| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
ANIMAL GROWTH, PHYSIOLOGY, AND REPRODUCTION |
,2,3
ski
* Department of Cell and Organism Biology, Lund University, S-22362 Lund, Sweden;
and
Animal Nutrition Group, Wageningen University, 6700 AH Wageningen, the Netherlands;
and
Department of Agricultural Biosystems and Technology, Swedish University of Agricultural Science, S-23053 Alnarp, Sweden; and
and
The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 05-110 Jablonna, Poland
 |
Abstract |
|---|
 Top Abstract INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
18 pmol·L–1) and showed low correlations with the pancreatic secretion traits. Plasma immunoreactive cationic trypsin was not significantly related to any of the pancreatic secretion traits and should therefore not be used as an indicator for exocrine pancreatic function in milk-fed pigs. Exocrine pancreatic secretion varied substantially among individual pigs (protein, 0.22 to 13.98 mg·kg–1·h–1). Pancreatic protein and trypsin secretion showed a positive, nonlinear relationship with performance traits. It was concluded that neither specific sow’s milk ingredients nor the protein source are responsible for a low pancreatic protein secretion in suckling pigs. Exocrine pancreatic secretion was positively correlated with ADG in pigs at an identical milk intake.
Key Words: growth • milk replacer • pancreas • pancreatic secretion • pig • sow’s milk
|
INTRODUCTION |
|---|
|
TopAbstractINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
). After weaning, the basal pancreatic secretion is much higher and increases 3-fold after feed intake (Pierzynowski et al., 1990; Rantzer et al., 1997). The abrupt development of exocrine pancreatic function seems an obvious mechanism to digest more complex feed ingredients. However, this does not explain the low pancreatic secretion when piglets ingest sow’s milk and substantial amounts of solid feed. Secretion only increases when sow’s milk is completely replaced by solid feed (Pierzynowski et al., 1993, 1995). Therefore, we hypothesized that, apart from the introduction of solid feed, the disappearance of sow’s milk (or one of its components) increases pancreatic secretion after weaning. Bioactive peptides in sow’s milk or the clotting ability of milk protein may explain the low secretion before weaning.
Moreover, the importance of the exocrine pancreas for growth is unknown in milk-fed pigs due to technical limitations to measure milk intake and pancreatic secretion simultaneously. Pancreatic protein secretion shows a positive, linear relationship with ADG in weaned pigs (Botermans and Pierzynowski, 1999). In milk-fed pigs, nonpancreatic enzyme systems are much involved in digestion (Makkink and Verstegen, 1990), and milk is highly digestible (Cranwell and Moughan, 1989); thus pancreatic enzymes may not be indispensable for growth.
This study aimed to compare the effects of sow’s milk and milk replacer on pancreatic secretion and plasma cholecystokinin. Second, 2 milk replacer diets were used to evaluate the effects of clotting vs. nonclotting protein sources on exocrine pancreatic secretion. Third, the relationship between exocrine pancreatic secretion and growth performance was examined, and plasma immunoreactive cationic trypsin was evaluated as an indicator for pancreatic secretion in milk-fed pigs.
|
MATERIALS AND METHODS |
|---|
|
TopAbstractINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
Experimental Design
Nine crossbred, suckling pigs [(Swedish Landrace x Yorkshire) x Hampshire)] were obtained from different litters at the age of 20 to 24 d. Pigs were assigned to 1 of 3 trials (trial 1, 2, and 3). Each trial consisted of 3 experimental periods of 7 d each (period I, II, and III). The trials were assigned to 1 of 3 experimental diets in each experimental period according to Table 1. Period was confounded with age (or BW) of the pigs. Individual pigs could not be assigned to treatments because the feeding system allowed only 1 type of diet to be provided to 3 pigs simultaneously. The 3 trials were therefore conducted sequentially.
|
Animals and Management
The pigs were removed from the sow and weaned from natural suckling to a milk replacer diet (diet B). After 4 d, the pigs were surgically modified for long-term studies of the exocrine pancreatic secretion (Pierzynowski et al., 1988; Thaela et al., 1995). The pigs were anesthetized with halothane (ISC Chemicals, Ltd., Avonmouth, UK) in air (1.5 to 2%, vol/vol) and laparotomized. A Silastic catheter (Dow Corning, Midland, MI) was inserted into the pancreatic duct for the collection of pure, inactivated pancreatic juice. A Silastic T-cannula was placed in the duodenum at the orifice of the pancreatic duct and interconnected externally with the pancreatic duct catheter to maintain a reentrant flow of juice into the duodenum. Another Silastic catheter was implanted in the jugular vein for blood sampling. Between blood samplings, the catheter was filled with saline containing heparin (50 IU of heparin/mL; Pharmacia, Stockholm, Sweden). After surgery, the pigs were allowed to recover for 4 d (on diet B) before the experiment began.
