Nutritional and growth studies with pea-crop meals and peas for growing—Finishing pigs

Animal Feed Science and Technololty, 16 (1986) 119--128

119

Elsevier Science Publishers B.V., Amsterd*m -- Printed in The Netherlands

NUTRITIONAL AND GROWTH STUDIES WITH PEA-CROP MEALS AND PEAS FOR GROWINCr-FINISHING PIGS

S. LUND and J. H~kKANSSON

Swedish University of Agricultural Sciences, Department of Animal Nutrition and Management, Funbo-L6vsta Research Station, 755 90 Uppsala (Sweden) (Received 24 October 1985; accepted for publication 20 May 1986) ABSTRACT Lund, S. and H~kansson, J., 1986. Nutritional and growth studies with pea-crop meals and peas for growing--finishing pigs. Anita. Feed Sci. Technol., 16: 119--128. Two pea~rop meals consisting of the whole plant harvested at two stages, dried and ground (PCM 1 and PCM 2) and peas (P. sativum) harvested from the same field, were evaluated in metabolic and growth experiments with growing--finishing pigs. The mean contents of metabolizable energy (ME) in PCM 1, PCM 2 and peas were 10.1, 9.0 and 15.5. MJ per kg DM, respectively. Digestion coefficients for organic matter, crude protein and N-free extract fractions in the peas were 90, 86 and 96%, respectively. A growth experiment with 96 growing-finishing pigs at two lysine levels (0.82 and 0.92% of DM) was performed with diets containing 18% PCM 1, PCM 2.or peas. Each treatment included 3 groups made up of 2 castrates and 2 female pigs fed individually. No significant differences were found in daily gain between the pigs given the diets containing the peas or the control diets based on soya bean meal. A higher daily gain was obtained for the pigs given the diets containing PCM 2, than with those given the diets containing PCM 1, on both lysine levels. These results are probably due to the fact that the PCM 2-material contained a larger proportion of peas than the PCM 1-material. Results from the growth experiment indicate that PCM harvested at a later stage (PCM 2) may be included at a level of up to 18% in the diets for growing--finishing pigs.

INTRODUCTION

A higher rate of daily gain (800 g) was obtained in studies with growing-finishing pigs given a diet containing a low DE level, 11.9 MJ per kg (Petersson et al., 1981). In experiments with growing pigs (MalmlSf and H~kansson, 1984) increasing the fibre level by adding straw meal to a barley and fish meal diet, and giving the same amount of protein in relation to metabolic live weight, improved daily nitrogen retention. These results have increased the interest in using whole crop feeds in pig feeding. The nutritive value of pea~rop meal (PCM) harvested from two cultivars of peas, Simo and Lotta, and artificially dried was determined in growing pigs by Lund et al. (1981). The ME content was 10.7 and 9.7 MJ per kg DM, respectively. The digestibility of crude protein and organic matter was also

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© 1986 Elsevier Science Publishers B.V.

120 higher in PCM from Simo (68 and 68%, respectively) than in PCM from Lotta (56 and 61%, respectively). Studies of the nutritive value of grass meal, clover meal and pea-crop meal (cultivar Simo) for growing pigs (H~ikansson and MalmlSf, 1984) included the digestibility of carbohydrate fractions, which were less digested in the clover and pea-crop meals owing to a higher degree of lignification. The ME content of PCM determined in metabolic experiments was 10.2 MJ per kg DM. Rundgren (1983) found a lower digestibility of organic matter (65%) and crude protein (56%) in whole crop pea silage for growing pigs weighing around 33 kg, compared with 76 and 76%, respectively, for growing---finishing pigs weighing around 72 kg, and 76 and 75%, respectively, for pregnant sows. The present work was performed in order to study the nutritive value of PCM harvested at two stages of growth and to compare PCM with peas harvested from the same field. The studies also included growth experiments with growing--finishing pigs. MATERIALS AND METHODS

Experimental feeds A stand of P. sativum (cv Simo) grown in the Uppsala region was harvested on two occasions (28 July 1982 and 6 August 1982, 3 and 4 weeks after the beginning of flowering) and dried to give PCM 1 and 2, respectively. The drying of the PCM-crops was performed by 5 days of field drying to a DM content of approximately 60%, followed by artificial drying at 30°C for 5 days to a DM content of 86%. They were then ground in a hammer mill with a 3-ram screen. The final harvest of the pea crop from the same field was undertaken on 28 August 1982.

