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Effect of Dietary Fructose on Broiler Chick Performance1
Effect of Dietary Fructose on Broiler Chick Performance R. D. MILES,2 D. R. CAMPBELL,3 J. A. YATES,3 and C. E. WHITE 34 Departments of Poultry Science and Animal Science, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida 32611 (Received for publication April 4, 1986)
1987 Poultry Science 66:1197-1201 INTRODUCTION
Carbohydrates make up the major energy component of poultry diets. The carbohydrates vary in form from complex molecules such as starch and cellulose to the more simple di- and monosaccharides. Several studies have documented the use of sucrose in poultry diets but very little attention has been given to the use of fructose. Waldroup (1981) and Miles (1983) reviewed the literature regarding molasses and sugar incorporation into poultry diets. Fructose is considered to be the sweetest of all natural sugars and together with glucose is a component of the disaccharide sucrose. Fructose exists naturally in the free form or may be found in polymerized forms in a variety of fruits and vegetables. Not until recently has fructose become available in large quantities from the commercial hydrolysis and enzymatic inversion of corn starch. This development in technology has increased interest in the commercial use of fructose as a dietary carbohydrate.
"Florida Agricultural Experiment Station Journal Series Number 7205. department of Poultry Science. department of Animal Science. 4 Address correspondence to: Agricultural Research and Education Center, Live Oak, Florida 32060.
The present study was carried out to investigate the effects of feeding fructose from highfructose (HFCS) to broiler-type chicks and to determine if feeding fructose would result in an increase in kidney and liver size and elevated plasma uric acid. These three effects have been reported previously in the literature when fructose was fed to other species. MATERIALS AND METHODS
Two experiments were conducted using Cobb feather-sexed chicks. In each experiment chicks were sexed at one day of age and four males and four females were randomly assigned to each replicate in thermostatically controlled, electrically heated Petersime battery brooders with raised wire floors. Chicks were maintained on a 24-h constant-light schedule. Each experiment was conducted for 21 days. All experimental diets and tap water were offered ad libitum throughout the experimental period. In Experiment 1, 384 chicks were weighed and randomly assigned to four treatment groups with 12 replicates of 8 chicks each per treatment. The corn-soybean meal-based experimental diets (Table 1) were formulated to provide the nutrient requirements of growing chicks according to the National Research Council (1977). High-fructose corn syrup furnished dietary fructose and was substituted for corn at the levels
1197
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ABSTRACT The effect of feeding various levels of dietary fructose, furnished by high fructose corn syrup (HFCS), to broiler-type chicks housed in Petersime batteries was studied in two experiments. In experiment 1, HFCS was added to a corn-soybean meal basal diet at levels of 0, 5, 10, and 15%. In Experiment 2, HFCS was added to the diet at levels of 0, 2, 4, 6, and 15%. In both experiments diets were isocaloric and isonitrogenous. In Experiment 1, chicks fed HFCS consumed more feed (P*.05) and grew more rapidly (P=£.05) than chicks fed the control diet. No differences in the feed to gain ratio were observed among treatments. Feeding HFCS resulted in non-significantly higher liver weight and percent liver lipid. Values for kidney weights and plasma uric acid were higher (P=s.05) in chicks fed 15% HFCS. In Experiment 2, adding 4, 6, and 15% HFCS resulted in more rapid growth (Ps.05). No significant differences were observed in feed intake and kidney weights. Chicks fed the 15% HFCS diet had heavier (Ps.05) livers. (Key words: fructose, broilers performance, liver weight, plasma uric acid)
1198
MILES ET AL. TABLE 1. Composition of experimental diets (Experiment 1) Treatment number
Dietary ingredients
1
1
2
55.40 37.25
49.10 38.35 5.00 3.70
3
4
42.85 39.50 10.00 3.80
36.60 40.65 15.00 3.90
- (%)
Calculated analyses4 Crude protein, % Metabolizable energy, kcal/kg Ca, % P, % 1
As-fed basis.
2
High Fructose Corn Syrup.
