View Full Table | Close Full ViewTable 1.

Ingredient composition and nutrient content of experimental diets used in Exp. 2 (as-fed basis)

 
Item HCP1 LCP2
Ingredient composition, % (as-fed basis)
    Corn 64.47 67.39
    Soybean meal, dehulled, 48% CP 23.00 11.73
    Choice white grease 3.33 4.09
    Soy hulls 0 6.50
    Sugar food products3 5.00 5.00
    l-Lys HCl 0 0.33
    l-Ile 0 0.14
    dl-Met 0.03 0.14
    l-Thr 0.09 0.25
    l-Trp 0.01 0.07
    l-Val 0.16 0.36
    Vitamin premix4 0.25 0.25
    Mineral premix5 0.125 0.125
    Sow pack6 0.25 0.25
    Se 2007 0.068 0.068
    Sodium chloride 0.50 0.50
    Limestone 1.17 1.11
    Monocalcium phosphate 1.35 1.50
    Total 100.00 100.00
Calculated nutrient content8
    NE, kcal/kg 2,600 2,600
    CP, % 16.58 12.89
    SID9 Lys, % 0.74 0.74
    SID Ile, % 0.59 0.53
    SID Met, % 0.26 0.26
    SID Met + Cys, % 0.50 0.50
    SID Thr, % 0.59 0.59
    SID Trp, % 0.18 0.18
    SID Val, % 0.81 0.81
    SID Arg, % 0.95 0.63
    SID His, % 0.39 0.28
    SID Leu, % 1.27 0.97
    SID Phe, % 0.7 0.49
    SID Phe + Tyr, % 1.15 0.82
    STTD10 P, % 0.44 0.44
    Total Ca, % 0.88 0.89
    Fermentable fiber, % 10.25 10.00
    SID Lys/NE, g/Mcal 2.83 2.85
Analyzed nutrient content,11 %
    CP 17.62 14.63
    Lys 0.91 (0.86) 0.93 (0.84)
    Ile 0.73 (0.67) 0.68 (0.60)
    Met 0.29 (0.30) 0.28 (0.35)
    Met + Cys 0.55 (0.58) 0.50 (0.57)
    Thr 0.68 (0.70) 0.66 (0.68)
    Trp 0.22 (0.20) 0.22 (0.19)
    Val 0.93 (0.92) 0.98 (0.91)
    Arg 1.08 (1.03) 0.84 (0.69)
    His 0.45 (0.45) 0.36 (0.33)
    Leu 1.58 (1.45) 1.27 (1.12)
    Phe 0.86 (0.80) 0.68 (0.58)
    Phe + Tyr 1.44 (1.34) 1.17 (0.97)
1HCP = high CP (17.6% CP; as-fed basis; analyzed contents).
2LCP = low CP (14.6% CP).
3Sugar food product (International Ingredient Corporation, St. Louis, MO) to increase diet palatability; supplied, per kg, 2,842 kcal NE, 0.05% fermentable fiber, and 1.00% CP.
4Provided the following amounts of vitamins per kilogram of diet: 3,000 IU vitamin A, 300 IU vitamin D3, 20 IU vitamin E, 1 mg menadione (vitamin K), 20 μg vitamin B12, 4 mg riboflavin, 10 mg d-pantothenic acid, and 15 mg niacin.
5Provided the following amounts of trace minerals per kilogram of diet: 640 mg Fe as FeCO3, 260 mg Zn as ZnO, 36 mg Mn as MnO2, 20 mg Cu as CuCl2, and 0.58 mg I as ethylenediamine dihydriodide.
6Provided the following amounts of vitamins per kilogram of diet: 0.10 mg biotin, 250 mg choline as choline chloride, 0.75 mg folic acid, 2.3 mg vitamin B6 as pyridoxine HCl, 10 IU vitamin E as dl-tocopherol acetate, 90 μg Cr as chromium picolinate, and 23 mg carnitine as l-carnitine.
7Provided 0.5 mg of selenium per kg of diet as Na2Se.
8Based on nutrient content in feed ingredients according to the NRC (2012).
9SID = standardized ileal digestible (NRC, 2012).
10STTD = standardized total tract digestible (NRC, 2012).
11Calculated AA contents are shown in parentheses.



View Full Table | Close Full ViewTable 2.

