Key words: Canola meal, B. juncea meal, composition, digestibility, pigs

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1 Nutritional composition and digestibility by 80-kg to 100-kg pigs of prepress solvent-extracted meals from low glucosinolate Brassica juncea, B. napus and B. rapa seed and of solvent-extracted soybean meal J. M. Bell 1, R. T. Tyler 2, and G. Rakow 3 1 Department of Animal and Poultry Science, University of Saskatchewan, 72 Campus Drive, Saskatoon, Saskatchewan, Canada S7N 5B5; 2 Department of Applied Microbiology and Food Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, Saskatchewan, Canada S7N 5A8; and 3 Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, Saskatchewan, Canada S7N 0X2. Received 10 October 1997, accepted 17 February Bell, J. M., Tyler, R. T. and Rakow, G Nutritional composition and digestibility by 80-kg to 100-kg pigs of prepress solvent-extracted meals from low glucosinolate Brassica juncea, B. napus and B. rapa seed and of solvent-extracted soybean meal. Can. J. Anim. Sci. 78: Seed of Brassica napus canola (cv. AC Excel), B. rapa canola (cv. AC Parkland), and B. juncea canola (line J ) was oil-extracted in a prepress solvent pilot plant. The three canola meals and soybean meal (SBM) (commercial) were fed in four replicates of a digestibility trial to evaluate their digestibility. The meals were mixed with a nutritionally adequate barley-wheat-sbm basal diet at levels of 15 and 30%. Chromic oxide (Cr 2 ) was included at 0.5% of the diet as a chemical marker. Eighteen hybrid gilts, approximately 90 kg, were randomized to the first two replicates involving nine diets, including the basal diet, and this allotment was repeated. Brassica juncea meal (air-dry) contained 43.85% crude protein of 82% digestibility and MJ kg 1 of gross energy of 71% digestibility. The corresponding values for B. napus AC Excel meal were 41.78, 81, and 64; for B. rapa AC Parkland meal 40.05, 79, and 71, and for SBM 45.10, 88, and 82. Digestible energy values were: B. juncea 13.9, B. napus 13.0, B. rapa 14.1 and SBM 15.9 MJ kg 1. Key words: Canola meal, B. juncea meal, composition, digestibility, pigs Bell, J. M., Tyler, R. T. et Rakow, G Composition nutritionnelle et digestibilité pour des porcs de 80 à 100 kg de tourteaux de pression-extraction obtenus à partir de graines de Brassica juncea, de B. napus et de B. rapa à basse teneur en glucosinolates en comparaison du tourteau de soja obtenu par extraction. Can. J. Anim. Sci. 78: Nous avons déshuilé dans un atelier pilote de pression-extraction les graines de Brassica napus, cv AC Excel, de B. rapa, cv AC Parkland et de B. juncea, lignée J , toutes trois de qualité canola. Les tourteaux résultants ainsi qu un tourteau de soja (TS) du commerce étaient ensuite évalués dans un essai de digestibilité à quatre répétitions. Les tourteaux étaient mélangés à raison de 15 et de 30 % à un aliment de base orge-blé-ts. L oxyde chromique (Cr 2 ) était incorporé dans l aliment à la dose de 0,5 % comme marqueur chimique. Dix-huit cochettes hybrides d environ 90 kg étaient réparties au hasard entre les deux premières répétitions, lesquelles comportaient neuf aliments, y compris le régime de base témoin. Cet allotement était répété deux semaines plus tard dans les deux répétitions restantes. Le tourteau de B. juncea, séché à l air ambiant, contenait 43,85 % de protéine brute, digestible à 82 % et 18,33 MJ kg 1 d énergie brute, digestible à 71 %. Les valeurs correspondantes étaient, pour le tourteau de B. napus cv Excel, 41,78 à 81 % et 18,64 à 64 %, pour celui de B. rapa cv AC Parkland, 40,05 à 79 % et 18,45 à 71 % et enfin pour le TS du commerce, 45,10 à 88 % et 17,28 à 82 %. Les valeurs d énergie digestible étaient, respectivement, de 13,9, 13,0, 14,1 et 15,9 MJ kg 1 pour B. juncea, B. napus, B. rapa et TS. Mots clés: Tourteau de qualité canola, tourteau de B. juncea, composition, digestibilité, porcs Adverse effects of allyl glucosinolates in Brassica juncea meal (oil-extracted) on bodyweight gain and thyroid histology were found in trials with mice and rats (Bell et al. 1971, 1972; Bille et al. 1983) and in pigs (Bell et al. 1981). Treatment of the meal with ammonia reduced the glucosinolate and sinapine contents (McGregor et al. 1983) and improved its feeding value for poultry (Blair 1984) and pigs (Keith and Bell 1985). More recently, the development of a low glucosinolate mustard by Love et al. (1990) gave promise of a canola-quality meal (CM) from low glucosinolate, low erucic acid B. juncea comparable to CM from B. napus or B. rapa. The equivalence of B. juncea meal in broiler chicken diets was demonstrated by Newkirk et al. (1997). 199 The objective of this study was to examine the composition and the digestibility by swine of meal derived from a recent experimental selection of B. juncea and to compare it with meal from common varieties of B. napus and B. rapa, all grown in the same year and location, and with commercial SBM. Abbreviations: ADF, acid detergent fiber; CM, canola meal(s); CP, crude protein; DE, digestible energy; GE, gross energy; NDF, neutral detergent fiber; SBM, soybean meal; TDF, total dietary fiber.