3.50 .15
.15
.15
.15
1.60 1.20
1.60 1.20
1.60 1.20
1.60 1.20
.40 .50
.40 .50
.40 .50
.40 .50
100.00
100.00
100.00
100.00
23.00 3,070
23.00 3,070
23.00 3,070
23.00 3,070
.92 .44
.92 .44
.92 .44
.92 .44
3 Supplied the following activities per kilogram of diet: vitamin A, 6,600 IU; vitamin D 3 , 2,200 ICU; menadione dimethylpyrimidinol bisulfite, 2.2 mg; riboflavin, 4.4 mg; pantothenic acid, 13.2 mg; niacin, 39.6 mg; choline chloride, 499.4 mg; vitamin B 1 2 , .022 mg; ethoxyquin, .0125%; manganese, 60 mg; iron, 50 mg; copper, 6 mg; iodine, 1.1 mg; and zinc, 35 mg. 4
National Research Council, 1977.
of 0, 5, 10, and 15%. Each diet was formulated to be isocaloric and isonitrogenous. The HFCS contained 80% sugars and 20% moisture (90% fructose on a dry matter basis). Since no metabolizable energy value for HFCS could be found for poultry the value for corn (NRC, 1977) was used. At the termination of the experiment, chicks were weighed individually and feed consumption was determined on a per pen basis. Fourteen male chicks from each treatment were selected randomly. Blood was collected by anterior cardiac puncture and plasma was collected for analysis of uric acid. The liver and both kidneys from each chick were also removed, blotted, and weighed. Livers were frozen until lipid analysis. In addition, eight males with similar body weights from each treatment group were selected, killed, and scalded. The feathers and entire digestive tract were removed and the carcasses were frozen for moisture and lipid analysis. A 3 to 4-g sample of minced homogenized carcass was dried for moisture determination and the lipid content of dried sample
was then determined by Soxhlet extraction with petroleum ether. In Experiment 2, 240 chicks were weighed and randomly assigned to five treatment groups with six replicates of eight chicks each per treatment. The levels of HFCS fed were 0, 2, 4, 6, and 15%, respectively. These levels were selected to confirm the results in Experiment 1 and to determine if dietary levels of HFCS below 5% would result in increased growth and feed intake. The basal diet used in Experiment 2 was identical in composition to the basal diet in Experiment 1. All diets were again formulated to be isocaloric and isonitrogenous. At the termination of the experiment (21 days) 16 male chicks were randomly selected from each treatment group. Chicks were weighed, killed, and their liver and kidneys removed and weighed. Data collected in both experiments were analyzed by analysis of variance; significant difference among means were determined by Duncan's multiple range test (SAS Institute Inc., 1982).
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Corn, ground yellow Soybean meal, dehulled HFCS2 Corn oil Dl-methionine Dicalcium phosphate (22% Ca, 18.5% P) Limestone, ground Salt, iodized Micro ingredients3
DIETARY FRUCTOSE ON BROILERS
1199
TABLE 2. Effect of adding high fructose corn syrup (HFCS) to broiler chick diets (Experiment 1) Percent HFCS 0
5
10
15
Body weight (BW) gain, g Feed intake, g/bird/day Feed:gain, g/g Liver weight, g/100 g BW Kidney weight, g/100 g BW Plasma uric acid, mg/dL
537.6 b 38.9 b 1.52 2.79 .87 b 4.47 b
574.2 a 41.2 a 1.51 2.89 92ab 4.71b
575.2 a 41.7a 1.52 2.82 .87 b 5.70 a b
581.4 a 42.7 a 1.54 2.96 1.00a 6.21 a
68.64 5.86 8.87
69.85 5.07 10.34
69.30 5.28 11.32
69.88 5.07 10.61
Body composition Moisture, % Lipid, % Liver lipid, %
a,b Values within a row with different superscripts differ significantly (P<.05).
the control diet. Mean kidney weights of birds fed the 10% level of HFCS was not different from controls. We have no explanation for this response. No differences were found among treatments in moisture and lipid content of the body. The diet containing 15% HFCS produced higher (P^.05) plasma uric acid values than the control diet or the diet containing 5% HFCS (Table 2). There were no significant increases in liver lipid, carcass moisture or carcass lipid content as a result of feeding HFCS.
RESULTS
Experiment 1. Body weight gain and feed intake were greater (P=£.05) for birds fed fructose diets than for those fed the control diet (Table 2). There were no significant differences in body weight gain and feed intake results among treatments that could be attributed to dietary level of HFCS. Also no significant differences were found among treatments for feed conversion. Mean liver weights by treatment, expressed as grams of liver per 100 g body weight (BW), were not significantly different. However, livers of chicks fed HFCS were slightly heavier, but not significantly (P«.05). Adding HFCS at 15% in the diet resulted in heavier (P^.05) kidney than those of control birds. Kidneys (grams per 100 g BW) were 5.7% heavier for birds fed the 5% HFCS diet and 14.9% heavier for those fed the 15% HFCS diet when compared with those fed
Experiment 2. Body weight gains, feed intake, and feed conversion values (Table 3) were similar to those obtained in Experiment 1 (Table 2). Substituting 4, 6, or 15% HFCS resulted in an improvement (P=£.05) in BW gain when compared with feeding the control diet. Although there was no significant difference in feed intake among treat-
TABLE 3. Effect of adding high fructose com syrup (HFCS) to broiler chick diets (Experiment 2) Percent HFCS Variable Body weight (BW) gain, g Feed intake, g/bird/day Feed:gain Liver weight, g/100 g BW Kidney weight, g/100 g BW
15 528 a 38.4 1.52ab 2.97a .95
551ab
40.7 1.55 a 3.05 a b .92
568 b 40.2 1.48ab 3.33b .97
Values within a row with different superscripts differ significantly (P<.05).
