Effect of Different Growth Promoters on the Cecal Microflora and Performance of Broiler Chickens

TrakiaUniversity, Agricultural Faculty, BG-6000 Stara Zagora, Bulgaria


DENEV, S. A., 2006. Effect of different growth promoters on the cecal microflora and performance of broiler chickens. Bulg. J. Agric. Sci., 12: 461-474

The objective of this study was an evaluation of the effects of different growth promoters: probiotic Lacto-Sacc® (Alltech, Inc. USA), nutritive premix Pharmastim and nutritive antibiotic Avilamycin on the cecal microflora and performance of broiler chickens. The experiment was conducted using four feeding groups of one-d-old broiler chicken: Group I: Basal diet without supplement (Untreated control); Groups II, III and IV: Basal diet supplemented with probiotic Lacto-Sacc®, (1.0 kg/t); nutritive premix Pharmastim, (0.3 kg/t); and nutritive antibiotic Avilamycin (5,0 mg/kg), respectively. The addition of Lacto-Sacc® to the basal diet significantly increased the count of lactobacilli and enterococci in the cecum of the broiler chickens and depressed the count of coliforms by the low pH of cecal content. There was no significant difference in the count of lactobacilli, enterococci, and coliforms present in the cecum of the untreated control, Pharmastim and Avilamycin-fed groups. Lacto-Sacc® enhanced growth of beneficial microorganisms, regulated the microbial environment in the cecum. Lacto-Sacc® significantly increased the body weight of broiler chickens (P<0.001), compared to the untreated control and the groups fed Pharmastim and Avilamycin. The Lacto-Sacc®, Pharmastim and Avilamycin supplements improved feed conversion ratio by 8.8,1.1 and 1.9% (P<0.001), compared to the untreated control, respectively.
These results suggested that feed additives based on microorganisms provide an alternative to antimicrobial substances in broiler nutrition. Probiotics, and especially Lacto-Sacc® can reduce or replace antibiotics used for growth promotion in broiler chickens.

Key words: broilers, nutrition, cecal microflora, growth promoters, probiotics, antibiotics

1 This paper was presented as Poster: 1) At the Annual Meeting of the European Association for Animal Production 2004 (EAAP-2004), 5-9 Sep., Bled, Slovenia, Book of Abstracts No 10 (Eds. A. Hofer and etc.), Wageningen Academic Publishers, The Netherlands, pp 362. 2) At the 20th Alltech's Annual Symposium "Nutritional Biotechnology in the Feed and Food Industries" May 24-26, 2004, Lexington, Kentucky, USA. Proceedings of the 20th Alltech's Annual Symposium "Nutritional Biotechnology in the Feed and Food Industries", suppl. 1., (Eds. T.P.Lyons and K. Jacques), pp.46.v