Scanning Electron Microscopy of the Chicken Crop—the Avian Rumen?1,2 R. C. BAYER, C. B . CHAWAN AND F . H . BIRD
Department of Animal and Veterinary Services, University of Maine, Orono, Maine 04473 (Received for publication July 22, 1974)
POULTRY SCIENCE 54: 703-707,
INTRODUCTION
T
HE significance of the esophageal pouch in the chicken, the crop, in the digestive process is not well understood and it has had little importance attributed to it besides its storage function. It has the same general structure as the esophagus, in that it is lined with stratified squamous epithelium which in some instances was observed to slough (Calhoun, 1954). Bolton (1965) demonstrated that as sugar disappeared from the crop, the amount of lactic acid, acetic acid and ethanol increased. Pritchard (1972) showed that sucrose is slowly hydrolyzed in the crop and that fructose is produced equivalent to the amount of sucrose hydrolyzed. Also that glucose and maltose are produced in the crop by hydrolysis of starch by salivary amylase. The objective of the present study was to examine the surface structure of the crop and assess the potential role of the crop in the digestive process. MATERIALS AND METHODS Crop tissue samples were prepared for study of the mucosal surface topography by
1975
scanning electron microscopy according to the method of Bayer et al. (1974). Samples were obtained by sacrificing four 14 week old, floor-raised, male and three 50 week old female Red x Rock cross chickens by an overdose of anesthetic. Samples were immersed in fixative or fixative was injected intoligated crops. The prepared samples were examined with a Cambridge Stereoscan S-4 Scanning Electron Microscope (SEM). RESULTS The crop surface appeared to be divided into two major regions. The first of these regions was located in an area in proximity to the esophagus. This area had a slightly convoluted surface (Figure 1) but its most outstanding characteristic was the dense population of rod shaped bacteria (Figure 2). Some food particles were observed to be adhering to the crop surface (Figure 3). Some of the bacilli were attached to feed particles (Figure 4). The other major surface area of the crop was around the apex of the diverticulum. This area was considerably flatter than the esophageal area and numerous epithelial cells were sloughing (Figure 5). There were fewer bacterial cells in this area.
1. Funded by Hatch Project 289 from the Maine Agricultural Experiment Station. 2. With technical assistance of Sandra Beaulieu.
DISCUSSION The crop of the chicken appeared to closely 703
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on April 6, 2015
ABSTRACT The mucosal surface of the chicken crop was examined with the scanning electron microscope. The proximal region in relation to the esophagus differed markedly from the distal region. The region nearest the esophagus showed a slightly folded surface with a very dense surface bacterial population while the region located in the apical region of the diverticulum was smoother with numerous sloughing cells and a sparse bacterial population. A potential for significant microbiological fermentation and digestion of feed in the crop is indicated.
704
R. C. BAYER, C. B. CHAWAN AND F. H. BIRD
FIG. 2. Scanning electron micrograph of esophageal region of crop mucosa at high magnification. Note numerous rod shaped bacteria. Epithelial cell nuclei are pointed out with arrows.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on April 6, 2015
FIG. 1. Scanning electron micrograph of the esophageal region of the crop mucosa. Numerous recesses are seen.
705
CHICKEN CROP MICROSCOPY
«
A
•*
A.
*
J
Fio. 3. Scanning electron micrograph showing feed particles and debris in contact with crop mucosa. Arrows point to probable starch granules.
FIG. 4. Scanning electron micrograph of feed particles at high magnification. Arrows point to bacteria on the surface of a feed particle.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on April 6, 2015
43J4
706
R. C. BAYER, C. B. CHAWAN AND F. H. BIRD
resemble the surface of the bovine rumen as examined in this laboratory (Musgrave et at., 1973). The rumen had a greater surface area per epithelial cell because of the presence of micro-papillae. The presence of the large bacterial population observed, similar in morphology to those populations seen in the rumen, present a potential for fermentation of feed while it is in the crop. Further evidence of the digestive potential of the crop bacteria was the adherence of some bacteria to crop feed particles. The round feed particles seen in Figures 4 and 5 were probably endosperm granules. The granules seen in the crop were very similar in size and shape to endosperm granules examined with SEM by Davis and Harbers (1974). Bolton (1965) and Pritchard (1972) presented evidence for bacterial and enzymatic digestion of starches to sugars, alcohol and organic acids. According to Bolton (1965) bacteriological fermentation occurred when
the crop contents were incubated anaerobically and lactic acid and acetic acid were found. The predominant micro-organism in the crop was Lactobacillus (Bolton, 1965). There was also evidence of bacteriological and enzymatic degradation of starches to sugars in the crop according to Pritchard (1972). REFERENCES Bayer, R. C, F. H. Bird, S. D. Musgrave and C. B. Chawan, 1974. A simple method of preparation of gastrointestinal tract tissues for scanning electron microscopy. J. Ani. Sci. 38: 354-356. Bolton, W., 1965. Digestion in the crop of the fowl. British Poultry Sci. 6: 97-102. Calhoun, M. L., 1954. Microscopic Anatomy of the Digestive System of the Chicken. The Iowa State College Press. Iowa. Davis, A. B., and L. H. Harber, 1974. Hydrolysis of sorghum grain starch by rumen micro-organisms and purified porcine a amylase as observed by scanning electron microscopy. J. Ani. Sci. 38: 900-907. Musgrave, S. D., R. C. Bayer, T. A. Bryan and C.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on April 6, 2015
FIG. 5. Scanning electron micrograph of crop mucosa in apical region. Arrows denote sloughing cells.
