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The present study evaluated the effect of temporal periods of hypothermia and hyperthermia, followed by an optimal temperature recovery phase on the growth, survival, and physiological response of Penaeus vannamei. Post-larvae were exposed to stress periods for 7 and 14 days at 22 °C and 32 °C each, followed by a recovery phase at 28 °C to complete seven experimental weeks, and were compared with a control group maintained at 28 °C. Weight gain, specific growth rate, feed intake, feed conversion ratio, and survival were weekly determined. Muscle, hepatopancreas, and hemolymph were sampled on the 14th day of the recovery phase for biochemical composition, and antioxidant and digestive enzyme activities determination. The shrimp presented a higher growth rate during short-term hyperthermia in contrast to shrimp under hypothermia that presented compensatory growth after thermal stress when the temperature was restored at 28 °C. Hyperthermia increased 12-13% the feed intake while this was diminished 21-29% by the hypothermia periods. Shrimp undergo metabolic adjustments following thermal stress, with short hypothermia increasing the lipase activity and lipid storage in the hepatopancreas, while short hyperthermia also enhances chymotrypsin activity and leads to higher protein and lipid accumulation. Conversely, prolonged hyperthermia induces greater energy consumption, depleting lipid and glycogen stores, while hypothermia causes scarce mobilization of energy reserves during recovery phase. Antioxidant enzyme activities were not affected by short-thermal stress (7d), while prolonged thermal stress (14d) significantly affected SOD, CAT, and GPx activities. The present study provides important insights into the physiological plasticity of P. vannamei during recovery from thermal stress.

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The early attainment of puberty in heifers is essential for the profitability of the cow-calf farm. This study aimed to evaluate the impact of juvenile average daily gain (ADG) and sire's expected progeny difference (EPD) on puberty of crossbred beef heifers. Sixty Angus × Nellore heifers early weaned (age = 102 ± 4.3 d; initial BW = 103 ± 4.7 kg) were used in a 2 × 2 factorial arrangement. The factor 1 was the sire's EPD for scrotal circumference, in which heifers born from sires with positive EPD were considered precocious (P), and heifers born from sires with negative EPD were considered non-precocious (NP). The factor 2 was the high (HG; ADG = 0.9 kg; ad libitum) and medium ADG (MG; ADG = 0.7 kg) from 3rd to 7th month of age (1st phase). After 1st phase until puberty, all heifers were fed ad libitum (2nd phase). Statistical analysis was performed by SAS. There was an interaction between factors for DMI in the 1st phase (P = 0.02), which PHG heifers had higher DMI than NPHG. There was no effect on puberty rate, BW, age and BCS at puberty comparing HG vs. MG. However, favorable sires' EPD for scrotal circumference induced a higher proportion of puberty (P 87% vs. NP 59%) at 15 months of age. Thus, the ADG in juvenile age did not affect puberty rate, but sires with positive EPD increased puberty rate of Angus × Nellore heifers in heifers fed a high gain diet.

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The present work aimed to evaluate the effects promoted by a phase of compensatory growth on metabolic turnover rate, digestive enzyme activity, and bacterial biota of the Pacific white shrimp Litopenaeus vannamei kept under different feeding regimes. Three treatments were evaluated as follows: 70% feed restriction during 3 (T3) and 6 (T6) days, followed by a period of feeding to satiety, and a control treatment without restriction periods. The results showed a full compensatory growth in treatments T3 and T6 by day 35 of the bioassay. A significant increase in trypsin and lipase (T6) activities was observed during compensatory growth, whereas specific amylase activity was significantly lower in treatment T6 compared to T3 but not significantly different from the control group. To determine the metabolic turnover rate of nitrogen in muscle tissue, an analysis of nitrogen isotope values (δ15N) at natural abundance levels was performed. At the end of the experimental period, shrimp under feed restriction had lower metabolic turnover rates and longer nitrogen residence times (t 50) in muscle tissue, as compared to individuals in the control treatment. Regarding the changes in the bacterial communities in shrimp gut, no significant differences were observed at the phylum level, with Proteobacteria being the most abundant bacteria, followed by Actinobacteria. At family taxa level, Rhodobacteraceae presented the highest relative abundance in all treatments, whereas a decrease in Vibrionaceae was observed in treatments T3 and T6 when compared to control shrimps during compensatory growth. At the genus level, a decrease in Celeribacter, Catenococcus, and Epibacterium, and an increase in Ruegeria and Shimia, were identified in shrimp subjected to feed restriction when compared to control organisms during compensatory growth (day 14). At the end of the experimental period, the evaluated parameters showed similar results as those observed in the control treatment, suggesting a normalization of the metabolism and the physiological state. The present findings contribute to a better understanding on the physiological effects produced during compensatory growth in shrimp, which in turn could assist in the development of improved feeding strategies in benefit of the aquaculture industry.

