Yueping Chen

Effects of dietary concentrations of methionine on growth performance and oxidative status of broiler chickens with different hatching weight

1. A study was conducted to evaluate the effects of two hatching weight (HW) levels and two dietary concentrations of methionine on the growth performance and oxidative status of broilers. Male Arbor Acres chickens were divided into two groups on their HW (low and high HW, H and L). Each HW group was then distributed into two subgroups, of similar HW, receiving either low or high dietary concentrations of methionine (4.9 g methionine/kg, LM; 5.9 g methionine/kg, HM). Thus, all day-old birds were distributed into 4 treatments (H-LM, H-HM, L-LM, L-HM) × 6 replicates × 10 birds for 21 d. 2. Broilers with high HW were heavier than those with low HW during the 21 d assay, which appeared to result from increased body weight gain rather than improved feed conversion efficiency. A higher dietary concentration of methionine (5.9 g/kg) improved growth performance of broilers with low HW in terms of body weight gain and feed conversion ratio. 3. Broilers with different HW had similar antioxidant status both in serum and liver. 4. Broilers given a diet containing 5.9 g/kg methionine had enhanced serum superoxide dismutase (SOD) activity and decreased hepatic malondialdehyde (MDA) content at day 7. 5. Broilers given a diet containing 5.9 g/kg methionine had a higher hepatic reduced glutathione (GSH):glutathione disulphide (GSSG) ratio than those given a diet containing 4.9 g/kg methionine at day 21. High dietary methionine concentration reduced hepatic GSH content and glutathione peroxidase (GPX) activity of broilers with high HW at day 7 and at day 21, respectively, but increased hepatic GSH content of broilers with low HW at day 7. 6. Although broilers with different HW had similar oxidative status as indicated by several parameters in blood and liver, HW can have positive effects on the subsequent growth performance of broilers, and a higher dietary methionine concentration (5.9 g/kg) can improve growth performance and antioxidant status in broilers exhibiting low HW.

Bacillus amyloliquefaciens supplementation alleviates immunological stress in lipopolysaccharide-challenged broilers at early age

This study was conducted to investigate the effect of Bacillus amyloliquefaciens ( BA: ) on the immune function of broilers challenged with lipopolysaccharide ( LPS: ). 192 one-day-old male Arbor Acre broiler chickens were randomly distributed into four treatments: 1) broilers fed a basal diet; 2) broilers fed a basal diet supplemented with BA; 3) LPS-challenged broilers fed a basal diet; and 4) LPS-challenged broilers fed a basal diet supplemented with BA. Each treatment consisted of six replicates with eight broilers per replicate. Broilers were intraperitoneally injected with either 500 μg LPS per kg body weight or sterile saline at 16, 18 and 20 d of age. LPS decreased the average daily gain ( ADG: , P = 0.001) and average daily feed intake (P = 0.001). The decreased ADG (P = 0.009) and increased feed conversion ratio (P = 0.047) in LPS-challenged broilers were alleviated by BA. LPS increased the relative spleen weight (P = 0.001). Relative spleen (P = 0.014) and bursa (P = 0.024) weights in the LPS-challenged broilers were reduced by BA. LPS increased white blood cell ( WBC: ) numbers (P = 0.001). However, the WBC numbers (P = 0.042) and the ratio of lymphocytes to WBC (P = 0.020) in LPS-challenged broilers were decreased with BA treatment. LPS decreased plasma lysozyme activity (P = 0.001), but increased concentrations of plasma corticosterone (P = 0.012) and IL-2 (P = 0.020). In contrast, BA increased lysozyme activity in plasma (P = 0.040). LPS increased mRNA abundances of splenic toll-like receptor 4 (P = 0.046), interferon γ (P = 0.008), IL-1β (P = 0.045) and IL-6, (P = 0.006). IL-2 (P = 0.014) and IL-6 (P = 0.074) mRNA abundances in LPS-challenged broilers were reduced by BA, although BA had an opposite effect for IL-10 mRNA expression in those broilers (P = 0.004). In conclusion, BA supplementation could partially alleviate the compromised growth performance and immune status of broilers under immune stress induced by LPS challenge at early age.

