Module 1- overview of animal nutrition Flashcards
(144 cards)
1
Q
what are the 2 broad categories of animal nutrition?
A
1) maintenance functions- nutrients to keep animal alive
2) productive functions
- production of food for human consumption
2
Q
6 major reasons why animal nutrition is important
A
1) efficiency
2) disease susceptibility & recovery
3) quality of product
4) reproductive success
5) economics -> feed efficiency
6) environment - GHG emissions, N/P excretion
3
Q
what is a nutrient
A
chemical element or compound that is required for normal body functions
4
Q
6 major classes of nutrients
A
1) carbs
2) lipids
3) protein
4) minerals
5) water
6) vitamins
5
Q
most important nutrient
A
water
6
Q
essential vs non-essential nutrients
A
essential: must be provided in the diet bc the body cannot make sufficient quantities
non-essential: body can make in sufficient quantities
- building blocks must be available though
7
Q
ration definition
A
specific daily allocation that an animal needs to eat
8
Q
diet definition
A
mixture of foodstuff or feedstuff that is going to provide required nutrients
9
Q
how do plants synthesize proteins?
A
use nitrogen to make AA
10
Q
what does the metabolism of carbs & fat provide to the animal
A
energy
11
Q
what type of feeds contain high protein? why?
A
- animal based feeds & plant by-products
- when oil is removed=protein becomes concentrated
12
Q
composition of the animal body (water, protein, fat, minerals, carbs %)
A
60% water
16% protein
20% fat
4% minerals
<1% carbs
13
Q
protein : fat ratio will ( ) as animals get older
A
decrease
14
Q
what increases with age?
A
fat
15
Q
digestion
A
break down feed into smaller molecules for absorption
16
Q
when does digestion, absorption & metabolism occur?
A
digestive tract- digestion & absorption
post-absorptive- metabolism
17
Q
chemical breakdown of feed
A
HCI & gastric secretions
18
Q
digestion is composed of what 2 types of feed breakdown
A
physical & chemical
19
Q
gastric digestion
A
facilitated by enzymes secreted by the animal
20
Q
primary form of digestion for monogastrics
A
gastric digestion
21
Q
fermentative digestion
A
digestion that takes place in specialized compartments that are located before the stomach & small intestine, or after the small intestine
22
Q
animals who digest before stomach & small intestine vs after
A
before- ruminants
after- horses
23
Q
T or F: pigs primarily use gastric digestion, but still have hund gut fermentation
A
T
24
Q
flow of monogastric digestion
A
1) mouth
2) esophagus
3) stomach
4) small intestine
5) cecum + colon (large intestine)
25
salivary amylase function
digest starches in mouth
26
3 accessory digestive organs of monogastric
1) teeth
2) salivary glands
3) liver
27
stomach functions (4)
1) muscular contractions
2) HCI secretion
3) pepsinogen secretion
4) chyme formation
28
chyme
partially digested feed + water + HCI + enzymes
29
pH of chyme
2-3
30
where does most of the absorption take place in monogastrics?
1st 2 compartments -> duodenum + jejunum
31
duodenum function
secretion of pancreatic juices that contain bicarb will buffer chyme so enzymes can function
32
liver function (2)
1) produce bile
2) lipid digestion with bile salts
33
gallbladder function
stores bile
34
what are brush border enzymes produced by
villi & microvilli
35
list 4 differences between chicken and pig digestion?
1) no teeth -> use beak
2) crop-> feed storage
3) proventriculus-> secrete HCI & enzymes
4) gizzard- mechanical digestion of feed
36
how does mastication help digestion
smaller particles increase surface area for enzymes to act on
37
reticulum vs omasum structure
reticulum- honeycomb
omasum- leaves of tissue that squeeze water out of feed
38
where is gastric digestion initiated in ruminants
abomasum
39
T or F: small intestine secretions in ruminants are very similar to pigs
T
40
the rumen is an ( ) environment. why?
anaerobic
- supports growth of microorganisms
41
what are the 2 most important microorganism groups in the rumen
bacteria & protozoa
42
what GHG do archaea produce
methane
43
why is it necessary bacteria in the rumen are attached to feed particles?
enzymes are on outside wall of microorganism so they must come into contact with feed in order for fermentative digestion to take place
44
what does microbial fermentation of starch, cellulose & hemicellulose produce?
