As the first limiting amino acid, lysine (Lys) has been thought to promote muscle fiber hypertrophy by increasing protein synthesis. However, the functions of Lys seem far more complex than that. Despite the fact that satellite cells (SCs) play an important role in skeletal muscle growth, the communication between Lys and SCs remains unclear. In this study, we investigated whether SCs participate directly in Lys-induced skeletal muscle growth and whether the mammalian target of rapamycin complex 1 (mTORC1) pathway was activated both in vivo and in vitro to mediate SC functions in response to Lys supplementation. Subsequently, the skeletal muscle growth of piglets was controlled by dietary Lys supplementation. Isobaric tag for relative and absolute quantitation (iTRAQ) analysis showed activated SCs were required for longissimus dorsi muscle growth, and this effect was accompanied by mTORC1 pathway upregulation. Furthermore, SC proliferation was governed by medium Lys concentrations, and the mTORC1 pathway was significantly enhanced in vitro. After verifying that rapamycin inhibits the mTORC1 pathway and suppresses SC proliferation, we conclude that Lys is not only a molecular building block for protein synthesis but also a signal that activates SCs to manipulate muscle growth via the mTORC1 pathway.

The experiment was conducted to investigate the effects of bilberry extract on growth performance, meat quality, antioxidant status, and immune function of yellow-feathered chickens. A total of 360 female hatchling Lingnan chickens were randomly allocated to three treatments with 6 replicates of 20 chickens per replicate. Birds were fed a basal diet supplemented with 0 (the control group), 100 (B100), and 400 (B400) mg/kg of bilberry extract for 63 d. Compared with the controls, (1) dietary supplementation with bilberry extract did not affect the growth performance of chickens from 1 to 63 d. (2) At 21 d, the relative weight of the bursa of Fabricius was increased (p < 0.05) by dietary supplementation with 400 mg/kg bilberry extract. Bilberry extract decreased the concentrations of IgY and IgM in blood plasma of 63-d chickens (p < 0.05). (3) For 21-d chickens, dietary supplementation with 400 mg/kg bilberry extract increased (p < 0.05) the activity of GSH-Px in blood plasma and jejunal mucosa (p < 0.05). Supplementation with 100 mg/kg bilberry extract increased (p < 0.05) the activities of T-SOD in jejunal mucosa and GSH-Px in the liver and decreased (p < 0.05) the MDA concentration in the liver. For chickens at the age of 63 d, both levels of bilberry extract increased activity of T-SOD in blood plasma (p < 0.05) and reduced MDA concentration in the jejunum (p < 0.05). (4) Supplementation with bilberry extract in the diet decreased the MDA concentration (B100) in muscle of 63-d chickens at 45 min postmortem and increased (p < 0.05) the activity of T-SOD (B400) at 4 d postmortem. (5) In breast muscle at 63 d, birds supplemented with bilberry extract (B400) had increased pH and drip loss while drip loss was reduced in the B100 treatment (p < 0.05); treatments did not affect inosinic acid or intramuscular fat contents. In conclusion, dietary supplementation of yellow-feathered chickens with bilberry extract enhanced the relative weight of the bursa of Fabricius, and broadly increased activities of antioxidant enzymes; indices of meat quality were improved without impact on growth performance. Considering the results in the current research, 100 mg/kg bilberry extract was recommended when supplemented in chickens.

This study was conducted to evaluate the effects of acidifier (benzoic acid, BA), amylase (AL) and their combination as substitutes for antibiotics on growth performance, antioxidation, nutrient digestion and gut microbiota of yellow-feathered broilers. A total of 1440 twenty-one-day-old broilers were randomly allocated to six treatments. Broilers in the control group (CON) were fed a basal diet, whereas birds in the other five groups were fed the basal diet supplemented with antibiotic (zinc bacitracin, AT, 40 mg/kg), BA (2000 mg/kg), low level AL (AL-L, 300 mg/kg), high level AL (AL-H, 500 mg/kg) and the combination of AL-H and BA (BA+AL-H). The experimental animals were killed at the end of the trial (21 day-63 day) then blood samples were collected from two birds per pen. Bird weight, feed intake and survival rate were recorded on pen basis. Growth performance was not significantly influenced by AT, BA, AL-L, AL-H or BA+AL-H. Plasma uric acid (UA) was decreased from CON by all treatments; the activity of AKP in plasma was also lowered by AT, BA, AL-H and BA+AL-H. Plasma activity of LDH was reduced by BA. In the jejunal mucosa, Na⁺K⁺-ATP activity was increased by BA, AL-L, AL-H and BA+AL-H. Mucosal activities of T-AOC and CAT were increased with AL-L and AT supplementation, respectively. Additionally, the relative abundance of Escherichia coli (E. coli) in the cecal contents was reduced by BA+AL-H and, with the exception of AL-H, all treatments increased the relative abundance of Lactobacillus. In conclusion, dietary AT, BA, AL-L, AL-H or BA+AL were effective in improving the antioxidant capacity, nutrient digestion and gut microbiota composition. No significant differences were observed in the tested variables between AT and other treatments, indicating that BA, AL and their combination may be alternatives to dietary inclusion of zinc bacitracin. Dietary addition of 500 mg/kg AL and 2000 mg/kg BA was an optimum supplementation dose.