Pigs were housed individually in pens (1.25 x 1.40 m) on a solid floor. The pens were equipped with wood shavings and a heating lamp (150 W) for 24 h·d–1. Each trial of 3 pigs was fed sow’s milk or milk replacer by one feeding system that could be accessed by all individual pigs separately at the same time (Pig’oline, Boss Produkter AS, Ulstrup, Denmark). The animals could see and touch each other and could always move freely. They were exposed to 12 h of light (from 0700 to 1900) and 12 h of darkness. The environmental temperature was maintained at 24°C.
Diets and Feeding
Milk or milk replacer was provided 12 times daily in 2-h intervals at room temperature. Sow’s milk was obtained from sows at Odarslöv Research Farm (Swedish University of Agricultural Science, Odarslöv, Sweden) at 4 wk postfarrowing. A single dose of oxytocin (15 IU, Intervet, Boxmeer, the Netherlands) was administered i.v. in the ear vein of the sows to initiate milk ejection. The udder was cleaned, and milk was collected by manual expression. Sow’s milk (CP, 292 g/kg of DM; crude fat, 381 g/kg of DM; GE, 26.4 MJ/kg of DM) was pooled and stored in bottles at –20°C. Diet A (Universal, Trouw Nutrition, Vejen, Denmark; CP, 245 g/kg of DM; crude fat, 225 g/kg of DM; GE, 22.8 MJ/kg of DM) contained bovine skimmed milk protein as only protein source. Diet B (Porcomel, Nukamel, Olen, Belgium; CP, 255 g/kg of DM; crude fat, 215 g/kg of DM; GE, 22.7 MJ/kg of DM) contained soy protein isolate, hydrolyzed wheat protein, and whey proteins. Milk replacer and sow’s milk, respectively, were reconstituted and diluted to a diet of 2.75 MJ·L–1. All diets were provided at 300% of the ME requirements for maintenance, and ME requirements for maintenance were assumed to be 550 kJ·kg of BW–0.75·d–1 (Noblet and Etienne, 1986; Close, 1987). Milk replacer and sow’s milk in the milk feeding system were renewed 4 times daily. Feed refusals were collected and recorded at 15 min after feeding. Pigs were weighed daily at 0800.
Collection and Analysis of Pancreatic Juice
Total pancreatic secretion was collected between 0900 and 1300 in 30-min sampling intervals. Within the collection period, pigs were fed at 1000 and 1200. After a meal (i.e., from 1000 to 1030 and from 1200 to 1230) the pancreatic secretion was collected in two 15-min sampling intervals. The volume of pancreatic juice was recorded, 0.5 mL of juice was stored at –20°C pending analyses, and the remainder was returned to the duodenum via the duodenal T-cannula. The protein concentration of the pancreatic juice was assessed with the Lowry method (Lowry et al., 1951) modified to be performed on 96-well microplates, with BSA (Sigma Chemical Co., St. Louis, MO) as a standard.
Trypsin activities were measured using a micromodification of the original method of Erlanger et al. (1961). One unit (U) was defined as the amount of enzyme that hydrolyzed 1 µmol of BAPNA substrate (N 
-benzoyl-DL-arginine P-nitroanilide; Sigma Chemical Co.) per minute.
Blood Sampling and Analyses
At 10 min before and 10 min after feeding, 4 mL of blood was sampled from the jugular vein catheter. Blood samples were collected into tubes containing 4 mmol EDTA and 1,000 kIU of aprotinin (Trasylol, Bayer, Leverkusen, Germany) and were immediately ice-chilled. After centrifugation at 2,500 x g for 15 min at 4°C, the plasma was separated and stored at –20°C pending analyses.
Plasma cholecystokinin (CCK) concentrations were determined in ethanol-extracted samples by a double antibody CCK RIA kit (Euro Diagnostica, Malmö, Sweden). The kit was originally designed for the detection of human CCK. The cross-reaction with porcine CCK was 80%, and a cross-reaction of 0.5% with gastrin-17 was found. All samples were analyzed in 1 assay, and the intraassay CV was 6% for CCK.
