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The effect of mechanical treatment on the nutritive value of high-moisture barley and the performance of growing-finishing pigs
Animal Feed Science and Technology, 24 (1989) 121-128
121
Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
The Effect of M e c h a n i c a l T r e a t m e n t on the N u t r i t i v e Value of H i g h - m o i s t u r e B a r l e y and the P e r f o r m a n c e of G r o w i n g - F i n i s h i n g P i g s ROBERT HLODVERSSON*
Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, S-750 07 Uppsala (Sweden) (Received 12 December 1986; accepted for publication 18 July 1988)
ABSTRACT H15dversson, R., 1989. The effect of mechanical treatment on the nutritive value of high-moisture barley and the performance of growing-finishing pigs. Anim. Feed Sci. Technol., 24: 121-128. The effect of processing a diet based on high-moisture barley (24% moisture) was investigated in a digestibility study with eight growing pigs (24-51 kg live weight) using a 4 × 4 Latin square design and in a growth experiment with 120 growing-finishing pigs. Physical processing of the diet was by hammer mill (Treatment 1 ); by whole-grain pelleting through 3.l-ram and 3.9-mm dies (Treatments 2 and 3, respectively); by cold rolling prior to pelleting through 4.8-mm die (Treatment 4). Rolling the barley prior to pelleting significantly improved (P < 0.05) the digestibilityof crude protein and energy, and the metabolizable energy content of the diet. There were no differences between the treatments concerning nitrogen balance, biological value, net protein utilization or efficiency of nitrogen retention. The feeding trial showed that the pigs on Treatment 4 grew significantly faster than those on Treatment 3 and non-significantly faster than those on Treatments 1 and 2. No differences were found between the treatments in feed conversion ratio or carcass quality. It can be concluded from the experiments that comparable results can be obtained by wholegrain pelleting and grinding as long as the pellet size does not exceed 3.1 mm in diameter. Wholegrain pelleting with pellets larger than 3.0 mm in diameter (3.9 mm) makes it necessary to roll or grind the barley before pelleting; otherwise, the digestibility of nutrients and the performance of the pigs are significantly decreased.
INTRODUCTION The effect of processing methods on the feeding value of moist cereals has been investigated in several Swedish experiments. Simonsson and GSransson (1982) did not find any differences in digestibility or animal performance bet w e e n m o i s t b a r l e y m i l l e d , r o l l e d o r p e l l e t e d a s w h o l e g r a i n (3.0 m m d i a m e t e r ). *Correspondence address: Ranmsoknathomustam HF, Stangarhyl 7, Box 10102, 110 Reykjavik, Iceland.
0377-8401/89/$03.50
© 1989 Elsevier Science Publishers B.V.
122 G5ransson and Ogle (1985) processed moist cereals (23-30% moisture) by cutter (2.5-mm screen), or hammer mill (3.5 m m diameter) or by cold rolling through a double smooth-roller mill (2.5 m m gap). The treatments did not significantly affect the digestibility of the nutrients or the performance of the pigs~ On the other hand, Ogle and Lund (1985) noted significantly higher daily gains and better feed conversion ratios for pigs fed on moist barley milled rather t h a n pelleted as whole-grain pellets (3.9 and 4.8 m m diameter). The purpose of the experiments reported here was to investigate the effect of processing methods (milled; whole-grain pelleting to 3.1- and 3.9-mm pellets; rolled before pelleting to 4.8-mm pellets), on the nutritive value of highmoisture barley and on the performance of growing-finishing pigs. MATERIALSAND METHODS
Barley The barley was grown in 1985 at the Swedish University of Agricultural Sciences experimental farm, Uppsala. The moisture content (MC) of the barley at harvest was 24.3%. The whole grain barley was stored in two airtight fibre-glass silos (35 m 3 each).
