Term
| What are the major sources of GI endogenous nutrients? |
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Definition
digestive enzymes, mucosal cells, gastrointestinal bacteria/microflora
salivary juice
biliary juice
Any gastrointestinal secretion |
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Term
| Why don't the corrections for GI endogenous nutrient losses not make significant difference in digestibility values (apparent vs true) for some nutrients? |
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Definition
-need to correct for GI endogenous losses when calculating digestibility of CP, AA and minerals otherwise will significantly underestimate
-less effects on DM, lipids & sugars digestibility as there is not much endogenous secretion of these
True nutrient digestibility corrects for GI endogenous metabolic losses due to texture of feed ingredients |
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Term
| Why do the corrections for GI endogenous nutrient losses not make significant difference in digestibility values (apparent vs true) for some nutrients? |
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Definition
Microbial fermentation & biosynthesis, protein losses, digestive tract secretions etc. can all skew the apparent results for digestibility of proteins, amino acids, minerals and vitamins
-significant endogenous loss of minerals & vitamins, can skew the measured digestibility values greatly if not accounted for |
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Term
| Discuss if one can effectively use the slope-ratio assay for studying mineral bioavailability in feed ingredients for mature animals such as dogs, cats, boars, sows, laying hens or lactation cows? |
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Definition
-estimates digestion and utilization of minerals, especially calcium and phosphorous
-effective in animals with fast growth rates to determine mineral bioavailability
-not a good choice to test on mature animals because of slower growth, and increased costs & labour, and are less sensitive to mineral needs so won't give a clear linear response |
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Term
| Discuss which endpoint or level of feed energy value evaluation systems (DE, ME or NE) is very challenging and is specific to and is affected by extreme environmental temperature factors |
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Definition
Net energy is sensitive and easily affected by extreme environmental temperature factors
NE = ME + HP
Where HP = metabolic energy for maintenance + Heat increment of feeding |
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Term
| How does mechanical processing improve feed DE values? |
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Definition
NDF and ADF and insoluble, limit DE for monogastrics
Lignin limits DE for all herbivores
-grinding, rolling, cracking, open up plant cell wall, dehulling to destroy the semi-crystalline structure of starch
-add exogenous enzymes to facilitate digestion
-crushing etc increases surface area for enzyme action |
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Term
| Why do feed intake levels affect DE in ruminants? |
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Definition
-feed intake levels affect feed retention time in rumen, thus affecting how well microbes can ferment the feeds in ruminants
-DE values determined to guide ration formulations are essentially measured ad lib feed intake (voluntary feed intake level) in ruminants
-needs to be careful not using the DE values measured for the animals with restricted feed intake levels |
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Term
| Why will the NE feed energy values from the NRC lose their guiding values if certain species are housed under temperatures outside of their 'thermoneutral zone' |
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Definition
NE is ME further corrected for heat increment. If the animal is housed outside the thermal neutral zone, it will need to either increase metabolism (increase heat increment) or decrease metabolism (decrease heat increment) depending if it is above or below the zone. This means the NE will not be accurate and it will lose its guiding value.
Dairy cattle, swine and beef cattle esp. |
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Term
| What will happen to the utilization of feed energy if animals are fed a significant amount of raw beans or raw bean materials? |
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Definition
Raw beans contain lectin and trypsin/chymotrypsin inhibitors. These affect protein digestion and damage the mucosa of the GI tract resulting in diarrhea. Therefore, the energy in raw beans and the diets they're incorporated into isn't as useable by the animal. This can be overcome by cooking the beans as heat denatures the lectins and inhibitors.
