Final Report to Minnesota Pork Board

Final report to Minnesota Pork Board

Funded by the Pork Checkoff

Effects of phase feeding gestating and lactating sows on reproduction performance, piglet robustness at birth and post-weaning

Samuel Kofi Baidoo, Associate Professor

Southern research and Outreach Center, University of Minnesota, Waseca, MN 56093

Abstract

Effect of phase feeding versus conventional feeding wasinvestigated on sow reproductive performance for two successive parities. A total of 240 mixed parity (1-7) sows were assigned to two dietary treatments on the week of insemination. Sows were blocked by parity and had similar body weight (BW) and backfat (BF). The phase-fed sows (n = 121, BW = 227.0 ± 3.6 kg, BF = 16.5 ± 0.7 mm)received0.4%, 0.57%and 0.7 % SID lysine diets in three different periods 1(d0 (breeding) - d35), 2 (d35- d70) and 3 (d70 – d109), respectively during gestation. The control sows(n = 120, BW = 227.7 ± 3.5 kg, BF =16.3 ± 0.7 mm)were fed a 0.57% SID lysine diet throughout gestation. Sows were moved to farrowing crates on d109 and assigned two different feeding regimens in a 2 x 2 factorial arrangement. Sowswere fed a conventional lactation diet (1.0% standard ileal digestible (SID) lysine throughout lactationthroughout lactation or test diets(SID lysine 0.8%, 1.0%, and 1.2%) for phases 1(d 0-6), 2(d 7-12) and 3 (d 13 - weaning) respectively. The sows on phase feeding regimensand on control regimen received control diets during successive gestation and lactation periods. Ratios of lysine to other amino acids for sows of mixed parity were according to NRC (2012) and kept similar across all dietary treatments. Sow BW and BF were measured during the start and end of each period. Number of piglets born live, still-born, mummies; number weaned; litter weights, and wean-to-estrus interval was recorded. Serum samples collected at the start and end of first gestation and lactation were analyzed for serum amino acids concentration.

Feeding low lysine diet in first phase (d0 – d35) of gestation did not affect (P=0.227) the BW and BF changes in sow for that period. There was no effect (P> 0.05) of dietary treatments on sow body condition during both reproductive cycle. Total born, born alive, number weaned, number of mummies, stillborn and low viable piglets were not affected (P> 0.05) by dietary treatments. Litter weight gain and litter weight for each phases were not different (P> 0.05) among dietary treatments. Sows phase fed in the previous gestation and fed control diet in the previous lactation had 1 to 1.5 more (P< 0.05) piglets born alive in the subsequent parity than sows that were phase fed in the previous lactation period regardless of feeding regime in the previous gestation period.Principal component analysis of serum amino acid data revealed time-dependent difference (d0 vs d109 in gestation, d8 vs d18 in lactation).Also differences between gestation and lactation samples were also observed. However, the effects of phase feeding were not apparent.

Key words:Lysine,phase feeding, sow, litter, parity

Introduction

Sows reproductive performance in terms of numbers of piglet weaned is steadily improving. The average number of piglets weaned per sow was 7.95 in 1990 (USDA, 1990) and for 2015 production year sows on national average weaned 10.3 pigs per litter (USDA, 2015). This improvement in performance is because the sows were selected for larger litter size and higher milk production. Better nutrition for the sows demand, housing and management strategies and reproductive technologies are key to those improvements. Modern sows are selected for leaner genetics and generally have larger body size and substantially low body fat and lower appetite. This is why it is challenging to manage and feed modern high prolific sows. Thus it is imperative to do continuous feeding and nutritional assessment to fulfill their demand (Kraeling and Webel, 2015).

Nutrient requirement of sow depends upon their age, stage of growth and production. It is important to formulate diets which are appropriate for each stages to fulfill these stage dependent requirements. Proper nutrition and management during gestation and lactation prepares sow for successful reproduction throughout their lifetime (Aherne, 2010). Currently the U.S. swine industry provides a constant level of nutritional and energy allowances to sows throughout the gestation period, with approximately 10 to 12 g/d of standardized ileal digestible (SID) lysine and 6,500 to 7,200 kcal/d of metabolizable energy (ME) in entire gestation period (Goodband et al., 2013). This leads to constant amino acid: energy ratio in the diet throughout the gestation period. When the requirement for energy increases by 25 to 35% from early to late gestation that of major limiting amino acids of gestating sows increases about two-fold from early to late gestation (Goodband et al., 2013). Nitrogen retention of whole body, including maternal and fetal protein pools, increases substantially from early gestation to late gestation. This has been documented as 0.84, 0.75, 1.00, and 1.36 g/d for day 10-40, 40-65, 65-90, and 90-114 of gestation, as expressed relative to day 65-90 (NRC, 2012). The fetal protein accretion was found to increase from 0.25 to 4.63 g/ day when we compare the requirements before and after day 69 of gestation (McPherson et al., 2004). It has also been shown that protein accretion rate in average individual mammary gland of pregnant gilts increased from 0.08 g/d before day 75 of gestation to 1.05 g/d after day 75 of gestation (Ji et al., 2006). The daily nitrogen gains in primiparous sows from all maternal and fetal tissues were 40 and 103 g/d respectively, before and after day 70 of gestation (Ji et al., 2005). This information points to the need to have higher protein levels in gestating sow diets only from the 69th day.

