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The use of expeller copra meal in grower and finisher pig diets
Livestock Production Science 67 (2000) 55–65 www.elsevier.com / locate / livprodsci
The use of expeller copra meal in grower and finisher pig diets J.V. O’Doherty*, M.P. McKeon Department of Animal Science and Production, Agriculture Building, University College Dublin, Belfield and Lyons Research Farm, Newcastle, Co. Dublin, Ireland Received 16 November 1998; received in revised form 3 September 1999; accepted 14 March 2000
Abstract Two experiments were conducted to determine the nutritive value of copra meal for grower and finisher pigs (40–95 kg). The apparent nutrient digestibility of copra meal, when included at 200 and 400 g kg 21 in the diet of both the grower and finisher pig, was determined in experiment 1. In experiment 2, productive performance was determined in group fed pigs (n 5 360) offered diets ad libitum containing a control diet (0 copra meal) (T1), 100 g copra meal kg 21 (T2) and 200 g copra meal kg 21 (T3) formulated as a direct replacement for barley and 100 g copra meal kg 21 (T4) and 200 g copra meal kg 21 (T5) formulated on a least cost basis. The control and least cost diets were formulated to have similar concentrations of digestible energy and ideal protein. There was a significant interaction in organic matter (OM), protein and energy digestibility between level of copra meal in the diet and age of pig (P , 0.05). The pigs offered the 400 g copra meal kg 21 in the diet had a higher nutrient digestibility during the finisher stage than during the grower stage (P , 0.001). However, age of pig had no effect on nutrient digestibility when the pigs were offered the control diet and the 200 g copra meal kg 21 diets. In experiment 2, there was a linear decrease (P , 0.05) in feed intake as the level of copra meal in the diet increased. There was a significant interaction in growth rate between level of copra meal inclusion and method of formulation (P , 0.01). As the level of copra meal increased in the least cost formulation, growth rate increased (P , 0.05). As the level of copra meal increased in the barley substitution formulation, growth rate decreased (P , 0.05). The inclusion of 200 g copra meal kg 21 in the diet decreased the kill out proportion compared to the control and 100 g copra meal kg 21 (P , 0.01). In conclusion, 200 g copra meal kg 21 can be used in the diet of grower–finisher pigs but its performance will depend on the method of formulation used. 2000 Elsevier Science B.V. All rights reserved. Keywords: Pigs; Diet; Copra meal
1. Introduction The Irish pig industry relies heavily on traditional feedstuffs such as wheat, barley and soya bean meal to formulate pig diets. Because of this dependence, *Corresponding author. Tel.: 1353-1-706-7128; fax: 1353-1706-1103. E-mail address: [email protected] (J.V. O’Doherty).
the industry has few options available to it when these ingredients become expensive. To avoid this problem, alternative cheaper ingredients such as copra meal need to be researched. Copra meal is produced by expeller extracting dried coconut kernels to remove the coconut oil (Butterworth and Fox, 1963). Copra meal is a variable commodity (Thorne et al., 1990) and the variation in the nutrient content of copra meal is fundamentally a function of differ-
0301-6226 / 00 / $ – see front matter 2000 Elsevier Science B.V. All rights reserved. PII: S0301-6226( 00 )00190-1
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ences in residual oil content. As a result of this, the residual ingredient left is moderately high in oil (90–160 g kg 21 ). Copra meal could make a significant contribution to the protein requirements of pigs with a crude protein content of around 200 g kg 21 . However, Thorne et al. (1990) showed the amino acid balance of copra meal protein to be far from ideal with lysine being particularly deficient. Thorne et al. (1990) stated that poor digestibility and an imbalance of essential amino acids in copra meal protein probably result in copra meal contributing little more to the pig’s protein requirement than do dietary cereals. Thorne et al. (1988) found that there was a linear reduction in daily gain as the level of copra meal in the diet increased. However, attention to the dietary amino acid balance may improve performance. Thorne et al. (1992) maintained the ideal amino acid balance with the use of synthetic amino acids at different copra meal inclusion levels and found that there was a linear reduction in daily gain as the level of copra meal in the diet increased from 0 to 200 g kg 21 . However, it should be noted that this experiment was conducted at 258C and this may have affected feed intake especially when the pigs were fed high fibre diets. Copra meal is a potentially valuable source of energy for grower and finisher pig diets. However, with careful diet formulation copra meal may represent a cheap and valuable source of both dietary energy and protein for pigs. The current study was designed to examine the effect of including copra meal in the diet at 100 and 200 g kg 21 , formulated on either a least cost basis or as a direct substitute for barley on the performance of pigs between 40 and 95 kg live weight housed at 188C. A further objective was to estimate the nutrient digestibility of copra meal when included in the diet of grower and finisher pigs at 200 and 400 g kg 21 .
2. Materials and methods
2.1. Digestibility experiment Nine Landrace cross boars of 35 kg live weight were used. The experiment was designed as a 3 (experimental diets) 3 2 (age of pig) factorial. The three digestibility diets were (T1) control diet (0
copra), (T2) control diet (800 g kg 21 ) plus 200 g copra meal kg 21 and (T3) control diet (600 g kg 21 ) plus 400 g copra meal kg 21 . The copra meal used was a commercially produced expeller meal imported from Indonesia and its chemical composition is given in Table 1. Details of the digestibility diets are also shown in Table 1. The nutrient digestibility of the copra meal component was calculated by the difference method using the control treatment (T1) as a basal diet and assuming that the remainder of the diet was unchanged. When formulating the 200 g and 400 g copra meal kg 21 diets, all ingredients present in the control diet were reduced by 20% and 40%, respectively in order to calculate the nutrient digestibility of the copra meal component by the difference method. The pigs were randomly allocated to the three treatments and housed in metabolism cages fitted with urine and faeces separators for the duration of two collection periods. The first collection period occurred during the grower stage (12–14 weeks of age) while the second collection period occurred during the finisher stage (16–18 weeks of age). The cages were located in an environmentally controlled room, maintained at a constant temperature of 248C (61.58C). The trial consisted of an initial 10 days acclimatisation period and a further 10 days during which feed intake and faeces output were recorded. Food was presented to each animal twice daily in the form of a pellet diet with water in the proportion 1:2 w / v and restricted to 0.90 of ad libitum intake in the acclimatisation period. Faeces were collected daily from each pig and were air-dried before being weighed.
2.2. Performance experiment The experiment was designed as a 2 (method of formulation) 3 2 (copra meal level) factorial plus the control diet. The pigs were offered diets containing either a control treatment (0 copra meal) (T1), 100 g copra meal kg 21 (T2) and 200 g copra meal kg 21 (T3) formulated as a direct replacement for barley and 100 g copra meal kg 21 (T4) and 200 g copra meal kg 21 (T5) formulated on a least cost basis. Details of the experimental diets are shown in Table 2. In the least cost formulations, the diets were formulated using standard feeding values for the
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Table 1 Composition of the digestibility diets and analysed chemical composition of the copra meal and the digestibility diets Copra meal
Control
Copra meal (g kg 21 ) 200
400
0 408.7 250 250 35 30 4.75 5.1 14.0 2.5
200 326.9 200 200.8 28 24 3.0 4.1 11.2 2
400 245.1 150 150 21 18 2.9 3.1 8.4 1.5
888.0 60.1 216.9 158.1
886.0 57.6 221.6 239.7
883.0 57.8 223.3 336.7
21
Composition (g kg ) Copra meal Barley Wheat Soya bean meal Tallow Molasses Dicalcium phosphate Salt Lime Mineral and vitamins Chemical composition (g kg 21 ) Dry matter Ash Crude protein Neutral detergent fibre Ether extract Gross energy (MJ kg 21 DM) Lysine (g kg 21 )
882.0 62.0 205.0 493.0 93.0 18.3 4.8
ingredients (Ministry of Agriculture, Fisheries and Food, 1991) so as to contain similar concentrations of digestible energy (DE) (13.8 MJ DE) and ideal protein (lysine 10 g kg 21 ) (Close, 1994) with synthetic amino acids added where necessary. In the least cost formulation, wheat, molasses and soya oil were included equally. Copra meal replaced barley directly at 100 and 200 g kg 21 in the copra meal substituted barley diets. The diets were prepared in 4.5 mm pellet form and delivered in individually identified 25 kg paper bags. The performance experiment was run over two periods. Two hundred and forty entire males (progeny of Landrace 3 Large White sows) were used in the first phase (November–February) of the experiment while a replicate run (March–June) using 120 entire males of identical genotype were used in the second phase. The pigs were penned in groups of twelve and were stocked at 0.84 m 2 per pig. The house was mechanically ventilated to provide an ambient temperature of 188C. Each pen had a solid floor lying area with access to slats at rear. Individual single space feeders with water nipples were present in all pens providing an ad libitum supply of both food and water.
