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Effects of Overprocessing on the Nutritional Quality of Sunflower Meal
Effects of Overprocessing on the Nutritional Quality of Sunflower Meal YE ZHANG and CARL M. PARSONS1 Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801 ABSTRACT A 2-wk chick study was conducted to evaluate the effect of overprocessing on the in vivo nutritional quality and in vitro protein solubility in .2% KOH of solvent-extracted sunflower meal (SFM) containing 36% protein. The SFM was autoclaved at 121 C and 105 kPa for 0, 30, 60, or 90 min in Experiment 1 and for 0,10,20,30,40, or 60 min in Experiment 2. Corn-SFM diets containing 22% protein were fed to chicks from 8 to 17 d of age. Chick performance decreased in both experiments as autoclaving time of the SFM increased. Linear regression analysis of performance on autoclaving time yielded the equations Y = 126.7 - .32X (r2 = .94) for weight gain and Y = .615 .001X (r2 = .80) for feed efficiency in Experiment 1. A precision-fed cockerel digestibility assay using cecectomized birds indicated that true digestibility of amino acids in SFM decreased as autoclaving time increased. The effect of autoclaving on digestibility was greatest for Lys, wherein Lys digestibility in SFM was 86,54,43, and 35% when SFM was autoclaved for 0,30,60, or 90 min, respectively. Protein solubility of SFM in .2% KOH decreased from 64 to 51% as SFM was autoclaved from 0 to 60 min. The results indicated that protein solubility values of 60% or lower are indicative of overprocessing of SFM. {Key words: sunflower meal, protein solubility, amino acid digestibility, chick performance) 1994 Poultry Science 73:436-442
method for the production of SFM is prepress solvent-extraction of sunflower The worldwide production of sun- seeds. Because the processing involves flower meal (SFM) is large. In 1990, it was heating, it is possible that SFM could be estimated that world production of SFM overcooked. It has been shown that excess was 8.6 million metric tons, which ranked heating of soybean meal and canola meal fourth in oilseed production behind soy- decreases in vivo availability of some bean meal, cottonseed meal, and canola amino acids, particularly Lys (Hancock et meal, respectively (World Oilseed Situa- al, 1990; Parsons et al, 1992; Andersontion and Outlook, 1992). Thus, SFM is Hafermann et al, 1993). Thus, overprocessoften used in poultry rations. As reviewed ing of SFM could greatly affect its nutriby Zatari and Sell (1990) and Vieira et al. tional value because sunflower protein is (1992), high levels of SFM can be used very deficient in Lys. Indeed, Rad and successfully in broiler chicken and laying Keshavarz (1976) reported that the chemihen diets if adequate levels of dietary Lys cally determined available Lys content of and metabolizable energy are provided. SFM decreased when the processing temThe most common commercial processing perature was increased. Protein solubility in KOH has been reported to be a good indicator of reduced protein quality in overprocessed soybean Received for publication June 21, 1993. meal (Araba and Dale, 1990; Parsons et al, Accepted for publication October 4, 1993. 1991) and also was useful for detecting 1 To whom correspondence should be addressed at 284 Animal Sciences Laboratory, 1207 W. Gregory overprocessed canola meal (AndersonHafermann et al, 1993). However, its Drive, Urbana, IL 61801. INTRODUCTION
436
HEATING EFFECTS ON SUNFLOWER MEAL QUALITY
usefulness as an indicator of protein quality for overprocessed SFM has not been evaluated. The objectives of the present study were to determine the effect of overprocessing on in vivo protein quality of SFM and the usefulness of protein solubility in KOH as indicator of reduced in vivo protein quality due to overprocessing of SFM. MATERIALS AND METHODS Sunflower meal used in all experiments in this study was obtained as a single batch from a commercial solvent extraction processing plant. 2 To ensure that overprocessing of the SFM occurred, a thin layer (1.25 cm in depth) was placed on metal trays, covered tightly with aluminum foil, and autoclaved at 121 C and 105 kPa for increasing amounts of time from 0 to 90 min. Protein solubility of the processed SFM in .2% KOH was determined by the method described by Parsons et ah (1991). Amino acid concentrations in the SFM and excreta from the digestibility trials described below were determined in duplicate or triplicate using ion-exchange chromatography 3 following hydrolysis in 6 N HC1 for 22 h at 110 C (Spackman et ah, 1958). Analyses of Met and Cys were conducted separately following performic acid oxidation by the method of Moore (1963) except that samples were diluted with water and lyophilized to remove excess performic acid following the 16-h oxidation period. Crude protein levels were determined by the macroKjeldahl method (Association of Official Analytical Chemists, 1980). Experiments 1 and 2 were conducted to evaluate the effects of overprocessing on in vivo protein quality of SFM for chicks and to evaluate the KOH assay as an indicator of overprocessing. Male chicks, obtained by crossing New Hampshire males and Columbian Plymouth Rock females, were housed in thermostatically controlled starter batteries with raised
2
NationaI Sun Co., Enderlin, ND 58027. Beckman Model 6300 amino acid analyzer, Beckman Instruments Corp., Palo Alto, CA 93402. 3
437
