Low-Protein Diets Decrease Porcine Nitrogen Excretion but with

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Agricultural and Environmental Chemistry

Low-Protein Diets Decrease Porcine Nitrogen Excretion but with Restrictive Effects on Amino Acid Utilization Liuting Wu, Xiangxin Zhang, Zhiru Tang, Yunxia Li, Tiejun Li, Qingqing Xu, Jifu Zhen, Feiru Huang, Jing Yang, Cheng Chen, Zhaoliang Wu, Mao Li, Jiajing Sun, Jinchao Chen, Rui An, Shengjun Zhao, Qingyan Jiang, Weiyun Zhu, Yulong Yin, and Zhihong Sun J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.8b03299 • Publication Date (Web): 09 Jul 2018 Downloaded from http://pubs.acs.org on July 22, 2018

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Journal of Agricultural and Food Chemistry

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Running title: Low-protein diets restrict optimal AA usage in pigs

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Title: Low-Protein Diets Decrease Porcine Nitrogen Excretion but with Restrictive

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Effects on Amino Acid Utilization

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Authors: Liuting Wu,† Xiangxin Zhang,†,△ Zhiru Tang,†,△ Yunxia Li,‡ Tiejun Li,§ Qingqing

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Xu,† Jifu Zhen,† Feiru Huang,ǁ Jing Yang,† Cheng Chen,† Zhaoliang Wu,† Mao Li,† Jiajing

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Sun,† Jinchao Chen,† Rui An,† Shengjun Zhao,⊥ Jiang Qingyan,*,# Weiyun Zhu,*,¶ Yulong

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Yin,*,§ and Zhihong Sun*,†

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Affiliations:

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†

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Technology, Southwest University, Chongqing 400715, P. R. China.

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‡

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China.

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§

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P. R. China.

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ǁ

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430070, P. R. China.

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Laboratory for Bio-feed and Molecular Nutrition, College of Animal Science and

Institute of Animal Nutrition, Sichuan Agricultural University, Chengdu 611130, P. R.

Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Changsha 410125,

College of Animal Science and Technology, Huazhong Agricultural University, Wuhan

⊥

School of Animal Science and Nutritional Engineering, Wuhan Polytechnic University, 1

ACS Paragon Plus Environment


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Wuhan 430023, P. R. China.

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#

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510642, P. R. China.

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¶

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210095, P. R. China.

College of Animal Science and Technology, Huanan Agricultural University, Guangzhou

College of Animal Science and Technology, Nanjing Agricultural University, Nanjing

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△

Equally to first author.

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*

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*

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*

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*

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*

Corresponding authors Tel.: +86-20-85281547. Fax: +86-20-85281547. E-mail: [email protected] (Q. Y. J.). Tel.: +86-25-84395366. Fax: +86-25-84395366. Email: [email protected] (W. Y. Z.). Tel.: +86-731-84615204. Fax: +86-731-84612685. Email: [email protected] (Y. L. Y.). Tel.: +86-23-68251196. Fax: +86-23-68251196. Email:[email protected] (Z.H.S.).

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ABSTRACT

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Reducing dietary crude protein (CP) intake effectively decreases nitrogen excretion in

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growing-finishing pigs but at the expense of poor growth when dietary CP content is

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reduced by ≥ 3%. In this study, we investigated the main disadvantages of low-protein

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diets supplemented with lysine, methionine, threonine, and tryptophan in pigs. First,

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changes in the nitrogen balance in response to differences in dietary CP content (18%,

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15%, and 13.5%) were investigated in barrows (40 kg). Then, barrows (40 kg) surgically

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fitted with catheters in the mesenteric vein, portal vein, hepatic vein, and carotid artery

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were used to investigate changes in amino acid (AA) metabolism in the portal-drained

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viscera and liver in response to differences in dietary CP content. The results showed that

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low-protein diets reduced fecal and urinary nitrogen excretion (P < 0.05) meanwhile

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resulted in significant decreases in nitrogen retention (P < 0.05). Moreover, a reduction in

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the dietary CP content from 18% to 13.5% resulted in decreases in the net portal fluxes of

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NH3, glycine, and alanine, as well as in the urea production in the liver (P < 0.05),

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whereas their values as a percentage of nitrogen intake did not decline (P > 0.05). The net

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portal fluxes of nonessential AA (NEAA) were reduced in the low-protein diet groups (P
85% of their 8


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pre-surgery feed intake for ≥ 2 days.

