Effects of Different Antibiotics on Performance, Processing Characteristics, and Parts Yield of Broiler Chickens

Abstract

Broilers were grown to 49 days of age on diets supplemented with bambermycins (BAM, 2.2 ppm), bacitracin methylene disalicylate (BMD, 27.5 ppm), virginiamycin (VM, 11 ppm), or an unmedicated control. Samples of birds were processed for dressing percentage and parts yield. There were no significant (P greater than .05) effects of antibiotics on final body weight, feed conversion, or mortality. In male broilers, BMD and VM significantly (P less than or equal to .05) increased dressing percentage and percentage yield and reduced the skeletal rack as a percentage of postchill weight compared to those fed the nonmedicated control. All antibiotics significantly increased breast skin weight and breast skin as a percentage of postchill weight of as compared with those fed the unmedicated control. In female broilers, BAM and BMD significantly increased dressing percentage and percentage yield and increased breast weight and breast as percentage of postchill weight as compared with those fed the unmedicated control diet. Females fed BMD also had significantly heavier leg quarters and breast skin than those fed the unmediated control. Females fed VM had increased breast skin weight and breast skin as a percentage of postchill weight than those fed the unmedicated control. The results of the present study indicate that antibiotics may influence dressing percentage and parts yield in the absence of improvements in body weight gain or feed utilization.

Virginiamycin and Caloric Density Effects on Live Performance, Blood Serum Metabolite Concentration, and Carcass Composition of Broilers Reared in Thermoneutral and Cycling Ambient Temperatures

“…The VM by E interaction approached significance (P = 0.07) for dressing percentage, suggesting that within the TN environment 15 ppm VM improved (P = 0.07) dressing percent compared with the control and 20 ppm VM supplementation. Izat et al (1989) reported no effect of 11 ppm VM on carcass weight or dressing percentage; however, according to the results of the current study and others (Leeson, 1984;Woodward et al, 1988;Izat et al, 1990) the VM influence on carcass variables is consistent. A reduction of intestinal weight, as a result of antibiotic supplementation have been reported in previous studies (Coates et al, 1955;Jukes et al, 1956;Henry et al, 1986;Izat et al, 1989).…”

Effects of different levels ofAloe veragel as an alternative to antibiotic on performance and ileum morphology in broilers

“…Antibiotic growth promoters have been helpful in improvement of growth performance and feed conversion ratio in poultry (Miles et al, 2006;Dibner and Buttin, 2002;Izat et al, 1990). However, constant treatment of poultry by antibiotic may result in residues of these substances in poultry products and bacteria resistance against treatments in human body.…”

Rethinking our understanding of the pathogenesis of necrotic enteritis in chickens

“…Added in low doses to the feed of farm animals, they have been shown to increase daily weight gain and conversion of feed into body mass, leading to economic advantages for farmers 2,3,4,5 . However, there is an increasing trend to reduce this use of antibiotics in feedstuffs.…”