CHICKEN CROP MICROSCOPY
B. Chawan, 1973. Bovine G.I. tract mucosa studied with SEM. J. Dairy Sci. 56: 1381.
707
Pritchard, P. J., 1972. Digestion of sugars in the crop. Comp. Biochem. Physiol. 43A: 195-205.
Some Effects on Layers of Sodium Sulfate and Magnesium Sulfate in Their Drinking Water! A. W. ADAMS, F. E. CUNNINGHAM AND L. L. MUNGER2
(Received for publication July 23, 1974)
ABSTRACT Potential for increasing contamination of water supplies with such materials as dissolved inorganic solids suggests more precise water quality standards for poultry. Commercial strain S.C.W.L. hens were supplied water containing sodium sulfate (Na 2 S0 4 ) or magnesium sulfate (MgSOJ (250, 1,000, 4,000, or 16,000 p.p.m.) on a total sulfate basis in Exp. 1 and on a total salt basis in Exp. 2. All data are expressed as percentages deviated from pre-treatment performance. Four thousand p.p.m. of total sulfate as Na 2 S0 4 or MgS0 4 significantly depressed feed consumption and hen-day production. Magnesium sulfate (4,000 p.p.m.) had a more depressing effect than Na 2 S0 4 (4,000 p.p.m.) on hen-day production (-80.4 vs. -24.4%). At that level, Na 2 S0 4 significantly increased water consumption and fecal moisture content, while MgS0 4 significantly decreased water consumption. All hens on 16,000 p.p.m. of either salt died during the experiment. No effect on egg quality was observed before the hens died. On a total salt basis (Exp. 2) 16,000 p.p.m. of either Na 2 S0 4 or MgS04 significantly depressed hen-day production, body weight, and feed consumption, but increased water consumption. Hens receiving 16,000 p.p.m. Na 2 S0 4 increased water consumption more than those receiving 16,000 p.p.m. MgS04 (146.7 and 24.6%). No significant differences between treatments were observed for mortality (Exp. 2). Mortality data suggest that lethal levels of Na 2 S0 4 and MgS04 are between 16,000 and 20,032 or 23,680 p.p.m. total salt, respectively. POULTRY SCIENCE 54: 707-714, 1975
INTRODUCTION
P
OTENTIAL for increasing contamination
in drinking water for human health is listed as 250 p.p.m. (Anonymous, 1962); but re-
of water supplies with such materials as
searchers have reported that higher levels do
dissolved inorganic solids suggests that more
not adversely affect poultry. Keinholz (1968)
precise water quality standards are needed
reported 18,000 p.p.m. MgS0 4 , when given
for poultry. Standards for human health fre-
to turkeys from 0-4 wk. of age, increased
quently are applied to poultry because data
their water consumption and fecal moisture
are limited on effects of various inorganic
content and reduced rate of gain; less salt
materials on poultry. For example, the per-
showed no adverse effects.
missible level of either sulfate or chloride
With laying hens, 10,000 p.p.m. NaCl or MgS0 4 reduced egg production; however, 12,000 p.p.m. of N a S 0 4 was required to show
1. Contribution 895, Dairy and Poultry Science Department and 7, Diagnostic Laboratory, Veterinary Medicine, Kansas Agricultural Experiment Station, Kansas State University, Manhattan, Kansas 66506. 2. Present Address: Wilson and Co., Box 289, Springdale, Arkansas 72764.
