Exam 2 Flashcards
chickens are a prey species. what characteristics of their reproduction do they have to support their life as a prey species?
- need ability to still fly
- many offspring requiring little care
- all nutrients in the egg
why would laying eggs help a chickens ability to fly?
the weight of the chick does not weigh the chicken down
precocial
born self sufficient (they are able to care for themselves)
altricial
born helpless (think naked baby birds screaming for their mother)
clutch
number of eggs laid in succession (how many days in a row the bird lays an egg)
different poultry _______ will vary on clutch length, for example the road island red has a very long clutch ranging up to about 15 days
breed
a prey species will want to produce a lot of offspring because they expect about ___% of the chicks will die (whether in production or with the hen herself)
1 %
two parts of the female reproductive tract
- ovary
- oviduct
hens are born with 2 ovaries and oviducts but only 1 will develop as they sexually mature, typically the _____ side will develop
left
is it possible for the right ovary and oviduct to develop?
yes! there are some cases where the left side is damaged so the right side develops instead
the purpose of the ovary is to develop _________
oocytes
T or F: the ovary is formed at birth, meaning that it has to mature with the bird
true
what is the stigma?
lack of vasculature on the yolk, where the follicle will burst through in ovulation
what are these arrows pointing to?
the stigma
infundibulum
the muscular structure that catches and guides the released eggs to the oviduct, also the site of fertilization
magnum
the largest portion of the oviduct, the thick albumin is deposited here
isthmus
the inner and outer shell membrane are formed
shell gland / uterus
makes the shell
to form the shell the body uses ____% of calcium from body stores and over ____ of the calcium from the diet
8-10%; half
vagina
where the bloom / cuticle is applied
bloom / cuticle
the covering of the shell (waxy/oily) that protects it from environmental contaminants
an egg can be left out for _____ days IF it has the bloom/cuticle still on it
10-15 days
sperm host glands
stores sperm
what is the purpose of the sperm host glands?
the bird can store sperm for a long period of time, so they do not have to mate as often which is important as a prey species
how are birds eggs fertilized using the sperm host glands?
pushing the egg out will release sperm and it will then travel towards the infundibulum to fertilize the egg
be able to label the female reproductive tract!
how long is the infundibulum? how much time does the formation of the egg take there?
- 3-4 inches
- 15-16 minutes
how long is the magnum? how much time does the formation of the egg take there?
- 13 inches
- 3 hours
which area of the female reproductive tract does the egg spend a majority of its time developing?
shell gland / uterus
how long is the isthmus? how much time does the formation of the egg take there?
- 4 inches
- 75 minutes
how long is the shell gland / uterus? how much time does the formation of the egg take there?
- 4-5 inches
- 20 hours
how long is the vagina?
4-5 inches
what are the parts on the male reproductive tract?
- testes
- vas deferens
- cloaca
- vent
in the bird the testes are _______, located near the kidneys. this is different than most species.
internally (inside the body cavity)
vas deferens
carry the sperm from the testes to outside of the body
capoization
castration of the male bird
when should a bird be castrated? why?
it should be done when they are very young because the testes will grow closer to the kidneys as they age, the procedure becomes more dangerous
a capon grows at a _______ rate than a rooster producing a softer and moister product
slower
be able to label the male reproductive tract
due to photosensitivity in poultry they are _____-day breeders
long-day breeders (>12 hours of light)
HPG axis
hypothyroid pituitary gonaditary axis
what is the significance of the HPG axis in poultry?
these parts in the hypothyroid pituitary gonaditary axis work together as a crucial neuroendocrine system regulating reproductive functions, including egg production and fertility, by coordinating the hypothalamus, pituitary gland, and gonads through hormone signaling
when does change in gonadal size occur?
the gonads will get larger as the birds get older but they ALSO can get larger during the breeding season
when is the typical breeding season for poultry?
summer! (long days, more light)
why is the thyroid hormone also important to photosensitivity in poultry?
it regulates the seasonal component in reproduction, effects GnRH levels
for fertilization, which species/industry uses artificial insemination?
turkeys
for fertilization, which species/industry often uses natural insemination?
chickens
what time are turkeys artificially inseminated? why?
after 3pm so that the sperm is ready to be utilized with the egg is laid
T or F: it is common to freeze poultry semen
FALSE, we use a fresh seme dose, poultry semen does well for about 30 minutes in room temperature and extender can make it last 24 hours, there is not a really great way to freeze the semen
what effects fertility in birds?
