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ANIMAL PRODUCTION |
* Department of Animal and Food Sciences, University of Kentucky, Lexington 40546; and
and
APC Company, Inc., Ankeny, IA 50021
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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Key Words: Immunoglobulin • Pig • Spray-Dried Animal Plasma
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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; Coffey and Cromwell, 2001; Van Dijk et al., 2001).
The mode of action by which SDPP increases feed intake and growth rate is not completely understood. Ermer et al. (1994) suggested that it might be due to an appetite stimulant in SDPP. Others have suggested that the positive responses might result from specific immunoglobulin proteins in the plasma that enhance growth performance (Gatnau et al., 1995; Owen et al., 1995; Weaver et al., 1995). This finding is supported by research showing that growth and feed intake responses to supplemental SDPP are greater in challenged vs. clean environments for pigs (Coffey and Cromwell, 1995) as well as broilers (Campbell et al., 2003) and turkeys (Campbell et al., 2004a).
Plasma from bovine species has been shown in some instances to be as effective as plasma from porcine species (Gatnau and Zimmerman, 1994; Russell, 1994; Russell and Weaver, 1996). Furthermore, dried bovine serum or bovine immunoglobulins have been shown to benefit poultry challenged with Pasteurella multocida (Campbell et al., 2004b).
The objectives of this research were to assess the effects of various molecular weight fractions of spray-dried plasma from different species (porcine and bovine) on the growth performance of weanling pigs and to determine the optimal level of immunoglobulin protein from porcine and bovine plasma on performance of weanling pigs.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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Crossbred (Hampshire x Yorkshire) pigs were used in the experiments. Pigs from a given weaning group were ranked by BW and allotted randomly to treatments within blocks. Ancestry and sex were balanced across treatments as much as possible. In Exp. 1 to 4, pigs were housed in groups of four or five pigs per pen in an off-site experimental nursery. Room temperature was maintained at approximately 33°C for the first week and then lowered 3°C/wk for the next 3 wk. Pigs in Exp. 5 were housed in groups of five to seven pigs per pen in an on-site nursery. In that nursery, room temperature ranged from approximately 24 to 38°C.
The pens in the off-site unit were elevated decks (1.5 x 1.5 m) with galvanized wire flooring over plastic flush pans. The pens in the on-site nursery were elevated decks (1.0 x 2.1 m) with plastic-coated wire flooring over a manure pit. In both nurseries, the pens were equipped with a stainless steel feeder and nipple waterer. Pigs were allowed to consume feed (meal form) and water ad libitum. Pigs were weighed individually, and feed intake was determined weekly.
The experimental diets (Table 1) consisted mainly of corn and dehulled soybean meal (SBM) with 20% dried whey and were formulated to meet or exceed all the requirements for weanling pigs from 5 to 10 kg of BW (NRC, 1998). The SBM and dried whey were included at the same level in all diets within each experiment. Soy protein concentrate (SPC) was included in the basal diets. When SDPP or SDBP were added at 8%, all the SPC and salt were deleted, and adjustments were made in the amounts of corn, corn oil, L-lysine·HCl, and DL-methionine to maintain constant levels of lysine, methionine, Na, and ME across the diets. Similarly, the plasma fractions were added at the expense of SPC, and amounts of corn, corn oil, L-lysine·HCl, and DL-methionine were adjusted to maintain constant levels of nutrients and ME across diets. Adjustments were made in the amounts of dicalcium phosphate and ground calcitic limestone to maintain a constant level of Ca and P across all diets. The diets also contained antimicrobial agents (Aureomix-500, Roche Vitamins, Parsippany, NJ) and copper sulfate (250 mg Cu/kg of diet).
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The SDPP and SDBP and the IgG fraction of each were analyzed for IgG content by American Protein Corp. using turbidimetric assay procedures (Etzel et al., 1997). Immunoglobulin concentrations ranged from 17.9 to 22.5% in the SDPP and were 16.0 and 16.6% in SDBP (Table 2). The IgG in the IgG-rich fractions was 2.0 to 3.7 times as concentrated as that in the dried plasma (Table 2).
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) using an N analyzer (Foss Heraeus, UIC Inc., Joliet, IL).