Processing of the diets Unloading of the silos was performed once per week after the beginning of the growth trial (Trial I) by means of augers connected to the conical lower end of the silos. The augers were kept airtight between unloadings. The wholegrain barley and the concentrate used were mixed in a conventional mixer. The proportion of barley to concentrate was adjusted periodically according to the variations in the barley moisture content, so as to give a final diet with a nutrient composition which corresponded, on a dry matter basis, to a commercial growing-fattening diet. The concentrate used was pelleted through a 5m m matrix and the proportion of soya-bean meal was 0.728, fish meal 0.097, dicalcium phosphate 0.073, ground limestone 0.034, sodium chloride 0.019, and vitamin and mineral supplement 0.049. Physical processing of the diets was as follows: Treatment 1: hammer mill (3.5-mm screen); Treatment 2: whole-grain pelleted through a 3.1 m m die; T r e a t m e n t 3: whole-grain pelleted through a 3.9 m m die; Treatment 4: rolled prior to pelleting through a 4.8 m m die. Each treatment refers to the diet with the same number. Analysis of the diets is given in Table 1.
123 TABLE 1 Analysisof the diets used in Trials I and II Trial I
Dry matter (g kg- 1) Crude protein (g kg-lDM) Ash (g kg-~DM) Gross energy (MJ kg-lDM) ME (MJ kg-~DM)a
Trial II
Mean
No. of samples
Standard deviation
Mean
No. of samples
Standard deviation
785
64
1.5
810
16
1.8
203
28
2.4
198
16
0.8
61
12
0.7
57
16
0.3
6
0.1
18.2
4
0.1
-
13.7
18.1 13.7
-
-
aEstimatedmetabolizableenergycontent.
Experimental design and procedure In Trial I, 120 Yorkshire >< Swedish Landrace pigs were randomly allocated to the four t r e a t m e n t groups, each of the six replicates consisting of five individually fed pigs, balanced for initial live weight and sex. The animals were weighed every second week and slaughtered at ~ 104 kg live weight. The quality of the carcasses was assessed as meat in carcass (%). In the digestibility study (Trial II), eight Yorkshire X Swedish Landrace male pigs of known genetic background were used. The live weight range of the pigs was 24.0-29.1~ 34.6-35.4, 39.5-44.2 and 47.2-51.1 kg during the four collection periods, respectively. The experimental design was a 4 X 4 L a t i n square with two replicates. The animals were randomly assigned to t r e a t m e n t s in the first experimental period. The experimental diets were given for a preliminary period of 9 days. During the first 7 days of each preliminary period, the pigs were penned together, but they were kept in individual metabolic cages for the last 2 days. This was followed by a 5-day collection period, during which faeces and urine were quantitatively collected once a day. Urine was collected into 35 ml of 10% H2SO4. After collection, one-quarter of the total a m o u n t of urine was placed in a refrigerator at + 4 ° C. The faeces were frozen at - 25 ° C. Faeces from each period were thawed overnight and mixed. A sample of ~ 220 g wet faeces was oven dried at 65 °C for 24 h. After drying, the samples were ground in a Wiley mill to pass through a l - r a m screen.
124
Feeding The pigs were fed twice daily and water was given ad libitum. In Trial I, the pigs were fed according to Swedish recommendations with increasing feed allowance to 60 kg live weight (Andersson, 1985). In Trial II, the feeding level was based on an estimated daily weight gain of ~ 540 g. During each collection period, the daily feed consumption per animal was kept constant (1.40, 1.80, 2.00 and 2.40 kg for Periods 1, 2, 3 and 4, respectively) which supplied each animal with ~ 17.7 g crude protein per kg metabolic weight (W °'75) per day.
Chemical analyses In Trial I, all feed samples were dried in an oven at 105°C for 16 h and analysed for crude protein (CP) and ash according to the methods of A.O.A.C. (1977). The gross energy content (GE) was determined by bomb calorimetry. In Trial II, samples of feed and faeces were analysed as described for Trial I. Urine N was determined in 5-ml samples. Energy, in 50-ml freeze-dried urine samples, was determined with a Gallenkamp adiabatic calorimeter (CB-100).
