Benzoic acid beneficially affects growth performance of weaned pigs which was associated with changes in gut bacterial populations,morphology indices and growth factor gene expression

This study was conducted to investigate the effects of benzoic acid (BA) on growth performance, intestinal development and intestinal barrier function in weaned pigs. Ninety weaned pigs were randomly assigned to one of three treatments: a basal diet (CON), the basal diet supplemented with 2000 mg/kg benzoic acid (BA1) and 5000 mg/kg benzoic acid (BA2). At the end of days 14 and 42, six pigs per treatment were randomly selected to collect plasma and intestinal samples. Results showed that BA supplementation not only improved final body weight, daily growth and feed conversion ratio from days 15 to 42 and days 1 to 42, but also decreased the activity of plasma diamine oxidase (day 42) and the pH values of jejunal contents (day 14) (p < 0.05). Ileal Bacillus populations (day 14) were increased by BA, while Escherichia coli counts in the ileum and caecum (day 42) were decreased (p < 0.05). Higher Lactobacillus counts occurred in the ileum (day 14, 42) of BA1‐fed piglets as compared to CON and BA2‐fed piglets (p < 0.05). In addition, BA supplementation increased the ratio of villus height to crypt depth (day 14, 42) and decreased the crypt depth (day 14) (p < 0.05). Growth‐stimulating factors (insulin‐like growth factor‐1, day 42; insulin‐like growth factor‐1 receptor, day 14, 42) and tight junction protein (occludin, day 14, 42; zonula occludens‐1, day 42)‐related gene mRNA levels were upregulated in the jejunum of piglets fed BA diets (p < 0.05). In conclusion, this study provides the first evidence that BA has beneficial effects on intestinal development and intestinal barrier function of weaned pigs, which can partly explain why growth performance of pigs was improved by dietary BA supplementation.     

Effects of supplemental palygorskite instead of zinc oxide on growth performance,apparent nutrient digestibility and fecal zinc excretion in weaned piglets

The aim of this study was to determine the effects of dietary supplementation of palygorskite instead of zinc oxide (ZnO) on growth performance, apparent nutrient digestibility and zinc contents in serum and feces in weaned piglets. One hundred and sixty‐five piglets (28 days of age, 7.10 ± 0.86 kg) were allotted to five treatments on the basis of weight and sex. Each treatment included three replicates of 11 piglets. The piglets were fed the same basal diet supplemented with 0 mg/kg (control group), 1800 mg/kg, 2400 mg/kg, or 3000 mg/kg palygorskite or 2500 mg/kg ZnO for 28 days. There was no significant difference for incidence of diarrhea among the four treatments during the 0–14‐day feeding period. Compared with the control group, piglets offered diets supplemented with 1800 mg/kg palygorskite had higher (P < 0.05) average daily gain (ADG) and crude protein digestibility. Fecal digestibility of energy in 1800 mg/kg palygorskite and ZnO groups were higher (P < 0.05) than that in the control group. Both the zinc concentrations in serum and fecal zinc excretion in palygorskite groups and control group were all lower (P < 0.05) than that in the ZnO group. In conclusion, dietary supplementation with 1800 mg/kg palygorskite can improve growth performance and nutrient digestibility and can also decrease zinc excretion in feces in weaned piglets.     

Dietary copper/zinc-loaded montmorillonite improved growth performance and intestinal barrier and changed gut microbiota in weaned piglets

The effects of copper/zinc-loaded montmorillonite (Cu/Zn-Mt) on growth performance, intestinal barrier and gut microbiota of weaned pigs were investigated in the present study. A total of 108 piglets (Duroc × Landrace × Yorkshire; 6.36 kg; weaned at 21 ± 1 d age) were used in this experiment. The pigs were randomly assigned to three treatments with six replicates, six pigs in each replicate. The three treatments were as follows: (1) control group: basal diet; (2) Cu/Zn-Mt group: basal diet supplemented with 39 mg/kg Cu and 75 mg/kg Zn as Cu/Zn-Mt; and (3) Cu +Zn +Mt group: basal diet supplemented with the mixture of copper sulphate, zinc sulphate and montmorillonite (equivalent to the copper and zinc in the Cu/Zn-Mt treatment). The results indicated that, compared with the pigs from control group, average daily gain and gain: feed ratio were increased and the faecal score on days 7 and 14 after weaning was decreased by supplementation of Cu/Zn-Mt; intestinal transepithelial electrical resistance (TER) and expressions of tight junction protein claudin-1 and zonula occludens-1 were increased, and intestinal permeability of fluorescein isothiocyanate-dextran 4 kDa was decreased by supplementation with Cu/Zn-Mt. According to the Illumina-based sequencing results, Cu/Zn-Mt supplementation increased the relative abundance of core bacteria (Lactococcus, Bacillus) at genus level and decreased the potentially pathogenic bacteria (Streptococcus and Pseudomonas) in colon of weaned piglets. However, the piglets fed with the mixture of copper sulphate, zinc sulphate and montmorillonite showed no effects in above parameters in comparison with the pigs from control group. In conclusion, dietary Cu/Zn-Mt could improve growth performance, decrease the diarrhoea and improve intestinal barrier and bacterial communities of weaned pigs. The results indicated that ‘loading’ of montmorillonite with Zn and Cu changed not only its chemical but also its nutritional properties.     