Experiment 1
Eighty pigs initially averaging 5.6 kg and 21.0 d of age were used in a 28-d experiment to evaluate SDPP and three molecular weight fractions of SDPP, which consisted of an IgG-rich fraction, an albumin-rich fraction, and a low molecular weight fraction. The pigs were in groups of four pigs per pen, and there were four pen-replicates per treatment. Diet 1 consisted of corn, SBM, spray-dried whey, and SPC and was formulated to contain 1.41% lysine (Table 1
). In diet 2, 8.0% SDPP was added. The IgG-rich fraction was included in diet 3 at 3.57% such that the amount of IgG in diet 3 was equal to the amount of IgG contributed by the SDPP in diet 2. This amount was based on the IgG-rich fraction containing 50.5% IgG and the SDPP containing 22.5% IgG (Table 2). The same procedure was used to determine the amount of albumin-rich fraction that was added to diet 4. The albumin-rich fraction contained 89% albumin, and the SDPP contained 48% albumin. Therefore, 4.32% of the albumin fraction was included in diet 4. Diet 5 was formulated to contain 200% of the level of low molecular weight fraction found in the SDPP, which contained only 0.46% of this fraction. The low molecular weight fraction was considered to be 100% pure, so the level of the fraction added to the diet was 0.074%. The diets were fed throughout the 28-d test period.
Experiment 2
A 21-d experiment was conducted using 80 pigs initially averaging 6.3 kg of BW and 21.3 d of age to determine the dietary level of porcine IgG that would optimize growth performance in weanling pigs. Diets 1 and 2 were approximately the same as in Exp. 1 (Table 1). The IgG-rich fraction was included in diets 3, 4, and 5 at 1.25, 2.50, and 3.75%, respectively. The levels of IgG provided by the IgG-rich fraction represented 40, 80, and 120% of the IgG provided by the SDPP in diet 2. The diets were fed throughout the 21-d test period. There were four pen replicates of four pigs per pen for each treatment.
Experiment 3
Ninety-five pigs initially averaging 5.3 kg of BW and 14.8 d of age were allotted randomly to five dietary treatments in a 28-d experiment to determine the dietary level of porcine IgG for optimizing growth performance in very early weaned pigs. Diets 1 and 2 were similar to those used in Exp. 1 and 2, except that the diets were formulated to contain 1.5% lysine (Table 1). The IgG-rich fraction was included in diets 3, 4, and 5 at 1.38, 2.76, and 4.14%, respectively. The levels of IgG provided by the IgG-rich fraction represented approximately 64, 128, and 192% of the IgG provided by the SDPP in diet 2. The diets were fed throughout the 28-d test period. Pigs were housed four or five pigs per pen with four pen replicates per treatment.
Experiment 4
A 28-d experiment was conducted with 95 pigs initially averaging 5.6 kg of BW and 19.7 d of age to compare the growth response of pigs fed SDPP or SDBP and to assess the effect of two dietary levels of bovine IgG for early weaned pigs. Diet 1, the control, consisted primarily of corn, SBM, spray-dried whey, and SPC (Table 1). In diets 2 and 3, respectively, SDPP or SDBP was added at 8.0% of the diet. The bovine IgG-rich fraction was included in diets 4 and 5 at levels of 1.07 and 2.14%, respectively. These levels of IgG-rich fraction provided 50 and 100% of the IgG that was supplied by the SDBP in diet 3. These diets were fed for 14 d, after which the pigs were fed a common diet that did not contain SDPP, SDBP, or the IgG fraction for the final 14 d of the experiment. The common diet consisted primarily of corn, SBM, dried whey, and SPC and was formulated to contain 1.20% lysine (Table 1). There were four or five pigs per pen with four pen replicates per treatment.
Experiment 5
One hundred fifty-two pigs, averaging 6.4 kg of BW and 22.5 d of age, were used in a 28-d experiment to evaluate SDBP, SDPP, and two levels of bovine IgG-rich fraction for early weaned pigs housed in a conventional on-site nursery. The same two dietary levels of bovine IgG used in Exp. 4 were evaluated (Table 1). The diets were similar to those used in Exp. 4 with the exception of the levels of bovine IgG. The percentages of bovine IgG-rich fraction were increased to 2.03 and 4.06% because of a lower concentration of IgG in the IgG-rich fraction (Table 2). These two levels of the IgG-rich fraction provided 50 and 100% of the IgG supplied by the SDBP in diet 3 (Table 2). The diets were fed for 14 d, after which the pigs were fed the same common diet used in Exp. 4 for the final 14 d of the experiment. There were five pen replicates of six pigs per pen for each treatment.