18.7 –
18.8 –
18.8 –
The pigs were allowed 5 days to acclimatise before the experiment began. At the beginning of the experiment each pig was individually weighed, tagged and all pigs were balanced across treatments according to live weight. All pens were weighed after 28 days and again 33 days later. Pigs were removed for slaughter when the average pen weight exceeded 95 kg. Growth measurements ended at first slaughtering but the pigs continued on their dietary treatment up to slaughter. Daily carcass gain was calculated by assuming a 65% kill out percentage for the pigs at the start of the experiment as follows: (Carcass weight 2 (initial weight 3 0.65)) /(number of days) Within 1 h of slaughter, the warm carcass was weighed and subcutaneous back fat and eye muscle depth measurements were taken 6.5 cm from the midline of the split back between the 3rd and 4th last ribs using a Hennessy grading probe. Lean meat proportion was estimated from the back fat and eye muscle depth measurements using the equation (Department of Agriculture and Food, 1994):
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Table 2 Composition and analysed chemical composition of the performance diets Copra inclusion (g kg 21 ) Formulation Composition (g kg 21 ) Barley Wheat Soya bean hipro Copra meal Tallow Molasses Soya oil Salt Dicalcium phosphate Limestone Minerals and vitamins Synthetic amino acids Lysine Methionine Chemical composition (g kg 21 ) DM Ash Fat Crude fibre Crude protein Lysine Methionine and cystine Threonine Calcium Phosphorus Digestible energy content (MJ kg 21 )a
T1 Control
T2 100 Barley
T3 200 Barley
T4 100 Least cost
T5 200 Least cost
354.3 300.0 251.0 0 30.0 30.0 10.0 3.5 6.0 9.8 2.5
254.3 300.0 251.0 100.0 30.0 30.0 10.0 3.5 6.0 9.8 2.5
154.3 300.0 251.0 200.0 30.0 30.0 10.0 3.5 6.0 9.8 2.5
265.0 300.0 246.9 100.0 24.2 30.0 10.0 3.5 5.1 10.0 2.5
176.9 300.0 242.0 200.0 17.3 30.0 10.0 3.5 4.2 10.9 2.5
2.0 0.9
2.0 0.9
2.0 0.9
2.0 0.8
2.0 0.7
884.5 54 60 43 195 10.8 6.2 7.5 6.6 5.5
876.0 58 69 49 209 11.1 6.4 7.8 6.6 5.4
870.5 62 77 55 231 11.2 6.6 8.2 6.9 5.6
878.5 50 60 49 206 11.0 6.2 7.6 6.6 5.5
872.2 54 61 56 213 11.0 6.3 7.6 6.6 5.5
13.85
14.05
14.25
13.93
13.97
a
The DE content of the diets was calculated using the estimated DE content of the copra meal obtained from the digestibility experiment while the DE value for the remainder of the ingredients were obtained from official feeding tables (Ministry of Agriculture, Fisheries and Food, 1991).
Estimated lean meat proportion (g kg 21 ) 5 655.4 2 13.498 3 probe fat (mm) 1 0.177 3 (probe fat, mm)2 1 0.719 3 muscle depth (mm)
2.3. Chemical analysis The chemical analysis of dry matter, crude protein and ash were carried out according to the AOAC (1980). The dry matter contents of the feeds and faeces were determined by oven drying at 558C for 72 h with forced air circulation. The dried concentrates and faeces were milled through a 1-mm screen (Christy and Norris hammer mill) and analysed for
ash by burning in a furnace at 6008C for 4 h, crude protein by the macro-Kjeldahl method (Kjeldahl N3 6.25), neutral detergent fibre (NDF) content by the method of Van Soest (1976), crude fibre by the Weende method (AOAC, 1980). Ether extract was determined using the 1043 Soxtec System HT6 as derived from the Soxlet method. The amino acid compositions of the diet were determined by the method of Iwaki et al. (1987).
2.4. Statistical analysis The data was analysed using least square procedures (Proc. GLM of the Statistical Analysis
J.V. O’ Doherty, M.P. McKeon / Livestock Production Science 67 (2000) 55 – 65
System [SAS, 1985] version 5.16). In the digestibility experiment, the data was analysed as a 3 (diets)3 2 (age) factorial design. The model was partitioned into the main effects of diet, age of pig, pig effect and the interaction of diet and age of pig. The individual pig served as the experimental unit. In the performance experiment, the overall effect of level of copra meal and method of formulation on pig performance and carcass characteristics were analysed as a 232 factorial. In addition orthogonal contrasts were made between the control and the four copra meal diets (T2, T3, T4 and T5), between the control and the 100 g copra meal kg 21 diets (T2 and T4) and between the control and the 200 g copra meal kg 21 diets (T3 and T5). The kill-out, back fat and lean meat were adjusted for slaughter weight by covariance analysis. The individual pen served as the experimental unit.
59
Table 3. There was a significant interaction in organic matter (OM), protein and energy digestibility between level of copra meal in the diet and age of pig (P,0.05). The pigs offered the 400 g copra meal kg 21 in the diet had a significantly higher OM, protein and energy digestibility (P,0.05) in the finisher stage than in the grower stage. However, age of pig had no effect on nutrient digestibility when the pigs were fed the control and 200 g copra meal kg 21 diets. Pigs offered the control diet had a significantly lower fibre digestibility than pigs offered the 200 and 400 g copra meal kg 21 diets (P,0.05). The nutrient digestibility coefficients and the DE content of the copra meal component of the diet are presented in Table 4. There was a tendency for the digestibility of the OM, protein and energy and the DE content of the copra meal to decrease as the level of copra meal in the test diet increased.
3.2. Performance experiment 3. Results Mean initial live weight was 39.9 kg (S.D.50.31) with no difference between treatments. During the experiment, two pigs were removed from their treatments (death and tail biting). The effect of dietary treatment on feed intake and DE intake is
3.1. Digestibility experiment The effects of diet and age of pig on apparent nutrient digestibility coefficients are presented in
Table 3 Effects of diet and age of pig on apparent nutrient digestibility coefficients of the diets (L.S.M.6S.E) Diet
S.E.
Control
Digestibility coefficients Organic matter Protein Neutral detergent fibre Energy a
200 g copra meal kg
21
400 g copra meal kg
21
Grower
Finisher
Grower
Finisher
Grower
Finisher
0.882 0.892 0.592 0.878
0.878 0.892 0.563 0.874
0.871 0.848 0.717 0.868
0.878 0.865 0.708 0.876
0.846 0.776 0.754 0.843
0.875 0.847 0.800 0.870
Significance Diet
0.008 0.012 0.022 0.006
* *** *** *
Age
Diet3Age
**
* * *
* P,0.05; ** P,0.01; *** P,0.001.
Table 4 Mean digestibility coefficients for organic matter, protein, energy and digestibile energy (DE) content (MJ kg 21 DM) of copra meal Copra meal (g kg 21 )
Organic matter
Protein
Energy
DE content
200 400
87.9 84.8
84.6 74.8
85.5 82.8
16.4 15.7
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Table 5 Effect of dietary treatment on feed intake and digestible energy intake (L.S.M.6S.E.) Treatments
S.E.
