Kidney Damage in Laying Hens (Urolithiasis) Robert F. Wideman, Jr., Ph.D. Professor of Poultry Science Center of Excellence for Poultry Science University of Arkansas Fayetteville, AR 72701-1201
Chickens have 2 Kidneys Each Kidney has 1 Ureter Each Kidney has 3 Divisions • cranial • medial • caudal 1 Renal Artery per Division Symmetrical in Shape and Weight Renal Reserve Capacity: Only 2 divisions are needed for sustained egg production!
Nickel, Schummer, Seiferle, Siller, and Wight. 1977. Anatomy of the Domestic Birds. Springer-Verlag, New York. Figure 90, page 96.
Pullet Kidneys
Hen Kidneys
Urolithiasis Pathology (uroliths = kidney stones)
Earliest Damage: Focal Mineralization
Early Damage: Focal Tissue Degeneration
Unilateral Urolith Formation
Unilateral Urolith + Kidney Degeneration
Unilateral Urolith + Kidney Degeneration
Unilateral Kidney Degeneration
Bilateral Urolith Formation Leads to Visceral Gout
Bilateral Kidney Failure Causes Visceral Gout
Commercial SCWL Hens 2% to 50% Mortality
Wideman et al., 1983. Kidney Function of pullets and laying hens during outbreaks of urolithiasis. Poultry Sci. 62: 1954-1970.
Response to Unilateral or Bilateral Surgical Ureteral Obstruction
Wideman and Gregg, 1988. Model for evaluating avian renal hemodynamics and glomerular filtration rate autoregulation. Am. J. Physiol. 254: R925-R932.
Normal Flock 11
Urolithiasis Flock
10
Left Kidney Weight (g)
9 8
Normal Kidneys are Symmetrical (Heavy Kidney / Light Kidney) < 1.10
7 6
Urolithiasis = Kidney Asymmetry (Heavy Kidney / Light Kidney) > 1.10
5 4
Urolithiasis Kidney Function depends on kidney weight
3
• Glomerular Filtration Rate • Renal Plasma Flow Rate • Urine Flow rate
2 1
1
2
3
4
5
6
7
8
9
10
11
Right Kidney Weight (g) Wideman et al., 1983. Kidney Function of pullets and laying hens during outbreaks of urolithiasis. Poultry Sci. 62: 1954-1970.
Early Symptoms of Urolithiasis • • • • • • •
Acquired degenerative kidney disease Affects pullets and laying hens Focal mineralization of the kidneys Uroliths block the ureter Atrophy “upstream” of the uroliths Unobstructed kidney tissue undergoes compensatory hypertrophy Kidney asymmetry is characteristic of damage leading to urolithiasis!
Urolithiasis Mortality • • • • • •
Affected birds exhibit no symptoms until 24 h prior to death Affected hens continue to lay eggs Flock mortalities total 2% to 50% Mortality diagnosed as “visceral gout” Many survivors have damaged kidneys Poor prospects for molting affected flocks
Suspected Causes • • • • •
High dietary calcium (Ca) Low dietary available phosphorus (P) Nephropathogenic IBV Water deprivation Genetic susceptibility
Dietary Calcium and Phosphorus
HCLP Feed: High Calcium > 3.5% (HC); Low available Phosphorus < 0.4% (LP) Bone
HCLP Feed
Ca
P plasma
Ca+P Mineral
1,25 (OH)2D3
+
P
P plasma
Ca
Ca plasma
Parathyroid Hormone
P
Intestine
Improved Bone Mineral
Ca plasma
Kidneys Decreased Tubular Ca Reabsorption
Urine Shell Gland
Improved Eggshell Quality
Shell
Ca
Ca Increased risk of Urolithiasis
Shane, Young, and Krook. 1969. Renal and parathyroid changes produced by high calcium intake in growing pullets. Avian Dis. 13:558-567. Wideman. 1987. Renal regulation of avian calcium and phosphorus metabolism. 1987. J. Nutrition 117:808-815.
