Comparative effects of soy protein concentrate,enzyme‑treated soybean meal,and fermented soybean meal replacing animal protein supplements in feeds on growth performance and intestinal health of nursery pigs

Background Soy protein supplements,with high crude protein and less antinutritional factors,are produced from soybean meal by different processes.This study evaluated the comparative effects of various soy protein supplements replacing animal protein supplements in feeds on the intestinal immune status,intestinal oxidative stress,mucosaassociated microbiota,and growth performance of nursery pigs.Methods Sixty nursery pigs(6.6±0.5 kg BW)were allotted to five treatments in a randomized complete block design with initial BW and sex as blocks.Pigs were fed for 39 d in 3 phases(P1,P2,and P3).Treatments were:Control(CON),basal diet with fish meal 4%,2%,and 1%,poultry meal 10%,8%,and 4%,and blood plasma 4%,2%,and 1%for P1,P2,and P3,respectively;basal diet with soy protein concentrate(SPC),enzyme-treated soybean meal(ESB),fermented soybean meal with Lactobacillus(FSBL),and fermented soybean meal with Bacillus(FSBB),replacing 1/3,2/3,and 3/3 of animal protein supplements for P1,P2,and P3,respectively.Data were analyzed using the MIXED procedure in SAS 9.4.Results The SPC did not affect the BW,ADG,and G:F,whereas it tended to reduce(P=0.094)the ADFI and tended to increase(P=0.091)crypt cell proliferation.The ESM did not affect BW,ADG,ADFI,and G:F,whereas tended to decrease(P=0.098)protein carbonyl in jejunal mucosa.The FSBL decreased(P<0.05)BW and ADG,increased(P<0.05)TNF-α,and Klebsiella and tended to increase MDA(P=0.065)and IgG(P=0.089)in jejunal mucosa.The FSBB tended to increase(P=0.073)TNF-α,increased(P<0.05)Clostridium and decreased(P<0.05)Achromobacter and alpha diversity of microbiota in jejunal mucosa.Conclusions Soy protein concentrate,enzyme-treated soybean meal,and fermented soybean meal with Bacillus could reduce the use of animal protein supplements up to 33%until 7 kg body weight,up to 67%from 7 to 11 kg body weight,and entirely from 11 kg body weight without affecting the intestinal health and the growth performance of nursery pigs.Fermented soybean meal with Lactobacillus,however,increased the immune reaction and oxidative stress in the intestine consequently reducing the growth performance.

Impacts of weaning weights and mycotoxin challenges on jejunal mucosa-associated microbiota,intestinal and systemic health,and growth performance of nursery pigs

Background:This study aimed at investigating the effects of mycotoxin challenge on the growth and physiology of nursery pigs with different weaning weights.Results:At weaning,10 pigs were euthanized to collect jejunal mucosa and 90 pigs were assigned following a randomized complete block design in a 2×2 factorial arrangement of treatments with 3 pigs per pen.Factors were:weaning weight(light:body weight,BW<7.5 kg or heavy:BW>9.0 kg);and dietary mycotoxins(supplementation of 0.2 mg/kg aflatoxins,2.0 mg/kg deoxynivalenol).All diets had titanium dioxide as an external marker at 0.5%.Growth performance and fecal score were recorded until pigs achieved 20 kg BW(light pigs average BW=21.1 kg and heavy pigs average BW=20.5 kg).Pigs were sampled for blood,ileal digesta,jejunal tissue and mucosa at 20 kg BW.Data were analyzed using the mixed procedure of SAS.At weaning,light pigs had decreased(P<0.05)jejunal interleukin-8,increased(P<0.05)tumor necrosis factor-α,and increased(P<0.05)α-diversity indexes of jejunal mucosa-associated microbiota.At 20 kg of BW,light pigs had decreased(P<0.05)average daily gain(ADG),average daily feed intake(ADFI),and gain to feed ratio(G/F).Mycotoxins decreased(P<0.05)BW,ADG,ADFI,and G/F.Light pigs tended to have increased fecal score on d 0(P=0.080),d 10(P=0.069),and increased(P<0.05)fecal score at 20 kg.Mycotoxins decreased the apparent ileal digestibility of nitrogen(P<0.05).Light pigs had increased(P<0.05)intestinal malondialdehydes and interleukin 8.Mycotoxins tended to increase(P=0.060)intestinal tumor necrosis factor-α.Conclusions:Nursery pigs with light weaning weight were more susceptible to jejunal inflammation and had impaired intestinal health due to weaning stress,whereas mycotoxins diminished the health and growth of nursery pigs regardless of weaning weight.

