Efeito da nutrição da ovelha e do cordeiro sobre o perfil de ácidos graxos do músculo Triceps brachii de cordeiros

O experimento foi realizado com o objetivo de avaliar o efeito da suplementação da ovelha 30 dias antes do parto, da idade à desmama (45 ou 60 dias) dos cordeiros e do sistema de terminação (em confinamento dieta total ou feno) ou a pasto sobre o perfil de ácidos graxos do músculo Triceps brachii de cordeiros machos não-castrados. O animais foram abatidos com 30 kg de peso corporal ou aos 150 dias de idade. Os cordeiros terminados em confinamento alimentados com feno foram abatidos pela idade e os demais pelo peso corporal. Os teores dos ácidos graxos C15:0, C16:0, C17:0, C16:1, C18:1 e C18:3 no músculo diferiram entre os sistemas de terminação dos cordeiros. O músculo dos cordeiros alimentados com dieta completa apresentou maiores valores de C16:0, C16:1 e C18:1, enquanto o músculo daqueles alimentados com feno e em pastagem apresentou maiores teores de C18:3. A dieta alterou o perfil de ácidos graxos no músculo dos cordeiros. A suplementação das ovelhas 30 dias antes do parto e a idade a desmama não afetaram o perfil de ácidos graxos.

Dinâmica do potássio no solo e nutrição potássica da soja

Potassium deficiency in soybeans has spread iii São Paulo State, Brazil, as a consequence of soil K reserve depletion. Exchangeable and nonexchangeable K dynamics in soil were investigated in order to understand the reserve exaustion and its significance to soybean nutrition. Soybean was grown in 8 1 pots with five soils differing in K and clay contents, in presence or absence of K fertilization. Soil samples were taken at 20 days interval and soybean was harvest at R6. Exchangeable (H2SO4 0,05 N) and nonexchangeable K (boiling HNO3) were estimated in soil sample. Two of the soils were very poor in exchangeable K, and even so there was no response in dry matter due to K fertilization. In spite of some differences in K contents in some of the soybeans parts, generally K absorption was not affected by K fertilization, except in grains. Potassium acumulation in soybean plants were affected by soils, but the response was not closely related to exchangeable K in soil. The main K source to the plants was the HNO3 extrated K, showing that this form is not at all nonexchangeable. After the period of maximum plant demand there was a sharp increase in extractable K in soil showing a tendency to a natural equilibrium.

Selenato e selenito na produção, nutrição mineral e biofortificação com selênio em cultivares de alface

SELENATE and SELENITE on YIELD, MINERAL NUTRITION and BIOFORTIFICATION WITH SELENIUM IN LETTUCE CULTIVARSSelenium is an important antioxidant element associated with physiological processes in plants, microorganisms, animals, and humans. However, its mode of action and essentiality in plants are still disputed. In Brazil, information on Se in agricultural crops is extremely scarce, though there are indications that low levels of Se are being consumed by the population. The objective of this study was to evaluate the effect of selenate and selenite on yield, mineral nutrition and biofortification with Se of lettuce cultivars. The experiment was arranged in a completely randomized factorial design 5 x 3 x 2, with five lettuce cultivars (Maravilha de Verao, Rafaela, Great Lakes, Veneranda, and Vera), three Se concentrations (0, 10 and 20 mu mol L(-1)) and two forms of Se (selenate and selenite), with four replicates. Results indicate that selenate application is more appropriate for biofortification of lettuce cultivars, while the effect of selenite proved to be more toxic. The application of selenate results in increased S shoot concentrations, while selenite reduced P concentrations, and both Se forms decreased micronutrient concentrations. No genotypic variation among lettuce cultivars was observed for Se concentration, and little variation was observed for shoot dry matter yield and S, Mg, Mn, and Fe levels.