All Chicks NCNP Starter 1% Ca, 0.6% aP All Pullets (7 weeks old)
NCNP Feed 1% Ca, 0.6% aP
HCNP Feed 3.5% Ca, 0.6% aP
NCLP Feed 1% Ca, 0.4% aP
HCLP Feed 3.5% Ca, 0.4% aP
Pullets (18 weeks old) Layer Feed 3.5% Ca
Pullets (18 weeks old) Layer Feed 3.5% Ca
Pullets (18 weeks old) Layer Feed 3.5% Ca
Pullets (18 weeks old) Layer Feed 3.5% Ca
Hens (51 weeks old)
Hens (51 weeks old)
Hens (51 weeks old)
Hens (51 weeks old)
Wideman, R. F., J. A. Closser, W. B. Roush, and B. S. Cowen. Urolithiasis in pullets and laying hens: Role of dietary calcium and phosphorus. Poultry Sci. 64: 2300-2309, 1985.
Table 1. Incidence of urolithiasis for pullets or hens raised from 7 weeks of age on diets containing normal or high calcium (NC = 1% Ca; HC = 3.5% Ca), and normal or low available phosphorus (NP = 0.6% aP; LP = 0.4% aP). Pullets were necropsied at 18 wks, and hens at 51 wks of age.
NCNP
(%)
HCNP
(%)
Pullets
0/95
0a
1/88
1a
Hens
0/111
0a
13/108
12b
NCLP
(%)
HCLP
(%)
0/92
0a
13/93
14b
2/107
2a
15/111
14b
From: Wideman, R. F., J. A. Closser, W. B. Roush, and B. S. Cowen. Urolithiasis in pullets and laying hens: Role of dietary calcium and phosphorus. Poultry Sci. 64: 2300-2309, 1985.
Table 2. Kidney function in 18-week-old pullets fed diets containing normal or high calcium (NC = 1% Ca; HC = 3.5% Ca), and normal or low available phosphorus (NP = 0.6% aP; LP = 0.4% aP).
NCNP
HCNP
NCLP
HCLP
1.42ab
1.34b
1.56a
1.25b
Fractional Ca Excretion
0.04b
0.10b
0.08b
0.98a
Fractional Pi Excretion
0.70a
0.35b
0.37b
0.07c
Urine pH
5.52b
5.40b
5.46b
5.85a
Glomerular Filtration Rate1 mL/KgBW/min
From: Wideman, R. F., J. A. Closser, W. B. Roush, and B. S. Cowen. Urolithiasis in pullets and laying hens: Role of dietary calcium and phosphorus. Poultry Sci. 64: 2300-2309, 1985.
Impact of Dietary Ca and aP • • • • • • •
High Ca pullet diets trigger urolithiasis in hens Low aP amplifies the impact of high Ca HCLP diets flood the urine with calcium HCLP diets reduce the acidity of the urine Damage can remain “hidden” in pullets until hens begin laying (HCNP Treatment) Role of “pre-layer” rations? Role of phytase (phosphorus availability)?
Wideman, R. F., J. A. Closser, W. B. Roush, and B. S. Cowen. 1985. Urolithiasis in pullets and laying hens: Role of dietary calcium and phosphorus. Poultry Sci. 64: 2300-2309. Glahn, R. P., Wideman, R. F., and Cowen, B. S. 1988. Effect of Gray strain infectious bronchitis virus and high dietary calcium on renal function of SCWL pullets at 6, 10 and 18 weeks of age. Poultry Sci. 67: 1250-1263. Rao, S. K., Roland, D. A., and Orban, J. I. 1991. Influence of dietary cholecalciferol, calcium, and phosphorus on urinary calcium in commercial laying hens. Poultry Sci. 70:1921-1927.