Methionine improves breast muscle growth and alters myogenic gene expression in broilers

To investigate the mechanism underlying the regulatory effect of Met on broiler growth, the growth performance, organ development, serum profile, myogenic gene expression, and methylation of myostatin gene exon 1 region in response to dietary Met status were evaluated. A total of 192 one-day-old Arbor Acres broiler chicks were housed in 3-layer cages in a temperature-controlled room with continuous lighting. The temperature of the room was maintained at 32 to 34°C for the first 3 d and then reduced by 2 to 3°C per week to a final temperature of 20°C. Cages were randomly allocated to 2 dietary treatments with 6 replicate cages (8 males and 8 females/cage) per treatment. Control starter and finisher diets contained 0.50 and 0.43% Met, respectively. Corresponding values for a +Met treatment were 0.60 and 0.53% Met, respectively. The birds receiving the +Met diets had a greater (P < 0.05) G:F throughout the experiment. The +Met diets increased (P < 0.05) the relative weight of breast muscle and the concentrations of uric acid and triglyceride in serum at 42 d of age, whereas other serum measurements were not affected by treatments. Increased myogenic factor 5 (Myf5) and myocyte enhancer factor 2B (MEF2B) and decreased myostatin mRNA expression were observed in broilers fed the +Met diets (P < 0.05). However, methylation of myostatin gene exon 1 region was not different between groups. In conclusion, broilers fed the +Met diets increased breast muscle growth that was reflected in the expected expression of myostatin, Myf5, and MEF2B genes.

Effects of threonine supplementation on the growth performance, immunity, oxidative status, intestinal integrity, and barrier function of broilers at the early age

&NA; The aim of this study was to investigate effects of L‐threonine (L‐Thr) supplementation on the growth performance, immunity, antioxidant status, and intestinal health of broilers at the early age. One hundred and forty‐four 1‐day‐old male broiler chicks (Arbor Acres Plus) were allocated into 3 treatments with 6 replicates of 8 birds each, and fed a basal diet (analyzed Thr content, 7.87 g/kg) supplemented with 0 (control diet), 1 and 3 g/kg L‐Thr for 21 d, respectively. Treatments did not alter growth performance of broilers. Compared with control, 1 g/kg Thr supplementation increased relative weight of spleen (P = 0.013). A higher level of Thr (3 g/kg) increased relative weight of thymus (P = 0.003). The supplementation of 3 g/kg Thr reduced Escherichia coli (P = 0.040) and Salmonella colonies (P = 0.015), whereas increased Lactobacillus colonies (P < 0.001) in the cecal contents. Thr supplementation increased intestinal villus height (P < 0.05), and the ratio of villus height to crypt depth (P < 0.001), and the values for these parameters were intermediate with 1 g/kg Thr. Goblet cell density was increased by Thr supplementation (P < 0.001). The jejunal immunoglobulin G content was increased by the inclusion of Thr (P = 0.002). Broilers fed diet supplemented with 1 g/kg Thr exhibited increased concentrations of jejunal immunoglobulin M (P = 0.037) and secretory immunoglobulin A (P = 0.018). Likewise, 3 g/kg Thr inclusion increased ileal secretory immunoglobulin A content (P = 0.023). The jejunal malondialdehyde accumulation was reduced by Thr inclusion (P = 0.012). A higher level of Thr inclusion also reduced malondialdehyde content in the serum (P = 0.029). The high level of Thr inclusion (3 g/kg) upregulated mucin‐2 mRNA expression (P = 0.034), whereas downregulated the mRNA abundances of interferon‐&ggr; (P = 0.036) and interleukin‐1&bgr; (P = 0.031) in the ileum. In conclusion, L‐Thr supplementation can improve immunity, antioxidant capacity, and intestinal health of broilers at an early age.

An evaluation of zinc bearing palygorskite inclusion on the growth performance, mineral content, meat quality, and antioxidant status of broilers

The current study was conducted to investigate the effect of zinc (Zn) bearing palygorskite (ZnPal) inclusion on the growth performance, mineral content, meat quality, and antioxidant status of broilers. A total of 240 one-day-old Arbor Acres broiler chicks were randomly allocated into 5 dietary treatments with 6 replicates of 8 chicks. Broilers in the 5 treatments were fed a basal diet supplemented with 0, 20, 40, 60, and 80 mg/kg Zn diet in the form of ZnPal for 42 d, respectively. Birds exhibited similar average daily gain (ADG), average daily feed intake (ADFI), and feed/gain ratio (F:G) among groups during the 42-day study (P>0.05). ZnPal supplementation linearly increased iron (Fe) (P=0.031) and magnesium (Mg) (P=0.002) content in the pectoralis major muscle. Similarly, the inclusion of ZnPal tended to increase Zn content in the thigh (P=0.072) and linearly increase Zn content in the pectoralis major muscle (P=0.055). The concentration of copper (Cu) in the thigh was linearly decreased by ZnPal inclusion (P=0.011). Meanwhile, a quadratic trend for reduced Cu content was observed in the pectoralis major muscle (P=0.074) and thigh (P=0.082), respectively. The supplementation of ZnPal linearly reduced cooking loss in the pectoralis major muscle (P=0.013), and linearly (P=0.029) and quadratically (P=0.034) decreased cooking loss in the thigh. Malondialdehyde (MDA) concentration in the thigh was linearly (P=0.020) and quadratically (P=0.017) reduced by ZnPal inclusion. Additionally, ZnPal supplementation tended to linearly enhance total antioxidant capacity (T-AOC) activity of the pectoralis major muscle (P=0.083). The results obtained in the current study indicated that ZnPal inclusion could alter muscular mineral accumulation, improve meat quality, and enhance the muscular antioxidant capacity of broilers, and Zn supplementation in the form of ZnPal at the dosage of 20 mg/kg would be sufficient in improving meat quality and muscular oxidative status.