Dietary apple polyphenols supplementation enhances antioxidant capacity and improves lipid metabolism in weaned piglets

Apple polyphenols (APPs) are biologically active flavonoids that have antioxidant, anti‐inflammatory, improving insulin sensitivity, hypocholesterolaemic effect and antiviral properties. This study was conducted to explore effects of dietary APPs supplementation on antioxidant activities and lipid metabolism in weaned piglets. Fifty‐four weaned piglets (half male and female) were randomly divided into three groups with six replicates in each group and three piglets in each repetition. Piglets were fed control diet (basal diet) or a control diet supplemented with 400 mg/kg or 800 mg/kg APPs for 6 weeks. Blood and liver samples were collected to determine biochemical, antioxidant and lipid metabolism parameters. Here we showed that dietary APPs supplementation increased HDL‐C and decreased T‐CHO, TG and LDL‐C concentrations. Dietary APPs supplementation increased antioxidative capacity in serum and CAT activity in liver, and significantly increased the mRNA expressions of CAT, GST and SOD1 in liver. ACC mRNA level and LPL activity were tended to decrease by APPs. HMG‐CoAR, CTP7A1, CD36 and FATP1 mRNA levels were decreased by APPs, while LDL‐R, PGC‐1α, Sirt1 and CPT1b mRNA levels were increased by 400 mg/kg APPs. No alterations in growth performance were found in all treatments. This study firstly provided the evidence that dietary APPs supplementation could enhance systemic antioxidant capacity and improve lipid metabolism in weaned piglets. The mechanism by which APPs improve lipid metabolism might be through regulating hepatic cholesterol metabolism and increasing fatty acid oxidation, and decreasing fatty acid uptake and de novo synthesis.     

The effects of dietary supplementation with porous zinc oxide on growth performance,intestinal microbiota,morphology, and permeability in weaned piglets

The objective of this experiment was to evaluate the effects of dietary supplementation with porous zinc oxide (HiZox) on growth performance, intestinal microbiota, morphology, and permeability in weaned piglets. A total of 128 weaned piglets [(Landrace × Yorkshire) × Duroc] with an average body weight (BW) of (6.55 ± 0.25 kg; 21 d of age) were randomly assigned to four dietary treatments: (1) a corn‐soybean basal diet; (2) basal diet + 3,000 mg/kg conventional ZnO; (3) basal diet + 200 mg/kg HiZox; (4) basal diet + 500 mg/kg HiZox. The experiments lasted for 28 days. Incremental HiZox in the diet increased ADG (linear p = 0.015; quadratic p = 0.043) and ADFI (linear p = 0.027; quadratic p = 0.038), and the diarrhea index decreased linearly and quadratically (p < 0.01) as HiZox supplemented increased. Furthermore, supplementation with HiZox increased the amounts of Lactobacillus spp. (p < 0.05) in the ileum and cecum in comparison with that of control treatment or 3,000 mg/kg ZnO treatment, while decreased the populations of Escherichia coli, Clostridium coccoides, and Clostridium. leptum subgroup (p < 0.05) in the ileum and cecum relative to those in control treatment. The addition of HiZox increased the villus height and villus‐to‐crypt ratio (VC) of duodenum, jejunum, and ileum (p < 0.05), while decreased the crypt depth of jejunum (p < 0.05) and tended to reduce the crypt depth of duodenum (p < 0.10) compared with the control treatment. Piglets fed with 500 mg/kg HiZox had lower serum D‐lactate and diamine oxidase (DAO) than those fed with basal control diet or 3,000 mg/kg ZnO diet (p < 0.01). The results suggested that supplementation with HiZox modulated intestinal microbial composition and improved intestinal morphology, which may exert protective effects on the integrity of the mucosal barrier function of weaned piglets, was as efficacious as pharmaceutical doses of ZnO in enhancing growth performance, indicating that the HiZox may be a promising alternative to pharmaceutical doses of ZnO.     

