Evaluation of undehydrated barley feed fractions and dried oat feed fractions from integrated starch-ethanol process in diets of growing pigs MattiNäsi and Erkki Aimonen Näsi, M. & Aimonen, E. 1992, Evaluation of undehydrated barley feed fractions and dried oat feed fractions from integrated starch-ethanol process in diets of growing pigs. Agric. Sei. Finl. 1: 291-301. (Univ. Helsinki, Dept. Anim. Sei., SF- -00710 HELSINKI, Finland.) The nutrient digestibility and protein utilization of undehydrated barley fractions: pro- tein (BP), protein fibre mixture (BPF) and distillers solids (DS) at two levels of inclu- sion in diets fortified to equal lysine content were assayed with growing pigs in a 6 x 6 Latin square. Dried barley fibre (BF), oat protein (OP) and oat fibre (OF) from inte- grated starch-ethanol production were evaluated as feed ingredients for pigs in three other trials. DS and OP had a higher essential amino acids content than BP, especially with respect to lysine. All fractions had a rather high ether extract content 46-196 g/kg and their fatty acid composition is presented. BP showed higher protein digestibility than DS (0.931 vs. 0.857) and pigs on BP-diet retained more N than on DS-diet. BF showed a low digestibility of OM and CP and 0.1 inclusion of BF mixed with BP depressed CP digestibility and N-retention. A higher protein supply from cereal pro- tein in the diet promoted N-retention but decreased protein utilization. OP had high digestibility and OFwas more digestible than BF. The study confirmed the high digest- ibility and energy values of the proteinous grain fractions and a high protein utilization when adequately fortified with lysine. The fibrous fractions have arather low nutrient digestibility and their use in pig diets is therefore limited. Key words: cereal protein, digestibility, protein utilization, nitrogen balance, pig feed- ing Introduction In Finland barley feed fractions from starch and distillery production employing an integrated pro- cess have been supplied as feedstuffs since 1987 with encouraging results and a positive response from the users. In this integrated process the majo- rity offeed ingredients are removed before alcohol manufacturing, avoiding most of the thermal treat- ments common in the traditionaldistillery process, thus yielding feed constituents of high nutritive value. Barley has been used as the main raw mater- ial in this process, although other cereals has been monitored too. Increased barley feed fraction supply for animal feeding is expected, if the pro- gress of fuel ethanol production schemes from cereals are realised. Dried barley protein and distillers solubles have been shown to have high digestibility and fortified with lysine, serve as good protein supplement in pig feeding (Näsi 1989, 1992, Alaviuhkola 1989). Altough most of the feed ingredients from 291 Agric. Sei. Fint. 1 (1992) https://www.c-info.fi/en/info/?token=oOsCuo5TjKRtpZjS.stgtvBQvBcSl7bUSJ44L7w.lCZDTwvH9i-VmKTe06zC4mOJEUBPObL8P5VV0sZd_ob-9qkCvEMAzvoYtoGXAZnNIrzt5DKJY0MKCFni6VcApiBYlDV9fTONf4Sfh8-9JXefQzflVMC8tctaKqoNofHvKSe5d2uZ1cwIG1xXnxfNzba_4_GHtdnReQmSma31MJxMhspa3UsjgLXETHgLCFpUUbjQe8L1blxR2-s2gZ7AYzaPcwBl2XJEklp8b-Vk4OTx7njwM2w1WsevftEcqE1qUnVQZFM2XemHeJ-3KzqmpS6oPH-RpcL4 the production plant have been delivered in the undehydrated form, no evaluation of the these wet feeds has been performed. The wet form is usually more economical within a reasonable transport dis- tance from the manufacture because drying costs are avoided and the possible detrimental thermal effects can be avoided. When there are soluble car- bohydrates and amino acids present, these can react during the drying prosess and form Maillard reaction products, which are largely unavailable, and have been shown to be present in distillery prod- ucts (Näsi 1985, 1989). Oats is the second most important crop in Finland and oats cultivation has been substituted for barley to a large extent, whileat the same time the surplus of oats has still increased. However since no previ- ous studies have been carried out in this area the suitability of oats in starch-ethanol process is unk- nown. Oat protein has a promising amino acid com- position, which makes it interesting to evaluate its value as a protein supplement in pig nutrition. Oat products have also aroused much attention among human nutritionists, since it has been demonstrated that oat bran provides a significant hypocholesterol- aemic effect (Chen and Andersen 1986). Cereal protein obtained after the starch and etha- nol process (Näsi 1988, 1989, 1992) has a rather low quality of protein considering the degree to which the composition of the absorbed amino acids is in accordance with that required by the pig. The amino acid composition of barley protein can be improved as a protein source for pig feeding by for- tification with pure amino acids, especially with lysine (Näsi 1989, 1992). The present paper reports the experiments which were conducted to determine and confirm the nutrit- ive value of undehydrated barley feed ingredients from starch-ethanol production and those of dried oat feed products and barley fibre for growing pigs. Material and methods Feed ingredients from barley and oats used in pig trials were obtained from the Alko Ltd Kosken- korva factory employing the ordinary integrated starch-ethanol process, except the barley protein and fibre mixture, which was manufactured without the separation of protein and fibre fractions in the production plant of Alko Ltd Rajamäki. The detailed description of the process employing the integrated starch-ethanol production method has been presented by Näsi (1988). The flow-chart of the process is shown inFigure 1. In the first experi- ment barley fractions of barley protein (BP), mixture (BPF) in the proportion of BP 0.9 and bar- ley fibre (BF) 0.1 and barley-starch distillers solids (DS) obtained after centrifugation of distillers solubles, were delivered undehydrated and preserv- ed with sodiumbenzoate, 2 g/kg. They were well preserved and had pH-values of 3.89, 3.93 and 4.56, respectively. Those lots were freeze-stored during the experimental period to ensure the stabil- ity. Barley fibre (BF) was dried, pelleted and sup- plemented prior to drying with 50 g/kg sugar beet molasses, corresponding to a proportion of 0.1 of molasses in the final product, to improve payabi- lity. The oat feed fractions were manufactured similarly as those from barley, but prior to the pro- cess oats was dehulled. Eleven dietary treatments were used in four sep- arate trials for nutritive value assays as outlined in Table 1. In the first experiment undehydrated bar- ley protein, barley protein and barley fibre mixture and distillers solids were included at two levels of supplement isonitrogenously in the barley based diets to supply 160 and 181 g of crude protein for- tified with pure lysine to 8.5 g/kg. The trial was designed as a 6 x 6 balancedLatin square with grow- ing pigs which were castrated males (Landrace x Large White) with an average initial weight of 31.9 (SE 3.86) kg and a final average weight of 96.7 (SE 4.19) kg. Two pigs outside the square were reserve animals and they were used for basic feed evalua- tion. As a succession dried barley fibre was assayed at two levels of inclusion in a change over trial (Exp. 2) following the first experiment with the same eight pigs at live weight from 98 to 114 kg. Oat protein as a protein supplement was evaluated at two levels of inclusion in the barley diet with four pigs at live weight from 63.4 to 88.4 kg (Exp. 292 Agric. Sei. Fint. 1 (1992) Fig, 1. The flow-chart of the intergrated starch-ethanol process and the stages at which the feed fractions are recovered. 293 Agric. Sei. Finl. 1 (1992) Agric. Sei. Fin!. 1(1992) 3). Oat fibre digestibility was measured as a sole diet component supplemented with minerals in four pigs at average live weight of 85 kg (Exp. 4). The pigs were kept during the whole experiment in metal metabolism cages equipped with col- lection trays allowing separate collection of faeces and urine. Each period comprised 5 days of adjust- ment and 5 days of total collection of faeces and urine. The pigs were fed twice daily according to a restricted feeding regime and their diets were ade- quately fortified with minerals and vitamins (Salo et al. 1982). The details of the procedure are the same as described by Näsi (1984). All animals completed the experiment successfully and the av- erage daily gain during the test was 857 g in first experiment. The feeds were analyzed by standard methods. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) were assayed according to Goering and Van Soest (1970). Amino acids and fatty acids were determined by high-performance liquid chromatography and gas chromatography in the research laboratory of Alko Ltd. The digestibilities of the ingredients were calcu- lated with a regression equation from the quantities of each feed consumed and the digestion coeffi- cients of the diets (Schneider and Flatt 1976) or by difference using separate data for basic feeds. Pig response to graded levels of the supplemental grain protein fractions was assessed in terms of ni- trogen (N) balance, urinary N and urea excretion, biological value and daily gain. The results were analyzed by the analysis of variance for a Latin Square. The sums of squares for treatment effect were further separated into single degrees of free- dom for comparisons of the dietary treatments: pro- tein sources and levels in diet (Snedecor and Cochran 1967). Table 1. The outline of the experimental design and diet composition. Experiment 1. DIET No 1 2 3 4 5 6 Protein supplement BP(1) BP (2) BPF(l) BPF (2) DS(1) DS (2) Barley g/kg 877 753 818 622 936 872 Protein supplement Barley protein, g/kg 124 247 - - - - Barley prot.+fibre, g/kg - - 189 378 Distillers solids, g/kg - - - - 64 128 Total protein sypply g/kg 160 181 160 181 160 181 Lysine supplement Crystalline lysine g/kg 3.68 3,01 3.43 2.48 3,01 1,66 Total lysine supply g/kg 8.5 8.5 8.5 8.5 8.5 8.5 Experiments 2,3 and 4. Exp. 2. Exp. 3. Exp. 4. DIET No 7 8 9 10 11 Grain fraction BF (1) BF (2) OP(l) OP (2) OF Barley g/kg 800 600 850 700 0 Protein supplement Barley fibre, g/kg 200 400 - Oat protein, g/kg - - 150 300 Oat fibre, g/kg - ... 1000 Lysine supplement Crystalline lysine g/kg 3.00 3.00 - - 294 295 Agric. Sei. Fint. 1 (1992) Results and discussion Composition of the grain fractions The chemical composition of the barley and oat feed fractions obtained from the integrated starch- ethanol process are presented in Table 2. The pro- ximate composition of the various ingredients cor- responds rather well with the previous datareferred to by Näsi (1988, 1989), which considered the feed originating from a pilot plant production. Starch was left in the proteinous fractions 300-400 g/kg DM, which is a little higher than in the earlier ana- lysis (Näsi 1988). fl-glucan contents of the ingre- dients were 27, 19 and 9 g/kg in BP, in BF and in DS, respectively. A much higher value, 118 g/kg DM, was found in OF, which was obtained without using any supplemental enzyme during the process (Unpublished.). Oats have been reported to contain a high proportion of soluble fibre mainly as B-glu- cans (Frölich and Nyman 1988, Aspinall and Carpenter 1984). Bach Knudsen and Hansen (1991) found an oat bran product to compose much. 98 g/kg B-glucans, rather similar to the present OF product. The amino acid composition of BP and BF was inferior compared to those of fractions received from oats revealing the protein quality of the grain raw material. Oat protein concentrates produced by a wet-milling process have been previously shown to contain lysine 39-41 g/kg protein and total sul- phur amino acids 33-43 g/kg CP (WU et al. 1973). Considerably lower values were found in oat pro- tein concentrate obtained by alkali extraction, lysine 34 g and sulphur-amino acids of 34 g/kg CP (Delisle et al. 1991). Distillers solids also had a richer essential amino acid content than other bar- ley fractions in this study. This may be explained by the changes in the process used at the moment, in which barley solubles is not separated but it is directed in mashing. Näsi (1988, 1989) found a higher lysine content in barley molasses than in BP. Table 2. The chemical composition of the experimental feeds. Feedstuff Barley Barley Distillers Barley Oat Oat Composition protein protein solids fibre protein fibre +fibre Dry matter, g/kg 231 237 151 878 967 887 Ash, g/kg DM 39 46 48 39 20 42 Grade protein “ 312 248 470 200 408 237 Ether extract “ 46 56 134 75 196 105 Grade fibre" 14 48 26 140 9 46 Starch" 402 328 83 118 297 328 Total sugars" 75 75 31 66 13 30 Neutral detergent fibre 180 515 14 304 Acid detergent fibre 47 154 46 Amino acids, g/160 g N Lysine 30 36 47 43 43 64 Threonine 36 38 48 41 33 38 Methionine 23 24 25 22 19 20 Cystine 38 41 29 33 24 25 Histidine 19 20 24 7 28 26 Leucine 70 67 74 71 94 87 Isoleucine 41 38 46 43 