Plasma immunoreactive trypsin (IRCT) concentrations, a potential indicator of exocrine pancreatic function (Sandström et al., 1986), were determined by a 2-step competitive ELISA, as described by Rennard et al. (1980) and modified for trypsin determination by Sandström et al. (1986). The method was based on competition between immobilized porcine trypsin (Novo Biological Labs, Bagsveerd, Denmark) and trypsin in a standard series or in the unknown plasma samples for specific rabbit antibodies to cationic porcine trypsin produced in our laboratory (Ohlsson et al., 1982). Intra-and interassay CV were 7 and 11% for IRCT.
Calculations and Statistics
Data on exocrine pancreatic secretion were extrapolated from the 4-h sampling period to a 24-h secretion under the assumption that there was no circadian variation in exocrine pancreatic secretion during 24 h (Thaela, 1997). Pre- and postprandial periods were defined as the 60-min period before and after a meal, respectively. Data were expressed per kilograms of BW/hour. The ADG (g) was calculated over the 21-d experimental period. The feed conversion ratio (FCR, mL·g–1) was calculated as the ADFI (mL) divided by the ADG (g).
A total of 120 observations, derived from 8 animals, were used to test treatment effects. One pig was excluded, as described below. Data were analyzed by AN-OVA using a mixed model procedure (SAS Inst. Inc., Cary, NC). The model included fixed effects of treatment (diet A, B, or C), trial (1 to 3), and period (1, 2, or 3), and a random effect of pig within trial. A dummy variable was included as a covariable and represented carryover effects between treatments and between the preexperimental period (all pigs on diet B) and the first experimental period. Covariable effects were, however, nonsignificant and are therefore not reported. Repeated measures on diets were considered, and differences among least squares means were separated using the PDIFF test. Differences between sow’s milk and the average of the 2 milk replacers were determined by orthogonal contrasts. Pearson correlation coefficients between pancreatic secretion traits mutually and between pancreatic secretion traits and plasma IRCT and CCK concentrations were calculated, between and within pigs. The relationships between exocrine pancreatic secretion traits and performance traits were described by a linear model (PROC REG) and by a linear-plateau model with a smooth transition, based on Koops and Grossman (1993; PROC NLIN):
 | [1] |
in which Y = performance trait (dependent variable), X = exocrine pancreatic secretion trait (independent variable), a = intercept, b = slope of the linear phase, and c = point of (smooth) transition for the independent variable. The variances explained by the linear-plateau model were compared with the linear model for the corresponding pancreatic secretion trait by using an F-test. Results are presented as means ± SEM. Significance was set at P < 0.05, trends were identified at P < 0.10, and P values > 0.10 were considered nonsignificant.
|
RESULTS |
|---|
|
TopAbstractINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
Exocrine Pancreatic Secretion
There was a strong correlation between the pancreatic protein and trypsin secretion (r = 0.98; P < 0.001), but neither protein (r = 0.15) nor trypsin secretion (r = 0.17) was correlated with the secreted volume (P > 0.10). The pancreatic secretion of protein and trypsin was affected by pig (P < 0.01) and tended (P < 0.10) to increase with period, whereas no effect of pig or period on the volume of pancreatic secretion was observed (P > 0.10; data not shown).
The volume of pancreatic secretion was about 25% less (P < 0.01) when sow’s milk was fed than when a milk replacer diet was fed (Table 2). Secretion of protein and trypsin did not differ between the 3 diets (P > 0.10). None of the treatments led to a postprandial increase of the pancreatic secretion traits, and the change in secretion in response to feed intake did not differ between treatments (P > 0.10). Pancreatic secretion traits did not differ (P > 0.10) between the 2 milk replacer diets, and secretion of protein and trypsin was similar to that for feeding sow’s milk. The volume of pancreatic secretion averaged 0.94 mL·kg–1·h–1, protein secretion averaged 4.28 mg·kg–1·h–1, and trypsin secretion averaged 1.65 U·kg–1·h–1.
|
). Correlations between the plasma CCK concentrations and pancreatic secretion traits were low, and the highest correlation observed was between the postprandial CCK concentration and pancreatic protein secretion (r = 0.52, P < 0.001).
|
), but preprandial IRCT concentrations tended to be less (P < 0.10) for diet B than for diets A and C, respectively. No response of plasma IRCT levels to feed ingestion occurred (P > 0.10). Plasma IRCT concentrations were not correlated to the pancreatic secretion traits (P > 0.10).
