Uso de L-glutamina e L-ácido glutâmico na dieta de leitões desmamados em ambiente de conforto e estresse por frio

Abstract

Aimed to through this study to evaluate the influence of the inclusion of L-glutamine and L-glutamic acid in the diet of weaned piglets subjected to different thermal environments (comfort and cold), on performance, physiological variables, organ weights and intestinal morphology. Were used 64 piglets (32 castrated males and 32 females) of Agroceres® commercial line, from 28 to 65 days of age. The animals were distributed in a completely randomized design in a 2x2 factorial arrangement with 4 treatments, two diets (with and without inclusion of L-glutamine and L-glutamic acid) and two thermal environments (comfort and cold), being two animals per experimental unit. Were formulated two experimental diets, a control diet and the other with the inclusion of 1% L-glutamine + L-glutamic acid to meet the requirement of the animals from 28 to 49 days and from 28 to 65 days. The animals were housed in two rooms with controlled temperature to provide a situation of comfort and cold stress (5°C below the comfort temperature), according to the stage of growth of the animals. We evaluated the climatic data, performance, physiological variables, organ weights and intestinal morphology. Through the climate data, the rooms were characterized as thermal stress environment and the other as comfort. Feed intake was lower in the cold environment because the animals stay longer in contact with each other seeking warmth, while with the inclusion of L-glutamine and L-glutamic acid, he was reduced, probably the inclusion caused a reduction the acceptability of the diet. There was interaction of the inclusion of L-glutamine and L-glutamic acid with the thermal environment for the weight gain and feed conversion during 28-49 days and during 28-65 days, and these improved with the inclusion of glutamine source in cold stress conditions, since glutamine is an important energy source for the high turnover of cells. Physiological variables were not affected to interaction, and the respiratory rate and the surface temperature (back, leg, shoulder and belly) were lower in cold environment compared to comfort, because of the thermal exchanges due to the temperature gradient between the animal and environment. There was also no interaction on organ weights; the cold environment promoted increased weight of the heart, liver, lung, kidney and spleen, due to the cold, increases your general metabolism afentando the most active organs, while glutamine generated an increase in the weight of kidneys and spleen, the latter is closely xiii associated with the immune system. There was interaction of the inclusion of glutamine and glutamic acid with the thermal environment for villus height, crypt depth and ratio villus/ crypt, supplementation of glutamine and glutamic acid increased in both environments, since glutamine is the energy source principal of enterocyte. Recommended the use of 1% L-glutamine and L-glutamic acid in the diet of weaned piglets when these may be exposed to environments that provide them with cold stress conditions due to promote improved performance and in the development of duodenal mucosa of animals.