Nutritive value of three cultivars of triticale for sheep, pigs and poultry

Animal Feed Science and Technology, 18 (1987) ,19-35 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

19

Nutritive Value of Three Cultivars of Triticale for Sheep, Pigs and Poultry E. CHARMLEY’ and J.F.D. GREENHALGH School of Agriculture, University of Aberdeen, 581 King Street, Aberdeen AB9 1 UD (Gt. Britain) (Received 3 November 1986; accepted for publication 8 January 1987)

ABSTRACT Charmley, E. and Greenhalgh, J.F.D., 1987. Nutritive value of three cultivars of triticale for sheep, pigs and poultry. Anim. Feed Sci. TechnoL, 18: 19-35. Three varieties of triticale, ranging in crude protein content from 108 to 192 g kg-’ DM, were compared with wheat in digestibility trials conducted on sheep, pigs, chicks and cockerels to estimate metabolizable energy (ME) for sheep and poultry and digestible energy (DE) for pigs. Classical balance trials were conducted on sheep, pigs and chicks, but ME was determined in cockerels by the true ME method. In sheep, all cereals had similar ME values (13.03 MJ kg-’ DM) . In pigs the mean DE value of the triticale varieties was significantly lower at 15.11 MJ kg-’ DM than the value of 16.03 MJ kg-’ DM for wheat, however, differences between the triticale varieties were small and non-significant. In poultry, as with pigs, wheat had a significantly higher ME than triticale. For chicks, the ME value of one variety of triticale was significantly lower than all others, but, with cockerels, there were no differences in ME between the three varieties of triticale.

INTRODUCTION

Triticale is an intergeneric hybrid of wheat ( Z’riticum spp. ) and rye (Secale cereale) . It has been grown commercially in the U.K. on a small scale for several years. The crop is more tolerant than wheat to dry conditions or low fertilizer nitrogen input and relatively resistant to many of the foliar diseases important in winter cereals. Nutritionally, triticale can have a high protein content with a well balanced supply of essential amino acids (Villegas et al., 1970). In the past, the value of the crop has been limited by low yield and the length of the straw. Recently high-yielding, short-strawed varieties have been developed which are of greater commercial potential (Gregory, 1979). ‘Present address and address for correspondence: Animal Research Centre, Agriculture Canada, Ottawa, Ontario KlA 0C6 Canada.

0377-8401/87/$03.50

0 1987 Elsevier Science Publishers B.V.

20 In ruminants, the digestibility of triticale has been shown to be similar to that of wheat (Sherrod, 1976; Felix, 1980; Felix et al., 1985) and maize (Felix et al., 1985). There are no recorded values for the metabolizable energy (ME) of triticale, but its gross energy (GE) content is similar to that of wheat (National Research Council, 1982 ). Results from production trials, however, show that ruminant performance from triticale is less than from other cereals, in spite of a higher protein content (Dinusson, 1971). It was suspected that ergot contamination was responsible. In other studies using triticale free of ergot, animal performance was poorer than with maize (Jordan and Hanke, 1972) or wheat (Reddy et al., 1975 ). In pig diets, the mean digestible energy (DE) content of triticale recorded in four experiments was 15.94 MJ kg -1 DM (Cornejo et al., 1973; Erickson et al., 1979; King, 1980 and Farrell et al., 1983 ). This value is similar to the published value for wheat (15.36 MJ kg -1 DM), but higher than that of barley (14.73 MJ kg -1 DM) and lower than that of maize (16.04 MJ kg -1 DM) (National Research Council, 1982). Although similar in DE value to wheat, triticale has promoted poorer rates of growth, these being attributed to reduced intake arising from either ergot contamination ( Shimada et al., 1974) or trypsin inhibition (Erickson et al., 1979). Recent work with triticale varieties developed in Australia has shown that even when intake is not reduced, the inclusion of triticale in pig diets will reduce feed conversion efficiency and gain (King, 1980). For poultry, as with pigs, the apparent ME or true ME (TME) values are similar to those of wheat ( Salmon, 1984), but lower than those of maize ( Shimada and Cline, 1974; Halvorsen et al., 1983). The mean apparent ME value from four experiments was 14.26 MJ kg -~ DM (Shimada and Cline, 1974; Yaqoob and Netke, 1974; McNab and Shannon, 1975; Rao et al., 1976) and the mean TME from two experiments, 15.89 MJ kg -~ DM (Halvorsen et al., 1983; Salmon, 1984). The adverse effects that triticale has on intake and growth in ruminants and pigs are less frequently observed in poultry. However, when triticale replaces other cereals on an equal-protein basis, performance may be reduced (Sell et al., 1962). Evidently, protein quality or availability may be lower in triticale than in protein concentrates. The objective of this work was to compare, in three species of animal, the nutritive value of three triticale varieties with that of wheat. The three varieties of triticale were chosen because they covered a wide range of crude protein (CP) content (108-192 g kg- ~DM). They were agronomically suited to U.K. conditions and represented an old established, long-strawed variety (Aquarius), a recently established variety (Lasko) and a new unlisted variety from the Plant Breeding Institute (PBI 121 ). A bread-making wheat variety (Norman) was chosen as the control. Nutritive value was assessed in terms appropriate to the animal species, these being ME for sheep and poultry and DE for pigs.

