Bird Reproduction L20 | Physiology 2 Exam 3

With bird reproduction, what are the signs of well-defined estrous and pregnancy

no well-defined estrous nor pregnancy

What are the two commercially relevant breeds of hens that related to bird repro

• hens laying 250-270 eggs per year

• hens that lost their brooding drive

How does photoperiod play a role in reproductive activity of birds

releases melatonin to stimulate hypothalamic photoreceptors

What are the steps of photoperiod activation of hypothalumus to release hormones

1. light inc stimulates hypothalamic photoreceptor

2. activates hypothalmic neurons to release GnRH granules

3. → activates pituitary gonadotropes to release FSH, LH

4. → stimulating the release of progesterone, androgens and estrogens

In avian reproduction, hypothalamic photoreceptors release progesterone which stimulates what

F1 preovulatory follicle

In avian reproduction, hypothalamic photoreceptors release androgens and estrogens which stimulates what

small ovarian follicles

Where are male testes located in bird repro

near the cephalic end ventrally of kidneys

In bird repro, how is sperm conducted to cloaca

epipdidymis and ductus deferens conduct sperm to cloaca

What is the end of ductus deferens referred to as

seminal glomus

What is the male bird’s pseudopenis called

phallus

Where is yolk produced under (what hormone)

produced in liver

under estradiol influence

What are the main components of yolk

• lipoproteins (VLDL)

• vitelogenin

What is the step-by-step mechanism of transport of yolk components

1. from liver → storage of lipoproteins w/in perlecan theca membrane

2. binding to gallus gallus basement membrane protein (ggBM1) transferring lipoproteins

3. Diffusion through gap junctions of granulosa cells and through zona pellucida

4. binding to lipoprotein receptor 8 (LR8) at oocyte surface

In birds, what is the difference between GnRH-I and GnRH-II

• GnRH-I more relevant in vivo

• GnRH-II more potent in stimulating LH release in vitro

What is the purpose of GnRH-I in bird reproduction

more relevant in vivo

What is the purpose of GnRH-II in bird reproduction

GnRH-II more potent in stimulating LH release in vitro

What is LH surge in birds induced by and when is it induced

LH surge in birds induced by progesterone

4-6h before ovulation

In ovary of hen, how do follicles develop and what do follicles not contain

follicles develop in sequence

Do not contain antrum

What does it mean to have F1 and F2 in hen’s ovary

F1 is the largest follicle to ovulate w/ F2 being next and continues sequence

What does the hen’s ovary contains

• follicles (following sequence)

• post-ovulatory follicles

• small yellow follicles

• germinal disc

What is the time between ovulations of hens

24hr

In hens, where do reproductive organs develop

only on the left side

In hens, which ovary produces eggs in birds reproduction

left ovary

What are the reproductive organs of birds

• ovary

• oviduct

  1. infundibulum

  2. magnum

  3. isthmus

  4. shell gland (uterus)

  5. vagina

• cloaca

What are the structures of the oviduct in bird reproductive system

oviduct

• infundibulum

• magnum

• isthmus

• shell gland

• vagina

In the oviduct, what is the process of oocyte transport to egg expulsion

1. infundibulum - transport of oocyte down oviduct

2. magnum - formation of albumen

3. isthmus - formation of outer and inner shell membranes

4. shell gland - formation of shell

5. vagina - transports egg to cloaca

What is the purpose of infundibulum in bird repro and the time duration of process

infundibulum - transport of oocyte down oviduct ,15 min

What is the purpose of magnum in bird repro and the time duration of process

magnum - formation of albumen, egg white, 3h

What is the purpose of isthmus in bird repro and the time duration of process

isthmus - formation of outer and inner shell membranes, 1.5 h

What is the purpose of shell gland in bird repro and the time duration of process

shell gland - formation of shell, 20 h

What is the purpose of vagina in bird repro and the time duration of process

• maintains reservoir of spermatozoa, lasts 2-3weeks

• egg transport to cloaca

In the shell gland, what component makes up the shell

calcium carbonate

What is the yolk composition of a hen’s egg in bird repro

• 36% lipids

• 17% protein

• (the rest 47%) vitamins and water

What is the albumen composition of a hen’s egg in bird repro

• 84-89% water

• 10-11% protein

• rest small amounts of carbohydrates, lipids, and minerals

What lipid components are in yolk of hen’s egg

lipids in yolk contain:

• 70% triacylgylcerols

• 25% phospholipids

• 5% cholesterol

What is the protein components are in albumen of hen’s egg

proteins in albumen contain:

• ovalbumin 54%

• ovotransferrin 13%

• ovomucoid 11%

• ovoglobulins 8%

• lysozyme 3.5%

• ovomucin 1.5-3%

Comparing the composition of yolk and albumen in hen’s eggs, which have a higher protein concentration

yolk - 17%

Comparing the composition of yolk and albumen in hen’s eggs, which have a higher lipid concentration

yolk - 36%

Comparing the composition of yolk and albumen in hen’s eggs, which have a higher water concentration

albumen - >80%

Comparing the composition of yolk and albumen in hen’s eggs, which have a minerals and which have vitamin concentration

yolk - vitamin

albumen - minerals

What are the layers of hen’s preovulatory follicle

PGTTLS

1. perivitelline layer

2. granulosa layer

3. theca interna

4. theca externa

5. loose CT w/ SM

6. superficial epithelium