wire floors and provided with water and feed for ad libitum consumption. Uniform light was provided 24 h / d . The chicks were fed a 24% CP corn-soybean meal diet during the first 7 d posthatching. After being deprived of feed overnight, chicks were weighed, wing-banded, and assigned to dietary treatments by the procedure of Sasse and Baker (1974). In Experiment 1, corn-SFM diets containing 22% CP (Table 1) were prepared from SFM autoclaved for 0, 30, 60, or 90 min. For comparison, a commercial cornsoybean meal diet containing 23% CP was also evaluated. In Experiment 2, corn-SFM diets were prepared from SFM autoclaved for 0, 10, 20, 30, 40, or 60 min. The cornSFM diets were formulated to be slightly deficient in Lys and SAA to increase sensitivity for detecting adverse effects of overprocessing on protein quality of SFM. Each of the diets in both experiments was fed to three replicate groups of six male chicks from 8 to 17 d posthatching. Body weight and feed intake of each replicate group were measured at the termination of the experiments, and weight gain and feed efficiency (gain:feed ratio) were calculated. Experiment 3 was conducted to determine the true digestibilities of amino acids in SFM autoclaved for 0, 30, 60, or 90 min. The precision-fed cockerel assay of Sibbald (1986), with some modifications, was used for determining the digestibility values. At 25 wk of age, Single Comb White Leghorn cockerels were cecectomized as previously described (Parsons, 1985) and were not used in digestibility trials for at least 8 wk following surgery. The birds were housed in individual cages with raised wire floors in an environmentally regulated room having a 16 h light:8 h dark photoperiod. Feed and water were provided for ad libitum consumption except when the birds were being used in a digestibility assay. Following 24 h of feed deprivation, five cockerels were given 30 g of a SFM sample via crop intubation. To estimate endogenous amino acid excretion, the same number of cockerels were deprived of feed for the duration of the digestibility assay. Excreta were quantitatively collected on plastic trays placed under each cage for 48 h. The excreta were frozen,
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ZHANG AND PARSONS
lyophilized, weighed, ground to pass through a 60-mesh screen, and analyzed for amino acid content as described previously. True digestibility of amino acids was calculated by the method of Sibbald (1979), with digestibility referring to the amount of dietary amino acid not appearing in the feces plus urine. The chick performance data, amino acid digestibility values, and KOH protein solubility values obtained in the experiments were analyzed by ANOVA for completely randomized designs (Steel and Torrie, 1980) using algorithms generated by the SAS Institute (1982). Differences between treatment means were assessed using the least significant difference test and single degree-of-freedom contrasts where meaningful (Steel and Torrie, 1980). Regression analysis was also used to evaluate the chick performance response
to autoclaving of SFM (Steel and Torrie, 1980). RESULTS The effects of autoclaving time on chick performance and protein solubility observed in Experiment 1 are shown in Table 2. Increasing autoclaving time resulted in a linear decrease (P < .05) in weight gain and feed efficiency, and a quadratic decrease in protein solubility. In comparison to the unautoclaved SFM, autoclaving for 30 min or more significantly reduced (P < .05) weight gain and protein solubility. Protein solubility decreased as SFM was autoclaved for 30 and 60 min, but no further reduction in protein solubility was observed when autoclaved for 90 min. Compared with the unautoclaved SFM, the reductions at 90 min were 23, 16, and
TABLE 1. Composition of the corn-sunflower meal basal diet and the corn-soybean meal diet Ingredients and analysis
Corn-sunflower meal basal diet
Corn-soybean meal diet -
Sunflower meal (36% CP) Soybean meal (48.5% CP) Alfalfa meal (17% CP) Menhaden fish meal (60% CP) Corn (7.65% CP) Corn oil Dicalcium phosphate Ground limestone Choline-Cl (60%) Iodized salt DL-methionine L-LysHCl Vitamin premix1 Trace mineral premix2 Calculated analysis3 CP MEn/ kcal/kg Methionine + cystine Lys Ca Available P
\/U)
52.90
33.085 10.00 1.35 1.50 .10 .40 .16 .33 .10 .075 22 3,008 .88 1.10 1.00 .45
37.00 1.00 2.00 51.925 4.00 2.20 1.00 .10 .40 .20 .10 .075 23.3 3,064 .91 1.41 1.07 .59
Provided per kilogram of diet: vitamin A (as vitamin A acetate), 4,400 IU; cholecalciferol (as activated animal sterol), 1,000 IU; vitamin E (as a-tocopheryl acetate), 11 IU; vitamin B12, .01 mg; riboflavin, 4.41 mg; dpantothenic acid, 10 mg; niacin, 22 mg; menadione sodium bisulfite, 2.33 mg. 2 Provided as milligrams per kilogram of diet: manganese, 75 from manganese oxide; iron, 75 from iron sulfate; zinc, 75 from zinc oxide; copper, 5 from copper sulfate; iodine, .35 from ethylene diamine dihydroiodide; selenium, .2 from sodium selenite. 3 Values for CP and amino acids are based on analytical values for corn, sunflower meal, and soybean meal and all other ingredient values are based on ingredient table values from the NRC (1984). The latter values for sunflower meal were the average of the values for solvent-extracted sunflower meal with and without hulls in the NRC (1984) table.
HEATING EFFECTS ON SUNFLOWER MEAL QUALITY
439
TABLE 2. Effect of autoclaving sunflower meal on chick performance and protein solubility, Experiment 1
Diet Corn-sunflower, 22% CP
Autoclaving time
Weight gain 1 ' 2
Gain:feed ratio1-2
(min) 0 30 60 90
(g)
teg)
127b 115= 108d 98 e 146= 2.0
.619** .577*>c .546cd .521 d .655= .017
Corn-soybean meal, 23% CP Pooled SEM
Protein solubility in .2% KOH 1 . 2
(%) 64 b 58= 51 d 51d 84= .8
a_e
Means within a column with no common superscript differ significantly (P < .05). 1 Values for weight gain and gain:feed ratio are means of three replicate groups of six male chicks from 8 to 17 d of age; average initial weight was 72.7 g. Values for protein solubility are for the sunflower meal or soybean meal and are means of triplicate determinations. Significant linear effect of autoclaving (P < .001) for weight gain and gain:feed ratio and significant quadratic effect (P <: .005) for protein solubility.