Role of milk carbohydrates in intestinal health of nursery pigs: a review

Intestinal health is essential for the resistance to enteric diseases and for nutrient digestion and absorption to support growth.The intestine of nursery pigs are immature and vulnerable to external challenges,which cause negative impacts on the structure and function of the intestine.Among nutritional interventions,the benefits of milk are significant for the intestinal health of pigs.Milk coproducts have traditionally been used in starter feeds to improve the growth of nursery pigs,but their use is somewhat limited due to the high costs and potential risks of excessive lactose on the intestine.Thus,understanding a proper feeding level of milk carbohydrates is an important start of the feeding strategy.For nursery pigs,lactose is considered a highly digestible energy source compared with plant-based starch,whereas milk oligosaccharides are considered bioactive compounds modulating intestinal immunity and microbiota.Therefore,milk carbohydrates,mainly composed of lactose and oligosaccharides,have essential roles in the intestinal development and functions of nursery pigs.The proper feeding levels of lactose in starter feeds could be variable by weaning age,body weight,or genetic lines.Effects of lactose and milk oligosaccharides have been broadly studied in human health and animal production.Therefore,this review focuses on the mechanisms of lactose and milk oligosaccharides affecting intestinal maturation and functions through modulation of enterocyte proliferation,intestinal immunity,and intestinal microbiota of nursery pigs.

Efficacy of soy protein concentrate replacing animal protein supplements in mucosa-associated microbiota, intestinal health, and growth performance of nursery pigs

This study investigated the effects of using soy protein concentrate (SPC) to replace animal protein supplements on mucosa-associated microbiota,intestinal health,and growth performance of nursery pigs.Fifty-six newly weaned pigs (BW=6.4±0.6 kg) were allotted to 5 treatments in a randomized complete block design.Pigs were fed for 35 d in 3 phases (P;1,2,3) for 10,12,13 d,respectively.Dietary treatments were:(1) basal diet with fish meal (P1:4%,P2:2%,and P3:1%),poultry meal (P1:10%,P2:8%,and P3:4%),and blood plasma (P1:4%,P2:2%,and P3:1%),where SPC replacing none (NC);(2) basal diet with SPC replacing fish meal (RFM);(3) basal diet with SPC replacing poultry meal (RPM);(4) basal diet with SPC replacing blood plasma (RBP);and (5) basal diet with SPC replacing all animal protein supplements (PC).Growth performance was recorded for each phase.Pigs were euthanized on d 35 to collect jejunal mucosa and tissue to evaluate intestinal health and microbiota,and ileal digesta to measure apparent ileal digestibility (AID) of nutrients.Data were analyzed using the MIXED procedure of SAS.Overall,RFM,RPM,and RBP did not affect growth performance,whereas PC decreased (P<0.05) ADG and ADFI.The RPM increased (P<0.05) Prevotella stercorea and decreased (P<0.05) Helicobacter rappini.The PC decreased (P<0.05) H.rappini,whilst increasing (P<0.05) Prevotella copri,Propionibacterium acnes,and Pelomonas aquatica.The RFM tended to increase (P=0.096) immunoglobulin A in the jejunum.The PC tended to decrease (P=0.078) jejunal crypt cell proliferation.There were no differences in the villus height,AID of nutrients,intestinal inflammation,and intestinal oxidative stress among treatments.In conclusion,SPC can replace fish meal,poultry meal,or blood plasma individually without affecting growth performance and intestinal health,and AID of nutrients of nursery pigs.Particularly SPC replacing poultry meal benefitted intestinal health by reducing H.rappini and increasing P.stercorea.However,SPC replacing all three animal protein supplements reduced growth of nursery pigs mainly by reducing feed intake.

