Graded supplemental choline chloride fed throughout the grow and finish periods elicited minimal influence on growth performance and carcass characteristics of pigs in a commercial setting

Abstract

Choline is vital in a variety of physiological processes that influence brain development, growth, and carcass characteristics in birds and mammals. In this study, we investigated the influence of graded supplemental choline chloride on growth performance, carcass quality, and liver characteristics in grow-finish pigs. Pigs (672 barrows and 588 gilts) were obtained from a commercial nursery facility at 8 weeks of age and assigned to treatment based on body weight and sex, with 21 same-sex pigs comprising a replicate pen. Each dietary treatment was provided to 15 replicate pens, with 8 pens of barrows and 7 pens of gilts per each of 4 dietary treatments, which included: 1) C0, basal diet containing 0% of supplemental choline chloride; 2) C300, C0 + 0.06% supplemental choline chloride, to provide 300 mg/kg of choline ions; 3) C600, C0 + 0.12% supplemental choline chloride, to provide 600 mg/kg of choline ions; and 4) C900, C0 + 0.17% supplemental choline chloride, to provide 900 mg/kg of choline ions. Feed and water were provided ad libitum throughout the study, and pigs were managed using standard commercial practices. Data were analyzed by two-way ANOVA using the MIXED procedure of SAS, with factors including dietary treatment and sex. There was no dietary impact (P > 0.05) on growth performance. Pigs receiving intermediate levels of supplemental choline had higher (P < 0.05) tenderloin weights compared with other dietary treatments. Furthermore, and as expected, sex differences were denoted in both growth performance and carcass characteristics. Overall, graded supplementation of choline chloride did not significantly alter growth performance or carcass characteristics of pigs raised in a commercial setting.

Graded supplemental choline chloride fed throughout the grow and finish periods had no impact on growth performance and elicited minimal influence on carcass characteristics of pigs in a commercial setting.

Introduction

Choline is considered an essential nutrient in pigs as they cannot produce enough of it via de novo synthesis to meet biological requirements. However, pigs are able to obtain dietary choline through choline-enriched feed ingredients (e.g., soybean). Choline, as a pseudo-vitamin, is physiologically essential as it acts as a precursor for the synthesis of phosphatidylcholine and acetylcholine (Jiao et al., 2018; Qiu et al., 2021). Therefore, choline is vital in various metabolic and physiologic processes, including methylation, membrane integrity, neurotransmission, phospholipid synthesis, and lipid metabolism within the liver (Li et al., 2015; Jiao et al., 2018; Gregg et al., 2023; Xie et al., 2023). Furthermore, it significantly influences brain development, growth, and carcass characteristics in both pigs and poultry (Mudd et al., 2016; Mudd et al., 2018; Qiu et al., 2021; Gregg et al., 2023). Due to its role in growth and development, supplemental choline may be included in commercial corn-soybean meal-based swine diets to prevent deficiency (Southern et al., 1986), where grow-finish pigs have an estimated daily requirement of 0.30 g of choline/kg of BW (NRC, 2012).

There is a dearth of studies focused on the ability for supplemental dietary choline to influence growth performance and carcass characteristics of pigs, and variable responses have been reported. Choline chloride supplementation at 1,600 mg/kg of diet in weanling pigs increased BW and feed efficiency (Qiu et al., 2021). In contrast, supplementation of 2,000 mg of choline chloride/kg of diet was reported to reduce daily BW gain in wean-to-finish pigs (Southern et al., 1986). In grow-finish pigs, supplementing choline chloride at 5,000 to 10,000 mg/kg of diet increased carcass weight (Jiao et al., 2018; Xie et al., 2023), marbling, and backfat thickness at market age (Jiao et al., 2018). Given the variable responses and general lack of information regarding the supplementation of choline in grow-finish pigs, our objective was to determine the effects of graded levels of choline chloride supplementation on growth performance, carcass cutability, and meat quality of pigs managed in a commercial setting. We hypothesized that pigs receiving supplemental choline in excess of physiological requirements would exhibit improvements in growth performance and carcass characteristics.

Materials and Methods

Prior to study initiation, all animal care and experimental procedures were approved by the University of Illinois Institutional Animal Care and Use Committee. A total of 1,260 (672 barrows and 588 gilts) pigs were obtained from a commercial nursery facility. At 8 wk of age, 21 same-sex pigs were grouped to form replicate pens, which served as the experimental unit for all growth performance outcomes. Within sex, pigs were stratified by BW with four pens in proximity containing 1 replicate pen per dietary treatment. Each dietary treatment was provided to 15 replicate pens (i.e., seven pens of gilts and eight pens of barrows), with an average starting BW across all pens of 37.19 ± 1.7 kg. The study was completed in 1 cohort with pigs maintained in 60 total pens across three rooms in a single barn. Each pen measured 3.05 m × 4.48 m, thereby providing 0.63 m² of floor space per pig.

Dietary treatments were delivered using an automatic feeding system. Experimental diets were fed in 3 feeding phases: Phase 1, 34 to 68 kg BW; Phase 2, 68 to 91 kg BW; and Phase 3, 91 to 129 kg BW. There were four experimental diets with graded levels of supplemental choline chloride: 1) C0, basal diet containing 0% of supplemental choline chloride; 2) C300, C0 + 0.06% supplemental choline chloride, to provide 300 mg/kg of choline ions; 3) C600, C0 + 0.12% supplemental choline chloride, to provide 600 mg/kg of choline ions; and 4) C900, C0 + 0.17% supplemental choline chloride, to provide 900 mg/kg of choline ions. All diets met or exceeded all nutrient recommendations for grow-finish pigs (NRC, 2012), and ingredient composition and calculated nutrient content of experimental diets can be found in Table 1.

Table 1.

