|
|
||||||||
ANIMAL PRODUCTION |
The Ohio State University and The Ohio Agricultural Research and Development Center, Columbus 43210-1095
| Abstract |
|---|
|
|
|---|
Key Words: Diets Lactose Pigs Weaning
| Introduction |
|---|
|
|
|---|
Dried whey is a major feed ingredient added to weanling pig diets that has been shown to increase pig growth (Graham et al., 1981
, Tokach et al. 1989
; Mahan, 1993
; Nessmith et al., 1997
). Although high protein digestibility and high AA quality enhances the value of whey, its lactose seems to be a primary factor in achieving good performance responses from this product (Mahan, 1992
). Most researchers have, however, incorporated it only during the early phase after weaning. This series of experiments evaluated the effects of diet complexity and the effects of various dietary levels of lactose provided during each of three commonly used starter phases on weanling pig performance.
| Materials and Methods |
|---|
|
|
|---|
Four experiments were conducted at The Ohio State University Swine Research Farm in Columbus. The crossbred pigs ([Yorkshire x Landrace] x PIC 280) used in each experiment were weaned at an average 19 ± 2 d of age, allotted on the basis of weight, sex, and litter, and immediately placed in nursery pens (n = 5 per pen) that provided 0.30 m2 of woven-wire floor space per pig, one nipple waterer, and a four-hole stainless steel feeder. Diets were mixed in a horizontal paddle drum mixer at the Ohio Agriculture Research Center feed mill in Wooster in meal form, preweighed into bags, transported to the Columbus Swine Farm, and fed to pigs within 30 d of mixing. All diets met or exceeded NRC (1998)
nutrient requirements. The room temperature was initially set at 28°C and adjusted downward as needed to meet the comfort zone of the pigs.
Experiment 1
A randomized complete block (RCB) experiment conducted in nine replicates used a total of 135 crossbred pigs and evaluated the effects of diet complexity during both d 0 to 14 and d 14 to 28 postweaning. Diets were formulated with various combinations of protein sources for each treatment group during each of two nursery phases. All diets contained corn and soybean meal, but the percentage of soybean meal was reduced as the diets became more complex. In the initial d-0 to -14 period, the complex treatment diet contained dried whey, blood cells, soy protein concentrate, blood plasma, fish meal, and synthetic AA (lysine and methionine). A second treatment diet (semicomplex) contained dried whey and blood plasma, whereas the third treatment group (simple diet) was formulated with corn and soybean meal. During d 14 to 28, the diets contained the same ingredients as in the initial phase except that plasma protein was eliminated in the d-0 to -14 period of the complex and semicomplex diets, and the percentage of contribution from each protein source varied from the initial phase. The calculated lysine (total) content of diets was 1.55 and 1.45% during the initial 0- to 14- and 14- to 28-d periods, respectively. Because of the presence of ileitis in the herd, a high level of antibiotic was included in the nursery diets as a preventative for the disease. The composition of treatment diets is presented in Table 1
. Pig weights and feed intake were recorded at 7-d intervals during the experiment.
|
A RCB experiment conducted in eight replicates evaluated the effect of lactose (total) levels during the initial period postweaning. A complex dietary scheme similar to that followed in Exp.1 was provided during d 0 to 14 postweaning (Table 2
). Lactose (total) levels ranged from 10 to 35%, in 5% increments, in six treatment groups. Lactose was provided from dried whey (70% lactose), with crystalline lactose added to attain the desired dietary lactose (total) treatment levels. Lactose was added at the expense of corn, with corn gluten meal also added to replace the corn protein component lost from this replacement. From d 14 to 30 postweaning, the pigs were fed a common diet containing 17% lactose (total). This part of the experiment was conducted to evaluate whether the lactose levels provided during the initial period could affect and influence later growth and feed intake responses. The composition of the basal diet for the 0- to 14-d period and the common diet during the second phase is presented in Table 2
. A total of 240 crossbred pigs was allotted to treatment pens with pig weights and feed intakes collected at d 7, 14, and 30 of the experiment.
|
The length of feeding the Phase 1 diet in most commercial and research conditions is normally 5 to 14 d after weaning. The pigs of this experiment were fed a 25% lactose diet during the initial week postweaning, whereupon this experiment was initiated. Lactose (total) levels ranging from 7 to 31%, in 5% increments, in six treatment groups were evaluated during the 7- to 21-d postweaning period. Dried whey was included in all treatment diets at 10% (i.e., 7% lactose), with crystalline lactose added to attain the desired treatment lactose (total) levels. The replacement of the added lactose to the diets was the same as in Exp. 2 by using lactose and corn gluten meal at the expense of the corn component. The composition of the basal diet is presented in Table 2
. This RCB experiment was conducted in 11 replicates and involved a total of 330 pigs. Pigs were allotted at weaning into the six treatment pens with the lactose treatment diets started on test at d 7 postweaning. Subsequent pig weights and feed intakes were collected at 7-d intervals to 21 d postweaning.