Statistical methods For the growth trial (Trial I), the results were treated by analysis of variance using the general linear model (GLM) procedure in the Statistical Analysis System (SAS) described by the SAS Institute (1982). Average values for production results and carcass characteristics are given as least squares means and Duncan's multiple range test was used to find significant differences (P < 0.05) between the variables. In Trial II, statistical analyses were performed using the analysis of variance (ANOVA) procedure in the Statistical Analysis System (SAS) described by the SAS Institute Inc. (1982). The following model was used: Y = ABCA*B where Y -- the dependent variable; A, B and C the effects of diet, period and animal, respectively; A*B = interactions between diet and period. RESULTS
Trial I The results from Trial I are given in Table 2. Treatment 4 resulted in significantly greater rates of live-weight gain than Treatment 3. It also took ~ 5 days longer for the pigs on Treatment 3 to reach slaughter weight than for pigs on Treatment 4. No significant differences were found between the treatments in feed conversion or carcass quality.
125 TABLE 2 The effect of treatment on performance, feed conversion and carcass quality Treatment
Live-weight gain (91 day) (g) No. of days to slaughter weight Feed conversion (kg feed/kg gain) Meat in carcass (%)
1
2
3
4
749 ab 108~b 3.4 57.8
715 ab 107ab 3.3 58.6
735 b 109a 3.4 57.8
771 a 104b 3.2 57.3
Means in the same row with common superscripts do not differ significantly (P < 0.05).
Trial H
Since no interactions were found between diet and period, these effects were discarded from the model. A summary of ANOVA for each dependent variable for the four diets is given in Table 3. According to the F-test, the model as a whole (adjusted for the mean) accounted well for the behaviour of the dependent variable, except for the efficiency of N retention, net protein utilization (NPU) and biological value (BV). Additionally, R 2 is high, showing that the
TABLE 3 Summary of the analysis of variance for the digestibility and nitrogen balance trial Dependent variable Diet digestibility coefficient Organic matter Crude protein Energy Nitrogen balance (g day -1) Urinary N N retained Efficiency of N retention Of ingested N Of digested N Biological value Net protein utilization DE content (MJ k g - i D M ) ME content (MJ kg- 1DM) aCV = coefficient of variation (%)
Mean 0.842 0.796 0.815
CVa
R2
F-value
1.3 2.2 1.5
0.684 0.833 0.779
3.0** 6.9*** 4.9***
9.4 11.5
0.910 0.809
14.1"** 5.9***
0.387 0.486
10.7 9.8
0.453 0.483
1.2N s 1.3 Ns
0.571 0.465 14.7 14.1
8.1 9.0 1.5 1.5
0.456 0.435 0.835 0.832
1.2Ns 1.1Ns 7.0*** 6.9***
16.7 15.7
126 TABLE 4 The effect of treatment on the apparent digestibility of nutrients, DE and ME contents of the diets Treatment 1 Digestibility coefficient Organic matter Crude protein Energy DE content (MJ k g - l D M ) ME content (MJ k g - l D M )
0.842 0.7945 0.8115 14.75 14.15
2
3 0.838 0.7855 0.8095
14.4 ° 13.85
4 0.841 0.7885 0.8145
14.5be 13.95
F-value 0.849 0.817 a 0.827 ~
1.4Ns 5.6** 3.4*
15.0 a 14.4a
12.6"** 12.5"**
Means in the same row with common superscripts do not differ significantly (P < 0.05) TABLE 5 The effect of period on the apparent digestibility coefficients of nutrients and energy, and DE and ME contents of the diets Period
Digestibility coefficients Organic matter Crude protein Energy DE content (MJ kg1 DM ME content (MJ kg -1 DM)
I
II
III
IV
F-value
0.8305 0.764 c 0.7965 14.35 13.75
0.840 a5 0.7905 0.814 a 14.6 ~ 14.1 ~
0.849 a 0.813 a 0.824 ~ 14.8a 14.2~
0.851 a 0.817 a 0.826 a 14.9 ~ 14.2 a
6.0** 15.0"** 9.7*** 9.,6"** 9.7***
Means in the same row with common superscripts do not differ significantly (P < 0.05). model fits well to the data. The variation (CV) in the population especially for variables not connected to the protein utilization.
