In situ intestinal digestibility of dry matter and crude protein of cereal grains and rapeseed in sheep

Abstract

-The ruminal degradation and intestinal digestibility (ID) of dry matter (DM) and crude protein (CP) of different feed samples were measured in two trials by using nylon bag and rumen outflow rate techniques in three wethers cannulated in the rumen and in the duodenum. In trial 1, three samples of grains of wheat, barley, and corn treated by cooking (TW, TB, and TC, respectively) were studied together with a sample of untreated corn grains (CG) of different origin. In trial 2, these studies were carried out on a sample of rapeseed (RS) and on a mix of this same sample and rapeseed meal (in proportions 70: 30) treated by cooking (TR). In both trials, the animals were fed at the same intake level (40 g DM·kg -1 LW 0.75 ) with 2:1 (DM basis) forage to concentrate diets. Rumen degradation rates of DM were high in the treated cereals (between 11.0 and 14.2%·h ) and low in the CG (6.35%·h -1 ), whereas for CP these rates were low in all cereals. For DM, in all cereals, ID decreased linearly as the ruminal incubation time increased. The values of intestinal effective digestibility (IED), calculated from these functions and from the rumen outflow, were respectively: 86.4, 62.1, 51.5, and 67.9%. For CP, ID was unaffected by the ruminal incubation time in corn samples, whereas in TW and TB a reduction of these values was only observed for the time of 48 h. The values of IED of CP for CG, TW, TB and TC were: 82.6, 88.9, 82.5, and 91.6%, respectively. Rumen degradation rates of the RS and TR samples were 8. 35 and 8.23%·h -1 for DM and 12.0 and 9.59%·h -1 for CP. In RS, the ID of DM and CP showed a downward trend with an increase of the ruminal incubation time, as modelled according to an exponential function. This same trend was observed for TR after a lag period estimated at 7.53 and 6.51 h for DM and CP, respectively. The values of IED of RS and TR were respectively 56.5 and 50.8% for DM and 71.9 and 80.1% for CP. These same results were also determined by a simplified method using a sample pooled to be representative of the rumen outflow of undegraded feed. The respective values for RS and TR were 54.8 and 51.6 for DM and 65.8 and 78.9% for CP. This method seems to be a promising technique to estimate IED, although more studies are needed to improve its accuracy.cereal / rapeseed / intestinal effective digestibility / in situ Reprod. Nutr. Dev. 43 (2003) 29-40 29

In situ evaluation of the protein value of wheat grain corrected for ruminal microbial contamination

“…Apparent values of IED of DM were higher than those obtained by González et al 4 for a cooked wheat sample (62.1%). However, this last sample had an ADL/ADF ratio 2.5 times higher.…”

Estimating In Situ Effective Crude Protein Degradability with Cornell Net Carbohydrate and Protein System Parameters in Energy-Rich Feedstuffs for Ruminants

“…In situ Nylon Bag Method (NBM) is the most widely used research approach for measuring ruminal CP degradation [6] . This method also requires rumen cannulated animals, but it is relatively simple compared to in vivo method [1,7] . The CNCPS estimates the degradable proteins of the feedstuff using five CP fractions based on solubility in protein precipitant agents, buffer and detergent solutions: A represents the soluble non-protein nitrogen (NPN), B 1 (soluble true protein) is the albumins and globulins, B 2 is the most albumins and glutelins, B 3 is the prolamins, extension proteins and heat denatured proteins, and C is the unavailable N (N bound to lignin) [8][9][10] .…”

Effect of extrusion on in situ ruminal protein degradability and in vitro digestibility of undegraded protein from different feedstuffs

“…1,17 The in situ mobile bag technique, initially proposed by Hvelplund,18 has also been often used to determine the intestinal digestibility of RUP, 3,10,19,20 but it requires the use of animals cannulated in the duodenum, making the method unsuitable for routine feed analysis. As an alternative, the threestep in vitro procedure proposed by Calsamiglia and Stern 21 is a rapid, reliable and cheap method for estimating intestinal digestion of protein in ruminants and can be a useful procedure for evaluating quality of protein.…”