2 200 CANADIAN JOURNAL OF ANIMAL SCIENCE Table 1. Percentages of dietary gross energy, crude protein, ADF and NDF derived from meals incorporated at 15 and 30% of the diet Diet component derived from meal (%) Meal Weight, air-dry Energy CP ADF NDF AC Excel B. napus AC Parkland B. rapa J B. juncea Soybean meal MATERIALS AND METHODS Seed of AC Excel canola (B. napus), AC Parkland canola (Brassica rapa), and J canola (B. juncea) was produced on the Research Farm of Agriculture and Agri-Food Canada at Saskatoon in The seed was harvested at full maturity and cleaned to seed standards. Approximately 80 kg of seed of each type was extracted to produce oil and meal at the POS Pilot Plant Inc. (118 Veterinary Road, Saskatoon, SK, Canada S7N 2R4). The seed was first tempered to 8.5% moisture, flaked (0.30 to 0.40 mm), cooked over a period of 40 min reaching a maximum temperature of 97 C, passed through a preheated Simon-Rosedown prepress and solvent extracted using hexane for approximately 90 min. The marc (hexane-solids) was then desolventized in two stages. For about 25 min the marc was sparged with steam and reached 78 to 93 C. It was then transferred to the toasting tray where the temperature was 91 to 103 C and held for about 20 min, then hammermilled using a 5/64 in (approx. 2 mm) round-hole screen. One departure from the above procedure was recorded. The desolventizer temperatures applied to AC Excel CM were approximately 8 C lower than intended. Nitrogen solubility index values (American Oil Chemists Society 1989) were obtained on the meals and reported by the POS Pilot Plant Inc. The Brassica meals and SBM were each mixed at 15 and 30% levels for diets composed of a control or basal fraction and the test meal. The basal fraction contained ground barley 54, wheat 27, SBM 12.75, canola oil 2.5 and a vitaminmineral premix 3.75%. The premix was designed to ensure that all diets met or exceeded the nutrient requirements of pigs for the minerals Ca, P, Cu, Fe, Mn, Zn, Se and for the vitamins A, D, E, thiamin, riboflavin, niacin, pantothenic acid, choline, biotin and B 12 (Bell and Shires 1982). Each diet also contained 0.5% Cr 2, premixed with 0.5% canola oil, as a fecal marker. Procedures for chemical analysis of most feed and feces components reported here have been described (Bell and Keith 1991a) as have procedures for sample collection and preparation and for statistical analysis (Keith and Bell 1991). A Parr adiabatic calorimeter Model 1241 was used to determine gross energy. The Theander and Westerlund (1986) method was used to analyze for total dietary fiber Table 2. Chemical composition of B. napus, B. rapa, B. juncea and SBM used in digestibility trials Excel Parkland Component B. napus B. rapa B. juncea SBM Moisture (%) CP (N 6.25)(%) Ash (%) Ether extract (%) GE (kcal kg 1 ) (MJ kg 1 ) Nitrogen solubility index (%) Fiber (%) ADF NDF TDF % of protein fiber-bound Glucosinolates (µmol g 1 ) Allyl butenyl pentenyl OH-3-butenyl OH-3-pentenyl OH-benzyl 3-methylindolyl OH-3-methylindolyl Amino acids (% of the protein) Aspartic acid Threonine Serine Glutamic acid Proline Glycine Alanine Cystine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Histidine Lysine Arginine Tryptophan (TDF) and the protein found in the near-final step in the TDF assay was reported as percentage of sample protein that was fiber-bound. Digestibility coefficients were calculated using regression methods (Keith and Bell 1982). The diets were tested in digestion trials involving 18 gilts randomly allotted in two replicates and this procedure was repeated 2 wk later. This experiment involved two dietary levels of each of the four test meals plus the basal diet. These were fed to individually stalled pigs for 7 d, the last three of which were fecal collection days (Keith and Bell 1991). For a week prior to and following the feeding of the test diets the pigs were fed a standard diet similar to the basal diet but with CM replacing one-half of the SBM. The pigs were PIC hybrid gilts from the Prairie Swine Centre