Relationship Between Pancreatic Secretion and Performance
The ADG and FCR increased and decreased (P < 0.05), respectively, with increasing exocrine pancreatic protein secretion (Figure 2). The pig with the lowest pancreatic protein secretion (0.2 mg·kg–1·h–1) also had the lowest ADG (130 g), whereas the pig with the highest pancreatic protein secretion (14.0 mg·kg–1·h–1) gained more than twice as much weight daily (275 g). The FCR, in which the slight differences in daily feed intake were taken into account, showed a similar relationship. The relationship between pancreatic protein (or trypsin) secretion and ADG or FCR was better described by a linear-plateau model than by a linear model (Table 3). Briefly, the estimated growth performance increased until a pancreatic protein output of about 6 mg·kg–1·h–1 was reached. The volume of the secreted pancreatic juice did not show any significant relationship with the performance traits.
|
|
|
DISCUSSION |
|---|
|
TopAbstractINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
1,250 kJ·kg–0.75·d–1; Le Dividich, 1981; Noblet and Etienne, 1986). The ADG (232 g), however, was comparable with the ADG of pigs during the suckling period (180 to 240 g; Williams, 1995). It can therefore be expected that nutrient utilization for growth in the current study was considerably lower than in pigs suckling their sow. The impact of catheterization and cannulation, individual housing, and perhaps isolation from the sow could be the reasons for this difference.
Exocrine Pancreatic Secretion
Feeding sow’s milk instead of milk replacer decreased the volume of exocrine pancreatic secretion but not the protein and trypsin output. It was speculated that the nature of the protein source (clotting vs. nonclotting) would affect the kinetics of digestion and absorption (Hara et al., 1992) and interact with exocrine pancreatic secretion (Valette et al., 1993; Pierzynowski et al., 1997). The substitution of skimmed milk protein (diet A) for whey, soy, and wheat protein (diet B) did not affect exocrine pancreatic secretion. This corresponds with most (Ternouth et al., 1975; Khorasani et al., 1989), but not all (Le Dréan et al., 1998), observations of studies carried out in preruminant calves. In rats, casein was found to stimulate pancreatic protein secretion more than isolated soy protein did (Hara et al., 1992). Thus, the protein source (clotting or nonclotting) did not affect pancreatic secretion in pigs fed milk replacer.
The absence of an effect of feeding sow’s milk compared with feeding milk replacer indicates that the low exocrine pancreatic secretion in suckling pigs does not arise from suppression by particular sow’s milk components that are not present in milk replacer diets. Concentrations of readily availably bioactive peptides (such as hormones, enzymes, growth factors, and lactoferrin) are high in sow’s milk but very low in milk replacer diets (Nagashima et al., 1990; De Wit and Van Hooydonk, 1996). The direct effect of those peptides or interactions with nutrient availability and release of gastrointestinal hormones could affect pancreatic secretion (Sheard and Walker, 1988; Konturek et al., 2003). In calves and dogs, bioactive products of milk digestion decrease gastric enzyme secretion (Vasilevskaya et al., 1977; Guilloteau et al., 1994). The lack of specific milk-borne bioactive peptides in milk replacer may, on the other hand, explain the increased volume of pancreatic secretion compared with sow’s milk. The substantially decreased activity or absence of antimicrobial factors, e.g., lysozyme, lactoperoxidase system, and lactoferrin, in milk replacer diets (De Wit and Van Hooydonk, 1996) may have required an increased secretion of pancreatic juice, which has considerable antimicrobial activity (Valverde Piedra and Studzinski, 1999).
The high correlation observed between protein and trypsin secretion supports the validity of using total protein secretion as an indicator for proteolytic enzyme secretion. Although the diets differed in protein-to-fat ratio, this did not affect the ratio between pancreatic protein and trypsin secretion. The average exocrine protein secretion was 4.2 mg·kg–1·h–1, which is intermediate between values found in suckling pigs (1.0 mg·kg–1·h–1; Pierzynowski et al., 1990; 1995) and those in weaned pigs (6.5 to 11.6 mg·kg–1·h–1; Rantzer et al., 1997; Botermans and Pierzynowski, 1999). Several reasons for the enhanced secretion in the current study than in suckling pigs can be suggested. First, the elevated feeding level may have required more pancreatic enzymes for digestion. Second, weaning, the subsequent surgery, and the individual housing conditions may have increased the production of glucocorticoids, which can result in an increased pancreatic enzyme secretion (Gómez et al., 1997; Botermans et al., 1999). Third, pigs fed sow’s milk did not receive milk from their own dam. The enhanced secretion may have been associated with greater antigenic properties of milk replacer diets and pooled sow’s milk than of maternal sow’s milk because antigenicity of dietary ingredients can be inhibited by increasing the secretion of pancreatic juice (Gestin et al., 1997). Finally, the feeding strategy could have increased pancreatic secretion because pigs could not interact with the feeding source. Pigs were fed at fixed times, and a cephalic phase reflex (namely, increased volume of pancreatic secretion) was observed before feeding. In the suckling period with their sow, on the contrary, meal intervals are not fixed and pigs can (partially) determine the time of feed intake, although this interaction decreases as the suckling period proceeds.