Digestibility experiments Animals

Nine castrated male pigs (Swedish Landrace × Swedish Yorkshire) from four litters were used. The range of live weights of the pigs was 30--44, 36--55, 45--67 and 51--78 kg during periods 1, 2, 3 and 4, respectively.

Diets The composition of the basal diet (ingredients in per cent by weight) was as follows: barley, 42.0; wheat, 21.0; maize, 15.0; soya bean meal, 11.0; fish meal, 3.0; meat and bone meal, 2.0; animal fat, 2.0; calcium carbonate, 1.3; mono-calcium phosphate, 1.3; sodium chloride, 0.3; and vitamin and mineral mixture, 1.1. The diets used in the digestibility experiments (in per cent by weight) were (1) Basal diet (100) and (2)--{4), Basal diets (70) and PCM 1, PCM 2 or peas (30).

121 TABLE I Analysed chemical composition in per cent of DM of feeds and diets used in the digestibility trial Pea-crop meal

Organic matter Ash Crude protein Crude fat N-free extract Crude fibre NDF ADF Hemicellulose Cellulose Lignin Gross energy (MJ kg-' DM)

Peas

PCM 1

PCM 2

93.1 6.9 19.1 2.9 50.8 20.3 26.3 23.1 3.3 23.8 6.4 18.00

93.3 6.7 16.7 2.5 51.3 22.8 30.9 27.0 3.9 26.9 7.2 17.69

Amino acid composition (g per 16 g N) Lysine 6.2 7.0 Threonine 4.0 4.0 Methionine 1.3 1.1 Cysteine 1.2 1.4 Histidine 2.3 2.3 Arginine 9.2 9.5 Aspartic acid 13.0 11.0 Serine 5.0 5.0 Glutamic acid 13.4 15.2 Proline 9.6 4.4 Glycine 4.3 4.5 Alanine 4.8 4.4 Valine 4.3 4.8 Isoleucine 4.2 4.3 Leucine 6.9 7.1 Tyrosine 3.4 3.4 Phenylalanine 4.2 4.9

97.0 3.0 25.6 2.4 63.2 5.8 7.8 7.7 0.1 8.7 1.6 18.56

Diets 1

2

3

4

95.5 4.5 17.9 5.9 67.7 4.0 13.1 5.6 7.5 4.4 1.3 18.50

94.1 5.9 18.3 5.0 61.8 9.0 16.3 11.4 4.9 12.2 3.4 18.43

94.1 5.9 17.6 4.9 62.2 9.4 18.0 11.7 6.3 19.3 3.5 18.29

95.2 4.8 20.2 4.9 65.1 5.0 11.2 6.5 4.7 7.5 1.8 18.26

7.3 3.8 1.0 1.4 2.4 9.6 11.0 4.9 16.0 4.0 4.2 4.1 4.5 4.0 6.8 3.3 4.8

The chemical composition of the PCM-products, the peas and the diets, and their amino acid composition are given in Table I. Feed was given twice a day at 08 00 and 16 00 h, and water was given ad libitum. Feed allowance was based on live weight and was as follows:

Live weight (kg) kg feed day -1

30 1.28

40 1.54

50 1.82

60 2.08

70 2.34

80 2.58

Design Each diet was given to two pigs for four periods according to a replicated 4 X 4 Latin square design.