Ingredient and calculated nutrient composition of basal diets (as-fed basis) for grow-finish pigs¹

Item	Phase 1	Phase 2	Phase 3
Ingredient, %
Corn	64.54	73.75	80.02
Corn germ meal	15.00	12.50	8.75
Soybean meal	17.15	10.88	8.43
Choline chloride2	0.00	0.00	0.00
Vitamin premix3	0.03	0.03	0.02
Limestone	1.13	1.50	1.00
Monocalcium phosphate	0.56	0.28	0.03
Sodium chloride	0.50	0.55	0.33
Copper chloride hydroxide	0.03	0.03	0.03
Trace mineral premix4	0.08	0.08	0.06
Fat, yellow grease	0.35	0.35	0.35
DL-Methionine, 99%	0.12	0.06	0.03
L-Threonine, 98%	0.08	0.08	0.07
L-Tryptophan, 98%	0.00	0.01	0.01
L-Lysine HCL, 98%	0.39	0.34	0.31
L-Valine, 96.5%	0.01	0.00	0.00
Phytase5	0.02	0.02	0.02
Calculated Composition
ME, kcal/kg	661.5	671.0	678.6
Crude protein, %	16.52	13.60	12.00
Total amino acids, %
Lys	1.06	0.85	0.74
Met	0.38	0.29	0.24
Trp	0.18	0.16	0.14
Thr	0.69	0.57	0.51
Val	0.73	0.60	0.53
SID amino acids, %
Lys	0.93	0.74	0.64
Met + Cys	0.53	0.42	0.37
Trp	0.16	0.13	0.12
Thr	0.57	0.46	0.41
Val	0.61	0.49	0.43

¹Phase 1 diets were formulated for 34 to 68 kg BW, phase 2 diets for 68 to 91 kg BW, and phase 3 diets for 91 to 129 kg BW. The control choline diet (C0) was blended with the high choline diet (C900) to form diets containing 300 and 600 mg/kg of choline. Each diet across all phases was analyzed for choline concentration resulting in 0, 224, 448, and 671 g/kg of choline in diets C0, C300, C600, and C900, respectively. Abbreviations: ME, metabolizable energy; SID, standardized ileal digestible.

²Choline chloride 70% aqueous included as PuraChol (Balchem; Montvale, NJ).

³Provided per kg of vitamin premix (The Maschhoffs; Carlyle, IL): vitamin A (retinyl acetate), 17,600,000 IU; vitamin D3 (cholecalciferol), 2,750,000 IU; vitamin E (dl- or d-α-tocopheryl acetate), 88,000 IU; vitamin K (menadione dimethylpyrimidinol bisulfite), 5,060 mg; riboflavin, 19,800 mg; vitamin B12 (cyanocobalamin), 77 mg; pantothenic acid (d-calcium pantothenate), 71,500 mg; and niacin (nicotinamide and nicotinic acid), 83,600 mg.

⁴Provided per kg of trace mineral premix (The Maschhoffs; Carlyle, IL): Cu (copper sulfate), 16.5 g; Fe (ferrous sulfate), 165 g; I (Ca iodate, ethylenediamine dihydroiodide), 297 mg; Mn (manganese sulfate, manganese oxide), 38.5 g; Se (sodium selenite), 297 mg; and Zn (zinc oxide), 165 g.

⁵Ronozyme HiPhos 2500 GT (DSM; Heerlen, Netherlands).

Pig BW was measured on a pen basis at the beginning of study and at weeks 11, 15, 18, 20, and 22 of age. Feed distribution was recorded by the automated feeding system and the mass of feed remaining was recorded on the same schedule as pig BW measurements described above to calculate feed disappearance (i.e., intake). Growth performance outcomes included average pen BW, average daily BW gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F; i.e., feed efficiency).

Following the capture of live weights at 18 and 20 wk of age, if the average pen BW was 122.5 ± 3.18 kg, the heaviest 50% of pigs in that pen were selected and slaughtered at a commercial processing facility (JBS, Beardstown, IL). Two weeks after the first cut, the remaining pigs in that pen went to market. Within this second marketing cut from 20 wk of age, 12 pigs per treatment split evenly by sex were selected based on visual appraisal of BW as representative of the pen. These pigs were transported to the University of Illinois Meat Science Laboratory for carcass cutability, meat quality, and liver weight and composition measurements, with all methods further described below. All remaining pigs were slaughtered at the commercial facility. Hot carcass weight (HCW), loin depth, and backfat depth were obtained for all pigs slaughtered at the commercial processing facility.

Slaughter

Pigs were transported to the University of Illinois Meat Science Laboratory (Urbana, IL) and held in lairage for a minimum of 16 h prior to slaughter, during which time they were provided ad libitum access to water, but not feed. Ending live weight (ELW) was recorded prior to humane slaughter. Pigs were immobilized utilizing head-to-heart electrical stunning and then terminated via exsanguination under the supervision of the United States Department of Agriculture Division of Food Safety Inspection Service. After slaughter, but prior to chilling, the liver was extracted and the absolute mass recorded prior to collecting a representative tissue sample for subsequent analysis of lipid concentration. Approximately 45 min postmortem, HCW was recorded, with carcass yield determined by dividing HCW by ELW. Leaf fat was removed prior to the recording of HCW and therefore was not included in the determination of carcass yield.

Carcasses were chilled at 4 °C for a minimum of 20 h, after which time the left side of each carcass was used to determine carcass composition. This side was separated with a hand saw between the 10th and 11th ribs to expose the longissimus thoracis lumbar (LTL). Backfat depth was measured at three-quarters the distance beyond the LTL location dorsal to the vertebral column. Loin muscle area (LMA) was measured by tracing the surface of the LTL onto acetate paper. The LTL tracings were subsequently measured by two independent observers using a digitizer tablet (Wacom, Vancouver, WA) and Adobe Photoshop CS6 (Adobe Systems Inc, San Jose, CA, USA). The average of these two measurements was used to represent LMA.

Carcass fabrication

At approximately 1 d postmortem, the left sides of pork carcasses were fabricated into primal and subprimal cuts. Left sides were weighed and chilled side weight was recorded. Sides were then fabricated to meet specifications described in the North American Meat Institute Buyer’s guide (NAMI, 2014). Chilled were fabricated into pork legs (NAMP #410), skin-on whole loins (NAMP #410), pork shoulder (NAMP #403), neck bones (NAMP #421), jowl (NAMP #419), natural fall belly, skin-on (NAMP #408), and spareribs (NAMP #416). Whole primals were cut to NAMI specifications and weighed before any further fabrication occurred. Skinned and trimmed pork legs were fabricated into a five-piece ham according to Boler et al. (2011). Skin-on loins were separated into anterior and posterior portions. Loins were then skinned and fabricated to meet specification of a bone-in loin (NAMP #410). Skinned anterior and posterior portions were weighed to determine weight of the whole skin off loin. Anterior and posterior portions were then fabricated into Canadian back loin (NAMP #414), tenderloin (NAMP #415A), and sirloin (NAMP #413D). Whole shoulders were skinned and fabricated to meet the standard for a skinned pork shoulder (NAMP #404). Skinned shoulders were further fabricated to meet the specifications for bone-in Boston butt (NAMP #406) and bone-in picnic (NAMP #405). Bones were removed from bone-in shoulders and picnics to produce boneless Boston butt (NAMP #406A) and boneless picnic (NAMP #405A). Natural fall bellies and Canadian back loins were retained for later quality evaluation. Carcass cutting yields were determined utilizing the following equations:

$${\displaystyle \begin{array}{l}{\displaystyle \begin{array}{lllll}& {\displaystyle Bone\text{-}inleancuttingyield,\mathrm{\%}=[(trimmedham\left(NAMP\mathrm{\#}402\right),}& {\displaystyle kg+bone\text{-}intrimmedBostonbutt\left(NAMP\mathrm{\#}406\right),}& {\displaystyle kg+bone\text{-}inpicnic\left(NAMP\mathrm{\#}405\right),kg+trimmedloin}& {\displaystyle (NAMP\mathrm{\#}410),kg)/chilledleftsideweight,kg]\times 100}\end{array}}\end{array}}$$

$${\displaystyle \begin{array}{l}{\displaystyle \begin{array}{llll}& {\displaystyle Bone\text{-}incarcasscuttingyield,\mathrm{\%}=[(bone\text{-}inleancuttingyield}& {\displaystyle components+naturalfallbelly\left(NAMP\mathrm{\#}408\right),kg+spareribs}& {\displaystyle \left(NAMP\mathrm{\#}416\right))/chilledleftsideweight,kg]\times 100}\end{array}}\end{array}}$$

$${\displaystyle \begin{array}{l}{\displaystyle \begin{array}{llllllll}& {\displaystyle Bonelesscarcasscuttingyield,\mathrm{\%}=[(insideham\left(NAMP\mathrm{\#}402F\right),}& {\displaystyle kg+outsideham\left(NAMP\mathrm{\#}402E\right),kg+knuckle\left(NAMP\mathrm{\#}402H\right),kg]}& {\displaystyle +innershank,kg+litebutt,kg+Canadianback\left(NAMP\mathrm{\#}414\right),}& {\displaystyle kg+tenderloin\left(NAMP\mathrm{\#}415A\right),kg+sirloin(NAMP\mathrm{\#}413D),kg)}& {\displaystyle +bonelessBostonbutt\left(NAMP\mathrm{\#}406A\right),kg+bonelesspicnic}& {\displaystyle (NAMP\mathrm{\#}405A),kg+naturalfallbelly\left(NAMP\mathrm{\#}408\right),kg)}& {\displaystyle +spareribs\left(NAMP\mathrm{\#}416\right))/chilledleftsideweight]\times 100}\end{array}}\end{array}}$$

Early postmortem loin quality evaluation

Loin quality measurements were taken by trained University of Illinois personnel for ultimate pH, visual marbling, visual color, subjective firmness, and instrumental color at 1 d postmortem. The ventral surface of the boneless loin was evaluated at approximately the 10th rib. Loins were allowed to oxygenate for 20 min prior to taking measurements. Ultimate pH was measured with a portable pH meter (Hanna Instruments, Woonsocket, RI, USA) calibrated to a pH of 4 and 7 with buffers at 4 °C with an appropriate electrode (Hanna 4198163 pH meter, −2.0 to 20.0 pH/±2000.0 mV; Hanna FC2323 meat specific electrode; 2-point calibration; pH 4 and pH 7). Instrumental color, lightness (L*), redness (a*), and yellowness (b*), were measured with a colorimeter (CR-400 Chroma Meter; Konica Minolta Sensing Americas Inc., Ramsey, NJ, USA). A single trained technician recorded visual color, marbling (NPPC, 1999), and subjective firmness (NPPC, 1991) for all loins.

Canadian back loins were faced at approximately the 10th rib to produce a chop weighing approximately 50 g to be used for drip loss measurements. Loins were sliced into approximately 2.54 cm thick chops. The anterior-most chops were used for quality evaluation including instrumental color, visual color, visual marbling, and subjective firmness. After quality measurements were recorded, chops were vacuum packaged and utilized for cook loss and Warner-Bratzler (WB) shear force evaluation at a later time. Chops retained for cook loss and WB shear force measurements were held at −20 °C until measurements were taken. Drip chops were weighed, suspended by hooks in plastic bags (Whirl-Pak; Nasco Sampling, Madison, WI, USA), and stored at 4 °C. After 24 h, the chops were reweighed, and drip loss was recorded as weight lost as a percentage of initial weight.

Belly quality evaluation

Fresh bellies were evaluated for length, width, flop, and thickness at 4 d postmortem. Bellies were measured from anterior-to-posterior midline for length, and from dorsal-to-ventral midline for width. Thickness was determined using the average of eight points on the belly that represented 20, 40, 60, and 80% of the length of the belly on both dorsal and ventral sides. Flop was determined by placing the belly skin down over a metal bar and measuring the distance between anterior and posterior ends of the belly.

Cook loss and WB shear force

Chops were allowed to thaw at 4 °C for at least 24 h before being weighed individually and then cooked. Chops were cooked on Farberware Open Hearth grills (model 455N, Walter Kidde, Bronx, NY, USA). Internal temperature of chops was monitored using thermocouples (type K, 121 range: −200 °C to 1,250 °C, standard error: ± 2.2 °C, Omega Engineering, Stanford, CT, USA) that were placed in the geometric center of chops and attached to a data logger thermometer (Omega HH378, Omega Engineering, Norwalk, CT). Prior to grilling, the initial weight was recorded for later calculation of cook loss. When the internal temperature reached 31 °C samples were flipped and cooked to an internal temperature of 63 °C. Once removed, thermocouples remained in chops until a maximum internal temperature was recorded. The chops were allowed to rest and reach room temperature (25 °C), then final chop weights were recorded to calculate cook loss percentage. Four 1.25-cm diameter core samples were taken parallel to the muscle fiber orientation and sheared using a Texture Analyzer TA. HD Plus (Texture Technologies Corp., Scarsdale, NY/Stable Micro Systems, Godalming, UK) with a blade speed of 3.33 mm/s and load cell capacity of 100 kg. Shear force values for four samples were averaged and reported as WB shear force values. Cook loss percentage was calculated by utilizing the following equation:

$${\displaystyle \begin{array}{lll}{\displaystyle Cookloss,\mathrm{\%}=}& [(initialweight,g-finalweight,g)& ÷initialweight,g]\times 100\end{array}}$$

Liver weight and lipid composition

During slaughter at the University of Illinois Champaign-Urbana Meat Science Laboratory, final live BW and whole liver weights were recorded to analyze absolute and relative measurements. Representative liver tissue subsamples were then collected for subsequent analyses. Dry matter (DM) was determined in duplicate after drying samples in a 105 °C oven for a minimum of 48 h (method 934.01, AOAC, 2002). Lipid content of liver samples was determined in duplicate using a diethyl ether solution (method 960.39, AOAC, 2002).