An increase in pancreatic secretion in response to intake of a milk replacer or the sow’s milk was not seen, which corresponds with observations in suckling pigs (Pierzynowski et al., 1990). In weaned pigs, feed intake increases the pancreatic protein secretion approximately 3-fold (Botermans and Pierzynowski, 1999). The high frequency of feeding, i.e., every 2 h, seems a plausible explanation for the absence of a response in pancreatic secretion because such a feeding pattern can result in a constant flow of nutrients in the gastrointestinal tract. However, it has been shown in weaned pigs (Botermans et al., 2000a) that feeding multiple small meals stimulated postprandial pancreatic secretion even more than feeding a few big meals. A second possibility is that the high digestibility of protein and fat and lack of complex carbohydrates in the sow’s milk (Cranwell and Moughan, 1989; Mavromichalis et al., 2001) and milk replacer diets explains the low level of pancreatic secretion and the absence of a response to milk ingestion. Still, this does not explain the low pancreatic secretion found when, in addition to sow’s milk, solid feed was also ingested by piglets (Pierzynowski et al., 1993). Pancreatic secretion only increased when the sow’s milk was completely replaced by the solid feed (Pierzynowski et al., 1993, 1995).
Plasma CCK and IRCT Concentrations
Plasma CCK concentrations were measured to study the involvement of CCK in pancreatic secretion in milk-fed pigs. Plasma concentrations of CCK have been observed to tightly regulate pancreatic secretion in weaned animals, directly or indirectly (Owyang, 1996; Konturek et al., 2003) but did not stimulate pancreatic secretion in young suckling pigs (Pierzynowski et al., 1990). Generally, plasma CCK concentration averaged approximately 18 pmol·L–1, which corresponds with the high values found in young suckling pigs (Pierzynowski et al., 1994) and which is considerably greater than the 2 pmol·L–1 observed in weaned pigs (Botermans et al., 1999). Correlations between the plasma CCK concentrations and the pancreatic secretion traits were very low in the current study.
Plasma IRCT concentrations were measured to evaluate the possibility of using IRCT as a less invasive indicator of exocrine pancreatic secretion in milk-fed pigs. It would be very useful to obtain an easily accessible indicator for pancreatic secretion that also allowed further exploration of the long-term relationship between pancreatic function and growth performance in pigs. Hitherto, studies about this relationship including the current study have included only a limited number of animals due to complicated surgery and collection procedures. Pancreatic duct catheterization may also affect growth performance in pigs. The low correlation coefficients found between plasma IRCT concentration and pancreatic secretion, however, indicate that plasma IRCT is not an appropriate indicator to detect variation of pancreatic trypsin (or protein) secretion in milk-fed pigs. These results correspond with the low correlation coefficients found by Rantzer et al. (1997) in weaned pigs. Plasma IRCT concentration averaged approximately 200 ng·mL–1, which was similar to values found in weaned pigs at the same age (Rantzer et al., 1997). In addition, the correlation coefficients did not increase when they were calculated for each experimental period separately, to account for the age-dependent increase of plasma IRCT (Sandström et al., 1986; Rantzer et al., 1995).
Relationship Between Pancreatic Secretion and Performance
Nutrient digestibility in pigs largely depends on pancreatic enzyme secretion. It has been shown that ligation of the pancreatic duct in pigs decreases the digestibility of protein and fat by more than 50% (Corring and Bourdon, 1977; Le Huërou-Luron and Guilloteau, 1999; Tabeling et al., 1999). In practice, however, it can be questioned whether the quantitative exocrine pancreatic secretion is truly limiting the nutrient digestibility and consequently pig growth because the amount of enzymes secreted by the pancreas is theoretically sufficient to hydrolyze 100 times the ingested amount of dietary substrates (Makkink and Verstegen, 1990). Paradoxically, several studies have demonstrated the responsiveness of the exocrine pancreatic secretion to feed components (Zebrowska and Low, 1987; Mosenthin et al., 1994; Gabert et al., 1996), and a positive, linear relationship between exocrine pancreatic secretion and daily BW gain was described (Botermans and Pierzynowski, 1999).