122

Experimental technique After a pre-coUection period of 7 days on each diet, faeces and urine were quantitatively collected during a 4
Chemical analyses The analytical methods are described by H~kansson and MalmlSf (1984). The calculated chemical composition of the experimental diets was used for the difference calculations, which were carried out to give the digestibility of the PCM and peas. No corrections for nitrogen retention have been made when calculating the DE and ME contents of the diets and experimental feeds. Energy was determined on 50 ml of freeze-dried urine with a Gallenkamp adiabatic calorimeter (CB-100). The amino acid analyses were done at the National Swedish Laboratory for Agricultural Chemistry, S750 07 Uppsala. The statistical analyses were performed by using the SAS programme (Barr et al., 1979). TABLE II The g~oss and chemical c o m p o s i t i o n o f the diets used in the growth trial

Ingredients (%) PCM 1 PCM 2

Peu Barley Wheat S o y a b e a n meal Fish meal

Calcium carbonate D/calcium phosphate S o d i u m chloride V i t a m i n s and minerals

Control diet

E x p e r i m e n t a l diets

Control diet

E x p e r i m e n t a l diets

5

6

7

8

9

I0

11

12

--

18.0 --57.7 10.0 8.0 3.5 0.3 1.2 0.3 1.0

-18.0 -57.7 10.0 8.0 3.5 0.8 1.2 0.3 1.0

--18.0 61.3 10.0 4.0 3.5 0.7 1.2 0.3 1.0

---75.3 10.0 8.0 3.5 0.7 1.2 0.3 1.0

18.0 --61.7 10.0 4.0 3.5 0.3 1.2 0.3 1.0

-18.0 -61.7 10.0 4.0 3.5 0.3 1.2 0.3 1.0

--18.0 65.3 10.0 -3.5 0.7 1.2 0.3 1.0

17.9 2.4 8.4

17.9 2.6

17.1 2.2 4.5

16.8 2.6 7.5

16.4 2.5 8.4

16.4 2.6 4.8

--71.3 10.0 12.0 3.5 0.7 1.2 0.3 1.0

Calculated chemical compolflt/on (% o f D M ) Crude protein 18.7 18.4 Crude fat 2.3 2.6 Crude fibre 4.6 7.6 Calcium 0.85 0.84 Phosphorus 0.70 0.68 Lyslne 0.92 0.92

0.81 0.68 0.92

4.6 0.83 0.69 0.92

0.83 0.69 0.82

0.82 0.67 0.82

0.80 0.67 0.82

0.82 0.68 0.82

Calculated ME c o n t e n t M J k g -~ D M

14.0

13.3

A n a l y s e d chemical c o m p o s i t i o n (% o f D M ) Crude p r o t e i n 18.8 17.8 Lyslne 0.94 0.89

13.0

14.1

13.9

13.3

13.0

14.1

17.4

17.6

18.6

16.3 0.85

16.0 0.82

16.9 0.84

1.02

0.91

0.83

123

Growth experiments Design The experimental diets, containing 18.0% PCM 1, PCM 2 or peas, were tested against a conventional diet at two lysine levels, 0.82 and 0.92% of DM (Table II). The contents of digestible lysine in relation to the ME contents were calculated to be the same in all diets for each lysine level (0.51 and 0.58 g per MJ, respectively). The low protein diets were included in the trial to accentuate possible differences in protein quality between the pea~rop meal and the peas.

Diets The gross and chemical composition of the diets is given in Table II. In the experimental diets 18.0% PCM replaced 13.6% barley, 4.0% soya bean meal and 0.4% calcium carbonate in the control diets for both lysine levels. In the other experimental diets 18.0% peas replaced 10.0% barley and 8.0% soya bean meal. Digestible crude protein has been calculated from the crude protein content of the feeds and digestion coefficients from feed composition tables (Eriksson et al., 1976). The ME contents of the diets are based on feed composition tables (Eriksson et al., 1976) while the results obtained in the digestibility experiment have been used for the experimental feeds.

Animals The experiment consisted of 8 treatments and 3 replicates, each replicate consisting of 2 castrates and 2 female pigs weighing around 22 kg at the start of the experiment.