Significance Contrast a
1 Control
2 100 Barley
3 200 Barley
4 100 Least cost
5 200 Least cost
Grower phase (0–28 days) Intake (kg day 21 ) Digestible energy (MJ day 21 )
1.95 26.9
1.91 26.8
1.79 26.5
1.92 26.7
1.88 26.3
0.066 0.93
Finisher phase (28–61 days) Intake (kg day 21 ) Digestible energy (MJ day 21 )
2.88 39.9
2.73 38.4
2.52 35.8
2.69 37.5
2.63 36.7
0.077 1.09
** *
2.32 32.6
2.15 30.7
2.31 32.4
2.26 31.5
0.059 0.84
** *
Copra inclusion (g kg Formulation
21
)
Combined grower–finisher phase (0–61 days) Intake (kg day 21 ) 2.42 Digestible energy (MJ day 21 ) 33.5
Contrast b
Contrast c
Contrast d
*
*
*** **
*
** *
*
a
Contrast between the control and the four diets (control vs. T2, T3, T4 and T5). Contrast between the control and the 100 g copra meal kg 21 diets (control vs. T2 and T4). c Contrast between the control and the 200 g copra meal kg 21 diets (control vs. T3 and T5). d Contrast between the 100 g kg 21 and the 200 g copra meal kg 21 diets (T2 and T4 vs. T3 and T5). * P,0.05; ** P,0.01; *** P,0.001. b
presented in Table 5 while the effect of treatment on growth rate, feed and DE conversion ratios and live weight is presented in Table 6. The DE content of the diets was calculated using the estimated DE content of the copra meal obtained from the digestibility experiment while the DE values for the remainder of the ingredients were obtained from official feeding tables (Ministry of Agriculture, Fisheries and Food, 1991). Experimental period had no effect on any variable measured. The inclusion of copra meal in the diet decreased feed intake during both the finisher period (P,0.01) and the grower–finisher period (P,0.01) compared to the control diet. Pigs offered the control diet had a significantly higher feed intake than the pigs offered the 100 g (P,0.05) and 200 g copra meal kg 21 (P,0.001) in the diet during the finisher period. Pigs offered the 100 g copra meal kg 21 had a higher intake than the pigs offered the 200 g copra meal kg 21 in the diet (P,0.05) during both the finisher period and grower–finisher period. The inclusion of copra meal in the diet decreased DE intake during the finisher period (P,0.05) and during the grower–finisher period (P,0.05) compared to the control diet. Pigs offered the control diet
had a higher DE intake than the pigs offered the 200 g copra meal kg 21 in the diet during both the finisher period (P,0.01) and combined grower and finisher period (P,0.05). There was a significant interaction (P,0.01) in growth rate between level of copra meal inclusion and method of formulation during the finisher and combined grower and finisher period. As the level of copra meal in the diet increased in the least cost formulation, growth rate increased (P,0.05). However, as the level of copra meal in the diet increased in the barley substitution formulation, growth rate decreased (P,0.05). Pigs offered the control had a higher live weight gain (P,0.05) than the pigs offered the 200 g copra meal kg 21 during the grower period. The pig live weights at the end of the grower period were lighter for the pigs fed the 200 g kg 21 copra meal in the diet (P,0.05) and this reflected the trends in growth rate. The inclusion of copra meal in the diet improved food conversion ratio (FCR) during the finisher and combined grower–finisher periods (P,0.05) compared to the control diet. Pigs offered the 200 g copra meal kg 21 had a significantly better FCR than the control and the 100 g kg 21 copra meal fed pigs
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Table 6 Effect of dietary treatment on pig performance (L.S.M.6S.E.) Treatments
S.E. 2 10 Barley
3 20 Barley
4 10 Least cost
5 20 Least cost
Initial weight (kg)
40.0
40.1
39.5
39.6
40.2
0.85
Grower phase (0–28 days) Live weight gain (kg day 21 ) Food conversion ratio (g g 21 ) DE conversion ratio (MJ kg 21 )f Live weight at 28 days
0.824 2.47 33.1 63.4
0.833 2.39 32.4 63.7
0.781 2.43 33.5 61.3
0.799 2.50 33.8 62.0
0.809 2.49 33.6 63.1
0.025 0.081 1.12 1.43
Finisher phase (28–61 days) Live weight gain (kg day 21 ) Food conversion ratio (g g 21 ) DE conversion ratio (MJ kg 21 )f Live weight at 61 days
0.940 2.77 42.4 94.2
0.929 2.75 42.3 94.0
0.899 2.55 40.1 90.7
0.916 2.67 41.0 92.0
0.980 2.47 38.4 95.1
0.026 0.071 1.08 1.61
Combined grower–finisher phase (0–61 days) Live weight gain (kg day 21 ) 0.886 0.884 Food conversion ratio (g g 21 ) 2.63 2.57 DE conversion ratio (MJ kg 21 )f 37.9 37.4
0.843 2.50 36.9
0.862 2.59 37.5
0.897 2.48 36.1
0.020 0.054 0.79
21
Copra inclusion (g kg ) Formulation
Contrast 1a
1 Control
2b
3c
4d
5e
*
* ** *
** *
*
*
* *
**
a
Contrast between the control and the four diets (control vs. T2, T3, T4 and T5). Contrast between the control and the 100 g copra meal kg 21 diets (control vs. T2 and T4). c Contrast between the control and the 200 g copra meal kg 21 diets (control vs. T3 and T5). d Contrast between the 100 g and the 200 g copra meal kg 21 diets (T2 and T4 vs. T3 and T5). e Interaction between method of formulation and copra meal level. f DE conversion ratio: digestible energy conversion ratio (MJ kg 21 live weight). * P,0.05; ** P,0.01; *** P,0.001. b
(P,0.05) during the finisher period. Pigs fed the 200 g copra meal kg 21 also had a significantly better DE conversion ratio than the control and 100 g copra meal kg 21 during the finisher period (P,0.05). The effect of diet on carcass characteristics is presented in Table 7. The inclusion of copra meal in the diet decreased carcass weight (P,0.01) and kill out proportion (P,0.01). Pigs offered the control diet and the 100 g copra meal kg 21 had significantly higher carcass weight (P,0.01) and kill out proportion (P,0.001) than the pigs offered the 200 g copra meal kg 21 diet. Pigs offered copra meal formulated on a least cost basis had a significantly heavier carcass weight (72.2 vs. 71.5 kg, S.E.M. 0.76: P, 0.05) and a lower killing out proportion (72.2 vs. 72.9, S.E.M 0.30: P,0.05) than the pigs fed copra meal as a direct replacement for barley. Dietary treatment had no effect on lean meat or back fat
depth. Pigs offered the control diet had a significantly better carcass average daily gain (P,0.05) than the pigs offered the copra meal diets. Carcass FCR and carcass DE conversion ratio were unaffected by dietary treatment.
4. Discussion The OM, protein and energy digestibility coefficients decreased as the level of copra meal in the diet increased. The nutrient digestibility of the diets decreased with increased neutral detergent fibre in the diet. Similar results were reported by Noblet and Perez (1993) who observed that a high level of fibre in the diet resulted in some of the OM, protein and energy in the diet becoming unavailable. This may be due to fibre hindering the access of digestive
J.V. O’ Doherty, M.P. McKeon / Livestock Production Science 67 (2000) 55 – 65
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Table 7 Effect of dietary treatment on carcass performance (L.S.M.6S.E.) Treatments
Copra inclusion (g kg Formulation
21
)
Carcass characteristics Slaughter weight (kg) Cold carcass weight (kg) Kill out (g kg 21 ) Backfat P2 (mm) Lean meat (g kg 21 ) Carcase gain (g day 21 ) Carcase FCR (g g 21 ) Carcase DE conversion ratio (MJ kg 21 )e
S.E.
1 Control
2 100 Barley
3 200 Barley
4 100 Least cost
5 200 Least cost
97.9 72.1 734.0 13.3 540.0 0.695 3.50 51.6
99.4 73.8 731.0 13.0 544.4 0.704 3.33 51.3
95.4 69.2 727.0 11.9 556.0 0.656 3.29 51.2
96.0 72.5 731.0 12.2 552.0 0.709 3.28 51.4
99.4 72.0 713.0 12.9 548.0 0.702 3.26 50.1
Contrast 1a
1.29 1.14 0.40 0.89 5.20 0.014 0.097 1.08
2b
3c
4d
** **
*** ***
** **
*
*
a
Contrast between the control and the four diets (control vs. T2, T3, T4 and T5). Contrast between the control and the 100 g copra meal kg 21 diets (control vs. T2 and T4). c Contrast between the control and the 200 g copra meal kg 21 diets (control vs. T3 and T5). d Contrast between the 100 g and the 200 g copra meal kg 21 diets (T2 and T4 vs. T3 and T5). e Carcass DE conversion ratio: Digestible energy per kg carcass (MJ kg 21 carcass weight). * P,0.05; ** P,0.01; *** P,0.001. b
enzymes to the cell contents (Bach-Knudsen et al., 1993). Fibre has been observed to increase the digesta rate of passage (Low, 1993) and this may reduce the time available to the digestive enzymes to act on the other substrates. The current experiment shows that the nutrient digestibility of the diets can vary with age and bodyweight of the animals. However, this variation in digestibility is ingredient related. The 400 g copra meal kg 21 diet was digested better by the finisher pig than the grower pig, probably due to a better developed hind gut fermentation. The depressive effect of fibre is more pronounced in growing pigs than finishing pigs, particularly at high NDF content. Similar results were reported by Noblet et al. (1994) who stated that fibrous feeds were better digested by older animals such as sows due to their better developed hind gut fermentation and lower feeding level relative to maintenance. Due to these factors, Noblet and Bourdon (1997) showed that the DE content of diets for sows was 4 MJ higher for high fibre by-products and 0.2–0.5 MJ for cereals than when compared to younger pigs. The DE content of copra meal when estimated using 200 g kg 21 copra meal in the test diet was very similar to the 15.5 MJ DE kg 21 DM determined by
Thorne (1986) and Dore (1999) which had a residual oil content of 91 g kg 21 similar to the oil content of the copra meal (93 g kg 21 ) used in the current experiment.