Impacts of low level aflatoxin in feed and the use of modified yeast cell wall extract on growth and health of nursery pigs

This study was to investigate the effect of corn naturally contaminated with aflatoxins(AF)under the regulatory level on the growth performance and health of nursery pigs,and the efficiency of yeast cell wall based feed additive(YC)mainly composed ofβ-glucans and mannan oligosaccharide(MOS)(Integral A+,Alltech,Lexington,KY)in prevention of mycotoxicosis.Pigs(60 barrows and 60 gilts at 6.02 ± 0.83kg BW)were randomly allotted to 4 treatments in a randomized complete block design based on a 2×2 factorial arrangement with 10 pens(5 barrow and 5 gilt pens)per treatment and 3 pigs per pen.Pigs were fed experimental diets for 5 wk.First factor was AF(0 or 20 mg/kg in feed)and the second factor was YC(0 or 2 g/kg in feed).Feed intake and body weight were measured weekly,and blood samples were used to measure blood cell counts,immunoglobulin G(Ig G),tumor necrosis factor-a(TNF-a),oxidative damage status,and serological evaluation related to liver health.Aflatoxin decreased(P<0.05)the number of platelet count(247.4 to 193.5×10~3/μL),and it also tended to increase the level of albumin(P=0.055,3.46 to 3.63 g/d L),albumin:globulin ratio(P=0.050,2.09 to 2.37),and Ca(P=0.080,10.79 to 10.97 mg/d L).Yeast cell wall based feed additive increased(P < 0.05)ADG(493 to 524 g/d),and ADFI(796 to 846 g/d)of pigs whereas G:F was not affected,and it also tended to increase(P=0.055)albumin level(3.46 to 3.63 g/d L).Interactions(P < 0.05)on hemoglobin,hematocrit,and platelet count indicated that YC further increased their levels when pigs were eating AF contaminated feed.Interactions(P < 0.05)on urea nitrogen and blood urea N to creatinine ratio indicated that YC further decreased their levels when feed were contaminated with AF.In conclusion,low level of 20 mg AF/kg under the regulatory level had minor effects on hematology without affecting growth performance,however the supplementation of 2 g/kg YC as a source ofβ-glucans and MOS in feed can improve feed intake and therefore the growth of pigs.

Dietary substitution of soybean oil with coconut oil in the absence of dietary antibiotics supports growth performance and immune function in nursery and grower pigs

Background:We hypothesized that supplementation of nursery and grower pig diets with coconut oil in the absence of antibiotics would yield maintenance of glucose homeostasis,growth performance,and immune function similar to what is achieved with nursery and grower pig diets containing antibiotics.Pigs received the same base treatment diets from d24(weaning)to d71 of age and had blood and fecal samples collected on d24,d31,d45 and d71 for measurement of whole blood glucose,serum insulin,cortisol and cytokines,and fecal microbiome.Pigs had weekly weights and daily feed consumption measured throughout the study.Animals were euthanized at d71 and subcutaneous fat and ileal contents were collected for assessment for fatty acids and microbiome,respectively.Diet treatments consisted of 2%soybean oil plus antibiotics(ABX;n=22),2%soybean oil without antibiotics(NABX;n=22),and 2%coconut oil without antibiotics(COC;n=22).Statistical analysis examined the effect of diet within each timepoint using a repeated measures ANOVA.Results:Pigs fed COC diet had decreased serum insulin levels,maintained feed intake,feed conversion and weight gain,and,based on serum cytokines and fecal microbiome,were immunologically similar to ABX-fed pigs.However,NABX-fed pigs performed similarly to the ABX-fed pigs in all parameters except for serum cytokines.Additionally,there was no difference in the incidence of diarrhea between any of the diet treatments.Conclusions:This study demonstrates that dietary antibiotics are not necessary to maintain growth performance in nursery and grower pigs.However,dietary antibiotics appear to modulate circulating cytokine levels.Dietary coconut oil is neither harmful nor helpful to growth performance or immune function in nursery and grower pigs but does modulate serum insulin levels.Therefore,while coconut oil fed at 2%by weight is a suitable substitute for dietary antibiotics,this study suggests that no substitute for dietary antibiotics is needed at all.

