Feed Restriction Induces Pyruvate Carboxylase but not Phosphoenolpyruvate Carboxykinase in Dairy Cows

Velez, J.C.; Donkin, Shawn S.

doi:10.3168/jds.s0022-0302(05)72974-x

Cited by 104 publications

(112 citation statements)

References 41 publications

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“…As in our study, Velez and Donkin (2005) found no significant differences in gene expression of PEPCK during a study in dairy cows with a dietary restriction of 50% of ad libitum feeding. Our results show that the increased PEPCK mRNA concentrations in the Merino breed have no consequences on gluconeogenesis, suggesting an apparent downgrading concerning the activity on this enzyme in this breed.…”

Section: Discussionsupporting

confidence: 56%

Gene expression of regulatory enzymes involved in the intermediate metabolism of sheep subjected to feed restriction

Harten

Brito

Almeida

et al. 2013

Animal

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The effect of feed restriction on gene expression of regulatory enzymes of intermediary metabolism was studied in two sheep breeds (Australian Merino and Dorper) subjected to two nutritional treatments: feed restriction (85% of daily maintenance requirements) and control (ad libitum feeding), during 42 days. The experimental animals (ram lambs) were divided into four groups, n 5 5 (Australian Merino control (MC), Australian Merino Restriction (MR), Dorper control (DC) and Dorper Restriction (DR)). After the trial, animals were sacrificed and samples were taken from liver tissue to quantify glucose levels and gene expression of relevant intermediary metabolism enzymes (phosphofructokinase (PFK), pyruvate kinase (PK), phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, glucose-6-phosphatase, glycogen synthase (GS), fatty acid synthase (FAS), glutamate dehydrogenase (GDH) and carbamoyl phosphate synthase (CPS)) through real-time PCR. During the experimental period, the MR animals lost 12.6% in BW compared with 5.3% lost by the Dorper lambs. MC and DC rams gained, respectively, 8.8% and 14% during the same period. Within the Dorper breed, restricted feed animals revealed a significant decrease over controls in the transcription of PFK (1.95-fold) and PK (2.26-fold), both glycolytic enzymes. The gluconeogenesis showed no change in the feed restricted animals of both breeds. DR feed group presented a significant decrease over the homologous Merino sheep group on GS. In both experimental breeds, FAS mRNA expression was decreased in restricted feed groups. GDH expression was decreased only in the DR animals (1.84-fold) indicating a reduced catabolism of amino acids in these animals. Finally, CPS was significantly (P , 0.05) higher in the Dorper sheep, indicating a facilitated urea synthesis in this breed. These results indicate a better adaptation of metabolic intermediate regulatory enzymes and hepatic glucose production of Dorper sheep to feed restriction concurring with the BW results in the experimental groups. ImplicationsThe relevant negative impact in livestock production due to seasonal dry periods within tropical and arid climate regions highlights the need to understand genetic and metabolic adaptation mechanisms to periodical feed restriction. Our results concerning changes in BW and genomic expressions of intermediary metabolism regulatory enzymes of ram lambs of Dorper and Australian Merino breeds subjected to ad libitum and to 85% maintenance energy requirements show that Dorper have a better adaptation to feed restriction than the Merino sheep. Our findings can contribute to future research guidelines leading to improved genetic selection toward livestock adaptation to harsh environments.

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Section: Discussionsupporting

confidence: 56%

Gene expression of regulatory enzymes involved in the intermediate metabolism of sheep subjected to feed restriction

Harten

Brito

Almeida

et al. 2013

Animal

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“…In the present study, the likely mobilization of body tissues to provide the mammary gland with fatty acids for milk fat synthesis was confirmed by a corresponding increase in plasma NEFA (Figure 7) during FR. Indeed, plasma NEFA have been shown to reflect mobilization of body reserves in cattle (Chelikani et al, 2004) and sheep (Velez and Donkin, 2005;Chilliard et al, 2007).…”

Section: Milk Yield and Compositionmentioning

confidence: 99%

Effects of short-term feed restriction on milk yield and composition, and hormone and metabolite profiles in mid-lactation Sarda dairy sheep with different body condition score

Pulina

Nudda

Battacone

et al. 2012

Italian Journal of Animal Science

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“…Considering the limited absorption of glucose, and the similar whole body glucose requirements in ruminants and monogastrics (Lindsay, 1981), ruminants rely on hepatic gluconeogenesis for 85% of their whole body glucose turnover (Ortigues-Marty et al, 2003a). Glucose is synthesized from three carbon precursors, propionate (for up to 50% to 70%; Veenhuizen et al, 1988;Bergman, 1990) (Velez and Donkin, 2005). Strong interactions exist between ketogenic and glucogenic metabolism in the liver.…”

Section: Metabolism Of Vfa and Glucose By Portal-drained Visceramentioning

confidence: 99%

Carbohydrate quantitative digestion and absorption in ruminants: from feed starch and fibre to nutrients available for tissues

Nozière

Ortigues-Marty

Loncke

et al. 2010

Animal

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Carbohydrates are the main source of energy in ruminants. Their site, extent and kinetics of digestion highly impact the amount and profile of nutrients delivered to peripheral tissues, and the responses of the animal, i.e. ingestion, efficiency of production, N and methane excretion, quality of products and welfare. Development of multi-objective feed evaluation systems thus requires a more integrated quantitative knowledge on carbohydrate digestion and yield of terminal products, as well as on their metabolism by splanchnic tissues. The objective of this paper is to review (i) quantitative knowledge on fibre, starch and sugar digestion, volatile fatty acids (VFA) and glucose production and splanchnic metabolism and (ii) modelling approaches which aim at representing and/or predicting nutrient fluxes in the digestive tract, portal and hepatic drainage. It shows that the representation of carbohydrate digestion and VFA yield is relatively homogeneous among models. Although published quantitative comparisons of these models are scarce, they stress that prediction of fibre digestion and VFA yield and composition is still not good enough for use in feed formulation, whereas prediction of microbial N yield and ruminal starch digestion seems to be more satisfactory. Uncertainties on VFA stoichiometric coefficients and absorption rates may partly explain the poor predictions of VFA. Hardly any mechanistic models have been developed on portal-drained viscera (PDV) metabolism whereas a few exist for liver metabolism. A qualitative comparison of these models is presented. Most are focused on dairy cows and their level of aggregation in the representation of nutrient fluxes and metabolism highly differs depending on their objectives. Quantitative comparison of these models is still lacking. However, recent advances have been achieved with the empirical prediction of VFA and glucose production and fluxes through PDV and liver based on the current INRA feed evaluation system. These advances are presented. They illustrate that empirical prediction of ruminal VFA and intestinal glucose production can be evaluated by comparison with measured net portal net fluxes. We also illustrate the potential synergy between empirical and mechanistic modelling. It is concluded that concomitant empirical and mechanistic approach may likely help to progress towards development of multi-objective feed evaluation systems based on nutrient fluxes.

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Feed Restriction Induces Pyruvate Carboxylase but not Phosphoenolpyruvate Carboxykinase in Dairy Cows

Cited by 104 publications

References 41 publications

Gene expression of regulatory enzymes involved in the intermediate metabolism of sheep subjected to feed restriction

Gene expression of regulatory enzymes involved in the intermediate metabolism of sheep subjected to feed restriction

Effects of short-term feed restriction on milk yield and composition, and hormone and metabolite profiles in mid-lactation Sarda dairy sheep with different body condition score

Carbohydrate quantitative digestion and absorption in ruminants: from feed starch and fibre to nutrients available for tissues

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