563 b 38.9 1.45 b 3.16 a b .97
561b 41.5 1.55a 3.29 b 1.00
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Variable
MILES ET AL.
1200
DISCUSSION
This study was designed primarily to determine whether feeding fructose from HFCS in the diet of broiler chicks for 21 days would affect growth. Substituting HFCS for 15% of corn in the diets for Experiments 1 and 2 did not adversely affect feed intake. However, a significant increase in feed intake resulted by adding 5, 10, or 15% HFCS to diets in Experiment 1. This increase in intake may have resulted from an over-estimation of the metabolizable energy value assigned to HFCS. However, this assumption is not reflected in the feed to gain ratio since there were no differences among treatment groups. Halpern (1963) and Gentle (1972) indicated that poultry are generally insensitive to sweet stimuli. Therefore, the increases in feed intake observed in both experiments were not considered to result from taste. One explanation of why chicks fed the HFCS consumed more feed may have been due to the physical texture of the diet. It was observed that when HFCS was added and mixed into the diet the feed particles had a tendency to adhere to each other. The resulting diet consistency was that of crumbles. This observation was especially pronounced in the diet containing the 15% HFCS. Mixing 15% HFCS into the diet resulted in a feed that had a sticky consistency. However, after 24 h the stickiness disappeared. The metabolism of fructose and glucose by the avian liver follows different intracellular pathways, initially. A large portion of fructose that is absorbed from the intestine is used by the liver (Leveille, et al., 1971). Therefore, it would be expected that large amounts of fructose or sucrose in the diet would alter liver weight and composition. Fructose stimulates the rate of
respiration in avian liver slices more than glucose. In vitro lipogenesis in liver slices is greater for fructose than glucose (Hawkins and Heald, 1966; Pearce, 1970). Pearce (1970) was able to confirm that fructose caused increased lipogenesis but was unable to find increased specific activity in lipogenic enzymes following short-term (4 days) feeding of fructose. In a more recent publication Pearce (1980) reported that enzymes in rats, but not chicks, appeared to respond to long-term fructose feeding as determined by the increased activities of the two enzymes, pyruvate kinase and isocitrate dehydrogenase. Vrana and Fabry (1983) also reported that a high intake of fructose or sucrose by rats resulted in increased liver weight and altered liver morphology. Data collected in this present study agree with those published previously regarding dietary fructose and its influence on liver weight. When expressed as g liver/100 g BW a nonsignificant but consistent increase in liver weight resulted from adding 5, 10 or 15% HFCS in Experiment 1. In Experiment 2, a significant increase in liver weight resulted from feeding 4 and 15% HFCS. The increase in kidney weight which resulted from feeding fructose in the present study has been confirmed in other species. Boot-Hanford and Heath (1981) fed rats sucrose and fructose based diets and reported increased kidney weights. These authors showed that the increase in kidney weight produced by feeding sucrose was due primarily to the fructose moiety of sucrose since kidney weight did not increase when glucose was fed alone. Similar research by Hall and Hall (1966), Allen and Leahy (1966), Bender and Thadani (1970), and Kazdova et al. also provides evidence that feeding either fructose or sucrose results in increased kidney size. The increase in kidney weight has been attributed to hyperplasia as indicated by increased deoxyribonucleic acid (DNA) synthesis. It has been suggested by several researchers that the increase in kidney weight is an adaptive increase of the body's capacity to handle a relatively uncommon nutrient. Fructose was probably never a major metabolite for poultry. To our knowledge, this is the first report of increased kidney size in poultry that resulted from feeding fructose. Administering fructose either orally or intravenously results in increased uric acid levels in serum (Maenpaa et al., 1968; Stirpe, et al., 1970; Emmerson, 1974; and Brodan et al.,
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ment groups, birds fed HFCS consumed a slightly greater amount of feed. Substituting 6% HFCS in the diet improved (P=£ .05) feed conversion when compared with results of feeding diets containing 2 and 15% HFCS. Liver weights of the 4 and 15% HFCS groups were heavier (P=s.05) than those of the unsupplemented group (Table 3). Average kidney weight from chicks fed the highest level of HFCS was identical to that obtained for chicks fed the highest levels of HFCS in Experiment 1. However, due to the increased kidney weight in the control birds no significant differences were found among treatments.