20% for weight gain, feed efficiency, and protein solubility, respectively. Chicks fed the corn-soybean meal diet performed better (P < .05) than chicks fed any of the corn-SFM diets. Experiment 2 was conducted to determine the effect of autoclaving times intermediate to those used in Experiment 1. Autoclaving SFM for 10, 20, or 30 min reduced chick performance (P < .05) to a similar extent (Table 3). There was a further decrease (P < .05) in chick perfor-
mance when SFM was autoclaved for 40 min, but no further reduction occurred at 60 min of autoclaving. The magnitude of these performance decreases due to autoclaving were comparable to those obtained in Experiment 1. Protein solubility in .2% KOH decreased linearly from 0 to 30 min of autoclaving. A further reduction in protein solubility was observed at 60 min of autoclaving. The effect of autoclaving time on total amino acid concentrations in SFM is
TABLE 3. Effect of autoclaving sunflower meal on chick performance and protein solubility. Experiment 2 Autoclaving time
Weight gain1-2-3
Gain:feed ratio1-2'3
Protein solubility1'2-4
(min)
(g)
(g:g)
0 10 20 30 40 60 Pooled SEM
131= 120bc 123 ab 12ibc H 2 cd 110d 3.3
.636"
(%) 65= 62b 59= 56d 55d 51*
a_
.608b .605bc .604>* .577cd .575d .009
«Means within a column with no common superscript differ significantly (P < .05). Values for weight gain and gain:feed ratio are means of three replicate groups of six male chicks from 8 to 17 d of age; average initial weight was 72.8 g. Values for protein solubility are means of triplicate determinations. 2 Linear effect of autoclaving (P < .01). 3 Single degree of freedom contrast of 10, 20, and 30 min vs 40 min was significant (P < .05). 4 Solubility of sunflower meal protein in .2% KOH. 1
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ZHANG AND PARSONS
TABLE 4. Effect of autoclaving on analyzed total amino acid concentrations in sunflower meal 1 Minutes autoclaved Amino acid
0
30
Aspartic acid Threonine Serine Glutamic acid Proline Glycine Cystine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Histidine Lysine Arginine
3.28 1.29 1.48 7.21 1.64 1.87 .56 1.87 .57 1.42 2.35 .76 1.61 .83 1.43 2.76
3.20 1.25 1.49 6.74 1.50 1.35 .55 1.67 .56 1.40 2.14 .73 1.52 .75 1.04 2.61
60
90
3.01 1.23 1.35 6.40 1.40 1.26 .54 1.58 .54 1.37 2.03 .72 1.48 .71 .89 2.48
3.00 1.25 1.36 6.50 1.47 1.22 .50 1.62 .52 1.36 2.05 .64 1.45 .71 .84 2.40
(%)
1 91.5% DM basis. Amino analyses performed in triplicate; mean coefficient of variation for amino acid analyses within samples was 3.8%.
shown in Table 4. Ninety minutes of autoclaving reduced the Lys concentration by 41% below that obtained for the unautoclaved meal (P < .05). Autoclaving had much less effect on the concentration of the other amino acids. The average reductions for these other amino acids when autoclaved for 30, 60, or 90 min were 7, 12, and 12%, respectively, compared with 27, 38, and 41% for Lys, respectively. As shown in Table 5, the true digestibility of Lys, expressed as a proportion of the
analyzed Lys in the unautoclaved SFM, decreased markedly (P < .05) for each 30-min increase in autoclaving time (Experiment 3). The largest decrease occurred for the first 30 min of autoclaving. The digestibility of the analyzed Lys remaining after autoclaving was also significantly decreased as autoclaving time increased (P < .05). The effects of autoclaving on digestibility of other amino acids were less than those observed for Lys (Table 6). A significant decrease (P < .05) in digestibility was obtained only with valine at 30
TABLE 5. Effect of autoclaving on true digestibility of lysine in sunflower meal, Experiment 3 1
Autoclaving time (min) 0 30 60 90 Pooled SEM a_f
Digestibility as a proportion of analyzed Lys remaining after autoclaving
Digestibility as a proportion of analyzed Lys in unautoclaved sunflower meal
(%) 86^
86" 70b 67b 60c
54<*
43* 35f 2.1
Means with no common superscript differ significantly (P < .05). Values are means of five individual cecectomized cockerels.