Statistical Analyses
The data from each experiment were analyzed as a randomized complete block design (Snedecor and Cochran, 1989) using the GLM procedures of SAS (SAS Inst., Cary, NC). Treatments were deemed sufficiently unrelated in Exp. 1, 4, and 5 that means were separated by LSD. Treatment means in Exp. 2 and 3 were assessed using preplanned contrasts of control vs. SDPP, control vs. mean of IgG-rich fractions, SDPP vs. mean of IgG-rich fractions, and linear and quadratic trends within the three IgG-rich fractions. In all experiments, pen was considered the experimental unit. Unless stated otherwise, an 
level of <0.05 was considered statistically significant.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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). Similarly, inclusion of the IgG-rich fraction during wk 1 resulted in improvements (P < 0.05) in ADG and ADFI compared with controls; means were not significantly different from those of pigs fed SDPP. Feed:gain responses also tended to improve in pigs fed SDPP or the IgG-rich fraction compared with the controls, but the differences were not significant. Performance by pigs fed the albumin or low molecular weight fraction during the first week of the test did not differ significantly from controls.
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Experiment 2
Pigs fed the diet containing SDPP grew faster (P < 0.05) and consumed more feed (P < 0.05) than those fed the control diet during the first week of the experiment (Table 4). Similarly, feeding the IgG-rich fraction resulted in greater weight gains and feed intakes compared with those of control pigs (P < 0.05). During this period, ADG seemed to maximize at the intermediate inclusion rate of the IgG-rich fraction even though only the linear component was significant (P < 0.05). Feed:gain was not affected by dietary treatment during wk 1.
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Experiment 3
In this experiment, the addition of SDPP to the diet during wk 1 did not increase feed intake or growth rate significantly (Table 5); however, by the end of the second week, improvements in ADG and ADFI were evident from SDPP inclusion. Inclusion of the IgG-rich fraction of porcine plasma resulted in increased (P < 0.05) growth rate at the end of wk 1, wk 2, and at termination of the 4-wk study. Feed:gain of pigs fed the IgG fraction was less (P < 0.05) than for those fed SDPP at the end of wk 1 and 2 of the study, but these differences were not evident at the end of the study.
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Experiment 4
Pigs fed SDPP grew faster, consumed more feed, and were more efficient (P < 0.05) than pigs fed the control diet during the first week of the test (Table 6). The same effects for growth rate and feed intake continued (P < 0.05) through the second week. The ADG and feed intake responses to SDBP through wk 1 and 2 were less pronounced than for SDPP (P < 0.05), and the responses to SDBP did not differ (P = 0.10) from controls. However, improvements (P < 0.05) in ADG and feed:gain occurred when the bovine IgG-rich fraction was added to the diet during wk 1, and these trends continued over the initial 2-wk period. The higher bovine IgG treatment level resulted in slightly faster growth rates and feed intakes than the lower bovine IgG level, but the differences were not significant.
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Experiment 5
During the first week, pigs fed SDBP, SDPP, or the two levels of the bovine IgG-rich fraction grew faster, consumed more feed, and had lower feed:gain than pigs fed the control diet (P < 0.05; Table 7). The two sources of plasma did not differ significantly, nor did the two levels of the IgG-rich fraction differ significantly for any of the performance traits during wk 1; however, pigs fed the IgG-rich fraction consumed less feed than those fed SDPP or SDBP during this period (P < 0.05). Similar trends in ADG, ADFI, and feed:gain continued through the second week of the experiment, but some of the differences were not significant.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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and Gatnau et al. (1989) have stimulated much research over the past decade. Reviews of numerous research studies have clearly shown that SDPP enhances growth and feed intake by young pigs (Coffey and Cromwell, 2001; Van Dijk et al., 2001). In our study, SDPP produced superior growth and feed intakes during the first week in four of the five experiments compared with pigs fed the control diet. The improvement in ADG over controls during wk 1 ranged from 63 and 68% in Exp. 1 and 2 to 108 and 110% in Exp. 4 and 5, respectively. There was also an overall improvement in ADG of 67%, averaged across all five experiments. During this same period, ADFI also increased by an average of 52%. Through wk 2 (0 to 14 d) of the studies, ADG and ADFI increased by an average of 27 and 33%, respectively, in pigs fed SDPP. Feed:gain was not consistently affected by SDPP, but feed efficiency was improved in pigs fed SDPP during wk 1 in the last two experiments. The additional BW gain from feeding SDPP compared with controls during wk 1 was maintained to the end of the study only in Exp. 4. The improvements in ADG and ADFI from feeding SDPP immediately after weaning are consistent with those of other research (Kats et al., 1994; Coffey and Cromwell, 2001; Van Dijk et al., 2001).