- mating frequency
- age
- diet and body weight
- environment (temperature)
- semen handling and processing
what is milking in context of poultry reproduction?
collecting sperm in male birds
why do turkeys struggle to naturally mate?
breast size, sharp nails, more aggressive, etc.
poultry has a __________ curve of fertility
parabolic (not very fertile when they are young and not very fertile when they are old)
roosters can have ________ meaning that they want to breed some hens more than others
favoritism
what does a mating “dance” look like in birds?
the male will drop one wing and walk around the hen, then the hen will squat and the rooster will sit on her back, then they will have cloaca contact
T or F: when poultry mate, they touch vents
FALSE, they are NOT vent to vent, they are cloaca to cloaca (often called the cloacal kiss)
_______ size is often indicative of testes size
comb (the larger the comb, the larger the testes)
when is the most mating done for poultry?
most mating down during daylight
why is the physical condition of the birds important to mating behavior? how are body weight, breast size, feet, and legs important?
if they weigh too much or their breasts are too big they can have difficulty mating. if they’re legs and feet are not strong enough to move and support their weight they may not be able to mate.
pecking order
a social structure where individuals establish a hierarchy within a flock, with dominant birds having priority access to resources and mates
for every 10 hens there should be ____ rooster to ensure all are able to be bred
1
why do we rotate the eggs side to side during incubation?
to ensure that the chick doesn’t stick to one side, important to development
chalaza
a spiral structured tissue within the egg that anchors the yolk/chick in the center of the egg
germinal disc / blastoderm
where the chick develops from
vitelline membrane
a semipermeable membrane that surrounds the yolk of an egg and separates it from the egg white. helps protect the yolk
the ______ is the primary source of nutrients as the chick is developing
yolk
be able to label the eggs anatomy
which direction is the egg laid? which way is the egg incubated?
Eggs are typically laid with the blunt (larger) end first, and for incubation, eggs are often placed with the pointed (smaller) end down to make the air cell on the top
how long does it take for a chick to fully develop in the egg?
21 days
phase 1 of embryonic development
occurs in the hen, chalaza holds the blastoderm, there is division and growth of cells (isthmus has 2-4 cell, uterus has 16 cell stage), gastrulation occurs
gastrulation
segregation of cells for specialized functions
what is the purpose of egg breakout?
opening the egg up at different stages of development
what is a good sign that the germ cells begin the differentiate in the egg?
primitive streak (crevace)
T or F: we can store the eggs and cause developmental pauses
true
eggs are stored at _______ degrees and _______% humidity
55-67 degrees and 75-80% humidity
> _____ days decrease hatchability
14
what is physiological zero?
the temperature below which embryonic development is arrested, meaning embryonic cell activity is greatly reduced but reversible, and development restarts when temperatures rise above this point
the longer that we store eggs the ________ the temperature should be
lower
SPIDES
Short Period Incubation During Egg Storage
what are the three major benefits of using the SPIDES method?
- increase hatchability in eggs
- increase chick quality
- decrease hatch window
what is the purpose of decreasing the hatch window?
birds hatch close to the same time, we want this to occur because we are moving these birds at the same time so we want to pull everyone at the same time
what is SPIDES?
SPIDES, or Short Periods of Incubation During Egg Storage, is a hatchery practice that involves briefly warming eggs to a specific temperature (between 35°C and 37.8°C) before cooling them, repeated weekly, to improve hatchability, especially when eggs are stored for longer periods
during embryonic development, we want the air cell facing ____
up
what are the extra embryonic membranes?
- amnion
- yolk sac
- allantois
- chorion
- air cell
what is the purpose of the amnion?
prevent dehydration
what is the purpose of the air cell?
provides air for the chick (also some gas exchange across the cell)
day 1 of embryonic development
- alimentary tract
- vertebral column
- nervous system
- head
- eye
day 2 of embryonic development
- beginning of heart
- ear formation
- heartbeat
day 3 of embryonic development
- nose
- wings
- legs
within ____ hours the chick looks like a microscopic chicken
16
day 4 of embryonic development
tongue
day 5 of embryonic development
reproductive organs and sex differentiation
day 6 of embryonic development
beak forming
week 2 of embryonic development
- day 8 = feathers
- day 10 = hardening of beak
- day 13 = scales and claws
- day 4 = positioning for hatching
what is the positioning for hatching?
