JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND 685 Maataloustieteellinen A ikakauskirja Vol. 60: 685—699, 1988 The effect of enzyme treatment of cooked barley and supplementation of piglet diets on the digestibility of barley and piglet performance J. INBORR M. NÄSI 2 and K. SUOMI’ 1 Finnish Sugar Co. Ltd., Finnfeeds Ltd., Forum House, Brighton Road, Redhill, Surrey RHI 6YS, England University of Helsinki, Department of Animal Husbandry, Viikki, 07100 Helsinki, Finland 3 Agricultural Research Centre, Swine Research Station, SF-05840 Hyvinkää, Finland Abstract. A digestibility trial, designed as a 5*5 Latin square, with growing pigs was con- ducted to investigate the effect of cooking and enzyme treatment of barley on digestibility and nitrogen utilization. In addition, two piglet performance trials were conducted to investigate the effect of hydrothermal processing of barley and soybean meal and enzyme supplementa- tion of piglet feeds on performance and health status. Five pigs, averaging 40 kg LW, were fitted with T-shaped cannulas in the terminal ileum and fed the experimental diets for five consequtive 12-day experimental periods. Chromic oxide was used as marker. Cooking of barley significantly improved the apparent faecal digestibility (AD) of DM, OM, CP and EE (p0.05). There were no differences in health status between treatments. Index words: barley, cooking, enzyme treatment, enzyme supplementation, digestibility, piglet performance Introduction The purpose of hydrothermal processing of feed raw materials is to rupture the cell wall matrix and modify the chemical structure of the constituents in order to render them more susceptible to enzyme degradation in the small intestine, thus improving the digestibility and utilization of the nutrients. Furthermore, heat treatment of soybeans, beans and peas has been shown to decrease the content of an- tinutritional factors such as trypsin inhibitors, lectins and tannins leading to an increased feeding value (Huisman and Van Der Poel, 1987). Starch is the main constituent in cereals and hydrothermal processing causes changes in the structure of the starch granules, which in- crease their degradability (Fernandes et al., 1975; Lawrence, 1972; 1973 a). Carbohy- drates present in the gut for a long time may constitute substrates for microbial prolifera- tion, resulting in the formation of useful or noxious substances. Non-starch polysaccharides (NSP) and lig- nin, a mixture of compounds known as fibre, are poorly digested by the pig. The amount and type of dietary fibre influence the digest- ibility of nutrients. The higher the content of fibrous material in the diet, the greater also the proportion of dietary and endogenous fat, starch etc. being transferred to the large in- testine probably due to a reduced transit time allowing less time for enzymatic digestion in the small intestine (Just, 1983). Gel-forming polysaccharides such as the beta-glucans together with pentosans are the main components in barley endosperm cell walls. Like barley, oats also contains relatively high amounts of beta-glucans, whereas wheat only contains small amounts (Aman, 1987). Soluble beta-glucans form viscous solutions and in the intestine and tend to gel the con- tents. These gels restrict diffusion of products of digestion and make it difficult for the nutrients to reach the absorptive surface (Krogdahl, 1987). Both water and more ef- fectively beta-glucanase treatment of barley have been shown to reduce extract viscosity and decrease the molecular weight of soluble beta-glucans and pentosans (Hesselman, 1983). The effect of hydrothermal processing on the digestibility and feeding value of cereals has been elucidated in many experiments. The results from processing e.g. wheat and barley have not been consistently positive (Daniel- shn, 1986, Lawrence, 1973 b, Kneale, 1972). An explanation for this could be a decreased availability of the amino acids due to heating. In fact, heat processing of cereals has been shown to decrease nitrogen solubility (Papasolomontos and Wilkinson, 1976) and to reduce the availability of e.g. lysine (Hur- rell and Carpenter, 1981). Alternatives to the conventional processes are of great interest, while it seems that they are connected with some risks regarding the effect on protein quality and production ef- ficacy. In addition, these processes require 686 substantial amounts of energy, which in- creases the costs of the processed raw materi- als. The objective of this report was to elucidate the effect of enzyme treatment of cooked barley on ileal and faecal digestibility and nitrogen balance in pigs. In addition, two per- formance trials were conducted with piglets to investigate the effect of hydrothermal process- ing of barley and SBM and enzyme sup- plementation of piglet diets. Materials and methods Digestibility trial This trial was carried out at the Department of Animal Husbandry of the University of Helsinki. Animals and management Five crossbred (L*Y) castrates, averaging 40 kg LW, were surgically fitted with metallic T-shaped cannulas in the terminal ileum, ap- proximately 15 cm anterior the ileocaecal junction, according to the technique described by Jonsson (1985). Five days after surgery, the pigs were transferred to metabolism cages, where they were housed during the trial. The design of the cages permitted separate collec- tion of urine and faeces. Equal amounts of feed, mixed with water (ratio 1:1), were offered three times a day at 0700, 1500 and 2100 h. The average feed in- take was 1600, 1800, 2000, 2200 and 2400 g per day during the five consequtive experimen- tal periods, respectively. Additional water was offered ad. lib. after