Statistical analysis

Pen served as the experimental unit for growth performance and carcass outcomes from the commercial processing facility, while individual pig served as the experimental unit for all outcomes performed at the University of Illinois Urbana-Champaign. Data were corrected for mortality, and room was utilized as a random variable. All data were subjected to an analysis of variance (ANOVA) using the MIXED procedure of SAS (version 9.4; SAS Institute, Cary, NC). A two-way ANOVA was used to determine whether the main and interaction effects of dietary treatment and sex were significant. However, due to the limited significance of interaction effects, they are provided only in the Supplementary Tables S1–S9. For individual diet and sex effects, mean separation was conducted assuming an alpha level of 0.05. Diet and sex P-values were reported along with pooled SEM estimates for each outcome. Outliers were identified as having an absolute Studentized residual value of 3 or greater and were removed prior to the final statistical analysis.

Results and Discussion

Choline is an essential nutrient for pigs due to limited endogenous synthesis, with most obtained from the diet (Southern et al., 1986; Zeisel, 1992; Sherriff et al., 2016). After absorption in the small intestine, choline may be transported to the liver, where it undergoes oxidation, acetylation, or phosphorylation. These processes support key functions such as transmethylation of homocysteine to methionine, acetylcholine production, and phospholipid synthesis (Zeisel, 1981; Zeisel, 1992; Xie et al., 2023). As a result, choline plays a significant role in various physiological processes influencing growth, body composition, carcass characteristics, and even brain development in pigs (Mudd et al., 2016; Jiao et al., 2018; Mudd et al., 2018; Qiu et al., 2021).

Largely due to the availability of choline-related compounds in soybean products, the NRC (2012) consensus report indicates that pigs receiving corn-SBM diets do not benefit from choline supplementation. However, Qiu et al. (2021) and Xie et al. (2023) reported that supplementing choline levels beyond NRC (2012) recommendations positively affected growth performance and enhanced carcass characteristics, respectively. Beyond these reports, research on choline’s impact on swine is limited and there is a need for further research to assess the impact of choline chloride supplementation on carcass characteristics and meat quality. In this study, we evaluated the effect of graded levels of choline chloride supplementation in grow-finish pigs on growth performance, carcass cutability, fresh loin and belly quality, and liver characteristics.

Growth performance

Given that the first cut of pigs was sent for slaughter following the capture of growth performance data during weeks 18 to 20 of age, caution should be exercised when interpreting statistical effects thereafter as experimental units were inextricably changed (i.e., pig densities and social interactions within pen would have been influenced). Effects of diet and sex on growth performance are displayed in Table 2. Counter to our hypothesis, supplemental choline did not influence growth performance at any inclusion rate throughout the entirety of the study. These results differ from Qiu et al. (2021) who reported that supplementation of 1,600 mg of choline from 21 d to 49 d of age increased final BW, ADG, and G:F. The differences between the current study and the latter may be a result of differences in the age and physiological status of pigs and the duration choline was supplemented. For instance, Qiu et al. (2021) supplemented choline immediately after weaning when pigs were undergoing a variety of psychological and physiological stressors.

Table 2.

Effects of sex and dietary treatment on growth performance of grow-finish pigs¹

Outcome	Dietary treatment						Sex
	C0	C300	C600	C900	SEM	P-value	Barrows	Gilts	SEM	P-value
Pens, n	15	15	15	15	–	–	32	28	–	–
Body weight, kg
Starting	36.26	36.31	36.29	36.27	1.598	1.00	35.12b	37.45a	1.589	<0.001
Week of age 11	59.95	59.39	59.47	59.28	3.163	0.69	58.86b	60.17a	3.152	0.01
Week of age 15	92.46	91.92	91.84	91.52	3.829	0.71	92.14	91.74	3.872	0.55
Week of age 18	117.12	115.99	116.66	116.03	3.756	0.71	116.51	116.39	3.723	0.90
Week of age 20	124.86	124.20	125.05	125.10	2.404	0.71	125.44	124.16	2.372	0.08
Week of age 22	129.61	126.66	126.55	126.99	1.507	0.14	129.22a	125.69b	1.372	0.002
Week of age 8 to 10
ADG, kg/d	1.04	1.01	1.02	1.01	0.029	0.21	1.04a	1.00b	0.028	0.002
ADFI, kg/d	2.23	2.19	2.18	2.15	0.097	0.09	2.19	2.18	0.096	0.76
G:F	0.47	0.46	0.47	0.47	0.008	0.71	0.47b	0.45a	0.008	<0.001
Week of age 11 to 14
ADG, kg/d	1.20	1.20	1.20	1.20	0.022	0.99	1.24a	1.17b	0.021	<0.001
ADFI, kg/d	3.02	3.03	3.00	2.98	0.120	0.73	3.12a	2.89b	0.119	<0.001
G:F	0.40	0.40	0.40	0.40	0.008	0.94	0.40b	0.41a	0.008	0.002
Week of age 15 to 17
ADG, kg/d	1.16	1.15	1.16	1.15	0.021	0.98	1.14	1.18	0.016	0.07
ADFI, kg/d	3.33	3.29	3.36	3.34	0.04	0.44	3.44a	3.22b	0.033	<0.001
G:F	0.35	0.35	0.35	0.35	0.004	0.77	0.33b	0.37a	0.003	<0.001
Week of age 18 to 19
ADG, kg/d	0.87	0.94	1.00	0.95	0.085	0.60	1.06a	0.81b	0.074	0.001
ADFI, kg/d	3.17	3.20	3.40	3.24	0.102	0.08	3.48a	3.02b	0.093	<0.001
G:F	0.26	0.29	0.29	0.29	0.023	0.68	0.30	0.26	0.019	0.05
Week of age 20 to 222
ADG, kg/d	0.83	0.81	0.82	0.75	0.261	0.62	0.88a	0.75b	0.259	0.031
ADFI, kg/d	3.50	3.47	3.45	3.38	0.092	0.84	3.65a	3.25b	0.068	<0.001
G:F	0.30	0.29	0.29	0.28	0.008	0.51	0.29	0.29	0.006	0.68

¹Values are least-square means derived from 15 replicate pens for dietary treatments. Pens contained 21 of the same-sex pigs from week 8 until the first round of market cuts at week 18, at which point half of the pen was shipped after weighing to a commercial processing plant in Beardstown, IL. 14 d post first cut; the second cut of pigs were shipped for processing. The data in this table is representative of both cuts, however, cut 2 data is missing for 1 replicate of C300, and 2 replicates for treatments C600 and C900. Abbreviations: ADG, average daily body weight gain; ADFI, average daily feed intake; BW, body weight; G:F, gain-to-feed ratio or feed efficiency.