head moves up toward the air cell so they are able to pip out of the cell
week 3 of embryonic development
- day 16 = scales, claws, beak hardening
- day 17 = beak turns toward air cell
- day 19 = yolk sac absorption begins
- day 20 = yolk sac absorbed, embryo fills egg with exception of air cell
- day 21 = hatch!!
what day should the eggs be moved from the incubator to the hatcher?
day 19
_____ causes the chick to hatch
stress
chickens take ___ days to develop and hatch
21
turkeys and guineas take _____ days to develop and hatch
28 days
quail take ___ days to develop and hatch
19-24 days
ostrich takes ___ days to develop and hatch
42 days
why would chicks and embryos communicate around hatching?
they communicate the fate of hatch, so they can hatch together
what happens to eggs that are not hatched on the same day as all of the other chicks?
they are euthanized
what does candling mean? what is the purpose?
to be able to determine the quality of the egg (check the viability of the chick inside, look for deformities)
T or F: candling is a highly automated process that uses computers to sense if the eggs are viable
true!
the incubator is kept at about _______ degrees F and _____% relative humidity
98.6 - 100 degrees F; 60%
T or F: it is better to have lower humidity than higher humidity in the incubator because high humidity can give malformations
true!
T or F: ventilation is important during incubation to control the amount of CO2 and heat
true!
how long are chicks kept in the incubator?
18 days
what is the difference between a single stage and multistage incubator?
- single stage means that all the chicks are the same age and go in at the same time
- multistage has multiple ages of eggs in the incubator at one time, the youngest goes in and pushed down the older eggs keeping them grouped together
why does airflow matter in a multistage incubator?
the older, larger birds produce more heat, so we can use this heat to warm the younger birds
when do the eggs get moved into the hatcher?
day 19
as the eggs are moved into the hatcher, why are they candled?
so ensure there are viable chicks, and remove infertile eggs
in the hatcher the temperature is _____ degrees F with _____% relative humidity
98.6-100 degrees F; 65-70%
T or F: in the hatcher the chicks need to be turned
FALSE; no turning is needed, the chicks should be developed enough not to stick to anything (air cell needs to be up)
what is in ovo vaccination?
in the hatcher, the eggs are vaccinated while still in the egg
why should we pull the basket when most chicks are hatched?
to avoid dehydration
what effects hatching time?
- parent flock age
- storage time
- egg size
- hatching conditions
small eggs have ___ shells and ____ pores
thick; small
large eggs have ____ shells and _____ pores
thin; large
pipping
when a young bird cracks over the egg when hatching
what is a straight crack vs badly pipped during hatching?
we want a straight crack during hatching because that means the chick with strong enough to open the egg, a body pipped shell means that the chick had to work really hard meaning it could be in poor conditions
how to calculate hatchability
hatched / set
chick yield
chick weight as the percentage of initial egg weight
what effects hatchability and chick yield?
- age of breeders
- egg size
- fertility
- eggshell
what is the separator room?
where the chicks are separated from their egg shells, the vacuum sucks in the shells where they are then rendered, unhatched eggs are euthanized
T or F: in the separator room all chicks are inspected by hand
true! dead chicks are collected and chicks that may be culled are collected at this time
why would a chick be culled in the separator room?
- unhealed navel
- poor down
- nutritional disorders
- malformations
what physical deformity is caused by a nutritional disorder where the chick is lacking vitamin D?
soft bones
what physical sign may a chick show with a nutritional disorder where the chick is lacking vitamin B12?
short beak
in the separator room the chicks are counted into groups of _____
100
how do spray vaccines work?
chicks are sprayed with the vaccine and as they preen themselves they will ingest the vaccine
what occurs at the chick processing table?
- beak trimming
- toe trimmin
- vaccination (loose skin neck)
- split sex
how can you sex chicks?
using feather length, females will have longer feathers due to estrogen while males have shorter feathers
which chick is the male? which is the female?
- left = female
- right = male
when the chicks are traveling to the farm when environmental controls should the truck have?
maintain temperature and ventilation
what is a gel pod?
used during chick travel, it serves as both moisture and food to keep the chicks hydrated
__________ chicks per day are traveling to farms
100,000
what are the three things that make primary breeders different?
- biosecurity
- genetic selection
- international trade
what are two major primary breeder companies?
