1. Effect on Nutrient Digestibility and
Nitrogen Balance in Grower Pigs fed
Three Forms of Blended Cassava Roots
Michael Dom, Workneh Ayalew, Phil Glatz, Roy Kirkwood & Paul Hughes

2. Outline of seminar
• Introduction - feeding value of cassava to
grower pigs
• Metabolic Experiment
• Results & Discussion
• Key findings & Conclusion
• Implications & Recommendations for R,D&E
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3. INTRODUCTION
Metabolic trial on the feeding value of cassava roots to grower pigs
Experiment conducted at Labu Livestock Station
Wau-Bulolo Road, Lae Morobe Province
PNG National Agriculture Research Institute
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4. Cassava as animal feed(1)
• Roots are readily available & common pig feed
• Low dry matter content 18-40%
– >80% starch, low fibre, <3% protein, imbalance of essential
amino acids (EAA) particularly methionine (Ravindran, 1993)
– Used as a dry or wet feed, leaves for protein but are less
palatable and used in smaller proportions
– Also contain several anti-nutritional factors and dietary
fibre, require some processing to prepare feed
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5. Cassava as animal feed(2)
• Processing to remove anti-nutrients
– Grating and milling is most effective root
processing (Teka et al, 2013)
– Drying at <100°C may not be effective for
reducing HCN and protease inhibitors (Teka et al, 2013; Cardoso et al,
2005; Marfo et al, 1990)
– Fermenting and boiling significantly reduces HCN,
phytates, tannins and oxalates (Teka et al, 2013; Cardoso et al, 2005; Marfo et al,
1990)
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6. Metabolic experiment on grower pigs
• Feeding cassava as boiled, ensiled & milled roots
Objective:
Evaluation of feeding value of three nutritionally
balanced, blended diet formulations in commercial
crossbred grower pigs (Large White-Landrace x Duroc)
compared to a standard grower feed
Hypothesis:
There are no significant differences between diets for
digestibility of nutrients and energy and performance in
grower pigs
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7. Experiment feeding value cassava
roots to grower pigs
Experimental procedures:
• Used a Latin Square Design as 4 Treatments x 4 Replicates and with
x 4 Feeding periods this affords n = 64 experimental units
• Four castrate male pigs at 25kg (8 weeks old)
• Fed ad libitum for 24 hours
• Clean fresh piped water available at all times
• 5 days adaptation, 3 days collection by four periods (32 days)
• Sampling at 24 hour intervals on three days and were pooled for
chemical testing
• Chemical analysis of feed, faeces & urine
• Proximate nutrients & nitrogen balance
• Urine samples were stored at <10°C after collection
• Faeces were oven dried at 105°C and stored in sealed bags in a dry
shed
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8. Large White-Landrace x
Duroc crossbred pigs
Milled cassava
Grated cassavaPeeled & chopped cassava
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9. Experimental set-up
• Fed 2000g DM, blended as fresh
weight and topped-up twice daily
• Water available from nipple drinkers
• Temperature monitored and cages
aerated by floor fans
• Faeces trapped on sliding trays
beneath each cage then collected
into buckets
• Urine drained and filtered into
sealed, dark glass bottles for
measuring volume and sampling
Blended diets
Metabolic cage (back)Metabolic cage (front)
Pigs released
from cages
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10. Table 1: Feed components, processing and particulars for making each
Treatment-diet
Feed Components Processing Particulars Label
Pig
concentrate1
Meal
Mixed in factory -
meal
See Table B; blended at 45%
DM of 2000g daily ration
45
Standard pig
grower
~10 mm
Pellets
Pellets, rolled to <
5mm size
Manufactured feed, 16% crude
protein, 14MJ/kg ME
STDPG
Cassava Roots Milled and dried
Grated then sun/oven dried
105°C to ~80% moisture loss
CAMR45
Cassava Roots Ensiled wet
Grated then ensiled by
standard methods (+0.5% w/w
Na)
CAER45
Cassava Roots
Five days curing,
2-3 weeks
storage, boiled
Chopped, placed in boiling
water for 45-60 minutes (+0.5%
w/w Na), drained
CABR45
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11. Nutrients (%)
Components Treatments
CABR CAER CAMR PigConc1 CABR45 CAER45 CAMR45 STDPG
Dry Matter 38.8 35.4 88.8 87.9 51.5 48.1 88.4 88.0
Ash 1.00 0.92 2.30 8.80 4.58 4.53 5.28 6.39
Fiber 0.61 0.56 1.40 4.10 2.21 2.19 2.64 5.64
Ether Extract
(fats)
0.26 0.24 0.60 4.40 2.16 2.14 2.34 3.78
Crude Protein 0.74 0.68 1.70 32.9 15.4 15.4 15.9 16.5
NFE† 36.2 33.0 82.8 37.7 37.4 35.7 63.2 55.7
Total N 0.12 0.11 0.27 5.26 2.47 2.47 2.55 2.64
Lysine* - - - 2.03 0.89 0.90 0.89 0.86
Methionine* - - - 0.82 0.36 0.36 0.36 0.24
Meth+Cyst* - - - 1.26 0.56 0.56 0.55 0.53
DE (MJ/kg)** 16.8 16.9 16.1 15.6 16.3 16.3 15.9 14.8
Lys:DE (g/MJ)*** - - - - 0.57 0.57 0.58 0.60
Table 2: Nutrient composition of the feed components and
experimental treatments
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12. RESULTS & DISCUSSION
Metabolic trial on the feeding value of cassava roots to grower pigs
Experiment conducted at Labu Livestock Station
Wau-Bulolo Road, Lae Morobe Province
PNG National Agriculture Research Institute
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13. Digestibility
(%)
Grand
mean
Treatment means
sed lsd F pr. cv%
CABR45 CAER45 CAMR45 STDPG
Dry matter 78.7 81.0a 82.5a 82.4a 68.7b 2.12 5.18 0.002 3.8
Ash 40.6 36.0 44.5 50.1 31.9 7.03 17.20 0.137 24.5
Fats 58.9 57.9 56.2 67.2 54.2 4.80 11.75 0.127 11.8
Fiber 28.0 21.7a 20.8a 31.0a,b 38.5b 5.24 13.46 0.055 26.5
Protein 75.7 73.1 75.8 75.9 78.0 2.13 5.22 0.258 4.0
NFE† 82.1 82.9a 82.4a 89.9b 73.2c 2.76 6.74 0.006 4.7
Energy 87.0 88.7a 89.0a 89.1a 81.1b 1.31 3.21 0.002 2.1
Table 3: Apparent total tract digestibility in grower pigs fed blended
cassava root diets
Means with different superscripts are significantly different at p<0.05.
