Efeito da densidade de criação e do grupo genético sobre o desempenho e o desenvolvimento ósseo de frangos de corte

The aim of this study was to evaluate the effects of stocking density (10 and 16 birds/m2) and of genetic group (Hybro PG, Isa Label JA57 and Ross 308) on performance, carcass yield and bone development in broiler chickens. A completely randomized design was used, in a 3x2 factorial factorial arrangement (3 genetic groups x 2 stocking densities). Tibia, femur and humerus samples were collected when chickens were 1, 7, 14, 21, 28, 35 and 42 days old. The evaluated parameters were length and width (mm, expressed in absolute values), dry bone weight (g) and Seedor index (dry bone weight divided by bone length, mg/mm). No difference between the genetic groups and the stocking densities was found for most of the parameters evaluated, except for humerus width of the genetic groups Ross 308 and Hybro PG reared at the densities of 10 and 16 birds/m2. Interactions between density and genetic group were not found for animal performance and carcass yield. All variables were increased with chicken age. Small differences were observed in bone development patterns of the genetic groups Ross 308 and Hybro PGEste trabalho foi realizado objetivando-se avaliar o efeito da densidade de criação (10 e 16 aves/m2) e do grupo genético (Hybro PG, Isa Label JA57 e Ross 308) sobre as características de desempenho, rendimento de carcaça e desenvolvimento ósseo de frangos de corte. Foi utilizado um delineamento inteiramente casualizado em um esquema fatorial 3x2 (3 grupos genéticos x 2 densidades de criação). A tíbia, fêmur e úmero foram coletados quando as aves estavam com 1, 7, 14, 21, 28, 35 e 42 dias de idade, sendo mensurados o comprimento e a espessura (mm, expressos em valores absolutos), o peso do osso seco (gramas) e o índice de Seedor (peso do osso seco dividido por seu comprimento, mg/mm). Não houve diferenças entre os grupos genéticos e as densidades de alojamento para a maioria dos parâmetros avaliados, com exceção do diâmetro do úmero para os grupos genéticos Ross 308 e Hybro PG, quando criados nas densidades 10 e 16 aves/m2. Não foram encontradas interações entre densidade e grupo genético para desempenho zootécnico e rendimento de carcaça. Todas as variáveis aumentaram com a idade da ave. Pouca diferença foi observada para os padrões de desenvolvimento ósseo dos grupos genéticos Ross 308 e Hybro P

Plasmonic Gold Decorated MWCNT Nanocomposite for Localized Plasmon Resonance Sensing

The synergism of excellent properties of carbon nanotubes and gold nanoparticles is used in this work for bio-sensing of recombinant bovine growth hormones (rbST) by making Multi Wall Carbon Nanotubes (MWCNT) locally optically responsive by augmenting it optical properties through Localized Surface Plasmon Resonance (LSPR). To this purpose, locally gold nano particles decorated gold–MWCNT composite was synthesized from a suspension of MWCNT bundles and hydrogen chloroauric acid in an aqueous solution, activated ultrasonically and, then, drop-casted on a glass substrate. The slow drying of the drop produces a “coffee ring” pattern that is found to contain gold–MWCNT nanocomposites, accumulated mostly along the perimeter of the ring. The reaction is studied also at low-temperature, in the vacuum chamber of the Scanning Electron Microscope and is accounted for by the local melting processes that facilitate the contact between the bundle of tubes and the gold ions. Biosensing applications of the gold–MWCNT nanocomposite using their LSPR properties are demonstrated for the plasmonic detection of traces of bovine growth hormone. The sensitivity of the hybrid platform which is found to be 1 ng/ml is much better than that measuring with gold nanoparticles alone which is only 25 ng/ml