3 BELL ET AL. CANOLA MEALS FOR PIGS 201 Table 3. Apparent digestibility of GE, CP, ADF and NDF in diets containing 15 and 30% of test meals; for these components in the basal diet and in diets fed in periods 1 and 2 of the digestion trials Meal in diet Apparent digestibility (%) Meal tested (%) GE SD z CP SD ADF SD NDF SD AC Excel B. napus AC Parkland B. rapa J B. juncea Soybean meal Basal diet (observed) Basal diet (regression) All diets Period Period z Standard deviation. (PSC Inc.), Saskatoon, derived from Pig Improvement (Canada) Ltd. stock. Average initial and final weights were 82 ± 7 and 95 ± 7 kg. Digestibility values for dry matter, crude protein (CP), gross energy (GE), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were calculated by regression methods (Keith and Bell 1982) from the diet digestibility coefficients for the three levels of each meal: 0, 15 and 30% for dry matter and corresponding percentages (Table 1) of the other constituent contributions to the diets by the test meals. RESULTS AND DISCUSSION Canola meals obtained from B. napus and B. rapa seed were similar in CP, ash, oil and GE contents (Table 2) but lower than the B. juncea meal in CP and ash. The small differences (<2%) in GE content was caused partly by the lower oil content (ether extract) in B. juncea meal but differences in the amounts and kinds of non-oil and non-protein constituents also may have been involved (Simbaya et al. 1995). The nitrogen solubility index was greater for the B. napus meal (AC Excel) which had been exposed to lower temperatures in the desolventizer-toaster phase of processing than was used for B. rapa or B. juncea meal (Table 2). Fiber, as measured by ADF, NDF and TDF, showed similar values for B. rapa and B. juncea, both of which were lower than B. napus, which is apparently higher in cellulose and lignin. Neutral detergent fiber in Brassica meals comprised 75 to 87% of the TDF compared with 47% in SBM, indicating relatively more cell wall contents and pectins in SBM fiber (Goering and Van Soest 1975). The fiber-bound (cell wall) protein (Table 2), assayed to estimate protein-free TDF, may be of low availability for the pig. These assays indicated that the Brassica meals had 24 to 28% of their protein bound to fiber whereas SBM had about 19%. The glucosinolate levels of the CM revealed a greater amount of indolyl types in B. napus meal than in B. rapa and B. juncea. Brassica juncea glucosinolates were mostly of the 3-butenyl type. Subsequent selections, from which a registered variety may arise, have been developed and contain much lower glucosinolate levels. The amino acid values (Table 2) were expressed as percentages of the protein in order to remove the effects of differences in CP and moisture percentages. While these values are appropriate for this study, more extensive, replicated studies are in progress for comparing cultivars and species. The present results, however, show lower values for methionine, lysine and tryptophan in B. juncea than in B. napus and B. rapa meals. All CM samples exceeded SBM in cystine and methionine and had lower values for isoleucine, leucine, lysine, arginine and tryptophan. The digestibility of GE and CP in the diets averaged about 80% (Table 3). Digestibility of SBM diets was greater than for Brassica diets and equaled or exceeded the values obtained for the basal diet. Digestibility of ADF showed greater variability than found with GE and CP but it is possible that ADF in B. rapa diets was more digestible than in B. napus and B. juncea diets. The lowest values for ADF digestibility were found in the basal diets. Digestibility of NDF was over 50% in most cases and showed little effect of level or source of NDF in the diet. It is also evident in Table 3 that there was good agreement between observed and regression-derived values for digestibility of components of the basal diet. It was also found that the digestibility values for period 2 were numerically greater (P > 0.05) than for period 1. Significant effects of pig weight on digestibility have been found with younger pigs and over a larger weight range than was involved in the present study (Roth and Kirchgessner 1984; Bell and Keith