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This study aimed to evaluate the vegetative growth of the species Coffea canephora from the orthotropic and plagiotropic branches of coffee plants of the botanical varieties Conilon and Robusta under irrigated and non-irrigated conditions during the rainy and dry seasons. The experiment was conducted in the municipality of Ouro Preto do Oeste, Rondônia, Brazil, during two periods defined between October 2019 and October 2021. Branch growth rates (mm day−1) were obtained every 14 days and seasonal growth was plotted in series graphs. Average growth rates for each type of branch were compared by Tukey's test (p ≤ 0.05). Vegetative growth was seasonal during the evaluation periods and seasons and varied according to genetic material and irrigation use. Growth rates were higher in the rainy season, regardless of water management and botanical variety. Irrigation of coffee plants conducted during periods of high temperatures and strong water deficit provided higher growth relative to non-irrigated plants. Furthermore, the growth of coffee plants subjected to non-irrigation was held back during the drought period and was compensated by high growth rates during the rainy season. Plants of the botanical variety Robusta tended to grow more than those of the variety Conilon under water availability conditions (rain or irrigation), considering the climate conditions of the South-Western Amazon.(AU)

Neste estudo objetivou-se avaliar o crescimento vegetativo da espécie Coffea canephora, a partir dos ramos ortotrópicos e plagiotrópicos dos cafeeiros das variedades botânicas Conilon e Robusta, em condições irrigada e não irrigadas, durante as estações de chuva e estiagem. O experimento foi conduzido no município de Ouro Preto do Oeste, Rondônia, Brasil, durante dois períodos definidos entre os meses de outubro de 2019 a outubro de 2021. As taxas de crescimentos dos ramos (mm dia-1) foram obtidas a cada quatorze dias e o crescimento sazonal foi plotado em gráficos em série. As médias das taxas de crescimento para cada tipo de ramo foram comparadas pelo teste de Tukey (p ≤ 0,05). O crescimento vegetativo foi sazonal durante os períodos de avaliação e estações do ano e, variou conforme o material genético e uso da irrigação. As taxas de crescimento foram superiores no período chuvoso, independentemente do manejo hídrico e da variedade botânica. A irrigação de cafeeiros realizada durante as épocas de altas temperaturas e forte déficit hídrico proporcionou maior crescimento em relação a plantas não irrigadas. Além disso, o crescimento dos cafeeiros não irrigados ficou represado durante o período da estiagem e foi compensado pelas altas taxas de crescimento no período das chuvas. As plantas da variedade botânica Robusta, em condições de disponibilidade hídrica, mediante chuva ou irrigação, tenderam a crescer mais do que as da variedade Conilon, considerando as condições climáticas da Amazônia Sul-Ocidental.(AU)

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This study evaluates white muscle growth and in vivo cell proliferation during a fasting and refeeding trial, using pejerrey (Odontesthes bonariensis) as animal model, in order to better understand the cellular basis governing catch-up growth. Experiments consisted of two groups of fish, a control group continuously fed ad libitum, and a group fasted for 2 weeks and then fed for another 2 weeks. We examined how the formation of new muscle fibers and their increase in size were related to muscle precursor cell (MPC) proliferation under both experimental conditions. During fasting, the number of 5-ethynyl-2'-deoxyuridine-positive (EdU+) cells decreased along with myogenic regulatory factor (MRF) mRNA levels related to myoblast proliferation and differentiation, and the muscle stem cell marker Pax7 mRNA level increased. Analysis of myomere cross-sectional area, distribution of muscle fiber sizes and number of fibers per myomere showed that muscle hypertrophy but not hyperplasia was inhibited during fasting. Both higher igf2 mRNA level and the persistence of cell proliferation could be supporting new myofiber formation. In contrast, an exacerbated MPC proliferation occurred during catch-up growth, and this increase in cell number could be contributing to the growth of both pre-existing and newly formed small fibers. The findings that some MPCs proliferate during fasting and that muscle growth mechanisms, hyperplasia and hypertrophy are differentially regulated could help to explain why re-fed fish could grow at faster rates, and why they return to the lost growth trajectory.

