Effects of Replacing Lactose with Novel Carbohydrate Sources on Effects of Replacing Lactose with Novel Carbohydrate Sources on Nursery Pig Growth Performance Nursery Pig Growth Performance

Summary This experiment was conducted to determine the effects of replacing lactose in Phase 1 and 2 nursery pig diets with 1 of 2 novel carbohydrate (CHO) products (CHO-D and CHO-L; Cargill Starches, Sweeteners, & Texturizers, Blair, NE) on growth performance and fecal dry matter. A total of 360 barrows (DNA 200 × 400; initially 13.2 ± 0.10 lb) were used in a 42-d growth trial. Pigs were weaned at approximately 21 d of age, randomly allotted to pens in 1 of 2 weight blocks based on initial BW (initially 12.0 and 14.5 lb), and then allotted to 1 of 6 dietary treatments in a completely randomized design. There were 5 pigs per pen and 12 pens per treatment across 2 barns. Dietary treatments were corn-soybean meal-based with 5 to 7.5% DDGS and included: 1) negative control (NC; containing 0.08 and 0.04% lactose, phase 1 and 2, respectively); 2) positive control (PC; containing 10 and 5% lactose, phase 1 and 2, respectively); 3) 50% of lactose replaced with the dry novel CHO (50% CHO-D; containing 5 and 2.5% lactose, phase 1 and 2, respectively); 4) 100% of lactose replaced with CHO-D (100% CHO-D; containing 0.09 and 0.05% lactose, phase 1 and 2 respectively); 5) 50% of lactose replaced with the liquid novel CHO (50% CHO-L; containing 5 and 2.5% lactose, phase 1 and 2, respectively); or 6) 100%


Introduction
Milk-derived products (i.e., dried whey powder or whey permeate) are commonly included in early nursery pig diets to help transition the weaned pigs from a milk-based liquid diet to a solid, plant-based diet.However, in recent years the cost of feeding traditional lactose sources has risen exponentially, leading producers to seek alternative solutions to help acclimatize weaned pigs to solid feed.It has been demonstrated that a portion of dried whey may be replaced by non-lactose carbohydrate sources (sucrose, dextrose, etc.) without negatively impacting nursery pig performance. 4,5The Starches, Sweeteners, and Texturizers division of Cargill produces many CHO products through their corn wet-milling activities, but it is unknown whether any of the products can elicit beneficial growth performance in weaned pigs.Therefore, the objective of this study was to determine the effects of replacing increasing levels of lactose with 1 of 2 novel CHO sources on nursery pig growth performance, feed efficiency, and fecal dry matter.

Procedures
The Kansas State University Animal Care and Use Committee approved the protocol used in this experiment.The experiment was conducted at the Kansas State University Segregated Early Weaning Research Facility in Manhattan, KS.Each pen contained a 4-hole, dry self-feeder, and nipple waterer for ad libitum access to feed and water.

Animals and diets
A total of 360 barrows (DNA 200 × 400; initially 13.2 ± 0.10 lb BW) were used in a 42-d growth trial.Pigs were weaned at approximately 21 d of age, randomly allotted to pens in 1 of 2 weight blocks based on initial BW (initially 12.0 and 14.5 lb BW), and then allotted to 1 of 6 dietary treatments in a completely randomized design.There were 5 pigs per pen and 12 pens per treatment across 2 barns.Pigs were provided ad libitum access to water and to feed in a pellet form in phases 1 and 2, and meal form in phase 3. The experimental diets for phases 1 and 2 were manufactured at Provimi North America in Lewisburg, OH, while the common phase 3 diet was manufactured at Hubbard Feeds in Beloit, KS.Dietary treatments were corn-soybean meal-based with 5 to 7.5% DDGS and included: 1) negative control (NC; containing 0.08 and 0.04% lactose, phase 1 and 2, respectively); 2) positive control (PC; containing 10 and 5% lactose, phase 1 and 2, respectively); 3) 50% of lactose replaced with the dry novel CHO (50% CHO-D; containing 5 and 2.5% lactose, phase 1 and 2, respectively); 4) 100% of lactose replaced with CHO-D (100% CHO-D; containing 0.09 and 0.05% lactose, phase 1 and 2, respectively); 5) 50% of lactose replaced with the liquid novel CHO (50% CHO-L; containing 5 and 2.5% lactose, phase 1 and 2, respectively); or 6) 100% of lactose replaced with CHO-L (100% CHO-L; containing 0.09 and 0.05% lactose, phase 1 and 2, respectively).Novel CHO sources (CHO-D or CHO-L) replaced whey powder on a carbohydrate basis in phase 1 and 2 diets (Tables 1 and 2).The NC diet, as well as the 100% CHO-D and 100% CHO-L diets, contained trace amounts of lactose due to the inclusion of whey protein concentrate which was included in the diet to balance CP% across diets.Ratios of other AAs to Lys were maintained well above requirements to ensure that there were no limiting AAs.Individual pigs were weighed, and feed disappearance was recorded on d 0, 7, 10, 17, 24, 31, and 42 to determine ADG, ADFI, and feed efficiency.
Fecal samples were collected on d 10 and 24 to determine fecal dry matter percentage from the same three randomly selected pigs from each pen.After collection, fecal samples were dried at 55°C (131°F) in a forced air oven for 48 h, and the ratio of dried to wet fecal weight determined the fecal dry matter.Fecal samples were maintained separately for each pig and the average of the three samples from each pen was then used for statistical analysis.

