The effect of the extrusion process on the digestibility of feed given to laying hens

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1 Animal Feed Science and Technology 116 (2004) The effect of the extrusion process on the digestibility of feed given to laying hens M. Lichovnikova a,, L. Zeman b, S. Kracmar b, D. Klecker a a Department of Poultry Breeding, Mendel University of Agriculture and Forestry, MZLU v Brne, Zemedelska 1, Brno 61300, Czech Republic b Department of Animal Nutrition, Mendel University of Agriculture and Forestry, Zemedelska 1, Brno 61300, Czech Republic Received 17 September 2003; received in revised form 27 July 2004; accepted 29 July 2004 Abstract The purpose of the study was to observe the effect of feeding extruded feed that contained rapeseed (that was extruded using the standard methods for large-scale production of extruded feed) on retention and coefficient of total tract apparent digestibility (CTTAD) in hens. The laying hens were divided into two groups NEX and EXT. The composition of the diets was the same in both groups (wheat 39%, rapeseed 13.5%, pea 13.5%, soya bean meal 6%, maize 14%, fish meal 3%, limestone 1%, premix 10%). But 0.45 kg of 1 kg of the diets EXT (wheat, pea, and rapeseed) was extruded by dry extrusion at temperature 137 C and at moisture from 12 to 18% for 16 s. A balance assay was conducted with four laying hens from group NEX and eight from group EXT when they were 61 weeks old. The CTTAD of fat, calcium and amino-acids, and the retention of the nitrogen were estimated using the indicator method. The significance between the means was evaluated by a t-test. The average egg mass production during the assay was for group NEX 45 ± 3.9 g/hen/day and for group EXT 50 ± 5.0 g/hen/day. The extrusion process significantly increased (P < 0.001) the CTTAD of fat from (NEX) to (EXT). The coefficient of nitrogen retention was higher in group EXT (0.629) than in group NEX (0.584). The extrusion significantly increased the CTTAD of arginine (P < 0.05, NEX: 0.929, EXT: 0.944) and isoleucine (P < 0.05, NEX: 0.870, EXT: 0.904). The extrusion had a tendency to increase the CTTAD of leucine (P < 0.1, NEX: 0.885, EXT: 0.907), glutamic acid (P < 0.1, NEX: 0.931, EXT: 0.945), glycine (P < 0.06, NEX: 0.823, EXT: 0.859) and alanine (P < 0.1, NEX: 0.806, Abbreviations: CTTAD, coefficient of total tract apparent digestibility Corresponding author. Tel.: address: lichov@mendelu.cz (M. Lichovnikova) /$ see front matter 2004 Elsevier B.V. All rights reserved. doi: /j.anifeedsci

2 314 M. Lichovnikova et al. / Animal Feed Science and Technology 116 (2004) EXT: 0.844). CTTAD of lysine was almost the same in both groups (NEX: and EXT: 0.949). The extrusion process had a tendency to decrease the CTTAD of histidine (P < 0.06, NEX: 0.906, EXT: 0.859) and tyrosine (P < 0.07, NEX: 0.974, EXT: 0.921). The extrusion had a positive effect on the fat CTTAD, nitrogen retention and on the CTTAD of the essential amino-acids (except lysine and histidine). The decrease in the digestibility of these two amino-acids was not significant Elsevier B.V. All rights reserved. Keywords: Total tract apparent digestibility; Fat; Calcium; Amino-acids; Retention; Nitrogen 1. Introduction The nutrient profile of rapeseed makes it an ideal ingredient for high nutrient dense diets. Although content of goitrogens (glucosinolates) in rapeseed has been markedly reduced through genetic selection, at feeding higher levels of rapeseed the higher concentration of glucosinolates can occur in the diets. Extrusion is one of the methods to reduce the gucosinolate contents (Fenwick et al., 1986; Dänicke et al., 1998). Fenwick et al. (1986) used dry extrusion at temperature 150 and 130 C and Dänicke et al. (1998) used hydrothermal treatment at 105 C. Also Liang et al. (2002) reported about