Aviagen and Cobb (Tyson)
what is the product development pyramid in poultry production?
top
- pedigree
- GGP
- GP
- PS
- broilers
bottom
which sectors of product development are considered to be at the primary breeding level?
- pedigree
- GGP
- GP
it takes ___ years for genetics changes to be seen by consumers
5
today we look at over ____ different traits for genetic selection criteria
40
how can pedigree companies track individual birds to create statistical models?
every pedigree bird can be microchipped and scanned at every life stage
why is it important to measure the FCR of the birds over their lifespan?
feed costs are 60-70% of total costs of raising birds
what does sustainability have to do with poultry production?
by improving FCR the chickens need less feed which means there is less acreage for production so less water used etc. As bird performance improves there is a good impact on the environment
many of the hatcheries in the US are located in close proximity with _________ so the birds can travel internationally
airports
what are important aspects of biosecurity for a primary breeder?
- solid walls, concrete
- geography
- litter
- feed
- people
- equipment
- rodents
- water
T or F: feed mills for primary breeders are shower in and shower out facilities
true
the old fashioned approach was that primary breeders would have multiple barns on the same property with different generations. How has this changed today and why?
today there are 2 to 5 house sites that are spaced out, this is so if one barn gets sick it is unlikely to get all of the birds sick causing the company to crash
PS
parent stock
what is a primary breeder?
Breeding birds whose offspring are used as breeding birds. These include pedigree (elite/foundation), great-grandparent, and grandparent flocks
class
geographic area (ex: Mediterranean, English, American)
breed
within a class
variety
within a breed, color
strain
different genetics (ex: Ross 308)
nicking
a poultry term for hybrid vigor / heterosis
different organisms have a different number of chromosomes. chickens have ___ pairs and turkeys have ___ pairs.
39; 40
ZW - male or female?
female
ZZ - male or female?
male
does the male or female determine the sex of the offspring?
the female
why would the males being homozygous (ZZ) for their sex chromosomes be problematic for the poultry industry?
you are unable to sex sort semen
what is the name of the wildtype chicken that originated from Southeast Asia?
gallus gallus
when the gallus gallus were domesticated, what were the breeds that came out of it?
- white leghorn
- Rhode Island reds
- white Plymouth rock
- barred Plymouth Rock
- New Hampshire
- cornish
what domesticated chicken breed is considered a layer?
white leghorn
what domesticated chicken breed is considered a meat bird?
cornish
what domesticated chicken breed is considered a dual purpose bird?
- Rhode Island red
- white Plymouth rock
- barred Plymouth rock
- new Hampshire
what breed is used as a broiler sire in commercialization ?
cornish
what breeds are used as broiler dams in commercialization?
- white Plymouth Rock
- barred Plymouth rock
- New Hampshire
what breeds are used as brown egg-layer in commercialization?
- Rhode Island red
- white Plymouth Rock
what breed is used as white egg layers in commercialization?
white leghorn
what is todays commercial broiler? why?
- cornish x white Plymouth Rock
- cornish is an English breed that has fast growth and muscular
- white Plymouth rocks are an American breed that are large, have good growth, and can produce eggs
who is Cecile Steele?
credited with pioneering the poultry industry in 1923. When Steele received an accidental shipment of 500 chicks for egg production instead of 50, she built additional housing and raised the birds, selling them for meat at $0.62 per pound
todays commercial layers
- single comb white leghorn
- single comb Rhode Island reds
this commercial chicken breed is used as a layer, Mediterranean (Italy), they are light and small with high egg production and flighty: ______ _______ ________ _________
single comb white leghorn
this commercial chicken breed is used as a layer, American, dual purpose bird, can be used in cage free systems because they are flightless: _______ _______ _______ _______ _____
single comb Rhode Island reds
todays commercial turkeys
- broad breasted bronze
- broad breasted white
this turkey breed is a heritage breed that can naturally breed, has slow growth and a lower lifespan: ________ _________ _________
broad breasted bronze
this turkey breed has been selected to pluck easier and have increased breast size but they are unable to breed naturally: ________ ________ _______
broad breasted white
colors, patterns and feather types, comb types and skin color are considered _________ inheritance
simple
patterns/coloring, feather growth rate, and dwarfism are considered __________ inheritance
sex-linked
commercially relevant traits (including welfare, breeder qualities, broiler qualities, and processing qualities) are considered __________ traits
polygenic
what are the 4 goals of commercial relevant traits
- welfare
- breeder quality
- broiler quality
- processing quality
what is heritability?
the likelihood of a trait being passed from parent to offspring
______ heritability is <19% and includes reproduction traits
low
________ heritability is 20-39%
moderate
_______ heritability is >40% and includes growth traits
high
what broiler traits have high heritablility?