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To evaluate the effects of temporary dietary lysine restriction on nursery pigs' growth performance and its economic viability compared to control diets, 144 piglets (21-d-old) were assigned to randomized blocks, with two treatments and twelve replicates. The treatments were control-lys: lysine level as recommended from 21-32 and 32-42 days and low-lys: 90% of the lysine level of the control-lys diets. From 42 to 62 days, all animals received a control diet. From 21 to 32 days, pigs fed low-lys had worse average daily gain (ADG), feed conversion, and 32-d body weight (BW; P ≤ 0.05). From 32 to 42 days, pigs fed low-lys had lower average daily feed intake, ADG, and 42-d BW (P ≤ 0.05). From 42 to 62 days, pigs had similar performance (P > 0.05). Overall (21 to 62 days), pigs fed the low-lys had lower (P <0.05) ADG and final BW. At 27 and 29 days, pigs fed the low-lys diet had a higher (P≤0.05) incidence of diarrhea. The lowest feed cost and the highest economic efficiency index were recorded for the low-lys treatment. However, pigs fed the control-lys presented a 3.9% higher profitability. In conclusion, a temporary reduction of lysine in the diets of nursery pigs followed by an unrestricted diet in the subsequent period led to worse growth performance and lower economic viability.(AU)

Objetivou-se com este estudo avaliar os efeitos da restrição temporária de lisina na dieta sobre o desempenho e viabilidade econômica de leitões em fase de creche. Foram utilizados 144 leitões, distribuídos em blocos ao acaso, com dois tratamentos e 12 repetições. Os tratamentos foram controle-lis, nível de lisina recomendado dos 21 aos 32 e 32 aos 42 dias de idade e baixa-lis, 90% do nível de lisina das dietas controle-lis. Dos 42 aos 62 dias, todos os animais receberam dieta controle. De 21 a 32 dias, leitões alimentados com baixa-lis tiveram pior ganho médio diário (GMD), conversão alimentar e peso corporal aos 32 dias (P≤0,05). Dos 32 aos 42 dias, leitões alimentados com baixa-lis apresentaram menor consumo médio de ração diário, GMD e peso aos 42 dias (P≤0,05). Dos 21 aos 62 dias, leitões alimentados com baixa-lis apresentaram GMD e peso corporal final menores (P≤0,05) quando comparados aos alimentados com controle-lis. At 27 and 29 days of age, pigs fed the low-lys diet had a higher (P≤0.05) incidence of diarrhea Aos 27 e 29 dias, leitões alimentados com baixa-lis apresentaram maior (P≤0.05) indicência de diarreia. O menor custo de alimentação e o maior índice de eficiência econômica foram registrados para baixa-lis. No entanto, os suínos alimentados com controle-lis apresentaram rentabilidade 3,9% maior. Como conclusão, a restrição temporária de lisina nas dietas de leitões piora o desempenho e diminui a viabilidade econômica.(AU)

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Abstract Background: The use of early nutrient-restriction programs in broilers can prevent complications such as increased body fat deposition and its consequences. However, feed restriction not always gives the expected results. Objective: To assess the effect of two levels of feed restriction followed by a re-alimentation period with five increasing nutrient levels on growth performance and immune response of broiler chickens. Methods: A total of 330 animals were used. The treatments were: 25 (T25) and 35% (T35) quantitative feed restriction during the starting period, and 0, 2.5, 5, 7.5, 10, and 15% increased energy and protein contents during the growing and finishing periods. Results: For all the T25 treatments, except for T25-0, feed intake (FI) and body weight gain (BWG) were higher, and feed conversion rate (FCR) was lower (p<0.05) compared to the control treatment. In that group, the response of FI and BWG to the increased nutrient density was mostly quadratic (p<0.001), whereas that of FCR was linear (p<0.001). The FI and BWG results were less homogeneous in the T35 treatments, but FCR was lower compared to the control treatment (p<0.05) in all of them. The FCR showed no differences (p>0.05) between treatments during the finishing period. Conclusion: Feeding a nutrient-dense diet after a period of mild feed restriction gives the best results, while increasing nutrient density after a more severe feed restriction does not improve productive results compared to a standard diet. Carcass traits and immune function were not affected by restriction level or nutrient density.