is s m a l l ,
The effects of diets Apparent digestibility coefficients of nutrients and energy, and the digestible energy (DE) and metabolizable energy (ME) contents of the diets are g i v e n i n T a b l e 4. T h e t r e a t m e n t s h a d s i g n i f i c a n t e f f e c t s o n t h e d e p e n d e n t v a r i ables (P < 0.05), except for the digestibility of organic matter. The digestibility coefficients for protein and energy for Treatment 4 (rolled before pelleted), and the DE and ME contents of the diet were significantly higher than
127
in other treatments. No significant differences were found between the diets in nitrogen balance, efficiency of N retention, BV and NPU.
The effects of animals and periods The effect of animal on the dependent variables was seldom significant and only in a few cases was there a difference between animals. On the other hand, the effect of period was highly significant and considerable differences were found between periods, especially between the first period and the others, for the digestibility coefficients of nutrients and for DE and ME contents of the diets (Table 5). DISCUSSION
The results from the feeding trial show that whole-grain pelleting to a greater pellet size than ~ 3.0 m m reduced the live-weight gain of the pigs. These results are in good agreement with those of Ogle and Lund (1985). The best growth response was obtained when the diet was subjected to two processes, i.e., rolling before pelleting (Treatment 4). This processing method resulted in significantly higher daily live-weight gain of the pigs than wholegrain pelleting to 3.9 m m pellets. On the other hand, the differences in daily live-weight gain between T r e a t m e n t 4 and Treatments 1 and 2 were not significant. Choosing between these treatments is, therefore more an economic question than a question of better response. The results from the digestibility study confirm the results from the feeding experiment. The most efficient utilization was obtained for the diet which was subjected to the two processes (Treatment 4). Both the digestibility of CP and energy, and the ME content of the diet, were significantly higher for this treatm e n t than for other treatments. The digestibility coefficients of nutrients and energy, and the ME content of the diets, were significantly lower in the first period than in the others. The pigs only weighed between 24.0 and 29.1 kg in the first period, and it is assumed that the digestive systems of the animals were not fully developed at that time. Similar effects of period on digestibility have been reported by several workers (Christison and Parra de Solano, 1982; Fernandez et. al., 1986; H15dversson, 1987). REFERENCES Andersson, K., 1985. SLU-normen - en ny utfodringsnorm f6r slaktsvin. (The SLU-standard - a new feeding standard for pigs. ) Swedish University of Agricultural Sciences, Research Information Centre, Report No. 67, pp. 6-13. Association of Official Analytical Chemists, 1977. Official Methods of Analysis. A.O.A.C., Washington, DC.
128 Christison, G.I. and Parra de Solano, N.M., 1982. Utilization of protein from peas, barley, buttermilk powder and soyabean meal by early weaned pigs. Can. J. Anim. Sci., 62: 899-905. Fernandez, J.A., JSrgensen, H. and Just, A., 1986, Comparative digestibility experiments with growing pigs and adult sows. Anim. Prod., 43: 127-132. GSransson, L. and Ogle, R.B., 1985. Anaerobically stored high moisture cereals for growing pigs. Anim. Feed Sci. Technol., 12: 159-169. H15dversson, R., 1987. The nutritive value of white- and dark-flowered cultivars of pea for growing-finishing pigs. Anim. Feed Sci. Technol., 17: 245-252. Ogle, R.B. and Lund, S., 1985. Helk~irnspelletter av gast~itt lagrad spannm~l och ~ t e r som foder till slaktsvin. (Whole grain pelleted cereals and peas as a feed for growing-finishing pigs.) Swedish University of Agricultural Sciences, Research Information Centre, Report No. 67, pp. 1-5. SAS Institute Inc., 1982. SAS User's Guide: Statistics, SAS Institute Cary, NC, 584 pp. Simonsson, A. and G6ransson, L., 1982. Otorkad spannm~l som svinfoder. (Undried cereals as a pig feed.) Aktuellt fr~n lantbruksuniversitetet 310, Uppsala.