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After recovery from surgery, the barrows were randomly assigned to receive one of the

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three dietary treatments: 18% CP (control), 15% CP, and 13.5% CP (Table 1). The

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experimental period lasted for 7 days. The feed supplied to each pig daily (45 g/kg body

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weight for all groups) was equally divided into three meals, given at 0800, 1400, and 2000

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throughout the experimental period, including the day of blood sampling. On the final day,

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a priming dose of PAH solution (15 mL, 15 mg/mL) was administered through the

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mesenteric vein at 0730, followed by a constant infusion of PAH solution at a rate of 0.8

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mL/min. Sixty minutes after the priming dose (at 0830), blood samples of 5 mL each were

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collected from the portal vein, carotid artery, and hepatic vein, and this was repeated at

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1000, 1200, 1430, and 1730. Sodium heparin solution (100 IU/mL) was used as an

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anticoagulant. Samples were cooled on ice and transferred to the laboratory for

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centrifugation at 1500 × g at 4 °C for 20 min. For each pig, the plasma samples taken from

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each site at the different time points (0830, 1000, 1200, 1430, and 1730) were pooled. The

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mixed plasma was used to measure the concentrations of PAH, AA, urea, and NH3. The

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concentration of plasma PAH was determined using a method described previously.21,28 The

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portal vein plasma flow (PVPF; mL/min) and hepatic vein plasma flow (HVPF; mL/min)

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were calculated using the following equations:

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PVPF = Ci × IR/(PAHpv – PAHa)

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HVPF = Ci × IR/(PAHhv – PAHa) 9



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where Ci is the concentration of infused PAH solution (mg/mL); IR is the infusion rate

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(mL/min) of PAH; and PAHpv, PAHhv, and PAHa are the PAH concentrations (mg/mL) in

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the portal vein, hepatic vein, and carotid artery, respectively. Hepatic artery plasma flow

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(HAPF; mL/min) was then calculated as: HAPF = HVPF (mL/min) – PVPF (mL/min).

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For free AA analysis, frozen plasma samples were thawed at 4 °C. Plasma protein

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precipitation was carried out as follows. Briefly, 1 mL of sample and 2.5 mL of 7.5 % (w/v)

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trichloroacetic acid solution were mixed thoroughly and centrifuged at 12000 × g and 4 °C

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for 15 min. The supernatant was collected and analyzed for AA by GC-MS using the

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isotope dilution method described by Calder et al.36 Analysis of NH3 was performed within

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2 h after blood collection. The procedures for determining urea and NH3 have been

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described previously.37 The fluxes of nitrogen-containing compounds across the portal vein,

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carotid artery, and hepatic vein were calculated using methods described previously.21,28

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Notably, we distinguished between the fluxes of nitrogen-containing compounds across the

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portal vein and the net portal fluxes of nitrogen-containing compounds. The former is the

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product of the plasma flow rate across the portal vein and the concentration of plasma

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nitrogen-containing compounds in the portal vein. The latter is the product of PVPF and the

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difference in the concentrations of plasma nitrogen-containing compounds between the

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portal vein and carotid artery. The consumption rate of AA in the liver (mg/min) was

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calculated as: AA concentration in hepatic artery (mg/mL) × HAPF (mL/min) + AA

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concentration in portal vein (mg/mL) × PVPF (mL/min) – AA concentration in hepatic vein 10


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(mg/mL) × HVPF (mL/min). It should be noted that the concentrations of AA in the hepatic

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artery and carotid artery are the same, as the composition of arterial blood is essentially the

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same at all sampling sites; the catheter was inserted into the carotid, rather than the hepatic,

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artery for convenience. The production rate of urea in the liver (mg/min) was calculated as:

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Urea concentration in hepatic vein (mg/mL) × HVPF (mL/min) – urea concentration in

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hepatic artery (mg/mL) × HAPF (mL/min) – urea concentration in portal vein (mg/mL) ×

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PVPF (mL/min).

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Statistical analysis. Data, including nitrogen intake; urinary and fecal nitrogen excretion;

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nitrogen retention; concentrations of plasma nitrogen-containing compounds in the portal

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vein, hepatic artery, and hepatic vein; fluxes of nitrogen-containing compounds across the

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corresponding vessels; net portal fluxes of nitrogen-containing compounds; consumption

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rate of AA in the liver; and production rate of urea in the liver, were analyzed with a mixed

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linear model (MIXED procedure) as implemented in SAS (SAS Institute, Cary, NC, USA).