Effects of synbiotic supplementation on growth performance, carcass characteristics, meat quality and muscular antioxidant capacity and mineral contents in broilers

BACKGROUND The present study aimed to investigate the effects of dietary synbiotic supplementation on growth performance, carcass composition, meat quality and muscular antioxidant capacity, and mineral contents in broilers. Accordingly, 96 day-old male broiler chicks (Arbor Acres Plus; Aviagen, Huntsville, AL, USA) were randomly allocated to two groups, and each group consisted of six replicates with eight chicks each. Birds were fed a corn-soybean meal basal diet supplemented with either 0 or 1.5 g kg-1 synbiotic, consisting of probiotics (Bacillus subtilis, Bacillus licheniformis and Clostridium butyricum) and prebiotics (yeast cell wall and xylooligosaccharide) from 1 to 42 days of age. RESULTS Compared with the control group, supplementation with a synbiotic increased average daily gain (P < 0.05) but reduced feed/gain ratio (P < 0.01) in broilers from 1 to 42 days of age. Similalrly, dietary synbiotic inclusion increased breast yield (P < 0.05) but decreased abdominal fat (P < 0.01) in broilers. The breast muscle pH value at 24 h postmortem in broilers was elevated with the incorporation of synbiotic (P < 0.05). By contrast, synbiotic supplementation lowered the cooking loss during heat treatment in a water bath, malondialdehyde content, and total Cr content in the thigh muscle in broilers (P < 0.05). CONCLUSION Dietary synbiotic supplementation into the diet of broilers may be an effective method for improving growth performance and carcass compositions, resulting in the production of meat with a favorable quality and oxidative stability.

Zinc‐bearing zeolite clinoptilolite improves tissue zinc accumulation in laying hens by enhancing zinc transporter gene mRNA abundance

A study was conducted to investigate effects of zinc-bearing zeolite clinoptilolite (ZnCP), as an alternative for zinc sulfate (ZnSO4), on laying performance, tissue Zn accumulation and Zn transporter genes expression in laying hens. Hy-Line Brown laying hens were allocated to three treatments, each of which had six replicates with 15 hens per replicate, receiving basal diet supplemented with ZnSO4 (control, 80 mg Zn/kg diet), 0.23% ZnCP (40.25 mg Zn/kg diet) and 0.46% ZnCP (80.50 mg Zn/kg diet) for 8 weeks, respectively. Compared with control, hens fed diet containing 0.23% ZnCP had similar Zn content in measured tissues (P > 0.05). A higher ZnCP inclusion (0.46%) enhanced Zn accumulation in liver (P < 0.05) and pancreas (P < 0.05). In addition, ZnCP inclusion increased blood iron (Fe) content (P < 0.05). ZnCP supplementation enhanced jejunal metallothionein-4 (MT-4) messenger RNA (mRNA) abundance (P < 0.05). ZnCP inclusion at a higher level (0.46%) increased mRNA expression of MT-4 in pancreas (P < 0.05) and zinc transporter-1 (ZnT-1) in jejunum (P < 0.05). The highest ZnT-2 mRNA abundance in jejunum was found in hens fed 0.23% ZnCP inclusion diet (P < 0.05). The results indicated that ZnCP reached a higher bioavailability as compared with ZnSO4 as evidenced by enhanced tissue Zn accumulation and Zn transporter genes expression.

