Técnicas de quantificação da síntese microbiana no rúmen: uma revisão

The quantification of the microbial protein synthesis in the ruminants is of great importance to assess the nutritional quality of the diets. The determination of microbial synthesis is achieved through the use of microbial markers, which are classified: internal (by-products of rumen microorganisms) and external (substances administered to animals that are incorporated by rumen microorganisms). Although some advances has occurred lately an ideal marker still need to be developed. So the objective of this review is to detail each of the techniques for estimating microbial protein synthesis in the rumen, and discuss the results obtained using each technique.Quantificar a síntese de proteína microbiana em animais ruminantes é de grande importância para avaliar a qualidade nutritiva das dietas. A determinação dessa síntese se obtém por meio da utilização de marcadores microbianos, os quais são classificados em internos (subprodutos dos microrganismos ruminais) e externos (produtos administrados aos animais que são incorporados pelos microrganismos) e técnicas indiretas. Embora tenham ocorrido avanços ainda não se tem o marcador ideal. O objetivo desta revisão é detalhar a cada uma das vantagens e desvantagens das técnicas para estimar a síntese de proteína microbiana no rúmen e discutir os resultados obtidos utilizando cada técnica

Levedura mista (cerveja + cana-de-açúcar) spray-dry na alimentação de leitões na fase inicial

Three experiments were carried out to deter- mine the nutritional values of the spray-dry yeast sugar cane (LEV35) and mixed (brewer + sugar cane – LEV40) and the inclusion effect on starting pigs diets on performance and economic feasibility. In total digestibility assays were used fifteen barrow pigs with initial body weight of 21.49 ± 4.85 kg were allotted in a completely randomized design. The values of digestible and metabolizable energy as-fed basis for LEV35 and LEV40 were: 2788 and 3455 (kcal/kg); 2761 and 3289 (kcal/kg), respectively. In performance trial were evaluated five inclusions levels of LEV40 (0, 5, 10, 15 and 20 %) utilizing 50 piglets, with initial weight of 14.60 ± 1.28 kg in meal form, distributed in a completely randomized bloc design. In second performance trial were evaluated five inclusions levels of previous assay in meal form or pellet form, using 80 piglets, with initial weight of 15.16 ± 2.00 kg, allotted in a completely randomized factorial 5 x 2. The results indicate that the inclusion of up to 20 % of LEV40 in diets for piglets in the two forms did not affect performance. However, the economic feasibility will depend on the price relationship between the ingredients.Foram conduzidos três experimentos para determinar o valor nutricional das leveduras spray- dry cana-de-açúcar (LEV35) e levedura mista (cerveja + cana-de-açúcar – LEV40) e o efeito da inclusão da LEV40 em rações para leitões sobre o desempenho e viabilidade econômica. No ensaio de digestibilidade total foram utilizados 15 leitões machos castrados, com 21,49 ± 4,85 kg de peso vivo, distribuídos em delineamento inteiramente casualizado. Os valores de energias digestível e metabolizável na matéria natural para a LEV35 e LEV40 foram de 2788 e 3455 (kcal/kg); 2761 e 3289 (kcal/kg), respectivamente. No primeiro ensaio de desempenho foram avaliados cinco níveis de inclusão da LEV40 (0, 5, 10, 15 e 20 %) na forma farelada, utilizando 50 leitões, com peso inicial de 14,60 ± 1,28 kg, distribuídos em delineamento de blocos inteiramente casualizado. No segundo ensaio de desempenho foram avaliados os cinco níveis de inclusão utilizados no ensaio anterior nas formas farelada ou peletizada, utilizando 80 leitões, com peso inicial de 15,16 ± 2,00 kg, distribuídos em delineamento inteiramente casualizado em esquema fatorial 5 x 2. Os resul- tados indicam que a inclusão de até 20 % da LEV40 em rações para leitões nas duas formas não afeta o desempenho. Entretanto, a viabilidade econômica vai depender da relação de preços entre os ingredientes

Effect of the reduction of the crude protein content of diets supplemented with essential amino acids on the performance of piglets weighing 6-15kg

Two experiments were conducted to assess the effect of the reduction of the crude protein (CP) content of diets supplemented with amino acids on piglets weighing 6-15. kg. In the performance experiment (Experiment I), 120 piglets weaned at 21 days of age with initial live weights of 5.95±0.33. kg were distributed into five treatment groups. This grouping followed a randomized block design with eight repetitions and three animals per experimental unit. The treatments consisted of five different diets, in which the CP content were reduced from 21.0% to 15.0% (21.0%, 19.5%, 18.0%, 16.5%, and 15.0% CP); the amino acid requirements of the diet were met by adding L-lysine, DL-methionine, L-threonine, L-tryptophan, L-valine, and L-isoleucine. No differences were found in the variables associated with performance among animals from different treatment groups. Therefore, any of the investigated CP levels can effectively be used in piglet diets supplemented with synthetic amino acids. The essential/nonessential amino acid ratio (EAA:NEAA) increased with the reduction of the CP content, and the best ratio (53:47) was achieved with the diet containing 15% protein. Urea concentrations decreased linearly with protein reduction (Experiment I). To assess the nitrogen balance (Experiment II), 20 crossbred male castrated piglets from a commercial lineage, weaned at 21 days of age, were randomly assigned in two blocks, in which each block had two replicates (four replicates per treatment). The average live weight of the piglets was 10.79±2.19. kg. The animals were housed in metal cages and were distributed into five treatment groups following a randomized block design with four repetitions; the experimental unit consisted of one piglet. The nitrogen excretion and blood and urine urea concentrations decreased linearly (. P < 0.05) with the reduction of CP in the diets, resulting in reduced nitrogen excretion into the environment. © 2014 Elsevier B.V

One sixth of Amazonian tree diversity is dependent on river floodplains

Amazonia’s floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region’s floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon’s tree diversity and its function