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The model used was:

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Yij = µ + Ti + Aj + eij

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where Yij = dependent variable, µ = overall mean, Ti = treatment (i =1, 2, 3), A = animal (j

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= 1, 2, 3, 4, 5), and eij = residual error. Differences between treatment means were

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determined by Tukey’s multiple comparison test. Results are reported as means ± SEM and

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were considered statistically significant at P < 0.05.

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RESULTS

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As shown in Table 2, with the exception of lysine, methionine, threonine, and tryptophan,

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the daily intakes of all other AA were reduced following the reduction in dietary CP (P
0.05) (Table 3).

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The plasma flows across the portal vein, hepatic artery, and hepatic vein are presented

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in Table 4. The low-protein diets (15% and 13.5% CP) resulted in decreases in PVPF and

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HVPF (P < 0.05). The concentrations of plasma nitrogen-containing compounds in the 12


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portal vein, hepatic artery, and hepatic vein are presented in Table 5. The concentrations of

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plasma aspartate in the portal veins of pigs in the 15% and 13.5% CP groups and those of

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serine in the portal veins of pigs in the 13.5% CP group were significantly lower than

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those in pigs in the 18% CP group (P < 0.05). By contrast, there were no differences in the

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concentrations of plasma AA or NH3 in the hepatic artery among the three groups (P >

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0.05). Compared with the 18% CP diet, the 15% CP diet led to decreases in the

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concentrations of plasma leucine, proline, and aspartate in the hepatic vein. Similarly,

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compared to the 18% CP diet, the 13.5% CP diet led to decreases in the concentrations of

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plasma leucine, phenylalanine, histidine, proline, aspartate, serine, and tyrosine in the

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hepatic vein (P < 0.05).

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The fluxes of plasma nitrogen-containing compounds across the portal vein, hepatic

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artery, and hepatic vein are presented in Table 6. The fluxes of plasma aspartate, serine,

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cystine, tyrosine, and NH3 across the portal veins of pigs in the 15% CP group and the

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fluxes of plasma isoleucine, leucine, phenylalanine, histidine, arginine, proline, aspartate,

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serine, glutamate, glycine, alanine, cystine, tyrosine, EAA, NEAA, total AA (TAA), NH3,

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and urea across the portal veins of pigs in the 13.5% CP group were lower than those in

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pigs fed the control (18% CP) diet (P < 0.05). Moreover, a reduction in dietary CP content

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from 18% to 15% or 13.5% reduced the fluxes of all measured plasma AA and NH3 across

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the hepatic artery (P < 0.05). Across the hepatic vein, the 13.5% CP diet resulted in

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decreases in the fluxes of plasma isoleucine, leucine, phenylalanine, histidine, arginine, 13



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proline, aspartate, serine, cystine, tyrosine, EAA, NEAA, TAA, and urea compared to

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those in the 18% CP group. Similarly, the 15% CP diet resulted in decreases in the fluxes

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of plasma isoleucine, leucine, proline, aspartate, and tyrosine across the hepatic vein

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compared to those in the 18% CP group (P < 0.05). In addition, while not significant, the

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diet with the lowest protein content (13.5% CP) tended to reduce the fluxes of isoleucine

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(P = 0.098), arginine (P = 0.107), and EAA (P = 0.104) across the portal vein and the

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fluxes of threonine (P = 0.063), valine (P = 0.069), methionine (P = 0.061), lysine (P =

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0.066), tryptophan (P = 0.092), glycine (P = 0.057), and alanine (P = 0.091) across the

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hepatic vein.

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The net release of nitrogen-containing compounds into the portal vein are presented in

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Table 7. With the exception of threonine (P = 0.197), methionine (P = 0.634), lysine (P =

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0.551), and tryptophan (P = 0.596), the net portal fluxes of all AA, EAA, NEAA, TAA,

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and NH3 were reduced following reductions in dietary CP (P 0.05).

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DISCUSSION

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In this study, low-protein diets supplemented with four EAA (threonine, lysine, tryptophan,

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and methionine) resulted in reduced intake of all non-supplemented AA. Consistent with

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previous reports,2,6,7,9,14 we observed that feeding pigs a low-protein diet successfully

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reduced nitrogen excretion. However, the reduction in dietary CP content also led to a

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decrease in nitrogen retention, which is closely related to animal growth. This result is

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consistent with previous studies, which reported a negative effect on pig growth

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performance when dietary CP content was reduced by ≥ 3%.11,14,16,17 In this study, in

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comparison with pigs fed a control diet (18% CP), pigs fed a diet with 15% CP exhibited

