Processing Grain Amaranth for Use in Broiler Diets1

Processing Grain Amaranth for Use in Broiler Diets 1 P. B. TILLMAN and P. W. WALDROUP2 Department of Animal Sciences, University of Arkansas, Fayetteville, Arkansas 72701 (Received for publication February 2, 1986)

1986 Poultry Science 65:1960-1964 INTRODUCTION

Grain amaranth is a potential alternative feed ingredient forpoultry rations (National Academy of Sciences, 1975, 1984). Due to its protein content, high lysine, and overall balance of amino acids (Downton, 1973), it could conceivably replace part of corn or soybean meal in broiler rations if price were competitive. The metabolizable energy content of grain amaranth for chicks is comparable to corn; it ranges from 3,000 (Laovoravit, 1982) to 3,475 (Connor et al., 1980) kcal/kg. Several toxic or "feed-refusal" factors have been reported for raw amaranth grain. These were suggested by Cheeke and Bronson (1980) to be saponins and phenolics. According to Hunziker (1952), grain amaranth does not contain saponins, but Cheeke and Bronson (1980) reported high saponin activity. Phenolics (primarily tannins and chlorogenic acid) are present in grain amaranth (Carlsson, 1980; Cheeke et al.,

1981; Afolabi et al., 1981; Becker et al., 1981) and were negatively correlated with weight gain of rats (Cheeke and Bronson, 1980). Conversely, Becker et al. (1981) indicated that tannin in amaranth was similar to that found in grains such as wheat, proso millet, and triticale. In studies by Connor et al. (1980) and Waldroup et al. (1985), autoclaving or heat treating grain amaranth destroyed toxic or "feed-refusal" factors. Because phenolics are heat labile, they would appear to be the primary cause for any observed toxic or "feed-refusal factors" in raw grain amaranth, but this has not been demonstrated conclusively. Limited data are available comparing different processing techniques for grain amaranth for use in poultry feeds. Therefore, studies were conducted to compare different autoclaving and extrusion methods for heat treating of grain amaranth to destroy toxic or "feed-refusal" factors. MATERIALS AND METHODS

Published with the approval of the Director, Arkansas Agricultural Experiment Station. 2 To whom correspondence should be addressed. 3 Nu-World Amaranth, Inc., Naperville, IL.

Two experiments were conducted to evaluate different methods of processing grain amaranth {Amaranthus cruentus*) for use in broiler diets. Amaranth was processed by either autoclaving

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ABSTRACT Two experiments were conducted in which grain amaranth (Amaranthus cruentus) was processed by autoclaving or extrusion and incorporated into broiler diets at 20 or 40%. In Experiment 1, grain was autoclaved for either 30, 60, or 90 min. Body weight gains and feed efficiencies were similar for the diet containing 20% grain amaranth autoclaved for 60 min and the corn-soybean meal control diet. At 40% inclusion, grain amaranth depressed growth significantly compared with the control diet regardless of autoclaving length. In Experiment 2, grain amaranth was processed by autoclaving and extruding. Only one of the feed efficiencies differed significantly from that of the control diet. Autoclaved amaranth, at 20% of the diet, produced body weight gains similar to the control diet regardless of processing length. When autoclaved amaranth was included into the diets at 40%, gains similar to those of chickens fed the control diet were obtained with processing lengths of either 30 or 45 min. Extruded amaranth, which was included only at 40%, produced body weight gains similar to those of chickens fed the control diet when extrusion was either "dry" or "normal". These studies indicate that broilers can utilize up to 40% grain amaranth in their rations if the amaranth is properly processed by either autoclaving or by extrusion. At present, there is no sufficient assay to determine if the toxic or feed refusal factor(s) present in amaranth have been sufficiently processed without resorting to chick feeding trials. Further studies are needed to identify these factors in grain amaranth. (Key words: amaranth, feed processing, broilers, alternate ingredients)

PROCESSING OF AMARANTH

4 Wenger X-25 extruder. Wenger Mixer Manufacturing Company, Sabetha, KS. 'Laboratory Model Pellet Mill, California Pellet Mill Co., Crawfordsville, IN.

