The present study was designed to assess the impact of dietary supplementation of lemongrass essential oil ( LGEO ) on growth performance, carcass traits, liver and kidney function, immunity, antioxidant indices and caecal microbiota of growing quail. A total of 200 Japanese quails at 1-week-old were haphazardly allotted to 5 groups of 40 chicks in five replicates (8 per replicate). The first group was the control group, while LGEO was added at levels of 150, 300, 450, and 600 mg/kg diet in the 2nd, 3rd, 4th and 5th groups, respectively. Dietary supplementation of LGEO (150, 300 and 450 mg/ kg diet) increased body weight at 3 and 5 wk of age, and increased body weight gain during all periods compared with the control group ( P < 0.05). All levels of LGEO improved feed conversion ratio during the periods from 1 to 3 and 1 to 5 wk of age. During 3 to 5 wk, feed conversion ratio was improved in quails fed LGEO (300 and 450 mg/kg diet) compared with the control and other treatments. Carcass traits, plasma globulin, alanine aminotransferase, and urea values did not differ among the treatments ( P > 0.05), but the activity of aspartate aminotransferase in the plasma was significantly decreased ( P < 0.05) in LGEO-treated groups. The total protein and albumin values were significantly increased ( P < 0.05) in quails fed levels of LGEO (except 600 mg/kg diet) compared with the control. The inclusion of LGEO in quail diets improved ( P < 0.05) plasma lipid profile. The dietary supplementation of LGEO increased (linear and quadratic, P < 0.05) plasma immunoglobulins (IgM, IgG, and IgA) levels, lysozyme values and activities of superoxide dismutase, total antioxidant capacity, reduced glutathione and catalase compared with the control group. The caecal Coliform, E. coli and Salmonella were lowered ( P < 0.0001) in the quails treated with all LGEO levels, but the total bacterial count and Lactobacillus count were increased with dietary supplementation of LGEO levels (300 and 450 mg/kg) compared with those in the control group. The activities of digestive enzymes were significantly higher in birds fed the diet supplemented with LGEO levels than those fed the control diet. In conclusion, dietary supplementation of LGEO can improve the performance, lipid profile, immunity and antioxidant indices and decline intestinal pathogens and thus boost the health status of growing quail.

Grape seed extracts (GSE) contain several beneficial bioactive constituents; therefore, can be utilized as a potential feed additive in broiler chickens. An experiment was conducted to investigate the effect of supplementation of broiler chicken diets with GSE as a natural antioxidant at levels of 125, 250, 500, 1000 and 2000 ppm on the growth performance, serum lipid profile, liver glutathione-reduced, thigh muscle malondialdehyde and humoral immune response against Newcastle disease virus vaccines. This experiment was performed during the life-span of chickens from 0 to 42 days of age. The results of broilers fed on diet supplemented by GSE were compared with those fed on the basal diet (control) or the basal diet supplemented by butylated hydroxytoluene as a synthetic antioxidant (BHT, 125 ppm). No significant differences were observed in the growth performance, percent livability, total lipid, high and very low-density lipoprotein cholesterols when the use of GSE or BHT were compared with the control. Total cholesterol and low-density lipoprotein cholesterol were significantly decreased after intake of GSE compared with BHT in the feed diet. The glutathione-reduced level in liver tissues was significantly increased by inclusion of GSE, but not by BHT. Inclusion of GSE or BHT decreased significantly the malondialdehyde level found in meat tissue. The antibody titer against Newcastle disease virus vaccines was significantly elevated in 28 and 35-day-old broiler chickens fed with a diet supplemented with GSE or BHT, the former providing a higher response. It can be concluded that GSE can be used as an effective natural antioxidant and immunostimulant agent in broiler chicken diets, and that 125 to 250 ppm can be considered as the optimum dosage.

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A trial was conducted to explore the effect of feeding graded concentrations of green tea extract (GTE; 125, 250, 500, 1000 and 2000 mg/kg) on the growth performance, serum lipid profile, liver glutathione-reduced, thigh muscle malondialdehyde and humoral immune response against Newcastle disease virus vaccines of broiler chickens from hatching to 42 d of age. The results of broilers fed on GTE were contrasted to those fed on butylated hydroxytoluene (BHT; 125 mg/kg) or unsupplemented controls. The obtained results revealed no significant difference among treatments in the measured growth performance parameters (body weight, average daily gain, average daily feed intake and feed conversion ratio), per cent liveability and serum lipid profile (total lipid, total cholesterol, high-density, low-density and very low-density lipoprotein cholesterols). Dietary intake of GTE resulted in a significant increase in the liver glutathione-reduced level compared to the control. The glutathione-reduced level of broilers fed on the BHT diet was not significantly different from that of broilers fed on GTE or control diets. Feeding GTE or BHT resulted in a significant decrease in the malondialdehyde level of meat tissue. The specific antibody titre against Newcastle disease virus vaccines was significantly increased at 28 and 35 d of age in broilers fed on diets supplemented with GTE but not with BHT. In conclusion, GTE was found to possess antioxidant and immunostimulant characteristics for broilers when supplemented to their diets, and its optimum inclusion level ranged from 125 to 500 mg/kg.