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reductions in urinary nitrogen excretion, fecal nitrogen excretion, and total nitrogen

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excretion of 14.2%, 19.7%, and 16.2%, respectively, while those fed a diet with 13.5% CP

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exhibited corresponding reductions of 21.5%, 29.3%, and 24.7%, respectively. Thus, the

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decreased proportion of fecal nitrogen was greater than that of urinary nitrogen, the latter of 15



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which typically accounts for over half of the total nitrogen excretion.38,39

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This relatively high urinary excretion can be explained by changes in the release of

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nitrogen-containing precursors by the PDV and in urea production in the liver in response

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to different dietary CP contents. We found that low-protein diets resulted in decreases in the

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urea production rate in the liver, as well as in the net portal fluxes of NH3, glycine, and

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alanine. Notably, NH3, glycine, and alanine were found to be primary nitrogen sources for

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urea in our previous study, with glycine- and alanine-derived urea accounting for 13.5%

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and 15.7% of the total urea produced by the liver;29 this suggests that attempts to reduce

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urinary nitrogen excretion should limit the entry of these compounds into the liver. In the

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current study, the net portal fluxes of glycine, alanine, and NH3 in pigs fed the 15% CP diet

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were reduced by 7.05%, 6.58%, and 8.18%, respectively, and those in pigs fed the 13.5%

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CP diet were reduced by 15.4%, 16.0%, and 16.8%, respectively, compared to values in the

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control group, while the urea production rates in the liver were reduced by 7.27% and

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16.0% in the two groups, respectively. Thus, the reductions in nitrogen-containing

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precursors released by the PDV and urea production in the liver did not exceed the

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reductions in AA intake, which were 15.3% and 23.1% in the 15% and 13.5% CP groups,

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respectively.

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We also found that reductions in dietary CP intake resulted in reductions in the

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concentrations of two plasma AAs in the portal vein and seven plasma AAs in the hepatic

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vein, as well as in 11 plasma AA fluxes across the portal vein, 18 plasma AA fluxes across 16


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the hepatic artery, and 10 plasma AA fluxes across the hepatic vein. These results indicate

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that dietary CP levels influence AA flux more than AA concentration in plasma. Moreover,

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these results can be attributed to the fact that dietary CP primarily influences plasma flux

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across the portal vein and hepatic vein. Additionally, in comparison with the control diet,

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the 15% CP diet resulted in reductions in the net portal fluxes of EAA and NEAA of 6.52%

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and 20.9% respectively, while the 13.5% CP diet resulted in corresponding reductions of

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13.9% and 30.1%, respectively. These results indicate that the reduced proportion of NEAA

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supply from the PDV was much greater than that of EAA supply. This seems to be a direct

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consequence of the experimental design, because some (not all) EAA were provided as

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supplements to the low-protein diets. However, the reductions in the net portal flux of

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NEAA exceeded the reductions in NEAA intake (16.0% and 25.6% in the 15% and 13.5%

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CP groups, respectively). This may be related to fact that NEAA fuel metabolism. NEAA,

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notably glutamine, glutamate, and aspartate, are substantially metabolized in the PDV,24,40

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despite the reduction in the proportion of oxidized NEAA to oxidized TAA under

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protein-restricted but isocaloric feeding conditions.41 In recent years, NEAA have been

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recognized as essential in animals for not only normal growth and maintenance but also the

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synthesis of many bioactive compounds.42,43 There is a rapidly growing body of literature

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that demonstrates the immune benefits of specific NEAA.44–46 NEAA deficiency was

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shown to reduce the average daily body weight gain, feed efficiency, and final body weight

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of growing pigs.16 The results of the present study suggest that low-protein diets reduce the 17



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supply of NEAA to the liver.

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Finally, we also observed that a low-protein diet (13.5% CP) increased EAA

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consumption in the liver. The liver regulates the blood AA composition, which affects the

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supply of AA to peripheral tissues.26–28 When the NEAA supply from the PDV is low, EAA

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are used to synthesize NEAA to balance the composition of AA leaving the liver.47 As

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mentioned above, the reductions in the net portal flux of NEAA in the low-protein groups

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were much greater than the reductions in the net portal flux of EAA. Therefore, the large

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reductions in NEAA may be a primary cause of the increased EAA consumption observed

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in the livers of pigs fed low-protein diets. The increase in EAA consumption in the liver

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induced by NEAA deficiency does not favor optimal AA utilization.