121
Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
The Effect of M e c h a n i c a l T r e a t m e n t on the N u t r i t i v e Value of H i g h - m o i s t u r e B a r l e y and the P e r f o r m a n c e of G r o w i n g - F i n i s h i n g P i g s ROBERT HLODVERSSON*
Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, S-750 07 Uppsala (Sweden) (Received 12 December 1986; accepted for publication 18 July 1988)
ABSTRACT H15dversson, R., 1989. The effect of mechanical treatment on the nutritive value of high-moisture barley and the performance of growing-finishing pigs. Anim. Feed Sci. Technol., 24: 121-128. The effect of processing a diet based on high-moisture barley (24% moisture) was investigated in a digestibility study with eight growing pigs (24-51 kg live weight) using a 4 × 4 Latin square design and in a growth experiment with 120 growing-finishing pigs. Physical processing of the diet was by hammer mill (Treatment 1 ); by whole-grain pelleting through 3.l-ram and 3.9-mm dies (Treatments 2 and 3, respectively); by cold rolling prior to pelleting through 4.8-mm die (Treatment 4). Rolling the barley prior to pelleting significantly improved (P < 0.05) the digestibilityof crude protein and energy, and the metabolizable energy content of the diet. There were no differences between the treatments concerning nitrogen balance, biological value, net protein utilization or efficiency of nitrogen retention. The feeding trial showed that the pigs on Treatment 4 grew significantly faster than those on Treatment 3 and non-significantly faster than those on Treatments 1 and 2. No differences were found between the treatments in feed conversion ratio or carcass quality. It can be concluded from the experiments that comparable results can be obtained by wholegrain pelleting and grinding as long as the pellet size does not exceed 3.1 mm in diameter. Wholegrain pelleting with pellets larger than 3.0 mm in diameter (3.9 mm) makes it necessary to roll or grind the barley before pelleting; otherwise, the digestibility of nutrients and the performance of the pigs are significantly decreased.
INTRODUCTION The effect of processing methods on the feeding value of moist cereals has been investigated in several Swedish experiments. Simonsson and GSransson (1982) did not find any differences in digestibility or animal performance bet w e e n m o i s t b a r l e y m i l l e d , r o l l e d o r p e l l e t e d a s w h o l e g r a i n (3.0 m m d i a m e t e r ). *Correspondence address: Ranmsoknathomustam HF, Stangarhyl 7, Box 10102, 110 Reykjavik, Iceland.
0377-8401/89/$03.50
© 1989 Elsevier Science Publishers B.V.
122 G5ransson and Ogle (1985) processed moist cereals (23-30% moisture) by cutter (2.5-mm screen), or hammer mill (3.5 m m diameter) or by cold rolling through a double smooth-roller mill (2.5 m m gap). The treatments did not significantly affect the digestibility of the nutrients or the performance of the pigs~ On the other hand, Ogle and Lund (1985) noted significantly higher daily gains and better feed conversion ratios for pigs fed on moist barley milled rather t h a n pelleted as whole-grain pellets (3.9 and 4.8 m m diameter). The purpose of the experiments reported here was to investigate the effect of processing methods (milled; whole-grain pelleting to 3.1- and 3.9-mm pellets; rolled before pelleting to 4.8-mm pellets), on the nutritive value of highmoisture barley and on the performance of growing-finishing pigs. MATERIALSAND METHODS
Barley The barley was grown in 1985 at the Swedish University of Agricultural Sciences experimental farm, Uppsala. The moisture content (MC) of the barley at harvest was 24.3%. The whole grain barley was stored in two airtight fibre-glass silos (35 m 3 each).