Identification of Plasma Component Responsible for Increased Performance
Experiment 1 was designed to identify the molecular weight fraction of SDPP that is responsible for the postweaning growth enhancement in early weaned pigs. Of the three molecular weight fractions tested, only the IgG-rich fraction resulted in increased ADG and ADFI (P < 0.05) that were similar to those of pigs fed SDPP during the first week of the experiment. Neither of the other two fractions tested improved growth performance. The results clearly indicated that the initial growth response to SDPP was associated with the contribution of the IgG-rich fraction and not the albumin-rich or the low molecular weight fractions of plasma.
Significant improvements in ADG and ADFI from feeding the porcine IgG-rich fraction also were evident at the end of wk 1 and 2 in Exp. 2 and 3; growth responses (averaged across levels) were superior to those of pigs fed SDPP. In Exp. 2, the additional BW gain of pigs fed the IgG-rich fraction over controls during wk 1 (670 g) was maintained through wk 2 (905 g) and to the end of the study (784 g). Similar responses were evident in Exp. 3 with earlier weaned pigs (331, 1,120, and 1,101 g of BW gain advantage through wk 1, 2, and 3, respectively). These improvements are attributable to the continuous source of immunoglobulins until the pig is capable of synthesizing its own immunoglobulins (Wilson, 1974). Milk-derived immunoglobulins added to milk replacers have been shown to increase growth performance following gut closure in early weaned pigs (Leibbrant et al., 1987).
Evaluation of Porcine IgG Levels
Numerous studies have shown that growth performance is maximized with approximately 8% SDPP in the diet (Gatnau and Zimmerman, 1992; Owen et al., 1995; Coffey and Cromwell, 2001), which is the level of SDPP that we used in our study. For that reason, we selected levels of IgG that were below and above the amount of IgG that was provided by 8% SDPP (i.e., 40, 80, and 120% of the IgG in SDPP in Exp. 1; and 64, 128, and 192% of the IgG in SDPP in Exp. 2). The results of Exp. 2 indicate that pigs responded favorably to the addition of 80% of the porcine IgG found in the 8% SDPP diet with essentially no further improvement resulting from feeding a higher level of IgG (i.e., 120% of the IgG in the 8% SDPP diet). In Exp. 3, with younger pigs weaned at 14 d of age, the improvements in ADG and ADFI to IgG inclusion were more pronounced than in Exp. 2 with pigs weaned at 21 d, and the responses seemed to maximize at the 128% level of IgG. In both experiments, the early response to the IgG fraction was not lost as the experiment progressed in time, as was observed with the intact plasma product. Averaged across the three levels of IgG and the two experiments, the advantage in BW gain of pigs fed the porcine IgG fraction compared with controls was 501 g during wk 1, 1,013 g by the end of wk 2, and 943 g for the entire test.
These results confirm the earlier suggestion by Gatnau et al. (1995) and others that the positive responses to SDPP may result from specific immunoglobulin proteins, and they help to explain why greater responses to SDPP occur in a challenged vs. clean environment for pigs (Coffey and Cromwell, 1995) and poultry (Campbell et al., 2003, 2004a).
Evaluation of SDBP
Another objective of our study was to further determine whether there was a species-specific response to spray-dried plasma. Three recent reports suggested that there were no differences between responses of pigs fed diets containing SDBP or SDPP for 2 wk after weaning (Gatnau and Zimmerman, 1994; Russell, 1994; Russell and Weaver, 1996), whereas other studies (Hansen et al., 1993; Rantanen et al., 1994; Smith et al., 1995) indicated that SDBP was not as effective as SDPP.
