No abstract

No abstract

An experiment was conducted to determine the possibility of using various levels of crude protein (CP) by providing laying hens with constant levels of digestible sulfur amino acid, threonine and lysine to improve performance and egg quality. The experiment was conducted as a completely randomized block design in a factorial arrangement (4×2) with 8 replicates of 10 hens in each. Factors included 4 levels of CP (18.5%, 17.5%, 16.5% and 15.5%) and 2 strains (LSL and Hy-Line W-36) of laying hens. Hens were fed experimental diets from 25 to 33 weeks of age. Production performance was measured for eight weeks and egg quality characteristics were determined at 29 and 33 weeks of age. Protein reduction decreased egg weight, egg mass and hen body weight linearly (P≤0.01). Egg production was not affected by protein reduction but feed efficiency, and average daily feed intake increased significantly (P≤0.01). Lohmann Selected Leghorn laying hens showed significantly higher egg production, egg weight, egg mass, weight gain, feed efficiency and feed intake compared to the W-36 laying hens (P≤0.01). Shell thickness increased linearly as protein levels decreased (P≤0.05). There were significant differences between two strains on the egg quality characteristics (P≤0.01). Significant (P≤0.05) CP × strain interactions were observed for hen weight, albumen height, Haugh units, yolk and shell percentage. Based on the results of this experiment, a reduction in dietary protein level (from 18.5% to 15.5%), without any alteration in digestible TSAA and Thr: Lys ratio, led to inferior egg mass and feed conversion ratio during the peak production period.

No abstract

1. The objective of present study was to evaluate the effects of intra-amniotic injection of different probiotic strains (Bacillus subtilis, Enterococcus faecium and Pediococcus acidilactici) on the intestinal MUC2 gene expression, microbial population, growth performance and immune response in broiler chicken. 2. In a completely randomised design, different probiotic strains were injected into the amniotic fluid of the 480 live embryos (d 18 of incubation), with 4 treatments and 5 replicates. Ileal MUC2 gene expression, microbial profile, growth performance and immune response were determined. 3. Injection of probiotic strains, especially B. subtilis, had significant effect on expression of the MUC2 on d 21 of incubation and d 3 post-hatch, but not on d 19 of incubation. 4. Injection of the probiotic strains decreased significantly the Escherichia coli population and increased the lactic acid bacteria population during the first week post-hatch. 5. Inoculation of probiotics had no significant effect on antibody titres against Newcastle disease virus, antibody titres against sheep red blood cell and cell-mediated immune response of chickens compared to control. 6. In ovo injection of the probiotic strains had no significant effect on growth performance of broiler chickens. 7. It was concluded that injection of probiotic bacteria especially B. subtilis into the amniotic fluid has a beneficial effect on ileal MUC2 gene expression and bacteria population during the first week post-hatch, but has no effect on growth performance and immune response in broiler chickens.

Four hundred broiler chicks were allocated to eight treatments and five replicates in a completely randomized design for 7-42 days. Treatments included basal diet (NC), NC + 1 mg/kg aflatoxin (PC), PC + 1 kg/ton Toxeat® (a toxin binder), PC + Lactobacillus strains (L), PC + Bacillus subtilis JQ 618 strain (B), PC + Saccharomyces cerevisiae's cell wall (Y), PC + B + L + Y (BLY) and PC + hydrated sodium calcium aluminosilicate (HA). At 28 days of age, glucose and total protein serum concentrations in PC group were lower than other treatments (p > .05), but in toxin binder receiving treatments were in the middle of NC and PC groups. At 35 days of age, 48 h after dinitrochlorobenzene injection Y showed more skin swelling (p > .05) and 24 h after injection, the aluminosilicate showed a poor performance with for phytohemagglutinin response. At 35 days, IgG titre and serum cholesterol concentration had a similar process to sheep red blood cell (SRBC) and no significant differences were recorded between aflatoxin inhibitor receiving treatments (p > .05). SRBC, IgG, IgM titres and serum cholesterol concentration at 28 days and IgM titres at 35 days were not affected by treatments (p > .05). It can be concluded that a prebiotics and probiotics mixture such as BLY is suitable for improving immune function and serum biochemical parameters as an effect of feeding aflatoxin-contaminated diet. ARTICLE HISTORY

In this study, 160 73-week-old laying hens (HyLine W-36) were used to investigate the changes in production performance and egg quality parameters of aged laying hens after injection of different doses of growth hormone (GH) and a fixed dose of testosterone (Ts). The hens were weighed individually, placed in laying cages and then randomly assigned to four treatments with four replicates of 10 birds each, in a completely randomised design. The experiment was started at the 75th week and lasted until the 82nd week of age. The treatments were: 1: injection of 100 µL distilled water (control group), 2: injection of 500 µg Ts/kg liveweight + 50 µg GH/kg liveweight, 3: injection of 500 µg Ts/kg liveweight + 100 µg GH/kg liveweight and 4: injection of 500 µg Ts/kg liveweight + 150 µg GH/kg liveweight. In this study, ovulation rate (egg production percent), egg mass and feed intake were significantly higher in Treatment 3 than the control group (P < 0.05), and in Treatment 4, feed conversion ratio was significantly higher than for the other experimental groups (P < 0.05). In addition, the birds in Treatment 3 showed greater egg weight, albumen height, eggshell weight, eggshell density and eggshell weight per surface area than the control group (P < 0.05). In Treatment 3, egg length significantly increased compared with Treatments 1 and 4 (P < 0.05), and in Treatments 2 and 4, shell breaking strength was significantly lower than for the control group (P < 0.05). In conclusion, our results showed positive effects of GH and Ts administration on egg quality parameters and production performance in aged laying hens. Taken together, in the present study Treatment 3 was found more effective in improving egg quality and production performance of the old laying hens.

This experiment was conducted to evaluate the effects of in ovo injection of nano-selenium (Nano-Se) and nano-zinc oxide (Nano-ZnO) and high eggshell temperature (EST) during late incubation on blood parameters of broiler hatchlings. A total of 750 fertile eggs, were weighed and randomly distributed among 5 treatment groups on each of 5 replicate tray levels. The injection was performed on 17 d of incubation. Treatments included of: 1) Eggs not injected and incubated at normal EST (control); 2) Eggs not injected and incubated at high EST; 3) Eggs injected NaCl solution and incubated at high EST (sham); 4) Eggs injected NaCl solution containing 40 µg Nano-Se and incubated at high EST; 5) Eggs injected NaCl solution containing 500 µg Nano-ZnO and incubated at high EST. EST of 37.8ºC (normal) or 38.9ºC (high) was applied from d 19 to 21 of incubation. In ovo injection of Nano-Se and Nano-ZnO significantly increased activity of GSH-Px and SOD and total protein, but decreased the levels of corticosterone, cortisol, T4 and T3 at high EST. Injection of Nano-Se and Nano-ZnO had a significant role in alleviating the negative effects of high temperature incubation and heat stress by increased antioxidant activity and reduced oxidative stress.