Intestinal microbiota and its interaction to intestinal health in nursery pigs

The intestinal microbiota has gained increased attention from researchers within the swine industry due to its role in promoting intestinal maturation,immune system modulation,and consequently the enhancement of the health and growth performance of the host.This review aimed to provide updated scientific information on the interaction among intestinal microbiota,dietary components,and intestinal health of pigs.The small intestine is a key site to evaluate the interaction of the microbiota,diet,and host because it is the main site for digestion and absorption of nutrients and plays an important role within the immune system.The diet and its associated components such as feed additives are the main factors affecting the microbial composition and is central in stimulating a beneficial population of microbiota.The microbiotaehost interaction modulates the immune system,and,concurrently,the immune system helps to modulate the microbiota composition.The direct interaction between the microbiota and the host is an indication that the mucosa-associated microbiota can be more effective in evaluating its effect on health parameters.It was demonstrated that the mucosa-associated microbiota should be evaluated when analyzing the interaction among diets,microbiota,and health.In addition,supplementation of feed additives aimed to promote the intestinal health of pigs should consider their roles in the modulation of mucosa-associated microbiota as biomarkers to predict the response of growth performance to dietary interventions.

Effects of the Standardized Ileal Digestible Lysine to Metabolizable Energy Ratio on Performance,Nutrient Digestibility,and Plasma Parameters of 10 to 28 kg Pigs

A total of 480 nursery pigs （Duroc x Landrace x Large White） were utilized in two experiments conducted to determine the effects of different ratios of standardized ileal digestible lysine （SID- Lys） to metabolizable energy （ME） ratio on the performance, nutrient digestibility, plasma urea nitrogen （PUN） ,and plasma free amino acids of 10 to 28 kg pigs. In Exp. 1, 192 pigs （ 10.58 kg） were assigned to one of four treatments. The treatments consisted of diets with a ME content of 3.2, 3.25, 3.3, or 3.35 Mcal/kg with a constant SID-Lys：ME ratio of 3.7 g/Mcal. The experiment lasted 28 days. Pigs which were fed the diets containing 3.3 and 3.35 Mcal/kg ME had lower feed intakes （ P 〈 0.05）than those fed 3.2 Mcal/kg. Feed efficiency was linearly improved with increasing dietary ME （ P 〈0.05）. Increasing the dietary ME level also increased （P 〈0.05 ） dry matter and energy digestibility. Therefore,3.3 Mcal/kg ME was selected for Exp. 2 in which 288 pigs （ 10.60 kg） were assigned to one of six treatments. Treatments consisted of SID-Lys： ME ratios of 3.1,3.3,3.5,3.7,3.9, or 4.1 g/Mcal with all diets providing 3.3 Mcal of ME/kg. Weight gain and feed efficiency were increased （P 〈0.05 ） as the SID-Lys：ME ratio in diet increased. Based on a straight broken-line model ,the estimated SID-Lys：ME ratio to maximize weight gain was 3.74.

Impacts of weaning age on dietary needs of whey permeate for pigs at 7 to 11 kg body weight

Background:Whey permeate is an effective lactose source for nursery pigs and the most benefits are obtained when pigs are at 7 to 11 kg BW.Altering weaning ages could cause different length of early-weaner phases until 7 kg BW and thus it would influence the dietary need of whey permeate during 7 to 11 kg BW of pigs.This study aimed to evaluate if weaning ages would affect the dietary needs of whey permeate for optimum growth performance of pigs at 7 to 11 kg BW.Methods:A total of 1,632 pigs were weaned at d 21(d 21.2±1.3)or d 25(d 24.6±1.1)after birth.All pigs had a common early-weaner feeds until they reached 7 kg BW.When pigs reached 7 kg BW within a weaning age group,they were allotted in a randomized complete block design(2×4 factorial).Two factors were weaning age groups(21 and 25 d of age)and varying whey permeate levels(7.50%,11.25%,15.00%,and 18.75%).Data were analyzed using the GLM and NLIN procedures of SAS for slope-ratio and broken-line analyses to determine the growth response to whey permeate and optimal daily whey permeate intake for the growth of the pigs weaned at different ages.Results:Pigs weaned at 21 d of age had a common diet for 11 d to reach 7 kg BW whereas pigs weaned at 25 d of age needed 2 d.The G:F of pigs weaned at 25 d of age responded to increased daily whey permeate intake greater(P<0.05)than pigs weaned at 21 d of age.Breakpoints were obtained(P<0.05)at 88 and 60 g/d daily whey permeate intake or 17.0%and 14.4%of whey permeate for G:F of pigs weaned at 21 and 25 d of age,respectively.Conclusion:Pigs weaned at an older age with a short early-weaner phase had a greater growth response to whey permeate intake compared with pigs weaned at a younger age with a long early-weaner phase.Altering weaning ages affected dietary needs of whey permeate for optimum growth performance of pigs from 7 to 11 kg BW.