Beta‐glucan from Agrobacterium sp. ZX09 improves growth performance and intestinal function in weaned piglets

Beta‐glucan is currently under consideration as an alternative to in‐feed antibiotics. The aim of the study was to investigate Agrobacterium sp. ZX09 beta‐glucan on intestinal morphology, cytokine concentration, mucin expression and microbial populations of weaning piglets. Pigs were randomly assigned to one of five dietary treatments supplemented with 0, 25, 50, 100 and 200 mg/kg beta‐glucan. Data showed an increase in ADG at the 100 mg/kg group (p = .03). A significant increase in villus height and reduction in crypt depth were fund in ileal tissue at the 100 mg/kg inclusion level (p < .05). Dietary supplementation of 100 mg/kg beta‐glucan enhanced IL‐10 concentration (p = .04) and gene expression of MUC1 and MUC2 (p < .05) in the jejunum. Dietary supplementation of 100 mg/kg beta‐glucan provoked the up‐regulation of Lactobacillus counts and down‐regulation of Escherichia coli counts in the caecum (p = .05). Data suggested that improved growth performance in response to beta‐glucan supplementation at 100 mg/kg in weaned piglets may be explained by the improved intestinal function.     

Evaluation of standardized ileal digestible lysine requirement for 8–20 kg pigs fed low crude protein diets

Two experiments were conducted to determine the standardized ileal digestible lysine (SID Lys) requirement for weaned pigs fed with low crude protein (CP) diet. In Experiment 1, 144 pigs were fed a normal CP (20%) diet with 12.3 g/kg SID Lys and five low CP (18.5%) diets providing SID Lys levels of 9.8, 11.1, 12.3, 13.5, and 14.8 g/kg, respectively, for 28 days. Reducing dietary CP from 20% to 18.5% enhanced (p < 0.05) the growth performance. The average daily gain (ADG) and gain to feed ratio (G:F) increased (linear and quadratic; p < 0.05), serum urea nitrogen (SUN) decreased (linear and quadratic; p < 0.05) as SID Lys increased. The SID Lys levels required to maximize ADG and optimize G:F were 12.8 and 13.1 g/kg using a curvilinear plateau model, and to minimize SUN was 13.4 g/kg using a two‐slope broken‐line model, which averaged 13.1 g/kg SID Lys. In Experiment 2, 18 pigs were used in a 12‐day N balance trial and received the same diets of Experiment 1. Total N excretion was decreased when dietary CP reduced and further decreased when SID Lys increased. Collectively, 1.5% dietary CP reduction improved the growth performance and decreased the N excretion; the optimal SID Lys requirement was at 13.1 g/kg of 8–20 kg pigs fed with 18.5% CP diet.     

Effects of multistrain probiotics on growth performance,nutrient digestibility,blood profiles,faecal microbial shedding,faecal score and noxious gas emission in weaning pigs

This experiment was conducted to investigate the efficacy of multistrain probiotics in weaning pigs. A total of 125 28‐day‐old weaning pigs [(Landrace × Yorkshire) × Duroc] with an initial average body weight (BW) of 7.26 ± 0.76 kg were randomly allotted into 5 treatments, 5 replicate pens/treatment with 5 pigs/pen for 42‐day experiment. Dietary treatments were as follows: CON, basal diet; PC1, CON + 0.01% multistrain probiotics; PC2, CON + 0.03% multistrain probiotics; PC3, CON + 0.06% multistrain probiotics; PC4, CON + 0.1% multistrain probiotics. On day 14, pigs fed the PC4 diet had higher BW gain than pigs fed the CON diet. On day 42, pigs fed multistrain probiotics supplementation diets had higher BW gain than pigs fed the CON diet. From days 1 to 14, pigs fed the PC2, PC3 and PC4 diets had higher (p < 0.05) ADG than pigs fed the CON diet. From day 15 to 42, pigs fed the multistrain probiotics supplementation diets had higher (p < 0.05) average daily gain (ADG) and gain: feed ratio (G:F) than pigs fed the CON diet. In the overall period, pigs fed the multistrain probiotics supplementation diets had higher (p < 0.05) ADG and pigs fed the PC2 and PC4 diets had higher (p < 0.05) G:F than pigs fed the CON diet. On day 42, pigs fed the PC4 diet had higher (p < 0.05) apparent total tract digestibility (ATTD) of dry matter (DM), nitrogen (N) and gross energy (GE), faecal Lactobacillus counts and lower (p < 0.05) E. coli counts and NH₃ emission than pigs fed the CON diet. Pigs fed the multistrain probiotics supplementation diets had lower (p < 0.05) H₂S and total mercaptans emissions than pigs fed the CON diet. Conclusions, dietary supplementation with 0.1% probiotics improved growth performance, nutrition digestibility and intestinal microflora balance and decreased faecal noxious gas emissions in weaning pigs.     

Effects of dietary supplementation of Lycium barbarum polysaccharides on growth performance,immune status,antioxidant capacity and selected microbial populations of weaned piglets

Lycium barbarum polysaccharides (LBPs) are a complex mixture of highly branched and partially characterised polysaccharides and proteoglycans extracted from the goji berry. This mixture has great potential as a novel feed supplement for pigs. Two trials were conducted to evaluate the effects of supplementation with LBPs on the growth performance, immune status, antioxidant capacity and selected intestinal microbial populations in weaned piglets. In trial 1, a total of 400 weaned piglets [(Yorkshire × Landrace) × Duroc] with an average body weight (BW) of 6.34 ± 0.16 kg (21 days of age) were divided into five groups and fed a basal diet (control group) or a basal diet containing 1,000, 2,000, 4,000 or 6,000 mg/kg LBPs (supplemented at the expense of corn). Supplementation with 4,000 or 6,000 mg/kg LBPs for 2 weeks significantly increased the average daily gain (ADG) and average daily feed intake (ADFI) of the pigs compared with the control group (p < .05). In trial 2, thirty-two 21-days-old weaned piglets (BW: 6.33 ± 0.11 kg) were allotted to a control group (fed with a basal diet) or an experimental group (basal diet containing 4,000 mg/kg LBPs). The experiment lasted for 14 days. Pigs fed LBP diets exhibited an increased ADG and ADFI, and a decreased diarrhoeal incidence compared with those fed the basal diets (p < .05). Supplementation with LBPs increased the serum IgG and IgM levels (p < .05). Dietary LBPs effectively promoted antioxidant defence properties through enhancing the activities of serum, liver superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), in addition to decreasing the malondialdehyde (MDA) content (p < .05). The addition of LBPs increased the amounts of Bacteroidetes in the ileum and caecum and the caecal contents of Lactobacillus spp. and Bifidobacterium spp. (p < .05), while decreased the populations of Escherichia coli and Firmicutes in the ileum and caecum (p < .05) compared with the control group. Our results suggest that dietary supplementation with LBPs can enhance growth performance, immune status and antioxidant capacity, and improve the intestinal microbial populations of weaned piglets.     

Effects of Piper sarmentosum extract on the growth performance,antioxidant capability and immune response in weaned piglets

The biological properties of Piper sarmentosum render it a potential substitute for antibiotics in livestock feed. This study evaluated the effects of P. sarmentosum extract (PSE) on the growth performance, antioxidant capability and immune response of weaned piglets. Eighty 21‐d‐old weaned piglets were selected and randomly allocated to one of four dietary treatments with five replicates of four pigs each. The dietary treatments consisted of a basal diet supplemented with 0 (T0), 50 (T50), 100 (T100) or 200 (T200) mg/kg PSE. The feeding trial lasted 4 weeks. The results revealed that the T50 group had the highest average daily gain (ADG) and average daily feed intake (ADFI) throughout the feeding trial (p < 0.05). Additionally, the T50 group had higher (p < 0.05) serum glutathione peroxidase activity (GSH‐Px) and lower (p < 0.05) serum malondialdehyde (MDA) levels than the T0 group at 4 weeks post‐weaning (p < 0.05). Serum levels of interleukin‐1β (IL‐1β) and tumour necrosis factor‐α (TNF‐α) decreased, while serum levels of interleukin‐4 (IL‐4), interleukin‐10 (IL‐10) and transforming growth factor‐β (TGF‐β) increased by PSE supplementation at 4 weeks post‐weaning (p < 0.05). PSE supplementation upregulated the mRNA expression of IL‐4, IL‐10 and TGF‐β and downregulated the mRNA expression of TNF‐α, IL‐1β and interleukin‐6 (IL‐6) in the ileal mucosal layer of piglets (p < 0.05). In summary, our study findings revealed that PSE supplementation improved the antioxidant capability, and reduced inflammation, which may be beneficial to weaned piglet health.     