²Included only the second cut of pigs, so caution should be exercised when interpreting these results due to uncontrolled changes to the experimental unit at this time-point.

^{a , b}Means lacking a common superscript letter within a row differ (P < 0.05).

An effect of sex was observed as barrows had heavier (P < 0.05) BW, higher ADG and ADFI, and lower G:F when compared with gilts. These findings align with those of Latorre et al. (2004), who similarly reported that sex influenced growth performance, with barrows exhibiting higher ADFI and ADG than gilts. Furthermore, in the current study gilts demonstrated superior G:F compared with barrows, which further reinforces the impact of sex on growth performance reported by Latorre et al. (2004).

Carcass characteristics

Diet and sex effects for carcass characteristics from the commercial facility are displayed in Table 3. No main effect of dietary treatment was observed for any carcass characteristics. These results contradict with those reported by Xie et al. (2023), who reported that choline chloride supplementation beyond the estimated physiological requirement resulted in increased carcass weight and a reduction in dressing percentage. The discrepancy between the current study and the latter again may stem from duration of choline supplementation. In the current study, choline was supplemented throughout the entire grow-finish period, whereas Xie et al. (2023) only provided supplemental choline for 14 d during finishing. Additionally, no diet-related changes in backfat were observed in the current study, aligning with the results of both Xie et al. (2023) and Jiao et al. (2018), which reported that supplemental choline had no impact on backfat thickness in finishing pigs or nursery pigs, respectively. As anticipated, an effect of sex was observed as barrows had increased (P < 0.05) ELW and 10th rib backfat compared with gilts but had reduced muscle depth and lean percent than gilts. These results are congruent to Latorre et al. (2004) which reported sex differences in pigs at slaughter with barrows having increased final weight and backfat compared with gilts.

Table 3.

Effects of sex and dietary treatment on carcass characteristics from a commercial processing facility¹

Outcome	Dietary treatment						Sex
	C0	C300	C600	C900	SEM	P-value	Barrows	Gilts	SEM	P-value
Pens, n	15	15	15	15	–	–	32	28	–	–
Ending live weight, kg	129.62	128.41	129.31	126.35	0.527	0.41	130.08a	128.26b	0.385	0.001
Hot carcass weight, kg	97.10	96.29	97.08	97.09	0.534	0.60	97.37	96.41	0.385	0.07
Carcass yield, %	75.03	75.15	75.30	74.97	0.268	0.56	74.83b	75.34a	0.242	0.024
10th rib backfat, cm	27.80	21.24	21.72	21.50	0.480	0.51	22.96a	20.16b	0.444	<0.001
Muscle depth, cm	66.57	66.27	67.25	67.32	0.889	0.45	66.13b	67.57a	0.810	0.020
Lean percent, %	52.93	53.13	53.09	53.16	0.357	0.55	52.48b	53.67a	0.347	<0.001

¹Values are least-square means derived from 15 replicate pens for dietary treatments. Pens contained 21 of the same-sex pigs from week 8 until the first round of market cuts at week 20, at which point half of the pen was shipped to a commercial processing plant in Beardstown, IL. The second cut of pigs was shipped for processing 14-d after the first cut. The data in this table is representative of both cuts, however, cut 2 data is missing for 1 replicate of C300 and 2 replicates for treatments C600 and C900.

^{a ,}

^bMeans lacking a common superscript letter differ (P < 0.05) within a row.

Loin and belly quality

Carcass characteristics and loin and belly quality are displayed in Table 4. There was no effect of diet on carcass characteristics or loin and belly quality. Similar results were observed by Jiao et al. (2018), when supplemental choline chloride had no impact on meat color, sensory evaluation (i.e., color, firmness, and cook loss), or drip loss. However, there was an effect of sex with barrows having increased (P < 0.05) cook loss and belly flop when compared with gilts. These results differ from the effect of sex reported by Latorre et al (2004), which observed that cooking loss was higher in barrows than gilts. Differences in statistical inferences between these studies may be the result of statistical power due to varying numbers of replicated experimental units.

Table 4.

Effects of sex and dietary treatment on carcass characteristics and loin and belly quality in pigs fed graded levels of choline¹

Outcome	Dietary treatment						Sex
	C0	C300	C600	C900	SEM	P-value	Barrows	Gilts	SEM	P-value
Pigs, n	12	12	12	12	–	–	24	24	–	–
Loin quality
pH	5.59	5.62	5.61	5.61	0.030	0.89	5.61	5.59	0.021	0.49
NPPC color2	3.21	3.58	3.50	3.42	0.187	0.53	3.48	3.38	0.132	0.58
NPPC marbling2	2.33	2.24	2.58	2.23	0.438	0.77	2.55	2.29	0.407	0.41
NPPC firmness2	3.00	3.25	3.17	3.00	0.161	0.62	3.21	3.00	0.114	0.20
Lightness, L*3	48.66	46.91	48.28	48.59	1.058	0.60	48.57	47.64	0.777	0.38
Redness, a*3	8.34	8.11	8.04	8.70	0.462	0.97	8.09	8.20	0.319	0.81
Yellowness, b*3	4.49	3.80	4.07	4.18	0.426	0.69	4.21	2.06	0.294	0.73
Drip loss, %4	4.66	4.25	3.85	3.89	0.477	0.29	4.33	3.75	0.337	0.23
WB shear force, kg5	3.14	2.94	3.24	3.04	0.129	0.40	2.99	3.19	0.091	0.12
Cook loss, %6	19.04	19.21	20.70	21.43	1.467	0.16	21.38a	18.81b	1.366	0.02
Belly quality
Belly length, cm	67.76	69.00	69.32	68.03	0.672	0.31	68.91	68.15	0.476	0.26
Belly width, cm	25.48	26.36	26.09	25.35	0.532	0.49	25.40	26.24	0.377	0.13
Belly flop, cm	25.09	18.79	22.68	19.11	2.434	0.22	25.11a	17.72b	1.721	0.004
Belly thickness7, cm	1.66	1.61	1.55	1.65	0.106	0.45	1.68	1.56	0.101	0.07

¹Values are least-square mean derived from 12 pigs per treatment, 1 pig from 12 of the 15 replicates per dietary treatment. At week of age 22, 48 pigs were shipped to the Meat Science Laboratory at the University of Illinois Urbana-Champaign. The ELWs at MSL differ from the ELWs of pig sent to the commercial processing plant in Beardstown, IL.

