Deficiência de macrominerais em ovinos no semiárido de Pernambuco

Abstract

Minerals play essential roles in the animal metabolism. It is already known that low serum levels can indicate a mineral deficiency and even if this is mild or moderate, it leads to economic losses due to the negative impacts on the productivity. Because they are familiar with Brazilian pastures, several researchers report that the pastures do not present in their composition the desired mineral levels and, consequently, do not meet the daily needs of ruminants on pasture. Therefore, we always see the need for mineral supplementation of herds. In the Northeast region of Brazil, the extensive rearing system is the main type of small ruminant rearing, which predisposes to the occurrence of deficiency outbreaks of some type of mineral. Thus, our research aimed to characterize the occurrence, the clinical-epidemiological and pathological aspects of deficiencies of some minerals, and sought to understand their consequences for the sheep herd in the state of Pernambuco. In our experiment, we collected serum and saliva from 55 ewes in 6 different farms in the agreste and sertão region of Pernambuco. We determined the levels of Na, K and Cl by colorimetric test, using commercial kits in a semi-automatic biochemical analyzer. Mean serum concentrations ranged from 131.5 ± 13.1 mEq/L to 172.4 ± 9.3 mEq/L for Na, 6.28 ± 1.3 mEq/L to 13.9 ± 1.4 mEq/ L for K and 91.6 ± 54.8 mEq/L to 113.6 ± 1.5 mEq/L for Cl. Mean salivary concentrations ranged from 119.4 ± 9.5 mEq/L to 161.8 ± 15.2 mEq/L for Na, 10.1 ± 3.1 mEq/L to 22.3 ± 2.3 mEq/ L to K, and the Na:K ratio ranged from 6.0 ± 1.3 mEq/L to 11.8 ± 4.1 mEq/L. These results showed that sheep raised on farms in this region are marginally deficient in sodium. In one of the farms studied, the sheep had a severe clinical condition of Na deficiency. The animals showed apathy, voracity for salt, polydipsia, polyuria, dry cough, inappetence, allotriophagy, weakness, difficulty getting up and moving, thinness, dehydration and even death. At necropsy, the rumen content was usually compact, giving this content a clay-like appearance. Drawing the research's attention, four sheep presented adrenal gland hypertrophy, which, on histopathological examination, showed hypertrophy of the glomerulosa zone and loss of architecture, causing disorganization of the adrenocortical cell cords.