Experiment 4
Pigs used in this experiment were fed a 25% lactose diet from 0 to 7 d postweaning, followed by a 17% lactose diet that was fed from 7 to 21 d after weaning, similar in composition to the diets of Exp. 2 and 3. Pigs were allotted to one of five treatment pens at 21 d postweaning. A total of 300 crossbred pigs was used in a RCB experiment conducted in 12 replicates to evaluate the effect of providing five lactose levels ranging from 0 to 20% lactose (total) in 5 % increments from 21 to 35 d postweaning. The basal diet was comprised of corn and soybean meal with no added lactose. Crystalline lactose was added to treatment diets at the expense of corn, with corn gluten meal added to replace the corn protein component removed by the lactose addition. The composition of the basal diet is presented in Table 2
.
Statistical Methods
The performance responses within each experiment were analyzed as a RCB design (Steel and Torrie, 1980
) using the MIXED procedure of SAS (SAS Inst., Inc., Cary, NC). In all experiments, time was included in the model because replicates in each experiment were not conducted within the same group. In Exp. 1, treatments were contrasted by LSD after a significance level of P < 0.05 was obtained from the ANOVA. In Exp. 2, 3, and 4, regression analysis was conducted for the different lactose levels evaluated. In Exp. 4, the initial BW differed by replicate. It was of interest to know whether lighter weight pigs responded to the dietary lactose levels as those of a heavier BW. Consequently, seven replicates of pigs averaged 15.0 ± 0.8 kg at 21 d of age, and five replicates of pigs averaged 17.7 ± 0.9 kg BW and were analyzed separately. In each experiment, the pen was considered the experimental unit.
| Results |
|---|
|
|
|---|
Daily gains increased during each postweaning period when the starter diets became more complex (Table 3
). Feeding the complex diet resulted in greater (P < 0.05) gains during both d 7 to 14 and d 14 to 21, and for the overall period of 0 to 28 d. Although there was a numerical decline in daily gain response during the initial week when the simple diet was fed, the data did not differ significantly between the three treatment groups. Daily feed intakes were greater as diet complexity increased during d 0 to 7 (P < 0.05), d 14 to 21 (P < 0.05), and for the overall period of d 0 to 28 (P < 0.05), but not during d 14 to 28. Feed efficiency was greater (P < 0.05) during d 0 to 14, for the overall 0- to 28-d period (P < 0.05), but not for d 14 to 28. At 28 d postweaning, pigs fed the complex diet were 2.65 kg heavier (i.e., 12%) in BW (P < 0.05) than pigs fed the simple diet, whereas those fed the semicomplex diet had BW intermediate to the other two treatment groups.
|
This experiment evaluated the effect of feeding a complex diet at dietary lactose levels ranging from 10 to 35% during the initial period postweaning, followed by the feeding of a common 17% dietary lactose (total) level from 14 to 30 d postweaning. The results presented in Table 4
indicated that daily gains increased linearly (P < 0.05) as dietary lactose level increased from d 0 to 7 and from d 0 to 14. Gain increased to the 30% lactose level but decreased at the 35% lactose level. There was no treatment group effect from d 7 to 14. Although feed intake numerically increased during d 0 to 7 and d 7 to 14 with dietary lactose level, the responses for each weekly period and for the period from 0 to 14 d were not significant. There was a linear increase (P < 0.05) in feed efficiency to lactose level during the 0- to 7-d period, but not during the subsequent week.
|
Experiment 3
Pigs were fed a common complex diet containing 25% lactose during the initial week postweaning, whereupon various dietary treatment lactose levels added to a complex diet were fed during the ensuing 14-d postweaning period. Responses presented in Table 5
demonstrated that daily gains increased in a linear (P < 0.01) manner during the period from d 7 to 14, whereas gains during d 14 to 21 also tended to be greater (P < 0.10) when lactose levels increased. For the overall 7- to 21-d period, gains increased (P < 0.01) as lactose level increased, with a response plateau suggested at about 17% lactose. Feed intakes tended to be greater (P < 0.10) during the period of d 7 to 14 as dietary lactose level increased. Gain:feed ratio increased linearly (P < 0.05) for the 7- to 21-d period as dietary lactose level increased.
|
Pigs were fed common complex diets containing 25 and 17% lactose levels during the d-0 to -7, and d-7 to -21 periods, respectively. During the 21- to 35-d experimental period, the diets were comprised of a corn-soybean meal mixture with lactose added at levels ranging from 0 to 20%. Crystalline lactose was added at the expense of corn, with corn gluten meal replacing the corn protein component. The results presented in Table 6
demonstrated that daily gains were greater (P < 0.05) as lactose level increased with a plateau suggested at the 15% lactose level. Daily feed intake increased (P < 0.05) to the 20% lactose level. There was no effect on feed efficiency to added lactose level during the period form d 21 to 35.