VFAs
45
where are VFAs primarily produced & absorbed
rumen
46
what are the 3 VFAs
1) acetate
2) propionate
3) butyrate
47
what is the major source of energy for ruminants?
VFAs, then microbial protein
48
microbial protein
major source of protein formed by amino acids for the animal
49
major site of absorption for monogastrics
small intestine
50
end product of protein digestion
amino acids
51
end product of starch digestion
glucose
52
end product of lipid digestion
fatty acids -> go to lymphatic system
53
what facilitates absorption
villi
54
villi
tiny projections into the lumen of the small intestine
55
microvilli
tiny hair-like projections that line the villi
56
how os O2 supplied to small intestine?
there is a rich blood supply to villi & microvilli
57
venous drainage
takes away nutrients that have been absorbed
58
lacteal function
takes away end products of lipids by absorbing & draining into lymphatic system
59
major functions of microvilli (2)
1) increase surface area for absorption
2) produce brush border enzymes
60
brush border enzymes are important for what digestion of what 2 nutrients?
carb & protein
61
density of papillae in the rumen depends on what?
type of diet
62
what type of diet produces lots of VFAs?
high grain
63
T or F: rumen papillae do not secrete enzymes
T
64
rumen papillae function
increase surface area
65
major site of absorption in ruminants
rumen & small intestine
66
major site of absorption in monogastrics
small intestine
67
3 mechanisms of absorption
1) diffusion
2) facilitated diffusion
3) active transport
68
diffusion & example
moving down from high to low concentration
- glucose in lumen -> bloodstream
69
facilitated diffusion
uses transporter to facilitate movement of substrates from high to low concentration
70
active transport
requires ATP, goes against concentration gradient (low to high concentration)
71
retention time
amount of time the feed spends in the GI tract
72
retention time is longer in what kind of animals
large animals that depend on fermentative digestion
73
what does retention time depend on?
body size
74
animals who use fermentative digestion are more dependant on a higher contribution of energy from?
VFA
75
anabolism
building of complex compounds from small molecules
- uses energy
76
catabolism
breakdown of molecules into smaller energy
- releases energy
77
example of catabolism
generation of ATP
- glucose oxidation to produce ATP
78
3 factors that may change optimal range of nutrients
1) type of animal
2) physiological state
3) environmental conditions
79
what type of defect is when we see a decrease in production
functional defect
80
5 characteristics that make a good diet
1) contain essential nutrients in correct amounts
2) palatable
3) digestible
4) economical
4) non-toxic
81
feed costs account for ()% of production costs
50
82
example of nutrient inhibitor
trypsin in soybean
83
what is the central metabolic junction
glucose
84
T or F: energy is a nutrient
F
85
2 major energy substrates
carbs & fats
86
when would proteins be used for energy?
if diet is deficient in carbs/fats
87
what is the primary form of nitrogen secretion
urea
88
T or F: vitamins & energy supply energy
F
89
2 examples of feeds put into a diet to provide energy?