HEATING EFFECTS ON SUNFLOWER MEAL QUALITY
441
TABLE 6. Effect of autoclaving on true digestibility of amino acids in sunflower meal, Experiment 3 1 Minutes autoclaved Amino acid
0
30
Threonine Cystine Valine Methionine Isoleucine Leucine Phenylalanine Histidine Arginine
87^ 81* 87= 85" 86* 87* 9ia 82* 93* 87
81*b 77ab 78 b 82*b 85* 82* 91* 76* 92* 83
60
90
80b 73b
76 b 71b 70c 78 b 76 b 68b 81b 66' 82c 74
, , Pooled SEM
(%)
X
73<:
79 b 78b 72b 84b 70bc
86b 77
1.8 2.6 1.0 1.5 1.4 1.4 1.0 2.2 .7
a_c
Means within a row with no common superscript differ significantly (P < .05). Values are means of five individual cecectomized cockerels expressed as a percentage of the amino acid content in the unautoclaved sunflower meal. 1
min of autoclaving whereas digestibility of all amino acids listed in Table 6 was decreased at 60 min of autoclaving. However, only arginine digestibility was reduced further (P < .05) at 90 min of autoclaving. DISCUSSION The present study showed that overprocessing by autoclaving reduced in vivo protein quality of SFM. Overprocessing decreased both growth performance of chicks and digestibility of amino acids in adult cockerels. That the effects of overheating were greater for Lys than other amino acids is in agreement with recent studies on soybean meal by Parsons et al. (1992) and for canola meal by AndersonHafermann et al. (1993). The large decrease in Lys digestibility can probably be attributed largely to Maillard reaction products formed during autoclaving (Hurrell, 1990). The reduction in Lys digestibility when expressed both as a proportion of the analyzed Lys in the unautoclaved SFM and as a proportion of the analyzed Lys remaining after autoclaving indicates that a wide range of Maillard reaction products may have been produced. The large decreases in analyzed Lys by autoclaving indicated Lys destruction due to formation of advanced Maillard reaction
products. The reduced digestibility of the analyzed Lys remaining after autoclaving indicated formation of early Maillard reaction products, which are recoverable during amino acid analysis (acid hydrolysis) but are not available for in vivo protein synthesis (Hurrell, 1990). The reduction in chick growth performance due to autoclaving SFM (Table 2) was somewhat less than expected based on the decrease in Lys digestibility due to autoclaving. The amount of digestible Lys in the corn-SFM diet decreased by .38% as the SFM was autoclaved for 90 min. Based on the results of Han and Baker (1991), the growth depression from a .38% decrease in dietary digestible Lys should have exceeded that observed herein. These observations suggest that the digestibility assay may have underestimated the amount of SFM Lys that was available to the chicks. The results herein clearly showed that protein solubility in KOH decreased as SFM was overcooked. Similar results have been reported for soybean meal (Araba and Dale, 1990; Parsons et al, 1991) and for canola meal (Anderson-Hafermann et al., 1993). These results indicated that, as for soybean meal and canola meal, protein solubility in KOH is a useful index of overprocessing of SFM and protein solubility values of approximately 60% or
442
ZHANG AND PARSONS
lower are indicative of overprocessed SFM. Similar to observations for canola meal (Anderson-Hafermann et ah, 1993), the KOH assay for detecting overprocessing of SFM is probably not as sensitive as previously reported for soybean meal (Araba and Dale, 1990; Parsons et al, 1991). The reductions in protein solubility of soybean meal due to overheating in the latter studies were much greater than those observed herein for SFM. The reduced performance of chicks fed the com-SFM diet compared with the corn-soybean meal diet herein was probably and partially due to marginal deficiencies of protein, Lys, and SAA. Other factors may also have been involved, however, because previous studies have reported depressed performance of chicks fed diets high in SFM. Dietary levels of 15 to 20% SFM are well tolerated by broiler chickens, whereas higher levels often result in reduced growth performance (Waldroup et al, 1970; Rad and Keshavarz, 1976; Zatari and Sell, 1990). The level of 52.5% SFM used in the broiler diets herein greatly exceeded the levels found to be tolerable in the earlier broiler studies. In contrast, Vieira et al. (1992) recently found that laying hens could tolerate levels of SFM up to at least 40% of the diet.
REFERENCES Anderson-Hafermann, J. C , Y. Zhang, and C. M. Parsons, 1993. Effects of processing on the nutritional quality of canola meal. Poultry Sci. 72:326-333. Araba, M , and N. M. Dale, 1990. Evaluation of protein solubility as an indicator of overprocessing soybean meal. Poultry Sci. 69:76-83. Association of Official Analytical Chemists, 1980. Official Methods of Analysis. 13th ed. Association of Official Analytical Chemists, Washington, DC. Han, Y., and D. H. Baker, 1991. Lysine requirement of fast- and slow-growing broiler chicks. Poultry Sci. 70:2108-2114. Hancock, J. D., E. R. Peo, Jr., A. J. Lewis, and J. D. Crenshaw, 1990. Effects of ethanol extraction and duration of heat treatment of soybean flakes on the utilization of soybean protein by growing rats and pigs. J. Anim. Sci. 68:3233-3243.
Hurrell, R. F., 1990. Influence of the maillard reaction on the nutritional value of foods. Pages 245-258 in: The Maillard Reaction in Food Processing, Human Nutrition and Physiology. Birkhauser Verlag, Basel, Switzerland. Moore, S., 1963. On the determination of cystine as cysteic acid. J. Biol. Chem. 238:235-237. National Research Council, 1984. Nutrient Requirements of Poultry. 8th rev. ed. National Academy Press, Washington, DC. Parsons, C. M., 1985. Influence of cecectomy on digestibility of amino acids by roosters fed distillers dried grains with solubles. J. Agric. Sci. 104:469-472. Parsons, C. M., K. Hashimoto, K. J. Wedekind, and D. H. Baker, 1991. Soybean protein solubility in potassium hydroxide: an in vitro test of in vivo protein quality. J. Anim. Sci. 69:2918-2924. Parsons, C. M., K. Hashimoto, K. J. Wedekind, Y. Han, and D. H. Baker, 1992. Effect of overprocessing on availability of amino acids and energy in soybean meal. Poultry Sci. 71:133-140. Rad, F. H., and K. Keshavarz, 1976. Evaluation of the nutritional value of sunflower meal and the possibility of substitution of sunflower meal for soybean meal in poultry diets. Poultry Sci. 55: 1757-1765. SAS Institute, 1982. SAS® User's Guide: Statistics. Version 5 Edition. SAS Institute Inc., Cary, NC. Sasse, C. E., and D. H. Baker, 1974. Factors affecting sulfate-sulfur utilization by the young chick. Poultry Sci. 53:652-662. Sibbald, I. R., 1979. A bioassay for available amino acids and true metabolizable energy in feedstuffs. Poultry Sci. 58:668-673. Sibbald, I. R., 1986. The TME system of feed evaluation: methodology, feed composition data and bibliography. Technical Bulletin 1986-4E. Agriculture Canada, Ottawa, ON, Canada. Spackman, D. H., W. H. Stein, and S. Moore, 1958. Automatic recording apparatus for use in the chromatography of amino acids. Anal. Chem. 30:1190-1206. Steel, R.G.D., and J. H. Torrie, 1980. Principles and Procedures of Statistics. A Biometrical Approach. 2nd ed. McGraw-Hill Book Co., Inc., New York, NY. Vieira, S. L., A. M. Pens, Jr., E. M. Leboute, and J. Corteline, 1992. A nutritional evaluation of a high fiber sunflower meal. J. Appl. Poult. Res. 1: 382-388. Waldroup, P. W., C. M. Millard, and R. J. Mitchell, 1970. Sunflower meal as a protein supplement for broiler diets. Feedstuffs 42(43):41. Zatari, I. M., and J. L. Sell, 1990. Sunflower meal as a component of fat-supplemented diets for broiler chickens. Poultry Sci. 69:1503-1507. World Oilseed Situation and Outlook, 1992. United States Department of Agriculture, Washington, DC. June issue.
