ABSTRACT

Two feeding trials were conducted to evaluate growth performance, carcass characteristics,

nutrient digestibility, haematological and serum biochemical parameters of broiler chickens

fed graded levels of onion (Allium cepa) and onion with Bactofort® as eubiotics. Two

hundred and forty (240) day old Ross 308 strain broiler chicks were allotted into five

different dietary treatments with 0, 100, 200, 300 and 400g Allium cepa levels/100kg diet in

the first experiment and 0, 15, 30, 45 and 60g Bactofort® levels added to 200g Allium

cepa/100kg diet in the second experiment. Each treatment had 16 birds per pen replicated

three times in a completely randomized design. Feed and water were given ad libitum while

vaccination and other daily routine managements were duly observed throughout the

experimental period. Data collected were subjected to analysis of variance using Statistical

Analysis System and means were compared using Dunnett’s package. Results of the first

trial showed an insignificant (P>0.05) difference in performance parameters measured

during starter period. At the finisher phase, final body weight (2137.47 – 2223.25g) and

weight gain (1462.05 – 1548.10g) were significantly (P<0.05) higher in treatments receiving

Allium cepa additions compared to the control (0g Allium cepa addition level) which had

2121.53g and 1445.53g respectively while feed intake and feed conversion ratio (FCR) were

similar. Mortality was also higher in the control compared to Allium cepa treatment groups.

200g Allium cepa addition level had significantly (P<0.05) higher live weight (2191.78g),

dressed weight (1541.11g) and dressing percentage (75.16%) compared to the other

treatment groups. However, there were no significant (P>0.05) differences in all

haematological and serum biochemical indices across the treatments except for albumin,

creatinine, aspartate aminotransferase, alkaline phosphatase and total cholesterol. Percent

xv

apparent nutrient digestibilities were also insignificant except for crude fibre and crude

protein. Crude fibre digestibility (87.12%) was better in the treatment receiving 200g Allium

cepa