RESUMO
Three experiments were carried out to evaluate the effect of dietary combination of different enzymes (phytase + protease) on performance, metabolizable energy, and amino acid digestibility of broiler chickens fed diets with nutritional reduction. A total of 1,400, 336, and 384 male chickens were distributed in a completely randomized design, in the experiments of performance, metabolism, and digestibility, respectively. Treatments were divided as follows: positive control (PC), negative control - NC1 (PC minus 0.16% Ca, 0.15% available P (aP), and 0.5% crude protein (CP)), NC2 (PC minus 0.16% Ca, 0.15% aP, and 1% CP), NC1 added with phytase deriving from citrobacter and protease deriving from Bacillus licheniformis (CBE), NC1 added with phytase deriving from E. coli and protease deriving from microbial fermentation (SE), NC2 added with CBE, and NC2 added with SE. A protein-free diet was included in the digestibility experiment. The nutritional restriction did not affect feed intake of birds in the first experiment; however, the restriction inhibited body weight gain and feed conversion ratio in all phases. In experiment 2, the nutritional restriction decreased AME and AMEn values, although the addition of phytase and protease in diets improved both parameters, mainly in NC2. Treatment NC2 impaired the standardized digestibility of total essential amino acids of animals subjected to experiment 3, although the addition of enzymes helped to recover the digestibility to levels similar to PC. Supplementation of phytase in association with protease is effective to improve performance, energy metabolism, and standardized amino acid digestibility of broilers fed diets with nutrient restriction.(AU)
Assuntos
Animais , Peptídeo Hidrolases/efeitos adversos , Galinhas/fisiologia , Monoéster Fosfórico Hidrolases/efeitos adversos , Dietoterapia/veterinária , ProteóliseRESUMO
CONTEXT: Natural compounds have been widely studied with the aim of complementing antiophidic serum therapy. OBJECTIVE: The present study evaluated the inhibitory potential of ascorbic acid and a vitamin complex, composed of ascorbic acid, vitamin E, and all the B-complex vitamins, on the biological activities induced by snake venoms. MATERIAL AND METHODS: The effect of vitamins was evaluated on the phospholipase, proteolytic, coagulant, and fibrinogenolytic activities induced by Bothrops moojeni (Viperidae), B. jararacussu, and B. alternatus snake venoms, and the hemagglutinating activity induced by B. jararacussu venom. RESULTS: The vitamin complex (1:5 and 1:10 ratios) totally inhibited the fibrinogenolytic activity and partially the phospholipase activity and proteolytic activity on azocasein induced by the evaluated venoms. Significant inhibition was observed in the coagulation of human plasma induced by venoms from B. alternatus (1:2.5 and 1:5, to vitamin complex and ascorbic acid) and B. moojeni (1:2.5 and 1:5, to vitamin complex and ascorbic acid). Ascorbic acid inhibited 100% of the proteolytic activities of B. moojeni and B. alternatus on azocasein, at 1:10 ratio, the effects of all the venoms on fibrinogen, the hemagglutinating activity of B. jararacussu venom, and also extended the plasma coagulation time induced by all venoms analyzed. DISCUSSION AND CONCLUSION: The vitamins analyzed showed relevant in vitro inhibitory potential over the activities induced by Bothrops venoms, suggesting their interaction with toxins belonging to the phospholipase A2, protease, and lectin classes. The results can aid further research in clarifying the possible mechanisms of interaction between vitamins and snake enzymes.