Experimental technique The pigs were fed individually twice a day at 08 00 and 15 00 h and were given the same amount of ME daffy in relation to weight: Weight (kg)

MJ day -~

Weight (kg)

MJ day -1

25 30 35 40 45 50 55

13.3 16.2 19.1 21.9 24.3 26.1 27.9

60 65 70 75 80 85 90--100

29.6 31.2 32.4 33.1 33.6 34.1 34.6

The pigs were weighed every two weeks and weekly when any pig had reached 90 kg live weight. They were slaughtered on reaching 100 kg live weight.

124

Chemical analyses Dry matter and crude protein were analysed according to methods described by H~kansson and MalmlSf (1984). Basic amino acid analyses were done at the National Swedish Laboratory for Agricultural Chemistry, S750 07 Uppsala. Carcass evaluation After slaughter, the carcass was chilled overnight and measurements were made the following day. Half of the carcass was dissected according to the system used in the Swedish pig progeny testing scheme (Andersson, 1977). The percentage of meat in the carcass was estimated according to a m e t h o d developed by Andersson {1977) in which partial regression equations were based on measurements of the depth of side fat and thickness of the eye muscle at the last rib 8 cm from the middle of the back. Digestive tract After slaughter the stomach and caecum were removed and rinsed with water. Injuries and e m p t y weights of both organs were registered, and the total length and breadth of the e m p t y caecum was measured. Statistical analyses All data were analysed by the method of least squares {Barr et al., 1979). RESULTS

Digestibility experiment The nutritive value o f the diets Digestibility of organic matter, crude protein and N-free extract was significantly higher in Diets 1 and 4 compared with Diets 2 and 3 (Table liD. The highest digestion coefficients for all carbohydrate fractions were obtained for Diet 4, containing the peas. The highest contents of DE and ME were observed for Diet 4, followed by Diets 1, 2 and 3. As a percentage of DE, ME was 96.7, 96.0, 96.7 and 96.5 in Diets 1, 2, 3 and 4, respectively. The nutritive value of the experimental feeds Highest digestibility of all nutrients was found for the peas followed by PCM 1 and PCM 2 (Table IV). The lower digestibility of all nutrients in PCM 2 compared with PCM 1 is probably explained by the higher crude fibre content in PCM 2. The value for the digestibility of hemicellulose in peas is unreliable because of its very low level. As a percentage of DE, ME was 93.1, 95.6 and 95.7 in PCM 1, PCM 2 and in the peas, respectively.

125 TABLE III Digestion coefficients of the nutrients and the ME contents of the diets Diets 1 (Basal)

S.E.

No. of pigs Organic matter Crude protein Crude fat N-free extract Energy Crude fibre NDF ADF Hemicellulose Cellulose ME (MJ per kg DM)

7 85 a 81 a 66 a 91 a 83 a 33 a 45 a 22 a 66 a 17 a 14.8 a

0.9 1.1 1.7 0.5 0.6 1.7 1.5 1.9 2.8 1.7 0.11

2 ( P C M 1)

3 ( P C M 2)

4 (Peas)

~

S.E.

~

S.E.

£

S.E.

7 81 b 75 b 57 bc

0.9 I.I 1.7

8 78 c 73 b 56 b

0.8 1.0 1.5

7 87 a 83 a 62 ac

1.0 1.0 1.9

90 b 77 b 35 a 40 ab 32 bc 56 b 35 b 13.5 b

0.5 0.6 1.6 1.5 1.9 2.8 1.7 0.11

88 c 74 c 32 a 37 b 28 b 55 b 35 b 13.1 c

0.5 0.5 1.5 1.4 1.7 2.5 1.5 0.09

93 a 85 d 47 b 54 c 37 c 76 c 45 c 15.1 d

0.6 0.6 1.8 1.7 2.1 3.1 1.9 0.12

a--dMeans having different superscripts within each line differ significantly (P < 0.05). TABLE IV Apparent digestibility of nutrients in the experimental feeds and their contents of ME PCM 1

Organic matter Crude protein Crude fat N-free extract Energy Crude fibre NDF ADF Hemicellulose Cellulose ME (MJ per kg DM)

65 63 26 80 60 36 31 36 12 41 10.1

PCM 2

Peas

S.E.