4.1. Performance experiment During the grower–finisher period, pigs offered increasing levels of copra meal in the diet had lower intakes than the control fed pigs. This reduction in intake may be due to the increasing level of energy and fibre in the diet, both of which increase as the level of copra meal in the diet increases. Reductions in voluntary feed intake are often responses to changes in dietary nutrient balance such as increased energy level (Cole et al., 1972; Cole and Chadd, 1989) or imbalances in the dietary amino acid supply (Harper et al., 1970). Thorne et al. (1992) observed that increasing dietary copra meal decreased feed intake also. These authors attributed this to increased fibre in the diet hence reducing intake through its effect on gut fill. The reduced feed intake with copra meal inclusion could also be due to a high arginine content (Thorne, 1986). There may also be a palatability problem with high inclusion levels of copra meal.
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The pigs offered the control diet had a higher live weight gain than the pigs offered the 200 g copra meal kg 21 during the grower period. However, there was no difference in growth rate during the finisher period and live weight at the end of the experiment was similar for the control, 100 and 200 g copra meal kg 21 diets. This was surprising since Thorne et al. (1988) found that there was a linear reduction in daily gain as the level of copra meal in the diet increased. However, in the current experiment, careful attention was given to the amino acid balance and all least cost diets were formulated to an ideal protein (Close, 1994). However, the daily live weight gain of the pigs offered copra meal may have been over estimated. On a carcass basis the pigs fed the control diet had a better carcass daily gain than the pigs fed the 200 g copra meal kg 21 . These pigs also had a higher carcass weight and kill out proportion than the pigs offered the copra meal diets. The lower kill out proportion of the 200 g copra meal kg 21 fed pigs was due to the negative effect of the dietary fibre. The low kill out proportion subsequently reduced cold carcass weight in the 200 g copra meal kg 21 fed pigs. Fibre extends the gut thereby reducing the kill out proportion. This agrees with Jorgensen et al. (1996) who stated that a high fibre diet would increase the length and weight of the intestinal tract. There was also a depression in growth rate in the pigs offered the 200 g copra meal kg 21 as a direct replacement for barley. This decrease in growth rate may be due to a number of reasons These are decreased feed intake and excess fat and protein. This depression in growth rate may be due to the lower feed intake with the 200 g copra meal kg 21 substituted barley diet. A number of studies have found that the pig will regulate voluntary intake according to the energy density of the diet (Cole et al., 1972; Cole and Chadd, 1989). In the 200 g copra meal kg 21 substituted barley diet, feed intake decreased as the energy concentration of the diet increased. However, in terms of total daily energy intake, compensation was not complete. The numerical tendency for a decline in backfat thickness observed with this diet is consistent with a reduction in DE intake. The depression in intake would also result in these pigs having lower lysine intakes during the grower
63
and finisher periods. The digestibility experiment showed that as the level of copra meal in the diet increased, protein digestibility decreased. The decrease in protein digestibility would have a greater effect at lower feed intake, thereby decreasing protein availability and ultimately amino acid intake and availability. If protein is below requirements, nitrogen deposition rate will be reduced (Rao and McCracken, 1991). The increased fat content of this diet may also hinder fibre digestibility. Kavanagh (1998) reported lower digestibility of fibre in diets supplemented with high levels of fat. There is evidence from ruminants that supplementary fat in the diet results in an inhibition of rumen microflora (Brooks et al., 1954). It is possible that this may also apply to the large intestine of the pig. Bakker (1996) found that adding animal fat to fibrous diets had a negative effect on fermentation in the dietary tract of the pig. Fibre is one of the primary substrates fermented in the large intestine (Varel, 1987) and Dierick et al. (1989) suggest that volatile fatty acids make a small but important contribution to the energy supply of the pig. The control fed pigs had the worst FCR while 200 g copra meal kg 21 in the diet had the best FCR. The poorer FCR of the control fed pigs, especially during the finisher period is probably due to these pigs having too high an ad libitum feed intake. Campbell et al. (1985) found that the FCR improved with each increase in energy intake up to 33 MJ DE per day in similar live weight pigs. In the present experiment, there was a marked change in the effects of feeding rate on FCR when DE intake exceeded 35 MJ day 21 . The numerical tendency for an increase in backfat thickness observed with this diet is consistent with the DE intake. The FCR may also be underestimated in the pigs fed the 200 g copra meal kg 21 in the diet, as a result of the increased gut fill which will influence live weight gain. However, when efficiency was measured in terms of the amount of the DE required per kg carcass, there was no difference in efficiency between the control, 100 and 200 g copra meal kg 21 diets. It can be concluded from the in vivo digestibility studies that increasing levels of copra meal in the diet will lower nutrient digestibility. However, copra
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meal is an excellent source of energy for pigs and the DE values obtained in this study are similar to other previously quoted values. Careful consideration must be given to inclusion of copra meal in pig diets. Formulating diets on the basis of least cost favours the inclusion of copra meal. The inclusion of copra meal at 200 g kg 21 as a replacement for barley lowers pig performance and should be avoided. The inclusion of 200 g kg 21 copra meal on the basis of least cost does not affect performance but careful consideration must be given to intake and killing out proportion. High levels of copra meal should be favourable for heavy pigs and sows.
Acknowledgements We are grateful to James Callan and Bernie Flynn for assistance with laboratory analysis and to HKM Milling Ltd. for financial assistance.
References AOAC, 1980. Official Methods of Analysis, 13th Edition. Association of Official Analytical Chemists, Washington, DC. Bach-Knudsen, K.E., Jensen, B.B., Hansen, I., 1993. Digestion of polysaccharides and other major components in the small and large intestine of pigs fed on diets consisting of oat fractions rich in beta-D-glucan. Br. J. Nutr. 119, 879–886. Bakker, G.C.M., 1996. Interaction between carbohydrates and fat in pigs. PhD thesis, Institute of Animal Science and Health (ID-DLO), Department of Nutrition for Pigs and Poultry, P.O. Box 65, 800 AB Lelystad, The Netherlands. Brooks, C.C., Garner, G.B., Gehrke, C.W., Muhrer, M.E., Pfander, W.H., 1954. The effect of added fat on the digestion of cellulose and protein by ovine rumen organisms. J. Anim. Sci. 13, 758–764. Butterworth, M.H., Fox, H.C., 1963. The effects of heat treatment on the nutritive value of coconut meal, and the prediction of nutritive value by chemical methods. Br. J. Nutr. 17, 445–451. Campbell, R.G., Taverner, M.R., Curic, D.M., 1985. Effects of sex and energy intake between 48 and 90 kg live weight on protein deposition in growing pigs. Anim. Prod. 40, 497–503. Close, W.H., 1994. Feeding new genotypes: establishing amino acid / energy requirements. In: Cole, D.J.A., Wiseman, J., Varley, M.A. (Eds.), Principles of Pig Science. Nottingham University Press, Nottingham, pp. 123–140. Cole, D.J.A., Chadd, S.A., 1989. Voluntary food intake of growing pigs. Br. Soc. Anim. Prod. Occ. Publ. 13, 61–70. Cole, D.J.A., Hardy, B., Lewis, D., 1972. Nutrient density of pig
diets. In: Cole, D.J.A. (Ed.), Pig Production. Butterworths, London, pp. 243–257. Dierick, N.A., Vervaeke, I.J., Demeyer, D.I., Decuypere, J.A., 1989. Approach to the energetic importance of fibre digestion in pigs. I. Importance of fermentation in the overall energy supply. Anim. Feed Sci. Techol. 23, 141–167. Department of Agriculture and Food, 1994. Pig carcass dressing specification. DAF, Dublin, SI 216. Dore, M.G., 1999. Studies related to in vivo and in vitro digestibilities of pig feed ingredients. M.Agric.Sci. thesis, National University of Ireland. Harper, A.E., Benevenga, N.J., Wohlheuter, R.M., 1970. Effects of ingestion of disproportionate amounts of amino acid levels. Physiol. Rev. 50, 428–558. Iwaki, K., Nimura, N., Hiraga, Y., Kinoshita, T., Takeda, K., Ogura, H., 1987. Amino acid analysis by reversed-phase highperformance liquid chromatography. J. Chromatogr. 407, 273– 279. Jorgensen, H., Zhao, X.Q., Eggum, B.O., 1996. The influence of dietary fibre and environmental temperature on the development of the gastrointestinal tract, digestibility, degree of fermentation in the hind-gut and energy metabolism in pigs. Br. J. Nutr. 75, 365–378. Kavanagh, S., 1998. Studies on the nutritive value of feedstuffs for pigs. PhD thesis, National University of Ireland. Low, A.G., 1993. Role of dietary fibre in pig diets. In: Cole, D.J.A., Haresign, W., Garnsworthy, P.C. (Eds.). Recent Developments in Pig Nutrition, Vol. 2. Nottingham Press, London, pp. 137–161. Ministry of Agriculture, Fisheries and Food, Fisheries and Food, 1991. The feeding-stuffs regulations 1991. Statutory instrument no. 2840, 9.76. Her Majesty’s Stationary Office, London. Noblet, J., Perez, J.M., 1993. Prediction of digestibility of nutrients and energy values of pig diets from chemical. J. Anim. Sci. 71, 3389–3398. Noblet, J., Bourdon, D., 1997. Valeur energetique comparee de onze matieres premieres chez le porc en croissance et la truie adulte. J. Rech. Porc France 29, 221–226. Noblet, J., Shi, X.S., Dubois, S., 1994. Effect of body weight on net energy values of feeds for growing pigs. J. Anim. Sci. 72, 648–657. Rao, D.S., McCracken, K.J., 1991. Effects of energy intake on protein and energy metabolism of boars of high genetic potential for lean growth. Anim. Prod. 52, 499–507. SAS, 1985. Statistical analysis systems. SAS Institute Inc., Cary, NC. Thorne, P.J., 1986. The use of copra meal in pig diets. PhD thesis, University of Nottingham. Thorne, P.J., Wiseman, J., Cole, D.J.A., Machin, D.H., 1988. Use of diets containing copra meal for growing / finishing pigs and their supplementation to improve animal performance. Trop. Agric. Trinidad 65, 197–201. Thorne, P.J., Wiseman, J., Cole, D.J.A., 1990. Copra meal. In: Thacker, P.A., Kirkwood, R.N. (Eds.), Non-Traditional Feed Sources For Use in Swine Production. Butterworth, London, pp. 127–134.