Processing of the diets Unloading of the silos was performed once per week after the beginning of the growth trial (Trial I) by means of augers connected to the conical lower end of the silos. The augers were kept airtight between unloadings. The wholegrain barley and the concentrate used were mixed in a conventional mixer. The proportion of barley to concentrate was adjusted periodically according to the variations in the barley moisture content, so as to give a final diet with a nutrient composition which corresponded, on a dry matter basis, to a commercial growing-fattening diet. The concentrate used was pelleted through a 5m m matrix and the proportion of soya-bean meal was 0.728, fish meal 0.097, dicalcium phosphate 0.073, ground limestone 0.034, sodium chloride 0.019, and vitamin and mineral supplement 0.049. Physical processing of the diets was as follows: Treatment 1: hammer mill (3.5-mm screen); Treatment 2: whole-grain pelleted through a 3.1 m m die; T r e a t m e n t 3: whole-grain pelleted through a 3.9 m m die; Treatment 4: rolled prior to pelleting through a 4.8 m m die. Each treatment refers to the diet with the same number. Analysis of the diets is given in Table 1.
123 TABLE 1 Analysisof the diets used in Trials I and II Trial I
Dry matter (g kg- 1) Crude protein (g kg-lDM) Ash (g kg-~DM) Gross energy (MJ kg-lDM) ME (MJ kg-~DM)a
Trial II
Mean
No. of samples
Standard deviation
Mean
No. of samples
Standard deviation
785
64
1.5
810
16
1.8
203
28
2.4
198
16
0.8
61
12
0.7
57
16
0.3
6
0.1
18.2
4
0.1
-
13.7
18.1 13.7
-
-
aEstimatedmetabolizableenergycontent.
Experimental design and procedure In Trial I, 120 Yorkshire >< Swedish Landrace pigs were randomly allocated to the four t r e a t m e n t groups, each of the six replicates consisting of five individually fed pigs, balanced for initial live weight and sex. The animals were weighed every second week and slaughtered at ~ 104 kg live weight. The quality of the carcasses was assessed as meat in carcass (%). In the digestibility study (Trial II), eight Yorkshire X Swedish Landrace male pigs of known genetic background were used. The live weight range of the pigs was 24.0-29.1~ 34.6-35.4, 39.5-44.2 and 47.2-51.1 kg during the four collection periods, respectively. The experimental design was a 4 X 4 L a t i n square with two replicates. The animals were randomly assigned to t r e a t m e n t s in the first experimental period. The experimental diets were given for a preliminary period of 9 days. During the first 7 days of each preliminary period, the pigs were penned together, but they were kept in individual metabolic cages for the last 2 days. This was followed by a 5-day collection period, during which faeces and urine were quantitatively collected once a day. Urine was collected into 35 ml of 10% H2SO4. After collection, one-quarter of the total a m o u n t of urine was placed in a refrigerator at + 4 ° C. The faeces were frozen at - 25 ° C. Faeces from each period were thawed overnight and mixed. A sample of ~ 220 g wet faeces was oven dried at 65 °C for 24 h. After drying, the samples were ground in a Wiley mill to pass through a l - r a m screen.
124
Feeding The pigs were fed twice daily and water was given ad libitum. In Trial I, the pigs were fed according to Swedish recommendations with increasing feed allowance to 60 kg live weight (Andersson, 1985). In Trial II, the feeding level was based on an estimated daily weight gain of ~ 540 g. During each collection period, the daily feed consumption per animal was kept constant (1.40, 1.80, 2.00 and 2.40 kg for Periods 1, 2, 3 and 4, respectively) which supplied each animal with ~ 17.7 g crude protein per kg metabolic weight (W °'75) per day.
Chemical analyses In Trial I, all feed samples were dried in an oven at 105°C for 16 h and analysed for crude protein (CP) and ash according to the methods of A.O.A.C. (1977). The gross energy content (GE) was determined by bomb calorimetry. In Trial II, samples of feed and faeces were analysed as described for Trial I. Urine N was determined in 5-ml samples. Energy, in 50-ml freeze-dried urine samples, was determined with a Gallenkamp adiabatic calorimeter (CB-100).