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MATERIALSAND METHODS Four trials were conducted, In the first, sheep were given the cereals in three combinations with hay; in the second, pigs were given the cereals, either alone or supplemented with protein concentrates and in the third, broiler chicks were given the cereals with supplements of protein concentrate in a conventional balance trial t o determine apparent ME. The T M E was determined in cockerals given a restricted amount of the test cereal.

Diet preparation For all trials except the T M E poultry trial, the cereals were ground in a plate mill (Alvan B l a n c h Ltd. ). In the T M E poultry trial, the cereals were hammer milled to pass through a 5-mm screen. The cereals for the sheep trial were pelleted ( l l - m m die; Lister, Hawker Siddeley) before feeding.

Sample analysis Food samples were dried in a forced-draught oven for 12 h at 100 °C for the determination of DM and ground through a 6-mm screen. Dried samples were analyzed for ash in a muffle furnace at 550°C for 12 h. Nitrogen (N) was determined by the micro-Kjeldahl technique. CP for all the cereals was estimated as NX 6.25. Samples for amino acid analysis were hydrolysed by reflux with 6 M HC1 for 24 h under nitrogen. Separation and determination of the individual amino acids was carried out using a Technicon T S M amino acid analyser. Acid detergent and neutral detergent fibre (ADF and NDF) were determined by the methods of Goering and Van Soest (1970). GE was determined using an adiabatic bomb calorimeter. Faeces and excreta samples were analyzed on a fresh basis for determination of nitrogen by the Kjeldahl technique. Ash, ADF, NDF and GE were determined on freeze-dried samples by the same methods described for food. The DM content was determined either after 24 h at 100 ° C in a forced-draught oven ( sheep and pig trials) or by drying to constant weight at 60 °C (apparent ME poultry trial). Urine was analyzed for N by the micro-Kjeldahl technique.

The sheep trial Twelve wether lambs (Suffolk cross), initially 5 months of age and weighing 35 kg were used. They were housed individually in pens during adaptation periods and in crates during collection. Hay and concentrates were offered twice daily with any residues being removed prior to the morning feed. A mineral and vitamin supplement (Sheep mixture, Norvite Supplements Ltd. ) was

22 given at 10-15 g day -1. Animals had free access to water at all times. W h e n hay was given alone, it was supplemented with urea. The experimental design was based upon the first three rows of a 12 X 12 Latin square. Each of the four cereals was given at 0, 33 and 67% of the diet. All diets were given at an estimated maintenance level of ME intake. Each experimental period lasted 21 days, faeces and urine being collected during 10 of the last 11 days. Faeces were collected by the bag and harness method and urine was collected by chutes suspended beneath the crates. Faeces were collected daily, weighed and frozen at - 15 ° C. The total faecal output was thawed, bulked and mixed prior to sampling. Urine was preserved at a p H of 2-4 with 4 M H2S04, collected daily and weighed. A 5% aliquot was taken each day, bulked and frozen to await analysis. The digestibility of the cereals in the mixed diets were derived using the equation: a~--

Y-bp 1-p

where a and b are the coefficients of digestibility for the cereal and roughage, respectively, V is the digestibility of the mixed ration and p the proportion of roughage.

The pig trial The trial was conducted in two periods and involved two groups of 16 Landrace × Large-white gilts; their initial mean live weight was 38 kg. The gilts were held in crates to allow for collection of faeces and urine and were fitted with bladder catheters (14-gauge 10-ml Foley catheters) 48 h before the measurement period to enable faeces and urine to be separated. Feed was given in two 750-g portions each day with 2 1 water. Residues and spilt feed were dried and weighed each day or when they appeared. Within each experimental period, four animals were randomly allocated to one of four treatments. In period I, the four cereals plus minerals and vitamins comprised the treatments. In Period II, the cereals were supplemented with white-fish meal ( W F M ) , soya-bean meal (SBM) and synthetic lysine to give rations containing similar and adequate levels of essential amino acids (see Table I). Each experimental period lasted 21 days, faeces and urine being collected for the last 10 days. Faeces were collected into plastic bins beneath the crates. Daily accumulations were removed, bulked, mixed to a slurry with water and acidified with 4 M H2SO4. At the end of a collection period, total faecal output plus water and acid was weighed and sampled. Urine was collected under acid (4 M H2SO4) into plastic bottles. T h e p H was maintained below 3.

23 TABLE I Ration formulations for the pig trial (g kg- 1 air-dry feed) Period I An cereals

Cereal White-fish meal Soya-bean meal

Synthetic lysine Vitamin supplement

Limestone Dicalcium phosphate Salt

980 0 0 0 9.7 5.9 1.8 1.6

Period II

Wheat

PBI 121

Lasko

Aquarius

796.6 62.9 128.7 2.0

836.8 44.0 100.0 3.6

900.0 41.2 31.0 4.3

892.0 57.2 35.2 2.4

2.5 6.6 0 0.6

2.5 7.9 4.2 1.1

2.5 9.3 9.8 1.9

2.5 6.5 2.8 1.3

The apparent ME poultry trial Birds were chosen from a group of 3-week-old Ross broiler chicks, each weighing 600-700 g. They were held in groups of four, in cages (60 X 60 X 30 cm). Polythene sheets were placed beneath the floors for the collection of excreta. The cages were in three tiers, with an equal number of replicates from each treatment in each tier. Water was available at all times, being dispensed by nipple drinkers. The ambient temperature of the house was 21°C and the lighting period was for 1 h in 24. Each replicate of four birds was allocated 5 kg feed for the experimental period. Feed troughs were filled with a proportion of this at the beginning of the balance trial and replenished daily. Feed intake was determined from the a m o u n t of unused feed at the end of the balance period. The experiment was a randomized block design with seven treatments and three blocks (representing the tiers of cages). Two replicates from each treatment were assigned to each block. The treatments were designed so that the cereals could be evaluated in diets in which either the cereal content was equal, but the protein content varied ( "equal cereal" ) or where the cereal content differed, but the protein content was equal ("iso-nitrogenous") (see Table II). After an adaptation period had been completed, there was an experimental period of 15 days, excreta being collected for the last 10 days. Excreta were removed from sheets on alternate days, weighed and sampled.

Assay of TME for poultry This experiment was conducted in the T M E unit of the Poultry Research Centre, Roslin. The technique was based on that developed by Sibbald (1983). The birds were from a flock regularly used for T M E determinations. They were 25-week-old, dubbed Warren cockerels weighing 3-3.5 kg. The experiment was of a randomized block design with five treatments (the four cereals and a aeg-

24 TABLE

II

Ration formulations for the apparent ME poultry trial (g kg -~ air-dry feed) Iso-nitrogenous Equal cereal

Cereal Soya-bean meal Mineral and vitamin mixture

Norman

PBI 121

Aquarius

Norman

PB1121

Aquarius

Lasko

850 145

850 145

850 145

850 145

750 245

700 295

800 195

5

5

5

5

5

5

5

ative control of glucose to calculate endogenous energy losses) and six birds per treatment. The birds were housed individually in mesh metabolism cages and trays were placed beneath for the collection of excreta. The experiment lasted 5 days, as follows. Day 1. The birds were put into cages and food was withheld. In the afternoon, birds were given 50 ml water plus 25 ml glucose in a tube (to reduce losses of endogenous energy in N compounds arising from catabolism). Day 2. As for Day 1. Day 3. Birds were weighed and fed by tube with exactly 50 g of cereal or glucose. After feeding, a collection tray was placed beneath the cage. Day 4. The birds received 50 ml water via a tube. Day 5. Excreta were removed exactly 48 h after feeding and weighed and sampled for freeze drying. The birds were re-weighed and returned to resting pens. RESULTS

Chemical composition of the cereals The chemical composition of the cereals is given in Table III. The DM content ranged from 850 to 896 g kg -1 fresh matter and organic matter (OM) accounted for, on average, 978 g kg- 1 DM. The N content of the control, Norman wheat, was higher than that of the PBI 121, which was unusually low. In contrast, Aquarius and Lasko contained high levels of N, thus the range in N content of the triticale varieties was almost 2-fold. Within the CP, there was considerable variation in the lysine content between cereals. However, this variation was not related to protein content since Lasko had a relatively high lysine content. On a DM basis, Norman wheat had a lower lysine content (3.65 g kg -~ DM) than any of the triticale varieties (3.96, 4.19 and 6.07 g kg -1 DM for PBI 121, Aquarius and Lasko, respectively). There was less variation

25 TABLE III The chemical composition of the cereals (g kg -1DM unless otherwise stated) Wheat Norman Dry matter (g kg -~ fresh) Organic matter Nitrogen Crude protein (Nx6.25) Lysine (gkg -1 CP) Threonine (g kg -1 CP) Cystine plus methionine (gkg -~ CP) Acid detergent fibre Neutral detergent fibre Ether extract Gross energy (MJ kg- DM)

Triticale PBI 121

Aquarius

Lasko

850 978 22.4 140 26.1 31.4

866 980 17.3 108 36.7 34.7

867 977 27.0 169 24.3 28.2

896 977 30.6 192 31.6 33.6

29.0 32.9 108 21.5 17.78

30.4 32.9 157 37.8 17.67

29.7 37.0 155 22.6 17.99

28.8 35.1 161 26.0 18.02

between the varieties in the concentration of threonine and the sulphur-containing amino acids, but there was a tendency for Aquarius to have lower concentrations than other varieties. Lasko was a good source of essential amino acids owing to the high protein content. The ADF ~nd NDF concentrations were lower in wheat than in the triticale varieties; within the latter, concentrations were similar. The ether extract concentration was higher for the PBI 121 than for any other cereal. Gross energy was similar for all varieties, but tended to be higher in Aquarius and Lasko.

