Slide 1: Histidine – a limiting amino acid for dairy cows
Histidine – a limiting amino acid for dairy cows Alexander N. Hristov Distinguished Professor, Department of Animal Science The Pennsylvania State University BALCHEM’s Real Science Lecture Series, March 4th, 2025
Slide 2: Talk outline
Talk outline • Feeding reduced-protein diets to dairy cows • Why Histidine? • Early research • Research at Penn State • Conclusions
Slide 3: Why feeding low-protein diets?
Why feeding low-protein diets? • Reduced feed cost • Striving for efficiency • Reduced N emissions (nitrates, NH3, N2O) • Protein overfeeding and reproduction
Slide 4: It all started with ammonia…
It all started with ammonia… • Eutrophication of water bodies • Ground water Ammonia emissions in the US quality Industrial • Air pollution processes Transportation Livestock 51% Fertilizer application Half from ruminants
Slide 5: Decreasing urinary N/urea excretion decreases manure ammonia emissions
Lee et al., 2010 Decreasing urinary N/urea excretion decreases manure ammonia emissions 250 High-CP diet 1200 P < 0.01 Lines, P < 0.001 Low-CP diet Cumulative ammonia emission, mg 1000 200 800 47% 150 PP<<0.01 0.01 600 400 100 200 50 0 High CP, 16% CP Low CP, 14% CP 0 0 20 40 60 80 100 120 140 Urina
Slide 6: Dietary CP influences soil ammonia emissions as well
Lee et al., 2016 Dietary CP influences soil ammonia emissions as well 7.0 vs 2.6 g/m2/h P < 0.01
Slide 7: Sources of nitrous oxide emissions in the United States & effect of diet CP
USEPA, 2024 Sources of nitrous oxide emissions in the United States & effect of diet CP
Slide 8: More recently, enteric methane became a target: low-protein & high-starch diets
Räisänen et al., 2022 More recently, enteric methane became a target: low-protein & high-starch diets Starch replaced RUP; 16.7 vs 15.4% CP; 110% vs 96% of MP requirements; 23.2 vs 25.0% starch 450 16 P = 0.08 P = 0.001 15 400 14 350 13 300 12 250 11 200 10 Methane, g/d Methane, g/kg DMI AMP2.1His A
Slide 9: Low-protein, high-starch diets?
Cueva et al., 2024 Low-protein, high-starch diets? Milk fat % decreased, but milk protein and ECM yields and ECM feed efficiency increased with increasing dietary starch concentration 45 13.0 CH4, g/kg ECM = 13.1559 - 0.0717 × Starch, % of DM P = 0.02, linear; P = 0.06, quadratic 12.5 R2 = 0.96; P <
Slide 10: Severe MP deficiency likely to decrease DMI, milk yield & components
Penn State data Severe MP deficiency, however, are likely to decrease DMI, milk yield & components 45 Control-MY 40 LowCP-MY 35 Control-DMI 16% 14% LowCP-DMI 30 CP CP Kg/d 25 20 3 kg less milk 15 P = 0.04 P = 0.26 10 5 0
Slide 11: Or cows will lose BW
Giallongo et al., 2014 Or cows will lose BW 400 P = 0.06 to 0.10 350 300 250 HCP LCP 200 LCPO 150 LCPOM 100 LCPOMH 50 0 BW change BW change, g/d
Slide 12: What is Histidine?
What is Histidine? • Unique among EAA with an imidazole side chain • Similar to Met, a Group 1 AA (extracted by the liver with post-liver supply approx. equal to mammary uptake and output in milk) • Which would suggest that requirements for His should be similar to those for Met • However, variabili
Slide 13: Net flux of Met and His
Net flux of Met and His Lapierre et al., 2008
Slide 14: Histidine research over the years
Räisänen et al., 2023 Histidine research over the years
Slide 15: Science, 1966
‘4 PennState . . J College of Agricultural Sciences Milk Production of Cows on Protein-Free Feed Studies of the use of urea and ammonium salts as the sole nitrogen source open new important perspectives. Artturi I, Virtanen Science, 1966 Fig. 3. Test cow Metta after being on test feed 370 days from
Slide 16: A. I. Virtanen; Science, 1966
A. I. Virtanen; Science, 1966 Cow on normal feed Cow on synthetic feed
Slide 17: Histidine concentration in feeds
Evonik AMINODat Histidine concentration in feeds 6 NASEM: His, % of CP 8 5 6 2.58 2.68 4 4 2 3 0 Blood meal SSBM Canola meal Feather meal 2 1 0 His, % of feed
Slide 18: His concentration in common forages and protein feeds
His concentration in common forages and protein feeds
Slide 19: Can His be limiting on CS-based diets?
