Supplements with chelated mineral for cows Nellore: growth performance, oocyte quality and oxidative stres

Abstract Text: Nutrition has a major influence on reproductive performance (expression of estrus, follicular development, quality of gametes, ovulation rate, uterine environment, embryo development, maintenance of pregnancy, etc.). Chelated minerals may provided potential benefits to reproduction , enhancing mineral absorption and retention in animal tissues, improved functioning of dependent enzyme systems of minerals (antioxidant systems) , best performance (higher daily weight gain, feed conversion, lower mortality, greater production of meat, eggs and milk). The objective of this study was to evaluated oocyte quality and production traits in Nelore cows grazing supplemented with Copper, Zinc and Selenium in chelated form. 24 multiparous Nelore cows were used, with 36 months of average age, 395 kg of body weight and body condition score of 4.8. Animals were divided into 2 groups: control group (CG, animals supplemented with inorganic mineral) and Supplemented Group (SG, animals supplemented with zinc, copper and selenium in chelated form). Each group was raised in a paddock of Brachiaria brizantha cv. Marandu, receiving 1 kg of supplement/animal/day. Every two weeks the animals were weighed and body condition score (BCS) was evaluated. During experimental period (99 days), two aspirations (59 and 99 days of supplementation) were performed. Oocytes were assessed as viable and non-viable and follicular fluid levels of oxidative stress was measured by TBARS concentration. The experiment was a completely randomized design and data analyzed by ANOVA with a significance level of 5 %. Chelated minerals supplementation did not affect (P > 0.05) total number of oocytes retrieved (P=0.5028), numbers of viable oocytes (P=0.1449), and body weight (P=0.3587). The use of chelated minerals provided greater BCS at the end of experiment (p = 0.0500, 5.27 ± 0.14 versus 4.83 ± 0.17) and higher gain in body condition score (p = 0.0178, 0.82 ± 0.18 versus. 0.25 ± 0.13). Animals supplemented with chelated minerals showed less oxidative stress in follicular fluid (0.05±0.01 versus 0.09±0.02, P = 0.047). Oral supplementation with minerals zinc, copper and selenium in chelated form at used levels, improved body condition score and reduced oxidative stress in follicular fluid of Nelore cows at pasture during dry - water transition.

Keywords: Body score condition, chelate, oxidative stress