DIETARY FRUCTOSE ON BROILERS
ACKNOWLEDGMENT
The authors would like to thank the A. E. Staley Co., Decatur, Illinois, for furnishing the high fructose corn syrup used in this study. REFERENCES Allen, R.J.L., and J. S. Leahy, 1966. Some effects of dietary dextrose, fructose, liquid glucose and sucrose in the adult male rat. Br. J. Nutr. 20:339-347. Bender, A. E., and P. V. Thadani, 1970. Some metabolic effects of dietary sucrose. Nutr. Metab. 12:22-39. Brodan, V.,E. K. Brodanova.J. Filip, and J. Pechar, 1975. Ammonia and uric acid formation after rapid intravenous fructose administration to healthy subjects and patients with compensated cirrhosis of the liver. Nutr. Metab. 19:233-241. Boot-Handford, R. P., and H. Heath, 1981. The effect of dietary fructose and diabetes on the rat kidney. Br. J. Exp. Pathol. 62:398^06. Emmerson, H., 1974. Effect of oral fructose on urate production. Ann. Rheum. Dis. 33:276-280.
Gentle, M. J., 1972. Taste preference in the chicken. Br. Poult. Sci. 13:141-155. Hall, C. E., and D. Hall, 1966. Comparative effectiveness of glucose and sucrose enhancement of hyperalimentation and salt hypertension. Proc. Soc. Exp. Biol. Med. 123:370-374. Halpem, B. P., 1963. Gustatory nerve responses in the chicken. Am. J. Physiol. 203:541-544. Hawkins, R. A., and P. J. Heald, 1966. Lipid metabolism in the laying hen. IV. The synthesis of triglycerides by slices of avian liver in vitro. Biochim. Biophys. Acta 116:41-55. Kazdova, L., A. Vrana, and P. Fabry, 1976. Effect of dietary fructose on the nucleic acid content and DNA synthesis in rat liver and kidneys. Physiol. Bohemoslov. 25:264. Leveille, G. A.,T. K. Akinbami, andC. O. Ikediobi, 1971. Fructose absorption and metabolism by the growing chick. Soc. Exp. Biol, and Med. 135:483-486. Maenpaa, P. K., K. O. Ravio, andM. P. Kekomaki, 1968. Liver adenine nucleotides: fructose induced depletion and its effect of protein synthesis. Science 161:12531254. Miles, R. D., 1983. Molasses in non-ruminant nutritionpoultry Pages 27-62 in: Association, West Des Moines, IA. National Research Council, 1977. Nutrient Requirements of Domestic Animals. I. Nutrient Requirements of Poultry. 7th ed. Natl. Acad. Sci., Washington, DC. Pearce, J., 1980. A comparison of the response of hepatic enzyme activity in the domestic fowl (Gallus domesticus) and the rat (Rattus norvegicus) to the feeding of diets containing large proportions of glucose and fructose. Comp. Biochem. Physiol. 22:313-317. Pearce, J., 1970. The effects of dietary fructose and glucose on hepatic lipogenesis in the domestic fowl. Int. J. Biochem. 1:306-312. SAS Institute Inc., 1982. SAS User'sGuide: Statistics. 1982 ed., SAS Institute Inc., Cary, NC. Stirpe, F., E. Delia Corte, E. Bonetti, A. Abbondanza, A. Abbat, and F. De Stefano, 1970. Fructose-induced hyperuricemia. Lancet 2:1310. Vrana, A., and P. Fabry, 1983. Metabolic effects of high sucrose or fructose intake. World Rev. Nutr. Diet. 42:56-101. Waldroup, P. W., 1981. Use of molasses and sugars in poultry feeds. World's Poult. Sci. J. 37:193-202.
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1975). Since uric acid is the major nitrogenous waste product in the chick it was of interest to us to determine if feeding fructose would result in a higher uric acid level in plasma. In a manner similar to results of previous studies on other species, plasma uric acid was found to increase in a linear fashion as dietary fructose was increased (Table 2). Adding HFCS to the diet at the 15% level resulted in a significant (P«.05) increase in plasma uric acid when compared to the other treatments. The present study has demonstrated that the broiler chick can utilize up to 15% HFCS in the diet. Increased liver and kidney size and higher plasma uric acid levels produced by feeding HFCS indicate that the chick also responds to dietary fructose supplementation in a similar fashion as has been reported for other species.