Can His be limiting on CS-based diets? His supply ÷ output in grass- vs. corn silage-based diets 80 1.2 Vanhatalo et al., 1999 Lee et al., 2012 70 1 60 0.8 50 1.07 vs. 1.05 40 0.6 30 42 vs. 70 45 vs. 73 0.4 20 0.2 10 0 0 His supply, g/d His in milk TP, g/d His ratio (His in milk protein÷His supply w
Slide 20: Histidine work at Penn State
MBS" J. Dairy Sci. 99:6702-6713 @ http://dx.doi.org/10.3168/jds.2015-10673 SS © American Dairy Science Association”, 2016 Effects of slow-release urea and rumen-protected methionine and histidine on mammalian target of rapamycin (mTOR) signaling and ubiquitin Lactational perf ffects of f tal proteas
Slide 21: Histidine work at Penn State
Histidine work at Penn State • Observed a consistent apparent drop in plasma His with long-term feeding of low-CP diets • Hypothesis: on low-CP diets, microbial protein is becoming an increasingly important source of AA for the cow – However, compared with Met, microbial protein is a poorer source o
Slide 22: Examples of the effect of dietary CP/MP on plasma His
60 CP = 15.7 vs. 13.6% 50 Examples of the effect 40 P < 0.01 30 of dietary CP/MP on 20 plasma His 10 0 0.6 Plasma His, uM CP = 15.6 vs. 14% MPA diet MPD diet 0.5 P < 0.01 45 0.4 CP = 15.7 vs. 13.6% 40 0.3 35 30 P < 0.01 0.2 25 0.1 20 15 0 10 Plasma His, mg/100 mL 5 No change in Met concentrations MP
Slide 23: Endogenous sources of His
Endogenous sources of His Giallongo et al., 2017: ➢ Blood hemoglobin = 380 g mHis ➢ Muscle carnosine & anserine = 270 g mHis ➢ These could supply mHis for about 7 wks (at approx. – 6 g mHis/d deficiency) Hemoglobin Carnosine Anserine
Slide 24: Body reserves can hide temporary His deficiencies
Hristov et al., 2019 (data from Lee et al., 2012, 2015) Body reserves can hide temporary His deficiencies P = 0.89 P < 0.01
Slide 25: His and blood hemoglobin
Giallongo et al., 2015 His and blood hemoglobin His supplementation 9.4 9.2 a Blood hemoglobin, g/dL a 9 AMP DMP b 8.8 DMPM DMPL b 8.6 DMPH b 8.4 8.2
Slide 26: Met and His in milk protein vs. bacteria
Met and His in milk protein vs. bacteria 10% higher His than Penn State trials Met in milk TP NRC, 2001 3 6 Milk EAA, % Milk CP, % Bacterial EAA, % 2.5 Bacterial CP, % 5 About 18% lower His than Met 2 About 27% lower 4 His than Met 1.5 3 1 2 0.5 1 0 0 Met His Met His
Slide 27: NASEM (2021) AA composition of microbial protein
NASEM (2021) AA composition of microbial protein 16% lower His than Met Only 4% difference
Slide 28: Microbial protein contribution to MP supply increases with decreasing dietary MP
INRA data from Hristov et al., 2019 The relative contribution of microbial protein to the total MP supply increases with decreasing dietary MP
Slide 29: NASEM 2021 simulations
NASEM 2021 simulations Mature, 700 kg BW Holstein cow, 100 DIM, 55 kg milk/d, 3.30% fat, 2.80% TP, 28 kg/d DMI Diet CP, % Proportion of Total mHis, g/d mHis efficiency N excretions, microbial MP (target is 0.75) g/d 15.1 0.58 56 1.04 402 17.2 0.53 67 0.87 488 18.4 0.51 73 0.80 539 0.7 0.6 0.5 0.4 0.