The sheep trial The chemical composition of the diets given to sheep reflected the relative proportions of hay and cereal in the rations. The OM concentration was similar for all diets (942 g kg -1 D M ) . The diet of hay alone contained urea and consequently had a higher N content (21.4 g k g - 1DM) than the original material (15.0 g kg -1 D M ) . As the proportion of cereal in the diet increased, the concentration of N varied according to the N content of the cereal. GE concentration was little affected by cereal type, although as the level of cereal inclusion increased so too did gross energy content: from 17.13 M J kg -~ DM at zero cereal to a mean of 17.54 M J kg -1 DM at 67% cereal inclusion. The digestibility coefficients for the cereals obtained by simultaneous equations are given in Table IV. There were no significant differences between the cereals in the digestibility of DM, OM, ADF or gross energy. For N, however,

26 T A B L E IV The predictedcoefficientsof digestibilityfor the cerealcomponents of the sheep dietscalculatedby simultaneous equations Wheat Norman Dry matter Organic matter Nitrogen ADF

Triticale

0.896 0.905 0.829 0.502

PBI 121

Aquarius

Lasko

0.873 0.869 0.736 0.508

0.899 0.893 0.865 0.544

0.903 0.920 0.891 0.565

SEM (error d f = 25 )

Level of significance

0.0107 0.0205 0.0201 0.0311

NS NS "" NS

digestibility was significantly lower for PBI 121 than for Lasko or Aquarius (P<0.001). Digestible and metabolizable energy values of the cereals are given in Table V. As GE values and digestibility coefficients were similar for all cereals, there were no significant differences between treatments in DE value. Methane energy losses were predicted from the digestibility of energy, according to the equations of Blaxter and Clapperton (1965). Urinary energy losses were based upon the N content of the urine using relationships from the Feedingstuffs Evaluation Unit, Rowett Research Institute, Aberdeen (P.J.S. Dewey, personal communication, 1985). UE =

0.0527N- 0.0334

where U E is urinary energy in kJ k g - 1 fresh urine and N in g k g - 1 fresh urine. Methane energy losses were calculated to be similar for all treatments. Urinary energy losses, in contrast, were significantly lower for sheep given PBI 121 ( P < 0.05 ) as a consequence of lower urinary N losses. The ME values for TABLE V Digestible energy and predicted metabolizable energy values for the cereal components of the sheep diets Wheat Norman Gross energy ( M J kg -1 DM) Digestibility of energy Digestible energy ( M J kg - 1 D M ) Methane energy/GE Urinary energy/GE MetabolizabUity of energy Metabolizable energy ( M J kg -1 DM)

Triticale

SEM (error d f = 25 )

Level of significance

PBI 121

Aquarius

Lasko

17.78 0.886

17.67 0.880

17.99 0.897

18.02 0.904

0.0136

NS

15.77 0.098 0.0603 0.724

15.54 0.109 0.0312 0.754

16.15 0.101 0.0730 0.725

16.30 0.102 0.0611 0.740

0.218 0:00488 0.00899 0.0123

NS NS NS

12.87

13.38

13.07

13.32

0.2034

NS

27 T A B L E VI The chemicalcompositionof the pig diets (g kg-I D M unlessotherwisestated) Period I (cereals alone)

Period II (cereals plus protein supplement )

Wheat

Wheat

Tritieale

Norman OM 970 N 20.6 CP ( N × 6 . 2 5 ) 129 ADF 27.7 NDF 106 EE 21.1 GE ( M J kg -1 D M ) 17.97 Lysine (g kg -1 CP) 25.6 Threonine (g kg -~ CP) 30.8 Methionine + cystine ( g k g -~ CP) 28.4 Ca 5.21 P 4.72 Mg 1.54 Na 1.23 K 3.63

Triticale

Norman PBI 121

Aquarius

Lasko

968 16.0 100 41.7 154 37.1

970 26.4 165 34.4 152 22.2

967 28.9 181 36.5 158 25.5

964 31.8 199 53.2 163 50.1

PBI 121

Aquarius Lasko

954 26.1 163 55.8 251 37.8

961 33.4 209 41.1 234 25.1

957 33.9 212 42.2 283 23.8

17.32

17.81

17.92

18.74

18.15

18.39

18.42

36.0

24.3

31.0

44.8

59.5

41.1

43.2

34.0

27.6

32.9

35.2

35.4

32.6

36.1

31.0 3.44 5.68 1.88 0.87 6.34

29.7 3.63 5.67 1.69 0.83 5.18

28.2 3.90 5.92 1.68 0.79 6.56

25.5 7.63 4.81 1.25 0.69 6.24

27.5 9.05 6.80 1.46 1.17 7.68

29.5 7.77 6.83 1.39 1.30 6.37

30.8 10.7 8.29 1.29 1.41 7.30

the four cereals were not significantly different from each other, the mean value being 13.16 MJ kg -1 DM.

The pig trial The chemical composition of the cereals has been given previously and the composition of the diets in Period I was similar to that of the cereals alone. In Period II (see Table VI), supplementation increased the N content to > 3 0 g kg -1 DM (187 g CP kg -1 DM) in the Norman, Lasko and Aquarius treatments, but to less than this in the PBI 121 treatment (26.08 g kg -1 DM or 163 g CP kg-~ DM). Supplementation tended to increase the concentrations of ADF, NDF and GE, but had little effect on ether extract. In Period I, the concentration of essential amino acids was low relative to the requirements of growing pigs. In Period II, supplementation increased their concentration, but at the level of feeding employed, the intake of essential amino acids was still marginally deficient for this class of pig (Agricultural Research Council, 1981). The deficiency was greatest for lysine in Norman and Aquarius, which provided only 64% of the requirement. The treatments were adequate in most minerals except