1201
1987 Poultry Science 66:1197-1201 INTRODUCTION
Carbohydrates make up the major energy component of poultry diets. The carbohydrates vary in form from complex molecules such as starch and cellulose to the more simple di- and monosaccharides. Several studies have documented the use of sucrose in poultry diets but very little attention has been given to the use of fructose. Waldroup (1981) and Miles (1983) reviewed the literature regarding molasses and sugar incorporation into poultry diets. Fructose is considered to be the sweetest of all natural sugars and together with glucose is a component of the disaccharide sucrose. Fructose exists naturally in the free form or may be found in polymerized forms in a variety of fruits and vegetables. Not until recently has fructose become available in large quantities from the commercial hydrolysis and enzymatic inversion of corn starch. This development in technology has increased interest in the commercial use of fructose as a dietary carbohydrate.
"Florida Agricultural Experiment Station Journal Series Number 7205. department of Poultry Science. department of Animal Science. 4 Address correspondence to: Agricultural Research and Education Center, Live Oak, Florida 32060.
The present study was carried out to investigate the effects of feeding fructose from highfructose (HFCS) to broiler-type chicks and to determine if feeding fructose would result in an increase in kidney and liver size and elevated plasma uric acid. These three effects have been reported previously in the literature when fructose was fed to other species. MATERIALS AND METHODS
Two experiments were conducted using Cobb feather-sexed chicks. In each experiment chicks were sexed at one day of age and four males and four females were randomly assigned to each replicate in thermostatically controlled, electrically heated Petersime battery brooders with raised wire floors. Chicks were maintained on a 24-h constant-light schedule. Each experiment was conducted for 21 days. All experimental diets and tap water were offered ad libitum throughout the experimental period. In Experiment 1, 384 chicks were weighed and randomly assigned to four treatment groups with 12 replicates of 8 chicks each per treatment. The corn-soybean meal-based experimental diets (Table 1) were formulated to provide the nutrient requirements of growing chicks according to the National Research Council (1977). High-fructose corn syrup furnished dietary fructose and was substituted for corn at the levels
1197
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 7, 2015
ABSTRACT The effect of feeding various levels of dietary fructose, furnished by high fructose corn syrup (HFCS), to broiler-type chicks housed in Petersime batteries was studied in two experiments. In experiment 1, HFCS was added to a corn-soybean meal basal diet at levels of 0, 5, 10, and 15%. In Experiment 2, HFCS was added to the diet at levels of 0, 2, 4, 6, and 15%. In both experiments diets were isocaloric and isonitrogenous. In Experiment 1, chicks fed HFCS consumed more feed (P*.05) and grew more rapidly (P=£.05) than chicks fed the control diet. No differences in the feed to gain ratio were observed among treatments. Feeding HFCS resulted in non-significantly higher liver weight and percent liver lipid. Values for kidney weights and plasma uric acid were higher (P=s.05) in chicks fed 15% HFCS. In Experiment 2, adding 4, 6, and 15% HFCS resulted in more rapid growth (Ps.05). No significant differences were observed in feed intake and kidney weights. Chicks fed the 15% HFCS diet had heavier (Ps.05) livers. (Key words: fructose, broilers performance, liver weight, plasma uric acid)
1198
MILES ET AL. TABLE 1. Composition of experimental diets (Experiment 1) Treatment number
Dietary ingredients
1
1
2
55.40 37.25
49.10 38.35 5.00 3.70
3
4
42.85 39.50 10.00 3.80
36.60 40.65 15.00 3.90
- (%)
Calculated analyses4 Crude protein, % Metabolizable energy, kcal/kg Ca, % P, % 1
As-fed basis.
2
High Fructose Corn Syrup.
3.50 .15
.15
.15
.15
1.60 1.20
1.60 1.20
1.60 1.20
1.60 1.20
.40 .50
.40 .50
.40 .50
.40 .50
100.00
100.00
100.00
100.00
23.00 3,070
23.00 3,070
23.00 3,070
23.00 3,070
.92 .44
.92 .44
.92 .44
.92 .44
3 Supplied the following activities per kilogram of diet: vitamin A, 6,600 IU; vitamin D 3 , 2,200 ICU; menadione dimethylpyrimidinol bisulfite, 2.2 mg; riboflavin, 4.4 mg; pantothenic acid, 13.2 mg; niacin, 39.6 mg; choline chloride, 499.4 mg; vitamin B 1 2 , .022 mg; ethoxyquin, .0125%; manganese, 60 mg; iron, 50 mg; copper, 6 mg; iodine, 1.1 mg; and zinc, 35 mg. 4
National Research Council, 1977.