positive effect of extrusion on feeding value of rapeseed meal. However rapeseed meal has a little different quality than raw rapeseed because of its treatment after oil extraction. In general heating improves the digestibility of proteins by inactivating enzyme inhibitors and denaturing the protein that may expose new sites for enzyme attack (Camire et al., 1990). Extrusion also can affect the digestibility of starch. Bjorck et al. (in Camire et al., 1990) found that both the in vitro and in vivo digestibility of extruded starch was enhanced by extrusion. The purpose of the study was to find the effect of feeding extruded feed containing rapeseed that was extruded at operating conditions typical for large-scale production on retention and coefficient of total tract apparent digestibility (CTTAD). Extrusion was used to reduce glucosinolate content of rapeseed. Rapeseed was extruded together with wheat and pea because of technical fulfillment. 2. Material and methods The laying hens were divided into two groups: NEX and EXT. The composition of the mixtures NEX and EXT was the same (wheat 39%, rapeseed 13.5%, pea 13.5%, soya bean meal 6%, maize 14%, fish meal 3%, limestone 1%, premix 10%) but 45% of the mixture EXT was extruded. Wheat, pea and rapeseed in ratio 4:3:3 were mixed and grinded (screen 3 mm). Then part of the meal was extruded by dry extrusion at temperature 137 C and at moisture from 12 to 18% for 16 s. The extruder was made by Insta-Pro International the model Insta-Pro There was 45% of the extruded meal in the mixture EXT and 45% of the no extruded meal in the mixture NEX. The meals (extruded and no extruded) were mixed with the rest of components without next grinding. The composition and nutrient content of the mixtures are shown in Tables 1 and 2. Rapeseed with low content of glucosinolates (socalled double zeros 00 ) was used. The content of glucosinolates was in NEX 855 mol/kg

3 M. Lichovnikova et al. / Animal Feed Science and Technology 116 (2004) Table 1 Feed mixture formulation (g/kg) Group NEX EXT Wheat (extruded) 180 Rapeseed (extruded) 135 Pea (extruded) 135 Wheat (non-extruded) 180 Rapeseed (non-extruded) 135 Pea (non-extruded) 135 Wheat 210 Soya bean meal 60 Maize 140 Fish meal 30 Limestone 10 Premix 100 Composition of the premix: Ca, g/kg; P, 38.0 g/kg; Na, 7.9 g/kg; NaCl, 15.8 g/kg; Mg, 1.5 g/kg; K, 0.6 g/kg; S, 0.5 g/kg; Cu, 45.4 mg/kg; Fe, mg/kg; Zn, mg/kg; Mn, mg/kg; Co, 2.2 mg/kg; I, 32.5 mg/kg; Se, 4 mg/kg; Vitamin E, 231 mg/kg; Vitamin K3, 20.0 mg/kg; Vitamin B1, 20.6 mg/kg; Vitamin B2, 72.1 mg/kg; Vitamin B6, 30.0 mg/kg; Vitamin B12, 0.1 mg/kg; biotin, 1.0 mg/kg; niacin, mg/kg; folic acid, 9.6 mg/kg; calcium pantothenate, 89.9 mg/kg; cholin, 4672 mg/kg; l-lysine, 404 mg/kg; Met, 7104 mg/kg; Thr, 364 mg/kg; Vitamin A, 100,000 mj/kg; Vitamin D3, 20,000 mj/kg. and in EXT 765 mol/kg. At 61 weeks of age, four laying hens from group NEX and eight from group EXT were kept individually in balance cages. After a 1-week adjustment period, the balance assay was done. The hens were fed the mixture ad libitum. Excrement was collected every 24 h for 5 days and the samples were dried at 105 C each day to inhibit any changes. The CTTAD of the fat, calcium and amino-acids, and the retention of the nitrogen, ash and phosphorus were estimated using the indicator method. Insoluble ash in 3 mol l 1 Table 2 Diet composition (g/kg dry matter) Nutrient Dry matter (g) Crude protein (g) Methionine (g) 3.4 Sulphuric amino-acids (g) 6.6 Threonine (g) 6.2 Fibre (g) 35.9 AME a N (mj) 11.8 Ca (g) 37.4 P (g) 8.3 Na (g) 1.4 Mg (g) 1.6 Group (NEX + EXT) AME (kj/kg) = 38.5 (the content of fat in the mixture) CTTDA of fat + 17 (the content of crude protein in the mixture) (the retention of crude protein) + 17 (the content of nitrogen-free extract) a AME N in EXT = 12.3 mj/kg.

