Interactions of dietary protein and threonine on growth performance in Pekin ducklings from 1 to 14 days of age.

The present study was conducted to investigate the effects of dietary crude protein (CP) on threonine requirements by determining the interactions of dietary CP levels (16.0, 17.5, 19.0, 20.5, and 22.0%) and supplemental threonine levels (0, 0.07, 0.14, 0.21, and 0.28%) on growth performance of Pekin ducks from 1 to 14 days of age. A total of 1,200 one-day-old male Pekin ducks was randomly allotted to 1 of 25 dietary treatments with 6 replicate pens of 8 birds per pen for each treatment. The results showed that dietary CP and threonine levels affected the average daily feed intake (ADFI, P < 0.0001), average daily gain (ADG, P < 0.0001), ratio of feed/gain (F/G, P < 0.0001) of Pekin ducks, and had an interactions on the ADFI, ADG, F/G (P < 0.0001). The ADG was increased linearly (P < 0.002) and then reached a plateau as the dietary threonine increased at all CP diets. According to the estimation of broken-line models, the dietary threonine requirements at 16.0, 17.5, 19.0, 20.5, and 22.0% CP diets for optimal ADG of ducks were 0.56, 0.61, 0.60, 0.63, and 0.67% when expressed as percentage of diet, or 44.22, 47.65, 47.50, 48.30, and 50.39% when expressed as percentage of dietary lysine, or 3.45, 3.44, 3.12, 3.27, and 2.98% when expressed as percentage of dietary CP, respectively. Threonine requirements of Pekin ducks from 1 to 14 days of age were affected by dietary CP levels according to the Student t test results, but had no difference among the moderate CP level diets (17.5, 19, and 20.5%) when expressed as a percentage of diet or dietary lysine. It was concluded that dietary CP levels affected the threonine requirements of Pekin ducks from 1 to 14 days of age, but threonine requirements were constant within the limiting CP level range (17.5 to 20.5%) with a good balance of dietary amino acid, and were approximately 0.60 to 0.63% of diet or 47.5 to 48.3% of dietary lysine.

Threonine supplementation reduces dietary protein and improves lipid metabolism in Pekin ducks.

1. This study was conducted to investigate the efficiency of threonine (Thr) supplementation on reducing dietary crude protein (CP) content and the effects of Thr on lipid metabolism in Pekin ducks. The effects of dietary CP concentration (160, 190 and 220 g/kg) and Thr supplemental concentration (0, 0.7, 1.4, 2.1 and 2.8 g/kg) on growth performance, carcass, liver lipid and plasma profiles were determined in Pekin ducks from 1-21 d of age. 2. A total of 720-d-old male Pekin ducks were randomly allotted to 1 of 15 dietary treatments with 6 replicate cages of 8 birds per cage for each treatment according to average body weight. 3. Dietary Thr supplementation improved growth performance and breast muscle percentage at all CP diets, and ducks fed Thr-supplemented diets had higher plasma concentrations of some plasma amino acids. Thr supplementation reduced the concentrations of total lipid, triglyceride, cholesterol in liver, and plasma low density lipoprotein cholesterin concentration at 160 and 190 g/kg CP, whereas it increased triglyceride concentration at 160 g/kg CP. 4. Thr requirements based on quadratic broken-line model estimation were 6.6 and 7.0 g/kg for optimal average daily gain (ADG), and 6.7 and 7.3 g/kg for breast muscle percentage of Pekin ducks from 1-21 d of age at 190 and 220 g/kg CP, respectively. The dietary Thr requirements and estimated ADG (55.18 vs. 55.86 g/d/bird) and breast muscle percentage (2.79% vs. 2.75%) of Pekin ducks did not differ between 190 and 220 g/kg CP according to the t-test results. 5. Dietary CP level could be reduced to 190 g/kg in Pekin ducks from 1-21 d of age with Thr supplementation to balance dietary amino acids, and Thr supplementation prevented excess liver lipid deposition in this instance.

Dietary supplemented antimicrobial peptide microcin J25 improves the growth performance, apparent total tract digestibility, fecal microbiota, and intestinal barrier function of weaned pigs.