28 TABLE VII Pig trial: the digestibility coefficients and DE values for the diets given in Periods I and II

Dry matter Organic matter Nitrogen ADF NDF Gross Energy DE (MJ kg -1 DM)

Period I (cereals alone)

Period II (cereals plus protein supplement)

Wheat Norman

Wheat Norman

0.896 0.909 0.860 0.286 0.618 0.890 16.03

Triticale PBI 121

Aquarius

Lasko

0.850 0.867 0.728 0.359 0.605 0.841 14.56

0.874 0.888 0.851 0.319 0.661 0.866 15.43

0.856 0.874 0.846 0.283 0.646 0.856 15.34

0.883 0.899 0.856 0.575 0.748 0.886 16.60

Triticale PBI 121

Aquarius

Lasko

0.842 0.861 0.723 0.492 0.768 0.838 15.21

0.858 0.874 0.852 0.375 0.771 0.856 15.74

0.848 0.874 0.834 0.379 0.819 0.845 15.57

SEM and level of significance (error d r = 2 4 )

Dry matter Organic matter Nitrogen ADF NDF Gross Energy DE (MJ kg - 1 D M )

Treatment

Period

Treatment × period

0.00363 "'° 0.00324 "°° 0.0104 "" 0.0123 "'" 0.0724 "" 0.00386 °'. 0.0668 ""

0.00356 *° 0.00229NS 0.00733NS 0.00894 *'° 0.00512"0.00273NS 0.0476 **"

0.00513NS 0.00458NS 0.00947NS 0.0179 "*" 0.0102 ° 0.00546NS 0.0946 NS

phosphorus (Norman, Periods I and II, PBI 121, Lasko, Aquarius, Period I) and sodium (Norman, Period II, Aquarius, Period I). The apparent digestibility coefficients and DE values for the treatments in Periods I and II are given in Table VII. The results from both periods combined will be considered first. For DM, OM and GE, digestibility was significantly higher for wheat t h a n for the three varieties of triticale ( P < 0.01 ), the difference being ~ 0.03 units. The digestibility of N in Norman wheat was similar to that in Aquarius and Lasko, but the N digestibility in PBI 121 was significantly lower than in all other treatments ( P < 0.001 ). The digestibility of ADF was significantly higher for N o r m a n and PBI 121 than for Aquarius and Lasko ( P < 0.01 ), but the reverse was true for NDF digestibility (P < 0.05 ). There was a significant effect of period (i.e., raising the N content) on the digestibility of DM ( P < 0 . 0 1 ) , ADF and NDF ( P < 0 . 0 0 1 ) , with DM digestibility being slightly lower, but fibre digestibility being higher in Period II. The DE of wheat was significantly higher than that of the triticale varieties ( P < 0.01 ). The DE values obtained in Period II were significantly higher t h a n those of Period I ( P < 0.001), as GE contents tended to be higher in Period II (see Table VII).

29 TABLEVIII Thechemicalcompositionofthepoultrydietsin the apparent MEtrial (gkg-] DM) unlessotherwisestated) Iso-nitrogenous

Equal cereal

OM N CP ( N × 6 . 2 5 ) ADF NDF GE ( M J kg -z DM) Lysine (g k g - ' CP ) Threonine (g kg -] CP) Methionine + cysteine (g kg -1 CP)

Wheat

PBI 121

Aquarius

Wheat

PBI 121

Aquarius

Lasko

972 28.9 181 48.5 183 18.72 37.8

969 21.8 136 54.8 213 18.29 43.7

969 30.2 189 53.8 186 18.83 36.5

966 36.6 229 59.1 211 18.92 37.2

968 32.9 206 62.5 195 19.14 35.8

980 31.2 195 71.8 225 19.17 46.0

967 34.6 216 62.0 183 19:19 35.4

31.4

37.1

37.7

31.7

33.4

35.5

31.6

22.2

29.3

28.2

27.8

22.0

27.5

25.5

The apparent ME poultry trial The chemical composition of the diets is given in Table VIII. The OM concentration was similar for all treatments. Within the "equal cereal" diets, there was a 1.6-fold range in N concentration, but this was reduced to a 1.2-fold range in the "iso-nitrogenous" diets. The ADF concentration tended to increase as the cereal content of the diet declined. Variation in the NDF fraction, however, was not related to the level of cereal inclusion and tended to be greatest in the Lasko and PBI 121 treatments. Within groups, there was only small variation in energy value, but this was higher by 0.55 MJ kg -1 DM for the "iso-nitrogenous" group than for the "equal cereal" group. The composition of the crude protein varied between the treatments. In both treatments containing PB1121, lysine constituted on average 44.8 g kg- 1CP, but in other treatments the mean lysine content was lower, at 36.5 g kg-1 CP. Threonine concentration ranged from 31.4 to 37.7 g k g - ~CP and the sulphur amino acids accounted for 22.0-29.3 g kg- 1 CP. The concentration of these amino acids expressed on a DM basis tended to be lower in the wheat and PBI 121 treatments of the "equal cereal" group than in other treatments. Apparent ME values for the seven treatments for chicks are given in Table IX. As in the pig trial, GE content was higher for the diets containing higher levels of supplement. Further, there were significant differences in metabolizability between treatments ( P < 0.001). Metabolizability was ~ 0.04 units higher for diets containing wheat than for diets containing either PBI 121 or Aquarius. The metabolizability of Lasko was lower still, being some 0.07 units lower than the other varieties of triticale. Thus there were significant differences in ME value between wheat and triticale ( P < 0.001 ) and Lasko and the