Effect of the Standardized Ileal Digestible Lysine to Net Energy Ratio onthe Performance of Weaning Pigs Housed Under Commercial Conditions

Four experiments were conducted to investigate the effects of altering the standardized ileal digestible （SID） lysine to net energy （NE） ratio on the performance of weaned pigs housed under commercial conditions. Exp. 1 and 2 utilized a total of 720 crossbred pigs （Landrace x Yorkshire） weighing an average of 8.41 ± 0.72 kg in Exp. 1 and 6.94 ± 0. 63 kg in Exp. 2. The pigs were allotted to one of three treatments with six pens of 20 pigs per treatment. The treatments consisted of diets with different NE levels （2. 48, 2. 42, or 2. 36 Mcal/kg） and 1.21% SID-lysine. The diets were formulated using corn, soybean meal, wheat middlings, and broken rice. During both 14 day trials, the ADG of the pigs fed the diet providing 2.48 Mcal/kg NE was the highest among the three treatments （P 〈0.01 ）. The ADG of pigs fed diets providing 2.42 and 2.36 Mcal/kg NE did not differ （P 〉 0.05 ）. Exp. 3 and 4 were conducted to study the effects of different SID-lysine levels on the performance of weaned pigs fed diets containing 2.48 Mcal/kg NE. Exp. 3 and 4 utilized 720 crossbred pigs （ Landrace x Yorkshire） weighing 8.48±0.81 kg in Exp. 3 and 6.83 ±0.74 kg in Exp. 4. The pigs Were allotted to three treatments with six pens of 20 pigs per treatment. The treatments consisted of three diets with different SID-lysine levels （1.31%, 1.21%, or 1.11% ） and the same NE level （2.48 Mcal/kg）. Exp. 3 and 4 showed that the ADG of pigs fed the diet with 1.31% SID-lysine was higher than pigs fed the diet with 1.11% SID-lysine （P 〈0.01）. The ADG for pigs fed diets with 1.31% and 1. 21% SID-lysine did not differ （P 〉0. 05）. Based on the results of the present study, to maximize ADG of weaned pigs, the optimal level of NE is 2.48 Mcal/kg and the optimum level of SID-lysine is 1.31%.

Growth performance of nursery and grower-finisher pigs fed diets supplemented with benzoic acid

Two experiments were conducted to investigate the efficacy of benzoic acid on the growth performance of nursery and grower-finisher pigs. A randomized complete block design was used in both experiments with the initial body weight as the blocking factor. There were 3 treatments corresponding to 3 dietary levels of benzoic acid: 0, 0.3%, and 0.5%. In experiment 1, a total of 144 PIC L1050 barrows(initial body weight 7.1 ± 0.6 kg) were used with each treatment replicated 8 times. In experiment 2, a total of 288 PIC L1050 barrows(initial body weight 36.1 ± 3.6 kg) were used with each treatment replicated 16 times.There were 6 barrows in each replicate pen for both experiments. Experiments 1 and 2 lasted 28 and 70 days, respectively. In experiment 1, average daily gain(ADG) of all growth phases increased linearly(P < 0.05) with increasing supplementation of benzoic acid, which led to a linear improvement in average body weight on d 28(P < 0.05). There was also an improvement in feed conversion ratio(FCR) of d 0 to 14(linear effect: P < 0.05) and in average daily feed intake(ADFI) of d 14 to 28 and d 0 to 28(linear effect:P < 0.01). In experiment 2, ADG during d 0 to 35 and d 35 to 70 and average body weight on d 35 improved linearly(P < 0.05) with increasing supplementation of benzoic acid. Average daily gain of d 0 to70 and average body weight on d 70 increased significantly in a both linear and quadratic manner. There was a linear improvement in FCR in all growth phases(P < 0.05). In conclusion, the dietary inclusion of benzoic acid at the supplementation levels of 0.3% and 0.5% significantly improved the growth performance of nursery and grower-finisher pigs in the current study; the nursery pigs responded to the dietary supplementation of benzoic acid up to 0.5% linearly while the grower-finisher pigs achieved the optimal ADG at the calculated supplementation level of 0.36%.