Microcin J25 (MccJ25) is an antimicrobial peptide produced by a fecal strain of Escherichia coli containing 21 AA. This study was performed primarily to evaluate the effects of MccJ25 as a potential substitute for antibiotics (AB) on growth performance, nutrient digestibility, fecal microbiota, and intestinal barrier function in weaned pigs. In the present study, 180 weaned pigs (7.98 ± 0.29 kg initial BW) were randomly assigned to 1 of 5 treatments, including a basal diet (CON) and CON supplemented with AB (20 mg/kg colistin sulfate; ABD) or 0.5, 1.0, and 2.0 mg/kg MccJ25. On d 0 to 14, dietary supplementation with MccJ25 and ABD had positive effects on ADG, ADFI, diarrhea incidence, and G:F ( < 0.05). Pigs fed the 2.0 mg/kg MccJ25 diet had greater ADG ( < 0.05) and marginally greater G:F ( < 0.10) compared with pigs fed the ABD diet. Compared with the CON diet, the 2.0 mg/kg MccJ25 diet sharply improved ( < 0.05) ADG and G:F and decreased ( < 0.05) diarrhea incidence (d 15 to 28 and d 0 to 28). Apparent digestibility of nutrients in pigs fed 1.0 and 2.0 mg/kg MccJ25 was improved ( < 0.05) compared with that of pigs fed CON and ABD. The serum cytokines IL-6 and IL-1ß and tumor necrosis factor-α levels in pigs fed MccJ25 were greater than in pigs fed CON ( < 0.05). Additionally, the IL-10 concentration in pigs fed MccJ25 was sharply increased ( < 0.05) compared with that of pigs fed CON. Pigs fed 1.0 and 2.0 mg/kg MccJ25 diets had remarkably decreased lactate, diamine oxidase, and endotoxin concentrations and fecal numbers ( < 0.05) and improved fecal and numbers ( < 0.05). Compared with the ABD diet, the diet containing 2.0 mg/kg MccJ25 did not increase lactate, diamine oxidase, and endotoxin (d 14) concentrations ( < 0.05) or decrease the and (d 28) numbers ( < 0.05). The diets containing 1.0 and 2.0 mg/kg MccJ25 and ABD (d 28) improved lactate concentration and short-chain fatty acid concentrations, including acetate, propionate, and butyrate, in feces ( < 0.05). Moreover, the pigs fed 2.0 mg/kg MccJ25 had greater lactate, butyrate (d 14), and propionate concentrations than the pigs fed the ABD diet ( < 0.05). In conclusion, dietary supplemented MccJ25 effectively improved performance, attenuated diarrhea and systematic inflammation, enhanced intestinal barrier function, and improved fecal microbiota composition of weaned pigs. Therefore, MccJ25 could be a potential effective alternative to AB for weaned pigs.

Branched-chain Amino Acids are Beneficial to Maintain Growth Performance and Intestinal Immune-related Function in Weaned Piglets Fed Protein Restricted Diet.

As a novel approach for disease control and prevention, nutritional modulation of the intestinal health has been proved. However, It is still unknown whether branched-chain amino acid (BCAA) is needed to maintain intestinal immune-related function. The objective of this study was to determine whether BCAA supplementation in protein restricted diet affects growth performance, intestinal barrier function and modulates post-weaning gut disorders. One hundred and eight weaned piglets (7.96±0.26 kg) were randomly fed one of the three diets including a control diet (21% crude protein [CP], CON), a protein restricted diet (17% CP, PR) and a BCAA diet (BCAA supplementation in the PR diet) for 14 d. The growth performance, plasma amino acid concentrations, small intestinal morphology and intestinal immunoglobulins were tested. First, average daily gain (ADG) (p<0.05) and average daily feed intake (ADFI) (p<0.05) of weaned pigs in PR group were lower, while gain:feed ratio was lower than the CON group (p<0.05). Compared with PR group, BCAA group improved ADG (p<0.05), ADFI (p<0.05) and feed:gain ratio (p<0.05) of piglets. The growth performance data between CON and BCAA groups was not different (p>0.05). The PR and BCAA treatments had a higher (p<0.05) plasma concentration of methionine and threonine than the CON treatment. The level of some essential and functional amino acids (such as arginine, phenylalanine, histidine, glutamine etc.) in plasma of the PR group was lower (p<0.05) than that of the CON group. Compared with CON group, BCAA supplementation significantly increased BCAA concentrations (p<0.01) and decreased urea concentration (p<0.01) in pig plasma indicating that the efficiency of dietary nitrogen utilization was increased. Compared with CON group, the small intestine of piglets fed PR diet showed villous atrophy, increasing of intra-epithelial lymphocytes (IELs) number (p<0.05) and declining of the immunoglobulin concentration, including jejunal immunoglobulin A (IgA) (p = 0.04), secreted IgA (sIgA) (p = 0.03) and immunoglobulin M (p = 0.08), and ileal IgA (p = 0.01) and immunoglobulin G (p = 0.08). The BCAA supplementation increased villous height in the duodenum (p<0.01), reversed the trend of an increasing IELs number. Notably, BCAA supplementation increased levels of jejunal and ileal immunoglobulin mentioned above. In conclusion, BCAA supplementation to protein restricted diet improved intestinal immune defense function by protecting villous morphology and by increasing levels of intestinal immunoglobulins in weaned piglets. Our finding has the important implication that BCAA may be used to reduce the negative effects of a protein restricted diet on growth performance and intestinal immunity in weaned piglets.