of 0, 5, 10, and 15%. Each diet was formulated to be isocaloric and isonitrogenous. The HFCS contained 80% sugars and 20% moisture (90% fructose on a dry matter basis). Since no metabolizable energy value for HFCS could be found for poultry the value for corn (NRC, 1977) was used. At the termination of the experiment, chicks were weighed individually and feed consumption was determined on a per pen basis. Fourteen male chicks from each treatment were selected randomly. Blood was collected by anterior cardiac puncture and plasma was collected for analysis of uric acid. The liver and both kidneys from each chick were also removed, blotted, and weighed. Livers were frozen until lipid analysis. In addition, eight males with similar body weights from each treatment group were selected, killed, and scalded. The feathers and entire digestive tract were removed and the carcasses were frozen for moisture and lipid analysis. A 3 to 4-g sample of minced homogenized carcass was dried for moisture determination and the lipid content of dried sample
was then determined by Soxhlet extraction with petroleum ether. In Experiment 2, 240 chicks were weighed and randomly assigned to five treatment groups with six replicates of eight chicks each per treatment. The levels of HFCS fed were 0, 2, 4, 6, and 15%, respectively. These levels were selected to confirm the results in Experiment 1 and to determine if dietary levels of HFCS below 5% would result in increased growth and feed intake. The basal diet used in Experiment 2 was identical in composition to the basal diet in Experiment 1. All diets were again formulated to be isocaloric and isonitrogenous. At the termination of the experiment (21 days) 16 male chicks were randomly selected from each treatment group. Chicks were weighed, killed, and their liver and kidneys removed and weighed. Data collected in both experiments were analyzed by analysis of variance; significant difference among means were determined by Duncan's multiple range test (SAS Institute Inc., 1982).
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 7, 2015
Corn, ground yellow Soybean meal, dehulled HFCS2 Corn oil Dl-methionine Dicalcium phosphate (22% Ca, 18.5% P) Limestone, ground Salt, iodized Micro ingredients3
DIETARY FRUCTOSE ON BROILERS
1199
TABLE 2. Effect of adding high fructose corn syrup (HFCS) to broiler chick diets (Experiment 1) Percent HFCS 0
5
10
15
Body weight (BW) gain, g Feed intake, g/bird/day Feed:gain, g/g Liver weight, g/100 g BW Kidney weight, g/100 g BW Plasma uric acid, mg/dL
537.6 b 38.9 b 1.52 2.79 .87 b 4.47 b
574.2 a 41.2 a 1.51 2.89 92ab 4.71b
575.2 a 41.7a 1.52 2.82 .87 b 5.70 a b
581.4 a 42.7 a 1.54 2.96 1.00a 6.21 a
68.64 5.86 8.87
69.85 5.07 10.34
69.30 5.28 11.32
69.88 5.07 10.61
Body composition Moisture, % Lipid, % Liver lipid, %
a,b Values within a row with different superscripts differ significantly (P<.05).
the control diet. Mean kidney weights of birds fed the 10% level of HFCS was not different from controls. We have no explanation for this response. No differences were found among treatments in moisture and lipid content of the body. The diet containing 15% HFCS produced higher (P^.05) plasma uric acid values than the control diet or the diet containing 5% HFCS (Table 2). There were no significant increases in liver lipid, carcass moisture or carcass lipid content as a result of feeding HFCS.
RESULTS
Experiment 1. Body weight gain and feed intake were greater (P=£.05) for birds fed fructose diets than for those fed the control diet (Table 2). There were no significant differences in body weight gain and feed intake results among treatments that could be attributed to dietary level of HFCS. Also no significant differences were found among treatments for feed conversion. Mean liver weights by treatment, expressed as grams of liver per 100 g body weight (BW), were not significantly different. However, livers of chicks fed HFCS were slightly heavier, but not significantly (P«.05). Adding HFCS at 15% in the diet resulted in heavier (P^.05) kidney than those of control birds. Kidneys (grams per 100 g BW) were 5.7% heavier for birds fed the 5% HFCS diet and 14.9% heavier for those fed the 15% HFCS diet when compared with those fed
Experiment 2. Body weight gains, feed intake, and feed conversion values (Table 3) were similar to those obtained in Experiment 1 (Table 2). Substituting 4, 6, or 15% HFCS resulted in an improvement (P=£.05) in BW gain when compared with feeding the control diet. Although there was no significant difference in feed intake among treat-
TABLE 3. Effect of adding high fructose com syrup (HFCS) to broiler chick diets (Experiment 2) Percent HFCS Variable Body weight (BW) gain, g Feed intake, g/bird/day Feed:gain Liver weight, g/100 g BW Kidney weight, g/100 g BW
15 528 a 38.4 1.52ab 2.97a .95
551ab
40.7 1.55 a 3.05 a b .92
568 b 40.2 1.48ab 3.33b .97
Values within a row with different superscripts differ significantly (P<.05).