Infectious Bronchitis Virus
Blaxland, J. D., Borland, E. D., Siller, W. G., and Martindale, L. 1980. An investigation of urolithiasis in two flocks of laying fowls. Avian Pathol. 9:5-19. Mallinson, E. T., Rothenbacher, H., Wideman, R. F., Snyder, D. B., Russek, E., Zuckerman, A. I., and Davidson, J. P. 1984. Epizootiology, pathology, and microbiology of an outbreak of urolithiasis in chickens. Avian Dis. 28: 25-43. Cowen, B. S., Wideman, R. F., Rothenbacher, H., and Braune, M. O. 1987. An outbreak of urolithiasis on a large commercial egg farm. Avian Dis. 31: 392-397.
Table 3. Incidence of urolithiasis and gross kidney damage for pullets raised from 6 wks of age on diets containing normal or high calcium (NC = 1% Ca; HC = 3.5% Ca), and that either remained unexposed to IBV (N) or were exposed to nephropathogenic Gray strain IBV at 14 weeks of age (IBV). Survivors were necropsied at 21 weeks of age.
NC
(%)
Urolithiasis
0/103
0c
Gross Damage
0/104
0c
NC+IBV (%)
HC
(%)
HC+IBV (%)
0/66
0c
12/96
12.5b 22/84
26.2a
0/66
0c
19/96
19.8b 28/84
33.3a
Glahn, R.P., Wideman, R.F., and Cowen, B.S. 1989. Order of exposure to high dietary calcium and Gray strain infectious bronchitis virus (IBV) alters renal function and the incidence of urolithiasis. Poultry Sci. 68: 1193-1204.
Impact of IBV • • • •
Urolithiasis outbreaks have been associated with changes in IBV vaccination Nephropathogenic IBV strains have been isolated from affected hens IBV does not seem to trigger urolithiasis in the absence of HC (layer-type) diets When HC diets are fed, IBV greatly amplifies the Ca-induced incidence of urolithiasis
Niznik, Wideman, Cowen, and Kissell. 1985. Induction of urolithiasis in Single Comb White leghorn pullets: effect on glomerular number. Poultry Sci. 64:1430-1437. Cowen, B. S., Wideman, R. F., Braune, M. O. and Owen, R. L. 1987. An infectious bronchitis virus isolated from chickens experiencing a urolithiasis outbreak. I. In vivo characterization studies. Avian Dis. 31: 878-883. Wideman, R. F. and Cowen, B. S. 1987. Effect of dietary acidification on kidney damage induced in immature chickens by excess calcium and infectious bronchitis virus. Poultry Sci. 66: 626-633. Glahn, R. P., Wideman, R. F., and Cowen, B. S. 1988. Effect of Gray strain infectious bronchitis virus and high dietary calcium on renal function of SCWL pullets at 6, 10 and 18 weeks of age. Poultry Sci. 67: 1250-1263.
Water Deprivation Prolonged dehydration was suspected of triggering urolithiasis in commercial flocks Experimental Design: Pullets: No water 5 d per wk, 12 through 17 wk of age Hens: No water 3 of every 5 d, 37 through 42 wk of age
Julian, R. 1982. Water deprivation as a cause of renal disease in chickens. Avian Pathol. 11:615-617. Closser, J. A., 1986. MS Thesis The Pennsylvania State University: The Effects of Diet and Infectious Bronchitis on Urolithiasis in Poultry. M.S. in Poultry Science, The Pennsylvania State University.
Table 4. Incidence of urolithiasis for pullets or hens raised from 7 to 18 weeks of age on diets containing normal or high calcium (NC = 1% Ca; HC = 3.25% Ca), and normal or low available phosphorus (NP = 0.6% aP; LP = 0.4% aP), and that were dehydrated or received water ad libitum during pullet growout or during the laying phase. Pullets were necropsied at 18 wk, and hens at 51 wk. NCNP
(%)
HCNP
(%)
NCLP
(%)
HCLP
(%)
Hydrated Pullets
0/49
0b
1/48
2.1ab
0/49
0b
6/48
12.5a
Dehydrated Pullets
0/46
0b
0/40
0b
0/43
0b
7/45
15.5a
Hydrated Hens
0/68
0b
8/70
11.4a
1/71
1.4b
12/73
16.4a
Dehydrated Hens
0/43
0b
5/38
13.2a
1/36
2.8ab
3/38
7.9a
From: Closser, J. A. 1986. The Effects of Diet and Infectious Bronchitis on Urolithiasis in Poultry. MS Thesis, The Pennsylvania State University.