- 8 –week broiler weight 45%
- Total feed consumption 40%
- Fat deposition 50%
what broiler traits have low heritability?
breast fleshing 10%
what layer traits have high heritablility?
- Adult body weight 55%
- Egg weight 55%
- Egg shape 60%
what layer traits have low heritablility?
- Fertility 5%
- Blood spots 15%
the heritability for boilers: 8-week broiler weight ___%
45%
the heritability for boilers: total feed consumption ___%
40%
the heritability for boilers: fat deposition ___%
50%
the heritability for boilers: breast fleshing ___%
10%
the heritability for layers: adult body weight ____%
55%
the heritability for layers: egg weight ___%
55%
the heritability for layers: egg shape ____%
60%
the heritability for layers: fertility ___%
5%
the heritability for layers: blood spots ___%
15%
genetics companies in the poultry industry
- AVIAGEN
- Cobb-Vantress (Tyson)
- AVIAGEN Turkey
- Hybrid
- Hy-Line
draw out the pyramid of the poultry industry
what are the poultry industries main goals?
- promote welfare, health and productivity
- preservation of self is most important
how to maintain/improve health
- sanitation
- biosecurity
- vaccination
- medication
- vector control
- management
two types of immune systems
- innate
- adaptive
innate immune systems
the body’s first line of defense against pathogens and other harmful substances. It is a non-specific, immediate response that is present at birth and does not require prior exposure to a specific pathogen
adaptive immune system
a complex and highly specific defense mechanism that protects the body from pathogens and other harmful substances, it is from the body’s memory (like from vaccinations or past illness)
macrophages
Macrophages present antigens (foreign substances) to T cells, initiating an adaptive immune response. They also secrete cytokines, which regulate inflammation and immune cell activation
immune organs
- bursa
- spleen
- thymus
- bone marrow
- cecal tonsils
- Peyer’s patches
the bursa produces _____ cells for immune response
B
the thymus process ___ cells for immune response
T
these two immune organs are in the GI tract
- cecal tonsils
- Peyer’s patches
innate vs adaptive immunity
innate immunity is a rapid, non-specific defense system present from birth, acting as the body’s first line of defense, while adaptive immunity is a slower, specific defense system that develops throughout life, learning to recognize and remember specific pathogen
types of vaccinations
- live
- live attenuated
- killed
what are different routes of administration for vaccinations?
oral, injection, ocular (eyes), water, spray fog, in ovo
what are good ways to promote bird health?
- BIOSECURITY
- vaccinations
- prevent vectors
what are vectors?
organisms that carry disease and can spread it
examples of vectors
- wild birds
- rodents
- worms
- insects (mites, flies, fleas, lice, darkling beetles)
worms are transmitted by __________ _____
intermediate host
rodents are known for spreading __________
salmonella
what are darkling beetles?
they hang out around spilled feed and can carry avian influenza, Newcastle, etc.
highly pathogenic diseases
- marek’s
- Infectious Laryngotracheitis
- Infectious Bronchitis
- Newcastle Disease
- Avian Influenza
- Infectious Bursal Disease
- Fowl Pox
moderately pathogenic diseases
- coccidiosis
- necrotic enteritis
food safety diseases
- salmonella
- E.coli
- campylobacter
marek’s is considered a _______________ disease
highly pathogenic
infectious laryngotracheitis is considered a ______________ disease
highly pathogenic
infectious bronchitis is considered a ______________ disease
highly pathogenic
Newcastle disease is considered a ______________ disease
highly pathogenic
avian influenza is considered a ______________ disease
highly pathogenic
infectious bursal disease is considered a ______________ disease
highly pathogenic
fowl pox is considered a ______________ disease
highly pathogenic
coccidiosis is considered a ______________ disease
moderately pathogenic
necrotic enteritis is considered a ______________ disease
moderately pathogenic
salmonella is considered a ______________ disease
food safety
E. coli is considered a ______________ disease
food safety
campylobacter is considered a ______________ disease
food safety
WHAT DISEASE: disease of young chickens that is within the herpes virus group, concentrates in feather follicles, and aerosols. mortality can vary depending on the strain. there is a vaccination for it.
