Effects of in vitro addition of ammonia on the metabolism of <sup>15</sup>N-labelled amino acids in isolated sheep hepatocytes

Mutsvangwa, T.; Buchanan-Smith, J. G.; McBride, B.W.

doi:10.4141/a98-082

Cited by 7 publications

(11 citation statements)

References 12 publications

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“…The data of Lobley et al (1995) demonstrated that an NH 3 load increased oxidation of Leu in sheep, although this response has been attributed to metabolic acidosis in response to NH 4 Cl infusion (Lobley et al, 1996). Our results also contrast the data of Mutsvangwa et al (1999), in which Met deamination was increased with NH 3 loading in vitro.…”

Section: Resultscontrasting

confidence: 81%

“…The use of AA N in ureagenesis may affect the use of AA for protein synthesis. In fact, NH 3 loading increased oxidation of Leu in vivo (Lobley et al, 1995) and Met and Ala in vitro (Mutsvangwa et al, 1996(Mutsvangwa et al, , 1999.…”

Section: Introductionmentioning

confidence: 99%

“…Ala, Glu, Leu, or Phe in vitro (Mutsvangwa et al, 1996(Mutsvangwa et al, , 1997(Mutsvangwa et al, , 1999, suggesting little or no effect of NH 3 loading on AA utilization (Lobley et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

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Ruminal ammonia load affects leucine utilization by growing steers1

Awawdeh

Titgemeyer

McCuistion

et al. 2005

Journal of Animal Science

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Six ruminally cannulated Holstein steers (initial BW = 189 +/- 11 kg) housed in metabolism crates were used in a 6 x 6 Latin square to study effects of ruminal ammonia load on Leu utilization. All steers received a diet based on soybean hulls (2.7 kg of DM/d), ruminal infusions of 200 g of acetate/d, 200 g of propionate/d, and 50 g of butyrate/d, as well as an abomasal infusion of 300 g of glucose/d to provide energy without increasing microbial protein supply and an abomasal infusion of a mixture (238 g/d) of all essential AA except Leu. Treatments were arranged as a 3 x 2 factorial and included Leu (0, 4, or 8 g/d) infused abomasally and urea (0 or 80 g/d) infused ruminally. Abomasal Leu infusion linearly decreased (P < 0.05) both urinary and fecal N excretions and linearly increased (P < 0.05) retained N, but the decreases in urinary N excretion in response to Leu tended (P = 0.07) to be greater, and the increases in retained N in response to Leu were numerically greater in the presence of the urea infusion. Although urea infusions increased (P < 0.05) plasma urea concentrations, urinary N excretions, and urinary urea excretions, retained N also was increased (P < 0.05). The efficiency of deposition of supplemental Leu ranged from 24 to 43% when steers received 0 or 80 g of urea/d, respectively. Under our experimental conditions, increasing ammonia load improved whole-body protein deposition in growing steers when Leu supply was limiting.

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Section: Resultscontrasting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

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Ruminal ammonia load affects leucine utilization by growing steers1

Awawdeh

Titgemeyer

McCuistion

et al. 2005

Journal of Animal Science

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“…However, they have shown that 5-d duodenal ammonia infusions in Holstein-Friesian dairy cows did not significantly change milk yield or milk constituent yields. In vitro studies by Mutsvangwa et al (1999) using isolated sheep hepatocytes and 15 N-labelled amino acids (met, leu, phe) provided evidence that NH 3 detoxification to urea stimulates methionine catabolism, but that leucine and phenylalanine catabolism were not affected. This could imply that in cows experiencing a deficiency in methionine, ammonia detoxification could put a stress on the requirement for methionine and, subsequently, reduce milk yield and/or milk protein.…”

Section: Resultsmentioning

confidence: 99%

Effect of post-ruminal infusion of glutamine on plasma amino acids, milk yield and composition in lactating dairy cows

Plaizier¹,

Walton²,

McBride³

2001

Can. J. Anim. Sci.

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. W. 2001. Effect of post-ruminal infusion of glutamine on plasma amino acids, milk yield and composition in lactating dairy cows. Can. J. Anim. Sci. 81: 229-235. The objectives of this study were to examine the effect of supplying post-ruminal L-glutamine in mid-lactation Holstein dairy cows on plasma amino acid profile, dry matter intake, milk yield and milk composition. The experiment was designed as a 4 × 4 Latin square with four 2-wk periods. Cows were continuously infused post-ruminally with graded levels of L-glutamine (L-Gln) for 5 consecutive days during the second week of each period. During the last 24 h of the infusion, blood plasma was collected every 6 h for the determination of plasma amino acid concentrations. Plasma Gln concentration increased (P < 0.05) with increasing L-Gln daily infusions. Infusion of 0, 100, 200, and 300 g d -1 resulted in blood plasma Gln concentrations of 289.5, 299.2, 356.4 and 386.2 µmol L -1 , respectively. The level of Gln infusion also resulted in a decrease in the blood plasma concentration of phenylalanine, but the concentrations of all other amino acids were not affected. The administration of Gln did not affect dry matter intake, milk yield and milk composition.