laboratory as well as reported values (Downton, 1973; Harrold and Nalewaja, 1974, 1977; Harvo\detal., (1980; Connor et al., 1980; Betschart et al., 1981; Tovar and Carpenter, 1982; Uzo and Okorie, 1983). The assigned values agreed well with reports of Afolabi et al. (1981), Pant (1983) Tzachuk and Mellish (1977), and Cheeke etal. (1981). Diets were mixed in a small laboratory horizontal mixer, pelleted in a small pellet mill5 without added steam, and allowed to cool at room temperature. Due to the fine texture of the amaranth after grinding, diets containing 40% amaranth did not pellet well and were very powdery. Male broiler chicks were obtained from a commercial hatchery at 1 day of age and randomly assigned to pens in electrically heated Petersime battery brooders with raised wire floors. Six males were placed in each pen in Experiment 1 and five males in Experiment 2. Eight pens were fed the corn-soybean meal control diet, and four pens were fed each test diet in each experient. All birds received constant fluorescent illumination and were allowed free access to treatment diets and tap water from 0 to 21 days of age. At the end of 21 days, individual body weights and pen feed consumption were determined. Data were analyzed by leastsquares analysis of variance using the Statistical Analysis System (SAS Instititute, 1982). Differences among treatment means were determined by repeated t tests using probabilities generated by the least square means option of the general linear model procedure of SAS. RESULTS AND DISCUSSION

Experiment 1. Chicks fed diets containing 20% amaranth autoclaved for 60 min did not differ (P<.05) in body weight gain or feed utilization from chicks fed the corn-soybean meal control diet (Table 2). Shorter (30 min) or longer (90 min) autoclaving resulted in significantly (P< .05) reduced body weight gain and feed utilization when autoclaved diets were fed at the 20% inclusion. Addition of amaranth to the diet at 40% resulted in significant (P<.05) reduction in body weight gain and feed utilization as compared with those of chicks fed the corn-soybean meal control, regardless of autoclaving time (Table 2). Amaranth, autoclaved for 90 min and incorporated at 40% of the diet, supported body weight gains and feed utilization that were significantly lower (P<.05) than those attained on all

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or extrusion. Autoclave processing of the grain amaranth for both experiments was as follows: grain amaranth was finely ground and placed in 20 x 30 x 8-cm metal pans and autoclaved at 110 C for 30, 45, 60, or 90 min. The autoclaved amaranth was spread in thin layers on metal pans and put in a forced-draft oven (35 C) for 36 hr. Dried amaranth was reground and held at room temperature prior to mixing the experimental diets. For the second experiment, whole grain amaranth was extruded. Extrusion of the amaranth was by Farmland Industries of Kansas City, KS using a commercial steam extruder.4 Because of the startup procedure required for extrusion, three distinctly different products were produced. Part of the extruded amaranth was labeled as ' 'extruded dry'' because minimal steam was added during the process. A second portion of the amaranth had a "normal" amount of added steam ("extruded normal"), and the remainder had an excess of added steam ("extruded wet"). Extruded amaranth was dried immediately using a horizontal pellet cooler. Due to the excesssive steam added to it, the "wet" amaranth had to be dried further in a forced-draft oven (35 C for 36 hr). The "dry" and "normal" extruded amaranth were allowed to air dry prior to grinding. All extruded amaranth was finely ground after sufficient drying. Processed grain amaranth was incorporated into practical corn-soybean rations at 0, 20, and 40% to meet the minimum nutrient recommendations suggested by the National Research Council (1984). Dietary ingredient and nutrient values are in Table 1. Nutrient values assigned to grain amaranth in the linear programming matrix were as follows: metabolizable energy, 3,475 kcal/kg; protein, 16%; calcium, .185%; nonphytate phosphorus, .2%; sodium, .034%;arginine, 1.437%; glycine, 1.085; serine, .81%; histidine, .402%; isoleucine, .578%; leucine, .865%; lysine, .882%; methionine, .352%; cystine, .326%; phenylalanine, .659%; tyrosine, .532%; threonine, .532%; tryptophan, .195%; and valine, .643%. These nutrient values, as previously reported by Waldroup et al. (1985), were compiled using results from assays conducted in our

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TILLMAN AND WALDROUP TABLE 1. Composition of experimental diets Amaranth in diet