1) cereal grains - barley, wheat, corn, oats
2) lipids: canola seed, flax, soybean
90
T or F: canola meal is a sufficient source of energy in the diet
F -> only contains 2% fat
91
what is the fuel of metabolism
energy
92
energy =
the potential to do work
93
bomb calorimetry
measures the gross energy of feed
94
gross energy
heat released when feed is completely oxidized to CO2 & H2O
95
heat of combustion of feed =
gross energy of feed
96
what will be produced feed is when oxidized in a cell, not bomb calorimeter
energy in form of ATP
97
what does the water in bomb calorimetry represent
amount of heat produced
- can measure this by measuring temp of water before & after
98
how much O2 is added to bomb calorimetry
25-30 atmospheres
99
energy equivalent of bomb calorimerty
correction factor to account for heat capacity of calorimeter & environment
100
what is often used as an energy equivalent
benzoic acid
101
hydrothermal equivalent (HE)=
weight of sample x gross energy / temp 2 - temp 1
102
GE=
HE x diff in temp / sample weight
103
kcal vs mcal
kcal- 1000 calories
mcal- 1000 kcal
104
why are fats more energy dense?
contain more carbon & hydrogens compared to proteins & carbs
105
lipids has ( )x more energy than carbs & protein
2.25
106
limitation of gross energy
does not tell how much of that energy is available to the animal
107
T or F: GE is not 100% available to the animal
T
108
why is GE not 100% available to the animal
does not account for energy losses due to digestion & metabolism of the feed
109
what is the single largest loss of energy that is consumed by the animal
fecal energy
110
T or F: feed is 100% digestible
F
111
why is it apparent digestible energy?
bc of sloughed off epithelial cells, microorganisms & enzymes
112
what happens if you do not account for sloughed off epithelial cells in the feces
overestimate how much energy is lost in the feces
113
what factor affects gross energy value of the feed
chemical composition
114
is DE higher in monogastrics or ruminants? why?
monogastrics
- pigs have more digestible feed
115
metabolizable energy (ME) =
DE - (UE-GEL-GILL)
116
how is energy content of urine determined
bomb calorimetry
117
major energy loss in urine in monogastrics vs avian species
monogastrics- urea
avian- uric acic
118
T or F: fermentative digestion of feed is inefficient
T
119
UE loss is higher in which animals
ruminants
120
higher ( ) diets produce more methane
forage
121
what is used to measure gaseous losses in cattle
uses SF6
122
net energy
accounts for energy lost as heat during digestion & metabolsim
123
NE=
ME - heat increment
124
why would feed intake decrease during summer?
animal is trying to regulate body temp bc heat production increases after a meal
125
do ruminants or monogastrics have a higher heat increment?
ruminants
126
increase in diet digestibility = ( ) in heat increment
decrease
127
do forages or grain digestion produce more heat
forages
128
animals in a catabolic state have a ( ) heat increment than anabolic state animals
higher
129
amino acid imbalance causes a ( ) heat increment
higher
130
more frequent feeding has ( ) heat increment than less frequent feeding
smaller
131
why does feeding smaller, more frequent meals produce a smaller heat increment compared to feeding larger, less frequent meals?
work of digestion for smaller meals is smaller = less heat produced
132
direct vs indirect calorimetry examples
direct: heat production
indirect: O2 consumption, carbon & nitrogen balance
133
direct vs indirect calorimetry
direct: heat production measured directly
indirect: gaseous exchange to estimate heat loss
134
closed circuit calorimetry
totally enclosed, no air is leaving
- can measure how much CO2 is absorbed
135
open circuit calorimetry
atmospheric O2 is entering, measure how much CO2 is produced
136
2 advantages & disadvantages of net energy
advantage:
- accounts for metabolic cost of nutrient metabolim
- can predict performance of animal
disadvantage:
- expensive
- time consuming
137
what energy is used to formulate pig diets
NE
138
what energy is used to formulate poultry diets
ME
139
what energy is used to formulate ruminant diets? why?
NE
- heat increment & gaseous energy losses are large so need to account for these
140
TDN
total digestible nutrients
- used to express energy content of feed before bomb calorimetry
141
TDN uses values from
proximate analysis
142
proximate analysis system
used to measure composition of the feed
143
T or F: TDN looks at digestible nutrients that are contained in the feedstuffs
F
144
DE for pigs, ruminants fed concentrate & ruminants fed roughages
pigs: 80%
concentrate: 70%
roughages: 50-60%