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In conclusion, feeding pigs low-protein diets supplemented with four EAA resulted in

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reductions in nitrogen excretion but also in nitrogen retention. Low-protein diets led to

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decreases in the NEAA supply and increases in EAA consumption in the liver. These

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changes in AA metabolism are not favorable for AA anabolism. The deficiency of NEAA

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may be a major disadvantage of low-protein diets. The results of the present study provide a

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potential explanation for the growth-limiting effects of low-protein diets currently in use.

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Thus, the supplementation of low-protein diets with important NEAA (e.g., glutamate, an

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oxidative substrate in the intestinal mucosa) may be more effective in balancing the profile

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of AA from the intestines, decreasing the EAA consumption in the liver and improving the

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AA use efficiency.25,41,48 18


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ACKNOWLEDGEMENTS

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We gratefully acknowledge the National Science and Technology Major Project of China

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(2017YFD0500504), the National Natural Science Foundation of China (31772610), and

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the National “948” Project from the Ministry of Agriculture of China (2015Z74). We thank

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Zhengya Liu, Yong Fang, Xiaoqiang Xue, and Dandan Zhang for technical support during

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catheter surgery.

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Notes

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All authors read and approved the final manuscript.

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REFERENCES

382

(1) Le Bellego, L.; van Milgen, J.; Noblet, J. Effect of high temperature and low-protein

383

diets on the performance of growing-finishing pigs. J. Anim. Sci. 2002, 80, 691–701.

384

(2) Shriver, J. A.; Carter, S. D.; Sutton, A. L.; Richert, B. T.; Senne, B. W. Effects of adding

385

fiber sources to reduced-crude protein, amino acid-supplemented diets on nitrogen

386

excretion, growth performance, and carcass traits of finishing pigs. J. Anim. Sci. 2003, 81,

387

492–502.

388

(3) Pilcher, C. M.; Arentson, R.; Patience, J. F. The interaction of fiber, supplied by

389

distillers dried grains with solubles, with an antimicrobial and a nutrient partitioning agent

390

on nitrogen balance, water utilization, and energy digestibility in finishing pigs. J. Anim.

391

Sci. 2015, 93: 1124–1132.

392

(4) Kerr, B. J.; Southern, L. L.; Bidner, T. D.; Friesen, K. G.; Easter, R. A. Influence of

393

dietary protein level, amino acid supplementation, and dietary energy levels on

394

growing-finishing pig performance and carcass composition. J. Anim. Sci. 2003, 81,

395

3075–3087.

396

(6) Gallo, L.; Montà, G. D.; Carraro, L.; Cecchinato, A.; Carnier, P.; Schiavon, S. Growth

397

performance of heavy pigs fed restrictively diets with decreasing crude protein and

398

indispensable amino acids content. Livest. Sci. 2014, 161, 130–138.

399

(6) Hernández, F.; Martínez, S.; López, C.; Megías, M. D.; López, M.; Madrid J. Effect of

400

dietary crude protein levels in a commercial range, on the nitrogen balance, ammonia 20


Page 20 of 44

Page 21 of 44


401

emission and pollutant characteristics of slurry in fattening pigs. Animal 2011, 5,

402

1290–1298.

403

(7) Galassi, G.; Colombini, S.; Malagutti, L.; Crovetto, G. M.; Rapetti, L. Effects of high

404

fibre and low protein diets on performance, digestibility, nitrogen excretion and ammonia

405

emission in the heavy pig. Anim. Feed Sci. Tech. 2010, 16, 1140–1148.

406

(8) Li, Y.; Li, F.; Duan, Y.; Guo, Q.; Wang, W.; Wen, C.; Huang, X.; Yin, Y. The protein and

407

energy metabolic response of skeletal muscle to the low-protein diets in growing pigs. J.

408

Agric. Food Chem. 2017, 65, 8544–8551.

409

(9) Zhang, S.; Chu, L.; Qiao, S.; Mao, X.; Zeng, X. Effects of dietary leucine

410

supplementation in low crude protein diets on performance, nitrogen balance, whole-body

411

protein turnover, carcass characteristics and meat quality of finishing pigs. Anim. Sci. J.

412

2016, 87, 911–920.

413

(10) Hong, J. S.; Lee, G. I.; Jin, X. H.; Kim, Y. Y. Effect of dietary energy levels and phase

414

feeding by protein levels on growth performance, blood profiles and carcass characteristics

415

in growing-finishing pigs. J. Anim. Sci. Technol. 2016, 58, 37.

416

(11) Lu, N.; Yi, X.; Qiao, S.; Liu, Q. The application of crystal amino acids in low protein

417

diets of growing pigs. Am. Sci. 2008, 2, 17–25.

