Effect of some growth promoters on performance of white and brown bovans layers

Abstract EN

A total number of 570 Bovans hens were used in this experiment.

Hens were classified into two equal strains (White and Brown) of 285 hens each and were divided into 3 treatments, each of 95 hens.

One experimental corn- soybean meal diets was formulated.

The basal diet contained 19.0 % CP and 2800 Kcal ME / Kg diet was fed during the laying period.

Two types of probiotics were supplemented to the diet (2 kg / ton) to study their effects on productive performance commercial laying hens compared to the control diet (without growth promoters):1- Choong Ang Yeast Culture (CYC-100) is a unique live yeast culture product (saccharomyces cerevisiae 1.510x1011 CFU / kg) and 2- More Yeast (MY) is a unique dead yeast culture (saccharomyces cerevisiae).

Hens in all treatments were kept under a similar management system.

The obtained results were summarized as follows : • It can be concluded that Brown Bovans had significantly better feed conversion (FC) and economic of efficiency than White Bovans being 5.60 g feed / g egg mass and 0.747 vs 7.00g feed / g egg mass and 0.723.

The MY treatment had higher economic efficiency of 0.777 than other the treatments.

• The White Bovans had significantly higher egg production % with lower egg weight (EW) than the Brown Bovans being 72.81 % and 54.66g vs 68.80 % and 55.81g, respectively.

Hens fed the diets supplemented with CYC-100 and MY had higher egg production %, EW and egg mass (EM) than those fed the control diet.

The highest egg production %, EW and EM were shown during the period from 29-32 weeks of age being 90.65 %, 60.42 and 4922.05g, respectively.

• White Bovans had significantly higher haematocrit value (Ht %) and haemoglobin value (g / dl) than the Brown Bovans (25.76 % and 9.64g /100ml vs 24.30 % and 9.05g / 100ml, P ≥ 0.05).

Hens fed the MY supplemented diets had lower Ht % and Hb of 24.19 % and 8.87g / 100ml than the other treatments.

• Diets supplemented with both CYC-100 and MY \ had lower cholesterol content than those fed the control diet.

It can be seen that as birds advanced in age and production, both Ht % and Hb gradually increased.

The period from 21-24 weeks of age had the lowest Ht, Hb and cholesterol estimates of 21.55 % 8.13 g / 100 ml and 149.05 mg / dl.