4 202 CANADIAN JOURNAL OF ANIMAL SCIENCE Table 4. Average digestibility of diets containing three levels (0, 15, 30%) of either Excel or Parkland CM, J mustard meal or SBM, with coefficients of variability and probability values for linear, quadratic and level of meal effects Average digestibility Coefficient Probability for of diets of Linear Quadratic Level of Component Meal (%) variability effect effect meal effect Dry matter AC Excel < <0.01 B. napus AC Parkland B. rapa J < B. juncea SBM Gross energy Crude protein NDF ADF AC Excel < <0.01 AC Parkland < J < SBM AC Excel AC Parkland J SBM AC Excel < <0.01 AC Parkland J SBM AC Excel AC Parkland < <0.01 J SBM , 1991b). These findings indicate that the digestibility values obtained in the present experiment may exceed those appropriate for grower pigs because the pigs used in our experiment weighed about 90 kg. Tests for linear and quadratic effects of increasing levels of test meals yielded different results depending on the meal used and the diet component assayed (Table 4). For dry matter, the responses were linear in the case of the Brassica meals but with SBM the digestibility of its dry matter was similar to that of the basal diet, hence the lack of a relationship between meal level and digestibility. Similar linear and quadratic effects were observed with GE digestibility. Digestibility of dietary protein (Table 4) failed to show a linear response among levels of Brassica meals mainly because the digestibility of meal CP and basal CP was similar (Table 3). In contrast there was a linear response with SBM because its CP was more digestible than the basal CP. The different solubility indices (Table 2) associated with different processing temperatures for AC Excel and AC Parkland (32.9 and 17.0%, respectively) were not reflected in different CP digestibility (80.5 and 81.6%, respectively, Table 4). The relatively high content of fiber-bound CP in Brassica meals, compared with SBM (24 to 28 vs. 19% of the CP), was associated with lower digestibility of CP (79.4 to 80.7 vs. 82.5%, respectively) but it is evident that the fiber-bound CP in Brassica meals was partially digestible by pigs. The digestibility of NDF showed a linear response (P < 0.05) with AC Excel CM and B. juncea meal, with declining digestibility as the percentage of test meal in the diet increased (Tables 3 and 4). The NDF in AC Parkland CM was of similar digestibility to the basal NDF, so the response was not linear. The linear effect with SBM diets was borderline (P = 0.06). Differences among meals may be attributed in part to genetic differences in the chemical components of NDF but the relatively high coefficients of variability (Table 4), compared with those of GE or CP, probably also affected the linear responses. Variability in digestibility of ADF was greater than for NDF (Table 4) and significant linear effects were obtained only with AC Parkland CM which had greater digestibility of ADF than the other meals, including SBM (Table 3). As with NDF, genetic differences in the kinds and amounts of ADF components may have accounted for some of the meal species differences although the non-starch polysaccharides in meal derived from yellow and brown strains of canola were similar (Simbaya et al. 1995). Stringam et al. (1974) found that rapeseed with yellow seed color had 40% less hull than occurred in seed with brown seed coats. The hulls of yellow seed contain less crude fiber, NDF, ADF and

5 lignin than brown hulls and are significantly more digestible for pigs (Bell and Shires 1982). AC Parkland CM has partly yellow seed color and the J B. juncea seed was yellow, which was reflected in the lower fiber content of the meals. Estimates were made of the digestibility of CP in the test meals per se, derived from the regression relationship between the percentage of the total dietary CP supplied by the test meal and the digestibility (%) of CP in the diet at each of the three levels of test meal employed (0, 15 and 30%, air-dry basis, Table 2). Apparent digestibility of CP in the Brassica meals was similar to that of the basal diet CP, viz. AC Excel 81, AC Parkland 79, B. juncea 82 and basal 81%. The CP digestibility of SBM was 88%. The average digestibility of CP in Period 1 was 81 and of Period 2 was 83%, indicating a pig age or weight effect. Digestibility of GE, similarly estimated, resulted in values of 64% for AC Excel, 71 for AC Parkland, 71 for B. juncea and 82% for SBM. As occurred with CP, pig age or weight effects were evident; Period 1 was 70 and Period 2 was 74% for digestibility of GE. Estimates of the DE kg 1, dry matter basis, for these samples of meal were as follows: AC Excel 3120, AC Parkland 3375, B. juncea 3340 and SBM 3815 kcal, or 13.0, 14.1, 13.9 and 15.9 MJ, respectively. These values agree with those of the National Research Council (1988) for SBM at 3878 and for commercial CM at 3118 Kcal kg 1 dry matter basis. It is concluded that meal derived from B. juncea (line J ) was similar to