Reduction of Salmonella enterica serovar enteritidis colonization in 20-day-old broiler chickens by the plant-derived compounds trans-cinnamaldehyde and eugenol.

The efficacies of trans-cinnamaldehyde (TC) and eugenol (EG) for reducing Salmonella enterica serovar Enteritidis colonization in broiler chickens were investigated. In three experiments for each compound, 1-day-old chicks (n = 75/experiment) were randomly assigned to five treatment groups (n = 15/treatment group): negative control (-ve S. Enteritidis, -ve TC, or EG), compound control (-ve S. Enteritidis, +ve 0.75% [vol/wt] TC or 1% [vol/wt] EG), positive control (+ve S. Enteritidis, -ve TC, or EG), low-dose treatment (+ve S. Enteritidis, +ve 0.5% TC, or 0.75% EG), and high-dose treatment (+ve S. Enteritidis, +ve 0.75% TC, or 1% EG). On day 0, birds were tested for the presence of any inherent Salmonella (n = 5/experiment). On day 8, birds were inoculated with ∼8.0 log(10) CFU S. Enteritidis, and cecal colonization by S. Enteritidis was ascertained (n = 10 chicks/experiment) after 24 h (day 9). Six birds from each treatment group were euthanized on days 7 and 10 after inoculation, and cecal S. Enteritidis numbers were determined. TC at 0.5 or 0.75% and EG at 0.75 or 1% consistently reduced (P < 0.05) S. Enteritidis in the cecum (≥3 log(10) CFU/g) after 10 days of infection in all experiments. Feed intake and body weight were not different for TC treatments (P > 0.05); however, EG supplementation led to significantly lower (P < 0.05) body weights. Follow-up in vitro experiments revealed that the subinhibitory concentrations (SICs, the concentrations that did not inhibit Salmonella growth) of TC and EG reduced the motility and invasive abilities of S. Enteritidis and downregulated expression of the motility genes flhC and motA and invasion genes hilA, hilD, and invF. The results suggest that supplementation with TC and EG through feed can reduce S. Enteritidis colonization in chickens.

Assessing the consequences of the pesticide methoxychlor: neuroendocrine and behavioral measures as indicators of biological impact of an estrogenic environmental chemical.

Japanese quail provide an advantageous avian model for assessing long-term biological consequences of endocrine disrupting chemicals (EDCs). These studies examined route of exposure and vulnerability to biological impact of EDCs over the life cycle in a precocial avian model, the Japanese quail. Embryonic exposure occurs with maternal deposition and methoxychlor (MXC) accumulated with maternal exposure. Egg injections of MXC or estradiol at selected stages of development impacted hypothalamic neuroendocrine systems in hatchlings and affected sexual maturation, with evidence for long-term effects on neurotransmitters and male behavior. Two-generation dietary studies were conducted to examine transgenerational effects of EDCs. Adult quail (P1) were exposed to dietary MXC (0, 0.5 and 5 ppm), with continued exposure in their offspring (F1), and control diet for all F2 chicks. Toxicological end points, including fertility, hatching success, and 14-day viability were unaffected. F1 and F2 male offspring from MXC-treated pairs MXC had impaired mating behavior and altered plasma hormones. These studies confirm neuroendocrine and behavioral measures as reliable indices of exposure to an estrogenic EDC. Moreover, maternal deposition remains a primary route of EDC exposure, with potential deleterious consequences for field birds, especially precocial species that appear to be particularly sensitive to embryonic EDC exposure.