Marek’s Disease
describe marek’s disease
disease of young chickens that is within the herpes virus group, concentrates in feather follicles, and aerosols. mortality can vary depending on the strain. there is a vaccination for it.
WHAT DISEASE: it is a viral disease that is highly pathogenic that affects the respiratory system. birds are carriers for life. there is an effective vaccine that can be given as an eye drop, in water or as spray.
infectious laryngotracheitis (ILT)
describe infectious laryngotracheitis (ILT)
it is a viral disease that is highly pathogenic that affects the respiratory system. birds are carriers for life. there is an effective vaccine that can be given as an eye drop, in water or as spray.
WHAT DISEASE: an extremely contagious disease that only effects chickens. it is more problematic in the layer industry causing coughing, sneezing, “rales”/rattling, and small eggs with a soft shell and irregular shape
infectious bronchitis
describe infectious bronchitis
an extremely contagious disease that only effects chickens. it is more problematic in the layer industry causing coughing, sneezing, “rales”/rattling, and small eggs with a soft shell and irregular shape
what disease would cause eggs that look like this:
infectious bronchitis
WHAT DISEASE: this disease is a contagious viral infection that is transmitted by contaminated equipment, shoes, clothing, and free-flying birds. it causes respiratory symptoms and then nervous. mortality greatly varies. the most severe strain is not in the US. there is a vaccination for it.
Newcastle disease
describe Newcastle disease
this disease is a contagious viral infection that is transmitted by contaminated equipment, shoes, clothing, and free-flying birds. it causes respiratory symptoms and then nervous. mortality greatly varies. the most severe strain is not in the US. there is a vaccination for it.
WHAT DISEASE: a viral disease (Type A) that wild fowl are carriers for and highly contagious. There are various levels of symptoms, one of which is a drop in egg production. it is a zoonotic disease.
avian influenza
describe avian influenza
a viral disease (Type A) that wild fowl are carriers for and highly contagious. There are various levels of symptoms, one of which is a drop in egg production. it is a zoonotic disease.
WHAT DISEASE: a highly contagious disease found in young chickens that decreases their immune development. they can get the disease through direct contact transmission and contamination. symptoms include ruffled feathers, slight tremor, strained defecation and when forced to stand have an unsteady gait
gumboro (infectious bursal disease)
describe gumboro (infectious bursal disease)
a highly contagious disease found in young chickens that decreases their immune development. they can get the disease through direct contact transmission and contamination. symptoms include ruffled feathers, slight tremor, strained defecation and when forced to stand have an unsteady gait
WHAT DISEASE: a viral disease that infects both chickens and turkeys. transmission occurs via contact with skin abrasions and insects can be vectors. there are two forms, one called cutaneous where lesions are on unfeathered skin and the other is diphtheritic where the lesions on upper GI and respiratory systems. vaccination is the best control.
fowl pox
describe fowl pox
a viral disease that infects both chickens and turkeys. transmission occurs via contact with skin abrasions and insects can be vectors. there are two forms, one called cutaneous where lesions are on unfeathered skin and the other is diphtheritic where the lesions on upper GI and respiratory systems. vaccination is the best control.
cutaneous fowl pox
lesions on unfeathered skin
diphtheritic fowl pox
lesions on upper GI and respiratory systems
WHAT DISEASE: a protozoal disease that causes necrotic enteritis and bloody diarrhea. this is transferred by fecal-oral route. there is a vaccination for this disease to anti-coccidial drugs
coccidiosis
describe coccidiosis
a protozoal disease that causes necrotic enteritis and bloody diarrhea. this is transferred by fecal-oral route. there is a vaccination for this disease to anti-coccidial drugs
what are common food borne illnesses?
- salmonella
- E. coli
- campylobacter (campy)
- listeria
_________ is the #1 cause of food borne deaths
listeria
what food borne illness in a bacteria that lives in eggs?
salmonella
what temperature should poultry products be cooked to to prevent food borne illness?
165 degrees F
what food borne illness is a bacteria that lives in the gut of all species and is opportunistic?