that from AC Parkland CM in terms of DE and digestible protein content as determined using finisher pigs. ACKNOWLEDGMENTS Financial support was provided by the Saskatchewan Wheat Pool, Agricultural Research and Development, Downey Road, Saskatoon, SK, S7N 4L8, and a Food Safety Grant from Agriculture and Agri-Food Canada, Ottawa. Technical assistance in seed processing was provided by R. Kruger, POS Pilot Plant Corporation, 118 Veterinary Road, Saskatoon, SK, Canada S7N 2R4 and is gratefully acknowledged. Dawn Abbott and Luba Atamanenko gave valuable service in analyses and manuscript preparation, Sandra Hodgson in statistical aspects and David Dixon in the management of the pigs. This project was approved by the local Animal Care Committee. American Oil Chemists Society Official methods and recommended methods of AOCS 4th ed. Official method Ba D. Firestone, ed. Re-approved AOCS, Champaign, IL. Bell, J. M. and Keith, M. O Effects of barley hulls, dietary protein level and weight of pig on digestibility of canola meal fed to finishing pigs. Can. J. Anim. Sci. 68: Bell, J. M. and Keith, M. O. 1991a. A survey of variation in the chemical composition of commercial canola meal produced in Western Canadian crushing plants. Can. J. Anim. Sci. 71: Bell, J. M. and Keith, M. O. 1991b. Effect of pig weight and barley hulls on the digestibility of energy, protein and fibre in wheat, corn and hulless barley diets. Nutr. Res. 11: BELL ET AL. CANOLA MEALS FOR PIGS 203 Bell, J. M. and Shires, A Composition and digestibility by pigs of hull fractions from rapeseed cultivars with yellow or brown seed coats. Can. J. Anim. Sci. 62: Bell, J. M., Benjamin, B. R. and Giovannetti, P. M Histopathology of thyroids and livers of rats and mice fed diets containing Brassica glucosinolates. Can. J. Anim. Sci. 52: Bell, J. M., Shires, A., Blake, J. A., Campbell, S. and McGregor, D. I Effect of alkali treatment and amino acid supplementation on the nutritional value of yellow and Oriental mustard meal for swine. Can. J. Anim. Sci. 61: Bell, J. M., Youngs, C. G. and Downey, R. K A nutritional comparison of various rapeseed and mustard seed solvent-extracted meals of different glucosinolate composition. Can. J. Anim. Sci. 51: Bille, N., Eggum, B. O., Jacobsen, I., Olsen, O. and Sorensen, H Antinutritional and toxic effects in rats of individual glucosinolate (± myrosinase) added to a standard diet. 1. Effects on protein utilization and organ weights. Z. Tiephysiol. Tierenähr. Futtermittelkd. 49: Blair, R Nutritional evaluation of ammoniated mustard meal for chicks. Poult. Sci. 63: Goering H. K. and Van Soest, P. J Forage fibre analysis. Agric. Handbook No. 379, ARS, US Department of Agriculture, Washington, DC. Keith, M. O. and Bell, J. M Effects of ammoniation on the composition and nutritional quality of low glucosinolate rapeseed (canola) meal. Can. J. Anim. Sci. 62: Keith, M. O. and Bell, J. M Amino acid supplementation of ammoniated mustard meal for use in swine feeds. Can. J. Anim. Sci. 65: Keith, M. O. and Bell, J. M Composition and digestibility of canola press cake as a feedstuff for use in swine. Can. J. Anim. Sci. 71: Love, H. K., Rakow, G., Raney, J. P. and Downey, R. K Development of low glucosinolate mustard. Can. J. Plant Sci. 70: McGregor, D. I., Blake, J. A. and Pickard, M. D Detoxification of Brassica juncea with ammonia. Pages in Proc. 6th Int. Rapeseed Conf., Paris, France. National Research Council Nutrient requirements of swine. 9th Rev. ed., National Academy Press, Washington, DC. Newkirk, R. W., Classen, H. L. and Tyler, R. T Nutritional evaluation of low glucosinolate mustard meals (Brassica juncea) in broiler diets. Poult. Sci. 76: Roth, F. X. and Kirchgessner, M Digestibility of energy and crude nutrients in the pig in response to feeding level and live weight. Z. Tiephysiol. Tierenähr. Futtermittelkd. 51: Simbaya, J., Slominski, B. A., Rakow, G., Campbell, L. D., Downey, R. K. and Bell, J. M Quality characteristics of yellow-seeded Brassica seed meals: Protein, carbohydrates, and dietary fiber components. J. Agric. Food Chem. 43: Stringam, G. R., McGregor, D. I. and Pawlowski, S. H Chemical and morphological characteristics associated with seed coat color in rapeseed. Pages in Proc. 4th Int. Rapeseed Conf., Giessen, Germany. Theander, O. and Westerlund, E. A Studies on dietary fibre. Improved procedures for analysis of dietary fibre. J. Agric. Food Chem. 34: