Broiler responses to dietary 3,4,5-trihydroxybenzoic acid and oregano extracts under Eimeria challenge conditions

Major histocompatibility complex genes exhibit a potential immunological role in mixed Eimeria-infected broiler cecum analyzed using RNA sequencing

OBJECTIVE

This study was conducted to investigate the differential expression of the major histocompatibility complex (MHC) gene region in Eimeria-infected broiler.

METHODS

We profiled gene expression of Eimeria-infected and uninfected ceca of broilers sampled at 4, 7, and 21 days post-infection (dpi) using RNA sequencing. Differentially expressed genes (DEGs) between two sample groups were identified at each time point. DEGs located on chicken chromosome 16 were used for further analysis. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis was conducted for the functional annotation of DEGs.

RESULTS

Fourteen significant (false discovery rate <0.1) DEGs were identified at 4 and 7 dpi and categorized into three groups: MHC-Y class I genes, MHC-B region genes, and non-MHC genes. In Eimeria-infected broilers, MHC-Y class I genes were upregulated at 4 dpi but downregulated at 7 dpi. This result implies that MHC-Y class I genes initially activated an immune response, which was then suppressed by Eimeria. Of the MHC-B region genes, the DMB1 gene was upregulated, and TAP-related genes significantly implemented antigen processing for MHC class I at 4 dpi, which was supported by KEGG pathway analysis.

CONCLUSION

This study is the first to investigate MHC gene responses to coccidia infection in chickens using RNA sequencing. MHC-B and MHC-Y genes showed their immune responses in reaction to Eimeria infection. These findings are valuable for understanding chicken MHC gene function.

Responses of broilers challenged by Eimeria maxima fed with different levels of dietary balanced protein

This study aimed to evaluate the effects of different dietary balanced protein (BP) levels on the gut health, amino acid apparent ileal digestibility (AID), footpad dermatitis lesions, and litter quality in broiler chicks infected with Eimeria maxima. A total of 2400 male 14-day-old Cobb500 broilers were randomly allotted into 10 treatments with six replications containing 40 birds each in a factorial design of 5 × 2. The treatments consisted of five levels of BP (6.66%, 13.32%, 19.98%, 26.64%, and 33.3%), and broilers unchallenged (NCH) or challenged (CH). Broilers in the CH group received 1 mL of Eimeria maxima inoculum (7 × 103 sporulated oocysts/mL). Oocyst count in excreta, visual intestinal modifications score, morphology, and morphometrics of the ileum were used to determine gut health status. Additionally, amino acids and CP AID, litter quality, and footpad dermatitis were evaluated. An ANOVA and Kruskal-Wallis tests followed by post-hoc tests were performed. The oocyst count in the CH group increased with an increase in dieatary BP (P = 0.08). The incidence of intestinal modifications was higher in the CH group (P < 0.05) and increased with increasing dietary BP (P < 0.05). Morphometrics were impaired by the challenge (P < 0.05), and by the two highest BP levels (P < 0.05). Amino acids AID (methionine, methionine + cystine, arginine, and serine) were reduced by E. maxima challenge. An increase in dietary BP resulted in poor litter quality and high prevalence of of footpad dermatitis (P < 0.05). The E. maxima challenge and increased BP decreased gut health, litter quality, and cause a high incidence of footpad dermatitis.

Effects of green tea phytosome on growth performance and intestinal integrity under coccidiosis infection challenge in broilers

This research examined the effects of feeding phytosomal green tea on broilers infected with coccidia. To provide phytosome, green tea extract was loaded into soy lecithin. Groups of chicks included uninfected and untreated control (NC), infected and untreated control (PC), infected and treated with salinomycin control (SC), infected and treated with 300 and 400 mL of green tea extract (GTE300, GTE400), infected and treated with 200, 300, 400 and 500 mL of green tea phytosome (GTP200, GTP300, GTP400, and GTP500). At 14-days posthatch, chickens were orally gavaged, except the NC group with a coccidia vaccine 30 times larger than the approved dose. Body weight (BW), feed intake (FI), and feed conversion ratio (FCR) were determined at 7, 14, 20, 28, 35, and 42 d. The characteristics of the carcass, internal organs and intestinal morphology were assessed on d 42. Applying overdose of coccidiosis vaccine showed experimental Eimeria infection, led to decrease in FI and BW, and increased FCR compared to PC group (P < 0.001). Meanwhile salinomycin, green tea extract, and green tea phytosome compensated the negative effects of Eimeria infection on growth performance. The treatments did not affect carcass, breast, and thigh relative weights. Interestingly, abdominal fat percent was significantly lower in chickens fed GTP300, GTP400, and GTP500 than in those fed GTE300, GTE300, and GTP200 (P < 0.0001). In comparison to the basal diet plus green tea extract forms and NC groups, the PC group increased the relative weights of the liver, spleen, bursa, and pancreas (P < 0.05). The highest values of villus height and villus height to crypt ratio were obtained in duodenum, jejunum and ileum in GTP300 group (P < 0.0001), while, villi diameter in duodenum and ileum decreased the most in GTP300 and GTP500, respectively (P < 0.0001). Consequently, as natural anticoccidial drug delivery systems, 300 mL of green tea phytosome can be introduced as the optimal dose to maximize the benefits of phytosome for intestinal integrity and reduce the consumption of green tea extract.

Effect of Dietary Organic and Inorganic Sulfur on the Performance of Coccidiosis Vaccine Challenged Broiler Chickens

The objective of this study was to evaluate the effects of dietary sulfur from either organic (methyl sulfonyl methane, MSM) or inorganic (sodium sulfate, SS) sources on the growth performance of broiler chickens challenged against a high-dose coccidiosis vaccine. A total of 320 day-old Ross 308 broiler chicks were randomly placed into 32 pens of 10 birds each (keeping 16 pens/control group and 8 pens/treatment group until 21 days post-hatch) and reared for 28 days. The experimental diets were formulated by mixing a corn and soybean meal-based control diet with MSM or SS. At 21 days post-hatch, half (n = 8) of the control and all of the sulfur-added diet-fed (i.e., MSM and SS) groups were challenged with a 30-fold dose of a commercially available Eimeria vaccine (Livacox® T coccidiosis vaccine). Unchallenged control chicks (n = 8) were considered as the negative control group. At 21 days (before coccidiosis vaccine challenge), the production parameters and cecal short-chain fatty acids were not affected by dietary treatments. The concentrations of total antioxidant capacity in liver samples were elevated in both the MSM and SS groups compared with the control group (p = 0.001). During 21 to 28 days (i.e., one week post coccidiosis vaccine challenge), challenge tended to lower body weight and feed intake by an average of 5.3% (p = 0.262) and 2.8% (p = 0.504), respectively, but to increase the feed conversion ratio by an average of 2.7% (p = 0.087) compared with the non-challenged control groups. None of dietary sulfur groups affected the body weight gain, feed intake, or feed conversion ratio of vaccine-challenged chickens. Mild Eimeria-specific lesions were noted in duodenum (p = 0.006), jejunum (p = 0.017), and ceca (p = 0.047), but dietary sulfur treatments did not affect the Eimeria-induced gut lesion scores. At 28 days, Eimeria challenge significantly impaired (p = 0.001) the apparent ileal digestibility of crude protein and crude ash compared with the naïve control group. Dietary MSM increased the apparent ileal digestibility of crude ash by 15.5% on average compared with the coccidiosis vaccine control group. We conclude that dietary antioxidant sulfur of organic or inorganic origins at the inclusion level (i.e., 0.7 g sulfur/kg of diet) has a limited effect on the growth performance of chickens challenged with coccidiosis vaccine.