Effect of Zinc Amino Acid Complexes on Growth Performance, Tissue Zinc Concentration, and Muscle Development of Broilers.

The present study aimed to evaluate the effects of zinc amino acid complexes on growth performance, tissue zinc concentration, and muscle development in broilers. A total of 504 day-old male arbor acres broilers were randomly divided into seven treatments (fed with a basal diet or a basal diet supplemented with 120 mg kg-1 Zn as ZnSO4, 30, 60, 90 or 120 mg kg-1 Zn as ZnN, or 30 mg kg-1 Zn as ZnA separately). Each group had six replicates, with 12 birds per replicate. The results showed that the addition of 60 mg kg-1 ZnN significantly increased (P < 0.05) the average daily gain (ADG) and breast muscle percentage of broilers. Zinc concentration of ZnN and ZnA added groups were higher than (P < 0.05) that in the Zn sulfate group under the same addition dose. Except for the 30 mg kg-1 ZnN group, the muscle fiber diameter and cross-sectional area (CSA) were significantly increased (P < 0.05) in the ZnN addition groups. Compared with the basal diet group, adding ZnN significantly increased (P < 0.05) the expression of MTOR, MYOD, and MYOG at day 21 and decreased (P < 0.05) the expression of Atrogin-1. The expression levels of AKT, MTOR, P70S6K, and MYOD were increased at day 42, while the expression levels of MuRF1 and Atrogin-1 were decreased. Adhesion, backbone regulation of actin, MAPK, mTOR, and AMPK were significantly enriched as indicated by KEGG pathway enrichment analysis. In conclusion, zinc amino acid complexes could improve growth performance, tissue zinc concentration, and regulate breast muscle development.

Dietary essential oils improves the growth performance, antioxidant properties and intestinal permeability by inhibiting bacterial proliferation, and altering the gut microbiota of yellow-feather broilers.

This experiment was conducted to investigate the antibacterial effects of essential oils (EO) in vitro and the influence of EO on growth performance, intestinal morphology and oxidation resistance and cecal microflora of yellow-feathered broilers. A total of 720 one-day-old male yellow feather broilers were randomly assigned into 4 treatments with 6 replicate cages of 30 broilers each. The groups were as follows: CON group (basal diet), EO200 group (basal diet + 200 mg/kg EO), EO400 group (basal diet + 400 mg/kg EO), and EO600 group (basal diet + 600 mg/kg EO). The experiment lasted for 48 d. Results showed that the growth and biofilm formation of avian pathogenic E. coli O78 and Salmonella pullorum were limited by adding EO to the diet (P < 0.05). Besides, birds fed with EO had greater (P < 0.05) average daily feed intake (ADFI), average daily gain (ADG), and body weight (BW) during d 1 to 21, 22 to 42, and 1 to 48 and lower (P < 0.05) feed: gain (F:G) than those fed with basal diet during d 22 to 42 and 1 to 48. Moreover, the activity of antioxidant enzyme and the intestinal permeability were improved in the EO400 and EO600 groups rather than the CON group on d 21 (P < 0.05). There were significant differences in cecal microbial composition and enrichment of metabolic pathways of birds among all groups by 16S-based sequencing. In summary, some dose of EO improved bacteriostatic ability, antioxidant ability, and intestinal health of broilers which contributed to the growth performance improvement of yellow-feathered broilers, which can be a promising antibiotic alternative for improving poultry production.

Protective effect and possible mechanism of arctiin on broilers challenged by Salmonella pullorum.

This study was aimed to investigate the effects of dietary arctiin (ARC) supplementation (100, 200, and 400 mg/kg) on the growth performance and immune response of broilers after a Salmonella pullorum (S. pullorum) challenge, and we conducted in vitro antibacterial test to explore the bacteriostatic mechanism of ARC. The in vivo trial was randomly assigned to six groups: noninfected control (NC) group and positive control (PC) group received a basal diet; TET group, received a basal diet supplemented with 100 mg/kg chlortetracycline; ARC100, ARC200, and ARC400 groups received a basal diet containing 100, 200, and 400 mg/kg ARC, respectively. From days 14 to 16, all birds (except the NC group) were infected with 1 mL (1 × 108 CFU per mL) fresh S. pullorum culture by oral gavage per day. In vivo results showed that dietary supplementation of 200 mg/kg ARC significantly increased average daily gain (P < 0.05) and decreased feed-to-gain ratio of broilers vs. the PC group during days 15 to 28 after being challenged with S. pullorum (P < 0.05). The jejunal crypt depth (CD) was decreased by supplementing 100 or 200 mg/kg ARC in diets compared with PC birds at day 19 (P < 0.05). The jejunal villi height (VH) was increased by supplementing 100, 200, or 400 mg/kg ARC in diets compared with PC birds at day 28 (P < 0.05). Besides, dietary supplementation of 200 mg/kg ARC increased the jejunal VH to CD ratio than the PC group both at days 19 and 28 (P < 0.05). Notably, the broilers had lower serum lipopolysaccharide and diamine oxidase levels in the ARC100 and ARC200 groups at day 28 than those in the PC group (P < 0.05). Furthermore, in comparison to PC birds, the birds in ARC groups (100, 200, and 400 mg/kg) had higher serum contents of IgM and IL-10, and the birds in the ARC200 group had higher serum contents of IgA at day 19 (P < 0.05). At day 28, the birds in ARC groups (100, 200, and 400 mg/kg) had lower serum contents of IL-8, and the birds in the ARC200 group had lower serum contents of IFN-γ compared with PC birds (P < 0.05). The in vitro experiment showed that ARC significantly inhibited the biofilm formation and adhesion of S. pullorum (P < 0.05). Metabonomics analysis revealed that ARC can restrain the formation of the biofilm by affecting a variety of metabolic pathways of S. pullorum. Therefore, dietary supplementation of 200 mg/kg ARC might be a potential way to substitute antibiotics to control S. pullorum infection in broilers.

Pullorosis caused by Salmonella pullorum (S. pullorum) is a severe contagious disease and could cause great economic loss to the poultry industry. Antibiotics are usually used to control pullorosis, while prolonged use of antibiotics has led to the emergence of multidrug-resistant bacterial strains. Therefore, it is necessary to find safer and more effective alternatives to substitute antibiotics. In this study, we established a model of S. pullorum infection in broilers and conducted in vitro antibacterial test to explore the preventive effect and mechanisms of dietary arctiin (ARC) supplementation on S. pullorum infection in broilers. The results showed that ARC could not only improve the immune function of infected broilers by regulating the immune system but also directly inhibit the invasion of S. pullorum to broilers by inhibiting the formation and adhesion rate of S. pullorum biofilm. Dietary supplementation of 200 mg/kg ARC might be a potential way to substitute antibiotics to control S. pullorum infection in broilers.