Download UDC 591.43+577.1:598 ANATOMIC AND MACRO

UDC 591.43+577.1:598
ANATOMIC AND MACRO-MICROMORPHOLOGIC STRUCTURE OF
DIGESTIVE TRACT OF WADERS AS LONG-DISTANCE MIGRANTS
Kharchenko L.P., Lykova I.О.
Н.S. Skovoroda Kharkiv National Pedagogical University
Waders are the distant migrants, the model object for researching of adaptation.
Longtime migrations and short time migratory stops requires from Waders the certain
compensatory mechanisms, that would optimize the accumulation of fat reserves
before migration period and during migration stops and also minimize energy
expenditure during the migration.
The characteristic of gastrointestinal tract of birds is a shortening of the
intestine, as one way of adaptation to the migration.
The relevance of this research is determined by fragmentation study of
gastrointestinal system of waders, as long distant migrants, mainly on the descriptive
anatomical level.
The offering article devoted to the research of macro –microscopic structure of
Waders’ intestinal tract, as long distant migrants. The researching materials were
intestinal systems of 16 waders: Recurvirostra avosetta (Linnaeus, 1758),
Himantopus himantopus (Linnaeus, 1758), Tringa ochropus (Linnaeus, 1758), Tringa
glareola (Linnaeus, 1758), Tringa nebularia (Gunnerus, 1767), Tringa erythropus
(Pallas, 1764), Tringa stagnatilis (Bechstein, 1803), Tringa totanus (Linnaeus, 1758),
Actitis hypoleucos (Linnaeus, 1758), Philomachus pugnax (Linnaeus, 1758), Calidris
minuta (Leisler, 1812), Calidris temminckii (Leisler, 1812), Calidris ferruginea
(Pontoppidan, 1763), Calidris alpina (Linnaeus, 1758), Limicola falcinellus
(Pontoppidan, 1763), Gallinago gallinago (Linnaeus, 1758), that were collected in
expeditions to the Azov-Black Sea region during 2011-2013 years.
Were researched the morphometric parameters of all parts of the intestinal, the
dependence of morphometric parameters on the size and weight of birds were
determined. The average weight of intestinal system of all kinds of birds which were
researched is 8,97 – 16,44 % of total weight of birds’ bodies.
The studied birds have thin, long and narrow tongue that has the deep groove
shape. It serves for swallowing of food and moving it from pharynx to esophagus.
The esophagus of studied birds has a small diameter of clearance, because of
waders mainly feed a small spineless. The length of esophagus depends on the length
of bird’s neck and makes 10-15% of total length of intestinal tract. The expansion in
the shape of goiter was founded in the esophagus Ph. pugnax.
The topography of mucosa membrane has a corrugated and creased surface that
determines its ability to stretch. Structurally, the esophagus’s creases are solid and
longitudinal. The shape of creases and topography of mucosa varies along the
esophagus. The creases in the cranial section are unbranched, round or ribbed shape
in the following kinds of birds: (Ph. pugnax, T. ochropus, T. glareola, T. nebularia,
T. stagnatilis, T. totanus, C. minuta, C. ferruginea, G. gallinago) other kinds (R.
avosetta, A. hypoleucos, C. аlpinа, L. falcinellus) – have sinuous round shape creases.
In the middle part of esophagus the sinuous creases save its shape, but meanders have
less marked form. The high and width of creases are unchanged, compared to the
cranial sector. The topography of creases’ surface almost unchanged in the caudal
sector in the following kinds: G. gallinago, T. stagnatilis, T. glareola, T. erythropus,,
other kinds: (R. Avosetta, T. nebularia, C. ferruginea) – observed the abrupt change
of creases’ shape. In the caudal sector of esophagus, where clearance is extending at
the entrance to the ferruginous stomach, the creases are creating the meanders at all
studied birds.
Investigation of the mucosal surface of the esophagus showed, that at the
waders observed relatively weak keratinization of the epithelium of the esophagus,
that compensate by significant development of the ferruginous apparatus, which
secretion perform the function as wetting of food, moving it along the esophagus, and
also mechanical save.
Studied birds have two-chambered stomach which consists of two sectors:
ferruginous and muscular. Average weight of stomach of C. Minuta ranges from 0,95
g - , weight of stomach Ph. pugnax above 12,7 g.
Ferruginous stomach has a spindle shape and it is 0,1% – 0,5% of the total
weight of bird, the thickness of stomach wall is – 0,7-2,0 mm. The food passes
through the esophagus to the ferruginous stomach like transit, almost without
stopping. The gastric fluid, that exuded by complex deep glands of ferruginous
stomach, reach the muscular stomach together with food, where main process of
mechanical and chemical processing of food take place.
Investigation of mucosa of ferruginous stomach showed that its characteristic is
creasesing and holes of output channels of different diameter. The mucosa of
ferruginous stomach is creates the plates around the holes of output channels. The
shape and high of plates is variable in different kinds of studied birds.