During late gestation and early lactation sow often becomes catabolic and mobilizes both protein and fat reserve to support fetal growth and milk production (Aherne and Williams, 1992., Pluske et al., 1998). Extended catabolic condition negatively affects longevity and productivity of sows (Foxcroft et al., 1995). Feeding a single gestation ration leads to overfeeding in early gestation and underfeeding in late gestation (Moehn et al., 2012). Feeding higher levels in early gestation could deleteriously affect embryo survival, especially in gilts (Heugten, 2000) as embryo survival decreased from 82.8% to 71.9% when feeding levels were increased from 1.5kg to 3.0kg daily (Dyck et al., 1980) as this also would accrue higher feed costs. Increasing lysine level and keeping energy intake constant has been shown to improve the birth weight of litters (Heo et al., 2008; Yang et al., 2008; Zhang et al., 2011)

Phase feeding of gestation sows is suggested to be a better management and nutritional practice to accommodate sow’s nutrient requirements and improve efficiency of sow productivity (review by Kim et al, 2013; Goodband et al., 2013; Moehn and Ball, 2013). However the sow production criteria has not been tested therefore a three phase sow feeding program; phase 1 (d 0- d35 of gestation), phase 2 (d 35- d 70) and phase 3 (d70-109) based on lysine level and balanced for other essential amino acid is expected to provide appropriate nutrition by closely matching nutrient need of the sow as well as the developing fetus.

As lactation progress, the milk production of sows also increases and peaks around third or fourth week of lactation which increases the demand for lysine (Noblet and Etienne, 1987). Modern sows wean more piglets than conventional sows with increase in the number of functional mammary glands (Kim et al., 2013). In this regard lactating sows will need additional nutrient supply not only to support the higher litter size but also for the growth of these mammary glands (Kim et al., 2013). It is reported that the mammary gland in sows continues to grow after farrowing with the increase in number of mammary epithelial in third and fourth week of lactation (Kim et al 1999). In order to meet the protein and lysine requirements of the lactating sow, Aherne, (2001) suggested that dietary protein (lysine) level should be 17.7 (0.97), 18.6 (1.00), 21.0 (1.12), and 21.4 (1.13) % in weeks 1, 2, 3, and 4 of lactation, respectively. To our knowledge, there is no reported information on phase feeding lactating sows. In order to maximize the amino acid intake during the peak lactation period when the demand is high, sows in this study were subjected to lactation feeding regimen; phase 1 (d 0- d6 of gestation), phase 2 (d 7- d 12) and phase 3 (d12-d 18) based on lysine level and balanced for other essential amino acid was studied.

Objectives

To evaluate the effects of phase feeding based on dietary lysine to multiparous gestating and lactating sows on sow and litter performanceand piglet survivability.

Specific objectives:

1. To determine the effect of phase feeding dietarylysine to multiparous gestating and lactating sows on farrowing rate, sow body weight and backfat changes, wean-to-breed interval, litter size and weight and piglet survivability at birth and at weaning for the present and subsequent parity.

1. To determine the effect of phase feeding dietary lysine to multiparous gestating and lactating sows on plasma metabolomicsduring the period of gestation and lactation.

Procedures

The experimental protocols used in this study were approved by the University of Minnesota Institutional Animal Care and Use Committee.

Animals and Management

The experiment was conducted in the swine research unit at the University of Minnesota’s Southern Research and Outreach Center in Waseca, Minnesota. A total of 240 mixed parity (1-7) sows (English Belle, GAP Genetics, Winnipeg, Manitoba, Canada) in six batcheswere used in the study. Sows were housed in individual stalls (0.61 m × 2.13 m) with an individual feeder and drinker from breeding until d 35 of pregnancy. Sows were fed once daily at 0730 h daily using automated trickle feeding system. Sows were moved to group pens (6.7 m × 12.8 m) on d 36, where they stayed until d 109 and were fed individually using electronic feed station (EFS, Osborne Industries, Inc., Osborne, Kansas). All sows were fed 1.81 kg from d 0 to d 56, 2.04 kg from d 56 to 84, 2.26 kg d 84 to d 96 and 2.5kg from d 96 to d 109 of gestation.

