RESUMO
An assumption was made in the study that the optimal inclusion levels and ratios of lysine (Lys), arginine (Arg) and methionine (Met) in diets with Lys content consistent with National Research Council (NRC) recommendations (1994) contribute to stimulate the antioxidant defense system and prevent disorders resulting from the oxidation and nitration of biologically important molecules. The experiment was carried out on 864 one-day-old Hybrid Converter turkeys divided into six experimental groups (8 replicates per group and 18 birds per replicate) receiving different levels of Arg and Met. Chickens from group Arg90Met30 received 90% Arg and 30% Met relative to Lys; Arg90Met45 - 90% Arg and 45% Met relative to Lys; Arg100Met30 - 100% Arg and 30% Met relative to Lys; Arg100Met45 - 100% Arg and 45% Met relative to Lys; Arg110Met30 - 110% Arg and 30% Met relative to Lys and Arg110Met45 - 110% Arg level and 45% Met level relative to the content of dietary Lys. In comparison with turkeys fed diets with moderate Arg content (100% of Lys content), a decrease in dietary Arg level (90% of Lys content) led to a decrease in plasma 3-nitrotyrosine (3-NT) concentration (163.6 vs. 141.0), whereas an increase in dietary Arg level (110% of Lys content) led to an increase in plasma 3-NT concentration (163.6 vs. 202.6). In comparison with turkeys fed diets with moderate Arg content (100% of Lys content), the lowest dietary Arg level (90% of Lys content) decreased superoxide dismutase (SOD) activity in the intestinal wall (19.68 vs. 17.41) and in the liver (11.51 vs. 7.94), increased SOD activity in the blood (507.6 vs. 961.4) and in breast muscles (6.26 vs. 7.43) and increased the concentration of malondiadehyde in breast muscles (1.10 vs. 1.50). An increase in dietary Met content from 30 to 45% of Lys content caused a decrease in plasma protein carbonyl concentration (4.33 vs. 3.8) and catalase activity in breast muscles (54.70 vs. 49.66), and an increase in SOD activity in the liver (8.90 vs. 10.41). The highest dietary Arg level (110% of Lys content) did not induce the oxidation of lipids, proteins or DNA, but it increased the risk of protein nitration. The lowest dietary Arg level (90% of Lys content) deteriorated the antioxidant status of turkeys. Regardless of dietary Arg levels, an increase in Met content from 30 to 45% of Lys content stimulated the antioxidant defense system of turkeys.
Assuntos
Lisina , Metionina , Ração Animal/análise , Animais , Arginina , Galinhas , DNA , Dieta/veterinária , Suplementos Nutricionais , PerusRESUMO
Phytic acid present in raw materials used in distilling industry can form complexes with starch and divalent cations and thus limit their biological availability. The influence of the enzymatic hydrolysis of phytate complexes on starch availability during the alcoholic fermentation process using high gravity (HG) maize mashes was analyzed. Indicators of the alcoholic fermentation as well as the fermentation activity of Saccharomyces cerevisiae D-2 strain were statistically evaluated. Phytate hydrolysis improved the course of the alcoholic fermentation of HG maize mashes. The final ethanol concentration in the media supplemented with phytase applied either before or after the starch hydrolysis increased by 1.0 and 0.6 % v/v, respectively, as compared to the control experiments. This increase was correlated with an elevated fermentation yield that was higher by 5.5 and 2.0 L EtOH/100 kg of starch, respectively. Phytate hydrolysis resulted also in a statistically significant increase in the initial concentration of fermenting sugars by 14.9 mg/mL of mash, on average, which was a consequence of a better availability of starch for enzymatic hydrolysis. The application of phytase increased the attenuation of HG media fermentation thus improving the economical aspect of the ethanol fermentation process.
Assuntos
6-Fitase/química , Etanol/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Amido/química , Zea mays/química , Fermentação , Hidrólise , Amido/metabolismoRESUMO
The objective of this study was to determine the effect of dietary probiotic Pediococcus acidilactici (PA) strain MA18/5M on performance, egg traits, egg cholesterol content, and fatty acid composition in laying hens during a 24-wk period. A total of 222 Hy-Line Brown laying hens, 22 wk of age, were divided into 3 treatment groups. Control group (C) hens were fed a basal diet with no probiotic added. In group PA1, the basal diet was supplemented with PA at 100 mg.kg(-1) of feed for the first 12 wk and 50 mg.kg(-1) feed for the next 12 wk, whereas treatment PA2 was supplemented with 100 mg.kg(-1) feed for the whole trial period. Dietary treatments did not significantly affect the BW, feed intake, and egg production of hens. Pediococcus acidilactici supplementation increased egg weight (P < 0.05), eggshell thickness, eggshell relative weight, and egg specific gravity, and it improved feed efficiency ratio per kilogram of eggs (P < 0.01). Moreover, PA dietary supplementation resulted in a significant (P < 0.05) decrease in the number of broken eggs and eggs without the shell, leading to a significant (P < 0.01) reduction in the number of downgraded eggs (39% for PA1 and 52% for PA2). After 6 mo of probiotic supplementation, significant differences were also found in the fatty acid composition and cholesterol content of egg yolk. The yolk cholesterol content, regardless of PA dose, decreased by more than 10%. The concentrations of total polyunsaturated fatty acids, including linoleic acid and linolenic acid, were significantly higher in treatment PA2 (6.5% increase) than in C and PA1. In conclusion, dietary supplementation of Pediococcus acidilactici MA 18/5M at 100 mg.kg(-1) has potential commercial applications for improvements in hen performance and eggshell quality during the early laying period.