate the effect of supplementation of ACA wort, juice of sugar cane was concentrated at 25°, 30° and 35°Brix and supplemented with ammonium sulfate. The medium was fermented by commercial yeast strains, PE-2 and CAT-1, at 30° C, with orbital shaking. The process was followed in 24 hours cycles. Six fermentation cycles were performed with the yeast cells recycling. At the end of each cycle, the yeast biomass was separated from liquid fraction by centrifugation at 2,000 g for 15 min. Progress of fermentations was analyzed by measuring CO2 production by evaluating the mass reduction; yeast cell viability by staining method with erythrosine; alcoholic content of distilled sample was determined by densitometry, residual sugars were analyzed by ion exchange chromatography and assimilable nitrogen concentration determined colorimetrically by ninhydrin method, using glycine as standard. The strains PE-2 and CAT-1 with ammonium sulfate reached higher reproductive rates and improved biomass at all sugar concentrations. Higher ethanol production was observed in the supplemented samples, reaching a level above 16% (v/v) for CAT-1 strain and above 15.5% (v/v) for PE-2 strain at 30° Brix concentration. CAT-1 strain showed more tolerance with the high osmotic pressure of the medium and consequently improved productivity fermentation, reaching an ethanol production above 5.2 g/L.h. Nitrogen source proved to play a crucial role in the fermentation process, mainly in ACA wort, however, the same effect was not observed at 25°Brix.