Impact of Water Deprivation? •
•
•
Depriving pullets of water 5 days per week for 5 consecutive weeks failed to amplify the incidence of Ca-induced urolithiasis Depriving hens of water for 3 out of every 5 days for 5 consecutive weeks failed to amplify the incidence of urolithiasis Trials involving more subtle water deprivation, to avoid reducing feed intake, have not been conducted
Similar Urolith Composition Worldwide • • •
Unique mineral: Calcium-Sodium-Urate Similar mechanisms involved worldwide? Urinary acidification predicted to prevent new uroliths from forming, and to dissolve existing uroliths
Oldroyd, N. G. and Wideman, R. F. 1986. Characterization and composition of uroliths from domestic fowl. Poultry Sci. 65: 1090-1094.
Urine pH and Dietary Cation:Anion Balance (alkalinizing) (acidifying) (Na+ + K+ + Ca++ + Mg++) - (Cl- + PO4= + SO4=)
High Ca Diet
NaHCO3 added for Eggshell Quality
NH4Cl added as acidifier
Low aP Diet (low phytase) NH4SO4 added as acidifier; also excess Met, MHA, HMB
Oldroyd, N. G. and Wideman, R. F. 1986. Characterization and composition of uroliths from domestic fowl. Poultry Sci. 65: 1090-1094. Manning, R. A., and Blaney, B. J. 1986. Identification of uroliths by infrared spectroscopy. Austr. Vet. J. 63:393-395. Wideman, R. F. and Cowen, B. S. 1987. Effect of dietary acidification on kidney damage induced in immature chickens by excess calcium and infectious bronchitis virus. Poultry Sci. 66: 626-633. Wideman, R.F., Roush, W.B., Satnick, J.L., Glahn, R.P., and Oldroyd, N.O. 1989. Methionine hydroxy analog (free acid) reduces avian kidney damage and urolithiasis initiated by excess dietary calcium. J. Nutrition 119: 818-828.
AVIAN UROLITHIASIS (GOUT) TECHNICAL BULLETIN A PUBLICATION OF HY-LINE INTERNATIONAL WEBSITE: WWW.HYLINE.COM
Adding ammonium chloride, ammonium sulfate, DL-methionine, and methionine hydroxy analogue (Alimet) all successfully acidify the urine. For flocks experiencing gout mortality, ammonium sulfate or ammonium chloride are recommended as shown in the following table: %
Lbs/ton
Kg/ton
1st week
0.25
5
2.5
2nd week
0.50
10
5.0
3rd week
0.75
15
7.5
4th week +
1.00
20
10.0
• Acidifying the urine keeps kidney stones dissolved and preserves functional renal mass of affected birds. • Wet droppings may be a side effect of ammonium chloride usage, but not with ammonium sulfate. • After 4-6 weeks of the maximum treatment level, if the desired results have been obtained, gradual reductions may be made. • Some level of treatment (around 0.5%) will likely be needed for the flock’s life. • Both DL-methionine and Alimet can be used at up to 6 Kg/ton (12 Lbs./ton) of the diet.