Assay information (TaqMan Gene Expression Assays) for candidate and reference genes

 
Gene Protein Assay ID1 Custom assay
SLC6A14 ATB0,+ [Ss]03376400_u1
SLC7A9 b0,+AT [Ss]03386787_u1
SLC7A1 CAT-1 [Ss]03379090_u1
SLC7A2 CAT-2b [Ss]03389657_m1
SLC7A7 Y+LAT1 [Ss]03389674_g1
SLC7A6 Y+LAT2 CX064558.12
SLC3A1 rBAT [Ss]03818894_s1
SLC3A2 4F2hc [Ss]03377481_u1
VAPB Vesicle-associated membrane protein-associated protein B/C [Ss]03390804_m1
RSP23 Ribosomal protein 23 [Ss]03392259_g1
MRPL39 Mitochondrial ribosomal protein L39 Exon 23
1Assay identification number (ID) for TaqMan Gene Expression Assays (Applied Biosystems, Life Technologies Inc., Grand Island, NY).
2Accession number corresponding to the cDNA sequence tag deposited in the National Center for Biotechnology Information (Bethesda, MD) database used to construct a custom TaqMan assay.
3The human equivalent (NM_017446.3) was blasted against the pig genome, and a region of high alignment (exon 2) was used to construct a custom TaqMan assay.



View Full Table | Close Full ViewTable 3.

Apparent dietary AA utilization efficiency for milk protein production in sows fed high-CP (16.0%) or reduced-CP diets between d 3 and 7 of lactation (early lactation) and between d 14 and 18 of lactation (peak lactation) in Exp. 1

 
Diet1
P-value
Item HCP MHCP MLCP LCP NRC, 20122 SEM3 Linear Quadratic HCP vs. MHCP MHCP vs. MLCP MLCP vs. LCP
No. of sows 9 10 9 10
Early lactation (d 3–7)
    Arg 35.4 36.8 40.2 39.5 8.1 0.669 0.895 0.903 0.767 0.948
    His 58.4 65.7 68.6 73.6 8.6 0.212 0.896 0.552 0.807 0.682
    Ile 48.9 53.0 51.3 50.6 5.2 0.884 0.645 0.579 0.819 0.923
    Leu 46.4 53.9 53.7 59.6 4.8 0.077 0.877 0.283 0.981 0.389
    Lys 67.7 71.0 64.3 62.6 7.1 0.490 0.724 0.742 0.506 0.865
    Met 55.7 60.1 48.4 44.2 6.3 0.114 0.503 0.626 0.201 0.644
    Met + Cys 59.2 66.0 58.9 58.4 5.8 0.712 0.530 0.411 0.391 0.949
    Phe 42.0 48.2 49.6 53.1 4.9 0.126 0.787 0.379 0.848 0.614
    Phe + Tyr 55.3 60.4 61.2 60.4 7.4 0.630 0.695 0.629 0.943 0.944
    Thr 58.6 64.0 56.7 54.1 5.4 0.398 0.469 0.489 0.350 0.738
    Trp 49.9 54.3 48.7 51.8 3.5 0.995 0.850 0.377 0.264 0.536
    Val 44.5 46.6 42.6 39.4 4.6 0.352 0.995 0.748 0.541 0.623
    N 55.3 60.4 61.2 60.4 7.4 0.630 0.695 0.629 0.943 0.944
Peak lactation (d 14–18)
    Arg 31.7 41.0 43.8 53.6 81.6 2.8 <0.0001 0.919 0.021 0.470 0.015
    His 51.8 64.8 67.8 81.5 72.2 3.0 <0.0001 0.919 0.008 0.513 0.006
    Ile 43.1 50.6 51.0 54.3 69.8 2.3 0.002 0.356 0.022 0.909 0.281
    Leu 41.0 49.9 50.8 59.5 72.3 2.2 <0.0001 0.959 0.006 0.765 0.007
    Lys 59.9 68.4 65.4 67.6 67.0 3.0 0.123 0.274 0.042 0.453 0.580
    Met 50.0 58.9 48.8 47.0 67.5 2.3 0.063 0.028 0.010 0.003 0.622
    Met + Cys 52.6 61.6 57.1 57.9 66.2 2.4 0.284 0.091 0.011 0.185 0.810
    Phe 37.0 45.8 48.5 56.9 73.3 2.3 <0.0001 0.930 0.009 0.398 0.012
    Phe + Tyr 48.9 59.6 60.3 68.2 70.5 2.9 <0.0001 0.608 0.012 0.866 0.060
    Thr 52.6 60.0 57.4 59.3 76.4 2.4 0.103 0.248 0.032 0.428 0.559
    Trp4 44.2 48.8 46.6 52.3 67.4 2.0 0.017 0.758 0.108 0.426 0.045
    Val 39.3 45.0 44.5 45.0 58.3 2.0 0.061 0.566 0.041 0.855 0.875
    N 48.9 59.6 60.3 68.2 75.9 2.9 <0.0001 0.608 0.012 0.866 0.060
1HCP = high CP (16.0% CP; as-fed basis; analyzed contents); MHCP = medium-high CP (15.7% CP); MLCP = medium-low CP (14.3% CP); LCP = low CP (14.6% CP).
2Biological maximum AA utilization efficiency for milk protein production according to the NRC (2012).
3Standard error of the mean based on repeated measures analysis (largest value across treatments).
4Tryptophan utilization efficiency tended (P = 0.077) to be less in peak lactation than in early lactation.