method for the production of SFM is prepress solvent-extraction of sunflower The worldwide production of sun- seeds. Because the processing involves flower meal (SFM) is large. In 1990, it was heating, it is possible that SFM could be estimated that world production of SFM overcooked. It has been shown that excess was 8.6 million metric tons, which ranked heating of soybean meal and canola meal fourth in oilseed production behind soy- decreases in vivo availability of some bean meal, cottonseed meal, and canola amino acids, particularly Lys (Hancock et meal, respectively (World Oilseed Situa- al, 1990; Parsons et al, 1992; Andersontion and Outlook, 1992). Thus, SFM is Hafermann et al, 1993). Thus, overprocessoften used in poultry rations. As reviewed ing of SFM could greatly affect its nutriby Zatari and Sell (1990) and Vieira et al. tional value because sunflower protein is (1992), high levels of SFM can be used very deficient in Lys. Indeed, Rad and successfully in broiler chicken and laying Keshavarz (1976) reported that the chemihen diets if adequate levels of dietary Lys cally determined available Lys content of and metabolizable energy are provided. SFM decreased when the processing temThe most common commercial processing perature was increased. Protein solubility in KOH has been reported to be a good indicator of reduced protein quality in overprocessed soybean Received for publication June 21, 1993. meal (Araba and Dale, 1990; Parsons et al, Accepted for publication October 4, 1993. 1991) and also was useful for detecting 1 To whom correspondence should be addressed at 284 Animal Sciences Laboratory, 1207 W. Gregory overprocessed canola meal (AndersonHafermann et al, 1993). However, its Drive, Urbana, IL 61801. INTRODUCTION
436
HEATING EFFECTS ON SUNFLOWER MEAL QUALITY
usefulness as an indicator of protein quality for overprocessed SFM has not been evaluated. The objectives of the present study were to determine the effect of overprocessing on in vivo protein quality of SFM and the usefulness of protein solubility in KOH as indicator of reduced in vivo protein quality due to overprocessing of SFM. MATERIALS AND METHODS Sunflower meal used in all experiments in this study was obtained as a single batch from a commercial solvent extraction processing plant. 2 To ensure that overprocessing of the SFM occurred, a thin layer (1.25 cm in depth) was placed on metal trays, covered tightly with aluminum foil, and autoclaved at 121 C and 105 kPa for increasing amounts of time from 0 to 90 min. Protein solubility of the processed SFM in .2% KOH was determined by the method described by Parsons et ah (1991). Amino acid concentrations in the SFM and excreta from the digestibility trials described below were determined in duplicate or triplicate using ion-exchange chromatography 3 following hydrolysis in 6 N HC1 for 22 h at 110 C (Spackman et ah, 1958). Analyses of Met and Cys were conducted separately following performic acid oxidation by the method of Moore (1963) except that samples were diluted with water and lyophilized to remove excess performic acid following the 16-h oxidation period. Crude protein levels were determined by the macroKjeldahl method (Association of Official Analytical Chemists, 1980). Experiments 1 and 2 were conducted to evaluate the effects of overprocessing on in vivo protein quality of SFM for chicks and to evaluate the KOH assay as an indicator of overprocessing. Male chicks, obtained by crossing New Hampshire males and Columbian Plymouth Rock females, were housed in thermostatically controlled starter batteries with raised
2
NationaI Sun Co., Enderlin, ND 58027. Beckman Model 6300 amino acid analyzer, Beckman Instruments Corp., Palo Alto, CA 93402. 3
437
wire floors and provided with water and feed for ad libitum consumption. Uniform light was provided 24 h / d . The chicks were fed a 24% CP corn-soybean meal diet during the first 7 d posthatching. After being deprived of feed overnight, chicks were weighed, wing-banded, and assigned to dietary treatments by the procedure of Sasse and Baker (1974). In Experiment 1, corn-SFM diets containing 22% CP (Table 1) were prepared from SFM autoclaved for 0, 30, 60, or 90 min. For comparison, a commercial cornsoybean meal diet containing 23% CP was also evaluated. In Experiment 2, corn-SFM diets were prepared from SFM autoclaved for 0, 10, 20, 30, 40, or 60 min. The cornSFM diets were formulated to be slightly deficient in Lys and SAA to increase sensitivity for detecting adverse effects of overprocessing on protein quality of SFM. Each of the diets in both experiments was fed to three replicate groups of six male chicks from 8 to 17 d posthatching. Body weight and feed intake of each replicate group were measured at the termination of the experiments, and weight gain and feed efficiency (gain:feed ratio) were calculated. Experiment 3 was conducted to determine the true digestibilities of amino acids in SFM autoclaved for 0, 30, 60, or 90 min. The precision-fed cockerel