(temp over 135 will denature proteins too much!) |
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Term
| How can you help curb GHG methane emission from ruminants through feeding? How has Canadian canola research made contributions to the global animal feed industry? |
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Definition
CH4 emissions due to active fermentation in the rumen
-feeding plant oils & monensin, which increase feed conversion efficiency and lowers methane production
-development of Canola, a variety of rapeseed which is low in erucic acid and glucosonates (anti-nutritive factors) to optimize productivity |
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Term
| Discuss bioavilable feed energy value evaluation systems which are used for poultry and the rationale behind it |
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Definition
Total metabolizable energy (TME) ...ME system
on as-fed or air-dry basis
because feces & urine are excreted via the cloaca together, can't measure individual losses
Using NE would be ideal but this is very expensive and not much research is available |
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Term
| Discuss bioavilable feed energy value evaluation systems which are used for beef cattle and the rationale behind it |
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Definition
Total Digestible Nutrients (TDN) ...NE system
NE system has lots of data available & government support, however using NE information from warm areas may be misleading for Western cattle industry as NE is sensitive to temperature extremes |
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Term
| Discuss bioavilable feed energy value evaluation systems which are used for dairy cows and the rationale behind it |
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Definition
Energy values expressed as TDN...use NE system
-major net energy output is lactation, lots of research & funding from the government |
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Term
| Discuss bioavilable feed energy value evaluation systems which are used for small ruminants and the rationale behind it |
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Definition
Energy values expressed as TDN, use TDN & ME system
-reported data and funding is readily available. Significant urinary loss in these animals |
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Term
| Discuss bioavilable feed energy value evaluation systems which are used for horses and the rationale behind it |
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Definition
Expressed as DE...use DE system
-limited data & funding available to measure ME and NE values in feeds & energy requirements
-housing environment varies greatly for sport vs pleasure, NE system would not be practical |
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Term
| Discuss bioavilable feed energy value evaluation systems which are used for swine and the rationale behind it |
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Definition
DE, ME and NE systems
-lots of data & government support available, and varying housing conditions which may require use of DE, ME or NE |
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Term
| Discuss bioavilable feed energy value evaluation systems which are used for dogs & cats and the rationale behind it |
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Definition
Use ME system
Variable housing for dogs and cats would make NE impractical
Limited support for data research to be able to use NE
High protein diet = high urinary loss which needs to be accounted for |
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Term
| Discuss bioavilable feed energy value evaluation systems which are used for fish & shrimp and the rationale behind it |
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Definition
Use DE system
NE not practical due to varying water temperatures
Very little renal loss from fish & shrimp so don't need to account for that |
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Term
| How does mechanical processing improve CP and AA digestibility from plant sources in animals? |
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Definition
-grinding/rolling/cracking to de-hull
-protein isolation
-remove antigenic protein in soybean meal
-supplement exogenous enzymes such as phytase, cellulase, hemi-cellulases, proteases
Helps to overcome the insoluble properties of NDF & ADF and remove antigenic components which limit ileal CP & AA digestibility by increasing surface area and supplying enzymes to help in breaking down the insoluble fibers |
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Term
| How do phytases/cellulases/hemicellulases improve CP digestibility in animals? |
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Definition
| Phytase cleaves phytate which releases phytin to help digest insoluble fibers. Phytate is a compound found in plants that binds to certain nutrients making them unavailable for animals to digest. Cellulases and hemicellulases (including beta-glucanase) have a viscous impact and aid in the degradation of polymer fibres. Cellulases and Hemicellulases degrade the polymer fibers - they do not directly breakdown the cell wall. |
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Term
| Why is odor associated with dietary proteins, and the nitrification/denitrification used in converting farm animal manure N compounds into greenhouse gases? |
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Definition
Anaerobic bacteria in the intestine converts L-tryptophan to 3-methyl indole (skatole). Skatole can also be produced from other sulfur containing amino acids such as other indoles, sulfides and phenols.
Farm animal manure N compounds are converted into greenhouse gases via nitrification first, microbes convert NH4+ to nitrate. Denitrification sees the conversion of nitrate to N2O during its storage in lagoon (manure slurry) and in soil, causing greenhouse gas effects |
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Term
| How would ammonia emission from livestock production contribute to the effect of nitrate pollution in underground drinking water resources? |
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Definition
Nitrate penetrates the soil and leaches into drinking water
Nitrogen in ammonia emission → ammonia in rain → nitrate in soil → nitrate leaches into drinking water (pollution) Nitrification is the conversion of ammonia to nitrite and then nitrite to nitrate |
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Term
| Why can raw bean or raw bean meal severely affect the protein digestion & biological functions of animals? What are the effects of the maillard reaction? |
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Definition
These feeds contain trypsin and chymotrypsin inhibitors which prevent protein cleavage by trypsin and chymotrypsin. These inhibitors negatively affect digestion and normal gut microflora of both monogastrics and ruminants. Through heat processing, these effects can be eliminated.