each feeding, and con- sumption was recorded during the collection periods. Each experimental period consisted of a 6-day standardisation, a 4-day faecal collec- tion and a 2-day ileal collection period. Faeces were collected for 96 hours starting at 0830 h on day 6 of each experimental period. Dur- ing days 11 and 12, samples of ileal digesta (50 ml) were collected eight times a day with two hour intervals, starting at 0700 h. Each sample was frozen immediately after collect- ing. Prior to analysis, samples were thawed and mixed. Design and treatments The experiment was a 5*5 Latin Square de- sign. Five diets, containing differently treated barley, casein, barley starch (Bst), barley pro- tein (Bpr) and chromic oxide as an indigesti- ble marker, were offered to each pig during the 60-day experiment. Barley was ground (B) and cooked (BC) in diets 1 and 2, respective- ly. In diet 3, cooked barley was treated with alfa-amylase (Novo Industries, Denmark) (BC + A), in diet 4 with alfa-amylase and glucoamylase (Finnish Sugar Co. Ltd.) (BC + AG) and in diet 5 with alfa-amylase and cellulase (Finnish Sugar Co. Ltd.) (BC + AC). The diets were formulated to contain 15 % CP. Due to the low CP content of BC, 2.5 °7o Bpr was added to diet 2 instead ofBst, which was added to the other diets at the same in- clusion level. In addition to the experimental diets, pigs were given 40 g mineral mix (Fos- fori-Hertta) daily and vitamins once a week. Chromic oxide was added at a level of 0.25 % in the diets. The composition of the ex- perimental diets is shown in table 1. Preparation of the raw materials Ground barley (B) was steam heated at 90— 100°C for 60 seconds to a moisture content of approximately 30 % followed by toasting in an oil-heated drum, for about 30 seconds, resulting in a gelatinization of 50—60 % of the starch (BC). The enzyme preparations were sprayed onto the cooked barley during mixing and allowed to act for about 30 min. prior to drying (BC + A, BC + AG and BC + AC). The effect of the treatments on the re- lease of reducing sugars is shown in table 3. The soybean meal used in diets 2 and 3 of trial 1 was extruded by a single-screw extruder. 687 688 Table 1. Composition of the experimental diets, %. Treatment 1 2 3 4 5 Barley (B) 91.75 Barley, cooked (BC) 91.75 BC + A 91.75 BC + AG 91.75 BC + AC 91.75 Casein 5.50 5.50 5.50 5.50 5.50 Bst 2.50 2.50 2.50 2.50 Bpr 2.50 Chromic oxide 0.25 0.25 0.25 0.25 0.25 The exit temperature was approximately 130°C. Analytical methods Dry matter, ash, crude protein, ether extract and crude fibre were determined according to standard methods. NDF and ADF were as- sayed according to Goering and Van Soest (1970). Reducing sugars were determined with the dinitrosalisylic acid (DNS) method (Mill- er, 1959) using glucose as a standard. Chro- mic oxide was analysed by AAS. Amino acids were assayed at the National Laboratory of Agriculture with an automatic amino acid analyser (Chromakon 400) follow- ing hydrolysis and separation by ion-exchange chromatography, and available lysine was de- terminedby difference following pretreatment of the samples with flourodinitrobenzene (Pad et al., 1963). Energy values were calcu- lated according to Finnish feed tables by using the digestibility coefficients obtained from the digestibility trial (Salo et ai., 1982). Statistical analysis Analysis of variance for Latin square ex- periments was used for digestibility measure- ments. Performance trials Experimentals Trial I. This trial was carried out at the Swine Research Station in Hyvinkää. A total of thirty-six new-born litters of L-, Y- and L*Y crossbred sows, comprising 7 or more piglets, were allotted to three treatments of twelve replicates each. Litters from sisters or closely related sows were allocated to differ- ent treatments, which included litters from both gilts and multiparous sows. Table 3. Chemical composition of the raw materials, g/kg DM. Raw material B BC BC +A BC +AG BC +AC Casein Bpr Bst Dry matter 945 948 951 955 947 956 965 939 Ash 26 25 26 26 26 82 42 2 Crude protein 129 122 126 128 127 882 376 7 Ether extract 33 34 38 40 40 10 62 Crude fibre 64 55 66 70 72 15 N-free extracts 748 746 744 736 735 76 520 976 NDF 202 173 200 198 202 ADF 55 42 60 59 62 Reducing sugars* 6 135 201 128 Glucose* <1 II 115 18 * determined in BC, BC +A, BC + AG and BC + AC. Table 2. Composition of the experimental diets, g/kg. Diet Trial 1 Trial 2 12 3 12 Barley 457 Barley, cooked 445 444 Barley, hydrotherm. 421 417 Dehulled oats, steamed 300 300 300 370 370 Soybean meal (SBM) 88 SBM, extruded 100 100 SBM, hydrotherm. 75 75 Fish meal 60 60 60 60 60 Fat blend 5 5 5 Skim milk powder 25 25 25 Whey powder 20 20 Glucose 35 35 35 20 20 Dicalcium phosphate 19 19 19 19 19 Calcium carbonate 3 3 3 5 5 Sodium chloride 1.5 1.5 1.5 2.0 2.0 L-lysine HCI 1.8 1.6 1.6 2.1 2.1 DL-methionine 0.1 0.1 L-threonine 1.0 0.8 0.8 0.7 0.7 Premix* 4.0 4.0 4.0 4.0 4.0 Carbadox, ppm 50 50 50 50 50 Enzyme-premix 1.0 1.0 5.0 ME, MJ/kg, calculated 14.1 14.1 14.1 14.0 14.0 FU/kg, calculated 1.05 1.05 1.05 1.05 1.05 • vitamins and trace elements according to requirements. The piglets were accustomed to the ex- perimental diets from one week of age and had free access to the diets from two weeks to the end of the trial at seven weeks of age. The feeds were provided in self-feeders. Water was provided through nipples and available continuously. The piglets were weaned at 5 weeks by removing the sow from the farrowing pen, in which piglets stayed until the end of the trial. The diets were formulated to have similar chemical composition. In diet 1, barley and SBM were untreated. In diet 2 and 3, all barley and SBM were replaced with cooked barley