30 TABLE IX The metabolizability coefficients and ME of the poultry diets ( M J k g - l DM) Iso-nitrogenous Equal cereal Wheat Metabolizability Dry matter Organic matter Nitrogen NDF Apparent ME Gross energy Metabolizability of energy ( M E G E ) ME ME corrected to zero N retention True ME Uncorrected Corrected

0.751 0.735 0.435 0.569

Wheat

PBI 121 Aquarius Lasko

0.730 0.730 0.298 0.536

0.710 0.708 0.333 0.482

0.645 0.638 0.320 0.577

18.72

18.29

18.83

18.92

0.749 14.02

0.719 13.14

0.710 13.38

13.65

12.92

15.62 15.21

14.21 14.00

PBI 121 Aquarius SEM and level of significance (error d f = 33)"

0.733 0,733 0.415 0.549

19.14

0.687 0.619 0.331 0.535

0.695 0.691 0.349 0.472

0.00707"'" 0.00910 .°. 0.0226 "" 0.0159 ""

19.17

19.19

0.638 0.739 12.08 14.14

0.695 13.32

0.700 13.44

0.00755 °'" 0.0960 ""

13.07

11.82

13.75

13.06

13.18

0.1703 "'"

15.02 14.48

14.64 14.20

-

-

0.1236 "'" 0.1037 "'"

"20 for true ME.

other varieties ( P < 0.001 ). The values were also corrected to zero N retention by using the relationship proposed by Davidson et al. (1978). Correcting for N balance tended to reduce ME content, but did not affect the ranking of cereals in terms of their ME value. The ME value (uncorrected or corrected) of rations containing the same cereal was not significantly influenced by changing the proportion of cereal in the diet.

Assay o[ TME for poultry The T M E values of the four cereals, uncorrected or corrected to zero N retention, are included in Table IX. The TME of wheat was significantly higher than that of the three varieties of triticale. Within the triticale varieties, there were no significant differences in TME, but Aquarius had the highest and PBI 121 the lowest. Thus the ranking differed between the classical ME and T M E results. DISCUSSION

Interest in triticale as a cereal for livestock can be attributed to its reputedly high protein content (Hulse and Laing, 1974). However, the chemical com-

31

position of the triticale used in these trials illustrates that there can be large differences between varieties. The range in CP content was from 108 to 192 g kg-1 DM and similar wide ranges have been reported elsewhere (Villegas et al., 1970; Farrell et al., 1983). Clearly, triticale need not necessarily have a protein content higher than that of other cereals. The variability in protein may be related to growing conditions or to inherent varietal differences. Ears of triticale normally contain more fertilized seed than other cereals (Vermorel and Bernard, 1979) and in poor growing conditions, grain fill is restricted; this results in shrivelled grain having a smaller proportion of starchy endosperm and consequently a higher protein content. This appears to have been the cause of the high protein content in the Lasko, as shrivelled and filled grains had protein contents of 216 and 158 g kg -1 DM, respectively. The sample of Aquarius, on the other hand, was not shrivelled and the high protein content may have been characteristic of the variety (Hulse and Laing, 1974). The three varieties of triticale also showed considerable variation in lysine content, this being only 24 g kg- 1 CP for Aquarius, but 37 g kg -1 CP for PBI 121. It is likely that for well-filled grains (Aquarius and PBI 121 ), the lysine content of CP is inversely proportional to the protein content. This has been demonstrated by Farrell et al. (1983). However, in shrivelled samples (Lasko), both CP and lysine concentrations were high. This may be due to a higher proportion of albumins and globulins, relatively rich in lysine and associated with the outer layers of the grain and a lower proportion of endosperm proteins, a relatively poor source of lysine (Vermorel and Bernard, 1979 ). All three triticale varieties, but particularly the Lasko, were a better source of lysine than the Norman wheat. Similar observations have been made in previous comparisons between triticale and wheat or other cereals (Sell et al., 1962; McNab and Shannon, 1975; Johnson and Driscoll, 1984). Even in PBI 121, which had a lower protein content than Norman, the lysine content was 1.1 times greater. The fibre concentration of the triticale varieties was 1.5 times greater than that of the wheat. This supports the view that higher protein levels in triticale than in wheat are attributable to smaller grain size. In sheep, no differences were observed between the cereals in digestibility of DM, OM, ADF or energy. Although no experiments could be found in the literature for which the design allowed the determination of cereal digestibility in mixed rations, the results suggested that the digestibility of triticale was similar to that of other cereals (Sherrod, 1976; Felix, 1980; Felix et al., 1985). The estimated ME value for sheep of the Norman wheat was 12.87 MJ kg -1 DM, considerably below published values of 14.00 (Ministry of Agriculture Fisheries and Food, 1975), or 13.5 MJ kg-1 DM (Rowett Research Institute, 1978). Thus, although the ME value of triticale in the current trial was slightly higher than that of wheat (13.25 MJ kg -1 DM), it was still lower than the published values for wheat. For the determination of the ME value of a cereal

