Vascular Sources of Amino Acids for Milk Protein Synthesis in Goats at Two Stages of Lactation

Mabjeesh, S.J.; Kyle, C.E.; MacRae, J.C.; Hanigan, M.D.; Bequette, B.J.

doi:10.3168/jds.s0022-0302(02)74150-7

Cited by 15 publications

(12 citation statements)

References 24 publications

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“…Previous studies in goats and cows have reported that Arg, a semi-essential AA, plays important roles in the regulation of milk protein synthesis (Mabjeesh et al, 2002;Doepel and Lapierre, 2011). A recent study in bovine mammary epithelial cells (BMEC) also found the addition of Arg to growth medium promoted the synthesis of casein (Wang et al, 2014); similar results were also reported by Zhao et al (2018) in lactating dairy cows.…”

Section: Introductionsupporting

confidence: 57%

Effects of arginase inhibition via jugular infusion of Nω-hydroxy-nor-l-arginine on metabolic and immune indices in lactating dairy cows

Ding

Wang

Shen

et al. 2019

Journal of Dairy Science

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Transformation of Arg to nitric oxide and ornithine (Arg-Orn) constitutes the main route of Arg metabolism in mammals. The primary objective of this work was to determine the effects of inhibiting the Arg-Orn pathway via N ω-hydroxy-nor-l-arginine (nor-NOHA) on health of lactating cows. Furthermore, we also explored the effect of Arg-Orn inhibition on the efficiency of nitrogen utilization to find support for previous research that showed the inhibition of Arg-Orn inhibited milk protein synthesis. Six healthy Chinese Holstein cows of similar body weight (550.0 ± 20 kg), parity (4.0 ± 0), body condition score (3.0 ± 0), milk yield (21.0 ± 1.0 kg), and days in milk (80 ± 2 d) were selected and randomly assigned to 3 treatments in a replicated 3 × 3 Latin square design with 22 d for each period (7 d for infusion and 15 d for washout). The treatments were (1) saline infusion (control); (2) infusion of 125 mg/L of nor-NOHA; and (3) infusion of 125 mg/L of nor-NOHA with 9.42 g/L of Arg. Dry matter intake, apparent digestibility of nutrients, urinary N, N in milk, and blood indices of metabolism and immune function were determined. Compared with the control, the infusion of nor-NOHA had no effect on the concentrations of cholesterol, high-density lipoproteins, IgA, IL-1β, tumor necrosis factor-α, and alanine transaminase. In addition, the dry matter intake, apparent digestibility of N, and the concentration of milk protein N in the Nor-NOHA did not differ from the control; however, the infusion of nor-NOHA and Arg resulted in greater concentrations of high-density lipoprotein, IgA, IL-1β, and tumor necrosis factor-α, and lower concentrations of cholesterol in serum compared with the control. Moreover, the addition of Arg to cows infused with nor-NOHA increased the concentration of nitrate (the indicator of nitric oxide) in serum and was associated with greater milk protein N production due to greater milk yield compared with those infused with nor-NOHA. Overall, the results indicated important roles of Arg in immunity and mammary N utilization, whereas a minor role of the Arg-Orn pathway in these physiologic processes was found.

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Section: Introductionsupporting

confidence: 57%

Effects of arginase inhibition via jugular infusion of Nω-hydroxy-nor-l-arginine on metabolic and immune indices in lactating dairy cows

Ding

Wang

Shen

et al. 2019

Journal of Dairy Science

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“…In goats at early and late lactation, methionine, histidine, threonine, proline, and phenylalanine in milk protein output were not accounted for in estimates of uptake of free AA (Mabjeesh et al, 2002). An in vivo isotope kinetic technique was used to determine the sources of AA for milk protein synthesis in which a long-term (greater than 20 h) i.v.…”

Section: Peptides As a Source Of Aa For The Mammary Glandmentioning

confidence: 99%

BOARD-INVITED REVIEW: Peptide absorption and utilization: Implications for animal nutrition and health

