Taninos condensados na dieta de cordeiros.

Abstract

The consumer market is increasingly demanding in relation to the consumption of foods considered healthy and for this reason several studies have been carried out searching for alternatives that promote improvements in the quality of the meat. This study was developed with the aim of evaluating the productive characteristics of lambs fed diets containing condensed tannins, as well as evaluating the meat quality of these animals. 40 non-castrated male SPRD sheep were used, distributed in a completely randomized design with five treatments and eight replications / treatments. The treatments corresponded to inclusion levels of 0, 2, 4, 6 and 8% of condensed tannin (TC) in the dry matter. The experiment had a duration of 75 days preceded by 10 days of adaptation, throughout the experimental period were evaluated the consumption and performance of the animals, was also performed the digestibility test, where were quantified and collected samples of leftovers and feces of each animal during this period. At the end of the experimental period, blood was collected from the animals for the determination of urea, cholesterol, triglycerides, glucose, total proteins, albumin, creatinine, and hepatic enzymes. At the end of the experiment the animals were slaughtered, after carcass weights, commercial cuts, morphometry, meat quality, physicochemical characteristics, fatty acid composition and sensorial attributes were determined. The data were analyzed using SAS® 9.1 software, with polynomial contrasts to evaluate the linear and quadratic effect and the Linear Response Plateau - LRP discontinuity effect of the levels, at 5% significance level. LRP effect was observed up to 4% of TC for the variables of daily consumption, body weight and metabolic consumption of nutritional fractions. The digestibility of the nutrients presented linear decreasing effect, except for non-fibrous carbohydrate, this increased. In the metabolic profile, there was a linear decreasing effect for urea concentrations, and a quadratic negative effect for gamma-glutamyltransferase, the other metabolites were not influenced by the addition of CT in the diet. The content of N consumed, N retained and N urinary presented LRP effect with the inclusion of CT, and the animals of the treatment 6.0 and 8.0% TC presented negative nitrogen balance. LRP effect was observed up to 4% for PF, GPT and GMD. The weights and yields of CQ and CF, AOL, EGS, had linear decreasing effect. Morphometric measures in the carcass had a linear decreasing effect for leg circumference, chest perimeter and croup perimeter, as well as for ICC and the weight of commercial cuts. The pH values had a quadratic positivexiii effect, and the L, a and Chroma color parameters presented linear reduction. The EE content in the meat showed LRP effect up to 4% CT. In the fatty acid profile, the inclusion of up to 8% of TC in MS promoted a linear effect increasing for the fatty acids C12: 0, C16: 1, C18: 0, C18: 1, C18: 2, C18: 3, C20 : 4, C20: 5 and C22: 5, and increasing linear effect for the percentage of PUFA, odd-chain fatty acids and atherogenicity index, Δ9 desaturase enzymes16,18 showed a linear decreasing effect. The sensorial attribute showed only effect for softness, reducing significantly. The inclusion of condensed tannin in the diet becomes feasible, provided that the maximum level of 4% in dry matter is respected, above levels should be avoided, since it causes deleterious effects on consumption, digestibility, and keeps the animals in balance nitrogen. However, when meat quality was related, levels of up to 4% TC did not affect the performance of the animals, nor did they bring advantage and benefit in the profile of fatty acids in the meat, which would be the main objective. Levels above is detrimental to animal production as it reduces the performance of the animals resulting in inferior carcasses.