assay of Sibbald (1986), with some modifications, was used for determining the digestibility values. At 25 wk of age, Single Comb White Leghorn cockerels were cecectomized as previously described (Parsons, 1985) and were not used in digestibility trials for at least 8 wk following surgery. The birds were housed in individual cages with raised wire floors in an environmentally regulated room having a 16 h light:8 h dark photoperiod. Feed and water were provided for ad libitum consumption except when the birds were being used in a digestibility assay. Following 24 h of feed deprivation, five cockerels were given 30 g of a SFM sample via crop intubation. To estimate endogenous amino acid excretion, the same number of cockerels were deprived of feed for the duration of the digestibility assay. Excreta were quantitatively collected on plastic trays placed under each cage for 48 h. The excreta were frozen,
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ZHANG AND PARSONS
lyophilized, weighed, ground to pass through a 60-mesh screen, and analyzed for amino acid content as described previously. True digestibility of amino acids was calculated by the method of Sibbald (1979), with digestibility referring to the amount of dietary amino acid not appearing in the feces plus urine. The chick performance data, amino acid digestibility values, and KOH protein solubility values obtained in the experiments were analyzed by ANOVA for completely randomized designs (Steel and Torrie, 1980) using algorithms generated by the SAS Institute (1982). Differences between treatment means were assessed using the least significant difference test and single degree-of-freedom contrasts where meaningful (Steel and Torrie, 1980). Regression analysis was also used to evaluate the chick performance response
to autoclaving of SFM (Steel and Torrie, 1980). RESULTS The effects of autoclaving time on chick performance and protein solubility observed in Experiment 1 are shown in Table 2. Increasing autoclaving time resulted in a linear decrease (P < .05) in weight gain and feed efficiency, and a quadratic decrease in protein solubility. In comparison to the unautoclaved SFM, autoclaving for 30 min or more significantly reduced (P < .05) weight gain and protein solubility. Protein solubility decreased as SFM was autoclaved for 30 and 60 min, but no further reduction in protein solubility was observed when autoclaved for 90 min. Compared with the unautoclaved SFM, the reductions at 90 min were 23, 16, and
TABLE 1. Composition of the corn-sunflower meal basal diet and the corn-soybean meal diet Ingredients and analysis
Corn-sunflower meal basal diet
Corn-soybean meal diet -
Sunflower meal (36% CP) Soybean meal (48.5% CP) Alfalfa meal (17% CP) Menhaden fish meal (60% CP) Corn (7.65% CP) Corn oil Dicalcium phosphate Ground limestone Choline-Cl (60%) Iodized salt DL-methionine L-LysHCl Vitamin premix1 Trace mineral premix2 Calculated analysis3 CP MEn/ kcal/kg Methionine + cystine Lys Ca Available P
\/U)
52.90
33.085 10.00 1.35 1.50 .10 .40 .16 .33 .10 .075 22 3,008 .88 1.10 1.00 .45
37.00 1.00 2.00 51.925 4.00 2.20 1.00 .10 .40 .20 .10 .075 23.3 3,064 .91 1.41 1.07 .59
Provided per kilogram of diet: vitamin A (as vitamin A acetate), 4,400 IU; cholecalciferol (as activated animal sterol), 1,000 IU; vitamin E (as a-tocopheryl acetate), 11 IU; vitamin B12, .01 mg; riboflavin, 4.41 mg; dpantothenic acid, 10 mg; niacin, 22 mg; menadione sodium bisulfite, 2.33 mg. 2 Provided as milligrams per kilogram of diet: manganese, 75 from manganese oxide; iron, 75 from iron sulfate; zinc, 75 from zinc oxide; copper, 5 from copper sulfate; iodine, .35 from ethylene diamine dihydroiodide; selenium, .2 from sodium selenite. 3 Values for CP and amino acids are based on analytical values for corn, sunflower meal, and soybean meal and all other ingredient values are based on ingredient table values from the NRC (1984). The latter values for sunflower meal were the average of the values for solvent-extracted sunflower meal with and without hulls in the NRC (1984) table.
HEATING EFFECTS ON SUNFLOWER MEAL QUALITY
439
TABLE 2. Effect of autoclaving sunflower meal on chick performance and protein solubility, Experiment 1
Diet Corn-sunflower, 22% CP
Autoclaving time
Weight gain 1 ' 2
Gain:feed ratio1-2
(min) 0 30 60 90
(g)
teg)
127b 115= 108d 98 e 146= 2.0
.619** .577*>c .546cd .521 d .655= .017
Corn-soybean meal, 23% CP Pooled SEM
Protein solubility in .2% KOH 1 . 2
(%) 64 b 58= 51 d 51d 84= .8
a_e
Means within a column with no common superscript differ significantly (P < .05). 1 Values for weight gain and gain:feed ratio are means of three replicate groups of six male chicks from 8 to 17 d of age; average initial weight was 72.7 g. Values for protein solubility are for the sunflower meal or soybean meal and are means of triplicate determinations. Significant linear effect of autoclaving (P < .001) for weight gain and gain:feed ratio and significant quadratic effect (P <: .005) for protein solubility.
