The effects of dietary supplementation of essential oil on growth performance, carcass yield, meat quality, serum antioxidant capacity, and intestinal tight junctions of broilers with or without Eimeria challenge were investigated. A total of 576 one-day-old male broilers were randomly separated into 8 treatments (6 replication floor-pens per treatment, 12 broilers per pen) in a 4 × 2 factorial design. The 4 diets consisted of 1) a corn and soybean meal basal diet, 2) an anticoccidial diet (60 g nicarbazin and 60 g narasin per ton of feed), 3) an oregano oil diet (500 ppm oregano oil), and 4) a clove oil diet (500 ppm clove oil). On d 10, half chicks were challenged with 1 × 10⁴ sporulated oocysts of E. tenella, E. acervulina, and E. maxima per chick, whereas the others were inoculated with an equal amount of dilution (0.5 mL). The Eimeria challenge induced a higher fecal oocyst output on d 18, a lower duodenum Occludin expression level on d 28, a lower serum catalase level, and a higher cook loss and protein loss in thigh muscle on d 42. The anticoccidial diet lowered fecal Eimeria output and increased d 1 to 42 BW gain as compared to the control diet. The clove oil treatment enhanced duodenum ZO-1 expression level in nonchallenged birds, increased BW gain from d 1 to 14 and breast yield on d 42. The oregano oil treatment enhanced ZO-1 expression of challenged birds, reduced feed intake from 15 to 28 d, and helped broilers gain more tender meat. For those Eimeria-challenged broilers, both clove and oregano oil treatments recovered drip loss in breast muscle. Our results suggested that Eimeria challenge in broiler early age could interrupt later serum antioxidant capacity and damage meat quality. The dietary supplementation of clove or oregano essential oils could improve broiler growth performance and partially relieve the coccidial damage in gut integrity and meat quality.

This work revealed the importance of microbial succession to microbiota structure and metabolites. Multi-inoculations would promote deterministic assembly. It would facilitate the regulation of microbiota structure and metabolic profile. In addition, we established a model to predict final metabolites based on microbial genera related to microbial succession. This model was beneficial for optimizing the inoculation of the microbiota. This work would be helpful for controlling the spontaneous food fermentation and directionally improving the food quality.

The invasion of Eimeria causes damage to the intestinal barrier, nutrient leakage, and microbial imbalance in poultry. We aimed to investigate the effects of Eimeria infection on growth performance, intestinal integrity, and cecal microbial diversity and composition of yellow broilers. A total of 180 male yellow broilers were randomly divided into an unchallenged control and an Eimeria challenge treatment group within 18 floor pens (10 chicks/pen, 9 replicate pens/group). On day 10, 90 chicks received a cocktail of E. maxima, E. acervulina, and E. tenella oocysts (10⁵/chick) to induce coccidial infection, and the other 90 received an aliquot of PBS. The Eimeria challenge resulted in increased bird feed consumption and FCR from day 11 to 21 (all P < 0.01). Higher fecal Eimeria counts, duodenal, jejunal, and cecal lesions were observed in the challenge group on day 12, 15, 15, 18 respectively (all P < 0.05). Furthermore, the infected birds had larger livers and small intestines, deeper villus crypt, and decreased expression of Claudin-1 on day 21 (all P < 0.05). The 16S rRNA sequencing indicated that alpha diversity (Sobs, Shannon, Simpson, Ace, or Chao) of cecal microbials was not affected by Eimeria challenge (all P > 0.05). However, the PCoA and LEfSe analyses indicated that the Eimeria challenge altered microbial distribution by decreasing the abundance of Firmicutes and enriching the abundance of Proteobacteria at the phylum level. At the genus level, Clostridia vadin BB60 and Lachnospiraceae NK4A136 group were reduced, while Escherichia-Shigella were enriched in the challenged yellow broilers (all P < 0.05). Correlation analyses demonstrated that the birds with higher Lachonospiraceae NK4A136 group and Clostridia vadin BB60, and lower Escherichia-Shigella in their cecal content gained more BW and reached a lower FCR from day 11 to 21 (all P < 0.05). In conclusion, Eimeria infection compromised feed efficiency of yellow broilers by damaging intestinal barrier and shifting cecal microbiota towards colonizers associated with poor performance. Restoring the dysbiotic microbiome could be a potential strategy for improving feed efficiency in yellow broilers under coccidial challenge.

Newly hatched male layer chicks are considered as “by-products” in the egg industry and must be humanely euthanized at the hatchery. Instantaneous mechanical destruction (maceration) is the predominant euthanasia method applied in poultry hatcheries and is approved by the American Veterinary Medical Association (AVMA). However, maceration is not perceived by the public to be a humane means of euthanasia. The effects of alternative euthanasia methods, including carbon dioxide (CO₂) or nitrogen (N₂) inhalation, and a commercial negative pressure stunning system on behavioral and physiological responses of day-of-hatch male layer chicks, were evaluated in a field trial. Chick behaviors, including ataxia, loss of posture, convulsions, cessation of vocalization, and cessation of movement, were monitored. Serum hormones were assessed at the end of each of the alternative euthanasia treatments, including a control group allowed to breathe normal atmospheric air. The N₂ method induced unconsciousness and death later than the CO₂ and negative pressure methods, and increased serum corticosterone concentrations of neonatal chicks. Carbon dioxide inhalation increased serotonin concentrations as compared to controls, as well as the N₂ and the negative pressure methods. The behavioral and physical responses observed in this study suggest that both CO₂ inhalation and negative pressure stunning can be employed to humanely euthanize neonatal male layer chicks.