Estimation of the standardized ileal digestible valine to lysine ratio required for 25- to 120-kilogram pigs fed low crude protein diets supplemented with crystalline amino acids.

Four 28-d experiments were conducted to determine the standardized ileal digestible (SID) valine (Val) to lysine (Lys) ratio required for 26- to 46- (Exp. 1), 49- to 70- (Exp. 2), 71- to 92- (Exp. 3), and 94- to 119-kg (Exp. 4) pigs fed low CP diets supplemented with crystalline AA. The first 3 experiments utilized 150 pigs (Duroc × Landrace × Large White), while Exp. 4 utilized 90 finishing pigs. Pigs in all 4 experiments were randomly allocated to 1 of 5 diets with 6 pens per treatment (3 pens of barrows and 3 pens of gilts) and 5 pigs per pen for the first 3 experiments and 3 pigs per pen for Exp. 4. Diets for all experiments were formulated to contain SID Val to Lys ratios of 0.55, 0.60, 0.65, 0.70, or 0.75. In Exp. 1 (26 to 46 kg), ADG increased (linear, = 0.039; quadratic, = 0.042) with an increasing dietary Val:Lys ratio. The SID Val:Lys ratio to maximize ADG was 0.62 using a linear broken-line model and 0.71 using a quadratic model. In Exp. 2 (49 to 70 kg), ADG increased (linear, = 0.021; quadratic, = 0.042) as the SID Val:Lys ratio increased. G:F improved (linear, = 0.039) and serum urea nitrogen (SUN) decreased (linear, = 0.021; quadratic, = 0.024) with an increased SID Val:Lys ratio. The SID Val:Lys ratios to maximize ADG as well as to minimize SUN levels were 0.67 and 0.65, respectively, using a linear broken-line model and 0.72 and 0.71, respectively, using a quadratic model. In Exp. 3 (71 to 92 kg), ADG increased (linear, = 0.007; quadratic, = 0.022) and SUN decreased (linear, = 0.011; quadratic, = 0.034) as the dietary SID Val:Lys ratio increased. The SID Val:Lys ratios to maximize ADG as well as to minimize SUN levels were 0.67 and 0.67, respectively, using a linear broken-line model and 0.72 and 0.74, respectively, using a quadratic model. In Exp. 4 (94 to 119 kg), ADG increased (linear, = 0.041) and G:F was improved (linear, = 0.004; quadratic, = 0.005) as the dietary SID Val:Lys ratio increased. The SID Val:Lys ratio to maximize G:F was 0.68 using a linear broken-line model and 0.72 using a quadratic model. Carcass traits and muscle quality were not influenced by SID Val:Lys ratio. In conclusion, the dietary SID Val:Lys ratios required for 26- to 46-, 49- to 70-, 71- to 92-, and 94- to 119-kg pigs were estimated to be 0.62, 0.66, 0.67, and 0.68, respectively, using a linear broken-line model and 0.71, 0.72, 0.73, and 0.72, respectively, using a quadratic model.

The antimicrobial peptide sublancin ameliorates necrotic enteritis induced by Clostridium perfringens in broilers.