Pharmacokinetics of marbofloxacin in pigs after intravenous and intramuscular administration of a single dose of 8 mg/kg: dose proportionality,influence of the age of the animals and urinary elimination

The pharmacokinetics of marbofloxacin in pigs were evaluated as a function of dose and animal age following intravenous and intramuscular administration of a 16% solution (Forcyl^®). The absolute bioavailability of marbofloxacin as well as the dose proportionality was evaluated in 27‐week‐old fattening pigs. Blood PK and urinary excretion of marbofloxacin were evaluated after a single intramuscular dose of 8 mg/kg in 16‐week‐old male pigs. An additional group of 12‐week‐old weaned piglets was used for the evaluation of age‐related kinetics. The plasma and urine concentration of marbofloxacin was determined using a HPLC method. Pharmacokinetic parameters were calculated using noncompartmental methods. After intravenous administration in 27‐week‐old fattening pigs, the total body clearance was 0.065 L/h·kg. After intramuscular administration to the same animals, the mean observed C_max was 6.30 μg/mL, and the AUC_INF was 115 μg·h/mL. The absolute bioavailability was 91.5%, and dose proportionality was shown within the dose range of 4–16 mg/kg. The renal clearance was about half of the value of the total clearance. The total systemic clearance values significantly decreased as a function of age, being 0.092 L/h·kg and 0.079 L/h·kg in pigs aged 12 and 16 weeks, respectively.     

Rearing conditions affected responses of weaned pigs to organic acids showing a positive effect on digestibility,microflora and immunity

Three experiments were conducted to assess the response of weaned pigs to organic acid SF3, which contains 34% calcium formate, 16% calcium lactate, 7% citric acid and 13% medium chain fatty acids. Dietary treatments had no effect on growth performance of piglets (21‐day weaning) fed the commercial prestart diet for 1 week before receiving the experimental diets supplemented with SF3 at 0, 3 or 5 g/kg diet (Exp. 1), whereas diarrhea frequency averaged across a week was decreased by SF3 supplementation (5 g/kg diet) in piglets fed the experimental diets immediately after weaning (Exp. 2). In Exp. 3, piglets (28‐day weaning) were fed the control (containing pure colistin sulfate and enramycin, respectively, at 20 mg/kg diet) for 1 week and then were fed the control or SF3‐supplemented (5 g/kg diet) diet for 2 weeks. The SF3‐fed piglets had greater apparent ileal digestibility of calcium and dry matter, while also demonstrating greater overall gross energy, up‐regulated jejunal expression of sodium‐glucose cotransporter‐1 and transforming growth factor‐β, down‐regulated jejunal expression of tumor necrosis factor (TNF)‐α, higher ileal Lactobacillus, with lower total bacteria content, lower plasma TNF‐α but higher IgG levels than the control‐fed piglets. Collectively, SF3 consumption improved diarrhea resistance of weaned pigs by improving nutrient digestibility, piglet immunity and intestinal bacteria profile. © 2016 Japanese Society of Animal Science     

Effect of pectin oligosaccharides and zinc chelate on growth performance,zinc status,antioxidant ability,intestinal morphology and short‐chain fatty acids in broilers

A 42‐day trial was conducted to investigate the effect of pectin oligosaccharides (POS) and zinc chelate (Zn‐POS) on growth performance, antioxidant ability, zinc status, intestinal morphology and short‐chain fatty acids in broilers. A total of 324 1‐day‐old Arbor Acres broilers were randomly assigned to three treatments with six cages of 18 chicks. Treatments were: (a) Control, 80 mg/kg Zn from ZnSO₄; (b) POS, 80 mg/kg Zn from ZnSO₄ + 482 mg/kg POS (the same amount of POS as treatment 3); and (c) Zn‐POS, 80 mg/kg zinc from Zn‐POS. Compared to the Control, both POS and Zn‐POS supplementation increased average daily gain and reduced the mortality during day 22–42, and only Zn‐POS supplementation decreased the ratio of feed to gain during day 22–42 and 1–42. Moreover, both POS and Zn‐POS supplementation improved Zn status and gut function as evidenced by increased metallothionein concentrations in the pancreas, villus height in the duodenum and isobutyrate concentrations in the caecal digesta. Additionally, Zn‐POS supplementation increased gene expressions of metallothionein, Zn transporter 1, Zn transporter 2 in the pancreas, nuclear factor erythroid 2‐related factor 2 in the liver, the concentrations of acetate, propionate, butyrate and total SCFA in the caecal digesta and the villus height to crypt depth ratio in the duodenum and jejunum, whereas decreased the crypt depth in these two tissues. Altogether, our results revealed that dietary POS or Zn‐POS supplementation benefited growth performance, Zn status, antioxidant ability and gut function of broilers. Supplementing Zn‐POS in the form of chelate was more effective than feeding POS or ZnSO₄ separately.     

Methyl donors dietary supplementation to gestating sows diet improves the growth rate of offspring and is associating with changes in expression and DNA methylation of insulin‐like growth factor‐1 gene

The study aimed to investigate the effects of maternal dietary methyl donors on the performance of sows and their offspring, and the associated hepatic insulin‐like growth factor‐1 (IGF‐1) expression of the offspring. A total of 24 multiparous sows were randomly fed the control (CON) or the CON diet supplemented with methyl donors (MD) at 3 g/kg betaine, 15 mg/kg folic acid, 400 mg/kg choline and 150 μg/kg VB₁₂, from mating until delivery. After farrowing, sows were fed a common lactation diet through a 28‐days lactation period and six litters per treatment were selected to be fed until at approximately 110 kg BW. Maternal MD supplementation resulted in greater birthweight (p < 0.05) and increased the piglet weights (p < 0.01) and litter weights (p < 0.05) at the age of day 28, compared with that in CON group. The offspring pigs in the MD group had greater ADG (p < 0.05) and tended to lower F:G ratio (p = 0.07) compared with that of CON group from day 28 to 180 of age. The offspring pigs from MD group had greater serum IGF‐1 concentrations and expressions of hepatic IGF‐1 gene and muscular IGF‐1 receptor (IGF‐1r) protein at birth (p < 0.05), and greater hepatic IGF‐1 protein (p = 0.03) and muscular IGF‐1r gene expressions (p < 0.05) at slaughter, than that from the CON group. Moreover, the methylation at the promoter of IGF‐1 gene in the liver of newborn piglets and finishing pigs was greater in the MD group than that of the CON group (p < 0.05). In conclusion, maternal MD supplementation throughout gestation could enhance the birthweight and postnatal growth rate of offspring, associated with an increased expression of the IGF‐1 gene and IGF‐1r, as well as the altered DNA methylation of IGF‐1 gene promotor.     

Dietary lysine requirement for 7–16 kg pigs fed wheat–corn–soybean meal‐based diets

Two experiments were conducted to determine the lysine requirement of weaned pigs [Duroc × (Yorkshire × Landrace)] with an average initial BW of 7 kg and fed wheat–corn–soybean meal‐based diets. The experiments were conducted for 21 days during which piglets had free access to diets and water. Average daily gain (ADG), average daily feed intake (ADFI) and gain to feed ratio (G:F) were determined on day 7, 14 and 21. Blood samples were collected on day 0 and 14 to determine plasma urea nitrogen (PUN) concentration. In experiment 1, 96 weaned pigs were housed four per pen and allocated to four dietary treatments with six replicates per treatment. The diets contained 0.99%, 1.23%, 1.51% and 1.81% standardized ileal digestible (SID) lysine, respectively, corrected analysed values. The rest of the AA were provided to meet the ideal AA ratio for protein accretion. Increasing dietary lysine content linearly increased (p < 0.05) ADG and G:F. In experiment 2, 90 piglets were housed three per pen and allocated to five dietary treatments with six replicates per treatment. The five diets contained 1.03%, 1.25%, 1.31%, 1.36% and 1.51% SID lysine, respectively, corrected analysed values. Increasing dietary lysine content linearly increased (p < 0.05) G:F, linearly decreased (p < 0.05) day‐14 PUN and quadratically (p < 0.05) increased ADG and ADFI. The ADG data from experiment 2 were subjected to linear and quadratic broken‐lines regression analyses, and the SID lysine requirement was determined to be 1.29% and 1.34% respectively. On average, optimal dietary SID lysine content for optimal growth of 7–16 kg weaned piglets fed wheat–corn–SBM‐based diets was estimated to be 1.32%; at this level, the ADG and ADFI were 444 and 560 g, respectively, thus representing an SID lysine requirement, expressed on daily intake basis as, 7.4 g/day or 16.76 mg/g gain.     