Statistical methods For the growth trial (Trial I), the results were treated by analysis of variance using the general linear model (GLM) procedure in the Statistical Analysis System (SAS) described by the SAS Institute (1982). Average values for production results and carcass characteristics are given as least squares means and Duncan's multiple range test was used to find significant differences (P < 0.05) between the variables. In Trial II, statistical analyses were performed using the analysis of variance (ANOVA) procedure in the Statistical Analysis System (SAS) described by the SAS Institute Inc. (1982). The following model was used: Y = ABCA*B where Y -- the dependent variable; A, B and C the effects of diet, period and animal, respectively; A*B = interactions between diet and period. RESULTS
Trial I The results from Trial I are given in Table 2. Treatment 4 resulted in significantly greater rates of live-weight gain than Treatment 3. It also took ~ 5 days longer for the pigs on Treatment 3 to reach slaughter weight than for pigs on Treatment 4. No significant differences were found between the treatments in feed conversion or carcass quality.
125 TABLE 2 The effect of treatment on performance, feed conversion and carcass quality Treatment
Live-weight gain (91 day) (g) No. of days to slaughter weight Feed conversion (kg feed/kg gain) Meat in carcass (%)
1
2
3
4
749 ab 108~b 3.4 57.8
715 ab 107ab 3.3 58.6
735 b 109a 3.4 57.8
771 a 104b 3.2 57.3
Means in the same row with common superscripts do not differ significantly (P < 0.05).
Trial H
Since no interactions were found between diet and period, these effects were discarded from the model. A summary of ANOVA for each dependent variable for the four diets is given in Table 3. According to the F-test, the model as a whole (adjusted for the mean) accounted well for the behaviour of the dependent variable, except for the efficiency of N retention, net protein utilization (NPU) and biological value (BV). Additionally, R 2 is high, showing that the
TABLE 3 Summary of the analysis of variance for the digestibility and nitrogen balance trial Dependent variable Diet digestibility coefficient Organic matter Crude protein Energy Nitrogen balance (g day -1) Urinary N N retained Efficiency of N retention Of ingested N Of digested N Biological value Net protein utilization DE content (MJ k g - i D M ) ME content (MJ kg- 1DM) aCV = coefficient of variation (%)
Mean 0.842 0.796 0.815
CVa
R2
F-value
1.3 2.2 1.5
0.684 0.833 0.779
3.0** 6.9*** 4.9***
9.4 11.5
0.910 0.809
14.1"** 5.9***
0.387 0.486
10.7 9.8
0.453 0.483
1.2N s 1.3 Ns
0.571 0.465 14.7 14.1
8.1 9.0 1.5 1.5
0.456 0.435 0.835 0.832
1.2Ns 1.1Ns 7.0*** 6.9***
16.7 15.7
126 TABLE 4 The effect of treatment on the apparent digestibility of nutrients, DE and ME contents of the diets Treatment 1 Digestibility coefficient Organic matter Crude protein Energy DE content (MJ k g - l D M ) ME content (MJ k g - l D M )
0.842 0.7945 0.8115 14.75 14.15
2
3 0.838 0.7855 0.8095
14.4 ° 13.85
4 0.841 0.7885 0.8145
14.5be 13.95
F-value 0.849 0.817 a 0.827 ~
1.4Ns 5.6** 3.4*
15.0 a 14.4a
12.6"** 12.5"**
Means in the same row with common superscripts do not differ significantly (P < 0.05) TABLE 5 The effect of period on the apparent digestibility coefficients of nutrients and energy, and DE and ME contents of the diets Period
Digestibility coefficients Organic matter Crude protein Energy DE content (MJ kg1 DM ME content (MJ kg -1 DM)
I
II
III
IV
F-value
0.8305 0.764 c 0.7965 14.35 13.75
0.840 a5 0.7905 0.814 a 14.6 ~ 14.1 ~
0.849 a 0.813 a 0.824 ~ 14.8a 14.2~
0.851 a 0.817 a 0.826 a 14.9 ~ 14.2 a
6.0** 15.0"** 9.7*** 9.,6"** 9.7***
Means in the same row with common superscripts do not differ significantly (P < 0.05). model fits well to the data. The variation (CV) in the population especially for variables not connected to the protein utilization.
