OBJECTIVE To determine effects of in ovo administration of a probiotic on development of the intestinal microbiota of 2 genetic lineages (modern and heritage) of chickens.
SAMPLE 10 newly hatched chicks and 40 fertile eggs to determine intestinal microbiota at hatch, 900 fertile eggs to determine effects of probiotic on hatchability, and 1,560 chicks from treated or control eggs.
PROCEDURES A probiotic competitive-exclusion product derived from adult microbiota was administered in ovo to fertile eggs of both genetic lineages. Cecal contents and tissues were collected from embryos, newly hatched chicks, and chicks. A PCR assay was used to detect bacteria present within the cecum of newly hatched chicks. Fluorescence in situ hybridization and vitality staining were used to detect viable bacteria within intestines of embryos. The intestinal microbiota was assessed by use of 16S pyrosequencing.
RESULTS Microscopic evaluation of embryonic cecal contents and tissues subjected to differential staining techniques revealed viable bacteria in low numbers. Development of the intestinal microbiota of broiler chicks of both genetic lineages was enhanced by in ovo administration of adult microbiota. Although the treatment increased diversity and affected composition of the microbiota of chicks, most bacterial species present in the probiotic were transient colonizers. However, the treatment decreased the abundance of undesirable bacterial species within heritage lineage chicks.
CONCLUSIONS AND CLINICAL RELEVANCE In ovo inoculation of a probiotic competitive-exclusion product derived from adult microbiota may be a viable method of managing development of the microbiota and reducing the prevalence of pathogenic bacteria in chickens.
Objective—To genetically type Campylobacter jejuni
isolates from broiler houses or the external environment
to identify the source of Campylobacter organisms
in broiler chickens.
Sample Population—Environmental samples associated
with broiler chickens, in commercial grow-out
Procedure—Polymerase chain reaction (PCR) was
used to amplify flaB, and the amplicon was digested
with Sau3A to create a restriction fragment length
polymorphism assay; PCR was also used to detect a
transcribed spacer region in the 23S rRNA gene.
Results—Isolates possessing a 23S spacer region
were more prevalent outside broiler houses than
inside. Houses that had previously contained chickens
or lacked biosecurity procedures were more likely
to contain isolates possessing the 23S spacer. One
house contained only isolates possessing the spacer,
whereas an adjacent house contained only isolates
lacking the spacer. The flaB type detected in broiler
houses was different from the type detected in the
environment; however, many isolates within the broiler
houses contained untypable flaB genotypes.
Conclusions and Clinical Relevance—Most isolates
from within houses were genetically distinct from isolates
from outside houses that were examined by
bacteriologic culture, suggesting an undetected
source of C jejuni. Detection of isolates containing
the 23S spacer appeared to be an indicator of environmental
contamination of the houses. The observation
of completely different C jejuni genetic types
simultaneously within adjacent houses suggests that
some types do not compete successfully during the
grow-out period. In addition, the diversity of genotypes
identified within broiler houses indicates the
complexity of the ecologic features of C jejuni in the
chicken environment. (Am J Vet Res 2001;62:190–194)
Objective—To determine which antimicrobials that
are used to treat neonatal foals with septicemia attributable
to Escherichia coli will minimize endotoxin
release from bacteria and subsequent activity of
inflammatory mediators while maintaining bactericidal
Sample Population—Blood samples from 10 healthy
Procedure—Escherichia coli isolates A and B were
isolated from 2 septicemic foals, and minimal
inhibitory concentrations (MIC) were determined for
9 antimicrobials. Five of these antimicrobials were
tested in vitro at 2 and 20 times their respective
MIC. Whole blood or mononuclear cells grown in tissue-
culture media were incubated with 105 colonyforming
units of E coli and each antimicrobial or
saline (0.9% NaCl) solution. After 6 hours, number
of viable bacteria remaining was determined, and
supernatant was tested for endotoxin and tumor
Results—Testing in whole blood was compromised
by bactericidal effects of the blood itself. In mononuclear
cell suspensions, each antimicrobial significantly
reduced the number of viable bacteria to low or undetectable
amounts. Antimicrobials did not differ significantly
in efficacy of bacterial killing. Amikacin used
alone or in combination with ampicillin resulted in significantly
less endotoxin activity than did ampicillin,
imipenem, or ceftiofur alone. There was a correlation
between TNF-α and endotoxin activity.
Conclusions and Clinical Relevance—Aminoglycosides
appear less likely to induce endotoxemia
and TNF-α synthesis during bactericidal treatment of E
coli septicemia, compared with β-lactam antimicrobials.
Use of ampicillin, imipenem, or ceftiofur in the
treatment of septicemic neonatal foals should be
accompanied by appropriate treatment for endotoxemia.
(Am J Vet Res 2002;63:660–668)