Sows were moved to farrowing crates (2.13 m long × 0.97 m high × 0.66 m wide) on d109 of gestation and were fed 2.27 kg of their assigned lactation diet starting on d 109 of gestation until farrowing. Post farrowing, the feed allowance was gradually increased to allow ad libitum feed intake of their lactation diet from day 4 until weaning. Sows were fed twice daily at 0800 h and 1500h. Piglets from the same dietary treatment groups were cross-fostered within 24 hours of birth and standardized to 12 pigs per sow. All piglets were processed (iron dextran injection, tail docking and navel disinfection) within 24 h of birth and surgical castrations performed on all male piglets around 1 week of age following the farm standard management practice. Heat lamps were provided around the time of farrowing till 48 h after birth. Piglets had access to heat pads in farrowing crate until weaning. Piglets with low birth weight (< 0.82 kg) were considered low viable (LV) piglets and were euthanized using CO2 chamber. Reasons for piglet mortality were recorded. The average lactation length in the farm was 19 days. After weaning sows were moved to individual crates and were checked daily for signs of estrus using mature boars. Sows were allowed free access to water throughout the study period.

All sows and piglets were monitored daily for general health and appropriate environment following sow gestation and lactation facility protocol approved in by University of Minnesota Institutional Animal Care and Use Committee.

Dietary treatment

Sows were blocked by parity, body weight, and backfat thickness at breeding and assigned one of thetwo dietary treatments during the gestation period in a randomized complete block design. Diets were formulated on standardized ileal digestible (SID) AA basis. The phase-fed sows (n = 121, BW = 227.0 ± 3.6 kg, BF = 16.5 ± 0.7 mm)received 0.4%, 0.57%and 0.7 % SID lysine diets in three different periods 1(d0 (breeding) - d35), 2 (d35- d70) and 3 (d70 – d109), respectively during gestation. The control group sows(n = 120, BW = 227.7 ± 3.5 kg, BF =16.3 ± 0.7 mm)were fed a 0.57% SID lysine diet throughout gestation. Sows were moved to farrowing crates on d109 and assigned to two different lactation feeding regimen in a 2 x 2 factorial arrangement (two level of gestation and two levels of lactation diet). Half of the sows from each gestation treatment group were assigned one of the two lactation treatment. During lactation period, control sows were fed a conventional lactation diet (1.0% standard ileal digestible (SID) lysine, 18% CP) throughout lactation or test diets(SID lysine 0.8%, 1.0%, and 1.2%) for phases 1(d 0-6), 2(d 7-12) and 3 (d 13 - weaning) respectively. All sows on were fed conventional control diets during successive gestation and lactation periods. Ratios of lysine to other amino acids for sows of mixed parity were according to NRC (2012) and kept similar across all dietary treatments.

Gestation Period Feed Regimen:

• Control: single-phase feeding 0.57% standardized ileal digestible (SID) lysine

• Treatment: three-phase feeding (0.4% SID lysine for day 0-35 of gestation, 0.57% SID lysine for day 35-70 of gestation; 0.7% SID lysine for day 70-109 of gestation)

Lactation Period Feed Regimen:

• Control: single-phase feeding 1.0% SID lysine

• Treatment: three-phase feeding (0.80% SID lysine for day 0-6 of lactation; 1.00% SID lysine for day 6-12 of lactation; 1.20% SID lysine for day 12-18 of lactation)

Data Collection

Feed sample analysis

Feed samples for each batch of all dietary treatments during gestation and lactation were collected; mixed and representative samples were used for analysis. Concentration of AA (AOAC 2006; method 982.30 E) and CP (AOAC 2006; method 990.03) in diet samples were analyzed at Experiment Station Chemical Laboratories (University of Missouri, Columbia, MO).

Sow and Litter Performance

All sows were weighed and backfat depth was determined at breeding and at the start and the end of all 3 phases of gestation and lactation. Backfat measurements were taken ultrasonically (Lean-Meater, Renco Corp., Minneapolis, MN) at the last rib about 6.5 cm from both side of the backbone using cooking oil as coupling fluid. The value from both left and right sides were averaged to obtain backfat depth. Feed allowed and wasted was also recorded on daily basis during lactation.

