Fw. Edens et al., PRINCIPLES OF EX OVO COMPETITIVE-EXCLUSION AND IN OVO ADMINISTRATION OF LACTOBACILLUS-REUTERI, Poultry science, 76(1), 1997, pp. 179-196
The data that have been presented indicate that the in ovo use of comp
etitive exclusion (CE) agents is feasible for both chickens and turkey
s. However, there are many pitfalls that await the use of in ovo appli
cation of CE agents, including the use of nonspecies-specific intestin
al microbes and the use of harmful proteolytic, gas-producing and toxi
n-producing intestinal microbes. Of the potential CE agents that have
posthatch application, only Lactobacillus reuteri has been shown to be
safe and effective in terms of not affecting hatchability and in havi
ng a prolonged effect in the hatched chick or poult. Lactobacillus reu
teri administration in ovo increases its rate of intestinal colonizati
on and decreases the colonization of Salmonella and Escherichia coli i
n both chicks and poults. Additionally, mortality due to in-hatcher ex
posure to E, coli or Salmonella is reduced with in ovo L. reuteri. Use
of antibiotics in ovo may preclude the use of co-administered CE agen
ts, but Gentamicin(R) and L, reuteri are a compatible mixture when adm
inistered in ovo in separate compartments. Nevertheless, the intestina
l morphology can be affected by both the CE agent and by antibiotics.
Lactobacillus reuteri both in ovo and ex ovo will increase villus heig
ht and crypt depth, and Gentamicin(R) in ovo causes a shortening and b
lunting of the villus. Both Gentamicins and L, reuteri in ovo suppress
potentially pathogenic enteric microbes, but with diminished antibiot
ic effects shortening and blunting of the intestinal villi does not co
rrect itself. Goblet cell numbers increase significantly on the ileum
villus of chicks treated with Gentamicins in ovo, and this is presumab
ly due to the increase in potentially pathogenic bacteria in the intes
tinal tract. Diminishing antibiotic effects posthatch would then negat
ively affect the absorption of nutrients and reduce growth at least in
a transitory manner. Thus, L. reuteri administration in ovo singly or
in combination with Gentamicin(R) followed by L. reuteri via drinking
water or feed appears to have potential to control many enteric patho
gens in poultry. Additional work in the use of in ovo CE cultures is m
andated because there is a world-wide movement to reduce antibiotic us
e in poultry due to increased microbial resistance to antibiotics. Use
of naturally occurring intestinal bacterial cultures, either in mixed
culture or as single well-defined cultures, has potential for immedia
te use in the poultry Industry.