View Full Table | Close Full ViewTable 4.

Serum concentration of essential, nonessential and selected AA metabolites for sows fed high-CP (16.0%) or reduced-CP diets in Exp. 11

 
Diet2
P-value
Item HCP MHCP MLCP LCP SEM3 Linear Quadratic
No. of sows 6 6 6 6
EAA,4 μmol/L
    Arg 212 198 213 196 14 0.542 0.892
    His 92 109 107 99 7 0.431 0.047
    Ile 96 94 92 94 5 0.682 0.719
    Leu 197 199 206 186 10 0.573 0.261
    Lys 137 119 123 153 17 0.455 0.107
    Met 46 53 56 57 4 0.026 0.407
    Phe 79 76 75 71 5 0.211 0.896
    Thr 175 203 215 250 10 <0.0001 0.722
    Trp 124 127 128 119 11 0.491 0.200
    Val 318 318 386 411 24 0.001 0.523
    Total EAA 1,489 1,494 1,605 1,642 88 0.092 0.818
NEAA,5 μmol/L
    Ala 575 556 617 679 32 0.017 0.221
    Asn 45 48 48 44 5 0.806 0.389
    Asp 31 30 32 33 5 0.390 0.499
    Cys 21 17 31 27 3 0.032 0.937
    Gln 565 550 605 562 38 0.786 0.706
    Glu 233 204 223 269 31 0.155 0.059
    Gly 894 1,006 1,091 1,053 58 0.042 0.211
    Pro 287 287 306 288 17 0.767 0.603
    Ser 134 129 132 123 10 0.329 0.809
    Tyr 96 105 94 69 7 0.006 0.021
    Total NEAA 2,847 2,919 3,176 3,145 116 0.038 0.665
Metabolite, μmol/L
    3-Methyl-histine 38 37 35 35 5 0.568 0.839
1Blood was sampled 15 h after the evening meal.
2HCP = high CP (16.0% CP; as-fed basis; analyzed contents); MHCP = medium-high CP (15.7% CP); MLCP = medium-low CP (14.3% CP); LCP = low CP (14.6% CP).
3Standard error of the mean based on repeated measures analysis (largest value across treatments).
4EAA = essential AA.
5NEAA = nonessential AA.



View Full Table | Close Full ViewTable 5.

Overall 21-d lactation performance for sows fed high- or low-CP diets in Exp. 2

 
Item HCP1 LCP2 SEM3 P-value4
No. of sows 12 11
Sow initial BW,5 kg 241 261 5 0.005
Sow ADFI, kg/d, as-fed basis 5.14 5.10 0.17 0.828
Litter size at weaning 10.1 9.4 0.3 0.052
Litter growth rate,6 kg/d 1.86 2.18 0.19 0.139
Piglet ADG,6 g/d 186 221 21 0.130
Sow BW change,6 kg −8.7 −9.1 3.4 0.935
1HCP = high CP (17.6% CP; as-fed basis; analyzed contents).
2LCP = low CP (14.6% CP).
3Standard error of the mean based on repeated measures analysis (largest value across treatments).
4Main effect of diet.
5Postfarrowing weight, d 1.
6Over the 21-d lactation period.