Redox Status, Biochemical Parameters and Mineral Elements Content in Blood of Turkey Hens Fed a Diet Supplemented with Yarrowia lipolytica Yeast and Two Bacillus Species.

The probiotic-prebiotic properties and chemical composition of Yarrowia lipolytica yeast (YL), predisposes it for use as a turkey feed additive. The aim of the study was to determine whether YL in the diet of turkeys would exert more beneficial effect by stimulating antioxidant reactions and increasing mineral availability than Saccharomyces cerevisiae (SC). An additional aim of the study was to test whether the addition of a probiotic bacteria to feed containing Yarrowia lipolytica or Saccharomyces cerevisiae yeast would enhance their effect. The study was conducted on turkeys from seven to 112 days of age to determine the effects of a 3% addition of YL to the diet, as an alternative to the standard SC. It was analysed whether the use of a probiotic (Bacillus licheniformis, Bacillus subtilis) together with yeast would be more effective. Both the yeast (YL or SC) and the probiotic stimulated antioxidant mechanisms (increased CAT; reduced MDA), but the addition of SC was less effective. The inclusion of YL in the feed increased the plasma content of Ca, Mg, Cu, Zn and Fe in the blood turkeys and lowered the content of cholesterol and triacylglycerols. The combined use of yeast (YL or SC) with a probiotic enhances the antioxidant effect while inhibiting of lipid peroxidation. The combined use of yeast with a probiotic can be recommended in cases of stimulation of oxidative reactions (e.g., stress or infection).

The effect of different dietary ratios of arginine, methionine, and lysine on the performance, carcass traits, and immune status of turkeys.

The research hypothesis postulated that the optimal dietary inclusion levels and ratios of lysine (Lys), arginine (Arg), and methionine (Met) can increase the growth potential of hybrid turkeys and limit metabolic disorders that weaken immune function. The experiment was carried out in a full rearing cycle, from 1 to 16 wk of age, in a two-factorial randomized design with 3 levels of Arg and 2 levels of Met (90, 100 and 110% of Arg, and 30 or 45% of Met, relative to the content of dietary Lys), with 6 groups of 8 replicates per group and 18 turkeys per replicate. In the first and second month of rearing, a significant dietary Arg-by-Met interaction was noted for daily feed intake and body weight gain, and a more beneficial effect was exerted by higher Met content and medium Arg content. Throughout the experiment, the higher dietary Met level increased the final body weight (BW) of turkeys (P = 0.001). Different dietary Arg levels had no influence on the growth performance of turkeys, but the lowest level decreased dressing yield (P = 0.001), and the highest level increased the percentage of breast muscles in the final BW of turkeys (P = 0.003). The lowest Arg level (90% of Lys content) undesirably increased the concentration of the proinflammatory cytokine IL-6 (P = 0.028) and decreased globulin concentration (P = 0.001) in the blood plasma of turkeys. The higher dietary Met level (45% of Lys content) increased plasma albumin concentration (P = 0.016). It can be concluded that higher dietary levels of Met (45 vs. 30% of Lys content) and Arg (100 and 110 vs. 90% of Lys content) have a more beneficial effect on the growth performance and immune status of turkeys.