4 316 M. Lichovnikova et al. / Animal Feed Science and Technology 116 (2004) Table 3 Coefficients of total tract apparent digestibility (CTTAD) and retention NEX (average ± S.E.) EXT (average ± S.E.) Significance CTTAD Dry matter ± ± NS Fat ± ± P < Calcium ± ± NS Retention of nutrients Nitrogen ± ± NS Ash ± ± NS Phosphorus ± ± NS S.E., standard error; NS, non-significant. HCl was used as an indicator. The content of nitrogen was determined according to Kjeldahl. The content of fat was determined according to Soxhlet. Ash was determined after searing at 550 C. The contents of calcium and phosphorus were determined by spectrophotometry. The samples of the feed and excrement were treated by oxidative acid hydrolysis HCl (c = 6 mol l 1 ). The samples to measure sulphur amino-acids were hydrolysed separately and before oxidative acid hydrolysis they were oxidised by performic acid. The chromatographic analysis of the hydrolysate samples was performed in the analyser AAA 400 (f. Ingos, Prague) using Na-citrate buffers and ninhydrin detection to find the amounts of certain amino-acids. The significance between the means was evaluated by a t-test (Snedecor and Cochran, 1967). 3. Results and discussion The effect of the extrusion process on the performance of the laying hens when it is 45% of the feed, and the quality of their eggs has been already published (Lichovnikova et al., 2000). The average weight of the hens was 1775 g (NEX) and 1791 g (EXT) at the start of the assay. The average egg mass production during the assay was for group NEX 45 ± 3.9 g/hen/day and for group EXT 50 ± 5.0 g/hen/day. The difference was not significant. The average feed intake in group NEX was 89.3 ± 3.74 g/hen/day and in group EXT it was 88.6 ± 2.06 g/hen/day. The CTTAD and the retention of nutrients are shown in Table 3. The CTTAD of dry matter was no significantly enhanced by extrusion (NEX: 0.789, EXT: 0.813). Extrusion significantly (P < 0.001) increased the CTTAD of fat from (NEX) to (EXT). Extrusion did not affect the CTTAD of the calcium (NEX: and EXT: 0.674). Retention of nitrogen was no significantly higher in group EXT (0.629) than in the group NEX (0.584). Retention of ash was also slightly no significantly higher in group EXT (0.612) than in group NEX (0.591). The retention of phosphorus was no significantly higher in group NEX in comparison with that of group EXT (0.520 vs ). The coefficients of CTTAD of the amino-acids are shown in Table 4. Generally, the extrusion process had a positive effect on the CTTAD of the amino-acids. The extrusion significantly increased the CTTAD of arginine (P < 0.05, NEX: 0.929, EXT: 0.944) and isoleucine (P < 0.05, NEX: 0.870, EXT: 0.904). The extrusion had a tendency to increase

5 M. Lichovnikova et al. / Animal Feed Science and Technology 116 (2004) Table 4 Coefficients of total tract apparent amino-acid digestibility NEX (average ± S.E.) EXT (average ± S.E.) Significance Lysine ± ± NS Methionine ± ± NS Threonine ± ± NS Arginine ± ± P < 0.05 Histidine ± ± P < 0.06 Isoleucine ± ± P < 0.05 Leucine ± ± P < 0.1 Valine ± ± NS Phenylalanine ± ± NS Tyrosine ± ± P < 0.07 Cysteine ± ± NS Aspartic acid ± ± NS Serine ± ± NS Glutamic acid ± ± P < 0.1 Proline ± ± NS Glycine ± ± P < 0.06 Alanine ± ± P < 0.1 S.E., standard error; NS, non-significant. the CTTAD of leucine (P < 0.1, NEX: 0.885, EXT: 0.907), glutamic acid (P < 0.1, NEX: 0.931, EXT: 0.945), glycine (P < 0.06, NEX: 0.823, EXT: 0.859) and alanine (P < 0.1, NEX: 0.806, EXT: 0.844). CTTAD of lysine was almost the same in both groups (NEX: and EXT: 0.949). The extrusion process had a tendency to decrease the CTTAD of histidine (P < 0.06, NEX: 0.906, EXT: 0.859) and tyrosine (P < 0.07, NEX: 0.974, EXT: 0.921). The CTTAD of methionine, threonine, valine, phenylalanine, aspartic acid, serine and proline was no significantly higher after extrusion. The CTTAD of cysteine was no significantly lower after extrusion. Alonso et al. (2000) reported that extrusion of pea greatly elevated starch digestibility in vitro which can