that effect (Krista et al., 1961). Mulheam (1957) and Olson et al. (1959) suggest that approximately 4,000 p.p.m. total dissolved solids is the upper safe limit for poultry.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on April 6, 2015
Departments of Dairy and Poultry Sciences and Diagnostic Laboratory, Kansas State University, Manhattan, Kansas 66506
Department of Animal and Veterinary Services, University of Maine, Orono, Maine 04473 (Received for publication July 22, 1974)
POULTRY SCIENCE 54: 703-707,
INTRODUCTION
T
HE significance of the esophageal pouch in the chicken, the crop, in the digestive process is not well understood and it has had little importance attributed to it besides its storage function. It has the same general structure as the esophagus, in that it is lined with stratified squamous epithelium which in some instances was observed to slough (Calhoun, 1954). Bolton (1965) demonstrated that as sugar disappeared from the crop, the amount of lactic acid, acetic acid and ethanol increased. Pritchard (1972) showed that sucrose is slowly hydrolyzed in the crop and that fructose is produced equivalent to the amount of sucrose hydrolyzed. Also that glucose and maltose are produced in the crop by hydrolysis of starch by salivary amylase. The objective of the present study was to examine the surface structure of the crop and assess the potential role of the crop in the digestive process. MATERIALS AND METHODS Crop tissue samples were prepared for study of the mucosal surface topography by
1975
scanning electron microscopy according to the method of Bayer et al. (1974). Samples were obtained by sacrificing four 14 week old, floor-raised, male and three 50 week old female Red x Rock cross chickens by an overdose of anesthetic. Samples were immersed in fixative or fixative was injected intoligated crops. The prepared samples were examined with a Cambridge Stereoscan S-4 Scanning Electron Microscope (SEM). RESULTS The crop surface appeared to be divided into two major regions. The first of these regions was located in an area in proximity to the esophagus. This area had a slightly convoluted surface (Figure 1) but its most outstanding characteristic was the dense population of rod shaped bacteria (Figure 2). Some food particles were observed to be adhering to the crop surface (Figure 3). Some of the bacilli were attached to feed particles (Figure 4). The other major surface area of the crop was around the apex of the diverticulum. This area was considerably flatter than the esophageal area and numerous epithelial cells were sloughing (Figure 5). There were fewer bacterial cells in this area.
1. Funded by Hatch Project 289 from the Maine Agricultural Experiment Station. 2. With technical assistance of Sandra Beaulieu.
DISCUSSION The crop of the chicken appeared to closely 703
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on April 6, 2015
ABSTRACT The mucosal surface of the chicken crop was examined with the scanning electron microscope. The proximal region in relation to the esophagus differed markedly from the distal region. The region nearest the esophagus showed a slightly folded surface with a very dense surface bacterial population while the region located in the apical region of the diverticulum was smoother with numerous sloughing cells and a sparse bacterial population. A potential for significant microbiological fermentation and digestion of feed in the crop is indicated.
704
R. C. BAYER, C. B. CHAWAN AND F. H. BIRD
FIG. 2. Scanning electron micrograph of esophageal region of crop mucosa at high magnification. Note numerous rod shaped bacteria. Epithelial cell nuclei are pointed out with arrows.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on April 6, 2015
FIG. 1. Scanning electron micrograph of the esophageal region of the crop mucosa. Numerous recesses are seen.
705
CHICKEN CROP MICROSCOPY
«
A
•*
A.
*
J
Fio. 3. Scanning electron micrograph showing feed particles and debris in contact with crop mucosa. Arrows point to probable starch granules.
FIG. 4. Scanning electron micrograph of feed particles at high magnification. Arrows point to bacteria on the surface of a feed particle.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on April 6, 2015
43J4
706
R. C. BAYER, C. B. CHAWAN AND F. H. BIRD
resemble the surface of the bovine rumen as examined in this laboratory (Musgrave et at., 1973). The rumen had a greater surface area per epithelial cell because of the presence of micro-papillae. The presence of the large bacterial population observed, similar in morphology to those populations seen in the rumen, present a potential for fermentation of feed while it is in the crop. Further evidence of the digestive potential of the crop bacteria was the adherence of some bacteria to crop feed particles. The round feed particles seen in Figures 4 and 5 were probably endosperm granules. The granules seen in the crop were very similar in size and shape to endosperm granules examined with SEM by Davis and Harbers (1974). Bolton (1965) and Pritchard (1972) presented evidence for bacterial and enzymatic digestion of starches to sugars, alcohol and organic acids. According to Bolton (1965) bacteriological fermentation occurred when
the crop contents were incubated anaerobically and lactic acid and acetic acid were found. The predominant micro-organism in the crop was Lactobacillus (Bolton, 1965). There was also evidence of bacteriological and enzymatic degradation of starches to sugars in the crop according to Pritchard (1972). REFERENCES Bayer, R. C, F. H. Bird, S. D. Musgrave and C. B. Chawan, 1974. A simple method of preparation of gastrointestinal tract tissues for scanning electron microscopy. J. Ani. Sci. 38: 354-356. Bolton, W., 1965. Digestion in the crop of the fowl. British Poultry Sci. 6: 97-102. Calhoun, M. L., 1954. Microscopic Anatomy of the Digestive System of the Chicken. The Iowa State College Press. Iowa. Davis, A. B., and L. H. Harber, 1974. Hydrolysis of sorghum grain starch by rumen micro-organisms and purified porcine a amylase as observed by scanning electron microscopy. J. Ani. Sci. 38: 900-907. Musgrave, S. D., R. C. Bayer, T. A. Bryan and C.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on April 6, 2015
FIG. 5. Scanning electron micrograph of crop mucosa in apical region. Arrows denote sloughing cells.