418

(12) Otto, E. R.; Yokoyama, M.; Ku, P. K.; Ames, N. K.; Trottier, N. L. Nitrogen balance

419

and ileal amino acid digestibility in growing pigs fed diets reduced in protein concentration.

420

J. Anim. Sci. 2003, 81, 1743–1753. 21



421

(13) Le, P. D.; Aarnink, A. J. A.; Jongbloed, A. W. Odour and ammonia emission from pig

422

manure as affected by dietary crude protein level. Livest. Sci. 2009, 121, 267–274.

423

(14) Shaw, M. I.; Beaulieu, A. D.; Patience, J. F. Effect of diet composition on water

424

consumption in growing pigs. J. Anim. Sci. 2006, 84, 3123–3132.

425

(15) Kerr, B. J.; Easter, R. A. Effect of feeding reduced protein, amino acid-supplemented

426

diets on nitrogen and energy balance in grower pigs. J. Anim. Sci. 1995, 73, 3000–3008.

427

(16) He, L.; Wu, L.; Xu, Z.; Li, T.; Yao, K.; Cui, Z.; Yin, Y.; Wu, G. Low-protein diets affect

428

ileal amino acid digestibility and gene expression of digestive enzymes in growing and

429

finishing pigs. Amino Acids 2016, 48, 21–30.

430

(17) Figueroa, J. L.; Lewis, A. J.; Miller, P. S.; Fischer, R. L.; Gómez, R. S.; Diedrichsen, R.

431

M. Nitrogen metabolism and growth performance of gilts fed standard corn-soybean meal

432

diets or low-crude protein, amino acid-supplemented diets. J. Anim. Sci. 2002, 80,

433

2911–2919.

434

(18) Knowles, T. A.; Southern, L. L.; Bidner, T. D.; Kerr, B. J.; Friesen, K. G. Effect of

435

dietary fiber or fat in low-crude protein, crystalline amino acid-supplemented diets for

436

finishing pigs. J. Anim. Sci. 1998, 76, 2818–2832.

437

(19) Bush, J. A.; Burrin, D. G.; Suryawan, A.; O'Connor, P. M.; Nguyen, H. V.; Reeds, P. J.;

438

Steele, N. C.; Van Goudoever, J. B.; Davis, T. A. Somatotropin-induced protein anabolism

439

in hindquarters and portal-drained viscera of growing pigs. Am. J. Physiol. Endocrinol.

440

Metab. 2003, 284, E302–E312. 22


Page 22 of 44

Page 23 of 44


441

(20) Wilkinson, D. L.; Bertolo, R. F. P.; Brunton, J. A.; Shoveller, A. K.; Pencharz, P. B.;

442

Ball, R. O. Arginine synthesis is regulated by dietary arginine intake in the enterally fed

443

neonatal piglet. Am. J. Physiol. Endocrinol. Metab. 2004, 287, E454–E462.

444

(21) Yin, Y. L.; Huang, R. L.; Li, T. J.; Ruan, Z.; Xie, M. Y.; Deng, Z. Y.; Hou, Y. Q.; Wu, G.

445

Y. Amino acid metabolism in the portal-drained viscera of young pigs: effects of dietary

446

supplementation with chitosan and pea hull. Amino acids 2010, 39, 1581–1587.

447

(22) Rojas-Cano, M.; Fernández-Fígares, I.; Lara, L.; Lachica, M. Influence of betaine and

448

conjugated linoleic acid on portal-drained viscera flux of metabolites in growing Iberian

449

pigs. J. Anim. Sci. 2016, 94, 207–210. (26) Wu, G. Intestinal mucosal amino acid

450

catabolism. J. Nutr. 1998, 128, 1249–1252.

451

(23) Stoll, B.; Henry, J.; Reeds, P. J.; Yu, H.; Jahoor, F.; Burrin, D. G. Catabolism dominates

452

the first-pass intestinal metabolism of dietary essential amino acids in milk protein-fed

453

piglets. J. Nutr. 1998, 128, 606–614.

454

(24) Riedijk, M. A.; de Gast-Bakker, D. A.; Wattimena, J. L.; van Goudoever, J. B.

455

Splanchnic oxidation is the major metabolic fate of dietary glutamate in enterally fed

456

preterm infants. Pediatr. Res. 2007, 62, 468–473.

457

(25) Haussinger D. Glutamine metabolism in the liver: overview and current concepts.

