Responses of intestinal morphology, immunity, antioxidant status and cecal microbiota to the mixture of glycerol monolaurate and cinnamaldehyde in laying hens.

This study was to determine the effects of the mixture of glycerol monolaurate and cinnamaldehyde (GCM) supplementation on the intestinal morphology, immunity, antioxidant status and cecal microbiota of laying hens. A total of 1,120 healthy laying hens (Jingfen-1 strain) at the age of 14 wk were randomly divided into 4 groups with 10 replicates of 28 layers in each and layers were fed diets containing 0 (control group), or 250, 500, and 1,000 mg/kg GCM for 12 wk. The results showed that dietary supplementation with GCM significantly increased intestinal villus height and villus height/crypt depth, duodenal villus area, total superoxide disumutase activities in the liver and jejunum, jejunal glutathione peroxidase activities while decreased duodenal and jejunal crypt depth, hydrogen peroxide content in the liver and jejunal malondialdehyde content of laying hens aging 28 wk (P < 0.05). Meanwhile, GCM addition significantly increased serum immunoglobulin A and immunoglobulin M concentration of layers at the age of 20, 24, and 28 wk (P < 0.05). Moreover, it was observed in the 16S rRNA sequencing that the addition of GCM elevated the abundance and diversity of gut microbiota in laying hens. The predominant bacteria from each group were Bacteroidota and Firmicutes at the phylum level and Bacteroides and Lactobacillus were the dominant genera. The composition and structure of cecal microflora were changed by the addition of GCM to the diet of laying hens. In conclusion, the addition of GCM (500-1,000 mg/kg diet) can improve intestinal morphology, immune function, intestinal and liver antioxidant status and intestinal flora of laying hens, thereby improving intestinal digestion and absorption capacity. These findings provide a new way to further explore the mechanism of GCM improving intestinal health.

Molecular cloning and characterization of gloverin from the diamondback moth, Plutella xylostella L. and its interaction with bacterial membrane.

Gloverin restricted to Lepidoptera is known to be a glycine-rich and heat stable antimicrobial protein. The current research reports a 650 bp full-length cDNA encoding gloverin from Plutella xylostella (PxGlo) by reverse transcription polymerase chain reaction and rapid amplification of cDNA ends. PxGlo transcript was detected in both developmental stages and several tissues of 4th instar naïve larvae of P. xylostella with higher levels in the fat bodies. The mRNA levels of PxGlo increased appreciably in fat bodies after injection of Escherichia coli K12. The recombinant PxGlo expressed in S2 cells was purified by Anti-V5 M2 agarose beads which showed high activity against E. coli K12, while low activity against Bacillus thuringiensis, Staphylococcus aureus and E. coli D31. The analysis of transmission electron microscope and scan electron microscope showed PxGlo to cause significant morphological alteration in the E. coli K12 cell surface. Knockdown of PxGlo expression by RNAi increased the larval susceptibility towards the pathogenic bacteria i.e., Serratia marcescens and B. thuringiensis. Our results showed that PxGlo is an inducible antibacterial peptide which exhibits high activity mainly against E. coli K12, and PxGlo performs vital roles against the infection of pathogenic bacteria.

Assessment of herbivore performance on host plants.

Two models for assessing the performance of herbivores on a variety of host plants are developed by combining knowledge of population genetics and population ecology, especially that of the fixation probability of mutant genes. The absolute host performance model precisely assesses host performance for one herbivore population based on parameters of fecundity, larval survivorship, and selection pressure. The relative host performance model compares host performance for one population among different host plant species and for several populations on the same host species. Two herbivore populations, Bemisia tabaci (Gennadius) and Tetranychus truncates Ehara, were used to validate the absolute and relative host performance models. Results indicated that the assessment systems of host performance were reasonable and reliable. These models could be applied to a wide range of herbivore species for assessing their performance on host plants.