RUDP and RDP.pptx digestion and utilization

Digestion and utilization of RDP and RUP and NPN substances in rumminants

1. Digestion & Utilization of RDP,RUP and NPN substances in ruminants Submitted by: Sarmad Jamshaid Reg.# F23BNUTR3M01002 M.Phil. Animal Nutrition 2 nd semester Course: RUM NUTR 32204 Submitted to: Prof. Dr. Nasir Ali Tauqeer

2. Introduction Protein is important for ruminants. Growth and development Reproduction Milk production Rumen microbial health Enzyme functions Ruminant protein digestion differs from mono-gastric animals, with the rumen being a specialized foregut where microbial fermentation is pivotal for protein breakdown and utilization.

3. Digestion of protein

4. Fractions of dietary protein Rumen degradable Protein (RDP) Rumen undegradable protein (UDN) Rumen Degradable Protein (RDP) is the fraction of Crude Protein ( CP) consumed which is broken down by rumen microbes. And remaining protein which reaches the small intestine without degradation called as Rumen undegradable protein (UDN).

5. Digestion of Rumen degradable Protein (RDP) Rumen degradable Protein (RDP) hydrolysed to peptides and amino acids by rumen microorganisms, B ut some amino acids are degraded further, to organic acids, ammonia and carbon dioxide. The main proteolytic organisms are Prevotella ruminicola , Peptostreptococci species and the protozoa. Two major steps are involves in protein degradation in the rumen: 1- Hydrolysis of peptide bonds to produce peptides and amino acids . 2- Deamination and degradation of amino acids .

6. The ammonia produced due those processes , together with some small peptides and free amino acids, is utilised by the rumen organisms to synthesise microbial proteins. Some of the microbial protein is broken down in the rumen and its nitrogen is recycled (i.e. taken up by microorganisms). The new NRC (2001 ) suggests that maximum milk and milk protein yields occur when RDP is 12.2% of diet dry matter.

7. An important feature of the formation of microbial protein is that bacteria are capable of synthesising indispensable as well as dispensable amino acids . The ammonia in rumen liquor is the key intermediate in microbial degradation and synthesis of protein. Estimates of the optimum concentration of ammonia in rumen liquor vary widely, from 85 mg/ L to over 300 mg/ L ( Gumilar et al. 2018)

8. If the food is poorly supplied with protein and the concentration of ammonia in rumen liquor is low . T he quantity of nitrogen returned to the rumen as urea from the blood may exceed that absorbed from the rumen as ammonia. This net gain in ‘recycled’ nitrogen is converted to microbial protein, which means that the quantity of protein reaching the intestine may be greater than that in the food. With most feeds each kilogram of organic matter digested in the rumen yields approximately 200 g of microbial protein.

9. Limitations of RDP Ammonia : Excessive intake of RDP can lead to ammonia toxicity and nitrogen loss through urinary excretion. Supplementation frequency : According to Bohnert et al. (2002) DM digestibility decrease with increase in RDP from daily to every 6 days. Crude Fiber: T here is negative correlation between CF and RDP. High CF content in diet will decrease RDP and increase RUP.

10. Factors Affecting Ruminal Protein Degradation Chemical Nature of the proteins Solubility – More soluble proteins degraded faster some soluble proteins not extensively degraded Egg ovalbumin, serum proteins 3-dimensional structure – Affects solubility & availability Chemical bonding Disulfide bonds – Reduces degradation

11. Physical barriers Cell walls of plants Cross linking of peptide chains – Reduces degradation E.g. Aldehydes, Tannins Feed intake Rate of passage – Time proteins remain in the rumen Feed processing Rate of passage Heat damage – Complexes with carbohydrates

12. Rumen undegradable protein ( RUP ) digestion Rumen undegradable protein (UDN) is also called bypass protein or escaped protein or rumen undegradable protein (RUP) . It is the portion of intake protein that escapes rumen degradation and is digested directly in the small intestine. About 80 to 85 % of the microbial bacterial protein or true protein that flows out of the rumen is digested in the small intestine and it is expressed as a percentage of crude protein (CP).

13. Protein digestion in the small intestine The nitrogen entering the duodenum is a combination of microbial protein, undegraded protein and endogenous protein. Nitrogen entering the small intestine from the stomach can range from 30 - 100% microbial protein and - 70 % undegraded protein. Digestion of protein in the abomasum and the small intestine in ruminants is similar to that in monogastric animals. The digestion of protein in the abomasum is carried out mainly by pepsin in a very acidic environment (pH 2).

14. Absorption of amino acids and peptides The most active site of amino acid and peptide absorption is the mid to lower ileum. There is a preferential absorption of essential over non - essential amino acids from digesta flowing through the small intestine. For example, absorption of lysine and histidine is higher than the absorption of glutamine and glycine .

15. Sources of Bypass Protein Naturally Protected Proteins Heat Treatment ( Maillard reactions ) Chemical Treatment ( Formaldehyde , lignosulfate ) Esophageal Groove (For young one, liquid protein) Post Rumen Infusion (Fistula) Encapsulation of Proteins Amino Acids Analogs ( Methionine hydroxyl) Lowering Ruminal Protease Activity Decreasing Retention Time in Rumen

16. Naturally Protected Proteins Feed UDP % Maize (grain) 53-60 Barley 21( 11-27) Sorghum 52 Bajra 68 Oat grain 14–20 Wheat grain 20–36 Cotton seed meal 41–50 Linseed meal 11–45 Ground nut meal 30 Rapeseed meal 23 Soybean meal 34-42 Sunflower meal 24 Subabul 51 – 70 Feed UDP % Blood meal 76 – 82 Fish meal 71 – 80 Meat meal 53 – 76 Brewers dried 53 Corn gluten 53 Wheat bread 29 Corn silage 27 Rice straw 63 Wheat straw 45 Para grass 52 Cow pea 32 – 45 Berseem 37 – 52 Alfa-Alfa 28 (NRC, 2001 ) ; INRAE

17. Importance of Bypass Protein Required for medium and high lactating and growing animals mainly in early lactation. Increase in Milk production by 10-15 %. Good increase in live weight gain of meat purpose animals. Exposes essential and limiting amino acids directly to Intestine. Reduces Milk Production cost.

18. Why Limit High RUP Proteins in Lactating Cows Animal byproducts tend to reduce feed intake Palatability d ecreased feed intake reduces microbial protein synthesis Plant byproducts may have poor amino acid balance Corn proteins deficient in lysine and Quality of RUP proteins can be variable Protein requirements may have been met First limiting amino acid might not be increased Overestimation of degradation of other supplemental proteins .

19. Comparison of Degradable and Un-degradable Protein Feature Degradable Protein Undegradable Protein Degradation site Rumen Small intestine Degradation products Ammonia and amino acids Amino acids Utilization Microbial protein synthesis Direct amino acid supply Benefits High-quality protein source Essential amino acids Limitations Ammonia toxicity, nitrogen loss Reduced microbial protein synthesis

20. Non-Protein Nitrogenous Substances (NPN) NPN are nitrogen-containing compounds that are not protein. NPN sources Urea Ammonia (NH3) Nitrates (NO3) young grass silage immature root crop

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