458

Metabolism 1989, 38, 14–17.

459

(26) Stoll, B.; Burrin, D. G.; Henry, J.; Jahoor, F.; Reeds, P. J. 1998. Dietary amino acids are

460

the preferential source of hepatic protein synthesis in piglets. J. Nutr. 128, 1517–1524. 23



461

(27) Spanaki, C.; Plaitakis, A. 2012. The role of glutamate dehydrogenase in mammalian

462

ammonia metabolism. Neurotoxic. Res. 21, 117–127.

463

(28) Li, L.; Zhang, P.; Zheng, P.; Bao, Z.; Wang, Y.; Huang, F. R. Hepatic cumulative net

464

appearance of amino acids and related gene expression response to different protein diets in

465

pigs. Livest. Sci. 2015, 182, 11–21.

466

(29) Yang, J. Study for the metabolic fate of glycine and alanine in the porcine liver[D].

467

Master thesis, Southwest University, Chongqing, China, 2016 (In Chienese).

468

(30) Zhang, H. F.; Zhang, Z. Y. Animal Nutrition Parameters and Feeding Standard. China

469

Agriculture Press: Beijing, China, 1998 (In Chinese).

470

(31) National Research Council (NRC). Nutrient Requirements of Swine. 11th rev. ed.;

471

National Academies Press: Washington, DC, 2012.

472

(32) AOAC. Official Methods of Analysis. 17th rev. ed.; Association of Official Analytical

473

Chemistis: Washington DC, USA, 2000.

474

(33) AOAC. Official Methods of Analysis. 18th rev. ed.; Association of Official Analytical

475

Chemistis: Arlington, USA, 2006.

476

(34) Myers, W. D.; Ludden, P. A; Nayigihugu, V; Hess, B. W. Technical note: A procedure

477

for the preparation and quantitative analysis of samples for titanium dioxide. J. Anim. Sci.

478

2004, 82, 179–183.

479

(35) Pan, L.; Ma, X. K.; Wang, H. L.; Xu, X.; Zeng, Z. K.; Tian, Q. Y.; Zhao, P. F.; Zhang,

480

S.; Yang, Z. Y.; Piao, X. S. Enzymatic feather meal as an alternative animal proteinsource in 24


Page 24 of 44

Page 25 of 44


481

diets for nursery pigs. Anim. Feed Sci. Tech. 2015, 212, 112–121.

482

(36) Calder, A. G.; Garden, K, E.; Anderson, S. E.; Lobley, G. E. Quantitation of blood and

483

plasma amino acids using isotope dilution electron impact gas chromatography/mass

484

spectrometry with U-13C amino acids as internal standards. Rapid Commun. Mass

485

Spectrom. 1999, 13, 2080–2083.

486

(37) Zhu, L. H.; Armentano, L. E.; Bremmer, D. R.; Grummer, R. R.; Bertics, S. J. Plasma

487

concentration of urea, ammonia, glutamine around calving, and the relation of hepatic

488

triglyceride, to plasma ammonia removal and blood acid-base balance. J. Dairy Sci. 2000,

489

83, 734–740.

490

(38) Patráš, P.; Nitrayová, S.; Brestenský, M.; Heger, J. Effect of dietary fiber and crude

491

protein content in feed on nitrogen retention in pigs. J. Anim. Sci. 2012, 90, 158–160.

492

(39) Shirali, M.; Doeschl-Wilson, A.; Knap, P. W.; Duthie, C.; Kanis, E.; van Arendonk, J.

493

A.; Roehe, R. Nitrogen excretion at different stages of growth and its association with

494

production traits in growing pigs. J. Anim. Sci. 2012, 90, 1756–1765.

495

(40) van der Schoor, S. R.; van Goudoever, J. B.; Stoll, B.; Henry, J. F.; Rosenberger, J. R.;

496

Burrin, D. G.; Reeds, P. J. The pattern of intestinal substrate oxidation is altered by protein

497

restriction in pigs. Gastroenterology 2001, 121, 1167–1175.

498

(41) Stoll, B.; Burrin, D. G. Measuring splanchnic amino acid metabolism in vivo using

499

stable isotopic tracers. J. Anim. Sci. 2006, 84, E60–E72.

500

(42) Ban, H.; Shigemitsu, K.; Yamatsuji, T.; Haisa, M.; Nakajo, T.; Takaoka, M.; Nobuhisa, 25



501

T.; Gunduz, M.; Tanaka, N.; Naomoto, Y. Arginine and leucine regulate p70 S6 kinase and

502

4E-BP1 in intestinal epithelial cells. Int. J. Mol. Med. 2004, 13, 537–543.

