ABSTRACT
OBJECTIVE: The objective of this experiment was to compare conventional antioxidants and plant extracts for oxidative stress control in lambs fed a high-concentrate diet. METHODS: Forty-eight male Dorper×Santa Ines lambs with an initial weight of 20±1.49 kg and 60 days of age, were used to evaluate the effects of feeding a combination of Macleaya cordata and Magnolia officinalis plant extracts (0 vs 320 mg/kg dry matter [DM]) in combination with selenium+vitamin E (0 vs 100 IU/kg DM of vitamin E and 0.1 mg/kg DM of selenium) in a completely randomized block design in a 2×2 factorial arrangement. The animals were housed in individual pens and received a high-concentrate diet consisting of 80% whole corn and 20% protein pellet for 60 days. The animals were weighed at the beginning of the experiment and every 14 days for performance monitoring. Three blood samplings were performed during the experimental period for the evaluation of oxidative and protein parameters. RESULTS: The treatments with vitamin E and selenium as additives had a positive influence on final weight, daily weight gain, carcass weight, and selenium content in longissimus muscle (p = 0.01). Plant extracts tended to improve final weight (p = 0.064) and daily weight gain (p = 0.059), showing similar effect as selenium and vitamin E. There was no effect of treatment on blood proteins, indicating that the animals were healthy throughout the experiment. CONCLUSION: The use of plant extracts had a similar effect as the addition of selenium and vitamin E, with dietary inclusion of additives resulting in better performance of lambs but both supplements did not have strong influence on oxidative stress.
ABSTRACT
The objective of this study was to evaluate the effects of different levels of NDF in high-concentrate diets on performance and aspects ruminal, blood, and carcass parameters of finishing lambs. Twenty-four lambs, with initial BW of 24 ± 3 kg, were randomly divided into individual pens, in a completely randomized design, comprising three treatments with eight repetitions each. The treatments consisted of dietary levels of 15%, 20%, and 25% of NDF, based on DM. The diets were composed of corn, soybean meal, minerals, and corn silage and were offered twice a day, with daily control of what was offered and refused, to determine dry matter intake (DMI). The animals were weighed weekly and slaughtered after 50 days of confinement. Performance evaluations, blood parameters, carcass, and ruminal parameters were evaluated. Lambs fed with lower dietary fiber had better carcass yield (P < 0.005). Blood count, blood biochemical parameters, rumen short-chain fatty acid production and protozoan population were not affected by the dietary NDF level. It was concluded that in high-concentrate diets with 15% NDF resulting in better weight gain of the animals in the confinement, good carcass yields without the animal having altered health and ruminal parameters.