MSTN, mTOR and FoxO4 Are Involved in the Enhancement of Breast Muscle Growth by Methionine in Broilers with Lower Hatching Weight

Broilers with lower hatching weight (HW) present poorer performance than those with high HW, but there is limited research on the growth regulation of broilers with lower HW. The objective of this study was to investigate the effect of dietary methionine (Met) levels on the growth performance and breast muscle yield of broilers with different HW and underlying mechanisms. A total of 192 one-day-old Arbor Acres broiler chicks with different HW (heavy: 48.3±0.1 g, and light: 41.7±0.1 g) were allocated to a 2×2 factorial arrangement with 6 replicates of 8 chicks per replicate cage. Control starter (1–21 d) and finisher (22–42 d) diets were formulated to contain 0.50% and 0.43% Met, respectively. Corresponding values for a high Met treatment were 0.60% and 0.53%. Light chicks had lower body weight gain (BWG) and breast muscle yield than heavy chicks when the broilers were fed the control diets. High Met diets improved BWG, gain to feed ratio and breast muscle yield in light but not heavy chicks. Decreased DNA content and increased RNA/DNA and protein/DNA ratios in breast muscle were induced by high Met diets only in light chicks. MSTN mRNA level was decreased by high Met diets only in light chicks, and this decrease was accompanied by a significant increase in MSTN gene exon 1 methylation. In addition, high Met diets increased mTOR phosphorylation, but decreased FoxO4 phosphorylation in breast muscle of light chicks. In conclusion, the BWG and breast muscle yield of light chicks were improved by increasing dietary Met levels probably through alterations of MSTN transcription and phosphorylation of mTOR and FoxO4.

Effects of Heat-oxidized Soy Protein Isolate on Growth Performance and Digestive Function of Broiler Chickens at Early Age

This study was conducted to investigate effects of heat-oxidized soy protein isolate (HSPI) on growth performance, serum biochemical indices, apparent nutrient digestibility and digestive function of broiler chickens. A total of 320 1-day-old Arbor Acres chicks were randomly divided into 4 groups with 8 replicates of 10 birds, receiving diets containing soy protein isolate (SPI, control group) or the same amount of SPI heated in an oven at 100°C for 1, 4, or 8 h, for 21 days, respectively. The results indicated that compared with the control group, body weight gain and feed intake of birds fed diet containing SPI heated for 8 h were significantly lower (p<0.05). Serum urea nitrogen concentration was higher in the broilers fed diet containing SPI heated for 4 or 8 h at d 21 (p<0.05). In contrast, serum glucose content was decreased by HSPI substitution at d 21 (p<0.05). The relative pancreas weight in HSPI groups was higher than that in the control group at d 21 (p<0.05). Meanwhile, the opposite effect was observed for relative weight of anterior intestine and ileum in broilers fed a diet containing SPI heated for 8 h (p<0.05). Birds fed diets containing SPI heated for 4 or 8 h had a decreased lipase activity in anterior intestinal content at d 14 and 21 (p<0.05), respectively. In addition, the same effect was also noted in broilers given diets containing SPI heated for 1 h at d 21 (p<0.05). Similarly, amylase, protease and trypsin activity in anterior intestinal content were lower in broilers fed diets containing SPI heated for 8 h at d 21 (p<0.05). The apparent digestibility of dry matter (DM) from d 8 to 10 and DM, crude protein (CP), and ether extract from d 15 to 17 were lower in broilers fed diets containing SPI heated for 8 h (p<0.05). Besides, birds given diets containing SPI heated for 4 h also exhibited lower CP apparent digestibility from d 15 to 17 (p<0.05). It was concluded that HSPI inclusion can exert a negative influence on the growth performance of broilers, which was likely to result from the simultaneously compromised digestive function.

Effects of Dietary Zinc Bearing Palygorskite Supplementation on the Carcass Traits, Chemical Composition of Muscle, and Muscular Lead and Chromium Contents of Broilers

The present study was conducted to investigate the effects of zinc (Zn) bearing palygorskite (ZnPal) inclusion on the carcass traits, chemical composition of muscle, and muscular lead (Pb) and chromium (Cr) contents of broilers. A total of 240 1-day-old Arbor Acres broiler chicks were randomly divided into 5 dietary treatments with 6 replicates of 8 chicks each. Broilers in the 5 treatments were fed a basal diet supplemented with 0 (Control group), 20, 40, 60, and 80 mg/kg Zn in the form of ZnPal for 42 days, respectively. There were no differences in the carcass yield, abdominal fat yield, subcutaneous fat thickness, and intramuscular fat width among treatments (P>0.05). Compared with the control group, the eviscerated yield (P=0.010) and thigh muscle yield (P=0.046) were quadratically increased by the supplementation of ZnPal (P<0.05). Similarly, the breast muscle yield was linearly (P=0.024) and quadratically (P=0.011) increased by ZnPal inclusion. The addition of ZnPal to diets of broilers also linearly (P=0.002) increased fat content in the thigh. Moreover, the supplementation of ZnPal linearly and quadratically reduced the content of muscular Pb and the content of Cr in the thigh muscle (P<0.05). It was concluded that ZnPal inclusion could improve carcass traits, increase fat content in the thigh, and reduce the accumulations of Pb and Cr in the muscles, and this effect was more pronounced when extra Zn dosage in the form of ZnPal was 40 mg/kg.