Changes in the Antioxidant and Mineral Status of Rabbits After Administration of Dietary Zinc and/or Thyme Extract.

This study was aimed at determining the impact of organic zinc (Zn) and thyme extract (TE) administration, given alone or together for 6 weeks, on the antioxidant and mineral status (Zn, Cu, Fe, and Mn) in the plasma and tissues of growing rabbits. A total of 96 rabbits of age 35 days were randomly assigned to one of four treatment groups: a control group (C), a Zn group supplemented with dietary zinc (50 mg/kg), a TE group receiving thyme extract applied in drinking water (1 ml/L), and a Zn + TE group treated with both additives. Lipid peroxidation in the plasma was influenced by Zn intake and in the kidney was affected by both the Zn and TE treatment (P < 0.05). Zn supplementation led to a significant increase in glutathione peroxidase activity (P = 0.017), total antioxidant capacity (P = 0.009) and total thiol groups level (P = 0.047) in the kidney, with the highest values occurring in rabbits receiving the combination Zn + TE. Administration of TE influenced Zn content in the kidney (P < 0.001), while zinc intake decreased Cu concentration in muscle (P = 0.021). In conclusion, the simultaneous administration of organic Zn and TE positively affected the antioxidant response of kidneys and can be used for improving the antioxidant status of growing rabbits.

Black soldier fly larva in Muscovy duck diets: effects on duck growth, carcass property, and meat quality.

The aim of the study was to evaluate the effects of partially defatted black soldier fly (Hermetia illucens, HI) larva meal on the carcass characteristics and meat quality of Muscovy ducks (Cairina moschata domestica). A total of 192 female ducks aged 3 d were divided between 4 dietary treatments (6 pens/treatment; 8 birds/pen), characterized by increasing levels of substitution of corn gluten meal with HI meal (0%, 3%, 6%, and 9%; HI0, HI3, HI6, and HI9, respectively), and reared until 50 days of age. Twelve birds/treatment (2 birds/pen) were slaughtered on d 51 to evaluate the slaughter traits (i.e., carcass, breast, thigh, and organs weights), carcass yield and meat quality. The slaughter weight, hot and chilled carcass weights, and abdominal fat weight showed a quadratic response to HI meal (minimum for the HI6 group, P < 0.05). Dietary HI meal inclusion did not influence the ultimate pH, the color, the proximate composition or the thiobarbituric acid reactive substances (TBARS) values in either the breast or thigh meat. The mineral profile of the meat was slightly affected by the dietary treatment, with a linear increase in the Cu content of the thigh meat (P < 0.05), whereas no differences were observed for Zn, Mn, or Fe. Dietary HI meal inclusion increased the saturated fatty acid rate in the thigh meat (maximum for the HI9 group, P < 0.05), and the monounsaturated and polyunsaturated fatty acid content in the breast meat (maximum for the HI0 and HI9 groups, respectively, P < 0.05). The ∑n-6/∑n-3 ratio decreased linearly in both the breast and thigh meat, with the HI9 group showing the lowest values (P < 0.05). Finally, the heavy metal concentrations were below the EU limits for poultry meat. To conclude, the inclusion up to 9% of partially defatted HI larva meal in the diet of Muscovy ducks did not affect the slaughter traits or the meat quality, although it did affect the meat fatty acid profile.

Bioaccumulation and biosorption of zinc by a novel Streptomyces K11 strain isolated from highly alkaline aluminium brown mud disposal site.

Zinc biosorption and bioaccumulation by a novel extremely Zn tolerant Streptomyces K11 strain isolated from highly alkaline environment were examined. Temperature, similarly as biosorbent preparation, has negligible effect on the biosorption capacity but very strong effect on the process kinetics. Initial adsorption rate increased almost 10 times with the temperature increase from 10 to 50 °C and it was 30 times higher when non-dried biomass was used. The biosorption study revealed that the process was mainly chemically controlled, however at lower temperature intra-particle diffusion played significant role in the zinc biosorption. The experimental data fitted the Langmuir isotherm model with the maximum biosorption capacity 0.75 mmol g-1. The results of bioaccumulation onto a living biomass of Streptomyces K11 indicated very high bioaccumulation capacity of 4.4 mmol g-1. Zinc extracellular uptake (43%) slightly exceeded the intracellular accumulation (36%). High zinc bioaccumulation capacity was obviously related to extremely high zinc tolerance of Streptomyces K11.