563 b 38.9 1.45 b 3.16 a b .97
561b 41.5 1.55a 3.29 b 1.00
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 7, 2015
Variable
MILES ET AL.
1200
DISCUSSION
This study was designed primarily to determine whether feeding fructose from HFCS in the diet of broiler chicks for 21 days would affect growth. Substituting HFCS for 15% of corn in the diets for Experiments 1 and 2 did not adversely affect feed intake. However, a significant increase in feed intake resulted by adding 5, 10, or 15% HFCS to diets in Experiment 1. This increase in intake may have resulted from an over-estimation of the metabolizable energy value assigned to HFCS. However, this assumption is not reflected in the feed to gain ratio since there were no differences among treatment groups. Halpern (1963) and Gentle (1972) indicated that poultry are generally insensitive to sweet stimuli. Therefore, the increases in feed intake observed in both experiments were not considered to result from taste. One explanation of why chicks fed the HFCS consumed more feed may have been due to the physical texture of the diet. It was observed that when HFCS was added and mixed into the diet the feed particles had a tendency to adhere to each other. The resulting diet consistency was that of crumbles. This observation was especially pronounced in the diet containing the 15% HFCS. Mixing 15% HFCS into the diet resulted in a feed that had a sticky consistency. However, after 24 h the stickiness disappeared. The metabolism of fructose and glucose by the avian liver follows different intracellular pathways, initially. A large portion of fructose that is absorbed from the intestine is used by the liver (Leveille, et al., 1971). Therefore, it would be expected that large amounts of fructose or sucrose in the diet would alter liver weight and composition. Fructose stimulates the rate of
respiration in avian liver slices more than glucose. In vitro lipogenesis in liver slices is greater for fructose than glucose (Hawkins and Heald, 1966; Pearce, 1970). Pearce (1970) was able to confirm that fructose caused increased lipogenesis but was unable to find increased specific activity in lipogenic enzymes following short-term (4 days) feeding of fructose. In a more recent publication Pearce (1980) reported that enzymes in rats, but not chicks, appeared to respond to long-term fructose feeding as determined by the increased activities of the two enzymes, pyruvate kinase and isocitrate dehydrogenase. Vrana and Fabry (1983) also reported that a high intake of fructose or sucrose by rats resulted in increased liver weight and altered liver morphology. Data collected in this present study agree with those published previously regarding dietary fructose and its influence on liver weight. When expressed as g liver/100 g BW a nonsignificant but consistent increase in liver weight resulted from adding 5, 10 or 15% HFCS in Experiment 1. In Experiment 2, a significant increase in liver weight resulted from feeding 4 and 15% HFCS. The increase in kidney weight which resulted from feeding fructose in the present study has been confirmed in other species. Boot-Hanford and Heath (1981) fed rats sucrose and fructose based diets and reported increased kidney weights. These authors showed that the increase in kidney weight produced by feeding sucrose was due primarily to the fructose moiety of sucrose since kidney weight did not increase when glucose was fed alone. Similar research by Hall and Hall (1966), Allen and Leahy (1966), Bender and Thadani (1970), and Kazdova et al. also provides evidence that feeding either fructose or sucrose results in increased kidney size. The increase in kidney weight has been attributed to hyperplasia as indicated by increased deoxyribonucleic acid (DNA) synthesis. It has been suggested by several researchers that the increase in kidney weight is an adaptive increase of the body's capacity to handle a relatively uncommon nutrient. Fructose was probably never a major metabolite for poultry. To our knowledge, this is the first report of increased kidney size in poultry that resulted from feeding fructose. Administering fructose either orally or intravenously results in increased uric acid levels in serum (Maenpaa et al., 1968; Stirpe, et al., 1970; Emmerson, 1974; and Brodan et al.,
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ment groups, birds fed HFCS consumed a slightly greater amount of feed. Substituting 6% HFCS in the diet improved (P=£ .05) feed conversion when compared with results of feeding diets containing 2 and 15% HFCS. Liver weights of the 4 and 15% HFCS groups were heavier (P=s.05) than those of the unsupplemented group (Table 3). Average kidney weight from chicks fed the highest level of HFCS was identical to that obtained for chicks fed the highest levels of HFCS in Experiment 1. However, due to the increased kidney weight in the control birds no significant differences were found among treatments.