and extruded SBM, respectively. Because the raw materials were processed at a different feed mill than the one in which the feeds were compounded, different batches were used for diet 2 and 3 than for diet 1. These unfortunate circumstances resulted in a lower CP levels in the first diet. To get diet 3, an enzyme mix- ture containing alfa-amylase, cellulase and protease was added to diet 2. Crude protein, lysine and energy contents of the diets were calculated to be 185 g/kg, 11.5 g/kg and 1.05 FU/kg (14.1 MJ ME/kg, respectively. The composition of the diets is shown in table2. Piglets were individually weighed at birth, at weaning and at the end of the trial. Feed consumption, mortalities and the occurrence and severity of diarrhoea were recorded (scale of severity in table 10). Scouring piglets were treated with antibiotics. Trial 2. In this trial, carried out at Munk- kila Experimental Station in Paimio, forty- eight crossbred (L*Y) piglets, weaned at an age of five weeks and averaging 13 kg in live weight, were allotted to two treatments of twenty-four animals, each group comprising 12 gilts and 12 castrates. Piglets on each treat- ment were allocated to four replicates into pens with six piglets, on sex and live weight basis. There were two pens with gilts and two pens with castrates on each treatment. Dur- -689 ing the 19-day experimental period, piglets were fed ad. lib. from self-feeders, having ac- cess to one feeder per pen. Water was pro- vided through nipples (one per pen) and was available for the animals continuously. All piglets were penned in the same row of an automatically air-conditioned enclosed sec- tion with a row of pens on each side of the central passage. One third of the 1.6*2.4 m concrete floor of the pens was slatted. Pens were partitioned by a 60 cm high solid steel wall and an additional 30 cm steel-pipe con- struction. During the first week, the air tem- perature was 25°C and decreased 2°C weekly. The diets were formulated to contain differ- ent levels of enzyme activities by supplement- ing different amounts of an enzyme-premix containing beta-glucanase (Finnish Sugar Co. Ltd.), alpha-amylase and protease (Novo In- dustries). The basal diet contained hydrother- mally treated cereals and SBM, fish meal, whey powder and glucose. The inclusion lev- els of the enzyme-premix was 0.1 % and 0.5 % in diets 1 and 2, respectively. The lower level represents the inclusion rates used in some commercial feeds. Unfortunately, due to limited facilities it was not possible to in- clude a negative control in this trial. The com- position of the diets is shown in table 2. The feeds were compounded at the Sampola feed mill, pelleted and then crumbled. The piglets were individually weighed at the beginning and at the end of the trial. The feed- ers were refilled once a day according to feed consumption and the amounts were recorded. During the trial, the health status of the piglets was monitored and in case of diar- rhoea, affected piglets were treated with an antibiotic (Orimysin). Analytical methods Feed and amino acid analyses were carried out according to the methods described above. Enzyme activities of the feeds were measured at the Finnish Sugar Research Centre. Alfa- amylase activity was determined by using the Phadebas Amylase Test (Pharmacia). Beta- glucanase activity was determined by measur- ing the rate of production of reducing sugars (Miller, 1959) when beta-glucan was used as a substrate at pFI 5.0 and 30°C. Protease ac- tivity of the feeds was determined according to the method by Matsubara et al. (1958) using casein as a substrate. The energy content of the diets was calcu- lated according to referred values of theFinn- ish feed tables (Salo, et ai. 1982). Statistical analysis Analysis of variance (one way classification) was used for the performance measurements in trial 1. The diarrhoea index values were compared by the ChF-test and mortality values of treatments 2 and 3 were compared to the values of treatment 1 one at a time by using the unpaired Student’s T-test. Mean values of the measurements of trial 2 were compared by unpaired Student’s T-test. Results and discussion Digestibility trial Chemical composition of the diets The chemical composition and amino acid content of the raw materials are shown in ta- bles 3 and 4, respectively. Cooking of barley resulted in a small decrease in the crude pro- tein content. Similar results have been reported when barley was either micronized (Fernandes et al., 1975; Lawrence, 1973 a) or heated (Kneale, 1972). Ether extract and crude fibre content of the enzyme-treated barleys were somewhat higher than in BC. Also the NDF and ADF content of the en- zyme-treated barleys were higher than in BC. The increased levels of NDF may contain some Maillard products, which had escaped the hydrolyzation of the analysis (Van Soest, 1982). The effect of enzyme-treatment on the re- lease of reducing sugars and glucose is shown in table 3. Barley contains about 0.1 %of glu- 690 691 Table 4, Amino acid contents of the raw materials, g/16 gN. Raw material B BC BC +A BC + AG BC + AC casein Bpr Ala 4.2 4.2 4.2 4.2 4.3 3.2 3.9 Arg 5.3 5.3 5.1 5.3 5.1 3.9 4.0 Asp 5.6 6.3 6.3 6.5 6.3 7.7 5.0 Cys 2.7 2.7 2.5 2.6 2.6 0.6 2.2 Glu 23.1 23.1 22.4 21.5 20.3 22.0 21.3 Gly 4.2 4.2 4.3 4.2 4.3 1.9 3.7 His 2.4 2.4 2.2 2.2 2.1 3.0 2.2 He 3.7 3.7 3.5 3.5 3.4 5.5 3.4 Leu 7.4 7.3 7.1 7.1 7.0 10.5 7.1 Lys 3.9 3.9 3.6 3.5 3.6 8.0 3.2 Met 2.2 2.0 1.8 1.8 1.6 2.9 1.8 Phe 5.2 5.4 5.2 5.2 4.9 5.6 5.8 Pro 11.0 10.9 10.3 9.5 9.1 11.5 12.2 Ser 4.4 4.5 4.4 4.4 4.3 5.9 4.3 Thr 3.8 3.7 3.6 3.6 3.4 4.5 3.4 Tyr 3.2 4.5 3.2 3.3 3.4 6.2 3.6 Val 5.1 5.1 5.0 4.9 4.7 6.6 4.7 Available lys 3.4 3.3 3.0 2.8 