This study investigated the protective effects of anthocyanin (AC) supplementation on lipopolysaccharide (LPS)-challenged yellow-feathered broiler chicks. A total of 480 1-d female broiler chicks were randomly assigned to 4 treatment groups: basal diet (CON), basal diet + LPS-challenge (LPS), supplementation with 100 or 400 mg/kg AC + LPS-challenge (AC100, AC400). On d 17 and d 19, birds in LPS, AC100 and AC400 received an intramuscular dose of LPS, while birds in CON received saline. The result showed that (1) LPS injection significantly decreased (P < 0.05) body weight on d 21 and average daily gain of broiler chicks from 1 to 21 days of age, and supplementation with 100 mg/kg AC increased (P < 0.05) those of LPS-challenged broilers. (2) There were no differences among the treatments (P > 0.05) in relative weights of immune organs. (3) Supplementation with AC (AC100 and AC400) increased (P < 0.05) the jejunal villus height and villus height/crypt depth ratio (AC100) of LPS-challenged birds. Challenge with LPS decreased the relative expression of OCLN (Occludin), ZO-1, JAM2, and MUC2 in jejunal mucosa of broilers, and supplementation with AC offset the relative expression of ZO-1, JAM2 (AC100 and AC400), and OCLN (AC400) in LPS-injected broilers. (4) LPS-induced increase in the malondialdehyde (MDA) concentration and decreases in activity of total superoxide dismutase (T-SOD), and expression of SOD1, CAT and GPX in jejunal mucosa, were attenuated by dietary AC supplementation. In conclusion, in yellow-feathered broiler chicks, dietary supplementation with AC alleviated LPS-induced declined growth performance and mucosal damage of the intestine through antioxidant effects.

This study investigated the influence of dietary supplementation with some antibiotic alternatives on growth performance, intestinal barrier, and immunity of lipopolysaccharide (LPS) challenged chicks. Wenshi females, aged 4 days, were allocated randomly into eight groups, each with six replicates of 20 birds (n = 120/treatment), which received a basal diet supplemented with 0 (control), 0 (LPS), 200 mg/kg aureomycin, 50 mg/kg mushroom polysaccharide, 100 mg/kg mushroom polysaccharide, 500 mg/kg nano-copper, 300 mg/kg copper loaded chitosan, and 500 mg/kg lysozyme for 21 days. On day 18 and 20, the control birds were injected with 0.5 mL saline solution, the other treatments were injected with 0.5 mL saline containing 500 µg LPS/kg body weight (BW). The results indicated that LPS treatment reduced the BW, average daily gain (ADG), and daily feed intake (ADFI) than the controls (p < 0.05), and the antibiotic and the tested alternatives could not retrieve the normal BW, ADG, and ADFI. The tested additives reduced several negative effects of LPS; they reduced diamine oxidase activity and inflammatory mediators in plasma, jejunal mucosa, spleen and thymus, increased content of immunoglobulin in plasma and jejunal mucosa, and decreased gene expression of inducible nitric oxide synthase and Cyclooxygenase 2 in jejunal mucosa.

This experiment investigated the effect of an optimized supplemental dietary manganese (Mn) on growth performance, tibial characteristics, immune function and meat quality, of yellow-feathered broilers. In three rearing periods, birds were fed for 21-d periods, from d 1 (starter), d 22 (grower) and d 43 (finisher), respectively, with basal diets (containing 16, 17, and 14 mg/kg analyzed Mn, respectively) supplemented with 0, 20, 40, 60, 80, 100, 120 and 140 mg/kg Mn. For starter phase broilers, supplemental manganese affected feed to gain ratio (F/G), and the minimum value was observed with 120 mg/kg manganese. During the grower phase, ADG increased quadratically (p < 0.05) with supplemental Mn and was maximal with 54 mg/kg additional manganese estimated using the regression equation. There was no influence of supplemental manganese on growth performance of broilers during the finisher phase (p > 0.05). The thymic relative weight of broilers were linearly (p < 0.05) and quadratically (p < 0.05) increased with supplemental Mn and maxima were obtained with 95 and 110 mg/kg additional Mn at 42 d and 63 d. The bone density of the tibia in broilers at d 21, 42 and 63 were increased quadratically (p < 0.05) by supplemental Mn, and optimal supplementation for the three phases was 52, 60 and 68 mg/kg, respectively. The weight, diameter, breaking strength and bone density of the tibia of 63-d broilers were influenced (p < 0.05) by supplemental manganese. The lightness (L*) value (linear, p < 0.05) and yellowness (b*) value (p < 0.05) of the breast muscle were decreased by dietary manganese supplementation, and the optimal supplementation, based on L*, was 86 mg/kg. In conclusion, supplemental Mn affected the growth performance, thymic relative weight, tibial characteristics, and the meat color of yellow-feathered broilers. From the quadratic regressions, the optimal supplementation of yellow-feathered broilers at the starter, grower and finisher phases to achieve the best performance was 52, 60, and 68 mg/kg, respectively.