Effect of zinc bacitracin and salinomycin on intestinal microflora and performance of broilers

Abstract

A feeding experiment was carried out over 42 d with four groups of broiler chickens fed experimental diets formulated to provide no supplementation, 20 mg zinc bacitracin, 60 mg salinomycin, or both feed additives in combination. During the fifth week of the experiment, four chickens from each pen were killed, and the contents of gizzard, duodenum, jejunum, ileum, ceca, and rectum were separately collected and pooled. In all intestinal segments, the pH and the concentration of lactic acid were measured, and the numbers of anaerobic bacteria, coliforms, lactic acid bacteria, lactobacilli, enterococci, and Clostridium perfringens were counted. In homogenates of pancreas obtained from four animals, the activities of amylase, lipase, trypsin, and chymotrypsin were measured. A significant growth-promoting effect was observed in the group receiving zinc bacitracin in combination with salinomycin. Zinc bacitracin significantly reduced the number of coliform bacteria in the ileum and increased the activities of amylase and lipase in pancreas homogenates. Supplementation with salinomycin and zinc bacitracin, alone or in combination, resulted in significantly lower counts of C. perfringens as well as Lactobacillus salivarius, which was a dominant lactic acid bacterium found in broiler intestinal contents. High numbers of these lactobacilli may play a role in broiler growth depression related to competition in nutrient uptake or impaired fat absorption due to bile acid deconjugation.

The Effect of Thyme Extract on Growth Performance, Digestive Organ Weights and Serum Lipoproteins of Broilers Fed Wheat-Based Diets

“…The increased in cholesterol concentration in the present study could be due to the phenolic compounds of carvacrol and thymol that exhibit considerable antimicrobial activity (Basilico and Basilico, 1999;Hernandez et al, 2004) that may depress fat absorption due to bile acid deconjugation (Engberg et al, 2000).…”

Natural plant extracts and prebiotic compounds as alternatives to antibiotics in broiler chicken diets in a necrotic enteritis challenge model

“…Since the PC group had significantly lower Lactobacillus counts, compared with the challenged control group (NC), it can be speculated that low microbial fermentation activities in the ileal digesta resulted in less volatile fatty acid production. Engberg et al (2000) also observed higher pH and lower lactate concentrations in ileal digesta of broilers fed diets supplemented with salinomycin alone or salinomycin and Zn-bacitracin. The present results also confirmed those of Engberg et al (2002) who found that lactate and acetate are the predominant organic acids produced due to bacterial fermentation in the ileum.…”

Effects of organic acid and probiotic on performance and gut morphology in broiler chickens

“…Gunal et al (2006) reported that the addition of probiotics alone or a combination of probiotics with organic acid mixture treatments to diets decreased ileal and caecal gram-negative bacteria counts at 21 days or at 42 days. Engberg et al (2000) found that Enterococcus faecium (Cylactin) treatments to diets reduced aerobic and coliform bacteria counts. …”

“…and Clostridium perfringens has been reported, with pathogenic microflora being established in the small intestine, thereby competing with the host for nutrients and reducing the digestion of fat and fat-soluble vitamins owing to the deconjugating effects of bile acids (Engberg et al, 2000). This depresses growth performance and increases the incidence of disease.…”