3.0 7.1 3.1 cose in DM (Äman and Hesselman, 1984) and according to the results cooking of barley did not have any effect on the glucose con- tent. Alfa-amylase in combination with glucoamylase yielded the highest amounts of sugars. The content of first limiting amino acids (ly- sine, threonine, methionine and cystein) was lower in the enzyme-treated barleys than in untreated and cooked barley. Also the amount of available lysine was smaller in the enzyme- treated barleys. This indicates that some browning reactions (Maillard-reactions) have occurred. These reactions between the car- bonyl group of a reducing sugar and a free amino group of an amino acid or protein re- duce the availability of susceptible amino acids, especially lysine (Hurrell and Car- penter, 1981). The marked increase in the concentration of reducing sugars in the en- zyme treated barleys seems to have increased the incidence of these reactions. Apparent digestibility Due to problems in obtaining representative samples of the ileal digesta and in recovering the chromic oxide, the results of the ileal di- gestibility of the diets were too confusing to be interpretable. Therefore, these results will not be presented in this paper. The apparent digestibility (AD) coefficients of the diets, determined by direct assay, are presented in table 5. The AD of ground barley was similar to that reported by Näsi (1984), with the exception of AD of CF, which was higher in the present trial. Micronizationof barley increases the digest- ibility of DM, nitrogen and gross energy (Fernandes et al., 1975; Lawrence, 1973 a). In this present trial, cooking of barley signifi- cantly (p<0.05) increased the AD of DM, ash, OM, CP and EE. Also the AD of CF was improved, but not significantly. AD of DM (p<0.05) and OM (p < 0.01) in BC was sig- nificantly higher than in B, BC + A and BC + AG and approximately the same as in BC + AC. Enzyme treatment of BC decreased the AD of most nutrients to the same level as in ground barley. Only the AD of EE was higher in the enzyme treated barleys than in B (p<0.05). The AD coefficients of BC + AC were the highest among the enzyme-treated barleys. There were no significant differences in AD of CP between B and the enzyme- Table 5. Apparent digestibility of the diets, °/o (direct assay). Treatment 1 2 3 4 5 SEM DM 80.6b 85.4a 80.6b 80.7 b 81.9ab 0.681 Ash 38.5 48.0 41.4 39.8 45.2 2.632 OM 82.6M 87.1“ 82.5bd 82.7 bd 83.7“ 0.592 CP 78.0b 84.6a 82.9ab 82.4 ab 84.1 ab 1.138 EE 39.8d 59.2 C 60.9" 59.9" 65.7' 2.376 CF 19.9 31.0 7.4 19.5 17.6 3.675 NEE 90.6ab 92.6a 89.3b 89.5b 90.3ab 0.450 CCH 85.1 abcd 88.5“ 83.2bd 83.6b'd 84.3 b' d 0.646 NDF 44.1 ab'd 53.9“ 32.9 bd 37.4“ 40.3 ab'd 2.6 ADF 3.7 18.1 —5.7 3.3 9.1 4.198 a b (p<0.05); c d (p<0.01) treated barleys. The AD of NFE and CCH in BC A and BC +AG were significantly low- er than in BC (p<0.05). This may be a con- sequence of the browning reactions that oc- curred, resulting in poorly digestible com- plexes of sugars and amino acids. The AD of OM and CCH was significantly lower in BC + AC than in BC. OM and CCH include crude fibre. Treating cooked barley with enzymes markedly decreased the AD of CF, which consequently also was seen as a reduced AD of OM and CCH. The low AD coefficients of CF and the detergent fibre frac- tions of the enzyme treated barleys are prob- ably a result of the action of the enzymes. Treating BC with enzymes yielded reducing sugars mainly from starch, but to some extent from some fiber fractions leaving more insolu- ble fractions intact. The residual fibres are thus even less digestible. In young pigs, beta-glucanase supplemen- tation of barley has improved performance and the digestibility of energy (Thomke et al., 1980) and crude protein (Markström et al., 1985). In a digestibility trial with pigs from 30 to 50 kg Lw Graham et al. (1986) did not obtain any significant improvement of the di- gestibility when a barley-based diet was sup- plemented withbeta-glucanase. The apparent ileal digestibility of beta-glucan was found to be 68 % in the unsupplemented and 72.3 % in the supplemented diet (p>0.05). These values corresponds well to the ones of 76 — 82.2 % reported by Weltzien and Aherne (1986) working with somewhat heavier pigs. Thacker et al. (1988) reported improvement in the digestibility of dry matter, crude pro- tein and digestible energy of beta-glucanase supplemented hulless barley in pigs weighing 40 kg. However, these improvements in the digestibility were not reflected in significant improvements in theperformance of thepigs. In performance trials, enzyme supplementa- tion of barley based diets have improved the feeding value of the diets for pigs (Collier and Hardy, 1986; Newman, 1983). In the present trial, cooking markedly increased the digestibility of barley leaving less potential for improvements by the enzyme treatments. The N-balance of the treatments is shown in table 6. Nitrogen intake and absorption was highest on treatment 2 and lowest on treat- ment 1, resulting in the highest apparent di- gestibility of N on treatment 2 with slightly lower values for the enzyme treatments. Urine nitrogen excretion, however, was highest on treatment 2 and lowest on treatment 3, result- ing in the highest N retention for this latter treatment. The amount of nitrogen retained, calculated as per cent of both N intake and absorption, was higher on all enzyme treat- ments than on treatment 1 and 2. Consequent- ly, biological value of the nitrogen was im- proved by the enzyme treatments. Due to large variation within treatments, none of the parameters was significantly different. Zebrowska (1973) showed that nitrogen absorbed from the large intestine was excreted 692 