Effects of dietary concentrate level on nutrient absorption, liver metabolism, and urea kinetics of beef steers fed isonitrogenous and isoenergetic diets.

Huntington, G. B.; Zetina, Elinor J.; Whitt, J. M.; Potts, William John

doi:10.2527/1996.744908x

Cited by 66 publications

(65 citation statements)

References 23 publications

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“…the forage to concentrate ratio) and intake. Huntington et al (1996) reported that, when fed diets with 20% or less concentrate, steers recycled 90% of hepatic urea production; the percentage of recycled urea decreased to 64 with 63% of the diet as concentrates, and to 51% when diets with 90% concentrate were fed. Increased urea recycling to the GIT may improve the overall effi ciency of N utilization for maintenance and production.…”

Section: Manipulating Pathways Of Urea Recyclingmentioning

confidence: 99%

Ammonia production, ammonia absorption, and urea recycling in ruminants. A review

Tan¹,

Murphy²

2004

J. Anim. Feed Sci.

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Relevant research on ammonia production, ammonia absorption, and urea recycling in ruminants was reviewed. Ammonia production and utilization in the rumen and post-ruminal digestive tracts are described in detail. Absorption of ammonia into portal-drained viscera, ammonia detoxifi cation and urea synthesis in the liver, and urea degradation in the gastrointestinal tract are then discussed. The factors of affecting urea recycling and its pathways are also analysed. Suggested future research should focus on urea recycling dynamics and improvement of protein conversion effi ciency, and on the development of an integrated mechanistic model to describe the digestion and metabolism of nitrogen-containing compounds in ruminants fed practical diets.

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Section: Manipulating Pathways Of Urea Recyclingmentioning

confidence: 99%

Ammonia production, ammonia absorption, and urea recycling in ruminants. A review

Tan¹,

Murphy²

2004

J. Anim. Feed Sci.

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“…This is due to the protein content of the hay harvested at 15 days of growth, which resulted in a higher amount of digestibility of crude protein and therefore a larger amount of nitrogen for the rumen. It is important to highlight that NH 3 -N contents directly relate to dietary CP amounts (Freeman et al, 1992;Huntington et al, 1996;Thivierge et al, 2002), a fact observed in this trial. Furthermore, it is worth mentioning that the activity of cellulolytic microorganisms is highly dependent on ruminal NH 3 -N concentration.…”

Section: Ruminal Fermentation Parametersmentioning

confidence: 99%

Methane Emission of Cattle Fed Urochloa brizantha Hay Harvested at Different Stages

Nascimento¹,

Berndt²,

Solórzano³

et al. 2015

JAS

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The objective of this trial was to assess the methane emission rate, as well as the digestibility and ruminal fermentation parameters in animals fed Urochloa brizantha hay harvested at different stages of growth. Six Nellore rumen-cannulated steers (402.0 ± 51.62 kg) were assigned to a replicated 3×3 Latin square (18 experimental units). Treatments differed according to three growth stages of the forage: 15 -hay with 15 days of growth, 45 -hay with 45 days of growth and 90 -hay with 90 days of growth. Each experimental period lasted 21 days. From the 8 th day, feces were sampled during 5 days to determine apparent total digestibility of dry matter and its fractions. Beginning on the 13 th day and running for 7 days, methane production was evaluated using the sulfur hexafluoride (SF 6 ) tracer technique. On the 20 th day, ruminal fluid was sampled prior to and after 2, 4, 6, 8 and 10 hours post-morning feeding for evaluating pH, ammonia-N and short-chain fatty acids (SCFA). As the stage of forage growth for harvesting advanced in days, the digestibility coefficient of crude protein decreased and non-fibrous carbohydrate values increased. Methane production was affected not only by the stage of forage growth, but also by quality of its conservation after harvesting. There were significant differences among treatments when methane was expressed in g kg -1 DMI, g kg -1 OMI, % GE and % DE, with non-linear effect. The stage of forage growth did not influence ruminal pH, total concentration or molar proportion of SCFA, but decreased NH 3 -N concentration.