Efeitos da nutrição mineral na competição inter e intraespecífica de Eucalyptus grandis e brachiaria decumbens: 1- crescimento

The present work was conducted with the objective to study the effects of mineral nutrition on Eucalyptus grandis and Brachiaria decumbens (#BRADC) growth, when submitted to inter- and intra-specific competition. The treatments consisted of two plants of Eucalypts/pot, two plants of BRADC/pot, and one plant of each species/pot. The plants were nourished with the Hoagland e Arnon (1950) complete solution; with no K, P or N; or only with either N, P or K. Sixty days after growing side by side, no effect of the inter- and intra-specific competition on eucalypts plant high, branch number and leaf dry mass was observed. When mineral nutrition did not limit plant growth (complete solution or solution with no K), intra-specific competition reduced on average, 23% of eucalypts root length, leaf area, and stem and root dry mass, and inter-specific competition reduced, on average, 75% of BRADC dry mass. When mineral nutrition became a limiting factor, no plant competition effect on the parameters studied was detected.

Relação entre comprimento craniocaudal e diãmetro da vesícula embrionária/fetal com idade de gestação por meio de avaliação ultra-sonográfica em ovino da raça Bergamácia

This study aimed to relate embryonic/fetal vesicle diameter (EVD) and crown-rump length (CRL) to gestational age in ewes from the 15 th to the 45 th day of pregnancy. Nineteen adult Bergamácia ewes with synchronized estrus were mated by the same male. Ultrasonographic evaluations were performed every 24 hours from the 15 th to the 30 th day after mating and every five days from the 30 th to the 45 th day using 5.0 and 7.5MHZ linear transducers. Average daily growth of EVD and CRL were 1.40mm and 1.33mm, respectively. The inverse calibration obtained for EVD was: Days = -11 + 50(0.1 + 0.04log EVD) 1/2 with R 2 = 0.85, and for CRL was: Days = 13.63 + 12.5(- 0.71 + 0.16CRL) 1/2 with R 2 = 0.93. Both EVD and CRL obtained by ultrasonography are useful measurements that allow the prediction of gestational age in Bergamácia ewes.

Potencialidades da utilização de taninos na conservação de forragens e nutrição de ruminantes-revisão

This review present a discussion abouth the tannins. The tannins are compounds that have the ability to bind other macromolecules, reducing their availability to animal metabolism. This characteristic can be benefic or deleterious, depending on the tannin concentration degree in the plant and its structure. Positive effects are mainly related with a better use of the dietary protein and an increased efficiency of microbial protein synthesis in the rumen. The use of tannins to reduce ruminal methane emission has been subject of current researches, firmly indicating a decrease of ruminal methanogenesis. However, many of these studies, carried out to evaluate the effects of tannins on forage fermentation and animal metabolism, are based on legume plants, so their results can not be surpassed to studies concerning tanniniferous grasses. By improving the characterization of the profile and reactivity of tannins in tanniniferous forages, such as some sorghum hybrids, as well as conducting experiments to demonstrate the effects of tannins on animal metabolism and performance, the real potential of forages with tannin will be enlightened.

Análise morfológica dos folículos primordiais de ovários de ovino criopreservados em EG, DMSO e sua associaçã o

Objective: Compare the cryoprotectants Dimethyl Sulphoxide (DMSO), Ethylene Glycol (EG) and their association for cryopreservation of sheep ovarian cortex. Methodology: Fragments collected from ovaries were divided into 3 parts. 1. One part from sample was destined for analysis of fresh material. 2. The second part was incubated with solution of freezing having 1,5M EG or 1,5M DMSO or 1,5MEG + 1,5M DMSO and washed for dilution of the cryoprotectants. 3. The third part was submitted to cryopreservation using the same cryoprotectans (EG 1,5M; DMSO 1,5M and EG + DMSO 1,5M) and cryopreserved. In all groups, one part of sample was submitted to pre-antral follicles isolation and the remainder was destined to ultra-structural analysis. Results: After isolation of fresh primordial follicles (control), the percentage of viable follicles was 78,9%. The percentage of viable follicles only exposed to cryoprotectants 1,5M EG, 1,5M DMSO and 1,5M EG + 1,5M DMSO was 77,1%, 68,4% and 60,7% respectively. After cryopreservation were 75%, 60% and 55,6% respectively. Ultra-structural analysis of the primordial follicles derived from fresh ovarian fragments or from fragments just exposed to the cryoprotectants showed similar morphology. However, in frozen samples, alterations of mitochondria were observed in all groups. Despite this, the integrity of the remained organelles was preserved in follicles cryopreserved with EG, while that in others groups (DMSO and association) an excess of vacuolizaton in cytoplasm of oocytes and swelling of nuclear membrane was observed indicating degeneration. Conclusion: The Ehilene Glycol seems to be the cryoprotector more adequated for cryopreservation of sheep ovarian tissue.

