Lecture 8 Smith

Performance of Neonate Cockatiels Given Cockatiel Derived Lactobacillus

Presenting Author: Jeanne M. Smith, DVM and Sheikh A. Selim, DVM, MPVM, PhD

Avian Health Services, Placerville, CA and PHL Associates, Davis, CA

Interpretive Review and comments by Dr. Nemetz:

Many lactobacillus products have been marketed over the years to help in the growth of hand-fed baby birds and the assistance of recreating normal bacterial flora during an illness and when a patient in on antibiotics. But, do these products actually work? Does the exogenous lactobacillus species of mammalian (bovine), poultry (chicken) or even psittacine origin have the capacity to create a low pH (acidic) in the recipient's gastrointestinal tract and adhere to the crop lining to do any good? These are the questions Dr. Smith attempted to answer in this study.

Hand-fed psittacine chicks are highly susceptible to gastrointestinal yeast and opportunistic bacterial (coliform) infections. The avicultural community has looked for ways to prevent these infections by using probiotics to give these new chicks the beneficial bacteria they are not able to receive from their parents. Previous research in chickens has shown that administering lactobacilli decreases morbidity, mortality, and fecal shedding when birds are challenged with pathogenic bacteria, but that adherence to the crop epithelium was necessary to produce this beneficial effect from the Lactobacillus. If the lactobacilli do not adhere when the crop empties, there will not be enough left to reinoculate incoming food and serve as a reservoir to attach to the new epithelial cells as the old cells are sloughed. Studies have shown that lactobacilli from mammalian sources do not adhere to the crop epithelium of chickens. Avian lactobacilli isolates vary in their ability to adhere and their ability to lower crop pH. The most protective isolates are those that show the greatest adherence and produce the lowest crop pHs.

A cockatiel origin-Lactobacillus ( Lactobacillus salivarius) was used that was isolated anaerobically from the crop epithelium of a 1-year-old, healthy cockatiel. This was administered before feeding to three groups of incubator-hatched baby cockatiels: a low dose, a high dose, and a control group that received no inoculum. Body weight was measured weekly. Crop pH was measured weekly and cultured to establish bacterial counts. Crop adherence was also established throughout the 6-week study period.

The results demonstrated that the crop pH decreased over a four week period of time in all the groups with and without the lactobacillus inoculum. This must be a natural inherent protective factor. On aerobic cultures, there was a significant decrease in the count of gram negative bacteria, then an increase at day 42 which coincided with the movement of the chicks (stress) from the brooders to the hand feeding tubs. Lactobacillus salivarius did adhere to the crop lining epithelium and did become the predominant bacteria in the crop. Also the high dose group demonstrated greater weight gains at 4-6 weeks of age compared to the low dose group or the controls and an increased count of anaerobic bacteria correlating with a more protective environment.


This paper reviewed and demonstrated that the beneficial effects of Lactobacillus sp. in psittacines must have the following criteria:

  1. The strain must be of avian (psittacine) origin and may need to be of specific species origin.
  2. The strain must be able to create adherence to the crop lining to create any long term beneficial effect.Â

If these two criteria are met, it appears in incubator hatched chicks the following results are possible:

  1. Greater weight gains compared to chicks without a health anaerobic environment.
  2. Decreased risk of gram negative (coliform) bacterial infections.

So, if you are using probiotics in avian patients the take home message is that non-avian strains of Lactobacillus sp. do not have any beneficial effects and perhaps only psittacine derived strains can give the expected protection claimed by many manufacturers.