In accordance, it was seen in the current study that piglet growth increased with increasing pancreatic secretion. Individual pigs ingested similar quantities of sow’s milk and milk replacer per kilogram of metabolic BW, respectively, but the exocrine pancreatic secretion differed substantially between pigs. Large individual variation in pancreatic secretion was also described in weaned pigs (Rantzer et al., 1997; Botermans and Pierzynowski, 1999), but reasons for the differences between individual pigs are poorly understood. In the current study, a linear-plateau model gave a better fit of the relationship between protein or trypsin secretion with ADG or FCR than the linear model. Although the shape of the curve fit strongly depended on 1 pig that had a very high pancreatic secretion (and ADG), this may indicate that growth performance increased with increasing pancreatic secretion until a maximum is reached. Beyond the theoretical maximum, limitations other than the pancreatic enzyme secretion were restricting BW gain.
Whether the ADG increased and FCR decreased due to an increase in the nutrient digestibility cannot be determined because digestibility was not measured. It is likely, however, that the high nutrient digestibility of the ingredients in these diets and the involvement of nonpancreatic enzyme systems did not allow a sufficient margin to duplicate the growth of animals by only increasing digestibility. Alternative mechanisms for the role of the exocrine pancreas in animal growth may be important. Adding pancreatic enzymes to the feed of pancreatic duct ligated pigs increased performance in weaned pigs (i.e., a greater feed intake, ADG and a lower FCR), but more surprisingly, it also decreased the plasma concentrations of the free amino acids (Botermans et al., 2000b). Recently, Pierzynowski et al. (2005) suggested a possible mechanism for the decreased amino acid concentrations in plasma, which involves an intraluminal regulation of systemic amino acid and peptide availability. Briefly, the pancreatic endopeptidases are thought to bind certain amino acids and form new peptides according to the plastein reaction (in vitro: e.g., Lorenzen et al., 1997). These peptides can possess antibacterial activity and are, unlike free amino acids (Stoll et al., 1998), not extensively oxidized during their first-pass metabolism. This scenario requires sound experimental evidence and should be considered as only one of the many possible links between the exocrine pancreatic secretion and pig performance. Harada et al. (2003), for example, suggested that the growth retardation in pigs was associated with a simultaneous impairment of the exocrine and endocrine pancreatic function, which basically involves an interaction between the 2 functional parts of pancreas. The importance of the exocrine pancreas for growth has been studied in several experiments by ligation of the pancreatic duct. In young pigs, up to 12.5 kg of BW, ADG was reduced by 100% after ligation of the pancreatic duct (Imondi et al., 1972; Pitkaranta et al., 1989; Gewert et al., 2004; S. G. Pierzynowski, unpublished data). The effect of duct ligation on growth generally decreased with increasing BW: –50% at 14 kg of BW (Saloniemi et al., 1989), –65% at 25 kg of BW (S. G. Pierzynowski and J. J. G. C. van den Borne, unpublished data), and –25% at 40 kg of BW (Corring and Bourdon, 1977). Accordingly, in adult humans, 90% of the exocrine pancreas can be damaged without an impaired digestion (Layer and Holtmann, 1994), which may indicate that the exocrine pancreatic secretion can be more important for growth in the young than in mature or adult subjects.
In conclusion, the current study shows that the exocrine pancreatic protein secretion did not differ in pigs fed sow’s milk or milk replacer. The protein source (clotting vs. nonclotting protein) in milk replacer did not affect pancreatic secretion in milk-fed pigs. The pancreatic enzyme secretion showed a positive relationship with ADG in milk-fed pigs. Mechanisms involved in the relationship between pancreatic enzyme secretion and growth performance remain to be studied.
|
Footnotes |
|---|
2 These authors contributed equally to this work.
3 Corresponding author: joost.vandenborne{at}wur.nl
Received for publication April 16, 2006. Accepted for publication August 5, 2006.
|
LITERATURE CITED |
|---|
|
TopAbstractINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
This article has been cited by other articles:
|
|
 |
|
  C. J. Mader, Y. R. Montanholi, Y. J. Wang, S. P. Miller, I. B. Mandell, B. W. McBride, and K. C. Swanson Relationships among measures of growth performance and efficiency with carcass traits, visceral organ mass, and pancreatic digestive enzymes in feedlot cattle J Anim Sci, April 1, 2009; 87(4): 1548 - 1557. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