Desenvolvimento e nutrição do capim-Tanzânia em função da aplicação de zinco

It was aimed to assess the effects of zinc in the development and nutrition of Tanzania grass. The experimental design used was fully randomized, consisting of six doses of zinc (0, 15, 30, 60, 120 and 240 mg dm'3) and four repetitions. The experimental unit was formed in a vase filled with a Red Latosol dystrophic (Zn = 0.4 mg dm). There were two cuts, the first after 53 days of transplanting seedlings and the second 35 days after the first cut. Was evaluated the concentration of zinc in the soil, the content of zinc leaf, the number of tillers, number of leaves, plant height, the dry mass of the shoot, root system and the whole plant. The doses of zinc influenced the concentration of zinc in soil and plant, and production of dry mass of Tanzania grass, especially the first cut. The Tanzania grass shows high tolerance to the toxicity of zinc, and toxic critical level of 273 mg kg-1.

Omissão de macronutrientes na nutrição e no crescimento da cana-de-açúcar cultivada em solução nutritiva

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fertilizantes orgânicos e resíduo de bauxita na disponibilidade de nutrientes e nutrição da cana-de- açúcar irrigada com água potável e residuária

The objective of this study was to evaluate the effect of organic fertilizers (urban solid waste and swine manure) as a source of nutrients and residue from bauxite processing as a corrective of soil acidity, in area cultivated with sugar cane irrigated with potable water and served in the availability of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S) levels in the soil and plants. For this experiment was carried out in pots, using a Alfisol, assessing the availability of the elements in the 0-20 cm layer and the concentration of these nutrients in the leaves of sugarcane. The data showed that the residues increased the concentrations of Ca and Mg in soil, as the concentration of K was not changed and S was not detected, due to the low concentration in the soil. In the leave +1 of sugarcane the residue of bauxite increased levels of N, P, K, Ca and Mg (15.68, 1.73, 10.43, 3.50 and 1.08 g kg-1, respectively). The application of urban solid waste and swine manure also increased the levels of N, K and Ca (11.56, 9.18 and 2.81 g kg-1, respectively). The quality of irrigation water did not alter the availability of P, K, Ca, Mg and S in the soil as well as the levels of these macronutrients in the plant.

Nutrição e produtividade do crambe em razão da adubação de semeadura na safrinha

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Crescimento inicial e nutrição de cedro (Cedrela fissilis Vell.) em função de doses de nitrogênio

We aimed to evaluate the effects of nitrogen rates in early growth, SPAD index, content and accumulation of nutrients in cedar seedlings. The experiment was carried out in a plastic greenhouse and the seedlings were grown in plastic pots filled with 20 dm-3of Rhodic Hapludox, arranged inrandomized blocks with four replications. Rates of 0, 40, 80, 120 and 160 mg dm-3N were tested. Fertilization up to 160 mg dm-3N promoted increases in SPAD index and early growth of plants, beyond greater absorption of N,P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn. Overall, lower N rates limited growth but not the absorption of nutrients by cedar plants. In leaves, the only nutrien taffected was the B which their content was reduced with increasing of N rate. Increased of nitrogen fertilization changed the Cu distributionin plants, since increased Cu content in roots and reduced their content in stem. Higher N rates promoted higher accumulation of all nutrients due to the increase of dry matter. Nitrogen fertilization changed the dynamic of nutrient absorption in cedar. With 160 mg dm-3N, the amount absorbed followed the order: N>S>Ca>K>Mg>P>Fe>Mn>B> Zn> Cu.

