ObjectiveThe aim of the present study was to investigate the effect of yeast with bacteriocin and Lactobacillus cultures (mixture of Lactobacillus agilis BCRC 10436 and Lactobacillus reuteri BCRC 17476) supplements, alone or in combination, on broiler chicken performance.MethodsA total of 300, 1-d-old healthy broiler chickens were randomly divided into five treatment groups: i) basal diet (control), ii) basal diet+0.25% yeast (Saccharomyces cerevisiae) (YC), iii) basal diet+0.25% yeast with bacteriocin (BA), iv) basal diet+Lactobacillus cultures (LAB), and v) basal diet +0.25% yeast with bacteriocin+Lactobacillus cultures (BA+LAB). Growth performance, cecal microbiota, cecal fermentation products, and blood biochemistry parameters were determined when chickens were 21 and 35 d old.ResultsThe supplementation of YC, BA, and BA+LAB resulted in a significantly better feed conversion rate (FCR) than that of the control group during 1 to 21 d (p<0.05). The LAB supplementation had a significant effect on the presence of Lactobacillus in the ceca at 35 d. None of the supplements had an effect on relative numbers of L. agilis and L. reuter at 21 d, but the BA supplementation resulted in the decrease of both Lactobacillus strains at 35 d. The BA+LAB supplementation resulted in higher short chain fatty acid (SCFA) in the ceca, but LAB supplementation significantly decreased the SCFA at 35 d (p<0.05). All treatments tended to decrease ammonia concentration in the ceca at 21 d, especially in the LAB treatment group. The BA supplementation alone decreased the triacylglycerol (TG) concentration significantly at 21 d (p<0.05), but the synergistic effect of BA and LAB supplementation was required to reduce the TG concentration at 35 d. The YC supplementation tended to increase the plasma cholesterol at 21 d and 35 d. However, the BA supplementation significantly decreased the cholesterol and low density lipoprotein cholesterol level at 35 d. In conclusion, the BA+LAB supplementation was beneficial to body weight gain and FCR of broiler chickens.ConclusionThe effect of BA and LAB supplementation may be a result of the growth of lactic acid bacteria enhancement and physiological characterization of bacteriocin, and it suggests that the BA and LAB supplementation level or Lactobacillus strain selection should be integrated in future supplementation designs.

The aim of the current study was to investigate the effects of bacteriocin of Ruminococcus albus 7 that is expressed by yeast on growth performance, caecal flora, caecal fermentation and immunity function of broilers. A total of 180, one-day-old healthy broiler chicks were randomly divided into three groups: control, bacteriocin (2·5 g/kg feed) and nosiheptide (NHT) (2·5 mg/kg, as antibiotic control). Growth performance, caecal flora, caecal fermentation products and immunoglobulin (Ig) concentration were determined when chicks were 21 and 35 days old. The gene expression of avian β-defensin (AvBD) and mucin (MUC2) were measured at 35 days old. The supplementation of bacteriocin and NHT had no significant effect on body weight gain (BWG) during the experimental period. Bacteriocin supplementation significantly enhanced the growth of Lactobacillus (P < 0·05) and resulted in higher lactate concentration (P < 0·01) in broiler caeca at 21 days old. Both bacteriocin and NHT supplementation resulted in lower Escherichia coil (P = 0·072) and Enterococcus (P = 0·038) counts than in the control group at 35 days old. The bacteriocin treatment group tended to increase bile IgA and showed higher bile IgA than the NHT treatment group (P = 0·059) at 35 days old. Higher levels of AvBD1, AvBD4 and MUC2 gene expression were observed in the NHT treatment group (P < 0·05), but expression of AvBD9 was significantly decreased in both bacteriocin and NHT treatment groups (P < 0·05). In conclusion, bacteriocin supplementation elevated the caecal Lactobacillus counts and affected the immunity function. These benefits suggested that bacteriocin supplementation could be a potential alternative to antibiotics in broiler feed.

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