Sublancin is an antimicrobial peptide produced by 168 containing 37 amino acids. The objective of this study was to investigate its inhibitory efficacy against both in vitro and in vivo. In the in vitro study, we determined that sublancin had a minimum inhibitory concentration of 8 µM against , which was much higher than the antibiotic lincomycin (0.281 µM). Scanning electron microscopy showed that sublancin damaged the morphology of . The in vivo study was conducted on broilers for a 28-d period using a completely randomized design. A total of 252 chickens at 1 d of age were randomly assigned to 1 of 6 treatments including an uninfected control; an infected control; 3 infected groups supplemented with sublancin at 2.88, 5.76, or 11.52 mg activity/L of water; and an infected group supplemented with lincomycin at 75 mg activity/L of water (positive control). Necrotic enteritis was induced in the broilers by oral inoculation of on d 15 through 21. Thereafter, the sublancin or lincomycin were administered fresh daily for a period of 7 days. The challenge resulted in a significant decrease in ADG ( < 0.05) and a remarkable deterioration in G:F ( < 0.05) during d 15 to 21 of the experiment. There was a sharp increase of numbers in the cecum ( < 0.05). The addition of sublancin or lincomycin reduced caecal counts ( < 0.05). The counts had a tendency to decrease in the lincomycin treatment ( = 0.051) but were the highest in the sublancin treatment (5.76 mg activity/L of water). A higher villus height to crypt depth ratio in the duodenum and jejunum as well as a higher villus height in the duodenum were observed in broilers treated with sublancin or lincomycin ( < 0.05) compared with infected control broilers. It was observed that sublancin and lincomycin decreased IL-1ß, IL-6, and tumor necrosis factor-α levels ( < 0.05) in the ileum compared with the infected control. In conclusion, although sublancin's minimum inhibitory concentration is much higher than lincomycin in vitro, less sublancin is needed to control necrotic enteritis induced by in vivo than lincomycin. These novel findings indicate that sublancin could be used as a potential antimicrobial agent to control necrotic enteritis.

The appropriate standardized ileal digestible tryptophan to lysine ratio improves pig performance and regulates hormones and muscular amino acid transporters in late finishing gilts fed low-protein diets.

This study investigated the effects of various standardized ileal digestible (SID) Trp to Lys ratios on the performance and carcass characteristics of late finishing gilts receiving low-CP (9.6%) diets supplemented with crystalline AA. Ninety gilts (89.1 ± 5.1 kg) were used in a dose-response study conducted for 35 d. Crystalline Trp (0, 0.1, 0.2, 0.4, or 0.6 g/kg) was added to a corn-wheat bran basal diet providing SID Trp to Lys ratios of 0.12, 0.15, 0.18, 0.21, or 0.24. Each diet was fed to 6 pens of pigs with 3 gilts per pen. At the end of the experiment, 30 gilts (1 pig per pen) were slaughtered to evaluate carcass traits and meat quality (BW = 121 kg). Increasing the SID Trp to Lys ratio increased ADG (linear and quadratic effect, < 0.05) and also improved G:F (linear and quadratic effect, < 0.05). Serum urea nitrogen (SUN) decreased as the SID Trp to Lys ratio increased (linear and quadratic effects, < 0.05). A quadratic effect of L* light and marbling in the longissimus dorsi was observed as the dietary SID Trp to Lys ratio increased ( < 0.05). Increasing the SID Trp to Lys ratio increased the level of serum GH (quadratic effect, < 0.05) and also increased the level of serum IGF-1 (linear and quadratic effect, < 0.05). Increasing the SID Trp to Lys ratio increased the protein abundance of the muscular AA transporter of sodium-coupled neutral amino acid transporter 2 (SNAT2) in the longissimus dorsi muscle (linear and quadratic effect, < 0.05). The optimum SID Trp to Lys ratios to maximize ADG and G:F as well as to minimize SUN levels were 0.16, 0.17, and 0.16 using a linear-breakpoint model and 0.20, 0.20, and 0.20 using a quadratic model. Tryptophan could influence serum GH and IGF-1 secretion and protein abundance of the muscular AA transporter of SNAT2 in the longissimus dorsi muscle in late finishing gilts fed low-protein diets.

Dietary supplementation with Lactobacillus fermentum I5007 improves the anti-oxidative activity of weanling piglets challenged with diquat.