in the urine, and did not contribute to the pro- tein synthesis of the pig. Just (1982) calcu- lated the energy excretion into the urine to be 30.6 kJ/g nitrogen (included in urea and oth- er nitrogenous substances). It is a well known fact that the higher the nitrogen intake the higher the AD of the nitro- gen. The unabsorbed nitrogen arriving in the large intestine will, depending on the amount of fermentable substrates available for the mi- crobes, either be incorporated in to the microbial tissue or deaminated and absorbed as NH4 and subsequently excreted in the urine as urea. The decreased N excretion in the faeces and the increased N (and urea) ex- cretion in the urine on treatment 2 (BC) sug- gest that cooking of barley improved the ab- sorption of carbohydrates in the small intes- tine leaving less substrates for microbial fer- mentation and proliferation in the large intes- tine. This is in good accordance with the AD values of OM and NFE. On the enzyme treat- ments the average N intake, absorption and urinary N were approximately 4 g/d less than on treatment 2, resulting in a relatively better N utilization, shown as higher BV values. Lawrence (1973 a) did not find any im- provement in nitrogen retention, when barley and maize were micronized and fed to pigs. The results from this present trial, however, indicate an increased nitrogen (amino acid) absorption in the small intestine resulting in an improved protein utilization following both cooking and the subsequent enzyme treatment of barley. The decrease in available lysine con- tent of the enzyme treated barleys did not seem to have any adverse effect on protein utilization. In the small intestine starch is hydrolyzed by a variety of enzymes including e.g. amy- lases, maltases and glucoamylases, and is degraded into glucose, which can be rapidly absorbed by the mucosa (Kidder and Man- ners, 1978). The rate of glucose absorption from various sources varies from one carbo- hydrate to another and from one intake level to another (Rerat, 1985). The first peak of sugars in the portal blood was reached very quickly (45 min.) after glucose and sucrose in- take, but later (2 hrs.) after intake of maize starch. Large amounts of starch were found in the digestive tract 8 h after the meal, where- as absorption of glucose and digestion of su- crose was much advanced. Irrespective of the type of carbohydrate, its degradation in the large intestine leads to the production of acetic, propionic, butyric (VFAs) and lactic acid and small amounts of other organic acids in addition to ethanol, car- bon dioxide, methane, hydrogen and small amounts of other gases. The organic acids are readily absorbed and serve the body as an energy source (Just, 1983). According to Low (1980), VFA may provide 2—3 % of the apparently absorbable energy intake of grow- ing pigs. However, the higher the VFA con- centration in faeces, the lower the utilization of ME (Just, 1983). Table 6. N-balance, protein utilization and biological value of the diets. Treatment 12 3 4 5 N intake, g/d 38.3 48.0 44.1 45.4 43.0 N in faeces, g/d 8.0 7.4 7.6 7.8 6.8 N absorbed, g/d 30.4 40.7 36.5 37.6 36.1 Apparent dig., °7o 78.0 84.6 82.9 82.4 84.1 N in urine, g/d 15.4 18.4 13.6 15.6 15.7 N retained, g/d 14.9 22.3 22.9 22.0 20.4 % of intake 37.2 45.8 52.8 47.8 47.4 of absorbed 46.9 53.9 63.8 58.0 56.4 g/kgW075 0.74 1.02 1.16 1.07 1.08 BY 57.1 61.8 71.2 65.8 64.0 Urea excreted, g/d 22.2 24.8 19.9 19.5 21.5 g/kgW07 Vd 1.05 1.11 0.94 0.95 1.13 693 694 Table 7. Calculated energy values and digestible crude protein. Raw material B BC BC +A BC + AG BC + AC FU/kg DM 1.09 1.17 1.10 1.11 1.12 Kg/FU 1.05 0.98 1.01 1.01 0.99 ME MJ/kg DM 14.27 15.32 14.45 14.53 14.75 NE MJ/kg DM 8.82 9.61 8.96 9,02 9.13 DCP, g/kg DM 91.5 96.7 98.2 98.8 101.2 DCP, g/FU 83.91 82.65 89.11 89.26 90.13 Feeding values of the differently treated barleys were calculated using the digestibility coefficients of the nutrients obtained from the digestibility trial. The results are presented in table 7. Cooked barley had the highest ener- gy value followed by BC + AC, BC + AG, BC + A and B, in that order. On ME basis, the energy content of BC was 7.3 % and that of BC +A, BC +AG and BC +AC 1.3, 1.8 and 3.4 % higher than that of B, respective- ly. Digestible crude protein (DCP) content of the enzyme treated barleys was higher than in B and BC. An increased absorption of degrad- ed carbohydrates from the small intestine and the increased nitrogen retention following cooking and enzyme treatment of barley may explain the increased energy values. Performance trials Trial 1 The chemical composition of the diets is shown in table 8. Different batches of barley and SBM were used for processing and, con- sequently, the crude protein content of diets 2 and 3 was 0.8 ®7o higher than in diet 1. Also the sodium chloride content was higher in diets 2 and 3. The amino acid contents of the diets were similar. Due to a dosage mistake, however, doubleamounts of L-threonine was added to diet 2, which can be seen as a higher threonine content in that diet. Piglets on treatment 1 had significantly (p<0.05) higher live weights at 8 weeks of age and gained significantly (p<0.05) more Table 8. Chemical composition of the experimental diets, g/kg. Diet Trial 1 Trial 2 12 3 12 Dry matter 891 893 888 893 892 Crude protein 183 191 191 175 176 Ether extract 34 36 39 34 31 Crude fibre 34 35 36 32 31 Ash 54 64 60 54 52 N-free extracts 586 567 562 598 602 Salt (NaCI) 5.6 10,1 8.2 5.7 5.2 Calsium 10.3 11.2 11.1 8.7 8.2 Phosphorous 10.0 10.0 10.2 7.2 7.6 Lysine 10.8 11.3 11.2 10.3 11.0 Available lysine 10,1 10.7 10.5 Methionine 4,1 4.0 4.0 3.8 3.7 Threonine 7.5 8.8 7.8 7.3 7.4 Tryptophan (cal.) 2.4 2.4 2,4 2.4 2.4 Alfa-amylase, U/kg nd* 1850 Beta-glucanase, U/kg 2700 3750 Protease, U/kg 5140 6000 * not detectable 5 Table 9. Piglet performance during the experimental period, mean values. Treatment 1 2 3 sign. SEM Piglets 120 139 131 Live weight, kg/piglet at birth 1.58 1.53 1.57 NS 0.027 at 5 weeks of age 9.61 9.05 9.33 NS 0.181 at 8 weeks of age 19.34a 18.14b 18.39b * 0.315 Live weight gain, g/d/piglet from birth to 5 weeks 230 215 222 NS 4.85 from 5 to 8 weeks 464» 427 b 430b * 9.15 from birth to 8 weeks 317 297 300 Feed intake, kg/piglet from birth to 5 weeks 0.49 0.44 0.63 NS 0.107 from 5 to 8 weeks 15.88 14.33 15.31 NS 0.708 from birth to 8 weeks 16.37 14.77 15.94 Feed conversion, kg feed/kg gain from 5 to 8 weeks 1.66 1.59 1.70 NS ab treatment means with different superscripts are significantly different (p < 0.05) weight from weaning to the end of the ex- perimental period than piglets on treatment 2 and 3 (table 9). Feed intake was not signifi- cantly affected by treatment, but was highest on treatment 3 and lowest on treatment 2. There were no difference in feed utilization be- tween treatments. Extrusion of barley decreased DWG and resulted in a higher feed conversion ratio than untreated barley (Danielsen, 1986). A decreased availability of amino acids, caused by the heat treatment (140°C), could explain the inferior performance. In the present trial, however, the amount of available lysine was slightly higher in diets 2 and 3. Steam-cook- ing (autoclaving, 100 and 120°C), drum dry- ing (I2O°C) (Danielsen, 1986), steam flaking (Aumaitre, 1976) and micronization (80— I4O°C) (Danielsen 1986; Lawrence, 1973 a) of barley improved DWG and feed utilization compared with untreated barley. In contrast, extrusion of a barley-wheat mixture (50 : 50) did not improve piglet performance. Neither did drum drying (115—-155°C) of wheat, rye and barley improve performance of early- weaned piglets from three to seven weeks of age (Danielsen, 1986). Performance of pigs between 33 and 80 kg LW was not improved by micronization of barley (Fernandes et al., 1975). Also flaking of barley resulted in poorer growth rates and feed utilization in ba- con pigs (Lawrence, 1972). Again, a decreased availability of amino acids, caused by the heat treatment, could possibly explain the poor performance results. As was reported above, cooking barley sig- nificantly increased the apparent digestibility and energy value. In addition, extrusion of SBM increased the digestibility and improved performance of pigs, although not significant- ly (Näsi, 1987). According to these results, an improved piglet performance could be ex- pected when cooked barley and extruded SBM are fed together in the same diet. However, the results from thepresent trial suggest that the heat processing methods used (T> 130°C) had a negative effect on the nutritive values of the feeds. Enzyme supplementation of diet 2 (treat- ment 3) did not improve piglet performance. If, as could be concluded from these results, cooking and extrusion had a negative effect on the nutritive values of barley and SBM, respectively, enzymes cannot be expected to reverse this effect usually being a result of ir- reversible reactions (e.g. Maillard). Conse- quently, the lack of response seems quite log- ical. 695 Table 10. Health status of the piglets during the experimental period, mean values of litters. Treatment 1 2 3 signific. Diarrhoea indexA 148a 284b 304b ** Mortality, % from start to 5 weeks 0.83 1.44 1.53 NS from 5 to 8 weeks 0.00“ 2.19b 1.55“ * from start to 8 weeks 0.83 3.60 3.05 NS Litters with no diarrhoea 7 6 4 Litters medicated due to diarrhoea ab treatments means with different superscripts are significantly different (* p<0.05, ** p<0.005) A scale of severity; 1 =normal faeces, 2 =soft faeces, 3 =fluid faeces, 4 =moderate diarrhoea, 5 = severe diarrhoea index =severity * number of affected piglets • days Health status of the piglets on treatments 2 and 3 was inferior to that of piglets on treat- ment 1 (table 10). Diarrhoea index of treat- ment 3 was on the same level as on treatment 2, whereas treatment 1 had a markedly lower index (p< 0.005). Mortality percentage on treatment 2 was higher (p<0.05) than on the other treatments. As mentioned above, the elevated levels of sodium chloride in diets 2 and 3 may have increased the incidence of di- arrhoea on those treatments. Aumaitre (1976) reported increased frequency of diar- rhoea following steam flaking and popping of barley. This was explained by the slightly higher feed intake from the very first days fol- lowing weaning. In the present trial, howev- er, feed intake was highest on treatment 1. Piglets on treatment 2 had the highest mor- tality both before and after weaning. Seven litters our of twelve on treatment 1 were not affected by diarrhoea. Corresponding figures for treatment 2 and 3 were 6 and 4, respec- lively. None of the litters were medicated due to diarrhoea. The sodium chloride content of diets 2 and 3 was markedly higher than in diet 1. It is well known that high intake of salt causes symp- toms such as increased water consumption, which can lead to diarrhoea and edema (Wright, 1972). An increased occurrence of diarrhoea was recorded on treatments 2 and 3 (table 10). It is not possible to find out to what extent this was caused by the elevated sodium chloride levels. Trial 2 The chemical composition of the diets did not differ exept regarding the lysine content and enzyme activity (table 8). The lysine con- tent of diet 2 was slightly higher than in diet 1. The results from the enzyme activity anal- ysis indicate high levels of naturalactivity, es- pecially of beta-glucanase and protease. Table 11. Performance during the experimental period, mean values per piglet. Treatment I sd 2 sd 1.3 2.4 1.8 92 1.4 0.04 sign. Piglets 24 24 Initial weight, kg Final weight, kg Weight gain, kg Daily weight gain, g Feed intake, kg 13.2 1.3 13.4 23.5 3.0 24.5 NS NS NS NS NS 10.3 2.6 135 11. 