~

S.E.

~

S.E.

1.5 3.4 6.5 1.8 1.9 2.0 2.8 2.8 18.3 3.3 0.22

59 52 16 77 53 31 28 32 14 41 9.0

1.3 2.7 6.3 0.7 2.0 2.1 2.4 2.8 11.7 2.7 0.34

90 86 38 96 88 66 76 62 132 79 15.5

1.9 2.0 13.6 1.2 2.1 10.2 16.0 10.0 61.8 3.5 0.40

Growth experiments N o s i g n i f i c a n t d i f f e r e n c e s i n daffy g a i n w e r e f o u n d b e t w e e n pigs g i v e n d i e t s c o n t a i n i n g d i f f e r e n t l y s i n e levels ( T a b l e V). T h e pigs g i v e n D i e t s 8 a n d 12, c o n t a i n i n g t h e p e a s , h a d t h e h i g h e s t r a t e o f g a i n f o r b o t h l y s i n e levels, b u t n o s i g n i f i c a n t d i f f e r e n c e s w e r e f o u n d i n r e l a t i o n t o t h e c o n t r o l s . T h e pigs g i v e n t h e d i e t s c o n t a i n i n g P C M I h a d t h e l o w e s t r a t e s o f g a i n , t h e s e b e i n g s i g n i f i c a n t l y d i f f e r e n t f r o m t h o s e f o r pigs g i v e n t h e c o n t r o l

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127 diets and the diets containing the peas. The efficiency of utilization of feed and of dietary ME, CP and DCP was also lowest for the pigs given PCM 1, followed by PCM 2. The pigs given the diets containing peas had similar rates of gain and efficiency of feed, energy and protein utilization as the control animals. Consumption of CP and DCP in relation to gain was lower for the pigs given the low lysine diets, which indicates a higher utilization of DCP for these diets. The evaluation of carcass quality, organ weights and dimensions did not reveal any statistically significant differences between treatments with the high lysine level, while a lower lean percentage and significantly greater depth of side fat were found in pigs given Diet 10 than in the pigs given the control diets containing the low lysine level. Pigs given Diet 10, containing the earliest harvested meal, PCM 1, had carcasses with low meat colour values. No significant differences in relation to the other treatments were found, however. DISCUSSION The higher crude protein content and the lower content of crude fibre of PCM 1 explain the higher digestibility of the nutrients and the higher DE and ME contents of this meal compared with PCM 2. A higher digestibility of crude fibre, NDF and ADF was also found for PCM 1, while the digestibility values of the other carbohydrate fractions were of the same magnitude for both PCM-products. The digestibility values of most nutrients and carbohydrate fractions, and DE and ME contents of PCM 1 are in very close agreement with results obtained with the same cultivar, Simo, harvested at around the corresponding dates by Lund et al. (1981) and I-I~kansson and MalmlSf (1984). The digestibility values of all nutrients in the peas correspond well with the values given in the Swedish feedstuff composition tables (Eriksson et al., 1976). A somewhat higher crude fibre digestibility and ME content were obtained in the present work, 15.5 compared with 14.9 MJ per kg DM given by Eriksson et al. (1976). Earlier Swedish experiments with peas also gave better growth rates and feed utilization compared with control diets based on soya bean meal (Thomke, 1983). The higher nutritive value of PCM 1 compared to PCM 2 was not reflected in the growth trial, however. These results are probably explained by a lower ileal digestibility of DM, CP, starch and fibre polysaccharides in the early harvested meal, which has been found recently in studies by Graham and Aman (1986). These results are also explained by the fact that a larger proportion of the nutrients, especially protein, originated from peas in PCM 2 than in PCM 1. Calculations have shown that peas make up approximately 30 and 50% of the DM of PCM 1 and PCM 2, respectively. The results from the growth experiments also indicate that the avallabil-