Effect of Forsythia suspensa extract and chito‐oligosaccharide alone or in combination on performance,intestinal barrier function,antioxidant capacity and immune characteristics of weaned piglets

We investigated the effects of Forsythia suspensa extract (FSE) and chito‐oligosaccharide (COS), alone or together, on performance and health status of weaned piglets. The treatments included a basal diet and three diets with 160 mg/kg COS, 100 mg/kg FSE, or 100 mg/kg FSE and 160 mg/kg COS. Supplementation with COS or FSE alone improved (P < 0.01) average daily gain and feed conversion ratio compared with the basal diet in the first 2 weeks. On day 14, COS or FSE supplementation separately produced stronger (P < 0.01) serum total antioxidant capacity and glutathione peroxidase activities and lower serum endotoxin (P < 0.05) and malondialdehyde (P < 0.01) concentrations, generated higher (P < 0.01) serum complement 4 concentration, peripheral blood lymphocyte proliferation and serum‐specific ovalbumin antibody level than the basal diet. No differences in oxidative injury and immunity indices were detected on day 28. The combined FSE and COS produced similar results compared with FSE or COS when given alone. These data indicate FSE or COS can increase performance by modulating intestinal permeability, antioxidant status and immune function in younger pigs. There appears to be similar advantage in feeding the additives in combination over those obtained from feeding them separately.     

Nutrient digestibility, blood profiles and fecal microbiota are influenced by chitooligosaccharide supplementation of growing pigs

This study was conducted to evaluate the effects of dietary chitooligosaccharide (COS) supplementation on growth performance, nutrient digestibility, blood profiles and fecal microbiota in growing pigs. A total of 144 [(Landrace × Yorkshire) × Duroc] pigs with an initial body weight of 23.6 ± 1.1 kg were allotted to one of the following dietary treatments: 1) basal diet; 2) basal diet with 44 mg/kg of tylosin (100 mg/kg tylosin); 3) basal diet with 5 g/kg of COS and 4) basal diet with 5 g/kg COS and 44 mg/kg tylosin. There were nine replications per treatment with four pigs per pen. Throughout the experiment, pigs that were treated with a combination of COS and tylosin had a lower ADFI (P = 0.02) and higher gain/feed ratio (P < 0.05) than the other treatments. In addition, administration of either COS or tylosin alone significantly increased the digestibility of dry matter, nitrogen and gross energy (P < 0.05). The red blood cell (RBC) and white blood cell (WBC) counts, as well as the serum albumin concentrations were not affected by COS or tylosin supplementation. However, the lymphocyte proportion and serum total protein concentration were increased in pigs fed tylosin supplemented diets compared with those pigs fed diets not supplemented with tylosin (P < 0.05). Administration of tylosin significantly increased serum IgG concentration (P = 0.02); however, treatment with COS or tylosin supplementation had no effect on the total cholesterol or triglyceride concentrations. The serum HDL cholesterol concentration was significantly increased in pigs treated with COS (P = 0.02) compared to the pigs fed diets without COS. The COS administration also decreased the number of fecal Escherichia coli (P < 0.01), whereas the number of fecal Lactobacilli was not influenced by either COS or tylosin administration. Results of the current study indicate that dietary supplementation of COS can improve nutrient digestibility and haematological profiles, as well as decrease of fecal E. coli populations in growing pigs.     

Zinc methionine and laminarin have growth‐enhancing properties in newly weaned pigs influencing both intestinal health and diarrhoea occurrence