correspond with higher digestibility of dry matter in our experiment. Dänicke et al. (1998) found that increasing the temperature of the thermal treatments resulted in an increase in crude fat digestibility which coincides with our results. Also Mujahid et al. (2003) reported that extrusion significantly increased digestibility of fat of rice bran at broilers. Contrary to our findings Dänicke et al. (1998) reported a decrease in the digestibility of crude proteins after the treatments. On the other hand Alonso et al. (2000) reported that extrusion of pea greatly elevated protein digestibility in vitro. And also Dahlin and Lorenz (1993) observed beneficial effect of extrusion on protein digestibility of cerealgrain (including wheat) in vitro. Fernandezfigares et al. (1995) observed that after heat treatment (autoclaving), there was a significant increase in the digestibility of the aminoacids. Because methionine is the first limiting amino-acid followed by lysine the decrease of CTTAD of histidene is not relevant. Also Parsons et al. (1992) observed lower digestibility of histidine and cysteine after the heat treatment (autoclaving). They reported a lower digestibility of lysine that is contrary to our findings, but the content of lysine may have been impacted during the drying of the faeces in our experiment. Bioavailability of histidine was probably affected by Maillard reactions. Cysteine digestibility may also be affected by

6 318 M. Lichovnikova et al. / Animal Feed Science and Technology 116 (2004) the heat treatment during its conversion to lanthionine. As Opstvedt et al. (1984) found heating at 115 C caused a loss in cystine plus cysteine and reduced protein and amino-acid digestibility. 4. Conclusion Extrusion had a positive effect on the CTTAD of fat, the retention of nitrogen, and on the CTTAD of essential amino-acids except for lysine and histidine. But, the decrease of CTTAD of these two amino-acids was not significant. Acknowledgments Authors thank Mrs. Judy McPherson for the language correction.supported by the Ministry of Education, Youth and Sports of the Czech Republic (grant no. MSM ). References Alonso, R., Grant, G., Dewey, P., Marzo, F., Nutritional assessment in vitro and in vivo of raw and extruded peas (Pisum sativum L.). J. Agric. Food Chem. 48, Camire, M.E., Camire, A., Krumhar, K., Chemical and nutritional changes in foods during extrusion. Crit. Rev. Food Sci. Nutr. 29, Dahlin, K., Lorenz, K., Protein digestibility of extruded cereal-grains. Food Chem. 48, Dänicke, S., Kracht, W., Jeroch, H., Zachmann, R., Heidenreich, E., Lowe, R., Effect of different technical treatments of rapeseed on the feed value for broilers and laying hens. Anim. Nutr. 51, Fenwick, G.R., Spinks, E.A., Wilkinson, A.P., Heaney, R.K., Legoy, M.A., Effect of processing on the antinutrient content of rapeseed. J. Sci. Food Agric. 37, Fernandezfigares, I., Perez, L., Nieto, R., Aguilera, J.F., Prieto, C., The effect of heat-treatment on ileal amino-acid digestibility of growing broilers given vetch and bitter vetch meals. Anim. Sci. 60, Liang, M., Huang, S., Huff, H.E., Kerley, M.S., Hsieh, F., Extrusion cooking of rapeseed meal for feeding value improvement. Appl. Eng. Agric. 18, Lichovnikova, M., Klecker, D., Zeman, L., The effect of extruded rapeseed on laying performance and quality of eggs. Czech J. Anim. Sci. 45, Mujahid, A., Asif, M., Haq, I., Abdullah, M., Gilani, A.H., Nutrient digestibility of broiler feeds containing different levels of variously processed rice bran stored for different periods. Poultry Sci. 82, Opstvedt, J., Miller, R., Hardy, R.W., Spinelli, J., Heat-induced changes in sulfhydryl groups and disulfide bonds in fish protein and amino acid digestibility in rainbow trout (Salmo gairdneri). J. Agric. Food Chem. 32, Parsons, C.M., Hashimoto, K., Wedekind, K.J., Han, Y., Baker, D.H., Effect of overprocessing on availability of amino acids and energy in soybean meal. Poultry Sci. 71, Snedecor, G., Cochran, W., Statistical Methods. The Iowa State University Press.