32 in a mixed diet by simultaneous equations or regression, it is assumed that there is a simple additive relationship between the ME values of the diet and its components. There is, however, the possibility of an interaction between the cereal and roughage components of the ration. Such associative effects would tend to reduce the ME value of the mixed rations and if the ME value of the hay is assumed to be unaffected, the predicted ME content of the cereal would be reduced. For pigs, in contrast to sheep, the DE value of triticale was slightly, but significantly lower than that of wheat. This was possibly because of the higher fibre concentration of the triticale varieties. However, it was observed that when cereals were given without protein supplementation, fibre digestibility was higher for triticale t h a n wheat. This was not apparent when adequate protein was supplied in the diet and there was a marked increase in fibre digestibility for all cereals. Evidently, the pig's ability to digest fibre was being depressed by the low level of protein in the diet, however, since ADF accounted for only between 2 and 4% of the diet, there was no significant effect of protein supplementation on digestibility of OM or energy. The mean DE content of the three triticale varieties was 15.31 MJ kg-1 DM, which was similar to the value obtained by Cornejo et al., (1973), but slightly below those found by other workers (Erickson et al., 1979; King, 1980; FarreU et al., 1983) which were ~ 16 MJ kg -1 DM. The pig diets were either composed almost entirely of cereal (i.e., supplemented only with minerals and vitamins) or balanced for protein and amino acid requirements. In the unbalanced rations, Lasko was a better source of lysine and threonine than other cereals and supplied 43 and 78% of requirements, respectively (Agricultural Research Council, 1981 ). This was markedly better t h a n N o r m a n wheat which supplied only 25 and 48% of lysine and threonine requirements, respectively. T h u s in the second period, in which lysine levels were equilibrated somewhat below requirements (0.57 rather than 0.84 g lysine MJ-~ D E ) , there was a 50% saving in the a m o u n t of protein concentrate used. If diets had been formulated to meet requirements, there would still have been a 25% saving in protein concentrate. The trial showed that altering the level of cereal inclusion from 98 to between 80 and 90% of the ration did not affect digestibility of OM, N or energy. Thus, the inclusion of triticale at high levels to replace a proportion of protein concentrate would not affect DE. It is concluded that the triticale varieties studied were of slightly lower DE content t h a n the wheat, but supplied a higher proportion of essential amino acids. Without data on voluntary intake, their value in pig rations could not be wholly ascertained. In the determination of apparent ME content made with chicks, level of cereal inclusion had no effect on metabolizability, consequently, it can be assumed that protein intake did not influence ME. As in the pig trial, the ME content of triticale was less t h a n that of wheat. The difference, of just over 0.5

33 MJ kg -1 DM for Aquarius and P B I 121, was not large. Salmon (1984) found a difference of 0.30 MJ kg -1 DM between wheat and triticale in T M E value. The mean ME value for triticale taken from four experiments in the literature was 14.26 MJ kg-1 DM (Shimada and Cline, 1974; Yaqoob and Netke, 1975; McNab and Shannon, 1975; Rao et al., 1976) which was ~ 1 MJ kg -1 DM higher than that found for Aquarius and PBI 121. The increased proportion of nutrients voided in excreta of birds given Lasko was probably due mainly to starch, since there were no increases in losses of N or fibre. This observation suggests that trypsin inhibitors, implicated in earlier work (Sell et al., 1962), were not responsible in this instance. It is possible that factors known to depress performance in chicks given rye (Antoniou and Marquardt, 1981) were present in the Lasko triticale, but the presence of these compounds in triticale has yet to be established. Alternatively, the young chicks may have been unable to utilize the nutrients in Lasko owing to an underdeveloped gizzard. Certainly, the Lasko grain was difficult to grind properly since the husk separated from the endosperm. In the T M E trial, older birds were used and energy utilization was similar for all triticale varieties. T h u s the factor responsible for depressing ME in chicks was not apparent in older birds. This may have been a consequence of better grinding or of physiological adaptation to a possible anti-nutritional compound. In all other respects, the two poultry trials gave similar results. The T M E values were ~ 1.1 times greater t h a n classical ME values, but this observation is in keeping with the results of others (e.g., Rao et al., 1976; Halvorsen et al., 1983). The results of these trials indicate that whilst the higher fibre content of triticale may marginally affect DE or ME values in non-ruminants, the higher protein concentration found in some varieties should be a nutritional advantage to all classes of livestock. Further, the favourable balance of essential amino acids increases its value in pig and poultry diets. ACKNOWLEDGEMENTS The authors wish to acknowledge the Ministry of Agriculture and Fisheries and Food for funding the project, the Plant Breeding Institute for supplying triticale, Mr. W. Michie and his staff for providing facilities for poultry metabolism trials, the Poultry Research Centre for providing facilities for the determination of true ME, the Rowett Research Institute for providing facilities for the pig metabolism trial and Dr. J.H. Topps and the staff of the School's Agricultural Chemistry and Biochemistry Division (especially Dr. N.H. Stephen) for chemical analyses.