Ingredient

0%

40%

59.30 5.00 29.17

20.00 45.07 5.00 24.70

40.00 30.83 5.00 20.23

.58 .40 .40

.57 .31 .40

.56 .23 .40

4.29

3.11

1.94

.26 .50 .10

.24 .50 .10

.21 .50 .10

100.00

100.00

100.00

3,200.00 21.89 1.55

3,200.00 21.67 1.60

3,200.00 21.44 1.65

.55

Grain amaranth Yellow corn Meat and bone meal (50% protein) Soybean meal (48.5% protein) Ground limestone (38% Ca) Dicalcium phosphate (18.5% P; 21% Ca) Iodized salt Animal and vegetable fat DL-Methionine (98%) Vitamin premix 1 Trace minerals2 Calculated nutrient composition Metabolizable energy, kcal/kg Protein, % Arginine, % Histidine, % Isoleucine, % Leucine, % Lysine, % Methionine, % Phenylalanine, % Threonine, % Tryptophan, % Valine, % Glycine plus serine, % Methionine plus cystine, % Phenylalanine plus tyrosine, % Calcium, % Phosphorus (inorganic), % Sodium, % Chloride, %

.00

1.04 1.91 1.20

.54 .99

.53 .94

1.75 1.20

1.60 1.20

.62 .97 .86 .26

.60 .94 .83 .26

.59 .91 .79 .26

1.20 2.40

1.14 2.44

1.07 2.48

.93

.93

.93

1.86

1.78

1.71

.90 .45 .22 .32

.90 .45 .22 .31

.90 .45 .22 .30

1 Supplied per kilogram of diet: 6612 IU vitamin A; 2,204 ICU vitamin D 3 ; 6.6 IU vitamin E; 3.3 mg menadione; 5.5 mg riboflavin; 33 mg niacin; 8.8 mg pantothenic acid; 495 mg choline; 1.1 mg thiamine; 1.1 mg pyridoxine; .01 mg vitamin B „ ; .11 mg biotin; .66 mg folacin; 125 mg ethoxyquin; .1 mg selenium. 2

Supplied per kilogram of diet: 100 mg iron; 100 mg manganese; 100 mg zinc; 10 mg copper; 1 mg iodine.

other dietary treatments, suggesting that this grain was overcooked. Results of this experiment agree with the report of Waldroup et al. (1985). They found that inclusion of amaranth autoclaved at 60 min and incorporated into broiler diets at 20% grew as well and utilized feed as efficiently as those fed a corn-soybean meal control diet. From that experiment it was concluded that autoclaving times of 30 to 60 min improved the acceptance and utilization of amaranth by the broiler chicken. Experiment 2. Autoclaved amaranth incorporated into broiler diets at 20% of the diet supported body weight gains and feed utilization that did not differ (P<.05) from those of chickens fed the corn-soybean meal control (Table 3)

regardless of the time of autoclaving. When the amaranth was increased to 40% of the diet, body weight gains were numerically reduced compared with those of the control group; gains of chickens fed the amaranth autoclaved for 60 min were significantly reduced (P<.05). Feed utilization was also depressed in this group with significant reduction (P<.05) in feed utilization by chickens fed the diet containing amaranth that had been autoclaved for 45 min. Performance of chickens fed the diets containing extruded amaranth indicates that amaranth per se was not responsible for the reduced performance of chickens fed 40% autoclaved amaranth. Chickens fed diets that contained 40% "extruded dry" or "extruded normal" amaranth

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20%

PROCESSING OF AMARANTH

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TABLE 2. Effects of percent dietary inclusion and autoclaving time of grain amaranth on performance of male broiler chicks from 0 to 21 days (Experiment 1) Grain amaranth

Autoclaving time

(%)

min

0 20 20 20 40 40 40

0 30 60 90 30 60 90

N1

Body weight gain

Gain/feed

8 4 4 4 4 4 4

— 578 529 577 531 519 487 441

— .652 .618 .630 .604 .598 .575 .530

(g) — ± 10.6 a ± 15.0t> ± 15.0 a ± 15.0 b ± 15.0 b ± 15.0 b ± 15.0 C

(g/g) — ± .009 a ± ,012b ± .012 a b ± .012bc ± .012bc ± .012 c ± .012 d

a—d

had body weight gains and feed utilization that did not differ significantly (P>.05) from those of chickens fed the control diet (Table 3). Chickens fed diets containing 40% amaranth considered as "extruded wet" did not gain as well (P<.05) as those fed the control diet with numerically reduced feed utilization. Addition of excessive steam during extrusion caused this portion of the amaranth to pass through the extruder faster and therefore failed to inactivate the toxic or feed refusal factors present in amaranth. These results demonstrate that grain amaranth can be sucessfully included in the diet of broiler