1 542 586 18.8 1.0 19.0 Feed/gain, kg/kg 1.83 0.13 1.70 NS =not significant 696 697 Piglets on treatment 2 had higher live weights at the end of the trial, gained more weight and consumed more feed than piglets on treatment 1. Feed utilization was improved on treatment 2. Due to considerable variation within the treatments, none of the performance param- eters was significantly different between treat- ments. The marked improvement of performance by the higher inclusion level of enzyme activi- ties indicate that the digestive capasity of young pigs can be enhanced by enzyme sup- plementation of the diet. Enzyme pre-treat- ment of barley, using a mixture of carbohy- drate, starch and protein degrading enzymes, markedly decreased the incidence and severi- ty of post-weaning diarrhoea (Inborr and Ogle, 1988). Thomke et al. (1980) reported improved performance of piglets when fed high viscosity barley supplemented with beta- glucanase. Accordingly, Collier and Hardy (1986) and Newman (1983) reported im- proved performance of pigs following enzyme supplementation of barley-SBM based diets. Conclusions Cooking of barley significantly improved the digestibility of barley. A subsequent en- zyme treatment of the cooked barley de- creased the digestibility to the same level as before cooking. This may have been a conse- quence of the browning reactions between reducing sugars and lysine resulting in poorly digestible complexes. This was indicated by the markedly elevated concentrations of glu- cose and the decreased amounts of available lysine in the enzyme treated barleys. The results from the N balance measure- ments indicate a change in the availability of the energy following the treatments of barley. All treatments seemed to improve the energy uptake from the small intestine, but the en- zyme treatments resulted in a relatively bet- ter N utilization than cooking. In the piglet performance trials enzyme sup- plementation of the diets did not give any con- clusive results. In trial 1, the lack of response was probably a consequence of the inclusion of heat damaged raw materials (cooked barley and extruded SBM, T>l3o°C), resulting in impaired performance. In trial 2, an increased enzyme activity inclusion rate in a diet con- taining hydrothermally treated barley and SBM (T <6O°C) resulted in improved perfor- mance, suggesting that more gentle heat processing methods would be preferable in order to leave more potential for supplemen- tal feed enzymes. References Aumaitre, A. 1976. Evaluation de divers traitments tech- nologiques des cereals. IV. Influence du floconnageet de I’expansion de Forge et du mais sur les performances du porcelet serve a 21 jours: effets sur la digestibilite des elements de la ration. Ann. Zootech., 25: 41—51. Björnhag, G. & Jonsson, E. 1983. Replacable gastro- intestinal cannulas for small ruminants and pigs. Livest. Prod. Sci. 11: 179—184. Collier, B. & Hardy, B. 1986. The use of enzymes in pig and poultry feeds. Feed Compounder 6 (4); 28—30. Danieisen, V. 1986. Varmebehandlet korn till smägrise. Hyologisk Tidskrift No. 11, pp. 50—51. Fernandes, T.H., Flutton, K. & Smith, W.C. 1975. A note on the use of micronized barley for growing pigs. Anim. Prod., 20; 307—310. Graham, H., Hesselman, K., Jonsson, E. & Äman, P. 1986. Influence of beta-glucanase supplementationon digestion ofa barley-based diet in the pig gastrointes- tinal tract. Nutr. Rep. Int., Vol. 34, No. 6: 1089—1096. Goering, H.R. & Van Soest, P.J. 1970. Forage fibre analysis. Agricultural Handbook No. 379. United States Dept, of Agric. Washington. Hesselman, K. 1983. Ph. D. thesis. Swedish Univ. of Agric. Sci. Cited in Hesselman, K and Äman, P. 1985. A note on microscopy studies on water and bets- glucanase treated barley. Swedish J. agric. Res. 15: 139—143. Huisman, J. & Poel, A.8.F., Van Der. 1987. Effects on antinutritional factors (ANE) in pig nutrition. 38th annual meeting of the EAAP., Lissabon, Portugal. Manuscript, pp. 14. Hurrell, R.F. & Carpenter, K.J. 1981. The estimation of available lysine in foodstuffs after Maillard reac- tions. Prog. Fd. Nutr. Sci. Vol. 5. pp 159—176. Inborr, J. & Ogle, R.B. 1988. Effect of enzyme treat- ment of piglet feeds on performance and post wean- ing diarrhoea. Manuscript. Submitted for publication. Just, A. 1982. The net energy value of crude (catabo- lized) protein for growth in pigs. Livest. Prod. Sci., 9: 349—360. 1983. The role of the large intestine in the digestion of nutrients and amino acid utilization in monogastrics. IV Int. Symp. on Protein metabolism and nutrition. Ed. INRA, Pubi. I (les Colloques de ITNRA, No. 16). Kidder, D.E. & Manners, M.J. 1978. Digestion in the pig. Bath (UK), pp. 201. Kroodahl, A, 1987. Dietary fibres are trouble makers. Poultry international, april ’B7, p. 20—24. Kneale, W.A. 1972. Effect of heat on the feeding value of barley in rations for bacon pigs. Exp. Husb. 21: 69—77. Lawrence, T.L.J. 1972. High level cereal diets for the growing/finishing pig. VI. An evaluation of flaked maize, wheat and barley when included at high levels in the diet of the weaned pig grown to cutter weight (160 lb). J. Agric. Sci., Camb., 79: 155—160. 1973 a. An evaluation of the micronization process for preparing cereals for the growing pig. 1. Effects on di- gestibility and nitrogen retention. Anim. Prod. 16: 99—107. 