Gilbert

Wong

Webb

2008

Journal of Animal Science

294

209

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Over the last 50 yr, the study of intestinal peptide transport has rapidly evolved into a field with exciting nutritional and biomedical applications. In this review, we describe from a historical and current perspective intestinal peptide transport, the importance of peptides to whole-body nutrition, and the cloning and characterization of the intestinal peptide transporter, PepT1. We focus on the nutritional significance of peptide transport and relate these findings to livestock and poultry. Amino acids are transported into the enterocyte as free AA by a variety of AA transporters that vary in substrate specificity or as di- and tripeptides by the peptide transporter, PepT1. Expression of PepT1 is largely restricted to the small intestine in most species; however, in ruminants, peptide transport and activity is observed in the rumen and omasum. The extent to which peptides are absorbed and utilized is still unclear. In ruminants, peptides make a contribution to the portal-drained visceral flux of total AA and are detected in circulating plasma. Peptides can be utilized by the mammary gland for milk protein synthesis and by a variety of other tissues. We discuss the factors known to regulate expression of PepT1 including development, diet, hormones, diurnal rhythm, and disease. Expression of PepT1 is detected during embryological stages in both birds and mammals and increases with age, a strategic event that allows for the immediate uptake of nutrients after hatch or birth. Both increasing levels of protein in the diet and dietary protein deficiencies are found to upregulate the peptide transporter. We also include in this review a discussion of the use of dietary peptides and potential alternate routes of nutrient delivery to the cell. Our goal is to impart to the reader the nutritional implications of peptide transport and dietary peptides and share discoveries that shed light on various biological processes, including rapid establishment of intestinal function in early neonates and maintenance of intestinal function during fasting, starvation, and disease states.

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“…As the raw materials of milk protein synthesis, some EAA (lysine, methionine, and histidine) elicit regulation on the synthesis of milk protein (Prizant and Barash, 2008;Kim and Wu, 2009). Recently, some studies revealed that Arg, a conditionally essential AA, also has some positive effects on the synthesis of milk protein (Mabjeesh et al, 2002;Doepel and Lapierre, 2011). Some recent studies (Chen et al, 2013;Wu et al, 2016) have demonstrated that the addition of Arg in culture medium increased casein protein synthesis in bovine mammary epithelial cells (BMEC).…”

Section: Introductionmentioning

confidence: 99%

Inhibition of arginase via jugular infusion of Nω-hydroxy-nor-l-arginine inhibits casein synthesis in lactating dairy cows

Ding

Chen

Wang

et al. 2018

Journal of Dairy Science

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A previous in vitro study revealed that Arg elicits positive effects on casein synthesis through alterations of the Arg-ornithine pathway in bovine mammary epithelial cells. The main purpose of this work was to determine the effects of arginase inhibition using N-hydroxy-nor-l-arginine (nor-NOHA) on milk protein synthesis in vivo. Six healthy Chinese Holstein cows with similar body weight (550.0 ± 20 kg; means ± standard deviation), parity (4), body condition score (3.0), milk yield (21.0 ± 1.0 kg), and days in milk (80 ± 2) were selected and randomly assigned to 3 treatments in a replicated 3 × 3 Latin square design with 22 d for each period (7 d for infusion and 15 d for washout). The treatments were (1) control: saline infusion; (2) nor-NOHA: infusion of 125 mg/L of nor-NOHA; (3) nor-NOHA + Arg: infusion of 125 mg/L of nor-NOHA with 9.42 g/L of Arg. The activity of enzymes related to Arg metabolism, milk protein synthesis, and expression of AA transporters was determined. The infusion of nor-NOHA decreased the activity of arginase but had no effect on the activity of ornithine decarboxylase and nitric oxide synthase in serum, and these responses were the same at the gene expression level in mammary gland. In addition, the infusion of nor-NOHA also reduced protein and fat synthesis in milk but had no effect on milk yield. When Arg was infused with nor-NOHA, the activity of total arginase, ornithine decarboxylase, and nitric oxide synthase, and the concentration of casein, protein, and fat in milk did not change compared with the nor-NOHA group, but the milk protein yield, the expression of some Arg transporters (SLC7A5 and SLC7A8), and milk yield increased. Overall, results verified previous in vitro findings indicating that synthesis of casein protein is closely regulated by the Arg-ornithine pathway in bovine mammary gland.

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Vascular Sources of Amino Acids for Milk Protein Synthesis in Goats at Two Stages of Lactation

Cited by 15 publications

References 24 publications

Effects of arginase inhibition via jugular infusion of Nω-hydroxy-nor-l-arginine on metabolic and immune indices in lactating dairy cows

Effects of arginase inhibition via jugular infusion of Nω-hydroxy-nor-l-arginine on metabolic and immune indices in lactating dairy cows

BOARD-INVITED REVIEW: Peptide absorption and utilization: Implications for animal nutrition and health

Inhibition of arginase via jugular infusion of Nω-hydroxy-nor-l-arginine inhibits casein synthesis in lactating dairy cows

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