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This study examined the effect of dietary treatments containing mannan-oligosaccharides (MOS) on some blood biochemical, haematological parameters and carcass traits of 60 weaned purebred New Zealand White (NZW) and New Zealand White × Rex (NZW × RX) crossbred rabbits. They were assigned to a 2 × 3 factorial arrangement (two genetic groups; and three dietary treatments of zero, 0.5 or 1.0 g MOS/kg of diet). Blood samples have been collected at slaughter at 10 weeks of age. Significant differences were observed among dietary treatments for all biochemical and haematological parameters with the exception of triglycerides. There was a genetic group and dietary treatment interaction for albumen (P < 0.001), cholesterol (P = 0.002), red blood cell count (RBC) (P = 0.007), haemoglobin (Hb) concentration (P = 0.009) and haematocrit % (P < 0.001) observed. Rabbits from the NZW × RX genetic group fed a diet with 1.0 g/kg MOS had the highest plasma cholesterol level (0.97 ± 0.012 mmol/L), whereas the lowest level (0.89 ± 0.012 mmol/L) was detected in rabbits from the NZW × RX genetic group fed the Control diet. Rabbits from the NZW genetic group fed the diet with 1.0 g/kg MOS had the highest RBC (4.27 ± 0.083 × 106/mm3) whereas rabbits from the same genetic group fed the diet with 0.5 g/kg MOS had the highest Hb concentration (11.43 ± 0.097 g/dL) and haematocrit (30.29 ± 0.163%). Some carcass traits such as liveweight, hot and reference carcass weight (P < 0.001), percentage of periscapular, and perirenal fat relative to reference carcass weight (P < 0.05) were significantly affected by the dietary MOS supplementation. In conclusion, MOS supplementation in the diet, especially 1.0 g/kg, improved immunity, health indicators in the blood, liveweights and carcass weights of rabbits without any harmful effects on the other carcass traits. Furthermore, purebred NZW and NZW × RX crossbred rabbits showed relatively similar performance for all traits of interest. A significant interaction between genetic group and dietary supplementation of MOS was shown for albumen, cholesterol, RBC and haematocrit %.

Phytase was examined as a means to improve turkey performance in diets with high Cl by modifying dietary electrolyte balance. Nicholas turkey toms (10 poults/pen; 10 replicates per pen) were fed corn-soy-distillers dried grains with solubles-canola meal-based diets (DDGS/CM) with varying Cl (0.2, 0.3, 0.4, or 0.5%) and phytase (0 or 500 phytase units/kg of diet), making 8 treatments (4 × 2 factorial). A ninth treatment was a corn-soy based diet (CS) with 0.3% Cl and without phytase (positive control). The diets were formulated to contain similar AMEn and digestible amino acid levels for each of 5 feeding periods (2 to 5, 5 to 8, 8 to 11, 11 to 14, and 14 to 17 wk of age) and fed in mash form. Turkey BW, ADG, ADFI, and feed conversion ratio (FCR) were determined for each pen along with litter moisture, foot pad, and gait scores. An ANOVA was conducted to determine the effects of Cl, phytase, and their interaction. Turkey BW, ADG, and ADFI decreased in a linear or curvilinear manner with increasing diet Cl (P < 05). At 17 wk of age, litter moisture and foot pad score showed a cubic trend with diet Cl (P < 0.05). Phytase improved FCR during 8 to 11 wk and increased litter moisture at 11 wk of age (P < 0.003). Phytase modified the FCR response to Cl during 2 to 5 and 14 to 17 wk of age at the 2 lowest levels of dietary Cl (P < 0.05). Turkeys fed CS had better BW and FCR through 17 wk of age compared with those receiving DDGS/CM at 0.3% Cl. Based on BW, minimum dietary electrolyte balance based on Na, K, and Cl was found to be 247, 217, 200, and 171 mEq/kg during 5 to 8, 8 to 11, 11 to 14, and 14 to 17 wk of age, respectively. The present findings emphasized the importance of considering Cl, phytase, and associated dietary electrolyte balance in turkey diets containing high levels of alternative byproducts.