Slide 30: Dietary His, Met and Lys balance
20 15 10 5 0 Dietary His balance, g/d Dietary Met balance, g/d Dietary Lys balance, g/d -5 -10 His-adequate diet His-deficient diet
Slide 31: After 9 wks of feeding the His-deficient diet
100 90 After 9 wks of feeding the His- 80 deficient diet: 70 60 50 P < 0.01 40 30 P < 0.01 20 10 0 Blood His, uM Carnosine, uM His-adequate diet His-deficient diet
Slide 32: DMI, ECM and milk protein on His-adequate vs deficient diet
40 Covariate-adjusted P = 0.02 27.1 vs. 25.4 kg/d 35 P < 0.01 30 25 20 15 10 P = 0.88 5 0 DMI, kg/d ECM, kg/d Milk TP, % His-adequate diet His-deficient diet
Slide 33: RPHis supplementation at the end of the study
RPHis supplementation at the end of the study: + 1.4 kg/d; P < 0.01
Slide 34: Blood hemoglobin, His, and carnosine as affected by His deficiency
Giallongo et al., 2017 Blood hemoglobin, His, and carnosine as affected by His deficiency
Slide 35: Lactational performance optimized at dHis supply of 74 g/d
Lactational performance was optimized at dHis supply of 74 g/d (or 3.0% of MP) No effect on MTP in the MPA diet trial 80 1.12 Linear increase in MY and FE, no effect on DMI 70 1.1 P < 0.01, linear 60 1.08 50 1.06 40 1.04 30 1.02 20 1 10 0.98 0 0.96 dHis supply, g/d Milk TP, kg/d dHis1.8 dHis2.2 dHis
Slide 36: Blood His, carnosine and efficiency across dHis levels
45 1.4 P < 0.001, linear 40 1.2 P < 0.001, linear 35 1 30 25 0.8 20 0.6 15 P < 0.001, linear 0.4 10 0.2 5 0 0 Blood His, uM Blood carnosine, uM EffHis dHis1.8 dHis2.2 dHis2.6 dHis3.0 dHis1.8 dHis2.2 dHis2.6 dHis3.0
Slide 37: Dose-response studies with RPHis: ECM yield effect
Räisänen et al., 2021; 2022 Dose-response studies with RPHis: ECM yield effect with MP-adequate and -deficient diet MP-adequate diet MP-deficient diet 45 45 P = 0.008, quadratic P = 0.004, linear 40 40 35 35 30 30 25 25 20 20 ECM, kg/d ECM, kg/d dHis1.8 dHis2.4 dHis2.8 dHis3.3 dHis1.8 dHis2.4 dHis2.
Slide 38: Lactational performance effects of supplemental histidine: A meta-analysis
Nyy, J. Dairy Sci. 106 § https://doi.org/10.3168/jds.2022-22966 wo: © 2023, The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. ~ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Table 1. Cha
Slide 39: Lactational performance effects of supplemental histidine: A meta-analysis
‘8 PennState ‘Sie: “ys . . J. Dairy Sci. 106:6216-6231 College of Agricultural Sciences }§ https:/idoi.org/10.3168/jds.2022-22966 is © 2023, The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY lice
Slide 40: Dry matter intake and milk yield across adjusted digestible His supply
Dry matter intake and milk yield across adjusted digestible His (adHis) supply
Slide 41: Responses to RPHis supplementation depend on MP supply
Räisänen et al., 2022 Responses to RPHis supplementation depend on MP supply All studies (RPHis and infusion) RPHis studies only 1.15 1.15 MY response, kg/d = 1.5075 - 0.4881*MP supply/MP requirements MY response, kg/d = 1.4540 - 0.4417 x MP supply/MP requirements Adj R2 = 0.51, P < 0.001 Adj R2 = 0
Slide 42: Adj. dHis supply to NEL ratio
Adj. dHis supply adHis supply to NEL ratio (g dHis/Mcal NEL) <1.6, His limiting >1.6, NEL limiting
Slide 43: Be aware of incorrect bioavailability data for RPAA!
Räisänen et al., 2020 Be aware of incorrect bioavailability data for RPAA!
Slide 44: Take-home message
Take-home message • Careful reduction in dietary protein intake will increase milk nitrogen efficiency in dairy cows and will decrease urinary nitrogen losses, nitrate leaching and ammonia and nitrous oxide emissions from dairy manure • Earlier studies with grass silage-based diets and more recently
Slide 45: SID His to Lys ratios fed to growing pigs
SID His to Lys ratios of 26%, 32%, 38%, 43%, and 49% fed to growing pigs……. It was concluded that SID His to Lys ratio between 35% and 41% in diets fed to nursery pigs at 7 to 11 kg enhanced intestinal health and maximized concentrations of His- containing proteins, indicating that His containing pr
Slide 46: QUESTIONS?
QUESTIONS?