J.V. O’ Doherty, M.P. McKeon / Livestock Production Science 67 (2000) 55 – 65 Thorne, P.J., Wiseman, J., Cole, D.J.A., Machin, D.H., 1992. Effects of level of inclusion of copra meal in balanced diets supplemented with synthetic amino acids on growth and fat deposition and composition in growing pigs fed ad libitum at a constant temperature. Anim. Feed Sci. Technol. 40, 31–40.
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Van Soest, P.J., 1976. In: Swan, H., Lewis, D. (Eds.), Feed and Energy Sources for Livestock. Butterworth, London. Varel, V.H., 1987. Activity of fibre degrading microorganisms in the pig large intestine. J. Anim. Sci. 65, 488–496.
The use of expeller copra meal in grower and finisher pig diets J.V. O’Doherty*, M.P. McKeon Department of Animal Science and Production, Agriculture Building, University College Dublin, Belfield and Lyons Research Farm, Newcastle, Co. Dublin, Ireland Received 16 November 1998; received in revised form 3 September 1999; accepted 14 March 2000
Abstract Two experiments were conducted to determine the nutritive value of copra meal for grower and finisher pigs (40–95 kg). The apparent nutrient digestibility of copra meal, when included at 200 and 400 g kg 21 in the diet of both the grower and finisher pig, was determined in experiment 1. In experiment 2, productive performance was determined in group fed pigs (n 5 360) offered diets ad libitum containing a control diet (0 copra meal) (T1), 100 g copra meal kg 21 (T2) and 200 g copra meal kg 21 (T3) formulated as a direct replacement for barley and 100 g copra meal kg 21 (T4) and 200 g copra meal kg 21 (T5) formulated on a least cost basis. The control and least cost diets were formulated to have similar concentrations of digestible energy and ideal protein. There was a significant interaction in organic matter (OM), protein and energy digestibility between level of copra meal in the diet and age of pig (P , 0.05). The pigs offered the 400 g copra meal kg 21 in the diet had a higher nutrient digestibility during the finisher stage than during the grower stage (P , 0.001). However, age of pig had no effect on nutrient digestibility when the pigs were offered the control diet and the 200 g copra meal kg 21 diets. In experiment 2, there was a linear decrease (P , 0.05) in feed intake as the level of copra meal in the diet increased. There was a significant interaction in growth rate between level of copra meal inclusion and method of formulation (P , 0.01). As the level of copra meal increased in the least cost formulation, growth rate increased (P , 0.05). As the level of copra meal increased in the barley substitution formulation, growth rate decreased (P , 0.05). The inclusion of 200 g copra meal kg 21 in the diet decreased the kill out proportion compared to the control and 100 g copra meal kg 21 (P , 0.01). In conclusion, 200 g copra meal kg 21 can be used in the diet of grower–finisher pigs but its performance will depend on the method of formulation used. 2000 Elsevier Science B.V. All rights reserved. Keywords: Pigs; Diet; Copra meal
1. Introduction The Irish pig industry relies heavily on traditional feedstuffs such as wheat, barley and soya bean meal to formulate pig diets. Because of this dependence, *Corresponding author. Tel.: 1353-1-706-7128; fax: 1353-1706-1103. E-mail address: [email protected] (J.V. O’Doherty).
the industry has few options available to it when these ingredients become expensive. To avoid this problem, alternative cheaper ingredients such as copra meal need to be researched. Copra meal is produced by expeller extracting dried coconut kernels to remove the coconut oil (Butterworth and Fox, 1963). Copra meal is a variable commodity (Thorne et al., 1990) and the variation in the nutrient content of copra meal is fundamentally a function of differ-
0301-6226 / 00 / $ – see front matter 2000 Elsevier Science B.V. All rights reserved. PII: S0301-6226( 00 )00190-1
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J.V. O’ Doherty, M.P. McKeon / Livestock Production Science 67 (2000) 55 – 65
ences in residual oil content. As a result of this, the residual ingredient left is moderately high in oil (90–160 g kg 21 ). Copra meal could make a significant contribution to the protein requirements of pigs with a crude protein content of around 200 g kg 21 . However, Thorne et al. (1990) showed the amino acid balance of copra meal protein to be far from ideal with lysine being particularly deficient. Thorne et al. (1990) stated that poor digestibility and an imbalance of essential amino acids in copra meal protein probably result in copra meal contributing little more to the pig’s protein requirement than do dietary cereals. Thorne et al. (1988) found that there was a linear reduction in daily gain as the level of copra meal in the diet increased. However, attention to the dietary amino acid balance may improve performance. Thorne et al. (1992) maintained the ideal amino acid balance with the use of synthetic amino acids at different copra meal inclusion levels and found that there was a linear reduction in daily gain as the level of copra meal in the diet increased from 0 to 200 g kg 21 . However, it should be noted that this experiment was conducted at 258C and this may have affected feed intake especially when the pigs were fed high fibre diets. Copra meal is a potentially valuable source of energy for grower and finisher pig diets. However, with careful diet formulation copra meal may represent a cheap and valuable source of both dietary energy and protein for pigs. The current study was designed to examine the effect of including copra meal in the diet at 100 and 200 g kg 21 , formulated on either a least cost basis or as a direct substitute for barley on the performance of pigs between 40 and 95 kg live weight housed at 188C. A further objective was to estimate the nutrient digestibility of copra meal when included in the diet of grower and finisher pigs at 200 and 400 g kg 21 .
2. Materials and methods
2.1. Digestibility experiment Nine Landrace cross boars of 35 kg live weight were used. The experiment was designed as a 3 (experimental diets) 3 2 (age of pig) factorial. The three digestibility diets were (T1) control diet (0
copra), (T2) control diet (800 g kg 21 ) plus 200 g copra meal kg 21 and (T3) control diet (600 g kg 21 ) plus 400 g copra meal kg 21 . The copra meal used was a commercially produced expeller meal imported from Indonesia and its chemical composition is given in Table 1. Details of the digestibility diets are also shown in Table 1. The nutrient digestibility of the copra meal component was calculated by the difference method using the control treatment (T1) as a basal diet and assuming that the remainder of the diet was unchanged. When formulating the 200 g and 400 g copra meal kg 21 diets, all ingredients present in the control diet were reduced by 20% and 40%, respectively in order to calculate the nutrient digestibility of the copra meal component by the difference method. The pigs were randomly allocated to the three treatments and housed in metabolism cages fitted with urine and faeces separators for the duration of two collection periods. The first collection period occurred during the grower stage (12–14 weeks of age) while the second collection period occurred during the finisher stage (16–18 weeks of age). The cages were located in an environmentally controlled room, maintained at a constant temperature of 248C (61.58C). The trial consisted of an initial 10 days acclimatisation period and a further 10 days during which feed intake and faeces output were recorded. Food was presented to each animal twice daily in the form of a pellet diet with water in the proportion 1:2 w / v and restricted to 0.90 of ad libitum intake in the acclimatisation period. Faeces were collected daily from each pig and were air-dried before being weighed.