AIMS: To determine the effects of Lactobacillus fermentum I5007 on the redox state of piglets oxidatively stressed with diquat. METHODS AND RESULTS: Twenty-four, 28-day-old barrows were used in a 2 × 2 factorial design experiment with the main effects being Lact. fermentum supplementation and diquat challenge. Half of the pigs (n = 12) were orally administered with 20 ml of a solution containing 10(8 ) CFU ml(-1) of Lact. fermentum each morning of the 21-day trial, while the remainder received saline. On day 8, these two groups were further subdivided so that half of the pigs in each group (n = 6) were intraperitoneally injected with 10 mg kg(-1) BW diquat, while the remainder received saline. The diquat-injected pigs had significantly poorer performance and increased levels of plasma cortisol, adrenaline, carbonyl and malondialdehyde. Lactobacillus fermentum supplementation significantly increased superoxide dismutase and glutathione and increased the ability to inhibit superoxide anion production in liver and muscle. CONCLUSIONS: Lactobacillus fermentum improved the anti-oxidative defence system and alleviated damage caused by diquat. SIGNIFICANCE AND IMPACT OF THE STUDY: Lactobacillus fermentum has the potential to alleviate oxidative stress and improve weaning pig performance.

Butyrate promotes the recovering of intestinal wound healing through its positive effect on the tight junctions.

Postweaning diarrhea is one of the most common causes of morbidity and mortality in weanling piglets. Feeding sodium butyrate to weanling piglets decreased the incidence of diarrhea, but the mechanism has not been fully elucidated. The present study was to evaluate the effect of sodium butyrate on diarrhea in relation to wound healing of intestinal barrier using IPEC-J2 cell model. Cultured cells were scratched to induce wound and then were treated with 4 mM sodium butyrate. The results showed that supplementation of the cells with sodium butyrate significantly promoted the process of wound healing, indicating the protective effects of butyrate on the intestinal mucosa. Butyrate treatment enhanced mRNA expression of the intestinal mucosal tight junction proteins occludin and zonula occluden protein-1 (P < 0.05), which suggested that the promotion of wound healing by butyrate is related to the maintenance of the function of the intestinal barrier. In addition, in the butyrate-treated group, intestinal total superoxide dismutase and glutathione peroxidase (P < 0.05), two of the main antioxidant enzymes, as well as glutathione (P < 0.05), one of the nonenzymatic antioxidant components, were enhanced whereas the malondialdehyde level, a marker of free radical mediated lipid peroxidation injury, was decreased (P < 0.05) compared with the control group. Collectively, these results indicate that dietary sodium butyrate might, at least partly, play an important role in recovering the intestinal tight junctions having a positive effect on maintaining the gut integrity.

Free radical scavenging activity of Lactobacillus fermentum in vitro and its antioxidative effect on growing-finishing pigs.

AIMS: To evaluate the free radical-scavenging capacity of Lactobacillus fermentum and its effects on antioxidant enzyme levels in finishing pigs. METHODS AND RESULTS: The free radical-scavenging activity of Lact. fermentum was analysed in vitro. The tested Lactobacillus showed a high scavenging ability against DPPH (1,1-diphenyl-2-picrylhydrazyl), superoxide and hydroxyl radicals which was dose dependent. Subsequently, 108 crossbred pigs weighing 20.67 BW, were allotted to dietary treatments including a basal diet or the basal diet supplemented with either aureomycin or 10.2 x 10(7) Lact. fermentum CFU g(-1) diet. Supplementation of Lact. fermentum increased total antioxidant capacity (P < 0.01) in serum from 50 kg pigs, while serum superoxide dismutase (P = 0.01) and glutathione peroxidase (P < 0.01) increased, and malondialdehyde levels decreased (P < 0.01) in 90 kg pigs. Hepatic catalase (P = 0.04), muscle superoxide dismutase (P < 0.01) and copper-zinc-superoxide dismutase were enhanced (P = 0.01), whereas malondialdehyde levels were reduced (P = 0.05) by Lact. fermentum. CONCLUSIONS: The free radical-scavenging capacity of Lact. fermentum was dose dependent and its supplementation improved the antioxidant status of pigs. SIGNIFICANCE AND IMPACT OF THE STUDY: Lactobacillus fermentum could be used to alleviate oxidative stress and increase pig performance and improve pork quality.