CHICKEN CROP MICROSCOPY
B. Chawan, 1973. Bovine G.I. tract mucosa studied with SEM. J. Dairy Sci. 56: 1381.
707
Pritchard, P. J., 1972. Digestion of sugars in the crop. Comp. Biochem. Physiol. 43A: 195-205.
Some Effects on Layers of Sodium Sulfate and Magnesium Sulfate in Their Drinking Water! A. W. ADAMS, F. E. CUNNINGHAM AND L. L. MUNGER2
(Received for publication July 23, 1974)
ABSTRACT Potential for increasing contamination of water supplies with such materials as dissolved inorganic solids suggests more precise water quality standards for poultry. Commercial strain S.C.W.L. hens were supplied water containing sodium sulfate (Na 2 S0 4 ) or magnesium sulfate (MgSOJ (250, 1,000, 4,000, or 16,000 p.p.m.) on a total sulfate basis in Exp. 1 and on a total salt basis in Exp. 2. All data are expressed as percentages deviated from pre-treatment performance. Four thousand p.p.m. of total sulfate as Na 2 S0 4 or MgS0 4 significantly depressed feed consumption and hen-day production. Magnesium sulfate (4,000 p.p.m.) had a more depressing effect than Na 2 S0 4 (4,000 p.p.m.) on hen-day production (-80.4 vs. -24.4%). At that level, Na 2 S0 4 significantly increased water consumption and fecal moisture content, while MgS0 4 significantly decreased water consumption. All hens on 16,000 p.p.m. of either salt died during the experiment. No effect on egg quality was observed before the hens died. On a total salt basis (Exp. 2) 16,000 p.p.m. of either Na 2 S0 4 or MgS04 significantly depressed hen-day production, body weight, and feed consumption, but increased water consumption. Hens receiving 16,000 p.p.m. Na 2 S0 4 increased water consumption more than those receiving 16,000 p.p.m. MgS04 (146.7 and 24.6%). No significant differences between treatments were observed for mortality (Exp. 2). Mortality data suggest that lethal levels of Na 2 S0 4 and MgS04 are between 16,000 and 20,032 or 23,680 p.p.m. total salt, respectively. POULTRY SCIENCE 54: 707-714, 1975
INTRODUCTION
P
OTENTIAL for increasing contamination
in drinking water for human health is listed as 250 p.p.m. (Anonymous, 1962); but re-
of water supplies with such materials as
searchers have reported that higher levels do
dissolved inorganic solids suggests that more
not adversely affect poultry. Keinholz (1968)
precise water quality standards are needed
reported 18,000 p.p.m. MgS0 4 , when given
for poultry. Standards for human health fre-
to turkeys from 0-4 wk. of age, increased
quently are applied to poultry because data
their water consumption and fecal moisture
are limited on effects of various inorganic
content and reduced rate of gain; less salt
materials on poultry. For example, the per-
showed no adverse effects.
missible level of either sulfate or chloride
With laying hens, 10,000 p.p.m. NaCl or MgS0 4 reduced egg production; however, 12,000 p.p.m. of N a S 0 4 was required to show
1. Contribution 895, Dairy and Poultry Science Department and 7, Diagnostic Laboratory, Veterinary Medicine, Kansas Agricultural Experiment Station, Kansas State University, Manhattan, Kansas 66506. 2. Present Address: Wilson and Co., Box 289, Springdale, Arkansas 72764.
that effect (Krista et al., 1961). Mulheam (1957) and Olson et al. (1959) suggest that approximately 4,000 p.p.m. total dissolved solids is the upper safe limit for poultry.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on April 6, 2015
Departments of Dairy and Poultry Sciences and Diagnostic Laboratory, Kansas State University, Manhattan, Kansas 66506