2.2. Performance experiment The experiment was designed as a 2 (method of formulation) 3 2 (copra meal level) factorial plus the control diet. The pigs were offered diets containing either a control treatment (0 copra meal) (T1), 100 g copra meal kg 21 (T2) and 200 g copra meal kg 21 (T3) formulated as a direct replacement for barley and 100 g copra meal kg 21 (T4) and 200 g copra meal kg 21 (T5) formulated on a least cost basis. Details of the experimental diets are shown in Table 2. In the least cost formulations, the diets were formulated using standard feeding values for the
J.V. O’ Doherty, M.P. McKeon / Livestock Production Science 67 (2000) 55 – 65
57
Table 1 Composition of the digestibility diets and analysed chemical composition of the copra meal and the digestibility diets Copra meal
Control
Copra meal (g kg 21 ) 200
400
0 408.7 250 250 35 30 4.75 5.1 14.0 2.5
200 326.9 200 200.8 28 24 3.0 4.1 11.2 2
400 245.1 150 150 21 18 2.9 3.1 8.4 1.5
888.0 60.1 216.9 158.1
886.0 57.6 221.6 239.7
883.0 57.8 223.3 336.7
21
Composition (g kg ) Copra meal Barley Wheat Soya bean meal Tallow Molasses Dicalcium phosphate Salt Lime Mineral and vitamins Chemical composition (g kg 21 ) Dry matter Ash Crude protein Neutral detergent fibre Ether extract Gross energy (MJ kg 21 DM) Lysine (g kg 21 )
882.0 62.0 205.0 493.0 93.0 18.3 4.8
ingredients (Ministry of Agriculture, Fisheries and Food, 1991) so as to contain similar concentrations of digestible energy (DE) (13.8 MJ DE) and ideal protein (lysine 10 g kg 21 ) (Close, 1994) with synthetic amino acids added where necessary. In the least cost formulation, wheat, molasses and soya oil were included equally. Copra meal replaced barley directly at 100 and 200 g kg 21 in the copra meal substituted barley diets. The diets were prepared in 4.5 mm pellet form and delivered in individually identified 25 kg paper bags. The performance experiment was run over two periods. Two hundred and forty entire males (progeny of Landrace 3 Large White sows) were used in the first phase (November–February) of the experiment while a replicate run (March–June) using 120 entire males of identical genotype were used in the second phase. The pigs were penned in groups of twelve and were stocked at 0.84 m 2 per pig. The house was mechanically ventilated to provide an ambient temperature of 188C. Each pen had a solid floor lying area with access to slats at rear. Individual single space feeders with water nipples were present in all pens providing an ad libitum supply of both food and water.
18.7 –
18.8 –
18.8 –
The pigs were allowed 5 days to acclimatise before the experiment began. At the beginning of the experiment each pig was individually weighed, tagged and all pigs were balanced across treatments according to live weight. All pens were weighed after 28 days and again 33 days later. Pigs were removed for slaughter when the average pen weight exceeded 95 kg. Growth measurements ended at first slaughtering but the pigs continued on their dietary treatment up to slaughter. Daily carcass gain was calculated by assuming a 65% kill out percentage for the pigs at the start of the experiment as follows: (Carcass weight 2 (initial weight 3 0.65)) /(number of days) Within 1 h of slaughter, the warm carcass was weighed and subcutaneous back fat and eye muscle depth measurements were taken 6.5 cm from the midline of the split back between the 3rd and 4th last ribs using a Hennessy grading probe. Lean meat proportion was estimated from the back fat and eye muscle depth measurements using the equation (Department of Agriculture and Food, 1994):
J.V. O’ Doherty, M.P. McKeon / Livestock Production Science 67 (2000) 55 – 65
58
Table 2 Composition and analysed chemical composition of the performance diets Copra inclusion (g kg 21 ) Formulation Composition (g kg 21 ) Barley Wheat Soya bean hipro Copra meal Tallow Molasses Soya oil Salt Dicalcium phosphate Limestone Minerals and vitamins Synthetic amino acids Lysine Methionine Chemical composition (g kg 21 ) DM Ash Fat Crude fibre Crude protein Lysine Methionine and cystine Threonine Calcium Phosphorus Digestible energy content (MJ kg 21 )a
T1 Control
T2 100 Barley
T3 200 Barley
T4 100 Least cost
T5 200 Least cost
354.3 300.0 251.0 0 30.0 30.0 10.0 3.5 6.0 9.8 2.5
254.3 300.0 251.0 100.0 30.0 30.0 10.0 3.5 6.0 9.8 2.5
154.3 300.0 251.0 200.0 30.0 30.0 10.0 3.5 6.0 9.8 2.5
265.0 300.0 246.9 100.0 24.2 30.0 10.0 3.5 5.1 10.0 2.5
176.9 300.0 242.0 200.0 17.3 30.0 10.0 3.5 4.2 10.9 2.5
2.0 0.9
2.0 0.9
2.0 0.9
2.0 0.8
2.0 0.7
884.5 54 60 43 195 10.8 6.2 7.5 6.6 5.5
876.0 58 69 49 209 11.1 6.4 7.8 6.6 5.4
870.5 62 77 55 231 11.2 6.6 8.2 6.9 5.6
878.5 50 60 49 206 11.0 6.2 7.6 6.6 5.5
872.2 54 61 56 213 11.0 6.3 7.6 6.6 5.5
13.85
14.05
14.25
13.93
13.97
a
The DE content of the diets was calculated using the estimated DE content of the copra meal obtained from the digestibility experiment while the DE value for the remainder of the ingredients were obtained from official feeding tables (Ministry of Agriculture, Fisheries and Food, 1991).
Estimated lean meat proportion (g kg 21 ) 5 655.4 2 13.498 3 probe fat (mm) 1 0.177 3 (probe fat, mm)2 1 0.719 3 muscle depth (mm)
2.3. Chemical analysis The chemical analysis of dry matter, crude protein and ash were carried out according to the AOAC (1980). The dry matter contents of the feeds and faeces were determined by oven drying at 558C for 72 h with forced air circulation. The dried concentrates and faeces were milled through a 1-mm screen (Christy and Norris hammer mill) and analysed for
ash by burning in a furnace at 6008C for 4 h, crude protein by the macro-Kjeldahl method (Kjeldahl N3 6.25), neutral detergent fibre (NDF) content by the method of Van Soest (1976), crude fibre by the Weende method (AOAC, 1980). Ether extract was determined using the 1043 Soxtec System HT6 as derived from the Soxlet method. The amino acid compositions of the diet were determined by the method of Iwaki et al. (1987).
2.4. Statistical analysis The data was analysed using least square procedures (Proc. GLM of the Statistical Analysis
J.V. O’ Doherty, M.P. McKeon / Livestock Production Science 67 (2000) 55 – 65
System [SAS, 1985] version 5.16). In the digestibility experiment, the data was analysed as a 3 (diets)3 2 (age) factorial design. The model was partitioned into the main effects of diet, age of pig, pig effect and the interaction of diet and age of pig. The individual pig served as the experimental unit. In the performance experiment, the overall effect of level of copra meal and method of formulation on pig performance and carcass characteristics were analysed as a 232 factorial. In addition orthogonal contrasts were made between the control and the four copra meal diets (T2, T3, T4 and T5), between the control and the 100 g copra meal kg 21 diets (T2 and T4) and between the control and the 200 g copra meal kg 21 diets (T3 and T5). The kill-out, back fat and lean meat were adjusted for slaughter weight by covariance analysis. The individual pen served as the experimental unit.
59
Table 3. There was a significant interaction in organic matter (OM), protein and energy digestibility between level of copra meal in the diet and age of pig (P,0.05). The pigs offered the 400 g copra meal kg 21 in the diet had a significantly higher OM, protein and energy digestibility (P,0.05) in the finisher stage than in the grower stage. However, age of pig had no effect on nutrient digestibility when the pigs were fed the control and 200 g copra meal kg 21 diets. Pigs offered the control diet had a significantly lower fibre digestibility than pigs offered the 200 and 400 g copra meal kg 21 diets (P,0.05). The nutrient digestibility coefficients and the DE content of the copra meal component of the diet are presented in Table 4. There was a tendency for the digestibility of the OM, protein and energy and the DE content of the copra meal to decrease as the level of copra meal in the test diet increased.
