Determination of ruminal protein degradation of three forages using in vitro protein fractions and in situprotein degradability characteristics

Abstract

The methods and mathematical models for ruminants recognize that the ruminal protein degradability of forages may differ by various J Dairy Vet Anim Res. 2018;7(4):154-159. 154 AbstractThe objective of this study was to determine the crude protein fractions of selected three forages (A, B 1 , B 2 , B 3 and C) by in vitro Cornell Net Carbohydrate and Protein System (CNCPS) and the crude protein degradability charecteristics by in situ Nylon Bag Technique (NBT). Also, ruminal protein degradabilities were compared according to the feeding levels of ruminant to gain a better understanding of the suitability of these techniques in assessing the forage types. The forages used most commonly in Aegean region were chosen as a feed material: mature alfalfa hay (AH m ), mature grass hay (GH m ), normal maize silage (MS n ) in the study. The soluble protein (SolP), the non-protein nitrogen (NPN, based on SolP%), the neutral detergent insoluble protein (NDIP) and the acid detergent insoluble protein (ADIP) of forages were determined based on CNCPS. Then, the crude protein (CP) fractions, i.e., A=NPN, B 1 =fast, B 2 =intermediate, B 3 =slow and C=not fermented and unavailable to the animal were calculated. In vitro degradable intake protein (DIP) was calculated (based on CP% and g/kg DM) by using in vitro CP fractions according to dry matter intake fed: DIP 1X = at 1x maintenance level of intake, DIP 2x =at 2x maintenance level of intake, and DIP 3x =at 3x maintenance level of intake. Each forage was incubated between 0-72 h in the rumen of three weathers for three times based on NBT. The CP degradation parameters are (a): fraction of CP immediately soluble protein, (b): the fraction of CP insoluble but degradable in the rumen, (c): the rate constant of degradability of fraction (b). Then, the effective protein degradabilities (based on CP% and g/kg DM) are estimated by using the CP degradation parameters as EPD 2 , EPD 5 and EPD 8 assuming rumen outflow rates of 2, 5 and 8 % h -1 , respectively. In conclusion, the DIP 3x values of MS n , AH m and GH m were 75.06, 63.19 and 56.36 % of CP, respectively. In a different order, the EPD 8 values of AH m , MS n and GH m were found 61.16, 55.88 and 33.75 % CP, respectively. AH m had the highest ruminal protein degradability (based on g/kg DM) compared to the other two forages both CNCPS and NBT. Both of the methods are much more suitable for AH m than MS n and GH m , because the differences between DIP 3x and EPD 8 values were found 3.3, 14.2 and 18.7g/kg DM for AH m , MS n and GH m , respectively. Citation: Acar MC. Determination of ruminal protein degradation of three forages using in vitro protein fractions and in situ protein degradability characteristics. J Dairy Vet Anim Res. 2018;7(4):154-159. Citation: Acar MC. Determination of ruminal protein degradation of three forages using in vitro protein fractions and in situ protein degradability characteristics. J Dairy Vet Anim Res. 2018;7(4):154-159. Citation: Acar MC. Determination of ruminal protein degradation of three forages u...

The balance of rumen degradable protein and readily available carbohydrate in sheep rations on in vitro fermentability

“…It is feared that providing feed protein without paying attention to the level of degradation will cause a deficiency in meeting the protein needs of microbes and livestock. In addition, differences in degradation rates vary and depend on the synchronized and comparative level of rumen protein degradation [3 , 4] . If substance N is degraded more quickly than the energy source (carbohydrates), then the ammonia resulting from the degradation of compound N will be transferred to the liver and then recycled to the digestive tract (a small part), where most of it is lost with urine secretion.…”