† NFE is Nitrogen free extracts, a calculated estimate of carbohydrate content.
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14. N balance
(g/d)
Grand
mean
Treatment means
sed lsd F pr. cv%
CABR45 CAER45 CAMR45 STDPG
Intake 54.4 59.2 47.3 52.4 58.6 4.60 11.25 0.116 12.0
Feces 13.0 15.3 11.4 12.4 13.0 1.32 3.24 0.108 14.4
Digested 41.3 43.9 35.9 39.9 45.6 3.93 9.61 0.162 13.4
Urine 17.3 18.0 15.8 16.1 19.5 4.67 11.43 0.839 38.1
Retained 27.0 29.9 25.9 24.6 27.6 1.88 4.60 0.119 9.8
Retention as % of:
N-intake 48.9 50.0 56.0 44.3 45.1 4.89 11.96 0.163 14.1
N-digested 64.7 68.3 74.7 58.4 57.4 6.85 16.75 0.121 15.0
Table 4: Nitrogen balance in grower pigs fed blended cassava root
diets
Means with different superscripts are significantly different at p<0.05.
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15. Table 5: Performance of Crossbred Grower Pigs fed Cassava Blended
with Protein Concentrate (Treatments)
Treatment means
Parameter
Grand
mean
CABR45 CAER45 CAMR45 STDPG sed lsd F pr. cv%
DMI
(g/day)
2080 2382a 1776b 2083c 2080c 73.8 180.6 0.001 5.0
ADG
(g/day)
890 865a 800a 1072b 823a 51.4 125.9 0.006 8.2
FCR
(kg/kg)
2.54 3.06a 2.37b 2.12b 2.59b 0.157 0.384 0.005 8.7
Values with different superscripts are significantly different at P < 0.05.
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16. Fig. 1: Lysine:DE ratios vs ADG and FCR for commercially bred growing pigs fed
for cassava blended diet compared to the standard Pig Grower ration
(Control) and reference values (Dom et al., 2014) 16

17. Key findings
• Apparent Total Tract Digestibility of nutrients was similar
between three cassava blends and improved against the
standard feed, while N-retained was similar (156.25 to 187.5
g/day CP)
• Agreement with literature values (e.g. Ospina et al., 1995;
Phuc et al., 2000; An et al., 2004)
• It is surmised that processing effectively reduced anti-
nutritional factors (Dietary fibre, TI’s, phytates, tannins,
oxalates )
• Feed intake, efficiency and growth performance of cassava
blended diets was equal or better than standard pig grower
feed
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18. Conclusions
• Cassava roots blended at 55% of the diet improved the
nutrient and energy utilization to grower pigs regardless of
the mode of preparation
• Test diets demonstrated their suitability to high performing
genotypes compared against a wheat based standard feed
• This feed should be tested on the local mixed genotype pigs
farmed in PNG
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19. Implications & Recommendations
• Pig Grower uses 91.2% wheat
while Pig Conc.1 uses 47.8%,
which is 43.4% less wheat
• Blended at 45% DM in the
cassava root diets this means
that wheat use was effectively
reduced to only 21.5% wheat
• Compared to the Pig Grower
this means a total reduction
of wheat use by 69.6% in the
improved cassava ration
• Boiled cassava – for village
extensive farming, informal,
customary market (Several
farmers to test feed)
• Ensiled cassava – for small-
scale intensive piggeries, that
serve dual customary/fresh
meat markets (Test at 3 farm
locations)
• Milled cassava – for intensive
commercial piggeries serving
formal markets (Integrate with
feed mills activities)
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20. ACKNOWLEDGEMENTS
Charlie, Arthur, Elly, Labu Pig section, Margaret & Collin Cargill
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