Effects of corn particle size on growth performance, gastrointestinal development, carcass indices and intestinal microbiota of broilers.

This experiment was conducted to investigate the effects of different corn particle sizes on growth performance, gastrointestinal development, carcass processing yields and intestinal microbiota of caged broilers. One-day-old Ross 308 broilers were randomly divided into 8 treatments with 10 replicates per treatment and 30 birds per replicate pen. The experiment lasted 37 d. Feed and water were provided ad libitum. The results showed as follows: birds fed diets with the FG corn between d 1 and 13 and CG corn between d14 to 37 had increased body weight, daily gain, and feed intake (P < 0.05). Birds fed diets with CG corn between d 24 to 37 had a heavier relative weight of gizzard at d 38 (P < 0.05). Birds fed diets with FG corn from d 1 to 13 and the CG corn from d 14 to 37 had a higher carcass yield and a relative thigh weight at d 38 (P < 0.05). The intestinal microbiota was significantly affected by different corn particle sizes. The relative abundance of Lactobacillaceae was significantly decreased, whereas that of Peptostreptococcaceae was increased (P < 0.05) in birds fed with the CG corn between d1 to 37. The relative abundance of Acinetobacter was significantly increased in birds fed the FG corn between d1 to 37 (P < 0.05). In conclusion, the use of FG corn in the starter phase and CG corn in the grower and finisher phases was beneficial to growth performance, gastrointestinal development and intestinal microbial structure of broilers reared in cages.

Characterization of miRNAs involved in response to poly(I:C) in porcine airway epithelial cells.

MicroRNAs (miRNA) have been implicated in a variety of pathological conditions including infectious diseases. Knowledge of the miRNAs affected by poly(I:C), a synthetic analog of viral double-stranded RNA, in porcine airway epithelial cells (PAECs) contributes to understanding the mechanisms of swine viral respiratory diseases, which bring enormous economic loss worldwide every year. In this study, we used high throughput sequencing to profile miRNA expression in PAECs treated with poly(I:C) as compared to the untreated control. This approach revealed 23 differentially expressed miRNAs (DEMs), five of which have not been implicated in viral infection before. Nineteen of the 23 miRNAs were down-regulated including members of the miR-17-92 cluster, a well-known polycistronic oncomir and extensively involved in viral infection in humans. Target genes of DEMs, predicted using bioinformatic methods and validated by luciferase reporter analysis on two representative DEMs, were significantly enriched in several pathways including transforming growth factor-ß signaling. A large quantity of sequence variations (isomiRs) were found including a substitution at position 5, which was verified to redirect miRNAs to a new spectrum of targets by luciferase reporter assay together with bioinformatics analysis. Twelve novel porcine miRNAs conserved in other species were identified by homology analysis together with cloning verification. Furthermore, the expression analysis revealed the potential importance of three novel miRNAs in porcine immune response to viruses. Overall, our data contribute to clarifying the mechanisms underlying the host immune response against respiratory viruses in pigs, and enriches the repertoire of porcine miRNAs.