Resumen Antecedentes: El uso de programas de restricción alimenticia temprana en pollos de engorde puede prevenir el incremento de la deposición de grasa corporal y sus consecuencias. Sin embargo, la restricción alimenticia no proporciona siempre los resultados esperados. Objetivo: Investigar los efectos de dos niveles de restricción alimenticia seguida por un período de realimentación con cinco niveles crecientes de nutrientes sobre el rendimiento productivo y la respuesta inmune de pollos de engorde. Métodos: Se utilizaron 330 animales. Los tratamientos fueron: restricción cuantitativa del 25 (T25) y del 35% (T35) durante el periodo de iniciación y aumento de la energía y contenido proteico de la dieta del 0, 2,5, 5, 7,5, 10 y 15% durante los periodos de crecimiento y finalización. Resultados: Para casi todos los T25 el consumo de alimento (FI) y el aumento de peso corporal (BWG) fueron mayores y el índice de conversión (FCR) menor (p<0,05) en comparación con el control. La respuesta del FI y el BWG al aumento de la densidad de nutrientes en este grupo fue mayoritariamente cuadrática (p<0,001), mientras que en el caso del FCR fue lineal (p<0,001). Los resultados del FI y el BWG fueron menos homogéneos en los T35, pero el FCR fue menor que en el control (p<0,05). El FCR no mostró diferencias (p>0,05) entre tratamientos durante el periodo de acabado. Conclusión: La alimentación con una dieta rica en nutrientes después una restricción ligera proporciona los mejores resultados, mientras que el incremento de la densidad de la dieta después de una restricción severa no mejora los resultados productivos en comparación con una dieta estándar. Las características de la canal y la respuesta inmune no se vieron afectadas por el nivel de restricción o la densidad de nutrientes de la dieta.

Resumo Antecedentes: O uso de programas de restrição precoce de nutrientes em frangos de corte tem o potencial de prevenir complicações como o aumento da deposição de gordura corporal e suas consequências. No entanto, a restrição alimentar nem sempre dá os resultados esperados. Objetivo: Investigar os efeitos de dois níveis de restrição alimentar seguidos de um período de re-alimentação com cinco níveis crescentes de nutrientes no rendimento produtivo e na resposta imune de frangos de corte. Métodos: Foram utilizados 330 animais. Os tratamentos foram: restrição quantitativa de 25 (T25) e 35% (T35) durante o período inicial e aumento do conteúdo energético e proteico da dieta de 0, 2,5, 5, 7,5, 10 e 15% durante os períodos de crescimento e finalização. Resultados: Para todos os tratamentos T25, menos para T25-0, consumo de ração (FI) e ganho de peso corporal (BWG) foram maiores e a taxa de conversão (FCR) foi menor (p<0,05) o controle. A resposta do FI e do BWG ao aumento da densidade de nutrientes nesse grupo foi principalmente quadrática (p<0,001), enquanto no caso da FCR foi linear (p<0,001). Os resultados do FI e do BWG foram menos homogêneos nos tratamentos T35, mas o FCR foi menor que no tratamento controle (p<0,05). O FCR não apresentou diferenças (p>0,05) entre os tratamentos durante o período de terminação. Nenhuma tendência clara foi observada no peso relativo dos órgãos linfóides ou na resposta imune devido aos tratamentos testados. Conclusão: A alimentação de uma dieta rica em nutrientes após um período de restrição leve proporcionou os melhores resultados, enquanto o aumento da densidade de nutrientes na dieta após uma restrição severa não melhorou os resultados produtivos em comparação com uma dieta padrão.

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ABSTRACT Replacement beef heifers in extensive systems of the neotropical savannas of Colombia are low priority animals and are assigned to native savannas and low-quality pastures, with scarcely researched long-term consequences. The study pooled data from four contemporary grazing experiments to determine the effects of low growth rates of heifers on their lifetime production of liveweight gains (LWGs) per year and per hectare (ha) subject to different management strategies. Three growth rates were imposed on grazing heifers during the growing phase (i.e. nine-36 months of age) on Brachiaria humidicola pastures. Upon the end of the previous phase, animals were allocated to a B. humidicola paddock with a reduced stocking rate or introduced to a B. decumbens sward to allow compensatory LWGs during the breeding phase (i.e. cows plus weaned calves). Severely limited heifers allowed to make compensatory growth did not reach the outputs of better fed animals. Regardless of the strategy followed, high producing years tended to be followed by lower production in the following year. Comparison with reasonably fed breeding cows full-time on well-managed B. decumbens showed important and significant differences in favor of the more intensive system over the lifetime of the animals. Over the nine-year period, the systems' beef output (i.e. weaned calves plus cows' LWGs) ranged between 86 and 206 kg/ha/year and demonstrated that a wide array of low input management alternatives is feasible. Beef output increases if the LW of cull cows is considered, particularly if they are allowed a short period of fattening during the rainy reason on a low input pasture.