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“…With increasing grain in the diet, there is also an increase in the amount of glucose absorbed postruminally (Huntington et al 1996). Taken together, these results indicate altering the forage:concentrate ratio likely results in different substrates available for absorption, for interaction with gastrointestinal epithelial cells, and for interaction with post-absorptive tissues.…”

Section: Discussionmentioning

confidence: 83%

Pancreatic mass, cellularity, and α-amylase and trypsin activity in feedlot steers fed diets with increasing corn silage inclusion

Swanson¹,

Kelly²,

Wang³

et al. 2008

Can. J. Anim. Sci.

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. W. 2008. Pancreatic mass, cellularity, and a-amylase and trypsin activity in feedlot steers fed diets with increasing corn silage inclusion. Can. J. Anim. Sci. 88: 703Á709. Twentyfour yearling beef steers (initial BW 053595.0 kg), predominately of Angus breeding, were used in a randomized complete block design to determine the effect of dietary inclusion of corn silage on pancreatic cellularity, mass, and a-amylase and trypsin activity. Using calan gates, steers were individually fed diets containing 20, 40, 60, or 80% corn silage (DM basis) with the rest of the diet made up of concentrate. Diets were formulated to maintain a constant CP:ME (g Mcal ) and were fed at 2.1 )NE m requirement. After 28 d on treatment, the two heaviest steers from each treatment were slaughtered per week and pancreata collected. Pancreatic weight (g and g kg(1 BW) and content (kU and U kg (1 BW) of a-amylase activity did not differ among dietary treatments. Concentration (U g(1 ) of pancreatic a-amylase decreased (P00.03) with increasing corn silage inclusion. Pancreatic DNA and RNA content (g and mg kg(1 BW) increased linearly (P 50.04) with increasing corn silage inclusion. The content of pancreatic trypsin activity responded cubically (P00.03). These data indicate that increasing corn silage inclusion does not influence total pancreatic a-amylase activity and that cell number may influence pancreatic a-amylase concentration. Ces re´sultats indiquent qu'augmenter la quantite´d'ensilage de maı¨s dans la ration n'exerce aucune influence sur l'activite´totale de la a-amylase pancre´atique mais que le nombre de cellules pourrait agir sur la concentration de cette enzyme.Mots clé s: Mots cle´s: Bovins de boucherie, pancre´as, a-amylase, trypsine, fourrage, concentreT he pancreas produces enzymes responsible for the digestion of nutrients in the small intestine. Pancreatic a-amylase and trypsin are responsible for the partial hydrolysis of starch and protein, respectively, in the small intestine. Pancreatic exocrine function is influenced by nutritional as well as genetic factors Swanson and Miller 2008). In high concentrate feedlot diets, significant amounts of dietary starch reach the small intestine (Theurer 1986) where there may be limitations in starch digestion due to inadequate a-amylase secretion Harmon et al. 2004). Dietary forage:concentrate may be an important regulator of pancreatic exocrine function. Data suggest that pancreatic content of aamylase activity decreases in cattle fed a high grain diet vs. those fed a high forage diet at similar energy intakes (Kreikemeier et al. 1990;Harmon 1992). However, when dietary metabolizable protein intake was fed at similar intakes in lambs, content of pancreatic a-amylase activity was not influenced by increased starch concenAbbreviations: ADF, acid detergent fibre; BW, body weight; DM, dry matter; ME, metabolizable energy; NDF, neutral detergent fibre; NE m , net energy for maintenance For personal use only.

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Effects of dietary concentrate level on nutrient absorption, liver metabolism, and urea kinetics of beef steers fed isonitrogenous and isoenergetic diets.

Cited by 66 publications

References 23 publications

Ammonia production, ammonia absorption, and urea recycling in ruminants. A review

Ammonia production, ammonia absorption, and urea recycling in ruminants. A review

Methane Emission of Cattle Fed Urochloa brizantha Hay Harvested at Different Stages

Pancreatic mass, cellularity, and α-amylase and trypsin activity in feedlot steers fed diets with increasing corn silage inclusion

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