Re: Stomach Enzymes in Birds

Subject: Re: Stomach Enzymes in Birds
From: Pat Macwhirter <>
Date: Wed, 29 Jul 1998 17:04:32 +1000
Dear Jenny & list,

Amylase and lipase have been reported in chicken saliva but their
significance is thought to be minor. No enzymes are produced in the crop
but the crop does contain mucous glands which serve to soften food. Enzymes
present in the food itself may provide digestion while residing in the
crop. The proventriculus ('stomach') produces HCl and pepsin. Amylase (and
a number of other enzymes) are produced by the pancreas.

Pigeons and doves produce crop milk which is very low in carbohydrate, 60%
protein, 5% ash and 35% fat. In these birds brooding stimulates prolactin
secretion by the pituitary gland which triggers differentiation of the crop
epithelium around the 6th day of incubation. The epitheial cells accumulate
fat and protein and are shed into the lumen of the crop to give the milk,
which is fed to the squabs for about 2 weeks following hatching. Milk-laden
cells are initially soughed when the crop is empty, ensuring that the milk
is not diluted with adult food. As the chick matures crop milk is fed in
combination with other foods. The nutritional advantage of crop milk has
been suggested as a factor in the pandemic success of the Columbidae.

Fig birds do not produce crop milk. A human chewing food before feeding
helps to soften and moisten it but enzymic digestion is probably not

Kirk Klasing has written and excellent book - Comparative Avian Nutrition
(CAB International, 1998) I highly recommend it.

Pat Macwhirter
Registered Specialist in Bird Medicine
Highbury Veterinary Clinic, 128 Highbury Road, BURWOOD, VICTORIA, AUSTRALIA
Ph: (03) 9808 9011 Fax: (03) 9888 7134

>Further to the question from Annie at Atriplex, about feeding figbirds, and
>my reply about the missing enzymes, I received an email from Lainie Berry
>suggesting the possibility of actually chewing the food before giving it to
>the bird.  Neither of us is certain whether the enzymes which are contained
>in the partly digested fruit fed to a baby figbird, would be the same as
>those in the mouth of a human, which Lainie informs me is amylase.
>Is there anyone out there, who could answer this, as I feel there would be a
>lot of Wildlife carers who would welcome confirmation (or otherwise) that
>they could increase the chances of survival of certain baby birds, by the
>addition of their own saliva.  However, I suspect this could have the
>reverse effect, because of the increased chance of infection being passed to
>the bird too.
>Jenny Bradford, Pomona, Qld
>Jenny B's Flower & Crystal Essences

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