²NPPC color and marbling based on the 1999 standards measured in half point increments where 1 = palest, 6 = darkest and where 1 = least amount of marbling, 6 = most amount of marbling. NPPC firmness based on the 1991 scale measured in whole point increments where 1 = softest, 5 = firmest.

³L* measures darkness (0) to lightness (100; greater L* indicates a lighter color), a* measures redness (greater a* indicates a redder color), b* measures yellowness (greater b* indicates a more yellow color).

⁴Drip loss, % = ((initial weight, g.)/(final weight., g)) × 100.

⁵Includes WB shear force evaluation on chops cooked to 63 °C.

⁶Cook loss = [(initial weight, kg – cooked weight, kg) ÷ initial weight, kg] × 100.

⁷Average of eight individual thickness measurements on fresh belly.

^{a , b}Means lacking a common superscript letter differ (P < 0.05) within a row.

Carcass cutability

Maximizing the use and sale of parts of the pig carcass is essential for ensuring the highest economic returns for producers. Breaking down each carcass into both whole and primal cuts enables researchers to assess where growth is occurring or where improvements could be made to increase the amount of salable product. However, there is limited research not only on the effects of diet, but also on how sex influences individual primal cuts in the pork industry.

Diet and sex effects for primal cuts involving whole and trimmed parts (Table 5), ham (Table 6), shoulder (Table 7), and loin (Table 8), along with overall carcass cutability outcomes (Table 9), were largely nonsignificant. The only observed dietary effect involved pigs in the C300 and C600 treatment groups exhibiting increased (P < 0.05) tenderloin weights compared with those in the C900 treatment, whereas C0 pigs were intermediate. Dietary choline supplementation was not shown to alter any other carcass cutability outcomes in this study, which lends credence to past reports with similar findings.

Table 5.

Effects of sex and dietary treatment on whole and trimmed primal cuts¹

Outcome	Dietary treatment						Sex
	C0	C300	C600	C900	SEM	P-value	Barrows	Gilts	SEM	P-value
Pigs n	12	12	12	12	–	–	24	24	–	–
Chilled side wt, kg2	50.43	52.23	52.68	50.54	1.575	0.31	51.44	51.49	1.434	0.97
Whole shoulder, kg	10.86	11.06	11.28	10.72	0.321	0.46	11.07	10.88	0.273	0.52
% chilled side wt	21.51	21.15	21.41	21.20	0.284	0.78	21.43	21.21	0.201	0.43
Bone-in Boston, kg	3.80	3.78	3.93	3.60	0.111	0.24	3.87	3.68	0.079	0.09
% chilled side wt	7.51	7.21	7.43	7.10	0.156	0.23	7.43	7.20	0.110	0.14
Bone-in picnic, kg	5.04	5.23	5.18	5.15	0.163	0.84	5.13	5.16	0.109	0.83
% chilled side wt	10.01	9.97	9.81	10.17	0.228	0.67	9.86	10.12	0.153	0.21
Whole loin, kg	12.80	13.18	13.76	12.67	0.587	0.32	13.08	13.22	0.531	0.77
% chilled side wt	25.42	25.34	25.63	25.48	0.424	0.96	25.59	25.34	0.301	0.55
Trimmed loin, kg	10.66	11.10	11.08	10.80	0.274	0.61	10.82	11.00	0.194	0.51
% chilled side wt	21.05	21.23	20.95	21.28	0.238	0.74	20.74b	21.52a	0.168	0.002
Whole ham, kg	11.54	12.10	12.23	11.82	0.271	0.30	11.78	12.06	0.192	0.30
% chilled side wt	22.78	23.05	23.12	23.31	0.303	0.54	22.64b	23.49a	0.253	0.005
Trimmed ham, kg	10.00	10.53	10.53	10.23	0.254	0.36	10.16	10.49	0.175	0.19
% chilled side wt	19.75	20.07	20.08	20.19	0.401	0.71	19.62b	20.43a	0.353	0.018
Natural fall belly, kg	6.77	7.38	7.14	6.79	0.214	0.15	7.19	6.85	0.151	0.12
% chilled side wt	13.38	14.07	13.50	13.38	0.250	0.17	13.79	13.37	0.177	0.10
Spareribs, kg	1.93	2.04	2.07	1.90	0.061	0.14	1.99	1.99	0.043	0.88
% chilled side wt	3.80	3.90	3.93	3.76	0.096	0.56	3.81	3.89	0.068	0.40

¹Values are least-square mean derived from 12 pigs per treatment, 1 pig from 12 of the 15 replicates per dietary treatment. At week of age 22, 48 pigs were shipped to the Meat Science Laboratory at the University of Illinois Urbana-Champaign.

²Chilled side weight is from the left side and excludes leaf fat and standardized trim.

^{a ,}

^bMeans lacking a common superscript letter differ (P < 0.05) within a row.

Table 6.

