The following article is a special collaboration from AFMA (Animal Feed Manufacturers
We thank their kind support.
Pig producers continuously strive to save on feed cost as feed cost constitute
70 – 80% of production cost and even a small saving per tonnage can translate
into a large saving per annum. If this saving does not interfere with growth
performance it could end up as profit in the pocket of the producer.
Weaning a piglet at 21 or 28 days causes a lot of stress due to dietary, environmental
and social changes. This usually results in a post weaning lag phase seen in
slow growth, scouring and general unthriftiness (Ravindran & Kornegay, 1993).
The piglets immunity is at it’s lowest at around 21 days while the digestive
system is not fully developed and it can therefore not fully utilise the feedstuffs
generally fed to older animals. This scouring and unthriftiness could also be
acounted for by the changes found in the morphology of the small intestine shortly
after weaning (Miller et al. ,1986; Van Beers-Schreurs et al., 1998). These
changes include reduction of villus height, increased depth of lamina propria,
reduced disaccharidase concentrations and reduced absorption (Dunsford et al.,
1989). This decrease in villus height can be caused by pathogens (Vellenga et
al., 1992), antigens (Miller et al., 1986; Li et al., 1991) or reduced feed
intake (Nunez et al., 1996; Pluske et al., 1996; Van Beers-Schreurs et al.,
1998). Due to weaning stress and the immature immune system newly weaned pigtlets
are more susceptible to infections caused by pathogens, any infections or palatability
problems could also lead to decreased feed intake which will further influence
gut histology. If, on top of all this, the feed supplied to the animal contains
antigens the stress could be such that production losses during this period
might not be compensated for during the grower period. This could lead to direct
or indirect financial losses to the producer.
The feeding of weaners has therefore been responsible for a lot of debate and
controversy in the pig industry. Some producers opt for optimisation of growth
while others do for maximisation of growth rate by feeding high levels of milk
protein and pre cooked starches. Seve (1985) stated that the early weaning process
creates an initial physiological situation requiring a particular nutrient form
and balance in the feed. It has thereforee become common practice to use milk
products and pre-cooked starches in creep diets (Campbell & Dunkin, 1983;
Aherne & Nielsen , 1982; Campbell & Taverner, 1986 and Campbell et al.,
1988). Furthermore it has been well documented that growth rate and the efficiency
of feed utilisation of early-weaned piglets is appreciably better when milk
proteins is used instead of soyabean proteins (e.g. Wilson & Leibholz, 1981;
Walker et al., 1986; Zijlstra et al., 1996). Milk products are, however, very
expensive and can cost in the order of R 16 000 per ton. The inclusion of these
products can therefore lead to complete weaner diet costing up to R 4000 per
ton. If a good quality, highly digestible, cheaper protein source could substitute
all or part of this milk protein, it could lead to a saving of up to R 400 per
ton or more. One such product which shows potential is 48% soyabean oilcake
meal, also known as high protein soya bean oilcake meal. Many pig producers
are, however, still reluctant to include it in their weaner diets because of
problems experienced with quality control during processing and the subsequent
danger of the presence of anti-nutritional factors which could lead to additional
stress and digestive upsets in the newly weaned piglet.
Soyabeans and byproducts from soyabean processing are recognised as an excellent
protein source in pig feeds (Danielson & Crenshaw, 1991). Soyabean oilcake
meal contains all of the indispensable amino acids, although the concentrations
of cystine and methionine are sub-optimal (Danielson & Crenshaw, 1991) and
the digestibility of the first limiting amino acid, lysine, is low (Sohn et
Reduced performance in pigs fed soyabean protein has been associated with reduced
digestibility of the amino acids (AA) in the diets fed (Wilson & Leibholz,
1981; Leibholz, 1986 and Viljoen & Ras, 1989). Digestibility is influenced
by a number of aspects. These include the presence of anti-nutritional factors
(Sauer & Ozimek, 1986; Huisman & Jansman, 1991), inclusion levels (Viljoen
et al., 1998), post weaning feed intake (Makkink et al., 1994), the presence
of antigens (Li et al. 1991) as well as AA damage due to processing (Marty &
Chavez, 1995). Anti-nutritional factors such as trypsin inhibitor will bind
to the enzyme trypsin which will render this enzyme inactive and therefore not
available for hydrolysis of the protein. Decreased feed intake after weaning
will affect pancreatic development and thus enzyme activity (Makkink et al.,
1994) while the presence of antigens can cause certain immunological responses
in early weaned pigs resulting in, amongst others, decreased villus height and
thus digestibility. Another factor which influences digestibility is overheating
during processing which leads to the binding of protein to certain sugars rendering
it indigestible (Marty & Chavez, 1995). Many of the above mentioned aspects
are intrinsic characteristics of soyabean oilcake meal and must be taken into
consideration when diets are formulated.