Litter weight was taken at birth and at the end of each phase until weaning. Total piglets born, born alive, mummies, stillborn, number and weight of the piglets cross fostered were also recorded. Incidence of death, probable cause and the weight of the dead piglets were also recorded. After weaning sows were monitored daily for post-weaning estrus and the dates were recorded to determine wean to estrus interval.

Blood sampling and AA analysis

Blood samples were collected from 8 sows per treatment via jugular venipuncture 4 hour post feeding in BD vacutainer (Becton, Dickinson and Company, NJ) without anticoagulant at breeding and d 109 of gestation and at d 6 of lactation and at weaning. Blood samples were centrifuged at 1500 × g for 15 minutes and serum samples were stored at -80°C for later analysis. Serum samples were analyzed for concentration of free AAs and their percentage in total amino acid as described by Wang et al., (2016)

Concentrations of all free AA in serum were determined by liquid chromatography–mass spectrometry (LC-MS) using a modified method based on Márquez et al. (1986). Briefly, serum sample was prepared by mixing one volume of serum, one volume of 100 μM p-chlorol-L-phenylalanine (internal standard), and 18 volumes of 66% aqueous acetonitrile, and then centrifuging at 18,000 × g for 10 min to obtain the supernatant. Five µL of deproteinized sample was mixed with 40 μL of Na2CO3 (10 mM, pH = 11) and 100 μL of dansyl chloride (3 mg/mL in acetone). The mixture was incubated in a water bath at 60° C for 10 min followed by centrifugation at 18,000 × g for 10 min at 4° C. The supernatant was transferred to a HPLC vial and a 5 μL of aliquot was injected into an Acquity ultra-performance liquid chromatography (UPLC) system (Waters, Milford, MA) and separated in a BEH C18 column using a mobile phase gradient ranging from water to 95% aqueous acetonitrile containing 0.1% formic acid over a 10 min run. LC eluent was introduced into a Xevo-G2-S quadrupole time-of-flight mass spectrometer (QTOFMS, Waters) for accurate mass measurement and ion counting. Capillary voltage and cone voltage for electrospray ionization was maintained at 3 kV and 30 V for positive-mode detection. Source temperature and desolvation temperature were set at 120°C and 350°C, respectively. Nitrogen was used as both cone gas (50 L/h) and desolvation gas (600 L/h), and argon as collision gas. For accurate mass measurement, the mass spectrometer was calibrated with sodium formate solution (range m/z 50-1,000) and monitored by the intermittent injection of the lock mass leucine enkephalin ([M+H]+ = m/z 556.2771) in real time. Mass chromatograms and mass spectral data were acquired and processed by MassLynxTM software (Waters) in centroided format. Individual AA concentrations were determined by calculating the ratio between the peak area of AA and the peak area of internal standard and fitting with a standard curve using QuanLynxTM software (Waters).

Statistical Analysis

All the data were analyzed by SAS 9.4. Variables related to number of piglets, stillborn, mummy, and wean to estrus interval were considered as count data and analyzed by the GLIMMIXD procedure, and the remaining variables measured were considered as continuous variables and analyzed by the MIXED procedure. Number ofpiglets born alive,bornintotal,stillborn, and mummies for the current parity were analyzed as completely randomized block design with block (batch) as random effect and gestation treatment and parity as fixed effects with Poisson distribution. The remaining count data from the current parity and all count data in the subsequent parity were analyzed as split-plot design (main plot gestation and subplot lactation) with block (batch) as random effect and gestation, lactation, the interaction between gestation and lactation, and parity as fixed effects with Poisson distribution. Attempt was made to account for over dispersion by inclusion of the second random statement (random _residual_).

Sow body weight and backfat depth on days 35, 70 and 109 of gestation for the current parity were analyzed as completely randomized block design with repeated measures, whereas sow body weight, backfat depth, litter weight on days 6 and 12 and at weaning of lactation for the current parity, and sow feed intake during the 3 phases of lactation for both the current and subsequent parity were analyzed as split-plot design (main plot gestation and subplot lactation) with repeated measures. Sow body weight and backfat at breeding and their changes during gestation of the current parity were analyzed as completely randomized block design with block (batch) as random effect and gestation treatment and parity as fixed effects. The remaining continuous variables were analyzed as split-plot design (main plot gestation and subplot lactation) with block (batch) as random effect and gestation, lactation, the interaction between gestation and lactation, and parity as fixed effects. Means were separated by PDIFF option. A significant level was set at 0.05 and trend was considered if p-value between 0.05 and 0.1. Least square means and standard errors are presented