RESUMEN Las novillas de reemplazo en los sistemas extensivos de cría de los Llanos Orientales de Colombia son animales de baja prioridad para el productor y generalmente se les asignan sabanas nativas o pasturas de baja calidad. Las consecuencias de dicha estrategia de manejo han sido poco investigadas. Este trabajo reunió datos de cuatro experimentos de pastoreo contemporáneos y de largo plazo para estimar el efecto de las bajas tasas de crecimiento sobre la ganancia de peso por año y por hectárea (ha) de novillas sometidas a diferentes estrategias de manejo. Se usaron tres cargas animales durante la fase de crecimiento para lograr tasas de crecimiento contrastantes entre los nueve y 36 meses de edad, con pasturas de baja calidad de Brachiaria humidicola, caracterizadas por bajo contenido de proteína bruta y baja digestibilidad. Durante la fase de cría y reproducción las novillas pasaron a pasturas de B. humidicola o de B. decumbens con cargas reducidas, para permitir ganancias de peso compensatorias. Los animales de menor ganancia durante el crecimiento no lograron ganancias compensatorias que les permitieran alcanzar a aquellos mejor alimentados. Independientemente de la estrategia de alimentación, años de relativamente alta producción fueron seguidos por años de baja producción en forma cíclica. La comparación con animales mejor alimentados con pastura de B. decumbens bien manejada, mostró diferencias considerables y significativas acumuladas durante su vida útil. A lo largo de nueve años de experimentación, la producción de ganancia de peso de vacas más terneros destetos varió entre 86 y 206 kg/ha/año, demostrando las consecuencias de largo plazo del amplio rango de estrategias de manejo experimentadas. La producción de carne en estos sistemas se puede aumentar si se le suma el peso de vacas de descarte, particularmente, si le les permite un periodo de ceba corto durante la estación lluviosa, incluso usando pasturas de calidad baja.

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The effects of feed deprivation were evaluated for 1 week and 2 weeks in Lutjanus guttatus juveniles. A significant reduction in body mass was observed in both feed deprivation schemes, as well as in hepatosomatic, viscerosomatic and mesenteric fat indexes. The composition of fasted fish was characterized by a decrease in lipid content; the liver displayed an intense reduction of lipid reserves in both fasted groups, and increased expression of the lysosomal acid lipase. 1 week after re-feeding, both experimental groups showed an increase in specific growth rate, feed intake and feed conversion ratio. A recovery in hepatic lipid reserves was observed, and the expression of the lysosomal acid lipase decreased, although lipid content in both groups was still significantly lower than in control groups. Hepatic expression of the growth hormone receptor decreased after fasting, and remained low even after the fish were fed, whereas the expression of insulin-like growth factor 1 and 2 increased after fasting and decreased in both groups when fish were fed again. Altogether, these results showed a partial compensatory growth response in L. guttatus juveniles after fasting, with enhanced growth rates and improved feed efficiency. Fish used stored lipid reserves as the main energy source, and the expression of growth-related and lipid mobilization marker genes in the liver showed similar patterns in both fasting schemes. Based on the results, we suggest as much as 1-week fasting intervals during grow-out programmes to reduce visceral fat and increase growth rate in this species.

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The main objective of this study was to evaluate the effect of placement time on the performance of broiler chickens and the development of their gastrointestinal tract. Two methodologies for measuring broiler performance were compared, one considering day of pulling as the first day, the other considering day of placement as the first day. A total of 1,056 one-day old male Cobb® 500 broiler chicks were subjected to treatments of different placement times after pulling from the hatchery: 3, 24, 48, and 72 h. The studied traits were: feed intake, body weight, feed conversion, viability, and gastrointestinal tract development. When day of pulling was considered the first day, feed intake and body weight at 39 days decreased as placement time increased. However, when day of placement was considered the first day, fasting up to 72 h did not have any negative effect on broiler performance at 39 days post-placement. Placement time did not affect yolk sac utilization or liver weight. At nine days post-placement, weights of gizzard + proventriculus, pancreas, and small intestine increased with increasing placement time. At seven days of age, there was no effect of placement time on villus height or crypt depth. It is possible to place broiler chicks up to 72 h post-hatching with no negative effects when day of placement is considered the first day for evaluating broiler performance.(AU)

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