Bioefficacy of L-lysine.H2SO4 relative to L-lysine.HCl in broiler chickens, estimated by slope-ratio model.

1. A broiler experiment was conducted to assess the effectiveness of L-lysine.H2SO4 relative to L-lysine.HCl. Four concentrations of L-lysine.H2SO4 and L-lysine.HCl (0.9, 1.8, 2.7 and 3.6 g/kg diet) were each added to a basal diet that met the nutrient requirements of broilers except for lysine. 2. Birds responded significantly to the supplements in daily gain, feed intake, feed conversion efficiency, nitrogen retention and plasma urea nitrogen during each period (d 4 to 21, d 22 to 42 and d 4 to 42). 3. Regression analysis showed that the bioefficacy of L-lysine.H2SO4 relative to L-lysine.HCl was 0.93, 0.86 and 0.95 for daily gain, feed conversion efficiency and nitrogen retention, respectively, during the starter period (d 4 to 21), and was 1.01, 1.36 and 1.06, respectively, during the grower period (d 22 to 42). It was 0.99, 1.07 and 1.03, respectively, for the overall period (d 4 to 42), when the bioefficacy of L-lysine.HCl was set at 1.0. 4. The bioefficacy of L-lysine.H2SO4 differed with different response criteria. The average bioavailability of L-lysine.H2SO4 relative to L-lysine.HCl was 1.03 on an equimolar basis in the present study. In conclusion, L-lysine.H2SO4 and L-lysine.HCl are equally efficacious to broiler chickens.

Effects of enzyme supplementation on performance, nutrient digestibility, gastrointestinal morphology, and volatile fatty acid profiles in the hindgut of broilers fed wheat-based diets.

A growth trial and a metabolism trial were conducted as 2 experiments to investigate the effects of dietary enzyme supplementation (primarily xylanase and beta-glucanase) on performance, nutrient digestibility, intestinal morphology, digestive organ size, and volatile fatty acid profiles in the hindgut of broiler chickens fed wheat-based diets. The experimental diets in both trials consisted of a wheat-based control diet supplemented with 0, 200, 400, 600, 800, or 1,000 mg/kg enzyme. Diets were given to the birds from d 7 to 42 of age. In the growth trial, enzyme supplementation improved performance of the broilers; daily gain and feed conversion increased linearly (P < 0.01) with increasing levels of enzyme supplementation. Enzyme inclusion decreased the size of the digestive organs and the gastrointestinal tract to some extent. The relative length of each intestinal segment decreased linearly (P < 0.05). The relative weight of the anterior intestine on d 21 and ileum on d 42 also decreased linearly (P < 0.01). On d 21 and 42, there were negative linear (P < 0.05) relationships between increasing enzyme supplementation and the relative weight of the liver and pancreas, respectively. Furthermore, there was a linear (P < 0.01) increase in total volatile fatty acid content in ileum on d 21 and in the cecum on d 21 and 42. During each period of the metabolism trial, apparent crude protein digestibility increased linearly (P < 0.05), whereas no differences were detected (P > 0.05) in AME.

[Studies on the active polysaccharides from Lycium barbarum L].

AIM: To investigate the structures and immunomodulation activity of four homogeneous polysaccharides: LBP 1a-1, LBP 1a-2, LBP 3a-1 and LBP 3a-2 isolated from Lycium barbarum L. brought from Zhongning County, Ningxia Province. METHODS: Their molecular weights, sugar component (constituents) and their linkages were determined by gel permeation chromatography, acid hydrolysis, periodate oxidation and NMR spectrum. The activity of immunomodulation was evaluated with splenocyte proliferation by [3H]-TDR incorperation, in vitro. RESULTS: Four polysaccharides with molecular weights 11.5 x 10(4), 9.4 x 10(4), 10.3 x 10(4) and 8.2 x 10(4), were shown to enhance splenocyte proliferation induced by ConA. LBP 1a-1 and LBP 1a-2 were alpha-(1-->6)-D-glucans. LBP 3a-1 and LBP 3a-2 were found to be a-(1-->4)-D-polygalacturonans. CONCLUSION: The four polysaccharides were first isolated from this plant. Polysaccharides with main chain of alpha-(1-->4)-D-polygalacturonans showed stronger immunomodulation activity.