Problems as stated above can be overcome if diets are formulated on digestible
amino acid content. Results of Viljoen (1998) showed that weaner diets based
on different protein sources can be utilised with equal efficiency (feed conversion)
when balanced on digestible amino acid contents and not on total amino acid
contents and the palatability of the diets are such that it does not influence
intake. It’s good palatability and the composition of high protein soyabean
oilcake meal together with modern technology with regard to feed formulation
and recent information on amino acid digestibility values could possibly rectify
part or all of these limitations.
A study was therefore conducted at the Agricultural Research Council’s
Animal Nutrition and Animal Products Institute. The objectives of the trial
were two fold. Firstly to test to what extent either milk powder, fishmeal or
both as the main protein source in weaner diets, could be substituted by high
protein soyabean oilcake meal (48% crude protein) and secondly to measure the
effect of the different diets on the histology of the small intestine.
For trial purposes eighty piglets, 40 boars and 40 gilts, of a commercial crossbred
strain were used. The piglets were weaned at 28 days and randomly allocated
to four different dietary treatments, this design rendered 20 piglets, 10 per
sex type, per treatment. Piglets were kept in pairs (a boar and a gilt together),
in flat deck type pens (1.5 x 1.0m) with perforated metal floors and equipped
with self feeders and automatic water nipples. The piglets had ad libitum access
to their allotted diets and clean water.
Treatment diets were formulated to contain either milk powder and fishmeal,
milk powder and high protein soyabean oilcake meal, fishmeal and high protein
soyabean oilcake meal or high protein soyabean oilcake meal alone as main protein
source(s). Treatments diets were further formulated on digestible amino acid
basis using the ideal amino acid pattern as described by Kemm et al. (1990)
for all amino acids except tryptophan where the value as listed by Wang &
Fuller (1989) was used. Digestibility values as described by Rhône-Poulenc
(1993) were used for all amino acids except tryptophan where the table of Degussa
(1993) was used. Treatment diets and their composition are shown in Table 1.
Table 1 Ingredient and digestible nutrient
composition of experimental diets.
|Ingredient composition (as is)
|High protein soyabean oilcake meal
|Skimmed milk powder
|Digestible nutrient composition
|Total sulphur containing aminoacids
| DE (pig)
*MP – Milk powder
**FM – Fish meal
***HPS – High protein soyabean oilcake meal
The trial continued for four weeks during which time measurements were taken
on a weekly basis. These measurements were animal weight, weight of feed supplied
during the week and weight of feed residues at the end of the week. These values
were used for the estimation of average daily gain and feed conversion ratios.
At the end of the four week period five piglets per treatment were selected
from the middle weight block and slaughtered. The small intestine was removed
and placed in saline solution, the mesenteric web was cut and the intestine
laid out straight. Samples were then taken at the terminal duodenum, mid-jejunum
and distal jejunum according to the method described by (Dunsford et al., 1989;
Healy et al. ,1994). Villus height and lamina propria depth was determined by
means of interactive image analysis as described by Dunsford et al. (1989).
Ten villus heights and ten lamina propria depth measurements were made from
each of three cross sections per sample. These measurements were averaged to
result in one observation.
Statistical analyses were done by the Agricultural Research Council’s biometry
group using Genstat 5 release 3.2 (Genstat 5, 1993). All requirements concerning
homogeneity and normality were met.
The results obtained from this trial are shown in Table 2 and 3 below. Average
daily gain was estimated by fitting a linear model (R2>0.92) to live weight
data. The slope of this curve represents the ADG which was used for further
data analysis. Average daily gain (ADG) did not differ significantly between
sexes (boars - 376 g/d; gilts - 354 g/d) or treatments. These results are in
contrast with those reported by Li et al. (1991) who found that pigs fed diets
containing soyabean meal had a lower (P < 0.05) rate of gain than the control
group. The differences between the current trial and the report of Li et al.
(1991) could possibly be attributed to the diets of the current trial being
formulated on a digestible amino acid basis. Presumably, that had not been the
case in the study of Li et al. (1991).
Total intake as measured per pen and feed conversion ratios did not differ
significantly (P<0.05) between treatments. This could be of significance
as gut morphology, especially villus heights, is negatively influenced by reduced
feed intake (Nunez et al., 1996; Pluske et al., 1996; Van Beers-Schreurs et
al., 1998). As intake did not differ between treatments it can be assumed that
intake did not influence villus height in this trial and that any differences
observed could be attributed to the ingredient composition of the diets.