503

(43) Rhoads, J. M.; Wu, G. Glutamine, arginine, and leucine signaling in the intestine.

504

Amino Acids 2009, 37, 111–122.

505

(44) Meijer, A. J.; Dubbelhuis, P. F. Amino acid signaling and the integration of metabolism.

506

Biochem. Biophys. Res. Commun. 2004, 313, 397–403.

507

(45) Hammami, I.; Chen, J.; Bronte, V.; DeCrescenzo, G.; Jolicoeur, M. L-glutamine is a

508

key parameter in the immunosuppression phenomenon. Biochem. Biophys. Res. Commun.

509

2012, 425, 724–729.

510

(46) Grimble, R. F. The effects of sulfur amino acid intake on immune function in humans.

511

J. Nutr. 2006, 136, 1660S–1665S.

512

(47) Wu, G.; Bazer, F. W.; Dai, Z.; Li, D.; Wang, J.; Wu, Z. Amino acid nutrition in animals:

513

protein synthesis and beyond. Annu. Rev. Anim. Biosci. 2014, 2, 387–417.

514

(48) Reeds, P. J.; Burrinm D, G.; Stollm, B.; Jahoor, F. Intestinal glutamate metabolism. J.

515

Nutr. 2000, 130, 978S–982S.

26


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Page 27 of 44


Table 1. Ingredients and composition of diets differing in CP content, fed to 30~60 kg pigs Diets 18% CP

15% CP

13.5% CP

Corn

61.20

69.22

73.51

Soybean meal

26.40

17.05

12.27

Wheat bran

7.75

6.88

5.02

Soybean oil

1.55

2.36

2.95

Lysine

0.18

0.46

0.58

Methionine

0.05

0.09

0.12

Threonine

0.01

0.14

0.26

Tryptophan

0.00

0.02

0.07

Dicalcium phosphate

0.69

0.78

0.90

Calcium carbonate

0.87

0.89

0.90

Salt

0.30

0.30

0.30

Glucose

0.00

0.80

1.80

Sodium dichloroacetate

0.00

0.01

0.02

1% premix 1

1.00

1.00

1.00

Ingredients (%)



Total

Page 28 of 44

100.00

100.00

100.00

ME (MJ/kg) 2

13.9

13.9

13.9

CP 3

18.0

15.0

13.6

Threonine3

0.73

0.71

0.73

Valine3

0.68

0.54

0.49

Methionine3

0.33

0.33

0.33

Isoleucine3

0.71

0.57

0.52

Leucine3

1.35

1.08

0.97

Phenylalanine3

0.79

0.65

0.58

Lysine3

1.10

1.09

1.09

Histidine3

0.44

0.37

0.32

Arginine3

1.01

0.8

0.74

Tryptophan3

0.20

0.19

0.2

Proline3

0.73

0.59

0.55

Aspartate3

1.76

1.43

1.31

Serine3

0.74

0.59

0.54

Glutamate3

2.95

2.41

2.16

Glycine3

0.58

0.48

0.43

Composition（% unless indicated otherwise）


Page 29 of 44


Alanine3

0.79

0.65

0.59

Cystine3

0.24

0.19

0.18

Tyrosine3

0.37

0.3

0.27

Ca3

0.60

0.63

0.61

P3

0.51

0.48

0.48

1

Composition per kg of premix: 119 g MgSO4·H2O, 2.5 g FeSO4·7H2O, 0.8 g CuSO4·5H2O,

3 g MnSO4·H2O, 5 g ZnSO4·H2O, 10 mg Na2SeO3, 40 mg KI, 30 mg CoCl2·6H2O, 11000 IU vitamin A, 1100 IU vitamin D3, 22 IU vitamin E, 4 mg menadione as dimethylpyrimidinol bisulfate, 0.03 mg vitamin B12, 28 mg d-pantothenic acid, 33 mg niacin and 0.08% choline chloride. 2

Calculated values according to the data of Zhang and Zhang.32

3

Determined values.

Abbreviation: ME, metabolizable energy.



Page 30 of 44

Table 2. The AA intakes of pigs in the experiment of nitrogen balance (g/d) Treatments SEM

P

18% CP

15% CP

13.5% CP

Threonine

12.0

12.1

12.4

0.20

0.828

Valine

12.6a

10.8b

9.80c

0.18

Low-Protein Diets Decrease Porcine Nitrogen Excretion but with

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