Efeito residual de fontes de fósforo nos atributos químicos do solo, nutrição e produtividade de biomassa da cana-de-açúcar

In tropical regions, the residual effect of phosphate fertilizer source is of crucial importance. This study aimed to evaluate the effects of application of P sources in chemical properties of soil, nutrition and productivity of sugarcane plant and during the first and second ratoon. The sources of P applied in furrows at planting were, triple superphosphate, Arad phosphate, bone meal (100 kg ha-1 P2O5 total) and a control without P, the varieties of sugarcane studied were IAC86-2480 and SP79-1011. A randomized block design in a 4 × 2 factorial was used, with four replications. The study was conducted in the municipality of Alta Floresta-MT, Brazil, in Typic Hapludox. After each cutting, in soil P content, pH and Ca were evaluated. In the plant, the production of green and dry matter of shoots, the concentration of P in the biomass harvested, the export of P and agronomic efficiency of the sources of P were determined. The bone meal had a higher agronomic efficiency resulted in greater accumulation and export of P by crop, higher content of available Ca and P and increase soil pH. The Arad reactive phosphate increased its agronomic efficiency between crop cycles.

Nutrição e produtividade da nogueira-macadâmia em função de doses de nitrogênio

The objective of this work was to evaluate the influence of nitrogen doses on mineral nutrition and yield of macadamia nut (Macadamia integrifolia). The experiment was carried out during three agricultural years, in Jaboticabal, SP, Brazil. The experimental design was a complete block with four replicates. Five doses of N (0, 50, 100, 150, and 200 kg ha-1 per year), applied as urea, were evaluated. The increase in N doses increased the nutrient concentration in the leaves and the yield of nuts and almonds. Ca, Mg, and S contents decreased and the ones of Fe and Mg increased linearly with N fertilization. Nut and almond yields were positively correlated with leaf N concentration, and the range from 14 to 18 g kg-1 allowed the highest yields. The dose of 150 kg ha-1 of N per year provides higher nut yields, without reducing the recovery rate of almonds.

Sistemas de manejo e efeito residual do potássio na produtividade e nutrição do feijão-caupi

Cowpea [Vigna unguiculata (L) Walp] have great social and economic importance for the Para State. It grows well in areas with low precipitation and two crop cycles can be obtained annually. This study aimed to assess the effect of the residual fertilization from a previous culture (Sorghum bicolor L. Moench) and crop systems on cowpea yield and macronutrient concentration on leaves of three cowpea cultivars (BRSMilênio, BRS-Urubuquara e BRS-Guariba). The study was conducted at the UFRA. The treatments were two crop systems (minimum tillage and conventional), four levels of potassium (50, 100, 200 e 300 kg de KCl ha-1 applied to a previous sorghum culture) and the three cowpea cultivars. Treatments were organized as a three (4 x 2 x 3) factor experiment on a randomized complete block design. The soil was a yellow latosol. In each experiment plot five plants were selected to determine shoot dry matter and foliar nutrient concentration. Grain yield was determined after harvesting all plants on the experiment plot. The residual KCl fertilization affected foliar nutrient content, but did not affect shoot dry mass or yield of grain. Yield was higher in the minimum tillage system. Highest yield (1590 kg ha-1) was recorded int the cv. 'Guariba' when 100 kg of KCl ha-1 had been used in the previous crop. The highest content of leaf N and K was found in cowpea under minimum tillage system. The amount of P and Mg were higher in the conventional system whereas the amount of Ca did not change.