Table 2 Average daily gain (ADG), feed
conversion ratio (FCR) and total intake from 4 to 8 weeks of age for different
|| ADG (g / day)
||FCR (kg feed / kg gain)
|MP* + FM**
||353 + 102
||1.56 + 0.05
||30.63 + 4.10
|MP + HPS***
||349 + 106
||1.61 + 0.09
||31.48 + 7.44
|HPS + FM
||1.58 + 0.13
||32.08 + 6.61
||383 + 77
||1.49 + 0.08
||32.07 + 4.54
*MP – Milk powder
**FM – Fish meal
***HPS – High protein soyabean oilcake meal
Treatment had no significant (P<0.05) influence on gut histology Table 3,
the only differences noted were differences between sites of sampling and specifically
between samples taken from the terminal duodenum and the other areas of sampling.
These differences were, however, anticipated as the histology of different parts
of the small intestine is different. These results are in contrast to what was
found by Dunsford et al. (1989) and Li et al. (1991) who found that feeding
high concentrations of soyabean meal post weaning decreased villus height. This
could be attributed to a number of factors which are not known but could include
the age of the piglets at sampling, the use of digestibility values for diet
formulation in the trial being reported on or differences in anti nutritional
factor content of the soyabean oilcake meals.
Table 3 Villus heights (mm) measured
at different anatomical sites in the small intestine
|MP* + FM**
||1.846 + 0.37
||1.670 + 0.20
||1.516 + 0.19
|MP + HPS***
||1.804 + 0.28
||1.498 + 0.35
||1.416 + 0.16
|HPS + FM
||1.744 + 0.27
||1.608 + 0.35
||1.472 + 0.29
||1.598 + 0.19
||1.432 + 0.14
||1.376 + 0.20
*MP – Milk powder
**FM – Fish meal
***HPS – High protein soyabean oilcake meal
From the results of the current study it can be concluded that high protein
soyabean oilcake meal can be utilised successfully in diets of weaner pigs,
alone or in combination with other protein sources without affecting production
parameters or gut histology. This conclusion holds as long as diets are formulated
on digestible amino acid basis, the soyabean oilcake meal is processed correctly
and the quality known.
Appreciation is expressed to ARC – ANPI and NOPO for the funding of the
Aherne, F.X. & Nielsen, H.E., 1982. Lysine requirement of pigs weighing
7 to 19 kg live weight. Can. J. Anim. Sci. 63, 221-224.
Campbell, R.G. & Dunkin, A.C., 1983. The influence of dietary protein
and energy intake on the performance, body composition and energy utilisation
of pigs growing from 7 to 19 kg. Anim. Prod. 36, 185-192.
Campbell, R.G. & Taverner, M.R., 1986. A note on the response of pigs
weaned at 28 days to dietary protein. Anim. Prod. 42, 427-442.
Campbell, R.G., Taverner, M.R. & Rayner, C.J., 1988. The tissue and dietary
protein and amino acid requirements of pigs from 8 to 20kg live weight. Anim.
Prod. 46, 283-290.
Danielson, D.M. & Crenshaw, J.D., 1991. Raw and processed soybeans in
swine diets. In: Swine Nutrition. Ed. E.R. Miller, D.E. Ullrey, A.J. Lewis.
Butterworth-Heinemann, Stoneham, USA.
Degussa (1995), Amino acid recommendations for swine.
Dunsford, B.R., Knabe, D.A. & Haensly, W.E., 1989. Effect of dietary
soyabean oilcake meal on the microscopic anatomy of the small intestine in
the early-weaned pig. J. Anim. Sci. 67, 1855-1863.
Genstat 5, 1993. Genstat 5 committee of the statistical department IACF –
Rothamsted U.K., 1995. GENSTAT 5 Reference Manual Clarendon press: Oxford.
Healy, B.J., Hancock, J.D., Kenney, G.A., Bramel-Cox, P.J., Behnke, K.C.
& Hines, R.H., 1994. Optimum particle size of corn and hard and soft sorghum
for nursery pigs. J. Anim. Sci. 72, 2227-2236.
Huisman, J. & Jansman, A.J.M., 1991. Dietary effects and some analytical
aspects of anti nutritional factors in peas (Pisum sativum), common beans
(Phaseolus vulgaris) and soyabeans (Glycine max L.) in monogastric farm animals.
A literature review. Nutr. Abstr. Rev. 61, 901-921.
Kemm, E.H., Siebrits, F.K. & Barnes, Penelope M., 1990. A note on the
effect of dietary protein concentration, sex, type and live weight on whole-body
amino acid composition of the growing pig. Anim. Prod; 51: 631-634.
Leibholz, J., 1986. The utilisation of lysine by young pigs from nine protein
concentrates compared with free lysine in young pigs fed ad lib. Brit. J.
Nutr. 55, 179-186.
Li, D.F., Nelssen, J.L., Reddy, P.G., Blecha, F., Klemm, R.D., Gieting, D.W.,
Hancock, J.D., Allee, G.L. & Goodband, R.D., 1991. Measuring suitability
of soyabean products for early weaned pigs with immunological criteria. J.