is s m a l l ,
The effects of diets Apparent digestibility coefficients of nutrients and energy, and the digestible energy (DE) and metabolizable energy (ME) contents of the diets are g i v e n i n T a b l e 4. T h e t r e a t m e n t s h a d s i g n i f i c a n t e f f e c t s o n t h e d e p e n d e n t v a r i ables (P < 0.05), except for the digestibility of organic matter. The digestibility coefficients for protein and energy for Treatment 4 (rolled before pelleted), and the DE and ME contents of the diet were significantly higher than
127
in other treatments. No significant differences were found between the diets in nitrogen balance, efficiency of N retention, BV and NPU.
The effects of animals and periods The effect of animal on the dependent variables was seldom significant and only in a few cases was there a difference between animals. On the other hand, the effect of period was highly significant and considerable differences were found between periods, especially between the first period and the others, for the digestibility coefficients of nutrients and for DE and ME contents of the diets (Table 5). DISCUSSION
The results from the feeding trial show that whole-grain pelleting to a greater pellet size than ~ 3.0 m m reduced the live-weight gain of the pigs. These results are in good agreement with those of Ogle and Lund (1985). The best growth response was obtained when the diet was subjected to two processes, i.e., rolling before pelleting (Treatment 4). This processing method resulted in significantly higher daily live-weight gain of the pigs than wholegrain pelleting to 3.9 m m pellets. On the other hand, the differences in daily live-weight gain between T r e a t m e n t 4 and Treatments 1 and 2 were not significant. Choosing between these treatments is, therefore more an economic question than a question of better response. The results from the digestibility study confirm the results from the feeding experiment. The most efficient utilization was obtained for the diet which was subjected to the two processes (Treatment 4). Both the digestibility of CP and energy, and the ME content of the diet, were significantly higher for this treatm e n t than for other treatments. The digestibility coefficients of nutrients and energy, and the ME content of the diets, were significantly lower in the first period than in the others. The pigs only weighed between 24.0 and 29.1 kg in the first period, and it is assumed that the digestive systems of the animals were not fully developed at that time. Similar effects of period on digestibility have been reported by several workers (Christison and Parra de Solano, 1982; Fernandez et. al., 1986; H15dversson, 1987). REFERENCES Andersson, K., 1985. SLU-normen - en ny utfodringsnorm f6r slaktsvin. (The SLU-standard - a new feeding standard for pigs. ) Swedish University of Agricultural Sciences, Research Information Centre, Report No. 67, pp. 6-13. Association of Official Analytical Chemists, 1977. Official Methods of Analysis. A.O.A.C., Washington, DC.
128 Christison, G.I. and Parra de Solano, N.M., 1982. Utilization of protein from peas, barley, buttermilk powder and soyabean meal by early weaned pigs. Can. J. Anim. Sci., 62: 899-905. Fernandez, J.A., JSrgensen, H. and Just, A., 1986, Comparative digestibility experiments with growing pigs and adult sows. Anim. Prod., 43: 127-132. GSransson, L. and Ogle, R.B., 1985. Anaerobically stored high moisture cereals for growing pigs. Anim. Feed Sci. Technol., 12: 159-169. H15dversson, R., 1987. The nutritive value of white- and dark-flowered cultivars of pea for growing-finishing pigs. Anim. Feed Sci. Technol., 17: 245-252. Ogle, R.B. and Lund, S., 1985. Helk~irnspelletter av gast~itt lagrad spannm~l och ~ t e r som foder till slaktsvin. (Whole grain pelleted cereals and peas as a feed for growing-finishing pigs.) Swedish University of Agricultural Sciences, Research Information Centre, Report No. 67, pp. 1-5. SAS Institute Inc., 1982. SAS User's Guide: Statistics, SAS Institute Cary, NC, 584 pp. Simonsson, A. and G6ransson, L., 1982. Otorkad spannm~l som svinfoder. (Undried cereals as a pig feed.) Aktuellt fr~n lantbruksuniversitetet 310, Uppsala.