Effect of lignin on oxidative stress in chickens fed a diet contaminated with zearalenone.

The effect of lignin supplementation to a diet contaminated with zearalenone (ZEA) on antioxidant status was studied in female chickens of the ISA BROWN laying strain. From the day of hatching to 2 weeks of age, four groups of chickens were fed the same uncontaminated control diet. After 14 days, Group 1 (control) continued to receive the uncontaminated diet, while Group 2 was fed an identical diet enriched with 0.5% chemically modified lignin. Simultaneously, chickens of Group 3 were switched to a diet contaminated with 7.9 mg/kg ZEA and those of Group 4 to an identical contaminated diet supplemented with 0.5% lignin. At 6 weeks of age blood and tissue samples were collected. Feeding of a diet contaminated with a high level of ZEA resulted in elevated glutathione peroxidase (GPx) activity in the duodenal mucosa and kidney tissues, and an increased γ-glutamyltransferase (GGT) activity in the plasma, indicative of oxidative stress. In the liver tissue, no mycotoxin-induced response in GPx and thioredoxin reductase (TrxR) activities occurred, and the malondialdehyde (MDA) level was even reduced. Neither the plasma levels of retinol and α-tocopherol nor the activities of superoxide dismutase in erythrocytes and GPx in blood were affected in birds fed the contaminated diet. The only effect of lignin supplemented to the contaminated feed was that it prevented the increase of GPx activity in the duodenal mucosa as an indicator of oxidative stress.

Effects of dietary form of selenium on its distribution in eggs.

The objective of this experiment was to investigate the selenium distribution in eggs from hens fed diets supplemented with Se from sodium selenite (SS) or selenium-enriched yeast (SY). One-day-old female chickens of Hy-Line Brown breed were randomly divided into four groups according to dietary treatments and, for the subsequent 9 months, were fed diets which differed only in the form or amount of Se supplemented. During the whole experiment, group 1 (control) was fed basal diet (BD) with only background Se level of 0.13 mg/kg dry matter (DM). Diets for groups 2 and 3 consisted of BD supplemented with an Se dose of 0.4 mg/kg DM either in the form of SS or SY, respectively. Group 4 was fed BD supplemented with 0.9 mg Se/kg DM from SY. After 9 months of dietary treatments, the Se levels in egg yolk and albumen from hens fed unsupplemented diet were almost identical whereas eggs from hens given diet supplemented with SS showed significantly higher Se deposition in yolk than in albumen (P < 0.01). On the other hand, the feed supplementation with Se doses 0.4 or 0.9 mg/kg DM from SY resulted in significantly higher Se concentration in albumen than in yolk (both P < 0.001). The total Se amounts in whole eggs from hens in groups 1, 2, 3 and 4 were 5.1, 14.4, 22.7 and 31.6 µg Se/egg thus demonstrating the significantly higher (P < 0.001) selenium deposition in eggs from hens given feed enriched with SY than from birds fed diet with equivalent SS dose. Regardless of dose and source, the selenium supplementation to feeds for groups 2, 3 and 4 resulted in significantly increased α-tocopherol concentration in egg yolk compared to control group 1 (P < 0.001). The presented results demonstrate the different pattern of Se distribution in egg mass when laying hens are fed diets supplemented with inorganic or organic selenium sources.

Effects of excessive selenium supplementation to diet contaminated with deoxynivalenol on blood phagocytic activity and antioxidative status of broilers.