55 49 Phenylalanine 57 52 53 52 72 60 Arginine 43 43 43 57 84 85 Serine 43 45 53 47 63 66 Valine 52 52 58 57 65 66 Aghc. Sei. Finl. 1 (1992) The dried distillers solubles had decreased lysine and other essential amino acids compared to BP (Näsi 1988, 1989) or to the present DS product without drying indicating some detrimental effects in the drying process. All the grain feed fractions had a rather high ether extract content, 46-196 g/kgDM, and this has an augmenting effect on energy content of these feeds. However the high content of unsaturated fatty acids of the lipids may also have some effects on pig carcase quality (Näsi 1989) and rumen digestive function (Huhtanen 1991). There is no previous data concerning the fatty acid profile of feed fractions from the integrated starch-ethanol process. The fatty acid composition of the present ingredients is presented in Table 3. The relations of different fatty acids revealed well thatof the lipids in the grain raw material used. Distillers solids showed a lower ether extract content than the total fatty acid sum, which is difficult to explain, but may be attributed to the different hydrolysis methods used prior to the analysis offatty acids and ether extract. A high fat content in oat protein con- centrate, 101-177 g/kg, has also been reported by WU et al. (1973). Digestibility and feed values The digestibilities of the different diets are present- ed in Table 4. All the barley feed fractions seemed to be palatable to the pigs even at the higher levels of inclusion. Oat fibre was an exception, and the daily allowance had to be reduced after a prelimi- nary period. Various amounts of ingredients were incorporated in the diets which make the compari- son of diets' digestibility rather complicated. Diet protein level had an improving effect on protein digestibility (P<0.05). Nutrient digestibilities, obtained for barley assayed as sole diet supplement- ed with minerals or calculated by regression from diet digestibilities fed at two levels, were close to each other: OM 0.846 vs 0.846 (SD 0.0022); CP 0.794 vs 0.799 (SD 0.0082); EE 0.485 vs. 0.437 (SD 0.0239); CF 0.207 vs 0.262 (SD 0.038) and NFE 0.913 vs 0.911 (SD 0.0027). The digestibilities and calculated feed values of Table 3. The fatty acid composition of the experimental feeds. Feedstuff Barley Barley Distillers Oat Oat protein fibre solids protein fibre Fatty acid, g/kg DM Hexanoic C6O 0.011 0.010 0.0 0.081 0.013 Heptanoic C7O 0.002 0.002 _ 0.0 0.0 0.002 Octanoic Cg 0 0.002 0.002 0.03 0.026 0.004 Nonanoic C 9 0 0.002 0.003 0.0 0.022 0.003 Decanoic Clo 0 0,002 0.002 0.11 0.0 0.003 Undecanoic CllO 0.001 0.001 0.0 0.037 0.001 Dodecanoic Cl 2 0.002 0.002 0.16 0.151 0,001 Tetradecanoic Cl4O 0.144 0.217 0.61 0.267 0.126 Hexadecanoic Cl 6 6.981 12.462 47.06 17.468 9.657 Octadecanoic Clg 0 0.606 0.904 3.31 1.706 0.908 Eicosanoic C2OO 0.010 0.882 0,12 0.068 0.053 9Octadecanoic C,,., 4.186 10.771 20.53 35.071 27.994 9 l2 Octadecadienoic C |g2 18.926 40.286 79.82 39.285 27.322 9,2ls Octadecatrienoic Clg3 0.0 0.0 8.29 0.0 0.0 Total 30.877 65.544 160.04 94.182 66,087 Ether extract 50 85 130 155 126 Fatty acids/ether extract 0.618 0.771 1.229 0.608 0.525 296 Table 4. The digestibilities of the experimental diets. Experiment 1. DIET No 1 2 3 4 5 6 SEM Significant effect of Prot.supplement BP(1) BP (2) BPF(l) BPF(2) DS(1) DS (2) Prot. source Prof level Digestibility Organic matter 0.860 0.869 0.843 0.841 0.843 0.850 0.0032 *** * Ash 0.497 0.519 0.467 0.485 0.481 0.523 0.0112 NS ** Crude protein 0.836 0.853 0.817 0.835 0.793 0.804 0.0057 *** * Ether extract 0.562 0.611 0.531 0.571 0.547 0.610 0.0096 NS *** Crude fibre 0.228 0.227 0.210 0.234 0.259 0.309 0.0166 ** NS NEE 0.918 0.922 0.907 0.901 0.907 0.913 0.0020 *** * Exreriments 2, 3 and 4. Exp. 2. Exp. 3 Exp. 4. DIET No 7 8 SEM Signific. 9 10 SEM Signific. 11 Grain fraction BF(1) BE (2) of differ. OP(l) OP (2) of differ. OF Digestibility Organic matter 0.792 0.740 0.0036 0.866 0.883 0.0077 NS 0.813 Ash 0.384 0.359 0.0107 NS 0.441 0.484 0.0310 NS 0.276 Crude protein 0.796 0.774 0.0065 NS (o) 0.841 0.877 0.0090 NS 0.810 Ether extract 0.505 0.505 0.0140 NS 0.747 0.835 0.0070 * 0.422 Crude fibre 0.225 0.201 0.0156 NS 0.231 0.221 0.0539 NS 0,269 NFE 0.864 0.820 0.0020 **� 0.923 0.932 0.0045 NS 0.929 NS (non-significant), * P<0.05, *• P