Experiments 4 and 5 were conducted to compare the relative efficacy of SDBP and SDPP. Experiment 4 was conducted in the same experimental, off-site nursery that housed the pigs in Exp. 1, 2, and 3, whereas Exp. 5 was conducted in an on-farm facility with relatively continuous pig flow. In Exp. 4, pigs fed SDPP grew faster and consumed more feed than those fed SDBP during the first 2 wk of the experiment (P < 0.05). Similar trends occurred in Exp. 5, but the differences in ADG and ADFI between pigs fed the two plasma sources were not significant. Following the feeding of a common diet for 2 wk, however, the ADG and ADFI responses for the entire 4-wk period were in favor of SDBP vs. SDPP (P < 0.05 for ADFI). The additional BW gains by pigs fed plasma initially were maintained through wk 2 and to the end of the test period in Exp. 4 (SDPP = 749 g for wk 1, 1,302 g for wk 1 and 2, and 1,120 g for entire test; SDBP = 294, 280, and 420 g, respectively) but only for the SDBP treatment in Exp. 5 (SDPP = 672, 518, and –784 g; SPBP = 490, 560, and 644 g, respectively).
The results of these two experiments suggest that the type of environment may affect the relative response to SDPP or SDBP. In the off-site nursery (cleaner environment), there tended to be an advantage in the SDPP compared with the SDBP, whereas there was essentially no difference in the two sources of plasma in the on-site nursery except for an ADFI advantage following the feeding of a common diet for pigs previously fed the SDBP for the initial 2 wk. However, because the two environments were not replicated over time, no statistical evaluation of a possible interaction could be made.
Evaluation of Bovine IgG Levels
The use of IgG from SDBP in early weaned pig diets had not been previously researched at the time of this study. Based on the results of Exp. 1 that the IgG fraction of SDPP is responsible for the increase in growth rate and ADFI in early weaned pigs, we expected that the IgG fraction of SDBP might be as effective as the intact SDBP product during the early post-weaning period. The results of the two final experiments indicated that the bovine IgG-rich fraction was effective in improving growth rate and feed intake during the early postweaning period. In both experiments, the inclusion of the bovine IgG-rich fraction at 50% of the IgG level provided by 8% SDBP was as effective as 100% of the IgG level with respect to improvements in ADG and ADFI during wk 1 and through wk 2. The performance resulting from bovine IgG inclusion was superior (P < 0.05) to that of SDBP in Exp. 4 but not in Exp. 5. Averaged across both experiments and both levels of IgG, the BW gain advantage of treated pigs over controls during wk 1 (567 g) was maintained through wk 2 (809 g) and to the end of the study (1,022 g).
In a review, Coffey and Cromwell (2001) concluded that it now seems that SDPP and SDBP enhance pig performance by improving the immunocompetence of the young pig, most likely mediated by the IgG component in the plasma. The IgG prevents viruses and bacteria from damaging the gut wall, thereby resulting in a more functional intestinal wall. Several studies have shown that pigs fed dried plasma have improved intestinal morphology and enzyme activity as evidenced by increased villus surface area (Gatnau et al., 1995), longer villi and a greater villus:crypt (Touchette et al., 1997; Spencer et al., 1997), and increased mucosal maltase and lactase activities (Cain et al., 1992; Gatnau et al., 1995).
In summary, from the results of these experiments, it can be concluded that porcine and bovine IgG are as effective as SDPP or SDBP with respect to stimulating growth rate and feed intake and thereby potentially decreasing the postweaning growth lag in early weaned pigs.
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Implications |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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Footnotes |
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2 Appreciation is extended to APC Co., Inc. (Ankeny, IA) for partially supporting this research with a grant-in-aid and for supplying the spray-dried plasma and the various plasma fractions. Appreciation also is extended to Consolidated Nutrition, (Decatur, IN) for providing the soy protein concentrate, to Ajinomoto Heartland LLC (Chicago, IL) for providing the L-lysine·HCl, to Degussa Corp. (Kennesaw, GA) for providing the DL-methionine, to Akey (Lewisburg, OH) for providing the vitamin premix, and to Roche Vitamins (Parsippany, NJ) for providing the antimicrobial supplement used in these experiments. Appreciation also is given to D. Higginbotham for assistance in mixing the diets and to J. Monegue, K. Mooney, and S. Carter for assistance in caring for pigs.
3 Current address: Alltech, 3031 Catnip Hill Pike, Nicholasville, KY 40356.
4 Correspondence: 609 W. P. Garrigus Bldg. (phone: 859-257-7534; fax: 859-323-1027; e-mail: gcromwel{at}uky.edu).
Received for publication March 11, 2005. Accepted for publication August 19, 2005.
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Literature Cited |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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