Effects of sex and dietary treatment on ham primal cuts¹

Outcome	Dietary treatment						Sex
	C0	C300	C600	C900	SEM	P-value	Barrows	Gilts	SEM	P-value
Pigs, n	12	12	12	12	–	–	24	24	–	–
Inside ham, kg	1.86	2.01	2.05	1.95	0.060	0.12	1.91	2.02	0.048	0.07
% chilled side wt	3.69	3.84	3.87	3.84	0.079	0.33	3.68b	3.94a	0.060	0.002
Outside ham, kg	2.84	2.89	3.03	2.88	0.088	0.48	2.85	2.97	0.062	0.20
% chilled side wt	5.61	5.52	5.72	5.69	0.131	0.69	5.47b	5.81a	0.092	0.013
Knuckle, kg	1.37	1.48	1.44	1.43	0.052	0.56	1.40	1.45	0.037	0.34
% chilled side wt	2.71	2.82	2.73	2.82	0.11	0.61	2.73	2.80	0.099	0.44
Inner shank, kg	0.69	0.75	0.72	0.72	0.023	0.46	0.69b	0.75a	0.016	0.024
% chilled side wt	1.38	1.43	1.36	1.42	0.042	0.43	1.34b	1.45a	0.036	0.005
Lite butt, kg	0.41	0.42	0.46	0.44	0.036	0.43	0.42	0.45	0.032	0.38
% chilled side wt	0.81	0.81	0.88	0.87	0.073	0.63	0.82	0.87	0.066	0.42
Boneless ham, kg2	6.07	6.38	6.50	6.25	0.166	0.30	6.17	6.43	0.117	0.12
% chilled side wt	11.99	12.17	12.31	12.34	0.202	0.60	11.83b	12.58a	0.143	<0.001

¹Values are least-square mean derived from 12 pigs per treatment, 1 pig from 12 of the 15 replicates per dietary treatment. At week of age 22, 48 pigs were shipped to the Meat Science Laboratory at the University of Illinois Urbana-Champaign.

²Boneless ham = inside ham (NAMP #402F), kg + outside ham (NAMP #402E), kg + knuckle (NAMP #402H), kg.

^{a ,}

^bMeans lacking a common superscript letter differ (P < 0.05) within a row.

Table 7.

Effects of sex and dietary treatment on shoulder primal cuts¹

Outcome	Dietary treatment						Sex
	C0	C300	C600	C900	SEM	P-value	Barrows	Gilts	SEM	P-value
Pigs, n	12	12	12	12	–	–	24	24	–	–
Boneless Boston, kg	3.47	3.43	3.55	3.31	0.102	0.41	3.52	3.36	0.072	0.14
% chilled side wt	6.86	6.54	6.72	6.52	0.139	0.28	6.75	6.58	0.099	0.23
Boneless picnic, kg	3.79	3.86	3.88	3.86	0.119	0.95	3.84	3.85	0.084	0.90
% chilled side wt	7.49	7.35	7.34	7.63	0.161	0.55	7.38	7.53	0.114	0.34
Neckbones, kg	1.10	1.22	1.21	1.13	0.053	0.37	1.16	1.17	0.037	0.78
% chilled side wt	2.19	2.33	2.29	2.24	0.101	0.79	2.22	2.30	0.072	0.45
Jowl, kg	1.14	1.22	1.24	1.17	0.067	0.69	1.26a	1.12b	0.048	0.040
% chilled side wt	2.24	2.30	2.33	2.29	0.124	0.95	2.43a	2.16b	0.097	0.038
Clear plate, kg	0.89	0.83	0.96	0.83	0.112	0.16	0.91	0.85	0.109	0.27
% chilled side wt	1.77	1.60	1.83	1.65	0.168	0.16	1.79	1.64	0.161	0.13
Boneless shoulder, kg2	7.26	7.29	7.43	7.17	0.189	0.82	7.36	7.22	0.134	0.47
% chilled side wt	14.35	13.89	14.06	14.15	0.206	0.47	14.12	14.11	0.146	0.94

¹Values are least-square mean derived from 12 pigs per treatment, 1 pig from 12 of the 15 replicates per dietary treatment. At week of age 22, 48 pigs were shipped to the Meat Science Laboratory at the University of Illinois Urbana-Champaign.

²Boneless shoulder = boneless Boston butt (NAMP #406A), kg + boneless picnic (NAMP #405A), kg.

^{a , b}Means lacking a common superscript letter differ (P < 0.05) within a row.

Table 8.

Effects of sex and dietary treatment on loin primal cuts¹

Outcome	Dietary treatment						Sex
	C0	C300	C600	C900	SEM	P-value	Barrows	Gilts	SEM	P-value
Pigs, n	12	12	12	12	–	–	24	24	–	–
Canadian back, kg	3.68	3.77	3.73	3.65	0.108	0.85	3.52b	3.90a	0.076	0.001
% chilled side wt	7.28	7.23	7.05	7.20	0.165	0.78	6.75b	7.63a	0.116	<0.001
Tenderloin, kg	0.49ab	0.51a	0.52a	0.46b	0.016	0.045	0.49	0.50	0.011	0.59
% chilled side wt	0.98	0.99	1.00	0.92	0.052	0.14	0.97	0.97	0.047	0.85
Sirloin, kg	0.67	0.79	0.71	0.73	0.045	0.19	0.74	0.72	0.038	0.69
% chilled side wt	1.34	1.52	1.37	1.45	0.084	0.15	1.43	1.42	0.075	0.91
Backribs, kg	0.89	0.94	1.00	0.93	0.047	0.31	0.94	0.94	0.040	0.90
% chilled side wt	1.76	1.82	1.88	1.84	0.073	0.62	1.83	1.82	0.057	0.96
Backbone, kg	2.10	2.11	2.15	2.09	0.085	0.96	2.12	2.10	0.063	0.81
% chilled side wt	4.14	4.03	4.07	4.12	0.132	0.93	4.07	4.11	0.093	0.78
Boneless loin, kg2	4.83	5.06	4.95	4.82	0.140	0.60	4.74b	5.09a	0.099	0.016
% chilled side wt	9.55	9.69	9.37	9.51	0.202	0.73	9.08b	9.98a	0.143	<0.001

¹Values are least-square mean derived from 12 pigs per treatment, 1 pig from 12 of the 15 replicates per dietary treatment. At week of age 22, 48 pigs were shipped to the Meat Science Laboratory at the University of Illinois Urbana-Champaign.

²Boneless loin = Canadian back loin (NAMP #414), kg + tenderloin (NAMP #415A), kg + sirloin (NAMP #413D), kg.

^a,bMeans lacking a common superscript letter differ (P < 0.05) within a row.

Table 9.

Effects sex and dietary treatment on carcass cutability¹

Outcome	Dietary treatment						Sex
	C0	C300	C600	C900	SEM	P-value	Barrows	Gilts	SEM	P-value
Pigs, n	12	12	12	12	–	–	24	24	–	–
Bone-in carcass cutting yield, %2	71.63	72.57	71.73	72.14	0.493	0.42	71.36b	72.68a	0.367	0.006
Bone-in lean cutting yield, %3	58.37	58.51	58.27	58.77	0.571	0.92	57.53b	59.43a	0.391	0.001
Boneless carcass cutting yield4	51.50	52.09	51.51	51.70	0.433	0.75	50.98b	52.42a	0.308	0.002

¹Values are least-square mean derived from 12 pigs per treatment, 1 pig from 12 of the 15 replicates per dietary treatment. At week of age 22, 48 pigs were shipped to the Meat Science Laboratory at the University of Illinois Urbana-Champaign.

