Apparent and true digestibility of protein and amino acids in the small intestine of sheep as related to the duodenal passage of protein and non-protein dry matter

The experiment was carried out on 10 bulls of about 120 kg live weight equipped with rumen cannulas and re-entrant cannulas in the proximal duodenum and terminal ileum. The bulls were given a diet of maize whole plant meal, potato starch and mineral mixture. The diet was supplemen ted for group I with groundnut oilmeal (60% of dietary N), for group II with groundnut oilmeal (10.5% dietary N) and urea (48% of dietary N), and for group III with urea (58% dietary N). Diets I, II and III contained, according to the INRA system, 15% CP in DM; 234, 196, 186 g PDIN; 227, 158, 145 g PDIE, and 2.14, 2.11, 2.11 UFV, respectively. Daily feed intake was 2.25 kg.The ammonia-N level in the rumen fluid 2 h after feeding was 8.2, 15.1 and 24.5 mg/100 ml in animals of groups I, II and III, respectively. The amount of N entering the duodenum was 20.1; 22.1 and 18.0 g, leaving the ileum 9.7, 10.4 and 7.3 g/day/kg of feed intake, in the respective groups. The apparent duodenal-N absorption from the small intestine was 52, 53 and 59%, respectively.Total amino acids (g/day/kg feed) ingested with feed equalled 128, 62 and 49; entering the duodenum 107, 113 and 92; leaving the ileum 43, 48 and 32; absorbed from the small intestine 64, 65 and 60 in groups I, II and III, respectively. The apparent intestinal absorption of most amino acids entering the duodenum was from 50 to 70% in all groups, but absorption of cysteine was markedly lower, 25-40%. The amount of lysine absorbed from the small intestine in group I was similar to the amount ingested, but exceeded this amount by 2.4 and 3 times in groups II and III. Absorption of methionine was two times higher, indicating considerable conversion of dietary N in group II and III into microbial amino acids.

Section: Discussionsupporting

confidence: 83%

Nitrogen conversion and apparent intestinal amino acid absorption in young bulls fed isonitrogenous diets with different nitrogen sources

Kowalczyk¹,

Żebrowska²

1998

“…The values of 34 % (Group 1) and 36%o (Group 2) are similar to those of Lebzien and Rohr (1994), who estimated that at the ileum of cows, the endogenous N portion was 40%o of the total amino acid N. Voigt et al (1996), Van Bruchem et al (1997) and Lammers-Wienhoven et al (1998) estimated a higher endogenous proportion of total N (48%) for 55 kg sheep. According to Van Bruchem et al (1985, 1989 and Oosting et al (1995) 50-75 %o of ileal N is of endogenous origin. Their experiments were carried out on 60-70 kg sheep.…”

Section: Discussionmentioning

confidence: 99%

“…The increase in endogenous N from the duodenum to the ileum is caused by continuous N secretion during passage through the intestinal tract (Ben-Ghedalia et al, 1974;Van Bruchem et al, 1989; Lebzien and Rohr, 1994).…”

Section: Discussionmentioning

confidence: 99%

Studies on N-metabolism in different gastrointestinal sections of sheep using the digesta exchange technique. 2. Passage of endogenous nitrogen

Sandek¹,

Krawielitzki²,

Kowalczyk³

et al. 2001

Using a combination of fistulation and the 15 N isotope technique, the flow rates of endogenous N secreted postruminal into different sections of the digestive tract were estimated in growing sheep by digesta exchange between 15 N-labelled and unlabelled animals. To investigate the influence of fibre (CF) on these flow rates the estimations were made on two groups that received approximately isonitrogenous diets (16% CP in DM ) differing in crude fibre content (Group 1: 14.7%>, Group 2:24.9% CF in DM).

“…Voigt et al (1996) and Van Bruchem et al (1997) demonstrated a high correlation between the passage rate of ileal NDF and that of ileal endogenous protein N in sheep. Furthermore, Van Bruchem et al (1989) reported that the passage of non-protein dry matter through the small intestine strongly influenced endogenous protein release in the small intestine. The studies of Zebrowska and Kowalczyk (1991) showed an infusion of cellulose into the small intestine to increase the secretion of total N but not that of urea N. Thus, in small intestine the passage of CF increases the N secretion.…”

Section: Discussionmentioning

confidence: 99%

Studies on N-metabolism in different gastrointestinal sections of sheep using the digesta exchange technique. 3. N secretion and reabsorption

Sandek¹,

Krawielitzki²,

Kowalczyk³

et al. 2002

Using a combination of fistulation, l5 N isotope technique and digesta exchange between labelled and unlabelled sheep, the flow rates of digesta (Sandek et al., 2001a) and the flow rates of endogenous N (Sandek et al., 2001b) were previously estimated. On the basis of these data N reabsorption in the stomachs, the small and large intestine as well as N secretion in these three sections were calculated and differences caused by variations in the crude fibre intake of the two feeding groups (Group 1: 89.7 g/d, Group 2: 119.4 g/d) were estimated.Net N secretion into the forestomachs and abomasum varied considerably between the individual experiments (0.6-2.7 g N/d) but did not show clear differences between the groups.