|
| Discussion |
|---|
|
|
|---|
21 d of age, the pigs ability to effectively respond with its immune system is lower (Blecha et al., 1983
The effect of varying the complexity of diets fed to nursery pigs (Dritz et al., 1996
; Whang et al., 2000
; Wolter et al., 2003
) and measuring the subsequent responses to market weight have resulted in responses that have been inconsistent. Some reports have indicated that diet complexity during the starter phase has had no effect on the length of time until grower-finisher pigs reach market weight (Dritz et al., 1996
; Whang et al., 2000
; Wolter et al., 2003
), whereas others have shown that lighter-weight pigs at the end of the starter phase reach market weight at an older age (Chiba, 1995
; Dritz et al., 1996
). A tendency for a greater variation in pig weights by market weight has been reported when a simple nursery diet had been fed (Wolter et al., 2003
). Our results demonstrated a 2.65 kg or an approximate 12% difference in BW at the end of a 28-d starter period when a complex vs. a simple diet was fed to 28 d postweaning. However, the subsequent long-term effects of these diets to market weight were not determined in these pigs.
Lactose is a major component of dried whey and has been shown to be a primary factor in enhancing starter pig performances (Mahan, 1992
). The dietary level of lactose that was necessary to achieve maximum growth rates declined as pigs became older and heavier, probably because the pigs digestive tracts became more mature and the digestive enzymes needed to hydrolyze the more complex components in cereal grains were adequately secreted. Our results suggest that lactose probably has a minimal carryover effect from one starter phase to another, but particularly during the early phases postweaning. When pigs in Phase 3 were fed various levels of lactose, there was a growth response to the lactose addition. Although the lighter-weight pigs in Phase 3 seemed to respond more to the dietary lactose levels than the heavier pigs, the data indicate that both groups responded in a positive manner to the lactose addition. This suggests that pigs at 21 d postweaning would probably benefit from dietary lactose to 25 kg BW, but pigs of a lighter weight would respond more than heavier weight pigs.
Lactose is the major substrate that enhances the growth of the Lactobacillus spp. (Kenworthy and Crabb, 1963
), and its presence may help to suppress some of the hemolytic coliforms and other pathogens that decrease pig performance and their health status (De Mitchell and Kenworthy, 1976
; Muralidhara et al., 1977
[C1]). The Lactobacillus spp. present in the stomach and intestinal tract of the pig at weaning may be important in continuing to maintain a healthy intestinal tract environment throughout the postweaning nursery period (Krause et al., 1995
).
Although lactose from either dried whey or crystalline lactose is beneficial during the postweaning period, other simple carbohydrates may be just as effective (Hongtrakul et al., 1998
; Oliver et al., 2002
). However, added fiber (Cheeke and Stangel, 1973
), the inclusion of fat, and the pelleting of a high-lactose diet (Cheeke and Stangel, 1972
) may reduce the effectiveness of the lactose addition on pig performances. In addition, certain breeds or genotypes may not tolerate high levels of whey or lactose, particularly if fed for an extended time (Ekstrom et al., 1976
).
For optimal performance responses, our results suggest total inclusion levels of lactose of approximately 25 to 30% during the initial week postweaning or to a BW of 7 kg, followed by an approximately 20% level during the period from d 7 to 21 or to a BW of 12.5 kg, and a 10 to 15% level from d 21 to 35 postweaning or to a BW of 25 kg. The inclusion of lactose throughout the starter period may be important in maintaining a good intestinal environment and in decreasing the variability in pig market weights as reported by Wolter et al. (2003)
. The subsequent long-term effects of these lactose levels during the grower finisher period cannot be ascertained from our experiment.
| Footnotes |
|---|
2 Appreciation is expressed to K. Mays, M. Bayes, and L. Warnock for animal care and data collection, and to B. Bishop for statistical analyses. ![]()
3 The experimental use of animals and procedures followed was approved by the University Animal Care Committee. ![]()
4 Correspondence: 2027 Coffey Rd. (phone: 614-292-6987; fax: 614-292-7116; e-mail: mahan.3{at}osu.edu).
Received for publication February 25, 2004. Accepted for publication June 1, 2004.
| Literature Cited |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
C. Hoppe, G. S. Andersen, S. Jacobsen, C. Molgaard, H. Friis, P. T. Sangild, and K. F. Michaelsen The Use of Whey or Skimmed Milk Powder in Fortified Blended Foods for Vulnerable Groups J. Nutr., January 1, 2008; 138(1): 145S - 161S. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. L. Cromwell, G. L. Allee, and D. C. Mahan Assessment of lactose level in the mid- to late-nursery phase on performance of weanling pigs J Anim Sci, January 1, 2008; 86(1): 127 - 133. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. W. Frank, J. Escobar, A. Suryawan, H. V. Nguyen, S. R. Kimball, L. S. Jefferson, and T. A. Davis Dietary protein and lactose increase translation initiation factor activation and tissue protein synthesis in neonatal pigs Am J Physiol Endocrinol Metab, February 1, 2006; 290(2): E225 - E233. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |