Effect of Different Growth Promoters on Lysozyme and Complement Activity of Broiler Chicks


1Thracian University, Department of Animal Genetics, BG-6000 Stara Zagora, Bulgaria
2Thracian University, Department of Microbiology and Dairy Science, BG-6000 Stara Zagora, Bulgaria
3Thracian University, Department of Animal Nutrition, BG-6000 Stara Zagora, Bulgaria


SOTIROV, L., S. DENEV and V. K. GEORGIEVA, 2000. Effect of different growth promoters on Lysozyme and complement activity of broiler chicks. Bulg. J. Agric. Sci., 6: 75-82

The objective of this study was an evaluation of the effects of different growth promoters: probiotic Lacto-Sacc® (Alltech Inc.), nutritive premix Pharmastim® and nutritive antibiotic Avilamycin® on the Lysozyme and complement levels, in particular, on the humoral factors of natural immunity in broiler chicks.
The experiment was conducted using five feeding groups of one-d-old broiler chicks: Group I: Basal diet without supplement (Untreated control); Group II, III, IV and V: Basal diet supplemented with: Lacto-Sacc®, (1 kg/t); Pharmastim®, (0.3 kg/t); and Avilamycin® (5.0 ppm/kg), and 2.5% Lactose in drinking water, respectively.
Immunity stimulating effect was recorded with probiotic Lacto-Sacc, and to some extent, with Lactose. The nutritive premix Pharmastim and nutritive antibiotic Avilamycin at the doses applied did not have a similar effect.
The results suggested that feed additives based on microorganisms provide an alternative to antimicrobial substances in animal nutrition. The probiotics and especially Lacto-Sacc can reduce or replace antibiotics used for growth promotion in broiler chicks.

Key words: growth promoters, probiotics, nutritive antibiotics, lysozyme and complement activity
Abbreviations: LAB = Lactic Acid Bacteria; BSA = Bovine Serum Albumin; APCA = Alternative Pathway for Complement Activation; DS = Diluted Serum