Protein in Ruminants Flashcards
what are the major roles of rumen microorganisms
- fermentation of diatary carbohydrates (yeilds atp for bacterial growth, VFAs as a waste product)
- breakdown of dietary nitrogenous compounds
where do nitrogenous compounds come from in feeds and what type of feeds
- true proteins - EAA, NEAA linked by peptide bonds
- canola meal, soybean meal and fish meal
what kind of nitrogenous compounds are in feeds
- NPN
- Urea
- Ammonia
- free amino acids, small pepetides, nucleic acid
what is NPN
- non protein nitrogen
- or protein not associated with protein
what is Urea
- the most common form of NPN
- up to 2% in beef cattle rations
where does ammonia, free AA small peptides and nucleic acids
- fermented forages
what utilizes ammonia
- bacteria can used ammonia as a protein source for protein synthesis
- protozoa dont have enzymes to use ammonia for protein synthesis (they engulf bacteria themselves)
what determines the perfeered N source
depends on bacterial species
- fiber digestors = fibrolytic and cellulolytic prefer an ammonia N source
- starch digesters = amylolytic prefer AA and peptides as preferred nitrogen source
how does ATP influence N
- coupled fermentation or nutrient synchronization
- nitrogenous compounds available at the same time as energy needed to drive protein synthesis
why maximize ruminal MP production
- microbial protein is the most important source of AA in ruminants
- most of the AA is absorbed in the small intestine
- MP is a high quality, cheap protein for ruminant, high in lysine and methionine
what factors can effect rumen MP production
- available energy ( Fro, ATP and fermentable carbs)
- rumen ammonia levels
- synchronization of fermentation (coupled fermentation)
- preformed amino acids and peptides
- other nutrients (sulfure and phosphorus)
- rumen environment
what are the major factors of rumen ammonia concentration
- time post-feeding (once fed fermentation occurs, ammonia goes up, reaches peak and then goes down till next meal)
- frequency of feeding (the more fed, the more stable the rumen ammonia concentration
- protein/ ammonia source ( fish meal - slowly degraded conola meal - quickly degraded) fermented forages - high ammonia conce rises rapidly
- energy availability
what is rumen dilution rate
proportion of total volume leaving the rumen
- fluid, particular passage 2-20% per hour - liquid phase flows out much faster
- rumen microbes leave with both the solid and fluid phases - when they leave faster, more microbes reach the small intestine
the faster dilution rate, the greater the rate of outflow of microbial protein. What is the reason for this?
- if bacteria flow out faster, the protozoa cant consume then less
- less bacteria are used to sustain them as nutrients
- faster dilation rate is more is a more efficient way of achieving microbial protein
what is the role of protozoa in overall rumen balance
- dont need them, protein metabolism would be more effective without them
- 20-70% of rumen microbial biomass
- 10-40% of total tumen nitrogen
- only 20-40% washout to lower gut - only minor contribution to metabolizable protein