34 REFERENCES Agricultural Research Council, 1981. The Nutrient Requirements of Pigs. Commonwealth AgriculturalBureaux, Farnham Royal, Slough. Antoniou, T. and Marquardt, R.R., 1981. Influence of rye pentosans on the growth of chicks. Poult. Sci.,60: 1898-1904. Blaxter, K.L. and Clapperton, J.L., 1965. Prediction of the amount of methane produced by ruminants. Br. J. Nutr., 19: 511-522. Cornejo, S.,Potocnjak, J.,Holmes, J.H.G. and Robinson, D.W., 1973. Comparative nutritivevalue of triticalefor swine. J. Anita. Sci.,36: 87-89. Davidson, J., Banfield, C.G., Duguid, J.G.W. and Leitch, E.G., 1978. The measurement of metabolisable energy in samples of oats, barley and wheat using chicks. J. Sci. Food Agric., 29: 339-344. Dinusson, W.E., 1971. Triticale,wheat and barley as livestock feeds. Proceedings 32 Minnesota Nutrition Conference, University of Minnesota. Erickson, J.P.,Miller,E.R., Elliott,F.C., Ku, P.K. and UUrey, D.E., 1979. Nutritional evaluation of triticalein swine starterand grower diets.J. Anita. Sci.,48: 547-553. Farrell,D.J., Chan, C., McCrae, F. and McKensie, R.J., 1983. A nutritionalevaluation of triticale with pigs. Anita. Feed. Sci. Technol., 9: 49-62. Felix,A., 1980. Comparative nutrient digestibilityand nitrogen retention in ewes fed whole grains of triticale,wheat and corn. J. Anita. Sci.,51 (supplement 1 ) 358 (abstract). Felix,A., Hill,R.A. and Winchester, W., 1985. A note on nutrient digestibilityand nitrogen retention in ewes fed whole grains of triticale, wheat and maize. Anita. Prod., 40: 363-365. Gregory, R.S., 1979. Hexaploid triticale. Annual Report of the Plant Breeding Institute, Cambridge, for 1978, pp. 71-72. Goering, H.K. and Van Soest, P.J., 1970. Agricultural Handbook Number 379, Agricultural Research Service, USDA. Halvorsen, J.C., Shehata, M.A. and Waibel, P.E., 1983. White lupins and triticale as feedstuffs in diets for turkeys. Poult. Sci., 62: 1038-1044. Hulse, J.H. and Laing, J.M., 1974. Nutritive value of triticale protein. International Development Research Centre, Ottawa. Johnson, R.J. and Driscoll, C.J., 1984. The use of a total protein efficiency technique to evaluate the nutritional quality of triticale relative to wheat and rye for broiler chicks. Nutr. Rep. Int., 39: 233-242. Jordan, R.M. and Hanks, H.E., 1972. Finishing lambs with triticale, barley or corn. Feedstuffs, 44: 30. King, R.H., 1980. The nutritive value of triticale for growing pigs. Proc. Aust. Soc. Anim. Prod., 13: 381-384. McNab, J.M. and Shannon, D.W.F., 1975. The nutritive value of triticale and rye for the laying hen. Br. Poult. Sci., 16: 9-15. National Research Council, 1982. United States-Canadian tables of feed composition. Third Revision. National Academy Press, Washington, DC. Rao, D.R., Johnson, W.M. and Sunki, G.R., 1976. Replacement of maize by triticale in broiler diets. Br. Poult. Sci., 17: 269-274. Reddy, N.V., Chen, M.L. and Rao, D.R. (1975). Replacement value of triticale for corn and wheat in beef finishing rations. J. Anita, Sci., 40: 940-944. Rowett Research Institute, 1978. Feedingstuffs Evaluation Unit, Second Report. Salmon, R.E., 1984. True metabolisable energy and amino acid composition of wheat and triticale and their comparative performance in turkey starter diets. Poult. Sci., 63: 1664-1666. Sell, J.L., Hodgson, G.C. and Shebeski, L.H., 1962. Triticale as a potential component of chick rations. Can. J. Anita. Sci., 42: 158-166.

35 Sherrod, L.B., 1976. Triticale as a feed grain for ruminants. In: S.P. Yang (Editor), First International Triticale Symposium, El Batan, Mexico. ISCALS Publication 76-1, pp. 131-141. Shimada, A. and Cline, T.R., 1974. A comparison of in vivo and in vitro metabolisable energy of triticale for the chick, rat and pig. J. Anim. Sci., 38: 1257-1260. Shimada, A., Cline, T.R. and Rogler, I.C., 1974. Nutritive value of triticale for the non-ruminant. J. Anita. Sci., 38: 935-940. Sibbald, I.R., 1983. The TME system of feed evaluation. Agriculture Canada, Animal Research Centre. Vermorel, M. and Bernard, M., 1979. Intgr~t agronomique et nutritional du triticale. Bull. Tec. Cent. Res. Zootech. Vet. Theix, 36: 31-42. Villegas, E., McDonald, C.E. and Gillies, K.A., 1970. Variability in the lysine content of wheat, rye and triticale varieties. Cereal Chem., 47: 746-757. Yaqoob, M.M. and Netke, S.P., 1975. Studies on the incorporation of triticale in diets for growing pigs. Br. Poult. Sci., 16: 45-54.