This study examined the effects of excessive dietary supplementation with organic selenium on phagocytic activity and antioxidative status of chickens for fattening fed diet contaminated with deoxynivalenol (DON). Sixty chickens of Ross 308 hybrids were at day of hatching divided into four groups with 15 birds in each. The background DON dietary levels in both negative and positive control groups were 0.2 mg/kg. The complete feed for positive control group was supplemented with Se dose 1 mg/kg in the form of Se-yeast. Group 3 was fed diet with DON level 3 mg/kg while diet for group 4 combined DON level 3 mg/kg with a excessive supplement of Se-yeast (Se dose 1 mg/kg). After 6 weeks of dietary intake, six randomly-chosen chickens from each group were sampled. Feeding of contaminated diet resulted in significantly reduced blood phagocytic activity (19.5 ± 1.1% in the negative control vs. 12.8 ± 0.8% in the DON-treated group, p < 0.05). Se-yeast supplemented to the DON contaminated diet prevented suppression of phagocytic activity. Dietary intake of DON at levels 3 mg/kg did not influence the plasma α-tocopherol level while excessive dietary Se dose reduced it in both Se supplemented groups. Neither the birds of DON-treated group nor the birds from group 4 with DON and Se-yeast showed any response in plasma γ-glutamyltransferase (GGT) activity. Subtoxic dietary level of DON significantly increased the activity of glutathione peroxidase (GPx) in the duodenal mucosa, while additional Se supplementation prevented such a response to mycotoxin. On the other hand, both Se supplemented groups showed significantly elevated GPx activities in blood, liver and kidney, (p < 0.05). The results suggest a potential ability of excessive supplementation of organic selenium to prevent the blood phagocytic activity suppression and changes in GPx activity in duodenal tissue induced in broilers by subtoxic dietary levels of DON.

The effects of organic selenium supplementation on the rumen ciliate population in sheep.

The effect of selenium supplementation on the rumen protozoan population of sheep was demonstrated. Both the total and generic counts of rumen ciliates in sheep fed a diet with basal Se content (70 microg/kg dry matter) were compared to those of animals given feed supplemented with inorganic (disodium selenite) or organic Se (selenized yeast) (310 microg/kg dry matter). The genera of Entodinium, Isotricha, Dasytricha, Ophryoscolex, Diploplastron and Polyplastron occurred in all sheep except for the control, in which Ophryoscolex was not observed. The population of Ophryoscolex caudatus f. tricoronatus was significantly higher in sheep supplemented with organic Se than in animals given inorganic Se (by 160 %). Supplementation of feed with selenized yeast induced significant growth in the Diploplastron population (by 63 %) while no change occurred in sheep given selenite. The populations of Dasytricha ruminantium and Polyplastron multivesiculatum were higher than control in both Se-supplemented groups. The ciliate population of Entodinium spp. was not influenced by Se supplements. Our results suggest a protective effect of Se feed supplementation on the development of some rumen ciliate species in young ruminants.

Urinary selenium excretion in selenite-loaded sheep and subsequent Se dynamics in blood constituents.

Renal selenium excretion in sheep was measured during intravenous infusion of sodium selenite, and the post-infusion dynamics of Se levels in whole blood, plasma and red blood cells (RBC) were investigated for the next 5 days. The plasma Se level increased almost twenty fold with the infusion of Na2SeO3 (from 0.39 +/- 0.02 to 7.83 +/- 0.33 micromol x L(-1), P < 0.001) compared with the baseline value. The selenium concentration in urine (0.07 +/- 0.02 vs. 18.53 +/- 2.56 micromol x L(-1), P < 0.001), the amount of Se excreted (0.14 +/- 0.07 vs. 21.40 +/- 2.31 nmol x min(-1), P < 0.001) and the renal clearance of Se (0.1 9 +/- 0.03 vs. 3.01 +/- 0.34 mL x min(-1), P < 0.001) were found to be highly significantly elevated during selenite loading. The clearance measurements showed no changes in the urinary flow rate or in the glomerular filtration rate. During and at the end of infusion the highest Se level was attained in plasma, followed by whole blood and RBC. The plasma Se level fell rapidly within 10 min after the end of infusion, but the concentration of Se in RBC was stable up to the fourth hour, when it started to decrease too. On day 5 the Se concentrations in plasma, RBC and whole blood were found to be only slightly but still significantly higher than before the selenite infusion. The large disproportion between the infusion rate of Se (8.76 microg x min(-1)) and its renal excretion rate (1.69 microg x min(-1)) found in clearance measurements suggests low glomerular filtration of infused selenium, which might primarily be caused by the binding of selenite metabolites to blood constituents. The presented results confirm the low bioavailability to ruminants of Se from sodium selenite.