poultry anatomey.poultry diigestive system digestive system of poultry is different from mammals mouth is replaced by peak there is crop

1. Digestive system of
poultry

4. A distinguishing characteristic of
the class Aves is the modification of
the jaws into a beak, the shape of
which is adapted to the foraging
behaviors and diet of individual
species. Gallinaceous birds have
pointed beaks for picking
up individual food items,

5. the tongue lacks
musculature and is not much more than a bone
(entoglossal bone) covered with a thick, cornified
mucous membrane.

6. The pharyngeal floor is characterized by a
raised laryngeal mound, which features the
aditus laryngeus (laryngeal slit). The opening
into the esophagus is caudal and somewhat
dorsal to this.

7. Within the neck, the esophagus
features a distensible dilation called the crop or
ingluvies. It is a small fusiform enlargement in
ducks and geese, but is extremely well developed in
gallinaceous birds.

8. In these birds, the
crop lies on the left side of the neck
cranial to the furcula, and when full
of food, it is readily
palpable and visible.

9. Like the esophagus, the
crop is lined by a keratinized stratified squamous epithelium.
Within the body cavity
the esophagus leads
to a bipartite stomach.
The first chamber is the
proventriculus or glandular stomach
provides pepsin and hydrochloric
acid for enzymatic digestion.

10. The proventriculus is demarcated
clearly by a constriction from the
second chamber, the gizzard
(muscular stomach or ventriculus
muscularis).
It largely fills the lower
left of the body cavity.

11. The highly keratinized mucosa on
the inside of the gizzard,
the cuticle
forms a thick,
leathery sheet
which is removed
during processing for human
consumption

12. Crops and gizzards are unique to
avian
digestive systems and contribute to
the efficiency with which many
wild and domestic
birds can utilize whole, intact
seeds, including grains, as part of
their diet.

13. The crop provides
for temporary storage after
swallowing
and
the gizzard provides a muscular
force to grind
and crush foodstuffs so that they
can be more effectively digested.

14. Hard particles, such as grit or
gravel, consumed with food
contribute to the ability of the
gizzard to properly grind intact
seeds, and a source of such
particles should be part of the diet
of birds fed this diet.
Grit is not necessary for diets
that are finely ground or in mash
form.

15. Neither the crop nor the gizzard
secretes enzymes to contribute to
enzymatic digestion
of foodstuffs.

16. The duodenum forms a distinctive
loop with the
pancreas sandwiched between
descending and ascending parts.

17. The pancreas communicates
with the lumen of the ascending
duodenum through three ducts in
gallinaceous birds and usually via
two (sometimes three) in
Anseriformes.

18. The ascending limb of the duodenum also receives the
two bile ducts.
These carry bile
from the liver directly (the hepatoenteric duct)
and
from the gall bladder (the cysticoenteric duct).

19. he liver of domestic birds consists
of
two lobes
simply referred to
as the right and left lobes.
These lie in the ventral body cavity
against the sternum and body wall

20. Foie gras (literally fat liver in
French, pronounced fwah′ grah) is
a food product made from the liver
of ducks or geese. It has been made
uniquely creamy and (to some
palates)

21. delicious by the forced-feeding of the bird
on corn. Because of the role of the liver in
digestion, this force-feeding results in
accumulation of fat in the liver, which
becomes
markedly enlarged as a result. The production
of foie gras is controversial, as many
people perceive that the practice produces a
state of ill health for the birds, and the force-
feeding technique may result in injury or
death of the bird.

22. the longest segment of the small intestine
is the jejunum. In many adult domestic
birds, the jejunum retains a remnant
of the embryonic connection to the yolk
sac Meckel’s diverticulum, which assumes
an immune function after retraction of the
yolk sac before hatching.

23. The short ileum terminates at the
large intestine, a point demarcated
clearly in domestic
birds by the presence of paired
ceca. These blind-ended diverticula
of the colon are
10–25 cm in ducks, chickens, and
turkeys,
and
22–34 cm in geese.

24. The paired ceca of domestic
birds and wild birds that eat seeds
(granivores)
provide a site for the digestion of
fiber by microorganisms.
The resulting volatile fatty acids
are absorbed from the ceca.
Cecal digestion is of little
importance in domestic fowl fed
highly digestible feeds.

25. The colon itself is relatively short
and straight, terminating at a
sphincter interposed between the
large intestine and the cloaca
an expanded region that is
common to the gastrointestinal and
urogenital tracts.

26. The cloaca is partially divided into three
named portions by encircling ring folds of
muscle covered with mucosa. Receiving
the terminus of the colon is the
coprodeum, a dilated
region that temporarily holds feces. It is
divided
by a ring fold from the next compartment,
the urodeum. The urodeum features the
openings of the two ureters in the dorsal
aspect of the lumen.

27. Just lateral to these are openings for
the seminal ducts in male animals.
In most female domestic birds, only
the left oviduct persists in
development, and this oviduct
opens lateral to the left ureter.

28. oviduct
refers to the entire tubular portion of
the female reproductive tract in birds.

29. the last portion of the cloaca is the
proctodeum. The unpaired bursa of Fabricius
(cloacal bursa) opens into the dorsal aspect
of the proctodeum. This bursa (for which the
B-cells of the immune system are named) is
lined by lymphoreticular tissue and is largest
in the juvenile animal, gradually becoming
smaller as the bird ages.
In Anseriformes, the proctodeum also
houses the male copulatory organ.

30. The anus of the bird is often
referred to as the vent. It presents
as a horizontally oriented
slit on the exterior of the body

31. Anseriformes
have a flattened, spoon-shaped beak that is
somewhat more flexible and is adapted for
straining through water for foodstuffs.
Beaks are featherless,