20% for weight gain, feed efficiency, and protein solubility, respectively. Chicks fed the corn-soybean meal diet performed better (P < .05) than chicks fed any of the corn-SFM diets. Experiment 2 was conducted to determine the effect of autoclaving times intermediate to those used in Experiment 1. Autoclaving SFM for 10, 20, or 30 min reduced chick performance (P < .05) to a similar extent (Table 3). There was a further decrease (P < .05) in chick perfor-
mance when SFM was autoclaved for 40 min, but no further reduction occurred at 60 min of autoclaving. The magnitude of these performance decreases due to autoclaving were comparable to those obtained in Experiment 1. Protein solubility in .2% KOH decreased linearly from 0 to 30 min of autoclaving. A further reduction in protein solubility was observed at 60 min of autoclaving. The effect of autoclaving time on total amino acid concentrations in SFM is
TABLE 3. Effect of autoclaving sunflower meal on chick performance and protein solubility. Experiment 2 Autoclaving time
Weight gain1-2-3
Gain:feed ratio1-2'3
Protein solubility1'2-4
(min)
(g)
(g:g)
0 10 20 30 40 60 Pooled SEM
131= 120bc 123 ab 12ibc H 2 cd 110d 3.3
.636"
(%) 65= 62b 59= 56d 55d 51*
a_
.608b .605bc .604>* .577cd .575d .009
«Means within a column with no common superscript differ significantly (P < .05). Values for weight gain and gain:feed ratio are means of three replicate groups of six male chicks from 8 to 17 d of age; average initial weight was 72.8 g. Values for protein solubility are means of triplicate determinations. 2 Linear effect of autoclaving (P < .01). 3 Single degree of freedom contrast of 10, 20, and 30 min vs 40 min was significant (P < .05). 4 Solubility of sunflower meal protein in .2% KOH. 1
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ZHANG AND PARSONS
TABLE 4. Effect of autoclaving on analyzed total amino acid concentrations in sunflower meal 1 Minutes autoclaved Amino acid
0
30
Aspartic acid Threonine Serine Glutamic acid Proline Glycine Cystine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Histidine Lysine Arginine
3.28 1.29 1.48 7.21 1.64 1.87 .56 1.87 .57 1.42 2.35 .76 1.61 .83 1.43 2.76
3.20 1.25 1.49 6.74 1.50 1.35 .55 1.67 .56 1.40 2.14 .73 1.52 .75 1.04 2.61
60
90
3.01 1.23 1.35 6.40 1.40 1.26 .54 1.58 .54 1.37 2.03 .72 1.48 .71 .89 2.48
3.00 1.25 1.36 6.50 1.47 1.22 .50 1.62 .52 1.36 2.05 .64 1.45 .71 .84 2.40
(%)
1 91.5% DM basis. Amino analyses performed in triplicate; mean coefficient of variation for amino acid analyses within samples was 3.8%.
shown in Table 4. Ninety minutes of autoclaving reduced the Lys concentration by 41% below that obtained for the unautoclaved meal (P < .05). Autoclaving had much less effect on the concentration of the other amino acids. The average reductions for these other amino acids when autoclaved for 30, 60, or 90 min were 7, 12, and 12%, respectively, compared with 27, 38, and 41% for Lys, respectively. As shown in Table 5, the true digestibility of Lys, expressed as a proportion of the
analyzed Lys in the unautoclaved SFM, decreased markedly (P < .05) for each 30-min increase in autoclaving time (Experiment 3). The largest decrease occurred for the first 30 min of autoclaving. The digestibility of the analyzed Lys remaining after autoclaving was also significantly decreased as autoclaving time increased (P < .05). The effects of autoclaving on digestibility of other amino acids were less than those observed for Lys (Table 6). A significant decrease (P < .05) in digestibility was obtained only with valine at 30
TABLE 5. Effect of autoclaving on true digestibility of lysine in sunflower meal, Experiment 3 1
Autoclaving time (min) 0 30 60 90 Pooled SEM a_f
Digestibility as a proportion of analyzed Lys remaining after autoclaving
Digestibility as a proportion of analyzed Lys in unautoclaved sunflower meal
(%) 86^
86" 70b 67b 60c
54<*
43* 35f 2.1
Means with no common superscript differ significantly (P < .05). Values are means of five individual cecectomized cockerels.
HEATING EFFECTS ON SUNFLOWER MEAL QUALITY
441
TABLE 6. Effect of autoclaving on true digestibility of amino acids in sunflower meal, Experiment 3 1 Minutes autoclaved Amino acid
0
30
Threonine Cystine Valine Methionine Isoleucine Leucine Phenylalanine Histidine Arginine
87^ 81* 87= 85" 86* 87* 9ia 82* 93* 87
81*b 77ab 78 b 82*b 85* 82* 91* 76* 92* 83
60
90
80b 73b
76 b 71b 70c 78 b 76 b 68b 81b 66' 82c 74
, , Pooled SEM
(%)
X
73<:
79 b 78b 72b 84b 70bc
86b 77
1.8 2.6 1.0 1.5 1.4 1.4 1.0 2.2 .7
a_c
Means within a row with no common superscript differ significantly (P < .05). Values are means of five individual cecectomized cockerels expressed as a percentage of the amino acid content in the unautoclaved sunflower meal. 1
min of autoclaving whereas digestibility of all amino acids listed in Table 6 was decreased at 60 min of autoclaving. However, only arginine digestibility was reduced further (P < .05) at 90 min of autoclaving. DISCUSSION The present study showed that overprocessing by autoclaving reduced in vivo protein quality of SFM. Overprocessing decreased both growth performance of chicks and digestibility of amino acids in adult cockerels. That the effects of overheating were greater for Lys than other amino acids is in agreement with recent studies on soybean meal by Parsons et al. (1992) and for canola meal by AndersonHafermann et al. (1993). The large decrease in Lys digestibility can probably be attributed largely to Maillard reaction products formed during autoclaving (Hurrell, 1990). The reduction in Lys digestibility when expressed both as a proportion of the analyzed Lys in the unautoclaved SFM and as a proportion of the analyzed Lys remaining after autoclaving indicates that a wide range of Maillard reaction products may have been produced. The large decreases in analyzed Lys by autoclaving indicated Lys destruction due to formation of advanced Maillard reaction
