Avaliação nutricional, desempenho e qualidade da carne de bovinos de corte alimentados com dietas contendo glicerina bruta

• Autor(a) principal: Monnerat, João Paulo Ismério dos Santos
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1825
• topic: Biodiesel; Marmoreio; Cruzamento industrial; Biodiesel; Marbling; Industrial crossing; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL

This thesis consists of three experiments. The first experiment was conducted aiming to determine the crude glycerin compounds from the biodiesel industry and the energy value on diets for beef cattle. For the test for determining the energy value of glycerin were used eight cattle, steers, and crossbred with an average initial weight of 334 ± 121.13 kg. The experiment was evaluated following the four-by-four Latin Square design. Within each square, two treatments were implemented according crude glycerin and roughage ratio (5:95 and 15:85 on DM) and two experimental periods. Crude glycerin had 105.4g.kg-1 of moisture and 90.09 g.kg-1 of mineral matter, 805.5 g.kg-1 of glycerol and 160 mg.kg-1 of methanol on DM. For energy values were found 934.46 g.kg-1 and 4.01 and 3.64 for Mcal.kg-1 TDN, digestible and metabolizable energy, respectively. In the second experiment five crossbred bulls were used, with 346 ± 21.42 kg of body weight cannulated in te rumen and abomasum. The experimental design was Latin Square 5 x 5 (five periods and five treatments). Each experimental period had duration of 15d, seven days to adaptation and eight to the collections. Animals were fed a basal diet based containing 50% corn silage and 50% concentrate, in dry matter basis (DM). It was used five diets with five levels of crude glycerin inclusion (0, 5, 10, 15 and 20%DM). Corn was replaced by an equivalent amount of food grade glycerin and corn gluten feed. This study was conducted aiming to evaluate the effect of replacing corn by crude glycerin on feed intake, ruminal and total digestibility, ruminal digestion an passage rate, fermentation characteristics, protein efficiency, microbial protein yield and urinary nitrogenous excretion. Only the EE intake was increased (P < 0.05) by crude glycerin inclusion. Except crude protein (CP) total digestibity, there were effects of glycerin level (P < 0.05) on other digestibilities constituents. Thus the diets energy values were increased (P < 0.05) by glycerin. Passage rate did not differ among the treatments (P > 0.05) but digestion rate of DM, OM and NDFap were linearly increased (P < 0.05). No differences (P > 0.05) in ruminal pH and volatile fatty acid concentration were observed, however ammonia concentration decreased (P < 0.05) among glycerin levels. There was no effect (P > 0.05) of crude glycerin levels on protein efficiency, microbial protein yield and urinary nitrogenous excretion. . It can be concluded Crude glycerin should replace corn up to 20%DM in diets in finishing diets of beef cattle. The third trial consists of two different works. The fist study was developed with the objective of evaluating the effect of replacing corn with crude glycerin on the intake and total apparent digestibility of diet components, performance, carcass traits, yields of commercial cuts, and carcass composition of beef cattle under feedlot conditions. Thirty-four crossbreed Red Angus x Nellore bulls with an average initial weight of 343.9 ± 16.56 kg were used. Four animals that served as the control group were slaughtered at the beginning of the experiment, and the remaining animals (n = 30) were assigned to a complete randomized design with five treatments and six replications per treatments (0, 5, 10, 15 or 20% glycerin inclusion on DM basis). At the end of the experiment all the animals were slaughtered. The insulin was linearly increased (P > 0.05) by the treatments, but the glucose was unaffected. The dry matter feed intake (DMI), nutrients digestibility were unaffected (P>0.05) by treatment. Similarly, glycerin level did not affect (P > 0,05) the empty body average daily body weight gain, carcass daily weight gain, carcass deposition efficiency, carcass composition and physical and chemical composition of carcass gain. Dietary treatments also unaffected (P > 0.05) dressing percentage (59.72 ± 1.2950 %), LM (78.09 ± 7.3424 cm2) a carcass backfat (5.28 ± 2.13 mm). It can concluded that Crude glycerin substitution of corn ground could be included in finishing cattle diet up to 20% of the DM without lead to detrimental effects on intake, growth performance, carcass performance or basic cut yields. In the second study were used carcasses from the previous study. After 24-h chill, data of carcass weight and pH. After carcass data collection, a boneless Longissimus section between the 9th and 11th ribs was removed, vacuum packaged, frozen and held at -200C. No effect of inclusion level of glycerin (P> 0.05) on metabolizable energy intake and insulin to glucose ratio. Similarly, muscle fibers proportions were unaffected by treatment. However, an increased fiber diameter to type I and IIA was observed (P <0.05) in bulls fed with crude glycerin. The final weight to fresht and cold carcass and initial and final pH also were unaffected by treatments. The Warner-Bratzler shear force, myofibrillar fragmentation index and total and collagen solubility were not affected (P> 0.05) by the crude glycerin level. No changes were observed (P > 0,05) to meat losses by the treatments. The grude glycerin level did not affect (P>0.05) the instrumental color of the Longissimus. The means to L *, a * and b * were unaffected. In addition, diets containing up to 20% of crude glycerin on dry matter can be used in diets for finishing beef cattle because it does not lead to detrimental effects on carcass traits and meat quality variables.