Screening of Lactic Acid Bacteria Isolated from Chicken Ceca for In vitro Growth Inhibition of Salmonella enteritica Serovar Enteritidis

Effect of direct-fed microbials on culturable gut microbiotas in broiler chickens: a meta-analysis of controlled trials

Objective

This meta-analysis was conducted to evaluate the overall effect of direct-fed microbial (DFM) or probiotic supplementation on the log concentrations of culturable gut microbiota in broiler chickens.

Methods

Relevant studies were collected from PubMed, SCOPUS, Poultry Science Journal, and Google Scholar. The studies included controlled trials using DFM supplementation in broiler chickens and reporting log concentrations of the culturable gut microbiota. The overall effect of DFM supplementation was determined using standardized mean difference (SMD) with a random-effects model. Subgroups were analyzed to identify pre-specified characteristics possibly associated with the heterogeneity of the results. Risk of bias and publication bias were assessed.

Results

Eighteen taxa of the culturable gut microbiota were identified from 42 studies. The overall effect of DFM supplementation on the log concentrations of all 18 taxa did not differ significantly from the controls (SMD = −0.06, 95% confidence interval [−0.16, 0.04], p = 0.228, I² = 85%, n = 699 comparisons), but the 18 taxa could be further classified into three categories by the direction of the effect size: taxa whose log concentrations did not differ significantly from the controls (category 1), taxa whose log concentrations increased significantly with DFM supplementation (category 2), and taxa whose log concentrations decreased significantly with DFM supplementation (category 3). Category 1 comprised nine taxa, including total bacterial counts. Category 2 comprised four taxa: Bacillus, Bifidobacterium, Clostridium butyricum, and Lactobacillus. Category 3 comprised five taxa: Clostridium perfringens, coliforms, Escherichia coli, Enterococcus, and Salmonella. Some characteristics identified by the subgroup analysis were associated with result heterogeneity. Most studies, however, were present with unclear risk of bias. Publication bias was also identified.

Conclusion

DFM supplementation increased the concentrations of some beneficial bacteria (e.g. Bifidobacterium and Lactobacillus) and decreased those of some detrimental bacteria (e.g. Clostridium perfringens and Salmonella) in the guts of broiler chickens.

A novel aflatoxin-binding Bacillus probiotic: Performance, serum biochemistry, and immunological parameters in Japanese quail

Two experiments were performed to screen bacilli isolated from quails for their aflatoxin removal potential and to assess the efficiency of their amelioration of experimental aflatoxicosis. Nonhemolytic bacilli were selected for in vitro aflatoxin B1 (AFB1) removal and conventional probiotic tests. The isolate with the highest scores was selected for assessment in field experiments and was identified as Berevibacillus laterosporus (Bl). In the second experiment, 125 male Japanese quails (21 d old) were divided into 5 groups with 5 replications to compare the toxin removal efficiency of Bl with that of a commercial toxin binder, improved Millbond-TX (IMTX). The experimental groups were as follows: Control (without any feed additive or AFB1); AFB1 (2.5 mg/kg); AFB1+Bl (2.5 mg/kg+10(8) cfu/mL); AFB1+IMTX (2.5 mg/kg+2.5 g/kg); and Bl (10(8) cfu/mL). The greatest BW gain and slaughter and carcass weights were found in the Bl group and the lowest values were observed in the AFB1 group (P<0.05). Feeding AFB1 alone to the chicks resulted in a significant decrease in serum albumin, total protein, and glucose and cholesterol levels but a significant increase in serum uric acid, urea, creatinin and phosphorus (P<0.05). Treatment of birds on AFB1 with Bl restored these to their original levels (P<0.05). AFB1+Bl-fed birds had serum aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and alkaline phosphatase enzyme activity similar to control birds (P<0.05). Antibody titer against Newcastle disease virus was found to be lowest in the AFB1 group but highest in the Bl group (P<0.05). Antibody production against sheep red blood cells was lower in the AFB1 group compared with the AFB1+Bl group (P<0.05). Berevibacillus laterosporus supplementation of the AFB1 diet restored the skin response to 2,4-dinitro 1-chlorobenzene to levels comparable with control birds (P<0.05). It can be concluded that selected indigenous Bl is a promising probiotic with AFB1 removal potential.

The Dietary Effects of Fermented Chlorella vulgaris (CBT(®)) on Production Performance, Liver Lipids and Intestinal Microflora in Laying Hens

Fermented Chlorella vulgaris CBT^® was evaluated for its effects on egg production, egg quality, liver lipids and intestinal microflora in laying hens. One hundred and eight Hy-line Brown layers (n = 108), 80 wk of age, were fed a basal diet supplemented with CBT^® at the level of 0, 1,000 or 2,000 mg/kg, respectively for 42 d. Egg production was measured daily and egg quality was measured every two weeks. Five eggs from each replicate were collected randomly to determine egg quality. Egg production increased linearly with increasing levels of CBT^® supplementation (p<0.05), although there was no significant effect of treatment on feed intake. Egg yolk color (p<0.001) and Haugh unit (p<0.01) improved linearly with increasing dietary CBT^®. Hepatic triacylglycerol level was linearly decreased with increasing dietary CBT^® (p<0.05). The supplemental CBT^® resulted in linear (p<0.001) and quadratic (p<0.01) response in population of cecal lactic acid bacteria. In conclusion, fermented Chlorella vulgaris supplemented to laying hen diets improved egg production, egg yolk color, Haugh unit and positively affected the contents of hepatic triacylglycerol and the profiles of cecal microflora.