E. coli
what food borne illness is a bacteria that usually doesn’t affect birds?
campylobacter (campy)
what is genetics?
the study of genes, genetic variation, and heredity of organisms
_________ is vital to organism’s evolution
heredity
describe the structure of DNA
- deoxyribose nucleic acid
- written 5’ to 3’
- double stranded
- hydrogen bonds
- linear polymer
- antiparallel and complementary
nucleosome
DNA + histone
central dogma
DNA –> RNA –> protein
what is a gene?
a unit of hereditary information
T or F: one gene = one protein
FALSE (there are many due to alternative splicing)
what is heredity?
the offspring cells or organisms acquire the genetic information of their parents (haploid + haploid = diploid)
is a variant of the sequence of nucleotides at a particular location (SNPs, indels)
allele
is a specific position on a chromosome where a particular gene or genetic marker is located
locus
homozygous
same alleles from both parents
heterozygous
different alleles from both parents
an organism’s genetic makeup, specifically the combination of alleles present at a particular locus in the genome
genotype
observable characteristics of an organism
phenotype
rate of crossover events is proportional to the ___________ between two genes
distance
genes on the same chromosome are “_________” and usually inherited together
linked
the _____________ allele is expressed over the other
dominant
the inheritance of a phenotype that is determined by a gene located on one of the sex chromosomes
sex-linked inheritance
incomplete dominance
dominant and recessive traits are mixed (ex: red and white make pink)
codominance
both traits are expressed together (ex: red + white make a red and white)
_________ is the effect of a gene mutation is dependent on the presence or absence of mutations in on or more other genes
epistasis
one gene masks or modifies the expression of another, EXAMPLE: albinism, where a mutation in the TYR gene (which codes for tyrosinase, essential for melanin production) prevents pigment production, resulting in pale skin and hair, regardless of other skin color genes.
meiosis
a cell division of germ cells in sexually-reproducing organisms that produces gametes
what results in the genomic variation in offsprings?
gene crossover
the greater the distance between two genes the higher the chance of _______________
recombination
_______ _________ is the difference in DNA among individuals or the differences between populations among the same species
genetic variation
what causes genetic variation?
mutation and genetic recombination
chromosomes that contain genes that determine the sex of an individual
sex chromosomes
chromosomes that do not contain genes that determines the sex of an individual
autosomes
chickens have ___ pairs of autosomes and ____ pair of sex chromosomes = ___ chromosomes
- 38 pairs of autosomes
- 1 pair of sex chromosomes
- 39 pairs (78) chromosomes
chickens have ____ billion base pairs (haploid)
1.2 billion
what was the first chicken genome reported in 2004?
red jungle fowl (an ancient chicken breed)
why is genetics important for poultry production? (industry reasons and specific bird effects)
- growth, meat yield, feed efficiency
- egg quality, egg laying rate
- health and welfare
- economic impact
why is genetics important for poultry production?
understanding poultry phenotype via genetic analysis
what are some example of poultry genetics?
- duplex comb (D)
- No tail
- Crest (Cr)
- Creeper (Cr)
what is the duplex comb poultry genetics?
- makes different comb shapes
- autosomal incomplete dominance
what is the no tail in poultry genetics?
if a deletion occurs the chicken will have no tail
what is the crest gene in poultry genetics?
determines the feathers on the top of the head including Houdan and Silkie
what is the creeper gene in poultry genetics?
determines leg length of the bird. heterozygous Cp shows the creeper trait while homozygous Cp is normal.
what are the different comb phenotypes in poultry?
- single-combed wild type
- pea-combed
- rose combed
- walnut-combed
what is the barring gene in poultry genetics?
- sex-linked barring
- the feather barring pattern in birds
what is the feathering gene in poultry genetics?
- sex-linked barring delayed feathing
- the reason you can sex chicks because female chicks have a slightly faster feathering than males
what is dwarfism in poultry genetics?
- one sex-linked recessive gene
- reduces body weight of the makes and females
- caused mutations in the growth hormone receptor gene on the Z chromosome
GWAS
genome wide association study
what are traits that are used to help with the future of genetics in poultry production?