The muscular stomach has ellipse shape at all studied birds. The weight of
muscular stomach to the total weight of body is 7,5 - 10,8%. The walls of muscular
stomach are good developed, its thickness is 4,5 mm (C. minuta) – 15 mm (Ph.
pugnax).
There are blind bags on the opposite sides of the muscular stomach. The relief
of mucosa of the muscular stomach is represented by longitudinal creases. Mucosa
of muscular stomach covered by strong cuticle, its thickness is 0,2 – 0,3 mm, in the
cavity of muscular stomach found gastroliths (gravel, sand, mussels of mollusks).
Thick walls of muscular stomach together with gastroliths and strong cuticle provide
mechanical shredding of solid feed components.
The results of morphometric researching of waders’ intestine showed, that for
most birds the shortened intestine is typical, and it length is in 2,2-4,8 times longer
than body. The cyclic location of intestine loops in the abdomen of waders
determines the compact location near the center of body weight, it is provides the
aerodynamic of birds. Above feature are important for waders as long distant
migrants.
The diameter of stomach clearance is varies along the length of digestive tube
and reach the largest diameter in the ileum sector, the smallest diameter of clearance
have a blind and rectum.
Small intestine consists of duodenum, empty and ileum. For all studied birds
typical the lamellar relief of the mucous membrane of the small intestine. The plates
of mucosa make complex labyrinth system, where chyme and ezymes can be delay in
the cavities.
Different kinds of waders have a variable location and shape of plates. The
research results of architectonic relief of small intestine allow to identify three types
of plate relief: the wedge shaped plates with sharp edge (T. ochropus, T. erythropus,
T. stagnatilis); pyramidal shaped plates with smooth edge (T. nebularia, T. glareola,
G. gallinago, A. hypoleucos); shovel shaped plates with rounded edge, which locating
at the angle of 800–900 to each other, and forming zigzag labyrinths. (C. alpina, C.
ferruginea, C. temminckii, C. minuta, Ph. pugnax, R. avosetta, L. falcinellus).
At all studied birds was noted the reduction of size and density of location
plates of the mucous membrane of the small intestine, creation of zigzag labyrinths in
the caudal direction of the intestine
We found Meckel’s diverticulum on the unti-misenteric surface of blank
intestine’s loop at all studied kinds of Waders that is a residue of the vitelline duct.
The Meckel’s diverticulum of all kinds of waders is the tubular body, its length from
4,8 mm (C. minuta) to 18,5 mm (Ph. pugnax), diameter is 2,1–4,2 mm, its shape like
blind appendix, the top directed cranially and connected with wall of blank intestine
by connective elements. Diverticulum consists of base, middle and apex parts. The
relief of mucosa of Meckel’s diverticulum in the base part is lamellar, in the middle
and apex part of the diverticulum the mucosa has soft homogeneous structure.
The results of morphomentric parameters of the small intestine and
architectonics of mucosa relief that we found, allow to assert, that digestive and
nutrients absorption processes occurring along the small intestine. Zigzag location of
plates helps to delay the digestive enzymes in the small intestine, it is prolongs its
contact with chyme and thus increases the efficiency of the digestive system in the
short intestine of Waders. This feature is very important for Waders as long distant
migrants, especially during the migration stops, when the time for searching the food
and replenish the body’s energy reserves is limited.
The results of researching the topography of rectal mucosa showed that mucosa
of all studied kinds of Waders have the longitudinal creases.
The relief along the whole length of rectal mucosa is complicated by plates,
which functionally increase the absorption surface. We have indentified three kinds
of rectal mucosa relief in studied kinds of Waders: 1) mucosa with well-defined
creases and plates between them, which located at the angle of 45-50 о to the creases.
(Ph. pugnax, G. gallinago, A. hypoleucos); 2) mucosa with moderate creases and
plates, which located throughout the surface at the angle of 65-70о to the creases (T.
ochropus, T. erythropus, T. stagnatilis, T. glareola, T. nebularia, R. avosetta); 3)
mucosa with weakly expressed crease and plates that are densely located over the
whole surface of mucosa (C. alpina, C. ferruginea, C. temminckii, C. minuta, L.
falcinellus).
In the part where small intestine transfers into large one all studied Waders
have paired cecums. At the most of studied kinds of Waders the caeca makes 11-19%
of total length of intestine. So, the largest sizes of cecums were seen at C. alpina –
18,2%, the smallest – at G. gallinago – 11,2% of the total length of the intestine. The
insignificant sizes of cecums has T. еrythropus (4,6% of total length of intestine),
almost reduced has T. glareola (2,1%) і T. nebularia (0,7%).
The cecums of Waders are the lymphoid-epithelial body, as demonstrated by
the histological studies (Kharchenko, Lykova, 2013). The research of shell cecums
relief showed that relief of mucosa is heterogeneous. The lamellar relief remains in
the neck part, in the body and the top part the plates are almost absent.
The liver of studied kinds of waders consists of two parts: left part is
considerable smaller that right. The weight of liver is 2,77 – 5,27% of total weight
of bird’s body. The pancreas of studied kinds of Waders locate in the loop of the
duodenum, and its weight is 0,35 – 0,73 % of total weight of bird’s body.