1973 b. An evaluation of the micronization process for preparing cereals for the growing pig. 2. Effects on growth rate, food conversion efficiencyand carcass characteristics. Anim. Prod. 16: 109—116. Low, A.G. 1980. Nutrient absorption in pigs. J. Sci. Food Agric., 31, 1087—1130. Markström, 8., Pettersson, D. & Hesselman, K. 1985. Betaglukanas tillsats till grov- och finmalet korn ett smältbarhetsförsök med smägrisar. Sveriges Lantbruk- suniversitet, Inst, för husdjurens utfodring och värd. Rapport 149. Matsubara, H., Haoihara, 8., Nakai, M., Komaki, T., Yonetani, T. & Okunuki, K. 1958. J. Biochem., Vol. 45: 251—258. Miller, G.L. 1959. Anal. Chem. 31, 426—428. Newman, C.W., Eslick, R.F., Pepper, J.W. & Elnegou- my, A.M. 1983. Performance of pigs fed hulless and covered barleys supplemented with or without a bac- terial diastase. Nutr. Rep. Int., Vol. 22, No 6: 833 837. Noland, P.E., Campbell, D.R., Gage, Jr., R.K., Sharp, R.N. & Johnson, Z.B. 1976. Evaluation of processed soybeans and grains in diets for young pigs. J. Anim. Sci. 48: 763—769. Näsi, M. 1984. Trämelass som svinfoder. NJF seminar No. 57, 16:1, Stenhamra, Sweden. 1987. The feeding value of differently treated soybean meals for pigs. Unpublished. Pao, S.R., Carter, F.L. & Frampton, V.L. 1963. Anal. Chem. 35, 1927—1930. Papasolomontos, S.A. & Wilkinson, J.I.D. 1976. In Op- timizing the utilization of cereal energy by cattle and pigs, p. 31. London; US Feed Grains Council. (Cited in Recent advances in animal nutrition, 1978. Eds. Haresign, W and Lewis D. Pubi, Butterworths, Lon- don.) Rerat, A.A. 1985. Intestinal absorption of end products from digestion of carbohydrates and proteins in the pig. Arch. Tierernähr., 35; 7: 461—480. Salo, M-L., Tuori, M. & Kiiskinen, T. 1982. Re- hutaulukot ja ruokintanormit. 70 p. Helsinki, Soest, P.J. Van. 1982. Nutritional ecology of the ruminant. O&B Book Inc., Corvallis, OR. Thacker, P.A., Campbell, G.L. & Grootwassink, J.W.D. 1988. The effect of beta-glucanase supplemen- tation on the performance of pigs fed hulles barley. Unpublished. Manuscript, pp. 8. Thomke, S., Rundgren, M & Hesselman, K. 1980. The effect of feeding high-viscosity barley to pigs. 31st an- nual meeting of the European Association of Animal Production, Munich, FRG. Commission on animal nutrition. Stencil, pp. 5. Weltzien, E.M. & Aherne, F.X. 1986. The effect of anaerobic storage and processing of high moisture barley on its amino acid and beta-glucan digestibility by growing swine. Can. J. Anim. Sci., Vol. 66: 1186— 1187. Wright, D.L. 1972. Sodium salt poisoning in swine. Southwest Vet. 25 (4): 319—320. Zebrowska, T. 1973. Digestion and absorption of nitrog- enous compounds in the large intestine of pigs. Roczn. Nauk. Roln, 958: 85. Äman, P. 1987. Analys och kemisk sammansättning av svensk spannmäl. Fakta husdjur, nr 3. Sveriges Lantbruksuniversitet. & Hesselman, K. 1984. Analysis of starch and other main constituents of cereal grains. Swedish J. Agric. Res. 14: 135—139. Ms received 698 SELOSTUS Entsyymikäsittelyn vaikutus esikypsennetyn ohran sulavuuteen sekä entsyymilisäyksen vaikutus porsasrehun tuotantovaikutukseen J. Inborn, 1 M. Näsi2 and K. Suomi3 1 Suomen Sokeri Oy, Finnfeeds Ltd Forum House, Brighton Road, Redhill, Surrey RHI 6YS, England 2 Helsingin Yliopisto, kolieläinlieleen laitos, Viikki, 07100 Helsinki 3 Maatalouden tutkimuskeskus. Sikatalouden tutkimusasema 05840 Hyvinkää Kasvavilla sioilla tehdyssä sulavuuskokeessa tutkittiin esikypsennyksen ja esikypsennyksen jälkeen suoritetun entsyymikäsittelyn vaikutusta ohran sulavuuteen ja val- kuaisen hyväksikäyttöön. Kahdessa porsaskokeessa tut- kittiin ohran ja soijarouheen lämpökäsittelyn sekä rehuun lisätyn entsyymiseoksen vaikutusta kasvuun, rehun hy- väksikäyttöön jaripulin esiintymiseen. Sulavuuskokeessa oli viisi sikaa, joiden keskimääräi- nen elopaino kokeen alkaessa oli 40 kg. Koe toteutettiin 5x5 latinalaisena neliönä ja jaksojen pituus 12 päivää. Esikypsennys paransi merkitsevästi jauhetun ohran ko- konaissulavuutta ja energia-arvoa. Esikypsennetyn ohran entsyymikäsittely alensi sulavuutta jauhetun ohran tasolle. Esikypsennys paransi typen hyväksikäyttöä ja biologista arvoa (BV). Entsyymikäsittelyn vaikutus typen hyväksi- käyttöön ja biologiseen arvoon oli suurempi kuin esikyp- sennyksen. Esikypsennetyn ohran rehuarvo oli 1,17 ry/kg k.a. (15,32 MJ ME/kgk.a.) ja jauhetun ohran 1.09ry/kg k.a. (14,27 MJ ME/kg k.a.). Entsyymikäsiteltyjen ohrien re- huarvot olivat esikypsennetyn ohran ja jauhetun ohran välillä. Ensimmäisessä porsaiden kasvatuskokeessa 36 pahnuet- ta jaettiinkolmeen ryhmään. Koerehut olivat vapaasti saa- tavilla toisesta viikosta syntymän jälkeenkahdeksanteen elinviikkoon asti. Porsaat vieroitettiin viiden viikon iäs- sä. Kontrollirehussa (ryhmä 1) oli jauhettuaohraa ja soi- jarouhetta.Toisessa koerehussa (ryhmä 2) oli esikypsen- nettyä ohraa ja ekstrudoitua soijarouhetta. Kolmas koe- ryhmä sai toisen koeryhmän rehua, johon oli lisätty ent- syymiseos (ryhmä 3). Ryhmien 2 ja 3 porsaiden keskimääräinen loppupaino japainonlisäys olivat merkitsevästi (p<0,05) pienemmät kuin kontrolliryhmän. Rehujen syöntimäärissä jahyväk- sikäytössä ei ryhmien välillä ollut eroja. Ripulia esiintyi koeryhmässä merkitsevästi enemmän kuin kontrolliryh- mässä. Toisessa kasvatuskokeessa 48 vastavieroitettua porsasta jaettiin kahteen ryhmään. Kummankin ryhmän porsaat jaettiin neljään kuuden porsaan ryhmään. Rehut olivat vapaasti saatavilla koko 19päivän koejakson ajan. Re- hujen koostumus oli sama, mutta koerehuun (ryhmä 2) entsyymiseoksen lisäystaso oli viisinkertainen (0,5 %) ver- rattuna kontrollirehuun (0,1 %). Koeryhmän lisäkasvu oli 8 % ja rehun hyväksikäyttö 7 % parempi kuin kontrolliryhmän. Erot eivät olleet mer- kitseviä (p<0,05). Terveydentilassa ei ollut eroa ryhmien välillä. 699