Statistical analysis
Experimental data were analyzed using R Studio (Version 3.5.2,R Core Team, Vienna, Austria) with pen serving as the experimental unit in a completely randomized design.Treatment, body weight block, and the associated interaction served as a fixed effects within the statistical model, with barn serving as a random effect.Differences between treatments were determined using estimated marginal means.When treatment was a significant source of variation, differences were determined by the preplanned pairwise comparisons using the Tukey-Kramer multiplicity adjustment to control for type I error.Results will be considered significant at P ≤ 0.05 and marginally significant at P ≤ 0.10.

Results and Discussion
There was no main effect of CHO source (P ≥ 0.100) on BW at any weighing event (d 0, 7, 10, 17, 24, 31, 42; Table 3).However, pigs in the heavyweight block had significantly greater (P ≤ 0.001) BW than pigs in the lightweight block at each weighing event (Table 4).There were no observed weight block × CHO source interactions or main effect of CHO source (P > 0.100) on the percentage of pigs that lost weight from d 0 to 7.However, there was a tendency (P = 0.063) for a greater percentage of pigs in the lightweight block to lose weight compared to those in the heavyweight block.
Throughout the treatment period (d 0 to 24) there was a weight block × CHO source interaction (P = 0.045) for ADFI, in which heavyweight pigs fed the PC diet

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Kansas State University Agricultural Experiment Station and Cooperative Extension Service containing lactose had greater ADFI than lightweight pigs fed the same diet, while there was no significant difference due to weight block among the other treatments.There were no observed weight block × CHO source interactions or main effect of CHO source (P ≥ 0.100) on ADG.However, there was a tendency for a main effect of CHO source (P = 0.057) on feed efficiency, but the means did not separate.Moreover, pigs in the heavyweight block had greater (P < 0.001) ADG than those in the lightweight block.
During the common period (d 24 to 42), there was no observed weight block × CHO source interaction or main effect of previously fed CHO source (P ≥ 0.100) on ADG, ADFI, or feed efficiency.However, pigs in the heavyweight block had greater (P < 0.001) ADG and ADFI than those in the lightweight block, leading to poorer (P = 0.020) feed efficiency.
Overall (d 0 to 42), there was a tendency for a weight block × CHO source interaction (P = 0.067) for ADFI.There was no observed main effect of CHO source (P > 0.100) on any observed growth performance characteristic.However, pigs in the heavyweight block had greater (P < 0.001) ADG and ADFI than those in the lightweight block, leading to poorer (P = 0.033) feed efficiency.There were no observed 2-or 3-way interactions or any observed main effects of weight block or CHO source (P > 0.100) on percent fecal dry matter.
In summary, feeding either of the novel CHO sources did not significantly impact growth performance, percentage of pigs that lost weight post-weaning, or fecal dry matter during the nursery period compared with those pigs fed a traditional lactose source.Furthermore, the addition of lactose to the diet did not influence any response criteria compared to a diet without lactose.This response was not expected and prevented the ability to determine if either CHO source could replace lactose in nursery pig diets.

Brand names appearing in this publication are for product identification purposes only.
No endorsement is intended, nor is criticism implied of similar products not mentioned.Persons using such products assume responsibility for their use in accordance with current label directions of the manufacturer.Negative control (NC) containing 0.04% lactose. 3 Positive control (PC) containing 5.04% lactose.

5
Zinc oxide was included in the diet to provide 2,000 ppm of Zn. 6 Ronozyme Hiphos (GT) 2700 (DSM Nutritional Products, Inc, Parsippany NJ), provided 302,400 phytase units (FTU/lb), for an estimated release of 0.13% STTD P. 7 Ronozyme 2700 (DSM Nutritional Products) provided an assumed 0.13% release of STTD P with 567 FTU/lb inclusion in the final diet.A total of 360 barrows (initial BW = 13.2 ± 0.100 lb) were used in a growth performance study with 5 pigs per pen and 12 replicates per treatment.
2 ADG = average daily gain.ADFI = average daily feed intake.F/G = feed-to-gain ratio. 3 Negative control (NC) containing 0.075 and 0.0% lactose, phase 1 and 2, respectively.Positive control (PC) containing 10 and 5% lactose, phase 1 and 2, respectively. 4 Throughout the treatment period (d 0 to 24) there was a weight block × CHO source interaction (P = 0.045) for ADFI, in which heavyweight pigs fed the PC diet containing lactose had greater ADFI than lightweight pigs fed the same diet, while there was no significant difference due to weight block among the other treatments.

5
F/G was calculated by taking the inverse of G:F.Statistics were not run on F/G, therefore no SEM is reported and P values are the same as reported for G:F. 6Overall (d 0 to 42), there was a tendency for a weight block × CHO source interaction (P = 0.067) for ADFI. 7 Percentage of individual pigs that lost weight from d 0 to 7 per treatment.

8
A main effect of day was observed (P < 0.001). 9 No diet × day interaction (P = 0.816) was observed.A total of 360 barrows (initial BW = 13.2 ± 0.100 lb) were used in a growth performance study with 5 pigs per pen and 36 replicates per treatment.
3 F/G was calculated by taking the inverse of G:F.Statistics were not run on F/G, therefore no SEM is reported and P values are the same as reported for G:F.

Table 1 .
Composition of phase 1 diets (as-fed basis) 1 Kansas State University Agricultural Experiment Station and Cooperative Extension Service Kansas State University Agricultural Experiment Station and Cooperative Extension Service

Table 2 .
Composition of phase 2 and 3 diets (as-fed basis) 1 1Diets were fed to pigs from approximately 16 to 26 lb BW. 2

Table 3 .
Effects of carbohydrate source on nursery pig performance1,2

Table 4 .
Main effects of initial body weight block on pig performance1,2