3.2. Performance experiment 3. Results Mean initial live weight was 39.9 kg (S.D.50.31) with no difference between treatments. During the experiment, two pigs were removed from their treatments (death and tail biting). The effect of dietary treatment on feed intake and DE intake is
3.1. Digestibility experiment The effects of diet and age of pig on apparent nutrient digestibility coefficients are presented in
Table 3 Effects of diet and age of pig on apparent nutrient digestibility coefficients of the diets (L.S.M.6S.E) Diet
S.E.
Control
Digestibility coefficients Organic matter Protein Neutral detergent fibre Energy a
200 g copra meal kg
21
400 g copra meal kg
21
Grower
Finisher
Grower
Finisher
Grower
Finisher
0.882 0.892 0.592 0.878
0.878 0.892 0.563 0.874
0.871 0.848 0.717 0.868
0.878 0.865 0.708 0.876
0.846 0.776 0.754 0.843
0.875 0.847 0.800 0.870
Significance Diet
0.008 0.012 0.022 0.006
* *** *** *
Age
Diet3Age
**
* * *
* P,0.05; ** P,0.01; *** P,0.001.
Table 4 Mean digestibility coefficients for organic matter, protein, energy and digestibile energy (DE) content (MJ kg 21 DM) of copra meal Copra meal (g kg 21 )
Organic matter
Protein
Energy
DE content
200 400
87.9 84.8
84.6 74.8
85.5 82.8
16.4 15.7
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Table 5 Effect of dietary treatment on feed intake and digestible energy intake (L.S.M.6S.E.) Treatments
S.E.
Significance Contrast a
1 Control
2 100 Barley
3 200 Barley
4 100 Least cost
5 200 Least cost
Grower phase (0–28 days) Intake (kg day 21 ) Digestible energy (MJ day 21 )
1.95 26.9
1.91 26.8
1.79 26.5
1.92 26.7
1.88 26.3
0.066 0.93
Finisher phase (28–61 days) Intake (kg day 21 ) Digestible energy (MJ day 21 )
2.88 39.9
2.73 38.4
2.52 35.8
2.69 37.5
2.63 36.7
0.077 1.09
** *
2.32 32.6
2.15 30.7
2.31 32.4
2.26 31.5
0.059 0.84
** *
Copra inclusion (g kg Formulation
21
)
Combined grower–finisher phase (0–61 days) Intake (kg day 21 ) 2.42 Digestible energy (MJ day 21 ) 33.5
Contrast b
Contrast c
Contrast d
*
*
*** **
*
** *
*
a
Contrast between the control and the four diets (control vs. T2, T3, T4 and T5). Contrast between the control and the 100 g copra meal kg 21 diets (control vs. T2 and T4). c Contrast between the control and the 200 g copra meal kg 21 diets (control vs. T3 and T5). d Contrast between the 100 g kg 21 and the 200 g copra meal kg 21 diets (T2 and T4 vs. T3 and T5). * P,0.05; ** P,0.01; *** P,0.001. b
presented in Table 5 while the effect of treatment on growth rate, feed and DE conversion ratios and live weight is presented in Table 6. The DE content of the diets was calculated using the estimated DE content of the copra meal obtained from the digestibility experiment while the DE values for the remainder of the ingredients were obtained from official feeding tables (Ministry of Agriculture, Fisheries and Food, 1991). Experimental period had no effect on any variable measured. The inclusion of copra meal in the diet decreased feed intake during both the finisher period (P,0.01) and the grower–finisher period (P,0.01) compared to the control diet. Pigs offered the control diet had a significantly higher feed intake than the pigs offered the 100 g (P,0.05) and 200 g copra meal kg 21 (P,0.001) in the diet during the finisher period. Pigs offered the 100 g copra meal kg 21 had a higher intake than the pigs offered the 200 g copra meal kg 21 in the diet (P,0.05) during both the finisher period and grower–finisher period. The inclusion of copra meal in the diet decreased DE intake during the finisher period (P,0.05) and during the grower–finisher period (P,0.05) compared to the control diet. Pigs offered the control diet
had a higher DE intake than the pigs offered the 200 g copra meal kg 21 in the diet during both the finisher period (P,0.01) and combined grower and finisher period (P,0.05). There was a significant interaction (P,0.01) in growth rate between level of copra meal inclusion and method of formulation during the finisher and combined grower and finisher period. As the level of copra meal in the diet increased in the least cost formulation, growth rate increased (P,0.05). However, as the level of copra meal in the diet increased in the barley substitution formulation, growth rate decreased (P,0.05). Pigs offered the control had a higher live weight gain (P,0.05) than the pigs offered the 200 g copra meal kg 21 during the grower period. The pig live weights at the end of the grower period were lighter for the pigs fed the 200 g kg 21 copra meal in the diet (P,0.05) and this reflected the trends in growth rate. The inclusion of copra meal in the diet improved food conversion ratio (FCR) during the finisher and combined grower–finisher periods (P,0.05) compared to the control diet. Pigs offered the 200 g copra meal kg 21 had a significantly better FCR than the control and the 100 g kg 21 copra meal fed pigs
J.V. O’ Doherty, M.P. McKeon / Livestock Production Science 67 (2000) 55 – 65
61
Table 6 Effect of dietary treatment on pig performance (L.S.M.6S.E.) Treatments
S.E. 2 10 Barley
3 20 Barley
4 10 Least cost
5 20 Least cost
Initial weight (kg)
40.0
40.1
39.5
39.6
40.2
0.85
Grower phase (0–28 days) Live weight gain (kg day 21 ) Food conversion ratio (g g 21 ) DE conversion ratio (MJ kg 21 )f Live weight at 28 days
0.824 2.47 33.1 63.4
0.833 2.39 32.4 63.7
0.781 2.43 33.5 61.3
0.799 2.50 33.8 62.0
0.809 2.49 33.6 63.1
0.025 0.081 1.12 1.43
Finisher phase (28–61 days) Live weight gain (kg day 21 ) Food conversion ratio (g g 21 ) DE conversion ratio (MJ kg 21 )f Live weight at 61 days
0.940 2.77 42.4 94.2
0.929 2.75 42.3 94.0
0.899 2.55 40.1 90.7
0.916 2.67 41.0 92.0
0.980 2.47 38.4 95.1
0.026 0.071 1.08 1.61
Combined grower–finisher phase (0–61 days) Live weight gain (kg day 21 ) 0.886 0.884 Food conversion ratio (g g 21 ) 2.63 2.57 DE conversion ratio (MJ kg 21 )f 37.9 37.4
0.843 2.50 36.9
0.862 2.59 37.5
0.897 2.48 36.1
0.020 0.054 0.79
21
Copra inclusion (g kg ) Formulation
Contrast 1a
1 Control
2b
3c
4d
5e
*
* ** *
** *
*
*
* *
**
a
Contrast between the control and the four diets (control vs. T2, T3, T4 and T5). Contrast between the control and the 100 g copra meal kg 21 diets (control vs. T2 and T4). c Contrast between the control and the 200 g copra meal kg 21 diets (control vs. T3 and T5). d Contrast between the 100 g and the 200 g copra meal kg 21 diets (T2 and T4 vs. T3 and T5). e Interaction between method of formulation and copra meal level. f DE conversion ratio: digestible energy conversion ratio (MJ kg 21 live weight). * P,0.05; ** P,0.01; *** P,0.001. b
(P,0.05) during the finisher period. Pigs fed the 200 g copra meal kg 21 also had a significantly better DE conversion ratio than the control and 100 g copra meal kg 21 during the finisher period (P,0.05). The effect of diet on carcass characteristics is presented in Table 7. The inclusion of copra meal in the diet decreased carcass weight (P,0.01) and kill out proportion (P,0.01). Pigs offered the control diet and the 100 g copra meal kg 21 had significantly higher carcass weight (P,0.01) and kill out proportion (P,0.001) than the pigs offered the 200 g copra meal kg 21 diet. Pigs offered copra meal formulated on a least cost basis had a significantly heavier carcass weight (72.2 vs. 71.5 kg, S.E.M. 0.76: P, 0.05) and a lower killing out proportion (72.2 vs. 72.9, S.E.M 0.30: P,0.05) than the pigs fed copra meal as a direct replacement for barley. Dietary treatment had no effect on lean meat or back fat
depth. Pigs offered the control diet had a significantly better carcass average daily gain (P,0.05) than the pigs offered the copra meal diets. Carcass FCR and carcass DE conversion ratio were unaffected by dietary treatment.
4. Discussion The OM, protein and energy digestibility coefficients decreased as the level of copra meal in the diet increased. The nutrient digestibility of the diets decreased with increased neutral detergent fibre in the diet. Similar results were reported by Noblet and Perez (1993) who observed that a high level of fibre in the diet resulted in some of the OM, protein and energy in the diet becoming unavailable. This may be due to fibre hindering the access of digestive
J.V. O’ Doherty, M.P. McKeon / Livestock Production Science 67 (2000) 55 – 65
62
Table 7 Effect of dietary treatment on carcass performance (L.S.M.6S.E.) Treatments
Copra inclusion (g kg Formulation
21
)
Carcass characteristics Slaughter weight (kg) Cold carcass weight (kg) Kill out (g kg 21 ) Backfat P2 (mm) Lean meat (g kg 21 ) Carcase gain (g day 21 ) Carcase FCR (g g 21 ) Carcase DE conversion ratio (MJ kg 21 )e
S.E.
1 Control
2 100 Barley
3 200 Barley
4 100 Least cost
5 200 Least cost
97.9 72.1 734.0 13.3 540.0 0.695 3.50 51.6
99.4 73.8 731.0 13.0 544.4 0.704 3.33 51.3
95.4 69.2 727.0 11.9 556.0 0.656 3.29 51.2
96.0 72.5 731.0 12.2 552.0 0.709 3.28 51.4
99.4 72.0 713.0 12.9 548.0 0.702 3.26 50.1
Contrast 1a
1.29 1.14 0.40 0.89 5.20 0.014 0.097 1.08
2b
3c
4d
** **
*** ***
** **
*
*
a
Contrast between the control and the four diets (control vs. T2, T3, T4 and T5). Contrast between the control and the 100 g copra meal kg 21 diets (control vs. T2 and T4). c Contrast between the control and the 200 g copra meal kg 21 diets (control vs. T3 and T5). d Contrast between the 100 g and the 200 g copra meal kg 21 diets (T2 and T4 vs. T3 and T5). e Carcass DE conversion ratio: Digestible energy per kg carcass (MJ kg 21 carcass weight). * P,0.05; ** P,0.01; *** P,0.001. b
enzymes to the cell contents (Bach-Knudsen et al., 1993). Fibre has been observed to increase the digesta rate of passage (Low, 1993) and this may reduce the time available to the digestive enzymes to act on the other substrates. The current experiment shows that the nutrient digestibility of the diets can vary with age and bodyweight of the animals. However, this variation in digestibility is ingredient related. The 400 g copra meal kg 21 diet was digested better by the finisher pig than the grower pig, probably due to a better developed hind gut fermentation. The depressive effect of fibre is more pronounced in growing pigs than finishing pigs, particularly at high NDF content. Similar results were reported by Noblet et al. (1994) who stated that fibrous feeds were better digested by older animals such as sows due to their better developed hind gut fermentation and lower feeding level relative to maintenance. Due to these factors, Noblet and Bourdon (1997) showed that the DE content of diets for sows was 4 MJ higher for high fibre by-products and 0.2–0.5 MJ for cereals than when compared to younger pigs. The DE content of copra meal when estimated using 200 g kg 21 copra meal in the test diet was very similar to the 15.5 MJ DE kg 21 DM determined by
Thorne (1986) and Dore (1999) which had a residual oil content of 91 g kg 21 similar to the oil content of the copra meal (93 g kg 21 ) used in the current experiment.
4.1. Performance experiment During the grower–finisher period, pigs offered increasing levels of copra meal in the diet had lower intakes than the control fed pigs. This reduction in intake may be due to the increasing level of energy and fibre in the diet, both of which increase as the level of copra meal in the diet increases. Reductions in voluntary feed intake are often responses to changes in dietary nutrient balance such as increased energy level (Cole et al., 1972; Cole and Chadd, 1989) or imbalances in the dietary amino acid supply (Harper et al., 1970). Thorne et al. (1992) observed that increasing dietary copra meal decreased feed intake also. These authors attributed this to increased fibre in the diet hence reducing intake through its effect on gut fill. The reduced feed intake with copra meal inclusion could also be due to a high arginine content (Thorne, 1986). There may also be a palatability problem with high inclusion levels of copra meal.
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The pigs offered the control diet had a higher live weight gain than the pigs offered the 200 g copra meal kg 21 during the grower period. However, there was no difference in growth rate during the finisher period and live weight at the end of the experiment was similar for the control, 100 and 200 g copra meal kg 21 diets. This was surprising since Thorne et al. (1988) found that there was a linear reduction in daily gain as the level of copra meal in the diet increased. However, in the current experiment, careful attention was given to the amino acid balance and all least cost diets were formulated to an ideal protein (Close, 1994). However, the daily live weight gain of the pigs offered copra meal may have been over estimated. On a carcass basis the pigs fed the control diet had a better carcass daily gain than the pigs fed the 200 g copra meal kg 21 . These pigs also had a higher carcass weight and kill out proportion than the pigs offered the copra meal diets. The lower kill out proportion of the 200 g copra meal kg 21 fed pigs was due to the negative effect of the dietary fibre. The low kill out proportion subsequently reduced cold carcass weight in the 200 g copra meal kg 21 fed pigs. Fibre extends the gut thereby reducing the kill out proportion. This agrees with Jorgensen et al. (1996) who stated that a high fibre diet would increase the length and weight of the intestinal tract. There was also a depression in growth rate in the pigs offered the 200 g copra meal kg 21 as a direct replacement for barley. This decrease in growth rate may be due to a number of reasons These are decreased feed intake and excess fat and protein. This depression in growth rate may be due to the lower feed intake with the 200 g copra meal kg 21 substituted barley diet. A number of studies have found that the pig will regulate voluntary intake according to the energy density of the diet (Cole et al., 1972; Cole and Chadd, 1989). In the 200 g copra meal kg 21 substituted barley diet, feed intake decreased as the energy concentration of the diet increased. However, in terms of total daily energy intake, compensation was not complete. The numerical tendency for a decline in backfat thickness observed with this diet is consistent with a reduction in DE intake. The depression in intake would also result in these pigs having lower lysine intakes during the grower
63
and finisher periods. The digestibility experiment showed that as the level of copra meal in the diet increased, protein digestibility decreased. The decrease in protein digestibility would have a greater effect at lower feed intake, thereby decreasing protein availability and ultimately amino acid intake and availability. If protein is below requirements, nitrogen deposition rate will be reduced (Rao and McCracken, 1991). The increased fat content of this diet may also hinder fibre digestibility. Kavanagh (1998) reported lower digestibility of fibre in diets supplemented with high levels of fat. There is evidence from ruminants that supplementary fat in the diet results in an inhibition of rumen microflora (Brooks et al., 1954). It is possible that this may also apply to the large intestine of the pig. Bakker (1996) found that adding animal fat to fibrous diets had a negative effect on fermentation in the dietary tract of the pig. Fibre is one of the primary substrates fermented in the large intestine (Varel, 1987) and Dierick et al. (1989) suggest that volatile fatty acids make a small but important contribution to the energy supply of the pig. The control fed pigs had the worst FCR while 200 g copra meal kg 21 in the diet had the best FCR. The poorer FCR of the control fed pigs, especially during the finisher period is probably due to these pigs having too high an ad libitum feed intake. Campbell et al. (1985) found that the FCR improved with each increase in energy intake up to 33 MJ DE per day in similar live weight pigs. In the present experiment, there was a marked change in the effects of feeding rate on FCR when DE intake exceeded 35 MJ day 21 . The numerical tendency for an increase in backfat thickness observed with this diet is consistent with the DE intake. The FCR may also be underestimated in the pigs fed the 200 g copra meal kg 21 in the diet, as a result of the increased gut fill which will influence live weight gain. However, when efficiency was measured in terms of the amount of the DE required per kg carcass, there was no difference in efficiency between the control, 100 and 200 g copra meal kg 21 diets. It can be concluded from the in vivo digestibility studies that increasing levels of copra meal in the diet will lower nutrient digestibility. However, copra
64
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meal is an excellent source of energy for pigs and the DE values obtained in this study are similar to other previously quoted values. Careful consideration must be given to inclusion of copra meal in pig diets. Formulating diets on the basis of least cost favours the inclusion of copra meal. The inclusion of copra meal at 200 g kg 21 as a replacement for barley lowers pig performance and should be avoided. The inclusion of 200 g kg 21 copra meal on the basis of least cost does not affect performance but careful consideration must be given to intake and killing out proportion. High levels of copra meal should be favourable for heavy pigs and sows.
Acknowledgements We are grateful to James Callan and Bernie Flynn for assistance with laboratory analysis and to HKM Milling Ltd. for financial assistance.
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