ABSTRACT
Avaliou-se o efeito de diferentes dietas sobre as características da carcaça e da carne de bovinos de corte em confinamento: dieta composta por silagem de milho e formulação fixa durante o período de confinamento (SMF); dieta composta por silagem de milho e formulação variável durante o período de confinamento (SMV); dieta composta por silagem de cana-de-açúcar e formulação fixa (SCF); dieta composta por silagem de cana-de-açúcar e formulação variável (SCV); SCV na metade inicial do confinamento e SMV no período final (SCV/SMV). O delineamento experimental foi inteiramente ao acaso, com cinco tratamentos e três repetições. Houve maior deposição de gordura renal-pélvica-inguinal (P=0,03), de gordura subcutânea (P=0,06) e de gordura na carcaça (P=0,06) nas dietas com silagem de milho (6,7kg; 6,2mm e 34,6 por cento) em relação àquelas com silagem de cana-de-açúcar (5,3kg; 4,8mm e 31,7 por cento). Houve maior (P=0,05) rendimento de contrafilé e de miolo de alcatra nas dietas com silagem de milho (10 por cento e 6,9 por cento) em relação às com silagem de cana-de-açúcar (9 por cento e 6,6 por cento). Não houve efeito das dietas sobre rendimento de cortes primários (P>0,1), perdas por cocção (P>0,3) e força de cisalhamento (P>0,1). O ajuste da formulação da dieta e a troca de silagem não influenciaram as características de carcaça e da carne. A utilização de silagem de cana-de-açúcar permitiu carcaças com acabamento satisfatório.
The effects of different diets on the carcass and meat characteristics of beef steers in feedlot were evaluated using the following: diet containing corn silage, with fixed formulation during the period of feedlot (CSF); diet containing corn silage, with variable formulation according to the phase of feedlot (CSV); diet containing sugar cane silage with fixed formulation (SCSF); diet containing sugar cane silage, with variable formulation (SCSV); CSV diet in initial half of feedlot and SCSV diet in final half (SCSV/CSV). A completely randomized experimental design with five treatments and three replicates (collective pens) was used. There was higher content of kidney-pelvic-inguinal fat (P=0.03), subcutaneous fat (P=0.06), and fat tissue (P=0.06) deposition in animals fed diets containing corn silage (6.7kg, 6.2mm, and 34.6 percent) as compared to those fed sugar cane silage (5.3kg, 4.8mm, and 31.7 percent). A higher (P=0.05) yield of strip loin and rostbiff ( percent of hindquarter) were measured in carcasses from animals fed diets containing corn silage (10 percent and 6.9 percent) than in carcasses from animals fed diets containing sugar cane silage (9 percent and 6.6 percent). No effects of the diets on yield of primary meat cuts of the carcass (P>0.1), cooking losses (P>0.3), and shear force (P>0.1), with averages of 23.4 percent and 4.4kgf/mIII. The adjustment of the diet formulation as the period of confinement and the exchange of silage did not affect the characteristics of carcass and meat. The use of sugar cane silage allowed carcasses with good finishing.
Subject(s)
Cattle , Meat/analysis , Body Composition/physiology , Diet/methods , Fats/analysis , Saccharum/adverse effectsABSTRACT
Nitric oxide is an important intercellular messenger in the central nervous system. NADPH-diaphorase, reported to be identical to nitric oxide synthase, is prsent in specific groups of cells in several neural tissues, including the retina. We determined NADPH-diaphorase activity in homogenates of the chick embryo retina. The enzyme activity was measured spectophotometrically at 585 nm after incubating retinal total homogenates (100-150 µg protein) with 1mMNADPH and 0.5 mM nitroblue tetrazolium in 50 mMTris buffer, pH8.1, at 37ºC. NADPH-diaphorse was detected in 14-day old retinas and 53-65 per cent of the enzyme activity was inhibited by 3 mM NG-nitro-L-arginine (NARG), the arginine analog. One mM L-N5-(1-iminoethyl)ornithine (NIO) was the most potent inhibitor (63 per cent inhibition) while 3 mM NG-nitro-L-arginine methyl ester (NAME) (33 per cent inhibition) and I mMNG-monomethyl-L-arginine acetate (NMMA) (14 per cent inhbition) were less effective. Enzyme activity was increased by 48 per cent by 2 mM calcium chloride, and effect reversed by 1 mMEGTA or EDTA. Basal enzyme levels were also partially inhibited by the chelators, indicating the presence of calcium-dependent and -independent isoforms of nitric oxide synthase in the retina. The results show that the NADPH-diaphorase assay is sample and sensitive and that the different isoforms of nitric oxide synthase expressed in chick retinal cells during development can be demonstrated