Anim. Sci. 69(8); 3299-3307.
Makkink, C.A., Negulescu, G.P., Guixin, Q. & Verstegen, M.W.A., 1994.
Effect of dietary protein source on feed intake, growth, pancreatic enzyme
activities and jejenal morphology in newly-weaned piglets. Brit. J. Nutr.
Marty, B.J. & Chavez, E.R., 1995. Ileal digestibilities and urinary losses
of amino acids in pigs fed heat processed soyabean products. Livest. Prod.
Sci. 43, 37-48.
Miller, B.G., James, P.S., Smith, M.W. & Bourne, F.J., 1986. Effect of
weaning on the capacity of pig intestinal villus to digest and absorb nutrients.
J. Agric. Sci. 107;579.
Nunez, M.C., Bueno, J.D., Ayudarte, M.V., Almendros, A., Rios, A., Suarez,
M.D. & Gil, A., 1996. Dietary restriction induces biochemical and morphometric
changes in the small intestine of nursing piglets. J. Nutr. 126(4); 933-944.
Pluske, J.R., Williams, I.H. & Aherne, F.X., 1996. Maintenance of villus
height and crypt depth in piglets by providing continuous nutrition after
weaning. Anim. Sci. 62(1); 131-144.
Ravindran, V. & Kornegay, E.T., 1993. Acidification of weaner Pig Diets:
A Rev.. J. Sci. Fd. Agric. 62, 313-322.
Rhone Poulenc, 1993. Rhodiment Nutrition Guide. Rhone Poulenc animal nutrition.
Sauer, W.C. & Ozimek, L., 1986. Digestibility of amino acids in swine:
Results and their practical applications. A Review. Livest. Prod. Sci. 15,
Seve, B., 1985. Physiological basis of nutrient supply to piglets. World
Rev. Anim Prod. XXI, (2), 8-14.
Sohn, K.S., Maxwell, C.V., Southern, L.L. & Buchanan, D.S., 1994. Improved
soybean protein sources for early-weaned pigs: 2. Effects on the ileal amino
acid digestibility. J Anim. Sci. 72 (3); 631-637.
Van Beers-Schreurs, H.M.G. , Nabuurs, M.J.A.; Vellenga, L., Kalsbeek Van
Der Valk, H.J., Wensing, T. & Breukink, H.J., 1998. Weaning and the weanling
diet influence the villus height and crypt depth in the small intestine of
pigs and alter the concentrations of short-chain fatty acids in the large
intestine and blood. J. Nutr. 128(6); 947-953.
Vellenga, L., Egberts, H.J.A., Wensing, T., Van Dijk, J.E., Mouwen, J.M.V.M.
& Breukink, H.J., 1992. Intestinal permeability in pigs during rotavirus
infection. Am. J. Vet. Res. 53(7); 1180-1183.
Viljoen, J. & Ras, M.N., 1989. A note on different ratios of lysine to
digestible energy in diets of piglets weaned at three weeks of age. S. Afr.
J. Anim. Sci. 19, 133-136.
Viljoen, J. 1998. Amino acid digestibility of feedstuffs for pigs. Ph.D.
Thesis, University of Stellenbosch.
Viljoen, J., Ras, M.N., Hayes, J.P. & Siebrits, F.K., 1998. Apparent
and true amino acid digestibilities of feedstuffs in pigs employing the total
ileal content (tic) technique and the mobile nylon bag (mnbt) technique. Livest.
Prod. Sci. 53; 205-215.
Walker, W.R., Morgan, G.L. & Maxwell, C.V., 1986. Ileal cannulation in
baby pigs with a simple T-cannula. J. Anim. Sci. 62; 407-411.
Wang, T.C. & Fuller, M.F., 1989. The optimum dietary amino acid pattern
for growing pigs. 1. Experiments by amino acid deletion. British journal of
Nutrition. 62(1): 77-89. Förderungsdienst. 42(5); 140-144.
Wilson, R.H. & Leibholz, J., 1981. Digestion in pigs between 7 and 35d
of age. III. The digestion of nitrogen in pigs given milk and soya-bean proteins.
Br. J. Nutr. 45; 337-346.
Zhang, Y., Partridge, I.G., Keal, H.D. & Mitchell, K.G., 1985. Dietary
amino acid balance and requirements for pigs weaned at three weeks of age.
Anim. Prod. 38; 441-448.
Zijlstra, R.T., Whang, K.Y., Easter, R.A. & Odle, J., 1996. Effect of
feeding milk replacer to early weaned pigs on growth, body composition, and
small intestinal morphology, compared with suckled littermates. J. Anim. Sci.
C:DATAMatrixSEPTEMBER 2000Protein sources for piglets-elsje p.doc