- egg production and quality of layers
- growth traits in broilers
pangenome
a collection of the common and unique genomes that are present in a given species, captures the known variants and haplotypes and reveals new alleles at structurally complex loci
the pangenome captures ________ present among modern poultry breeds
diversity
the pangenome shows the ______ and _______ of the domestic chickens
origin and diversity
what is the purpose of genome editing?
modifying the genetics of the bird to improve production
substitutions, insertion, deletions, amplifications, chromosomal translocation, inversion…. are examples of genome ______________
modification
transgenesis
exhibiting a new property
genome editing and gene targeting
artificial genome editing, targeted gene modification
homologous recombination is __________ gene editing
precise
why are we doing genetic engineering?
to identify gene functions. understanding which region of DNA is responsible for phenotypes.
forward genetics
having a know phenotype and then using DNA sequencing to discover the genotype
reverse genetics
having a known genotype and then using genome editing to discover the phenotype
what type of genetic tool is used in forward genetics to discover genotype?
DNA sequencing
what type of genetic tool is used in reverse genetics to discover phenotype?
genome editing
example of forward genetics in poultry
crest phenotype
example of reverse genetics in poultry
MLPH
what are specific reasons why we are doing genetic engineering?
- growing population and limited resources
- animal/zoonotic diseases
- climate change
- animal welfare
- nutritional values
why are we doing genetic engineering?
can help humans (consumers and producers), animals and the earth
why does it make genetically modifying birds more difficult?
poultry make it more difficult because they create and egg shell around the yolk making it more difficult to target specific cell types
less than ____% of the cells in the egg are germ cells
10%
when genetically modifying poultry, we target the blastoderm injecting them with a ______ ______
viral vector
how do the germ cells migrate in the bird during develop so it can be collected?
through the blood
issues on genome-edited animals
- safety
- diversity and sustainability
what safety issues can there be with on genome-edited animals
off-target effects (things that changed that you did not want to change)
what genome edit in chickens is FDA approved
kanuma
what is the kanuma gene edit?
- mass production of recombinant protein
- is used to treat people with a diagnosis of lysosomal acid lipase (LAL) disease
what is collected and used to genetically modify birds?
primordial germ cells (PGC)
how are primordial germ cells collected?
- from the embryos blood
- from the gonads
what are the three common tools used for genetic engineering?
- Cre/loxP (recombination)
- piggyBac transposon
- CRISPR CAS9
what is homologous recombination?
a type of genetic recombination in which nucleotide sequences are exchanged between two similar or identical molecules of DNA
_________ ___________ is a type of genetic recombination in which nucleotide sequences are exchanged between two similar or identical molecules of DNA
homologous recombination
homologous recombination repairs DNA before the cell enters _________ or __________
mitosis or meiosis
homologous recombination has extremely ____(low/high) editing efficiency
low
site specific recombinases
enzymes that catalyze DNA strand exchange at specific DNA sequences, enabling precise gene editing for insertions, deletions, inversions, or translocations
T or F: site specific recombinases are reversible when applied to gateway cloning
FALSE; they are irreversible
what is a viral vector system in gene editing?
ability to enter a cell and hijak its machinery to produce viral proteins
viral vector system can modify viral genome to deliver ___/___
DNA/RNA
the viral vector system has _________ integration
random
what is a transposon?
a mobile DNA sequence that can move from one location to another within a genome, potentially causing mutations or altering gene expression
the P element encodes a __________ enzyme, which recognizes terminal inverted repeats of the P element and catalyzes excision and reinsertion
transposase
the gene editing tool piggyBAC is the most common __________ system used
transposase
what is an example of a programmable genome editing tool commonly used to edit the chicken genome?
CRISPR/Cas9
Cas9 + gRNA =________ _____ ________
targeted gene modification
CAS9 can have many different effects on the genome by binding with many different _________, this includes cut DNA to generate knockouts, histone modification, DNA base editing, and more
effectors
why are we doing genetic engineering? (4 reasons)
- to improve economic traits
- to acquire disease resistance
- to assist reproduction
- to study specific gene functions
what are some examples of genetic engineering done in poultry?
- allergen free eggs
- modify chicken egg proteins
- mass production of recombinant protein (kanuma)
kanuma from transgenic chicken eggs is used to treat people with a diagnosis of ___________ deficiency
lysosomal acid lipase (LAL)
how is genetic engineering assisting reproduction in poultry?
to collect primordial germ cells from other birds and then test cross them with a different species
________ ____ ______ mediated germline transmission in chickens
primordial germ cells
what is the Cre/loxP system?
a site-specific recombination technique that allows researchers to alter DNA in specific ways
CRISPR
clustered regularly interspaced short palindromic repeats