Maillard reaction is the chemical reaction between amino acids and reducing sugars that gives browned food a desired flavor. AA participate with reactions with the OH groups of sugars and crosslinking occurs. The effects are that it is damaging to essential amino acids which cannot be properly absorbed/digested and are lost through urine. Less biologically valuable. |
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Term
| What CP & AA nutritive value evaluation systems are used for poultry and what is the rationale? |
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Definition
True Crude Protein & Standardize Ileal AA Digestibility
-little microbial fermentation or digestion in large intestine
-little endogenous losses to account for
Availability of essential AA
-good for chicks
-measures one feed at a time, costly and not practical |
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Term
| What CP & AA nutritive value evaluation systems are used for beef cattle and what is the rationale? |
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Definition
Metabolizable Crude Protein
-Feed protein degradation in the ruminant animals
-Corrects for ruminal degradable CP, ruminal degradable (microbial degradable) CP and endogenous losses
-Reflects the metabolized protein |
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Term
| What CP & AA nutritive value evaluation systems are used for dairy cattle and what is the rationale? |
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Definition
Metabolizable Crude Protein
-Feed protein degradation in the ruminant animals
-Corrects for ruminal degradable CP, ruminal degradable (microbial degradable) CP and endogenous losses
-Reflects the metabolized protein |
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Term
| What CP & AA nutritive value evaluation systems are used for small ruminants and what is the rationale? |
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Definition
Metabolizable Crude Protein
-Feed protein degradation in the ruminant animals
-Corrects for ruminal degradable CP, ruminal degradable (microbial degradable) CP and endogenous losses
-Reflects the metabolized protein |
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Term
| What CP & AA nutritive value evaluation systems are used for horses and what is the rationale? |
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Definition
Total CP & Total Lys
-useful to ensure enough Lys & CP is present
-true pre-cecal CP and AA digestibility would be useful but not practical given the wide range of feed ingredients used in horses
-know LYS requirements and total CP but not other specific essential AA |
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Term
| What CP & AA nutritive value evaluation systems are used for swine and what is the rationale? |
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Definition
CP, Total AA, Apparent & True Ileal Digestible AA
-minimal microbial fermentation and digestion in the LI
-little endogenous losses here of CP and AA
-lots of info available on CP, total essential & semi-essential AA requirments with corrections for some AA endogenous contributions |
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Term
| What CP & AA nutritive value evaluation systems are used for dogs & cats and what is the rationale? |
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Definition
CP, Total Chemical Contents of Essential AA, plus Taurine (for cats)
-diets are high in animal proteins, very digestible
-lots of information on total CP & essential/semiessential AA requirements for dogs & cats |
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Term
| What CP & AA nutritive value evaluation systems are used for fish & shrimp and what is the rationale? |
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Definition
CP & total essential/semi essential AA contents
-CP & AA requirements measured with easily digestible diets or simply pure nutrients
-protein feed sources are very digestible |
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Term
| Why are viscous soluble fibre components such as beta glucan and pectin not significant concern in ruminant nutrition? |
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Definition
Pectin and beta glucans limit the digestion of dietary starch and proteins in monogastrics. However, these viscous soluble fibre components are highly degradable in rumen with little concerns.
Ruminants can degrade pectins and beta-glucans into heat and VFA’s with their rumen microbes. |
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Term
| Discuss what is starch gelatinization and its impact on grain starch utilization in weanling pigs. |
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Definition
| Starch gelatinization is the process of solubilizing (extrusion/steaming/microionization) the starch granules made of semi-crystalline structure of starch. Weanling pigs have low gastric acid secretion and not sufficiently low gastric pH, so gelatinization allows for better utilization of grain starch. If starch gelatinization is not done the weanling pigs will get diarrhea. |
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Term
| Why is liquid swine manure from intensive swine production considered a major source of methane in GHG emissions? |
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Definition
uring prolonged storage of undigested carbohydrates (i.e. starch and fibre), there is anaerobic microbial fermentation which produces CH4.
Pigs have incomplete digestion of fibre and during manure storage in lagoons there is anaerobic microbial fermentation. More fermentation = more greenhouse gas. We can improve this by utilizing crude fibre.
We can improve fibre utilization by adding enzymes to help digest fibre (HCulases, cellulases) |
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Term
| What is surface water eutrophication and what are the associated potential negative effects of intensive livestock production? |
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Definition
| Inefficient utilization of P leads to excessive manure Phosphorus and P run-off after manure application to surface soil. Soil can only take so much P then run off will occur. P goes into water, creates algal booms and depletes oxygen in the water. This causes fish and marine life death. |
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Term
| What are the major environmental concerns facing excessive Cu and Zn in manure? |
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Definition
| can contribute to Cu and Zn- specific antimicrobial resistance and disturbs soil microflora that are essential to the nitrification-denitrification cycle |
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Term
| Alkaline pH causes deprotonation of ammonium. leading to NH3 emission. What causes alkaline pH in livestock manure? |
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Definition
Inefficient utilization of macronutrients (ions/electrolytes) : Na, Cl, K, S and Mg
This leads to secretion in manure __ produces alkaline feces by macro-mineral ions which inhibits NH3 → NH4 conversion |
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Term
| Why is there very little research done on the true bioavailability of trace minerals & vitamins in feeds? What technique would you choose to estimate true bioavailbility of trace minerals & vitamins? |
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Definition
-It is not very expensive to supplement animals with minerals and vitamins
-It is difficult to set up a slope- ratio assay.
-contents of trace minerals in feed is very low
-no concerns with their effects on the environment
Should do digestibility using true fecal/total tract digestibility analysis but would have to correct for endogenous losses |
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