²Bone-in carcass cutting yield = [(trimmed ham, kg + bone-in Boston, kg + bone-in picnic, kg + trimmed loin, kg + natural fall belly, kg) ÷ left side chilled weight, kg] × 100.

³Bone-in lean cutting yield = [(trimmed ham, kg + bone-in Boston, kg + bone-in picnic, kg + trimmed loin, kg) ÷ left side chilled weight, kg] × 100.

⁴Boneless carcass cutting yield = [(inside ham, kg + outside ham, kg + knuckle, kg) + (Canadian back loin, kg + tenderloin, kg + sirloin, kg) + (boneless Boston, kg + boneless picnic, kg) + (belly, kg) ÷ left side chilled weight] × 100.

^{a ,}

^bMeans lacking a common superscript letter differ (P < 0.05) within a row.

Differences in carcass cutability between gilts and barrows were evident, as expected (Lowell et al., 2019). As such, gilts exhibited higher (P < 0.05) percent chilled side weight of the trimmed loin, trimmed ham, whole ham, inside ham, outside ham, inner shank, boneless ham, Canadian back, and backless loin cuts compared with barrows. Conversely, barrows exhibited increased (P < 0.05) chilled side weight of the jowl and clear plate, absolute jowl and clear plate weights, and overall carcass yield when compared with gilts.

Research on the effects of choline on carcass cutability is limited, given the scarcity of information on this topic, and our study aimed to fill that gap. Overall, we observed that excess choline supplementation had no impact on carcass cutability. The absence of choline’s impact on growth and carcass outcomes could be attributed to the pigs being in a stable physiological state, where they are not experiencing rapid growth or immune challenges, which might occur during other stages of development. On the other hand, research has examined the impact of sex on carcass cutability and traits. Studies by Latorre et al. (2003) and Peinado et al. (2008) reported results consistent with the current study regarding whole and trimmed primal cuts. Similarly, Lowell et al. (2019) found comparable sex-related differences in carcass cutability traits, although they observed more sex differences than in the present study, possibly due to higher replication in their research.

Liver analysis

Choline deficiency is known to elicit liver damage and fat accumulation due to an increase in fatty acids, triglyceride synthesis, and de novo lipogenesis (Sheriff et al., 2016). However, a deficiency in choline is not a typical concern in pigs due to their ability to meet most or all their physiological choline requirement through their diet. When provided at adequate levels, choline can act as a precursor for both phosphatidylcholine and acetylcholine in animals, which can prevent fat accumulation within the liver and kidneys, accelerate lipid metabolism, and promote fat transport (Jiao et al., 2018; Qiu et al., 2021; Xie et al., 2023). In the current study neither liver weight nor composition were affected by dietary treatment or sex (Table 10). There is limited literature on the impact of supplemental choline on hepatic lipid accumulation in swine, and most historical research focused on the ability of choline supplementation to prevent hepatic fat accumulation in a deficient context in humans, pigs, and chickens (Zeisel et al., 1991; Zeisel, 1992; Sheriff et al., 2016). Nevertheless, supplementation of dietary choline has been reported to decrease hepatic lipid content in both broiler (Rao et al., 2001) and layer (Schexnailder and Griffith, 1973) chickens. Due to this, the current study was intended to provide more literature on the impact of choline when provided in excess.

Table 10.

Effects of sex and dietary treatment on the liver of grow-finish pigs¹

Outcome	Dietary treatment						Sex
	C0	C300	C600	C900	SEM	P-value	Barrows	Gilts	SEM	P-value
Pigs, n	12	12	12	12	–	–	24	24	–	–
Whole liver weight, kg	1.53	1.64	1.64	1.56	0.044	0.20	1.58	1.60	0.031	0.64
Relative liver weight, %	1.26	1.29	1.29	1.29	0.048	0.87	1.28	1.29	0.046	0.87
Dry matter, %	26.89	26.29	26.73	27.13	0.334	0.21	26.92	26.60	0.279	0.30
Fat, % (dry basis)	7.24	7.47	6.25	5.26	1.046	0.40	6.20	6.91	0.723	0.49
Fat, % (as-is basis)	1.95	1.98	1.69	1.45	0.287	0.50	1.67	1.87	0.198	0.48

¹Values are least-square means derived from 12 pigs per treatment, 1 pig from 12 of the 15 replicates per dietary treatment. At week 22 of age, 48 pigs were shipped to the Meat Science Laboratory at the University of Illinois Urbana-Champaign.

Conclusion

In conclusion, we report herein that supplemental choline fed throughout the grow-finish stage of production in pigs did not alter growth performance or carcass outcomes to any appreciable extent. While choline supplementation did increase absolute weight of the tenderloin, this is not necessarily economically important from a producer perspective. Furthermore, choline supplementation did not impact liver weights or hepatic fat content. Collectively, these results indicate that supplementation of dietary choline chloride in excess of physiological requirements is not advantageous to the growth, carcass characteristics, or hepatic fat content of grow-finish pigs.

Glossary

Abbreviations

ADG

average daily gain

ADFI

average daily feed intake

ANOVA

analysis of variance

BW

body weight

DM

dry matter

G:F

gain-to-feed ratio or feed efficiency

ELW

ending live weight

HCW

hot carcass weight

LTL

longissimus thoracis lumbar

LMA

loin muscle area

NAMI

North American Meat Institute

NAMP

North American Meat Processors Association

NPPC

National Pork Producers Council

UIUC

University of Illinois Urbana-Champaign

WT

weight

Conflict of interest statement

Kari Estes is an employee of Balchem Corporation (Montvale, NJ, USA). No other authors have conflicts of interests to claim.

Author Contributions

Kaitlyn Sommer (Data curation, Formal analysis, Investigation, Methodology, Writing—original draft, Writing—review & editing), Elli Burris (Formal analysis, Investigation, Methodology, Writing—original draft, Writing—review & editing), Julianna Jespersen (Investigation, Writing—review & editing), Kari Estes (Conceptualization, Resources, Writing—review & editing), Anna Dilger (Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing—original draft, Writing—review & editing), and Ryan Dilger (Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing—original draft, Writing—review & editing)