Effects of adding yeast cell walls and Yucca schidigera extract to diets of layer chicks.

This research was conducted to determine the impact of diet supplementation with yeast cell walls and Yucca schidigera extract on the growth performance, antibody titres, and intestinal tissue histology of layer chicks. White, 1-d-old, Hy-Line hybrid chicks (n = 840) were divided into 4 main groups, each comprising 7 replicates of 30 chicks (n = 210): (1) control; (2) 1000 mg/kg yeast cell walls (YCW) added; (3) 1000 mg/kg Yucca schidigera extract (YE) added; and (4) 500 mg/kg YE + 500 mg/kg YCW added. The trial lasted 60 d. Daily weight gain of the chicks was positively affected between d 45-60 in the YE and YCW + YE groups compared with the control group. Overall, feed consumption did not differ between the control and YCW, YE, YCW + YE groups during the 60 d study period. Feed efficiency was better in the YE and YCW + YE groups than in the control group between d 1-60. During the 60 d evaluation period, live weight gain, and final live weight were higher in YE and YCW + YE groups than in the control group. Antibody titres against infectious bronchitis and infectious bursal disease did not differ among the 4 treatments, but those for Newcastle disease were higher in the YE + YCW groups than in the control, YCW and YE groups on d 45. There were differences in intestinal histomorphometry between the 4 treatments. The height of the jejunal and ileal villi was greater in the YE and YCW + YE groups than in the control and YCW groups. It can be concluded that YCW and YE supplementation for layer chicks is beneficial for growth performance and intestinal histology during the 1-60 d growing period.

Effects of Echinacea extract on the performance, antibody titres, and intestinal histology of layer chicks.

1. This research was conducted to determine the effect of diet supplementation with Echinacea extract (cichoric acid) on the growth performance, antibody titres and intestinal tissue histology of layer chicks. 2. White, 1-d-old, Hy-Line hybrid chicks (n = 540) were divided into three treatments, each consisting of 6 groups of 30 chicks (n = 180): (1) control; (2) 2·5 mg/kg cichoric-acid-fed; and (3) 5 mg/kg cichoric-acid-fed. The trial lasted 60 d. 3. While the growth performance of the chicks was depressed between d 1 and 45, it was found to improve between d 45 and 60. 4. Feed consumption was lower in both of the cichoric-acid-fed groups than in the control group between d 1-15 and 15-30, but was higher between d 30 and 45. Overall, mean feed consumption did not differ between the control and cichoric-acid-fed groups during the 60 d study period. 5. During the 60 d evaluation period, live weight gain, feed utilisation rate and final live weight were higher in the control group than in both of the cichoric-acid-fed groups. 6. Antibody titres against infectious bronchitis and infectious bursal disease did not differ between the three groups, but those for Newcastle disease were higher in the 2·5 mg/kg cichoric-acid-fed group than in the control group after 45 d. 7. Height and width of the jejunal villus and the thickness of the muscle layer were lower in the 5 mg/kg cichoric-acid-fed group than in both the control and the 2·5 mg/kg cichoric-acid-fed groups. The height of the ileal villus was also lower in the 5 mg/kg cichoric-acid-fed group than in the other two groups. 8. Echinacea extract supplementation for layer chicks appears not to benefit growth performance and intestinal histology during the growing period.

Effects of dietary copper on production and egg cholesterol content in laying hens.

1. This experiment was carried out to determine the effects of diets supplemented with different amounts of copper on egg production, food intake, food conversion ratio, egg weight, damaged egg ratio, specific gravity, mortality and cholesterol concentration in yolk. The experiment lasted 90 d and 400 Hisex-Brown hens, aged 27 weeks at the start of the study, were used. 2. There were no statistically significant effects of supplementary copper on egg production, food intake or food conversion efficiency. 3. There were no statistically significant differences between the groups in terms of damaged eggs, egg weight, specific gravity and live weight. 4. At the end of the experiment, the lowest yolk cholesterol concentrations were obtained in the 150 kg/kg copper group and the greatest concentrations were in the control group. 5. Consequently, the use of supplementary copper to provide 150 kg/kg in poultry diets was concluded to decrease yolk cholesterol concentrations without any effect on production performance.

Effect of probiotic supplementation on laying hen diets on yield performance and serum and egg yolk cholesterol.

The effects of dietary supplementation of a commercial probiotic (BioPlus 2B) on daily feed consumption, egg yield, egg weight, specific gravity, body weight, feed conversion ratio, serum and egg yolk cholesterol, and serum trigylceride in layer hens were investigated. In 12 replicates, 480 27-week-old Brown-Nick layers were fed with diets containing 0, 250, 500 or 750 mg kg(-1) probiotic for 90 days. When compared with the controls, supplementation of 250, 500 and 750 mg kg(-1) probiotic increased egg production, but decreased the damaged egg ratio (p < 0.05), egg yolk cholesterol and serum cholesterol (p < 0.001) levels. In addition, serum triglyceride levels were reduced by using 500 and 750 mg kg(-1) probiotic supplementation (p < 0.001). Feed conversion ratios were positively affected by supplementation of 250 and 500 mg kg(-1) probiotic compared with controls (p < 0.05). There was no statistically significant difference between the control and all treatment groups on feed consumption, egg weight, specific gravity, body weight, and egg yolk weight.

Effect of dietary probiotic on performance and humoral immune response in layer hens.

1. The effects of dietary supplementation of a commercial probiotic (Protexin) on daily feed consumption, egg yield, egg weight, food conversion ratio and humoral immune response in layer hens were investigated. In 7 replicates, a total of 280 40-week-old layers were given diets containing either 0, 250, 500 or 750 parts per million (ppm) for 90 d. 2. When compared with the controls, the food consumption, food conversion ratio and the proportions of damaged eggs were lower in the group consuming 500 ppm probiotic (P<0.05). 3. There was no significant difference between the controls and the groups receiving 250 and 750 ppm probiotic in food consumption, food conversion ratio and proportion of damaged eggs. Similarly, the egg yield, egg weight, specific gravity, and peripheral immune response showed no statistically significant differences between the groups.