chickens at levels up to 40% if properly processed by autoclaving or extruding. These findings are in agreement with the studies of Waldroup et al. (1985). More studies are needed to assess accurately the exact conditions needed for optimum processing. Until the exact nature of the toxic or refusal factor(s) is identified, it will be difficult to determine if amaranth is properly processed without resorting to feeding trials. REFERENCES Afolabi, A. D., O. L. Oke, and I. B. Umoh, 1981. Preliminary studies on the nutritive value of some cereal

TABLE 3. Effects of percent dietary inclusion and processing of grain amaranth on performance of male broiler chicks from 0 to 21 days (Experiment 2) Grain amaranth

Processing method

Processing conditions

n1

None Autoclaved Autoclaved Autoclaved Autoclaved Autoclaved Autoclaved Extruded Extruded Extruded

None 30 min 45 min 60 min 30 min 45 min 60 min Dry Normal Wet

8 4 4 4 4 4 4 4 4 4

(%) 0 20 20 20 40 40 40 40 40 40

Body weight gam — 507 529 471 504 468 461 425 504 513 433

(g) — ± 14.7 a b ± 20.8 a ± 20.8abc ± 20.8ab + 20.8abc ± 20.8bc ± 20.8 C ± 20.8ab ±20.8ab + 20.8 C

Gain/feed

.645 .627 .604 .641 .584 .547 .561 .585 .597 .575

(g/g) — ± .027 a ± .038ab ± .038ab ± .038ab ± .038ab ± .038 b ± .038 a b ± .038 a b ± .038ab + .038ab

' ' Least squares means (± standard error) within a column with a common superscript are not different (P<.05). 1

Number of replications (five males per replicate).

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Least squares means (± standard errors) within a column with a common superscript are not different (P<.05). 1 Number of replications (six males per replicate).

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grains. Nutr. Rep. Int. 24:389-394. Becker, R., E. L. Wheeler, K. Lorenz, A. E. Stafford, O. K. Grosjean, A. A. Betschart, and R. M. Saunders, 1981. A compositional study of amaranth grain. J. Food Sci. 46:1175-1180. Betschart, W. E., D. W. Irving, A. D. Shepard, and R. M. Saunders. 1981. Amaranthus cruentus: Milling characteristics, distribution of nutrients within seed components, and the effects of temperature on nutritional quality. J. Food Sci. 46:1181-1187. Carlsson, R., 1980. Quantity and quality of Amaranthus grain from plants in temperate, cold and hot, and subtropical climates-A review. Pages 48-58 in Proc. 2nd Amaranth Conf., Rodale Press, Inc., Emmaus, PA. Cheeke, P. R., and J. Bronson, 1980. Feeding trials with amaranthus grain, forage, and leaf protein concentrates. Pages 5-11 in Proc. 2nd Amaranth Conf., Rodale Press, Inc., Emmaus, PA. Cheeke, P. R., R. Carlsson, and G. 0 . Kohler, 1981. Nutritive value of leaf protein concentrates prepared from Amaranthus species. Can J. Anim. Sci. 61:199-204. Connor, J. K., R.J.W. Gartner, B. M. Runge, and R. N. Amos, 1980. Amaranthus edulis: An ancient food source re-examined. Aust. J. Exp. Agric. Anim. Husb. 20:156-161. Downton, W.J.S., 1973. Amaranthus edulis: a high lysine grain amaranth. World Crops 25:20-21. Harrold, R. L., D. L. Craig, J. D. Nalewaja, and B. B. North, 1980. Nutritive value of green or yellow foxtail, wild oats, wild buckwheat or redroot pigweed seed as determined with the rat. J. Anim Sci. 51:127-131. Harrold, R. L., and J. D. Nalewaja, 1974, Proximate and amino acid analysis of ergot and weed seeds. North Dakota Farm Res. 32(1):15-17.