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“…In vivo (Lobley et al, 1995) and in vitro (Mutsvangwa et al, 1996(Mutsvangwa et al, , 1999 studies suggested that metabolic ammonia (NH 3 ) loading might lead to inefficient use of dietary AA by metabolically consuming AA to provide α-amino N to support ureagenesis. We recently observed no negative effects of NH 3 loading on protein deposition when Met, Leu, or His limited cattle performance (Awawdeh et al, 2004(Awawdeh et al, , 2005McCuistion et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Excess amino acid supply improves methionine and leucine utilization by growing steers1

Awawdeh

Titgemeyer²,

Schroeder³

et al. 2006

Journal of Animal Science

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In 2 experiments, 6 ruminally cannulated Holstein steers (205 +/- 23 and 161 +/- 14 kg initial BW in Exp. 1 and 2, respectively) housed in metabolism crates were used in 6 x 6 Latin squares to study the effects of excess AA supply on Met (Exp. 1) and Leu (Exp. 2) use. All steers received a diet based on soybean hulls (DMI = 2.66 and 2.45 kg/d in Exp. 1 and 2, respectively); ruminal infusions of 200 g of acetate/d, 200 g of propionate/d, and 50 g of butyrate/d, as well as abomasal infusion of 300 g of glucose/d to provide energy without increasing the microbial protein supply; and abomasal infusions of a mixture of all essential AA except Met (Exp. 1) or Leu (Exp. 2). Periods were 6 d, with 2-d adaptations and 4 d to collect N balance data. All treatments were abomasally infused. In Exp. 1, treatments were arranged as a 2 x 3 factorial, with 2 amounts of l-Met (0 or 4 g/d) and 3 AA supplements (no additional AA, control; 100 g/d of nonessential AA + 100 g/d of essential AA, NEAA + EAA; and 200 g/d of essential AA, EAA). Supplemental Met increased (P < 0.01) retained N and decreased (P < 0.01) urinary N and urinary urea N. Retained N increased (P < 0.01) with NEAA + EAA only when 4 g/d of Met was provided, but it increased (P < 0.01) with EAA with or without supplemental Met. Both AA treatments increased (P < 0.01) plasma urea and serum insulin. Plasma glucose decreased (P = 0.03) with supplemental Met. In Exp. 2, treatments were arranged as a 2 x 3 factorial with 2 amounts of L-Leu (0 or 4 g/d) and 3 AA supplements (control, NEAA + EAA, and EAA). Supplemental Leu increased (P < 0.01) retained N and decreased (P < 0.01) urinary N and urinary urea N. Both AA treatments increased (P < 0.01) retained N, and they also increased (P < 0.01) urinary N, urinary urea N, and plasma urea. Serum insulin increased (P = 0.06) with supplemental Leu and tended (P = 0.10) to increase with both AA treatments. Supplementation with excess AA improved Met and Leu use for protein deposition by growing cattle.

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Effects of in vitro addition of ammonia on the metabolism of ¹⁵N-labelled amino acids in isolated sheep hepatocytes

Cited by 7 publications

References 12 publications

Ruminal ammonia load affects leucine utilization by growing steers1

Ruminal ammonia load affects leucine utilization by growing steers1

Effect of post-ruminal infusion of glutamine on plasma amino acids, milk yield and composition in lactating dairy cows

Excess amino acid supply improves methionine and leucine utilization by growing steers1

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Effects of in vitro addition of ammonia on the metabolism of 15N-labelled amino acids in isolated sheep hepatocytes

Cited by 7 publications

References 12 publications

Ruminal ammonia load affects leucine utilization by growing steers1

Ruminal ammonia load affects leucine utilization by growing steers1

Effect of post-ruminal infusion of glutamine on plasma amino acids, milk yield and composition in lactating dairy cows

Excess amino acid supply improves methionine and leucine utilization by growing steers1

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Product

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Effects of in vitro addition of ammonia on the metabolism of ¹⁵N-labelled amino acids in isolated sheep hepatocytes