In situ ruminal degradation of amino acids and in vitro protein digestibility of undegraded CP of dried distillers’ grains with solubles from European ethanol plants

Abstract

The objectives of this study were to compare the in situ ruminal degradation of CP and amino acids (AAs) of dried distillers' grains with solubles (DDGS), and to estimate intestinal digestibility (ID) of undegradable crude protein (UDP) with the in vitro pepsinpancreatin solubility of CP (PPS), using either DDGS samples (DDGS-s) or DDGS residues (DDGS-r) obtained after 16 h ruminal incubation. Thirteen samples originating from wheat, corn, barley and blends were studied. Lysine and methionine content of DDGS-s varied from 1.4 to 4.0 and 1.3 to 2.0 g/16 g N, respectively. The milk protein score (MPS) of DDGS-s was low and ranged from 0.36 to 0.51, and lysine and isoleucine were estimated to be the most limiting AAs in DDGS-s and DDGS-r. DDGS-r contained slightly more essential AAs (EAAs) than did the DDGS-s. Rumen degradation after 16 h varied from 44% to 94% for CP, from 39% to 90% for lysine and from 35% to 92% for methionine. Linear regressions showed that the ruminal degradation of individual AAs can be predicted from CP degradation. The PPS of DDGS-s was higher than that of DDGS-r and it varied from 70% to 89% and from 47% to 81%, respectively. There was no significant correlation between the PPS of DDGS-s and PPS of DDGS-r ( R 2 = 0.31). The estimated intestinally absorbable dietary protein (IADP) averaged 21%. Moderate correlation was found between the crude fibre (CF) content and PPS of DDGS-r ( R 2 = 0.43). This study suggests an overestimation of the contribution of UDP of DDGS to digestible protein supply in the duodenum in some currently used protein evaluation systems. More research is required and recommended to assess the intestinal digestibility of AAs from DDGS.

Growth Performance and Carcass Traits Responses to Dried Distillers’ Grain with Solubles Feeding of Growing Awassi Ram Lambs

“…The influences of inclusion of DDGS in the diets of ruminants were not consistent with results of existing studies. Tanaka et al [15] and Westreicher-Kristen et al [16] reported similar DM intake when DDGS was fed to dairy cows at levels of more than 200 g/kg of dietary DM or at levels of 100 or 150 g/kg DM, as reported by Leonardi et al [17], when fed to lambs at levels of 75 and 150 g/kg DM [2] or when fed to ewes at 200 and 300 g/kg DM [1]. Conversely, Janicek et al [18] reported an increase in DM intake when dairy cows where fed DDGS at levels of 0, 100, 200, and 300 g/kg DM.…”

In vitro microbial protein synthesis, ruminal degradation and post‐ruminal digestibility of crude protein of dairy rations containing Quebracho tannin extract

“…This incubation time was chosen as a universal standard that represents a rumen outflow rate of 6.3%/hr which corresponds to a feeding level of approximately 2.5 × maintenance (AFRC, ). Incubations followed the procedure described by Westreicher‐Kristen, Steingass, and Rodehutscord (), using four nylon bags per ration for the determination of zero time disappearance (0 hr) and ten nylon bags per ration and heifer for ruminal incubation.…”

Replacing maize silage plus soybean meal with red clover silage plus wheat in diets for lactating dairy cows

“…Hence, in the current study, it was not possible to differentiate whether the reduced milk protein concentration was caused by reduced MCP synthesis alone (based on PD excretion) or in combination with reduced RUP flow to the intestine. Additionally, because the intestinal digestibility of the RUP fraction is a prerequisite for calculating the AA supply to the cow (Westreicher-Kristen et al, 2013), this should be considered as a possible influence on the supply of available protein for milk protein synthesis. Therefore, this possible RUP effect remains unsolved and needs further research.…”