ABSTRACT High environmental temperature is limiting factor in broiler production. In order to minimize the undesirable consequences of acute or chronic heat stress, the techniques of fixed dietary electrolyte balance and early heat conditioning were evaluated. The objective of this study was to evaluate the possible interactions and effects of dietary electrolyte balance and early heat conditioning on feed intake, body weight, feed conversion ratio, mortality, energy bioeconomic index, fecal moisture, abdominal fat, and breast meat color (L*a*b*) of broilers submitted to chronic or acute heat stress. In total, 1280 chicks, were equally divided in experiment I (chronic heat stress, 6h/day at 32ºC from 35 to 39 d of age) and II (acute heat stress, 36 ºC for 6h at 38 days of age). The data of both experiments were combined and analyzed according to a 2x2x2 factorial arrangement (early heat conditioning (ETC) or not; fixed dietary electrolyte balance (EB) or not; and exposure to acute or chronic heat stress). ETC consisted of exposing 5-d-old birds to 36.0 °C for 24 hours. No interaction among the evaluated factors was detected. Birds exposed to acute heat stress presented significantly higher compared with chronic heat stress. Fixed dietary EB resulted in significantly higher fecal moisture. Lower abdominal fat percentage was obtained in birds exposed to chronic relative to acute heat stress. Higher breast meat L* and b* values were observed in birds exposed to acute heat stress than those submitted to chronic heat stress, indicating worse meat quality.

Several physiological and metabolic changes are triggered in broilers submitted to high environmental temperatures, resulting in performance losses. Feed formulation manipulation of the dietary electrolyte balance may be applied to reduce the negative impact of heat stress on broiler performance. This experiment was carried out to evaluate the effect of the manipulations of dietary electrolytes by combining changes in the electrolyte (Na++K+-Cl-) balance (EB) and in the [(K++Cl-)/Na+] ratio (ER) in broiler feeds. In total, 1575 male broilers between 21 and 46 days old were allotted to 15 treatments in a 5x3 factorial arrangement, consisting of five diets with different EB/ER combinations (150/3, 250/2, 250/3, 250/4, and 350/3). Birds were submitted to heat stress at 25 or 35 days old. Live performance, mortality rate, and carcass traits were evaluated. The strategic formulation of diets with different EB and ER improves live performance and minimize the effect of heat stress on broilers. Under thermoneutral conditions, an EB of 250 mEq/kg and an ER of 3 are recommended, whereas under heat stress, and EB of 350 mEq/kg and an ER of 3 should be applied.

Coleópteros coprófagos são importantes (especialmente Scarabaeidae) para controle biológico de vermes gastrointestinais e de dípteros; dessa forma, são de importância econômica para a pecuária, pois esses besouros utilizam excrementos como alimento e sítio para reprodução. Eles são também de grande utilidade como bioindicadores da diversidade. O objetivo deste trabalho foi avaliar a riqueza em espécies e a abundância de besouros coprófagos, além de verificar se estes atributos são diferentes nos três ambientes (pastagem, agricultura e mata), no município de Dourados-MS. Foram realizadas 105 avaliações semanais, de novembro de 2005 a novembro de 2007, utilizando-se três armadilhas "pitfall" em cada ambiente. Estas foram iscadas com fezes frescas de bovinos. Foram coletados 44.355 adultos de 54 espécies: duas de Hyborosidae e 52 de Scarabaeidae. Cinco espécies foram constantes, muito abundantes e dominantes na pastagem, duas na área agrícola e duas na mata. A maioria das espécies foi considerada acessória, comum e não dominante. A espécie que apresentou maior abundância foi Ataenius platensis Blanchard, 1844. Os índices de diversidade de Shannon-Wiener foram: 2,90, na pastagem; 2,84, na área agrícola, e 2,66, na mata. A presença média de coleópteros coprófagos nas armadilhas positivas nos três ambientes, em indivíduos por armadilha, foi 36,88 (pastagem), 42,73 (área agrícola) e 20,18 (mata). O ambiente de pastagem apresentou maior índice de diversidade. A diversidade foi maior onde houve maior abundância e regularidade de alimentos.

Dung beetles (Coleoptera: Scarabaeoidea) in three landscapes in Mato Grosso do Sul, Brazil. Dung Beetles are important for biological control of intestinal worms and dipterans of economic importance to cattle, because they feed and breed in dung, killing parasites inside it. They are also very useful as bioindicators of species diversity in agricultural or natural environments. The aims of this paper were to study the species richness, and abundance of dung beetles, helping to answer the question: are there differences in the patterns of dung beetle diversity in three environments (pasture, agriculture and forest) in the municipality of Dourados, in the state of Mato Grosso do Sul. A total of 105 samplings were carried out weekly, from November 2005 to November 2007, using three pitfall traps in each environment. The traps were baited with fresh bovine dung, and 44,355 adult dung beetles from 54 species were captured: two from Hyborosidae and 52 from Scarabaeidae. Five species were constant, very abundant and dominant on the pasture, two in the agricultural environment, and two in the environment of Semideciduous forest. Most of the species were characterised as accessories, common and not-dominant. The species with higher abundance was Ataenius platensis Blanchard, 1844. The indexes of Shannon-Wiener diversity were: 2.90 in the pasture, 2.84 in the agricultural environment and 2.66 in the area of native forest. The medium positive presence of dung beetles in the traps in each environment were: 36.88, 42.73 and 20.18 individuals per trap, in the pasture, agricultural environment and in the native forest, respectively. The pasture environment presented a higher diversity index. The species diversity of dung beetles was superior where there was higher abundance and regularity of resource (bovine dung).