Dietary inclusion of multispecies probiotics to reduce the severity of post-weaning diarrhea caused by Escherichia coli F18+ in pigs

This study was aimed to determine the efficacy of multispecies probiotics in reducing the severity of post-weaning diarrhea caused by enterotoxigenic Escherichia coli(ETEC)F18+on newly weaned pigs.Thirty-two pigs(16 barrows and 16 gilts,BW=6.99±0.33 kg)at 21 d of age were individually allotted in a randomized complete block design with 2×2 factorial arrangement of treatments.Pigs were selected from sows not infected previously and not vaccinated against ETEC.Pigs were fed experimental diets for 25 d based on 10 d phase 1 and 15 d phase 2.The factors were ETEC challenge(oral inoculation of saline solution or E.coli F18+at 2×109 CFU)and probiotics(none or multispecies probiotics 0.15%and 0.10%for phase 1 and 2,respectively).Body weight and feed intake were measured on d 5,9,13,19,and 25.Fecal scores were measured daily.Blood samples were taken on d 19 and 24.On d 25,all pigs were euthanized to obtain samples of digesta,intestinal tissues,and spleen.The tumor necrosis factor alpha(TNFα),malondialdehyde(MDA),peptide YY(PYY),and neuropeptide Y(NPY)were measured in serum and intestinal tissue.Data were analyzed using the MIXED procedure of SAS.The fecal score of pigs was increased(P<0.05)by ETEC challenge at the post-challenge period.The ETEC challenge decreased(P<0.05)jejunal villus height and crypt depth,tended to increase(P=0.056)jejunal TNFα,increased(P<0.05)ileal crypt depth,and decreased(P<0.05)serum NPY.The probiotics decreased(P<0.05)serum TNFα,tended to reduce(P=0.064)jejunal MDA,tended to increase(P=0.092)serum PYY,and increased(P<0.05)jejunal villus height,and especially villus height-to-crypt depth ratio in challenged pigs.Growth performance of pigs were not affected by ETEC challenge,whereas the probiotics increased(P<0.05)ADG and ADFI and tended to increase(P-0.069)G:F ratio.In conclusion,ETEC F18+challenge caused diarrhea,intestinal inflammation and morphological damages without affecting the growth performance.The multispecies probiotics enhanced growth performance by reducing intestinal inflammation,oxidative stress,morphological damages.

Interactions between maternal parity and feed additives drive the composition of pig gut microbiomes in the post‑weaning period

Background Nursery pigs undergo stressors in the post-weaning period that result in production and welfare chal-lenges.These challenges disproportionately impact the offspring of primiparous sows compared to those of mul-tiparous counterparts.Little is known regarding potential interactions between parity and feed additives in the post-weaning period and their effects on nursery pig microbiomes.Therefore,the objective of this study was to investigate the effects of maternal parity on sow and offspring microbiomes and the influence of sow parity on pig fecal microbi-ome and performance in response to a prebiotic post-weaning.At weaning,piglets were allotted into three treat-ment groups:a standard nursery diet including pharmacological doses of Zn and Cu(Con),a group fed a commercial prebiotic only(Preb)based on an Aspergillus oryzae fermentation extract,and a group fed the same prebiotic plus Zn and Cu(Preb+ZnCu).Results Although there were no differences in vaginal microbiome composition between primiparous and mul-tiparous sows,fecal microbiome composition was different(R^(2)=0.02,P=0.03).The fecal microbiomes of primiparous offspring displayed significantly higher bacterial diversity compared to multiparous offspring at d 0 and d 21 post-weaning(P<0.01),with differences in community composition observed at d 21(R^(2)=0.03,P=0.04).When analyzing the effects of maternal parity within each treatment,only the Preb diet triggered significant microbiome distinc-tions between primiparous and multiparous offspring(d 21:R^(2)=0.13,P=0.01;d 42:R^(2)=0.19,P=0.001).Composi-tional differences in pig fecal microbiomes between treatments were observed only at d 21(R^(2)=0.12,P=0.001).Pigs in the Con group gained significantly more weight throughout the nursery period when compared to those in the Preb+ZnCu group.Conclusions Nursery pig gut microbiome composition was influenced by supplementation with an Aspergillus oryzae fermentation extract,with varying effects on performance when combined with pharmacological levels of Zn and Cu or for offspring of different maternal parity groups.These results indicate that the development of nursery pig gut microbiomes is shaped by maternal parity and potential interactions with the effects of dietary feed additives.