128 ity o f t h e a m i n o acids in t h e PCM-diets was s o m e w h a t l o w e r t h a n in the c o n t r o l and pea diets. T h e availability o f the a m i n o acids in the PCMp r o d u c t s does n o t seem t o be higher t h a n the digestibility o f the c r u d e protein. It can be c o n c l u d e d , t h e r e f o r e , t h a t it is possible t o use u p t o 18% o f late-harvested PCM in diets for growing--finishing pigs. It is i m p o r t a n t , h o w e v e r , t h a t the p o d s are filled c o m p l e t e l y at harvest, w h i c h takes place a b o u t 2--3 weeks a f t e r flowering u n d e r n o r m a l conditions. At this stage o f t h e plant's d e v e l o p m e n t a b o u t 50% o f total DM consists o f peas. Harvesting at this stage yields a b o u t 6 0 0 0 - - 7 0 0 0 kg t o t a l DM per ha c o m p a r e d with a yield o f seeds o f o n l y a b o u t 3 0 0 0 kg DM per ha. Studies b y L. R o d h e ( u n p u b l i s h e d results, 1 9 8 6 ) have shown, h o w e v e r , t h a t a b o u t 10% o f the c r o p is lost on harvesting and a b o u t 10% during storage and grinding w h e n using the w h o l e pea crop. ACKNOWLEDGEMENTS

T h e a u t h o r s wish t o t h a n k L a n t b r u k e t s F o n d for financial s u p p o r t and Dr. B. Ogle for valuable criticism and helpful suggestions in the preparation o f the manuscript.

REFERENCES Andersson, K., 1977. Slaktkroppskontroll i svinstamkontrollen. Swedish University of Agricultural Sciences, Konsulentavdelningens rapporter, Allmiint 8, S-750 07 Uppsala, Sweden, pp. 8: 1--8:11. Barr, A.J., Goodnight, H.H., Sail, J.P., Blair, W.P. and Chilko, O.M., 1979. SAS user's guide. Raleigh, NC, SAS InstituteInc. Erikason, S., Sanne, S. and Thomke, S., 1976. Fodermedelstabeller och utfodringsrekommendationer, LT~s fSrlag, Stockholm, pp. 36--39. Graham, H. and )kman, P., 1986. Whole-crop peas. II. Digestion of early and late harvested crops in the gastrointestinal tract of pigs (Unpublished). H~kansson, J. and MalmlSf, K., 1984. The nutritive value of grass-, clover- and peacrop meals for growing pigs. Swed. J. Agric. Res., 14: 45--51. Lund, S., H~kansson, J. and Eriksson, S., 1981. Nutritive value of whole-crop peas for swine. Swedish University of Agricultural Sciences, Department of Animal Nutrition, Report 57, S-750 07 Uppsala, Sweden, 8 pp. MalmlSf, K. and H~kansson, J., 1984. The effect of straw fibre on the diurnal pattern of urinary nitrogen excretion in swine. Swedish J. Agric. Res., 14: 53--57. Petersson, H., I-~kansson, J. and Malmfors, G., 1981. AvkommeprSvning av galtar p~ foder med olika n~ringsinneh~ll. Swedish University of Agricultural Sciences, Konsulentavdelningens rapporter, Allm//nt 33, S-750 07 Uppsala, Sweden, pp. 1:1--1:13. Rundgren, M., 1983. HelgrSdesensilage av ~rter till svin. Swedish University of Agricultural Sciences, Konsulentavdelningens rapporter, Allm~nt 44, S-750 07 Uppsala, Sweden, pp. 7:1--7:9. Thomke, S., 1983. Svinens mSjligheter och begr~nsningar att utnyttja inhemska fodermedel -- i dag och i framtiden. Swedish University of Agricultural Sciences, Konsulentavdelningens rapporter, Allm~/nt 43, S-750 07 Uppsala, Sweden, pp. 6:1---6:10.