Tubular Fluid
Interstitial Fluid Uric Acid secretion
Na Urate (Filtered)
Active Uric Acid transport
Na Urate from the Liver
Cellular Muco-Protein secretion
Urate-
Tubular Epithelial Cells
Na+ / K+ / Ca++ Layered Spherule
K Urate
Blood
Na+/H+ antiport
Na+
Na+
Na+ H+
H+
Intracellular Acid hydronium ions, H3O+
ATP
3Na+ 2K+
NH3
ADP + Pi
UrateH+ /
K+ /
Na+
NH3
Ca++
ATP Layered Spherule
UrateH+ / NH4+ / Ca++
H+ K+
Cl- / HCO3+ Exchanger
HCO3-
H+ ATPase Proton Pump
HCO3-
ClHCO3-
ADP + Pi
Carbonic Anhydrase
H+
OH↑↓
CO2 (metabolic)
Cl Channel -
Cl-
HCO3Net NaHCO3 addition to the blood
H20 Net Titratable Acid Excretion: Net H+ loss in the urine
©2000 1999
Impact of Urinary Acidification • • • • •
Acidifiers effectively prevent uroliths from forming and dissolve pre-existing uroliths 0.5% Ammonium Sulfate is the treatment of choice worldwide for dissolving uroliths 0.5% Ammonium Sulfate has no measurable negative biological impact Once initiated, acidification must continue otherwise mortality will resume Excessive acidification kills hens with severe kidney damage
Wideman, R. F. and Cowen, B. S. 1987. Effect of dietary acidification on kidney damage induced in immature chickens by excess calcium and infectious bronchitis virus. Poultry Sci. 66: 626-633. Lent, A., and Wideman, R.F. 1993. Susceptibility of two commercial Single Comb White Leghorn strains to calcium-induced urolithiasis: efficacy of dietary supplementation with D-L methionine and ammonium sulfate. British Poultry Sci. 34:577-587. Lent, A.J., and Wideman, R. F. 1994. Hypercalciuric response to dietary supplementation with dl-methionine and ammonium sulfate. Poultry Sci. 73:63-74.
Strain Differences in Urolithiasis Susceptibility • • •
SCWL strains differ in their microscopic kidney anatomy SCWL strains differ in their ability to concentrate their urine and reduce manure moisture Field reports suggest SCWL strains differ in their susceptibility to urolithiasis
R M
R
M M
R
Glomeruli x 103 per Kidney
The Susceptible SCWL Strain: • has fewer Reptilian-Type nephrons • has more Mammalian-Type nephrons • forms a more concentrated urine Resistant Susceptible
200 180
*
120
* 80
40
* .42
Glomerular Size Categories (mm circumference) Unflat, J. G., Kissell, R. E., Wideman, R. F., and Muir, F. V. 1985. A comparison of two techniques for determining glomerular size distributions in domestic fowl. Poultry Sci. 64: 1210-1215. Wideman, R. F. Kidney Anatomy and Physiology. 1988. In: CRC Critical Reviews in Poultry Biology. Ed. R. R. Dietert. CRC Press, Volume 1 (2):133-176. Roush, W. B., and Spotts, C. B. 1988. Strain differences in the number and size of glomeruli in domestic fowl. British Poultry Sci. 29:113-117.
Table 5. Incidence of urolithiasis and gross kidney damage for SCWL pullets from strains A and B raised from 5 to 18 weeks of age on diets containing normal or high calcium (NC = 1% Ca; HC = 3.5% Ca; both containing 0.4% aP), with or without supplemental ammonium sulfate (0.5% AS). Pullets were necropsied at 18 weeks of age. NC
NC+AS
HC
HC+AS
Strain A Urolithiasis (%)
0b
0b
38a
0b
Strain B Urolithiasis (%)
0b
0b
0b
0b
Strain A Kidney Damage (%)
0b
0b
63a
0b
Strain B Kidney Damage (%)
0b
0b
50a
13ab
From: Lent, A., and Wideman, R.F. 1993. Susceptibility of two commercial Single Comb White Leghorn strains to calcium-induced urolithiasis: efficacy of dietary supplementation with D-L methionine and ammonium sulfate. British Poultry Sci. 34:577-587.
Impact of Strain Differences • •
•
Strain-related differences in urolithiasis susceptibility have been confirmed Strains whose kidneys excrete a concentrated urine at low flow rates (low manure moisture) are more susceptible to urolithiasis Management strategies must accommodate the biological characteristics of each SCWL strain
UROLITHIASIS: Nutrition x Disease x Genetic Interactions
QUESTIONS & DISCUSSION