products. The reduced digestibility of the analyzed Lys remaining after autoclaving indicated formation of early Maillard reaction products, which are recoverable during amino acid analysis (acid hydrolysis) but are not available for in vivo protein synthesis (Hurrell, 1990). The reduction in chick growth performance due to autoclaving SFM (Table 2) was somewhat less than expected based on the decrease in Lys digestibility due to autoclaving. The amount of digestible Lys in the corn-SFM diet decreased by .38% as the SFM was autoclaved for 90 min. Based on the results of Han and Baker (1991), the growth depression from a .38% decrease in dietary digestible Lys should have exceeded that observed herein. These observations suggest that the digestibility assay may have underestimated the amount of SFM Lys that was available to the chicks. The results herein clearly showed that protein solubility in KOH decreased as SFM was overcooked. Similar results have been reported for soybean meal (Araba and Dale, 1990; Parsons et al, 1991) and for canola meal (Anderson-Hafermann et al., 1993). These results indicated that, as for soybean meal and canola meal, protein solubility in KOH is a useful index of overprocessing of SFM and protein solubility values of approximately 60% or
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ZHANG AND PARSONS
lower are indicative of overprocessed SFM. Similar to observations for canola meal (Anderson-Hafermann et ah, 1993), the KOH assay for detecting overprocessing of SFM is probably not as sensitive as previously reported for soybean meal (Araba and Dale, 1990; Parsons et al, 1991). The reductions in protein solubility of soybean meal due to overheating in the latter studies were much greater than those observed herein for SFM. The reduced performance of chicks fed the com-SFM diet compared with the corn-soybean meal diet herein was probably and partially due to marginal deficiencies of protein, Lys, and SAA. Other factors may also have been involved, however, because previous studies have reported depressed performance of chicks fed diets high in SFM. Dietary levels of 15 to 20% SFM are well tolerated by broiler chickens, whereas higher levels often result in reduced growth performance (Waldroup et al, 1970; Rad and Keshavarz, 1976; Zatari and Sell, 1990). The level of 52.5% SFM used in the broiler diets herein greatly exceeded the levels found to be tolerable in the earlier broiler studies. In contrast, Vieira et al. (1992) recently found that laying hens could tolerate levels of SFM up to at least 40% of the diet.
REFERENCES Anderson-Hafermann, J. C , Y. Zhang, and C. M. Parsons, 1993. Effects of processing on the nutritional quality of canola meal. Poultry Sci. 72:326-333. Araba, M , and N. M. Dale, 1990. Evaluation of protein solubility as an indicator of overprocessing soybean meal. Poultry Sci. 69:76-83. Association of Official Analytical Chemists, 1980. Official Methods of Analysis. 13th ed. Association of Official Analytical Chemists, Washington, DC. Han, Y., and D. H. Baker, 1991. Lysine requirement of fast- and slow-growing broiler chicks. Poultry Sci. 70:2108-2114. Hancock, J. D., E. R. Peo, Jr., A. J. Lewis, and J. D. Crenshaw, 1990. Effects of ethanol extraction and duration of heat treatment of soybean flakes on the utilization of soybean protein by growing rats and pigs. J. Anim. Sci. 68:3233-3243.
Hurrell, R. F., 1990. Influence of the maillard reaction on the nutritional value of foods. Pages 245-258 in: The Maillard Reaction in Food Processing, Human Nutrition and Physiology. Birkhauser Verlag, Basel, Switzerland. Moore, S., 1963. On the determination of cystine as cysteic acid. J. Biol. Chem. 238:235-237. National Research Council, 1984. Nutrient Requirements of Poultry. 8th rev. ed. National Academy Press, Washington, DC. Parsons, C. M., 1985. Influence of cecectomy on digestibility of amino acids by roosters fed distillers dried grains with solubles. J. Agric. Sci. 104:469-472. Parsons, C. M., K. Hashimoto, K. J. Wedekind, and D. H. Baker, 1991. Soybean protein solubility in potassium hydroxide: an in vitro test of in vivo protein quality. J. Anim. Sci. 69:2918-2924. Parsons, C. M., K. Hashimoto, K. J. Wedekind, Y. Han, and D. H. Baker, 1992. Effect of overprocessing on availability of amino acids and energy in soybean meal. Poultry Sci. 71:133-140. Rad, F. H., and K. Keshavarz, 1976. Evaluation of the nutritional value of sunflower meal and the possibility of substitution of sunflower meal for soybean meal in poultry diets. Poultry Sci. 55: 1757-1765. SAS Institute, 1982. SAS® User's Guide: Statistics. Version 5 Edition. SAS Institute Inc., Cary, NC. Sasse, C. E., and D. H. Baker, 1974. Factors affecting sulfate-sulfur utilization by the young chick. Poultry Sci. 53:652-662. Sibbald, I. R., 1979. A bioassay for available amino acids and true metabolizable energy in feedstuffs. Poultry Sci. 58:668-673. Sibbald, I. R., 1986. The TME system of feed evaluation: methodology, feed composition data and bibliography. Technical Bulletin 1986-4E. Agriculture Canada, Ottawa, ON, Canada. Spackman, D. H., W. H. Stein, and S. Moore, 1958. Automatic recording apparatus for use in the chromatography of amino acids. Anal. Chem. 30:1190-1206. Steel, R.G.D., and J. H. Torrie, 1980. Principles and Procedures of Statistics. A Biometrical Approach. 2nd ed. McGraw-Hill Book Co., Inc., New York, NY. Vieira, S. L., A. M. Pens, Jr., E. M. Leboute, and J. Corteline, 1992. A nutritional evaluation of a high fiber sunflower meal. J. Appl. Poult. Res. 1: 382-388. Waldroup, P. W., C. M. Millard, and R. J. Mitchell, 1970. Sunflower meal as a protein supplement for broiler diets. Feedstuffs 42(43):41. Zatari, I. M., and J. L. Sell, 1990. Sunflower meal as a component of fat-supplemented diets for broiler chickens. Poultry Sci. 69:1503-1507. World Oilseed Situation and Outlook, 1992. United States Department of Agriculture, Washington, DC. June issue.