DIETARY FRUCTOSE ON BROILERS
ACKNOWLEDGMENT
The authors would like to thank the A. E. Staley Co., Decatur, Illinois, for furnishing the high fructose corn syrup used in this study. REFERENCES Allen, R.J.L., and J. S. Leahy, 1966. Some effects of dietary dextrose, fructose, liquid glucose and sucrose in the adult male rat. Br. J. Nutr. 20:339-347. Bender, A. E., and P. V. Thadani, 1970. Some metabolic effects of dietary sucrose. Nutr. Metab. 12:22-39. Brodan, V.,E. K. Brodanova.J. Filip, and J. Pechar, 1975. Ammonia and uric acid formation after rapid intravenous fructose administration to healthy subjects and patients with compensated cirrhosis of the liver. Nutr. Metab. 19:233-241. Boot-Handford, R. P., and H. Heath, 1981. The effect of dietary fructose and diabetes on the rat kidney. Br. J. Exp. Pathol. 62:398^06. Emmerson, H., 1974. Effect of oral fructose on urate production. Ann. Rheum. Dis. 33:276-280.
Gentle, M. J., 1972. Taste preference in the chicken. Br. Poult. Sci. 13:141-155. Hall, C. E., and D. Hall, 1966. Comparative effectiveness of glucose and sucrose enhancement of hyperalimentation and salt hypertension. Proc. Soc. Exp. Biol. Med. 123:370-374. Halpem, B. P., 1963. Gustatory nerve responses in the chicken. Am. J. Physiol. 203:541-544. Hawkins, R. A., and P. J. Heald, 1966. Lipid metabolism in the laying hen. IV. The synthesis of triglycerides by slices of avian liver in vitro. Biochim. Biophys. Acta 116:41-55. Kazdova, L., A. Vrana, and P. Fabry, 1976. Effect of dietary fructose on the nucleic acid content and DNA synthesis in rat liver and kidneys. Physiol. Bohemoslov. 25:264. Leveille, G. A.,T. K. Akinbami, andC. O. Ikediobi, 1971. Fructose absorption and metabolism by the growing chick. Soc. Exp. Biol, and Med. 135:483-486. Maenpaa, P. K., K. O. Ravio, andM. P. Kekomaki, 1968. Liver adenine nucleotides: fructose induced depletion and its effect of protein synthesis. Science 161:12531254. Miles, R. D., 1983. Molasses in non-ruminant nutritionpoultry Pages 27-62 in: Association, West Des Moines, IA. National Research Council, 1977. Nutrient Requirements of Domestic Animals. I. Nutrient Requirements of Poultry. 7th ed. Natl. Acad. Sci., Washington, DC. Pearce, J., 1980. A comparison of the response of hepatic enzyme activity in the domestic fowl (Gallus domesticus) and the rat (Rattus norvegicus) to the feeding of diets containing large proportions of glucose and fructose. Comp. Biochem. Physiol. 22:313-317. Pearce, J., 1970. The effects of dietary fructose and glucose on hepatic lipogenesis in the domestic fowl. Int. J. Biochem. 1:306-312. SAS Institute Inc., 1982. SAS User'sGuide: Statistics. 1982 ed., SAS Institute Inc., Cary, NC. Stirpe, F., E. Delia Corte, E. Bonetti, A. Abbondanza, A. Abbat, and F. De Stefano, 1970. Fructose-induced hyperuricemia. Lancet 2:1310. Vrana, A., and P. Fabry, 1983. Metabolic effects of high sucrose or fructose intake. World Rev. Nutr. Diet. 42:56-101. Waldroup, P. W., 1981. Use of molasses and sugars in poultry feeds. World's Poult. Sci. J. 37:193-202.
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1975). Since uric acid is the major nitrogenous waste product in the chick it was of interest to us to determine if feeding fructose would result in a higher uric acid level in plasma. In a manner similar to results of previous studies on other species, plasma uric acid was found to increase in a linear fashion as dietary fructose was increased (Table 2). Adding HFCS to the diet at the 15% level resulted in a significant (P«.05) increase in plasma uric acid when compared to the other treatments. The present study has demonstrated that the broiler chick can utilize up to 15% HFCS in the diet. Increased liver and kidney size and higher plasma uric acid levels produced by feeding HFCS indicate that the chick also responds to dietary fructose supplementation in a similar fashion as has been reported for other species.
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