Three experiments were conducted to investigate the interaction between zinc methionine (ZnM) and laminarin (LAM) on piglet growth performance and intestinal health post‐weaning. Experiment 1 was designed as 2 × 2 factorial with four treatments [n = 8, weaning age (WA) 24 days, live weight (LW) 7.15 kg]: (i) basal diet (BD); (ii) BD + 500 mg/kg ZnM; (iii) BD + 300 mg/kg LAM; and (iv) BD + 500 mg/kg ZnM + 300 mg/kg LAM. There was an interaction (p < 0.05) between LAM and ZnM. Pigs that were offered the LAM diet had a similar performance to the BD. However, when combining LAM with ZnM, pigs had reduced average daily gain (ADG), gain‐to‐feed ratio (G:F) and LW at slaughter at day 8 post‐weaning compared to the ZnM. Both LAM and ZnM improved the small intestinal morphology of the pigs at day 8 post‐weaning. Experiment 2 was designed as 2 × 2 factorial with four dietary treatments (n = 9, WA 24 days, LW 7.32 kg): (i) BD; (ii) BD + 500 mg/kg ZnM; (iii) BD + 175 mg/kg LAM; and (iv) BD + 500 mg/kg ZnM + 175 mg/kg LAM. The ADG and average daily feed intake were improved between day 0 and 31 PW when pigs were offered a LAM diet (p < 0.01). Faecal scores were reduced between day 0 and day 31 post‐weaning with ZnM (p < 0.001). Experiment 3 consisted of four dietary treatments (n = 10, WA 24 days, LW 7.32 kg): (i) BD; (ii) BD + 3300 mg/kg zinc oxide (ZnO); (iii) BD + 500 mg/kg ZnM; and (iv) BD + 175 mg/kg LAM. Pigs that were offered the ZnO diet had an increased ADG compared to the BD or ZnM diets (p < 0.01). Pigs that were offered the LAM diet had increased ADG compared to the ZnM diet (p < 0.05). Faecal scores were reduced between day 0 and day 31 PW with ZnM or ZnO supplementation (p < 0.001). In conclusion, the inclusion of 175 mg/kg LAM and ZnO improved ADG while both ZnO and ZnM reduced the faecal scores post‐weaning.     

Effects of essential oil supplementation of a low‐energy diet on performance,intestinal morphology and microflora,immune properties and antioxidant activities in weaned pigs

A total of 144 weaned piglets were used to evaluate the effects of essential oil (EO) supplementation of a low‐energy diet on performance, apparent nutrient digestibility, small intestinal morphology, intestinal microflora, immune properties and antioxidant activities in weaned pigs. Pigs received a low‐energy diet (negative control, NC, digestible energy = 3250 kcal/kg), NC plus 0.025% EO or a positive control diet (PC, digestible energy = 3400 kcal/kg) for 28 days. Growth performance was similar between the EO group and PC group. However, EO supplementation increased (P < 0.05) average daily gain and the apparent digestibility of dry matter, crude protein and energy compared with pigs fed the NC diet. Greater (P < 0.05) villus height and lower (P < 0.05) counts of Escherichia coli and total anaerobes in the rectum in the EO group were observed compared with NC or PC groups. Pigs fed EO diet had higher (P < 0.05) concentrations of albumin, immunoglobulin A (IgA), IgG and total antioxidant capacity and lower fecal score than pigs fed the PC and NC diets. Above all, this study indicates that supplementation of EO to a low‐energy pig diet has beneficial results and obtains similar performance compared with normal energy (PC) diet.     

Effect of resveratrol on growth performance,rectal temperature and serum parameters of yellow‐feather broilers under heat stress

This study investigated the effect of dietary resveratrol supplementation on growth performance, rectal temperature, and serum parameters of yellow‐feather broilers under heat stress. A total of 480 yellow‐feather broilers (28‐day‐old) were randomly allotted to five groups with six replicates. A thermoneutral group (TN) (24 ± 2°C) received a basal diet and another four heat‐stressed groups (37 ± 2°C for 8 hr/day and 24 ± 2°C for the remaining time) were fed the basal diet or basal diet with 200, 350, and 500 mg/kg resveratrol for 14 consecutive days. The results revealed that resveratrol supplementation improved average daily gain (p = 0.001), and decreased (p < 0.05) rectal temperature from d 3 when compared with heat‐stressed group without resveratrol. In addition, supplementation with resveratrol at 350 or 500 mg/kg lowered (p < 0.05) the contents of corticosterone, adrenocorticotropic hormone, cholesterol, triglycerides, uric acid, malonaldehyde, and activities of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, increased (p < 0.05) the levels of triiodothyronine, the ratio of triiodothyronine to thyroxine, total protein, glutathione, and activities of alkaline phosphatase, total superoxide dismutase, catalase, and glutathione peroxidase, though with few fluctuation. In conclusion, supplementation with resveratrol can improve the growth performance by positively regulating serum metabolic parameters and alleviating tissue oxidant damage of broilers under heat stress.