Desempenho produtivo e características da carcaça e da carne de bovinos (angus vs nelore) terminados em confinamento com aditivos na dieta e de holandesescastrados em diferentes idades

• Autor(a) principal: Fugita, Carlos Alberto
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1657
• topic: Carne bovina; Característica da carcaça; Óleos essênciais; Aditivo; Nutrição de ruminantes; Levedura; Desempenho; Confinamento; Qualidade da carne; Sistema de Produção; Composição química; Anacardium occidentale; Carvacrol; Ricinus communis; Brasil.; Beef; Carcass traits; Essential Oils; Additive; Ruminant nutrition; Yeast; Performance; Confinement; Meat quality; Production system; Chemical composition; Anacardium occidentale; Carvacrol; Ricinus communis; Brazil.; Ciências Agrárias; Zootecnia

The necessity of obtaining natural products as an alternative to antibiotics used as growth promoters in animal feed causes new researches to evaluate the efficiency of these compounds. The objective of this study was to evaluate the effect of adding natural additives in the diet of cattle finished in feedlots and the effects related to animal production and meat quality. This study was carried out in two experiments: Experiment 1 was conducted to evaluate the performance, carcass characteristics and chemical composition of the Longissimus muscle of 48 bulls (Angus vs. Nellore) finished in feedlot for 94 days, with the inclusion of different additives in the diets. The experiment was conducted in a completely randomized way and distributed into four treatments: Control (TES), essential oils (OLI), confimax (MAX) and yeast (LEV). The bulls had initial average age of 22 months and live weight of 318 ± 30 kg. Bulls were slaughtered with final average weight of 468 ± 45 kg. Roughage/concentrate ratio was 50%. In the OLI treatment, 4 g / animal / day of essential oils from castor and cashew were added to the diet; in the MAX CONFIMAX®) treatment, 10 g / animal / day of a mixture with oregano, castor, cashew and yeast oil was added to the diet; and in the LEV treatment, 5 g / animal / day of yeast was added to the diet. The results were submitted to an analysis of variance. The comparison of means was performed by the Tukey test at 5% significance. MAX treatment resulted in a higher final live weight and daily weight gain than OLI treatment, and the TES and LEV treatments were similar to both treatments. The addition of additives did not alter food intake and feed conversion. The animals in the MAX treatment achieved a greater HCW than those in the OLI treatment. No effect (p> 0.05) was observed with the addition of additives in hot carcass yield, backfat thickness and marbling. The inclusion of additives had no effect on moisture, ash and total lipid levels on the Longissimus muscle. The crude protein levels were higher in the meat from bulls fed MAX and LEV diets. The shear force was modified (p <0.01), animals that received the MAX diet had tenderer meat compared to animals that received the LEV diet. The OLI treatment had lower cooking loss compared to treatment TES. The color parameters were not modified (p> 0.05) with the inclusion of additives in the diet. Most fatty acids in the Longissimus muscle were not altered by the inclusion of additives in the diet. Myristic acid was higher in the TES treatment compared to OLI treatment. Palmitic acid showed higher results in the TES, OLI and MAX diet compared to the LEV diet. The oleic acid was higher in the LEV treatment in comparison with the MAX treatment. The percentage of total SFA, MUFA, PUFA, n-3, n-6, and the ratio between PUFA / SFA and n-6/n-3 were not changed by the inclusion of additives in the diet. The inclusion of a greater number of additives (Confimax) in the diet of cattle (Angus vs. Nellore) showed an improvement in the productive parameters and in some meat quality parameters that were analyzed, in this way, the inclusion of these additives in the diet of cattle in feedlot is recommended. Experiment 2 was carried out to evaluate the effects of castration age (15 d vs. 5 mo), dietary protein level (13% vs. 15%) and lysine/methionine (lys/met) ratio (3.0 vs. 3.4) on meat quality of sixty-four intensively reared Friesian steers. Castration age did not affect meat colour over 12 days of display in a commercial display. Dietary protein level and lys/met ratio had little or no effect on L* and b* parameters of the meat over the display period, but a* values were higher in the meat from animals fed a low protein level and low lys/met ratio diet. Visual acceptability of the meat declined throughout the 9-d display period more rapidly. Differences among the treatments were observed except on day 9. Lipid oxidation of the meat did not differ significantly among the treatment groups; however, consumer acceptability tended to be higher for the meat from steers that were fed a high protein level and high lys/met ratio diet.